Insights into the adsorption of CO2 generated from synthetic urban wastewater treatment on olive pomace biochar

In this investigation, a sustainable and low-cost method to capture CO₂ generated from the treatment of urban wastewater was evaluated. We studied the adsorption of CO₂ on olive pomace biochar. The experiments of degradation of synthetic wastewater mimicking effluents of municipal wastewater treatment plant (WWTP) with an initial Total Organic Carbon (TOC) concentration of 10 mg L^-1 were conducted by using the UV-C/H₂O₂ process in the absence or presence of biochar. The biochar was placed in a fixed bed column through which air from the UV reactor was circulated. First, the effects of different parameters such as H₂O₂ initial concentration and pH on wastewater mineralization efficiency were determined. Total Organic Carbon (TOC) removal was 87% in 2 h under optimal degradation conditions. The maximal concentration of CO_2(gas) in air, in a closed system (air volume: 7.3 10^-4 m³), after 11 h was 12,500 μmol mol^-1 in the absence of biochar and only 150 μmol mol^-1 when 10 g biochar were used. The results proved that by combining biochar with oxidative degradation of organic compounds, it is possible to mineralize organic compounds and reduce the requisite CO₂ emissions by about 99%. The experimental equilibrium results were fit well with both Langmuir and Freundlich isotherms models concluding that CO₂ adsorption on biochar followed both chemisorption and physisorption and both monolayer and multi-layer CO₂ adsorption could occur. The total desorption of CO₂ from biochar was reached in 120 min by simultaneously increasing the temperature to 150 °C and introducing a purge N_2(gas).

Prognostic impact of right ventricular strain in isolated severe tricuspid regurgitation

Background

Right ventricular (RV) systolic function is determinant in the evaluation of patients with severe tricuspid regurgitation (TR). Timely detection of RV dysfunction with conventional 2D echocardiography is challenging. RV strain has emerged as an accurate and sensitive tool for evaluation of RV function with the capability of detecting subclinical RV dysfunction.

Purpose

This study was aimed to evaluate the prognostic value of RV strain parameters in consecutive stable patients with severe TR.

Methods

Consecutive patients in stable clinical status with at least severe TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic following a comprehensive clinical protocol were included. Patients with previous episodes of heart failure or scheduled for TV intervention were excluded. RV systolic function was measured with conventional echocardiographic indices (RV fractional area change [FAC], tricuspid annular plane systolic excursion [TAPSE], DTI S wave [`S]) and with Speckle-tracking echocardiography (STE) derived automatic peak global and free wall longitudinal strain (RV-GLS and RV-FWLS respectively) using the EPIQ system (Philips Medical Systems, Andover, Massachusetts). A combined endpoint of hospital admission due to heart failure (HF) or all-cause mortality was defined. The interobserver variability of RV strain was assessed in 20 randomly selected patients.

Results

A total of 176 patients were included in this study. Strain parameters detected higher percentage of RV dysfunction compared to conventional indices (figure 1). After a median follow-up of 28 months (IQR: 15–48 months), n=65 patients (37%) reached the combined endpoint. 65 (37%) were admitted for right heart failure and 8% of the population (n=14) died. Cumulative event-free survival was significantly worse in patients with impaired RV-GLS and RV-FWLS. Conventional indices of RV systolic function were not associated with outcomes (p>0.05 for all). In a multivariable analysis (in a model including NYHA class, BNP values, biplane VC, RV end-diastolic area, and RV-FWLS), RV-FWLS was an independent predictors of heart failure and CV mortality (figure 1 and 2; LR χ2: 40.2, p<0.001). Inter-observer agreements for RV strain values were high (intraclass correlation coefficient for RV-GLS and RV-FWLS, r=0.96 and r=0.98 respectively)

Conclusion

Clinical outcomes demonstrate that RV strain parameters are superior to conventional indices of RV function in patients with isolated ≥ severe TR and absence of previous episodes of heart failure. Among all parameters of RV function, RV-FWLS is the strongest independent predictor of mortality and HF.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto Carlos III

Clinical utility and prognostic value of right atrial function in severe tricuspid regurgitation. One more piece of the puzzle

Background

Optimal management of severe tricuspid regurgitation (TR) remains controversial. While right ventricular systolic function is an established prognostic marker of outcomes, the potential role of right atrial (RA) function is unknown.

Purpose

This study was aimed to describe RA function by 2D speckle tracking echocardiography (STE) in severe TR and to evaluate its potential association with cardiovascular outcomes

Methods

Consecutive patients with at least severe TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic following a comprehensive clinical protocol were included. Consecutive control subjects and patients with permanent atrial fibrillation (AF) were included for comparison. RA function was measured with 2D-STE and 3 components of RA function were calculated: reservoir (RASr), conduit (RAScd) and contractile (RASct) RA values using an automatic 2D strain analytical software (AutoStrain, Philips Medical Systems the EPIQ system, Figure 1). A combined endpoint of hospital admission due to heart failure (HF) or all-cause mortality was defined. The interobserver variability of RA strain was assessed in 30 randomly selected subjects (20 TR+5 AF+5 controls).

Results

A total of 176 patients with severe TR, 20 AF patients and 20 controls subjects were included in this study. Patients with at least severe TR showed lower RASr and RAScd compared to controls and to AF patients (Figure 1 and Table 1, p<0.05). After a median follow-up of 28 months (IQR: 15–48 months), n=65 patients with severe TR (37%) reached the combined endpoint. 65 (37%) were admitted for right heart failure and 8% of the population (n=14) died. Patients with events showed lower values of RASr and RAScd (p<0.01 for both). Between both parameters RASr was more strongly associated with outcomes compared to RAScd (AUC 0.74 vs. 0.65, p<0.01). RASr was an independent predictor of heart failure and all cause mortality adjusted by additional imaging prognostic parameters in a multivariable analysis (biplane vena contracta, RV end-diastolic area, and RV-free wall longitudinal strain [LR χ2: 49.7, p<0.001]). RA area or volume was not associated with outcomes. A cut-off value of RASr of <9.4% held the best accuracy to predict outcomes (adjusted HR 3.2 (1.81–5.84), p<0.001, Figure 1). Inter-observer agreements for RA strain values across the whole cohort were high (intraclass correlation coefficient for RASr, RAScd and RASct, r=0.95, r=0.86, r=0,92 respectively)

Conclusions

Evaluation of RA function by 2D-STE is feasible, reproducible and is an independent predictor of heart failure and all-cause mortality in patients with at least severe TR.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): INSTITUTO CARLOS III

The 4A classification for patients with tricuspid regurgitation

Background

Significant Tricuspid Regurgitation (TR) is associated with increased morbi-mortality. Clinical evaluation of TR patients is challenging.

Purpose

To establish a new clinical classification specific for patients with TR, the 4A classification, and evaluate its performance on prognosis.

Methods

Consecutive patients with isolated at least severe TR and absence of episodes of heart failure (HF) evaluated in the Heart Valve Clinic were included. Signs and symptoms of Asthenia, Ankle swelling, Abdominal pain or distention and/or Anorexia where registered, follow up was performed every 6 months. 4A classification ranged from A0 (no A) to A4 (three or four A's present). A combined endpoint of hospital admission due to right HF and cardiovascular mortality was defined.

Results

135 patients with significant TR between 2016 and 2021 were included (69% females, mean age was 78±7 years). During a median follow-up of 26 months (IQR: 10–41 months), n=53 patients (39%) reached the combined endpoint. 52 (38%) admitted for heart failure and 11% (n=15) died. At baseline 94% of patients were in NYHA I or II whereas 24% presented A2 or A3. The presence of A2 or A3 showed a high incidence of events (figure). The change in 4A class and GGT remained independent predictor of HF and cardiovascular mortality (adjusted HR per unit of change of 4A class 1.95 [1.37–2.77], p<0.001)

Conclusions

For the first time, we show the use of a new clinical classification, specific for patients with TR based on signs and symptoms of right HF that is prognostic of events.

Funding Acknowledgement

Type of funding sources: None.

Why does CRT work better in women?

Introduction

It has been recently postulated that cardiac resynchronization therapy (CRT) might have a higher efficacy in women, with a greater reverse cardiac remodeling in this population. The reasons for these differences are not yet completely understood. We aimed to detect sex differences in the degree of ventricular asynchrony (VA) and mitral regurgitation (MR) in patients undergoing CRT implantation.

Methods

We analyzed baseline characteristics of a prospective international clinical trial that compared CRT response rate in a HF population with a comparable distribution of men and women (BIOWOMEN). A total of 408 patients were analyzed. The degree of mitral regurgitation and intra and inter-ventricular asynchrony was assessed by independent echocardiographers in a core lab. Inter-ventricular asynchrony was defined as an interventricular mechanical delay greater than 40ms and intra-ventricular asynchrony as differences greater than 50ms among regional pre-ejection periods. Multivariable logistic regression was performed using commercial data analysis software.

Results

As expected, ventricular asynchrony was dependent on QRS duration and the presence of LBBB (p<0.01). Baseline QRS duration was significantly shorter in women than men (155.85±19.0 in women vs 160.4±21.6, p=0.02). However, for a similar QRS duration, there were no differences in asynchrony parameters between the two groups (p=0.43; Figure 1). Female sex was associated with a significantly higher proportion of mitral regurgitation for a given QRS duration, which was independent of the etiology (p=0.05).

Conclusions

In our analysis, for a given QRS duration there was not a higher degree of asynchrony in women with HF. However, female sex was associated with a significantly higher proportion of mitral regurgitation for a given QRS duration irrespective of baseline HF etiology. Further investigations are needed to establish a possible link between these findings and better CRT outcomes in women.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): BIOTRONIK SE & Co. KG

STREI: a new index of right heart function in isolated severe tricuspid regurgitation by Speckle tracking Echocardiography

Background

Right ventricular (RV) performance is key in the management of patients with severe tricuspid regurgitation (TR); detection of RV dysfunction is crucial to identify on time patients that benefit from valve intervention. Conventional parameters of RV function by 2D echocardiography are influenced by changes on preload conditions and can remain unaffected until late stages of the disease. The right atrium (RA) has an important role in modulating RV filling and RA performance is impaired in severe TR. Potentially, an index that combines RV and RA function may reflect a broader view of the effects of severe TR in right heart function.

Purpose

1) to evaluate the clinical utility of combining RV and RA strain for prediction of CV outcomes and 2) to design a novel index by Speckle-tracking echocardiography (STREI index) that integrates RA and RV information

Methods

Consecutive patients with at least severe TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic following a comprehensive clinical protocol were included. Consecutive control subjects and patients with permanent atrial fibrillation (AF) were included for comparison. Reservoir RA strain (RASr) and RV-free wall longitudinal strain (RV-FWLS) analysis were performed using novel, automated 2D strain analytical software (AutoStrain, Philips Medical Systems the EPIQ system, Figure 1). Novel STREI index was calculated with the formula: [2 × RV-FWLS] + RASr in absolute numbers.

A combined endpoint of hospital admission due to heart failure (HF) or all-cause mortality was defined. The interobserver variability of RA strain was assessed in 30 randomly selected subjects (20 TR+5 AF+5 controls).

Results

A total of 176 patients with severe TR, 20 AF patients and 20 controls subjects were included in this study. Patients with TR showed lower STREI values compared to controls and to AF patients (TR vs. controls vs. AF: 55±18 vs. 116±12 vs. 70±13, p<0,001). After a median follow-up of 28 months (IQR: 15–48 months), n=65 patients with severe TR (37%) reached the combined endpoint. Patients with both abnormal strains (abnormal RV-FWLS and abnormal RASr strain) showed a significantly higher rate of events (Figure 2A). In a multivariable analysis, STREI index was an independent predictor of HF and mortality adjusted by vena contracta, RV end-diastolic area, NYHA class and BNP values (LR χ2: 46,1, p<0,001). A cut off value of STREI index <50% held the best accuracy to predict outcomes. An abnormal STREI index was associated with 6,1-fold increased risk of HF or death (HR 6,9 (3,9–12,3), p<0,001, Figure 2B) Inter-observer agreements for STREI values were high (intraclass correlation coefficient = 0,96).

Conclusion

STREI index is a feasible and reproducible new parameter of RV performance that independently predicts outcomes in patients with severe TR. Randomized studies should confirm its potential to identify those patients that benefit from earlier valve interventions.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto Carlos III

Left ventricular thrombus and anticoagulation: how long should we treat?

Background

Left ventricular thrombus (LVT) is a potential complication of acute myocardial infarction and is associated with a high rate of thromboembolic events. With the advent of more potent antithrombotic medications and quicker reperfusion strategies, the incidence of LVT has been reduced. However, current guidelines recommendations are based on older evidence and some aspects of the treatment are being questioned, such as the optimal duration of anticoagulation.

Purpose

To determine how length of anticoagulation influences the risk of thromboembolic events and mortality in a tertiary-care cardiac center with primary percutaneous coronary intervention (PCI) capability.

Methods

A cohort of consecutive cases of patients with IVT diagnosed by transthoracic echocardiography between 2014 and 2020 was retrospectively analyzed.

Results

A total of 72 cases of LVT were identified. Etiology was ischemic cardiomyopathy in 60 (82.0%) patients and 13 (20.0%) were female. LVT was diagnosed in the setting of acute myocardial infarction in 23 (32.0%) of cases. Prolonged anticoagulation regimes were significantly associated with fewer systemic thromboembolic events (21.4% vs 6.1%; p=0.04), without a significant effect on mortality (Figure 1).

Conclusion

Clinical manifestations and epidemiology of LVT has recently changed after the advent of improved treatments. In our cohort, an indefinite anticoagulation strategy was significantly associated with fewer thromboembolic events, suggesting that future investigations should clarify these issues.

Funding Acknowledgement

Type of funding sources: None.

Severity of tricuspid regurgitation (TR) only based in echo parameters? The failure of guidelines. The 4A in patients with significant TR as a new clinical score to evaluate patients with TR

Background

Significant Tricuspid Regurgitation (TR) is associated with increased morbi-mortality. Symptoms due to TR are often insidious and not always characterized by dyspnea. Identification of symptoms and optimal timing for intervention is challenging and intervention is often preformed late. A more specific clinical classification focused on the detection of systemic congestion may help identify those who may benefit from an earlier intervention.

Purpose

To evaluate the prognostic impact of a new proposed “4A” clinical score: Asthenia, Ankle swelling, Abdominal pain or distention and/or Anorexia, in patients with significant TR.

Methods

Consecutive patients in stable clinical condition evaluated in the Heart Valve Clinic with significant TR (moderate to severe, severe, massive or torrential TR) were included. Signs and symptoms of Asthenia, Ankle swelling, Abdominal pain or distention and/or Anorexia (“4A score”) where registered, follow up was performed every 6 months. The 4A clinical score ranged from 0 (no A) to 4 (all four A's present). The difference in the 4A score between the first and last visit was determined. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined.

Results

86 patients were included in this study (age 76±11 years, 70% female, 87% functional TR). At first visit, 92% were in NYHA class I or II and 77% had a 0 or 1 “4A score”. After a median follow-up of 24 months (IQR: 11–35 months), “4A score” was significantly impaired (score mean difference: 0.42±0.8) and only 59% remained with a 0 or 1 “4A score”. 32.6% of the patients (n=28) experienced the combined endpoint. The change in 4A score was a significant predictor of events (hazard ratio per unit 1.88 [1.22–2.88], p=0.004)

Conclusion

We demonstrate for the first time a new clinical score predictive of right heart failure and death in patients with significant TR.

Funding Acknowledgement

Type of funding sources: None.

Mortality and heart failure in patients with severe tricuspid regurgitation. Impact of RV volumes and function by CMR

Background and objectives

Right ventricle (RV) dilatation and dysfunction are established criteria for intervention in patients with significant tricuspid regurgitation (TR); however defined thresholds to support intervention are lacking. As a result the optimal timing for surgery in TR remains controversial and surgery is commonly undertaken at a late stage.

Purpose

To describe predictive cut-off values of RV size and function of poor prognosis in asymptomatic patients with significant TR.

Methods

Consecutive patients in stable clinical condition evaluated in the Heart Valve Clinic with significant TR (severe, massive or torrential TR) undergoing a Cardiac Magnetic Resonance (CMR) study were included. Conventional parameters of biventricular volume and function were assessed in all patients. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined.

Results

75 patients were included in this study (age 75±8 years, 75% female, 91% functional TR). During a median follow-up of 3 years (IQR: 1.4–3.9 years), 39% of the patients (n=29) experienced the combined endpoint. After adjusting for age and LVEF in a multivariate Cox proportional model, RV-EDV and RVEF were independently associated with cardiovascular mortality and heart failure. Thresholds of RV-EDV ≥100 ml/m2, RV-ESV ≥40 ml/m2 and RVEF ≤58% held the best accuracy to predict outcomes (figure 1). Regression spline model for RVEF and outcomes are presented in the figure 2. They show that RV function negatively impacted event-free survival, with an increase in the HR spline function near the crossing value (red line, RVEF ≤58%). In multivariable analysis, following adjustment for age and LVEF, a value of RVEF ≤58% and RV-EDV ≥100 ml/m2, was associated with 2.29, and 3.91-fold increased risk of heart failure or cardiovascular death respectively (RVEF Hazard Ratio (HR): 2.29 [1.06–4.9], p=0.03, and RV-EDV HR: 3.91 [1.56–9.82], p=0.004).

Conclusion

RV size and function are crucial for determining optimal timing for TR intervention. For the first time, cut-off values of RV volume and function are defined in a cohort of consecutive patients based on outcome data. Proposed values provide a basis for prospective studies to establish definitive optimal surgical timing for severe TR.

Funding Acknowledgement

Type of funding sources: None. Figure 1. ROC and Cox regressions analysisRegression spline curve

Prognostic value of right ventricular systolic function by speckle tracking echocardiography beyond conventional echocardiography in significant tricuspid regurgitation

Background

Right ventricular (RV) systolic function is determinant in the evaluation of patients with significant tricuspid regurgitation (TR). Timely detection of RV dysfunction with conventional 2D echocardiography is limited by the geometry and position of the RV. RV strain has emerged as an accurate and sensitive tool for evaluation of RV function with the capability of detect subclinical RV dysfunction

Purpose

This study was aimed to evaluate the prognostic value of RV strain in consecutive patients with significant TR, in comparison with conventional parameters of RV systolic function.

Methods

Consecutive patients in stable clinical status with significant TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic were included. RV systolic function was measured with conventional echocardiographic parameters (RV fractional area change [FAC], tricuspid annular plane systolic excursion [TAPSE]), DTI S wave (S') and with STE derived automatic peak global and free wall longitudinal strain (GLS, FW-LS respectively) using the EPIQ system (Philips Medical Systems, Andover, Massachusetts). A combined endpoint of hospital admission due to right heart failure or cardiovascular mortality was defined.

Results

A total of 130 patients were included (mean age was 75±17 years, 69% females, 93% in NYHA I/II). According to etiology, 14% were primary TR and 86% were functional (49% due to corrected left valve disease and 37% due to tricuspid annulus dilatation). Mean values of RV function parameters are shown in the table. During a mean follow up of 18±8 months, n=39 patients (30%) reached the combined endpoint. Patients with events showed impaired RV GLS and FW-LS. Both parameters were predictive of the combined endpoint (table 1). Conventional parameters of RV systolic function were not associated with outcomes (p>0.05 for all).

Conclusion

In patients with severe TR, RV strain values are superior to conventional parameters to detect RV dysfunction. Among different measurements of RV function, RV GLS and FW-LS were the only predictors of poor prognosis. These parameters should be included in the serial evaluation of these patients.

Funding Acknowledgement

Type of funding sources: None. RV parameters

Impact of previous cardiac conditions in prognosis and clinical management of patient with COVID-19 infection

Background

Recent studies suggest a higher mortality rate because of COVID-19 in patients with previous cardiac conditions compared to those without. Given the limited resources of intensive care units (ICU) during the pandemic outbreak, this fact has important implications.

Purpose

The main purpose of this study was to compare the 30-day mortality of the COVID-19 infection in patients with and without previous cardiac conditions. The secondary end point was to assess the differences in clinical severity of the infection (as development of Acute Respiratory Distress Syndrome – ARDS) and ICU admission amongst these patients.

Methods

A total of 1708 consecutive patients were prospectively included. The inclusion criteria were: a confirmed positive diagnosis of COVID-19 infection by PCR and being admitted to our centre between 18th and 23rd March 2020 and 22nd August and 9th January 2021. Patients were classified in two groups according to the presence of previous cardiac conditions (defined as previous history of myocardial infarction, heart failure and atrial fibrillation). Other comorbidities were extensively explored and Charlson Comorbidity Index was calculated. A propensity-score matching was performed and 145 patients with previous cardiac conditions were matched with 145 patients without.

Results

The group of patients with a previous cardiac condition included 421 patients (24.6%). The crude analysis showed a higher 30-day mortality rate among patients with previous cardiac affections (35.6% vs. 14.6%, p<0.001). They were also less likely to be admitted to the ICU (9.8% vs. 6.2%, p=0.022) and had a higher prevalence ARDS (48.9% vs. 33.9%, p<0.001). In the matched cohort, there were no significant differences between both groups regarding mortality (24.8% in the group of patients with previous cardiac conditions vs. 31.0%, p=0.272) nor ARDS prevalence (50.3% vs. 53.1%, p=0.655). There was a trend toward patients with previous cardiac conditions to be less likely to be admitted to the ICU (4.8% vs. 9.7%, p=0.090).

Conclusions

Patients with a personal history of previous cardiac conditions were less likely to be admitted to the ICU. However, our results show that when comparing cohorts with similar comorbidity burden, a previous cardiopathy “per se” does not significantly increase the risk of death in patients with a concomitant COVID infection.

Funding Acknowledgement

Type of funding sources: None. Mortality unmatched vs matched cohort

Prognostic impact of different parameters of right ventricular systolic function in patients with significant tricuspid regurgitation. A cardiac magnetic resonance study

Background

Right ventricle (RV) dysfunction represent an established criteria for intervention in patients with significant tricuspid regurgitation (TR). RV ejection fraction (RVEF) by Cardiac Magnetic Resonance (CMR) is considered the gold standard of RV function; however it is influenced by changes of preload conditions and may remain unaffected until late stages in severe TR. Novel measures of RV function such as RV longitudinal shortening (RV-LS) and effective RV ejection fraction (eRVEF) may be earlier markers of RV dysfunction.

Purpose

To compare the prognostic impact of conventional and novel parameters of RV systolic function.

Methods

Consecutive patients in stable clinical condition evaluated in the Heart Valve Clinic with significant TR (severe, massive or torrential TR) undergoing a CMR study were included. In addition to conventional parameters of biventricular volume and function, RV-LS and eRVEF were assessed as novel parameters of RV function. RV-LS was assessed in the 4-chamber view by measuring the displacement of the tricuspid annulus during the cardiac cycle. The length between the epicardial border of the LV apex and the middle of a line connecting the origins of the tricuspid valve leaflets was measured in both end-systole and end-diastole. Effective RVEF (eRVEF) is a measure of RV global systolic function but corrected by TR volume. Both formulas are represented in figure 1. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined

Results

75 patients were included in this study (age 75±8 years, 75% female, 91% functional TR) During a median follow-up of 3 years (IQR: 1.4–3.9 years), 39% of the patients (n=29) experienced the combined endpoint. RV-LS and eRVEF identified higher rates of RV dysfunction than RVEF. RV-LS of ≥−14% and eRVEF of ≤34% were associated with impaired prognosis (figure 2). After adjustment of age and LVEF, both eRVEF (adjusted HR per abnormal value: 5.29 95% CI, [2.25–12.4]) and RV-LS (adjusted HR per abnormal value: 3.46, 95% CI, [1.13–9.17]) were significantly associated with outcomes. Among all parameters of RV function, eRVEF was the strongest predictor of outcomes, incremental to RVEF (Δ C-statistic 0.139 [0.040–0.237], p=0.005).

Conclusion

RV function is crucial for determining optimal timing for TR intervention. RV-LS and eRVEF identify higher rates of RV dysfunction beyond RVEF. Among all measures of RV function, eRVEF held the strongest association with outcome, incremental to RVEF.

Funding Acknowledgement

Type of funding sources: None. Figure 1. RV-LS and eRVEF calculationFigure 2. Kaplan Meier Curves

Mortality and heart failure in patients with severe tricuspid regurgitation. Risk stratification based on TR severity by CMR

Background

Tricuspid regurgitation (TR) is related to poor prognosis independently of the etiology. A new scale classification has been proposed to better characterize the grading of more than severe TR. Massive and torrential TR seem to have worse prognosis based on echocardiographic studies.

Purpose

To stratify patients' risk based on TR severity by CMR

Methods

Consecutive patients in stable clinical condition evaluated in the Heart Valve Clinic with significant TR (severe, massive or torrential TR) with a contemporaneous echo and CMR were included. TR severity was evaluated by vena contracta (VC) and ERO method, using EPIQ system (Phillip Medical system Andover, Massachusets) and by TR regurgitant fraction (TRF) using a 1.5 Tesla CMR Philips scanner. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined.

Results

75 patients were included in this study (age 75±8 years, 75% female, 91% functional TR). According to echocardiography 75% were severe, 15% were massive and 10% were torrential TR. Patients with massive and torrential TR showed higher RV end-diastolic volume and lower RVEF. A TRF >50% held the best accuracy to define massive / torrential TR. During a median follow-up of 3 years (IQR: 1.4 – 3.9 years), 39% of the patients (n=29) experienced the combined endpoint. After adjusting for age and LVEF in a multivariate Cox proportional model, TRF was independently associated with cardiovascular mortality and heart failure (hazard ratio per 1%=1.05, [1.02–1.08], p<0.001). Patients were stratified in 3 groups according to TR severity. Patients with TRF ≤40% showed the lowest incidence of events and those with TRF ≥50% experienced the worse prognosis (log rank=0.001, figure)

Conclusion

Patients with massive/torrential TR are populations at higher risk of heart failure and mortality. Risk stratification strategies may identify the patients who benefit the most of intensive therapeutic treatments and intervention on the tricuspid valve. New classification scheme should be included in CMR grading scales.

Funding Acknowledgement

Type of funding sources: None. Kaplan Meier curve. Risk stratification

Prognostic value of serum biomarkers in patients with severe tricuspid regurgitation

Background

Significant tricuspid regurgitation (TR) is related to significant morbimortality. Given the lack of strong evidence, optimal timing for intervention remains controversial. Surgery is often performed late mainly because symptoms might go unnoticed until advance stages of the disease. The clinical impact of serum biomarkers evaluation in the serial evaluation of patients with significant TR is unknown.

Purpose

This study was aimed to evaluate the prognostic value of brain natriuretic peptide (BNP) and serum hepatic enzymes assessment in stable patients with significant tricuspid regurgitation

Methods

Consecutive patients in stable clinical status with significant TR (severe, massive or torrential TR) evaluated in the Heart Valve Clinic were included. Patients with previous episodes of heart failure were excluded. BNP levels and liver function enzymes were measured in all patients in their first visit. A combined endpoint of hospital admission due to right heart failure and cardiovascular (CV) mortality was defined.

Results

A total of 163 patients were included (mean age was 75±17 years, 69% females, 93% in NYHA I/II). According to etiology, 14% were primary TR and 86% were functional (49% due to corrected left valve disease and 37% due to tricuspid annulus dilatation). During a median follow up of 28 months (IQR: 15–49 months), n=59 patients (36%) reached the combined endpoint (n=12 patients died). Differences in BNP and liver function enzymes values in patients with or without events are shown in figure 1. BNP values and both cholestasis enzymes (alkaline phosphatase and gamma-glutamyl transferase) were independent predictors of the combined endpoints (Figure 2). In a multivariable Cox analysis (forward selection) in a model including BNP, alkaline phosphatase and gamma-glutamyl transferase, alkaline phosphatase remained as the sole independent predictor of outcome (HR: 1.01, [1.004–1.014], p<0.001).

Conclusion

Serum biomarkers held prognostic value in patients with significant TR. BNP values and colestasis enzymes are predictive of heart failure and CV death in stable patients with TR. Given the low clinical expression of the disease, these serum biomarkers should be considered in the serial evaluation of these patients.

Funding Acknowledgement

Type of funding sources: None. Comparison of serum biomarkersCox regression analysis

Capture of ambient air CO2 from municipal wastewater mineralization by using an ion-exchange membrane

The capture of ambient air CO_2(gas) from synthetic urban wastewater mineralization reaction was studied. An ion exchange membrane was used as sorbent, which adsorbs CO₂ when dry and releases it when wet. The UV/H₂O₂ degradation process was chosen to convert Total Organic Carbon (TOC) to carbon dioxide due to its advantages of convenience and fast kinetics over the conventional biological treatment that is usually used in urban wastewater treatment plants. In the first phase, experiments combining UV-C light and H₂O₂ were carried out to select the optimal values of the following parameters: pH, the dose of H₂O₂ and temperature. In the second stage, the CO_2(gas) emission into the air from the degradation of organic compounds present in wastewater during UV/H₂O₂ process in the absence or presence of ion exchange membranes was evaluated. The effects of parameters such as temperature or air humidity were studied. A qualitative study of desorption was carried out to check the viability of reuse CO₂ captured in the membrane. Finally, a similar CO_2(gas) adsorption capacity after five cycles of adsorption and regeneration of the membranes was observed, being percentage loss of around 4%.

P906 Are all severe Tricuspid Regurgitation the same?

Introduction

Tricuspid regurgitation (TR) importance is growing in the last years. Its presence is associated with a worse prognosis. A new severity classification has been published, adding massive and torrential to the classical TR classification. However, both clinical profile of the patients as well as right chambers morphologic and functional changes have not been described compared to the severe TR patients.

Methods

Consecutive patients undergoing an echocardiographic study in 9 Spanish hospitals within a three-month period with at least moderate TR were prospectively included. All studies with severe TR were selected for analysis. TR assessment was performed as recommended by the European Association of Cardiovascular Imaging. TR severity grades was performed according to Hanh & Zamorano new published classification. Two cohorts were made: patients with severe TR and patients with massive or torrential TR.

Results

A total of 644 patients with severe or bigger TR were analysed. Severe TR was present in 540 (84%), massive was present in 83 (13%) and torrential in 21 (3%) Baseline characteristics of the study population are shown in table 1.

No differences were found in NYHA class or atrial fibrillation incidence between groups. Pacemaker was more frequent in massive/torrential group (30% vs 19%; 0,014).

Patients with massive/torrential TR presented worst RV remodelling data:

-RV was dilated (RV telediastolic basal diameter >42mm) in 84.2% of patients with massive/torrential TR vs 57% of patients with severe TR (p < 0.001).

-Right atrium was bigger in patients with massive/torrential TR (21 ± 0.8 cm2/m2 vs 17.2 ± 0,3 cm2/m2; p < 0.001)

-Tricuspid annulus diameter was bigger between massive/torrential TR patients (26.7 ± 0.6 cm/m2 vs 23.6 ± 0.3 cm/m2; p > 0.001).

No significant differences in prevalence of RV function (TAPSE < 17 mm) were noted 39% vs 33%, p = 0,273.

Conclusions

In this large multicentre cohort of patients, the presence of massive/torrential TR seems to be associated with a differential RV and RA remodelling, reflecting the greater volume overload seen in these patients. Further studies are needed to define prognosis implication of our findings and its role in clinical decision making.

Table 1 Variable Severe (n = 540) Massive/Torrential (n = 104) Body mass index 26,6 (±0,3) 26.4(±0,6) 0.350 Woman 336 (62%) 69 (66%) 0.438 Atrial firilation 298(55%) 61(59%) 0.514 Age (years) 76,5 (±0,5) 77,5(±1,1) 0.209

39 Overview of tricuspid regurgitation (tr). new classification of tr. when severe tr is too severe?

Introduction

Tricuspid regurgitation (TR) importance is growing in the last years. Its presence is associated with a worse prognosis. A new severity classification has been published, adding massive and torrential to the classical TR classification. However, it is not know how many of the patients classified as severe TR, corresponds to the new Torrential or massive classification that for sure will lead to different treatment strategies. Also few published studies have addressed the aetiologies, mechanisms and severity in large cohorts.

Purpose

To evaluate the burden of TR in a large cohort of patients referred for an echocardiography.

Methods

Prospective study where consecutive patients undergoing an echocardiographic study in 10 Spanish hospitals within a three-month period were included. All studies with at least moderate TR were selected for analysis. The evaluation was conduced according to the usual practice of the laboratory. TR assessment was performed as recommended by the European Association of Cardiovascular Imaging. TR was quantified according to Hanh & Zamorano new published classification.

Results

A total of 35088 consecutive echocardiographic studies were performed in the participant hospitals during the recruitment period. TR of at least moderate degree was detected in 2124 studies (6,05%). Mean age was 77,1 years and 62.8% were women.

Mitral or aortic valvulopthy was the most common cause, present in almost half of cases (48.4%). The second cause of TR was idiopathic with 22.2% of cases. Primary TR was found in 7.2% of patients, the most frequent aetiology in these group was cardiac implantable devices with 4.2% of total of TR. Aetiology and severity according to the new classification can be seen in the figures

Atrial fibrillation was present in 47.6% of cases. 56.4% of patients had symptoms at the time of the study (NYHA≥2 at the time of study).

Right ventricle (RV) was dilated (telediastolic basal diameter >42mm) in 39.4% of patients). RV function was impared (TAPSE <17mm) in 30.6% of patients.

Conclusions

In these larger multicentre study, significant TR may is present in up to 6% of the echocardiographic studies and is often symptomatic[m1] . 4,91% of patients had a massive or torrential grade. Most TR are secondary to mitral or aortic valvulopathy. Idiopathic TR has taken the second place.

Abstract 39 Figure. Severity and aetiology of TR

P675Current status of anticoagulation in patients with breast cancer and atrial fibrillation

Aims

Balance between embolic and bleeding risk is challenging in patients with cancer. There is a lack of specific recommendations for the use of antithrombotic therapy in oncologic patients with atrial fibrillation (AF). We compared the embolic and bleeding risk, the preventive management and the incidence of events between patients with and without cancer. We further evaluated the effectiveness and safety of direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) within patients with cancer.

Methods

The AMBER-AF registry is an observational multicentre study that analysed patients with non-valvular AF treated in Oncology and Cardiology Departments in Spain. 1237 female patients with AF were enrolled: 637 with breast cancer and 599 without cancer. Mean follow-up was 3.1 years.

Results

Both groups were similar in age, CHA2DS2-VASc and HASB-LED scores. Lack of guidelines recommended therapies was more frequent among patients with cancer. Compared with patients without cancer, adjusted rates of stroke (hazard ratio [95% confidence interval]) in cancer patients were higher (1.56 [1.04–2.35]), whereas bleeding rates remained similar (1.25 [0.95–1.64]). Within the group of patients with cancer, the use of DOACs vs VKAs did not entail differences in the adjusted rates of stroke (0.91 [0.42–1.99]) or severe bleedings (1.53 [0.93–2.53]).

Follow-up events

Conclusions

Antithrombotic management of AF frequently differs in patients with breast cancer. While breast cancer is associated with a higher risk of incident stroke, bleeding events remained similar. Patients with cancer treated with DOACs experienced similar rates of stroke and bleeding as those with VKAs.

P5569Effective regurgitant oriffice area vs vena contracta method as predictors of outcomes in severe tricuspid regurgitation

Background

There is no gold standard echocardiographic method to evaluate tricuspid regurgitation (TR) severity. ESC guidelines recommend using a combination of several methods. The purpose of this study was to compare the prognostic value of the two most commonly used methods for the evaluation of the TR: Effective regurgitant orifice area (EROA) method and biplane vena contracta (VC) method.

Methods

Consecutive asymptomatic patients with significant TR (moderate to severe or severe by echocardiography) evaluated in the Heart Valve Clinic between 2015–2018 were included.

TR severity was evaluated by a combination of several methods, including EROA method and biplane VC method, using EPIQ system. End-point included cardiovascular mortality, tricuspid valve surgery or heart failure.

Results

A total of 70 patients were included (mean age was 74±8 years, 71% females). According to aetiology, 94% were functional TR (60% due to left valve disease, 27% due to tricuspid annulus dilatation, 13% others). During a median follow up of 18 months [IQR: 4–28], 35% of the patients reached the combined end-point (n=16 developed right heart failure, n=17 underwent tricuspid valve surgery, and n=3 died).

Patients with events showed a larger EROA (0.55 vs 0.40 p: 0.036) but no significance different was found in VC (8.03 vs 7.80 p: 0.27). Among both parameters, the tricuspid EROA was the only prognostic factor of the combined endpoint (EROA, HR 24.22 [1.54–380.86], p=0.023; VC, HR 1.022 [0.882–1.183]. A value of EROA of 0.42 reached the best accuracy to predicted poor outcomes (p<0.01).

Conclusion

Among the two most commonly used methods for the evaluation of the TR, EROA was the only method that obtained prognostic value during follow-up.

P690Incidence of events between vitamin K antagonists and direct oral anticoagulants in patients with cancer

Background

Balance between embolic and bleeding risk is challenging in patients with cancer. There is a lack of specific recommendations for the use of antithrombotic therapy in oncologic patients with atrial fibrillation (AF).

We aimed to evaluate the effectiveness and safety of direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) within patients with breast cancer. We also compared the embolic and bleeding risk, the preventive management and the incidence of events between patients with and without cancer.

Methods

It is an ambispective observational multicentric study that analysed patients with non-valvular AF treated in Oncology and Cardiology Departments in Spain in the period 2011–2018. A total of 1237 female patients with AF were enrolled: 637 with breast cancer and 599 without cancer. The incidence of thromboembolic and major bleeding events according to the antithrombotic strategy with VKAs or DOACs was evaluated in the cohort of 637 patients with cancer. Analysis were conducted using SPSS software V.22.0 and R V.3.5.1, with a two-tailed significance value of 0.05.

Results

Mean follow-up was 3.1 years. Both groups were similar in age, CHA2DS2-VASc and HASB-LED scores. There was no evidence that the incidence of ischemic stroke/systemic embolism differed between patients with cancer treated with AVK and DOAC after CHA2DS2-VASc adjustment: HR 0.91 (95% CI, 0.42–1.99). In addition, no significant differences in the incidence of major bleeding events were found between DOACs and VKA after adjustment for HAS-BLED score: HR 1.53 (95% CI, 0.93–2.53) (Figure 3). Gastrointestinal bleeding was the main source of haemorrhages in both groups (45% of bleedings among patients treated with DOACs and, 37% in VKAs group). Metastatic disease or active chemotherapy were studied as potential covariates but none of them posed any relevant change in the result.

Kaplan-Meier analysis

Conclusions

Cancer patients treated with DOACs did not differ versus those treated with VKAs with regards to stroke or systemic embolism in a model adjusted for CHA2DS2-VASc. Neither significant differences were found for bleeding events in a model adjusted for baseline HASBLED.

Sono-activated persulfate oxidation of diclofenac: Degradation, kinetics, pathway and contribution of the different radicals involved

Degradation of a diclofenac aqueous solution was performed using persulfate anions activated by ultrasound. The objective of this study was to analyze different parameters affecting the diclofenac (DCF) removal reaction by the ultrasonic persulfate (US/PS) process and to evaluate the role played by various intermediate oxidative species such as hydroxyl- and sulfate radicals, superoxide radical anion or singlet oxygen in the removal process as well as to determine a possible reaction pathway. The effects of pH, initial persulfate anion concentration, ultrasonic amplitude and temperature on DCF degradation were examined. Sulfate and hydroxyl radicals were involved in the main reaction pathway of diclofenac. Diclofenac amide and three hydroxy-diclofenac isomers (3´-hydroxy diclofenac, 4´-hydroxy diclofenac and 5-hydroxy diclofenac) were identified as reaction intermediates.

Photocatalytic degradation of aniline using an autonomous rotating drum reactor with both solar and UV-C artificial radiation

The aim of this work was to evaluate the performance of a novel self-autonomous reactor technology (capable of working with solar irradiation and artificial UV light) for water treatment using aniline as model compound. This new reactor design overcomes the problems of the external mass transfer effect and the accessibility to photons occurring in traditional reaction systems. The UV-light source is located inside the rotating quartz drums (where TiO₂ is immobilized), allowing light to easily reach the water and the TiO₂ surface. Several processes (UV, H₂O₂, Solar, TiO₂, Solar/TiO₂, Solar/TiO₂/H₂O₂ and UV/Solar/H₂O₂/TiO₂) were tested. The synergy between Solar/H₂O₂ and Solar/TiO₂ processes was quantified to be 40.3% using the pseudo-first-order degradation rate. The apparent photonic efficiency, ζ, was also determined for evaluating light utilization. For the Solar/TiO₂/H₂O₂ process, the efficiency was found to be practically constant (0.638-0.681%) when the film thickness is in the range of 1.67-3.87 μm. However, the efficiency increases up to 2.67% when artificial UV light was used in combination, confirming the efficient design of this installation. Thus, if needed, lamps can be switched on during cloudy days to improve the degradation rate of aniline and its mineralization. Under the optimal conditions selected for the Solar/TiO₂/H₂O₂ process ([H₂O₂] = 250 mg/L; pH = 4, [TiO₂] = 0.65-1.25 mg/cm²), 89.6% of aniline is degraded in 120 min. If the lamps are switched on, aniline is completely degraded in 10 min, reaching 85% of mineralization in 120 min. TiO₂ was re-used during 5 reaction cycles without apparent loss in activity (<2%). Quantification of hydroxyl radicals and dissolved oxygen allows a chemical-based explanation of the process. Finally, the UV/Solar/TiO₂/H₂O₂ process was found to have lower operation costs than other systems described in literature (0.67 €/m³).

Study of the intensification of solar photo-Fenton degradation of carbamazepine with ferrioxalate complexes and ultrasound

The intensification of the solar photo-Fenton system with ferrioxalate photoactive complexes and ultrasound applied to the mineralization of 15mg/L carbamazepine aqueous solution (CBZ) was evaluated. The experiments were carried out in a solar compound parabolic collector (CPC) pilot plant reactor coupled to an ultrasonic processor. The dynamic behavior of hydroxyl radicals generated under the different studied reaction systems was discussed. The initial concentrations of hydrogen peroxide and ferrous/oxalic acid and pH were found to be the most significant variables (32.79%, 25.98% and 26.04%, respectively). Under the selected optimal conditions ([H₂O₂]₀=150mg/L; [Fe²⁺]₀=2.5mg/L/[(COOH)₂]₀=12.1mg/L; pH=5) CBZ was fully degraded after 5min and 80% of TOC was removed using a solar photo-Fenton system intensified with ferrioxalate (SPFF). However, no improvement in the mineralization using SPFF process combined with ultrasound was observed. More mild pH conditions could be used in the SPFF system if compared to the traditional photo-Fenton (pH 3) acidic systems. Finally, a possible reaction pathway for the mineralization of CBZ by the SPFF system was proposed and therein discussed.

Mineralization of aniline using hydroxyl/sulfate radical-based technology in a waterfall reactor

The aim of this work is to study the applicability of a UV/H₂O₂ process intensified with persulfate (PS) as a source of SO₄^- radicals to efficiently mineralize a synthetic effluent containing aniline in a glass reactor arranged in a cascade configuration. pH conditions were studied and the concentration of PS was optimized. The synergism for aniline mineralization between the UV/H₂O₂ process and the combined UV/H₂O₂/PS process was quantified in 10.1%. Aniline degradation reached 100% under the UV/H2O2/PS process after 20 min. Its mineralization is favored under acidic conditions and with the presence of persulfate (optimal conditions: 49% in 90 min; pH = 4; [PS] = 250 ppm). On the contrary, the worst conditions were found at pH = 11, since hydrogen peroxide decomposes and carbonates were formed increasing the scavenging effect. The different mechanisms involved (formulated from intermediates identified by mass spectrometry) confirm these results. Aniline was found to follow a degradation pathway where phenol is the main intermediate. The presence of sulfate radicals increases phenol degradation rate leading to a higher mineralization extent. Benzoquinone was identified as the main aromatic oxidation product of phenol, whereas succinic, 4-oxo-pentanoic, fumaric and oxalic acids were detected as aliphatic oxidation products for both UV/H2O2 and UV/H2O2/PS oxidation processes.

Dynamic behavior of hydroxyl radical in sono-photo-Fenton mineralization of synthetic municipal wastewater effluent containing antipyrine

The aim of this study was to examine the kinetics of the different mechanisms (radical pathway, photolysis, molecular reaction with H₂O₂ and reaction with ultrasonically generated oxidative species) involved in the homogeneous sono-photoFenton (US/UV/H₂O₂/Fe) mineralization of antipyrine present in a synthetic municipal wastewater effluent (ASMWE). The dynamic behavior of hydroxyl (HO) radical generation and consumption in mineralization reaction under different systems was investigated by measuring hydroxyl radical concentration during the reaction. The overall mineralization process was optimized using a Central-Composite Experimental Design (CCED) with four variables (initial concentrations of H₂O₂ and Fe(II), amplitude and pulse length). The response functions (pseudo-first order mineralization kinetic rate constants) were fitted using neural networks (NNs). Under the optimal conditions ([H₂O₂]_o=500mgL^-1, [Fe(II)]_o=27mgL^-1, Amplitude (%)=20andPulse length=1), the TOC removal was 79% in 50min. The radical reaction in the bulk solution was found be the primary mineralization pathway (94.8%), followed by photolysis (3.65%), direct reaction with H₂O₂ (0.86%), and reaction by ultrasonically generated oxidative species (0.64%). The role of the Fe catalyst on the radical reaction and the presence of refractory intermediates towards hydroxyl radical were also studied.

Antipyrine removal by TiO2 photocatalysis based on spinning disc reactor technology

The photo-degradation of the emerging contaminant antipyrine (AP) was studied and optimized in a novel photocatalytic spinning disc reactor (SDR). A heterogeneous process (UV/H₂O₂/TiO₂) was used. TiO₂ was immobilized on the surface of a glass disc using a sol-gel method. A factorial design of experiments followed by a Neural Networks fitting allowed the optimal conditions to be determined for treating 50 mg/L of AP. Under these conditions (pH = 4; [H₂O₂]₀ = 1500 mg/L; disc speed = 500 rpm; flowrate = 25 mL/s), AP was completely degraded in 120 min and regeneration of the disc allowed 10 cycles with no loss in efficiency. The value of the apparent volumetric rate constant was found to be 6.9·10^-4 s^-1 with no apparent mass transfer limitation. Based on the main intermediates identified, a mechanism is proposed for antipyrine photodegradation: Firstly, cleavage of the NN bond of penta-heterocycle leads to the formation of two aromatic acids and N-phenylpropanamide. An attack to the CN bond in the latter compound produces benzenamine. Finally, the phenyl ring of the aromatic intermediates are opened and molecular organic acids are formed.

Sono-photo-degradation of carbamazepine in a thin falling film reactor: Operation costs in pilot plant

The photo-Fenton degradation of carbamazepine (CBZ) assisted with ultrasound radiation (US/UV/H₂O₂/Fe) was tested in a lab thin film reactor allowing high TOC removals (89% in 35min). The synergism between the UV process and the sonolytic one was quantified as 55.2%. To test the applicability of this reactor for industrial purposes, the sono-photo-degradation of CBZ was also tested in a thin film pilot plant reactor and compared with a 28L UV-C conventional pilot plant and with a solar Collector Parabolic Compound (CPC). At a pilot plant scale, a US/UV/H₂O₂/Fe process reaching 60% of mineralization would cost 2.1 and 3.8€/m³ for the conventional and thin film plant respectively. The use of ultrasound (US) produces an extra generation of hydroxyl radicals, thus increasing the mineralization rate. In the solar process, electric consumption accounts for a maximum of 33% of total costs. Thus, for a TOC removal of 80%, the cost of this treatment is about 1.36€/m³. However, the efficiency of the solar installation decreases in cloudy days and cannot be used during night, so that a limited flow rate can be treated.

Application of activated persulfate for removal of intermediates from antipyrine wastewater degradation refractory towards hydroxyl radical

Complete mineralisation of reaction intermediates refractory towards hydroxyl radical, generated from a previous ineffective degradation of urban wastewater containing antipyrine by HO-mediated sono-photo-Fenton reaction, has been attained using persulfate anions simultaneously activated by heat energy (thermally, ultrasound) and UV-C light. The SO4(-)-based mineralisation process enables another reaction pathway generating more easy degradable derivatives. The influences of the initial concentration of persulfate, ultrasound amplitude, temperature and the reaction time in the previous HO-based previous oxidation on the mineralisation degree were studied by using a Central-Composite Experimental Design. Under optimal conditions ([S2O8(2-)]o=1200mgL(-1), temperature=50°C, amplitude=10%, pH 2.8, HO-based reaction time=25min) practically complete degradation was achieved in approximately 120min. The contribution of HO and SO4(-) radicals in this system was also evaluated. The presence of chloride ion in urban wastewater can benefit the oxidation of acetate by sulfate radical. Results demonstrated that this activated persulfate-based oxidation system is a potential alternative to degrade intermediate compounds, which are refractory against hydroxyl radicals, generated in Advanced Oxidation Processes used to treat wastewater containing emerging contaminants such as antipyrine.

Mineralization of wastewater from the pharmaceutical industry containing chloride ions by UV photolysis of H2O2/Fe(II) and ultrasonic irradiation

The mineralization of pharmaceutical wastewater containing chloride ions using a UV/H2O2/Fe(II) process was studied. The addition of Fe(II) to the UV/H2O2 system did not improve the degradation efficiency due to inhibition of the photo-Fenton reaction, at acid pH, in the presence of chloride ions in these wastewaters. The increase of pH from 2 to 7 increased the degree of mineralization under UV photolysis of H2O2 because more HO radicals are available by HOCl dissociation reaction. Under the selected operation conditions ([H2O2]o = 11,500 ppm, [Fe(II)] = 0 ppm, [TOC]o = 125 ppm and pH = 7), 100% of TOC removal was attained in 120 min. A significant synergistic effect of combining photolysis (UV/H2O2) and sonolysis was observed. Sonophotolysis (UV/H2O2/ultrasound) technique significantly increased the degree of mineralization (100% TOC removal in 90 min using 6500 ppm H2O2) when compared with each individual process. Sonochemical reaction was favored by the presence of chloride ions since the concentration of contaminants at the gas-liquid interface increased. Free radicals reaction was the controlling mechanism in the UV/H2O2/ultrasound system. HO radicals were the main oxidative intermediate species in the process, although hydroperoxyl radicals (HO2) also played a role. The contribution of thermal-pyrolytic reaction (in gas-phase) to sonophotolysis process was negligible.

Solar photo-Fenton mineralization of antipyrine in aqueous solution

The mineralization of an aqueous solution of antipyrine (C11H12N2O), an emerging contaminant, using a solar photocatalytic oxidation process assisted with ferrioxalate was evaluated in a compound parabolic collector (CPC) pilot plant. Under the selected operating conditions ([H2O2] = 250 ppm, [Fe] = 14 ppm, pH = 2.7, and [(COOH)2·2H2O] = 80 ppm), 60% of TOC is removed just 5 min after treating an aqueous solution containing 50 ppm of antipyrine. The addition of oxalic acid up to a maximum concentration of 80 ppm significantly increases the mineralization rate during the first 15 min of the reaction. The synergism between the solar and dark H2O2/ferrioxalate process was quantified at 79%, calculated from the pseudo first-order mineralization rate constants. The operational costs due to the consumption of electrical energy, reagents and catalysts were calculated from the optimal conditions and compared with a novel sono-photocatalytic process using artificial UV-light. The results showed that the ferrioxalate-assisted solar photo-Fenton process was economically feasible, being able to achieve up to 60% mineralization with a total cost of 4.5 cent €/g TOC removed (1.1 €/m(3)).

Optimization of pharmaceutical wastewater treatment by solar/ferrioxalate photo-catalysis

The degradation of a pharmaceutical wastewater using a ferrioxalate-assisted solar/photo-Fenton system has been studied. The photochemical reaction was carried out in a pilot plant consisting of a compound parabolic collector (CPC) solar reactor. An optimization study was performed combining a multivariate experimental design and Neuronal Networks that included the following variables: initial concentrations of H2O2, catalyst Fe (II) and oxalic acid (H2C2O4), temperature and solar power. Under optimal conditions, 84% TOC (Total Organic Carbon) removal was achieved in 115 min. Oxalic acid had a positive effect on mineralization when solar power was above 30 W m(-2). The minimum amount of H2O2 to degrade 1 mol of TOC was found to be 3.57 mol. Both the H2O2 conversion efficiency and the degree of mineralization were highest when the oxalic/Fe(II) initial molar relation was close to 3. HO radicals were the main oxidative intermediate species in the process, although hydroperoxyl radicals (HO(2)(·)) also played a role.

Homogeneous sonophotolysis of food processing industry wastewater: Study of synergistic effects, mineralization and toxicity removal

The mineralization of industrial wastewater coming from food industry using an emerging homogeneous sonophotolytic oxidation process was evaluated as an alternative to or a rapid pretreatment step for conventional anaerobic digestion with the aim of considerably reducing the total treatment time. At the selected operation conditions ([H(2)O(2)]=11,750ppm, pH=8, amplitude=50%, pulse length (cycles)=1), 60% of TOC is removed after 60min and 98% after 180min when treating an industrial effluent with 2114ppm of total organic carbon (TOC). This process removed completely the toxicity generated during storing or due to intermediate compounds. An important synergistic effect between sonolysis and photolysis (H(2)O(2)/UV) was observed. Thus the sonophotolysis (ultrasound/H(2)O(2)/UV) technique significantly increases TOC removal when compared with each individual process. Finally, a preliminary economical analysis confirms that the sono-photolysis with H(2)O(2) and pretreated water is a profitable system when compared with the same process without using ultrasound waves and with no pretreatment.

Photocatalytic treatment of an industrial effluent using artificial and solar UV radiation: an operational cost study on a pilot plant scale

The aim of this work was to study the operation costs of treating a real effluent from an integrated gasification combined cycle (IGCC) power station located in Spain. The study compares different homogeneous photocatalytic processes on a pilot plant scale using different types of radiation (artificial UV or solar UV with a compound parabolic collector). The efficiency of the processes was evaluated by an analysis of the total organic carbon (TOC) removed. The following processes were considered in the study: (i) a photo-Fenton process at an artificial UV pilot plant (with the initial addition of H(2)O(2)), (ii) a modified photo-Fenton process with continuous addition of H(2)O(2) and O(2) to the system and (iii) a ferrioxalate-assisted solar photo-Fenton process at a compound parabolic collector (CPC) pilot plant. The efficiency of these processes in degrading pollutants has been studied previously, and the results obtained in each of those studies have been published elsewhere. The operational costs due to the consumption of electrical energy, reagents and catalysts were calculated from the optimal conditions of each process. The results showed that the solar photo-Fenton system was economically feasible, being able to achieve up to 75% mineralization with a total cost of 6 €/m(3), which can be reduced to 3.6 €/m(3) by subtracting the electrical costs because the IGCC plant is self-sufficient in terms of energy.

Optimization of the mineralization of a mixture of phenolic pollutants under a ferrioxalate-induced solar photo-Fenton process

The mineralization of solutions containing a mixture of three phenolic compounds, gallic, p-coumaric and protocatechuic acids, in a ferrioxalate-induced solar photo-Fenton process was investigated. The reactions were carried out in a pilot plant consisting of a compound parabolic collector (CPC) solar reactor. An optimization study was performed combining a multivariate experimental design and neuronal networks that included the following variables: pH, temperature, solar power, air flow and initial concentrations of H(2)O(2), Fe(II) and oxalic acid. Under optimal conditions, total elimination of the original compounds and 94% TOC removal of the mixture were achieved in 5 and 194 min, respectively. pH and initial concentrations of H(2)O(2) and Fe(II) were the most significant factors affecting the mixture mineralization. The molar correlation between consumed hydrogen peroxide and removed TOC was always between 1 and 3. A detailed analysis of the reaction was presented. The values of the pseudo-first-order mineralization kinetic rate constant, k(TOC), increased as initial Fe(II) and H(2)O(2) concentrations and temperature increased. The optimum pH value also slightly increased with greater Fe(II) and hydrogen peroxide concentrations but decreased when temperature increased. OH and O(2)(-) radicals were the main oxidative intermediate species in the process, although singlet oxygen ((1)O(2)) also played a role in the mineralization reaction.

Mineralization of integrated gasification combined-cycle power-station wastewater effluent by a photo-Fenton process

The aim of this work was to study the mineralization of wastewater effluent from an integrated-gasification combined-cycle (IGCC) power station sited in Spain to meet the requirements of future environmental legislation. This study was done in a pilot plant using a homogeneous photo-Fenton oxidation process with continuous addition of H(2)O(2) and air to the system. The mineralization process was found to follow pseudo-first-order kinetics. Experimental kinetic constants were fitted using neural networks (NNs). The NNs model reproduced the experimental data to within a 90% confidence level and allowed the simulation of the process for any values of the parameters within the experimental range studied. At the optimum conditions (H(2)O(2) flow rate=120 mL/h, [Fe(II)]=7.6 mg/L, pH=3.75 and air flow rate=1 m(3)/h), a 90% mineralization was achieved in 150 min. Determination of the hydrogen peroxide consumed and remaining in the water revealed that 1.2 mol of H(2)O(2) was consumed per each mol of total organic carbon removed from solution. This result confirmed that an excess of dissolved H(2)O(2) was needed to achieve high mineralization rates, so continuous addition of peroxide is recommended for industrial application of this process. Air flow slightly improved the mineralization rate due to the formation of peroxo-organic radicals which enhanced the oxidation process.

Photocatalytic treatment of IGCC power station effluents in a UV-pilot plant

The aim of this work is to improve the quality of water effluents coming from an Integrated Gasification Combined Cycle (IGCC) power station to meet with future environmental legislation. This study has been made using an homogeneous photocatalytic oxidation process (UV/Fe(II)/H(2)O(2)) in a pilot plant. The efficiency of the process was determined from the analysis of the following parameters: cyanides, formates and TOC content. In the first stage, a factorial experimental design allowed to determine the influence of operation variables (initial concentration of H(2)O(2) and Fe(II), pH and temperature) on the degradation kinetics. pH was always kept in a value >9.5 during cyanides destruction to avoid gaseous HCN formation and lowered later to enhance formates degradation. Experimental kinetic constants were fitted using neural networks (NNs). Under the optimum conditions ([H(2)O(2)]=1700 ppm, [Fe(II)]=2 ppm, pH 2 after cyanides destruction, and T=30 degrees C), it is possible to degrade 100% of cyanides in 15 min and 76% of formates in 120 min. The use of an homogeneous process with UV light can offer an economical and practical alternative to heterogeneous photocatalysis for the destruction of environmental pollutants present in thermoelectric power stations effluents, since it can treat very high flowrates using a lower H(2)O(2) concentration. Furthermore, it does not require additional operations to recover the solid catalyst and regenerate it due to deactivation as occurs in heterogeneous catalysis.

Treatment of IGCC power station effluents by physico-chemical and advanced oxidation processes

The aim of this work was to improve the quality of aqueous effluents coming from the Gasification Unit in an Integrated Gasification Combined Cycle (IGCC) Thermoelectric Power Station, with the purpose of fulfilling the future more demanding normative. To this end, an integral wastewater treatment including coagulation, flocculation, neutralization, photocatalytic oxidation, and ion-exchange has been studied. A final scheme has been proposed to remove pollutants. All the parameters of the treated wastewater are below pouring specifications. In the first stage, the wastewater was treated with CaCl2 (optimal dose=11 g CaCl2/g F-) as coagulant and a commercial anionic polyelectrolyte (optimal dose=0.02 g/g F-) as flocculant to remove fluoride ions (99%) and suspended solids (92%). The water was then neutralized, improving the degree of transmission of ultraviolet light, allowing the faster photo-degradation of pollutants. The photochemical study included different systems (H2O2, UV/H2O2, Fenton, Fenton-like, UV/Fenton, UV/Fenton-like and UV/H2O2/O2). In the Fenton-like system, the influence of two parameters (initial concentration of H2O2 and amount of Cu(II)) on the degradation of cyanide and formate (taken as the reference of the process) was studied. Experimental results were fit using neural networks (NNs). Results showed that the photocatalytic process was effective for total cyanide destruction after 60 min, while 180 min was needed to remove 80% of formates. However, a more simple system with UV/H2O2/O2 yields similar results and is preferred for industrial application due to fewer complications. Finally, an ion-exchange process with Amberlite IRA-420 was proposed to remove the excess of chlorides added as a consequence of the initial coagulation process.

Solar TiO2-assisted photocatalytic degradation of IGCC power station effluents using a Fresnel lens

The heterogeneous TiO2 assisted photocatalytic degradation of wastewater from a thermoelectric power station under concentrated solar light irradiation using a Fresnel lens has been studied. The efficiency of photocatalytic degradation was determined from the analysis of cyanide and formate removal. Firstly, the influence of the initial concentration of H2O2 and TiO2 on the degradation kinetics of cyanides and formates was studied based on a factorial experimental design. Experimental kinetic constants were fitted using neural networks. Results showed that the photocatalytic process was effective for cyanides destruction (mainly following a molecular mechanism), whereas most of formates (degraded mainly via a radical path) remained unaffected. Finally, to improve formates degradation, the effect of lowering pH on their degradation rate was evaluated after complete cyanide destruction. The photooxidation efficiency of formates reaches a maximum at pH around 5-6. Above pH 6, formate anion is subjected to electrostatic repulsion with the negative surface of TiO2. At pH<4.5, formate adsorption and photon absorption are reduced due to some catalyst agglomeration.

Photocatalytic degradation of pollutants from Elcogas IGCC power station effluents

The aim of this work is to improve the quality of water effluents coming from Elcogas IGCC power station (Puertollano, Spain) with the purpose of fulfilling future more demanding normative, using heterogeneous photocatalytic oxidation processes (UV/H(2)O(2)/TiO(2) or ZnO). The efficiency of photocatalytic degradation for the different catalysts (TiO(2) and ZnO) was determined from the analysis of the following parameters: cyanides, formates and ammonia content. In a first stage, the influence of two parameters (initial concentration of H(2)O(2) and amount of catalyst) on the degradation kinetics of cyanides and formates was studied based on a factorial experimental design. pH was always kept in a value >9.5 to avoid gaseous HCN formation. The degradation of cyanides and formates was found to follow pseudo-first order kinetics. Experimental kinetic constants were fitted using neural networks (NNs). The mathematical model reproduces experimental data within 90% of confidence and allows the simulation of the process for any value of parameters in the experimental range studied. Moreover, a measure of the saliency of the input variables was made based upon the connection weights of the neural networks, allowing the analysis of the relative relevance of each variable with respect to the others. Results showed that the photocatalytic process was effective, being the degradation rate of cyanides about five times higher when compared to removal of formates. Finally, the effect of lowering pH on the degradation of formates was evaluated after complete cyanides destruction was reached (10 min of reaction). Under the optimum conditions (pH 5.2, [H(2)O(2)]=40 g/l; [TiO(2)]=2g/l), 100% of cyanides and 92% of initial NH(3) concentration are degraded after 10 min, whereas 35 min are needed to degrade 98% of formates.

Solar photocatalytic degradation of reactive blue 4 using a Fresnel lens

The heterogeneous photocatalytic degradation of reactive blue 4 dye (RB4) solutions under Fenton reagent and TiO(2) assisted by concentrated solar light irradiation using a Fresnel lens has been studied. Multivariate experimental design was applied to study the kinetic process. The efficiency of photocatalytic degradation was determined from the analysis of color and total organic carbon (TOC) removal. Factorial experimental design allowed to determine the influence of four parameters (pH and initial concentrations of TiO(2), Fe(II) and H(2)O(2)) on the value of the decoloration kinetic rate constant. Experimental data were fitted using neural networks (NNs). The mathematical model reproduces experimental data within 86% of confidence and allows the simulation of the process for any value of parameters in the experimental range studied. Also, a measure of the saliency of the input variables was made based upon the connection weights of the neural networks, allowing the analysis of the relative relevance of each variable with respect to the others. Results showed that acidic pHs (pH=3.6) are preferred for the complete dye decoloration. The optimum catalyst concentration is 1.2g TiO(2)/l. The use of a low cost catalyst and its activation using a Fresnel lens to concentrate solar energy significantly accelerates the degradation process when compared with direct solar radiation alone and can offer an economical and practical alternative for the destruction of environmental organic compounds.

Fresnel lens to concentrate solar energy for the photocatalytic decoloration and mineralization of orange II in aqueous solution

The decoloration and mineralization of the azo dye orange II under conditions of artificial ultraviolet light and solar energy concentrated by a Fresnel lens in the presence of hydrogen peroxide and TiO(2)-P25 was studied. A comparative study to demonstrate the viability of this solar installation was done to establish if the concentration reached in the focus of the Fresnel lens was enough to improve the photocatalytic degradation reaction. The degradation efficiency was higher when the photolysis was carried out under concentrated solar energy irradiation as compared to UV light source in the presence of an electron acceptor such us H(2)O(2) and the catalyst TiO(2). The effect of hydrogen peroxide, pH and catalyst concentration was also determined. The increase of H(2)O(2) concentration until a critical value (14.7 mM) increased both the solar and artificial UV oxidation reaction rate by generating hydroxyl radicals and inhibiting the (e(-)/h(+)) pair recombination, but the excess of hydrogen peroxide decreases the oxidation rate acting as a radical or hole scavenger and reacting with TiO(2) to form peroxo-compounds, contributing to the inhibition of the reaction. The use of the response surface methodology allowed to fit the optimal values of the parameters pH and catalyst concentration leading to the total solar degradation of orange II. The optimal pH range was 4.5-5.5 close to the zero point charge of TiO(2) depending on surface charge of catalyst and dye ionization state. Dosage of catalyst higher than 1.1 gl(-1) decreases the degradation efficiency due to a decrease of light penetration.

Fenton's oxidation of food processing wastewater components. Kinetic modeling of protocatechuic acid degradation

The oxidation of protocatechuic acid (PA), a typical phenol-type compound present in food processing wastewater, has been carried out by means of Fenton's reagent. Both the H2O2 and Fe(II) initial concentrations increase the PA degradation rate. Temperature also enhances the PA conversion when raised from 283 to 313 K, a further increase to 323 K results in a lower PA removal. Increasing the PA initial concentration leads to a decrease of conversion values but an opposite effect in terms of removal rate. pH values in the range 3-4 resulted in the total inhibition of the oxidation process. Similar PA depletion rates were experienced regardless of the oxidation state of the catalyst (ferrous or ferric iron). Additionally, an attempt based on the classic Fenton's chemistry plus some other stages accounting for the Fe(II) regeneration from Fe(III) and the inefficient H2O2 decomposition was conducted to model the process.

Photo-Fenton-assisted ozonation of p-Coumaric acid in aqueous solution

The degradation of p-Coumaric acid present in olive oil mill wastewater was investigated as a pretreatment stage to obtain more easily biodegradable molecules, with lower toxicity that facilitates subsequent anaerobic digestion. Thus, photo-Fenton-assisted ozonation has been studied and compared with ozonation at alkaline pH and conventional single ultraviolet (UV) and acid ozonation treatments. In the combined process, the overall kinetic rate constant was split into various components: direct oxidation by UV light, direct oxidation by ozone and oxidation by hydroxyl radicals. Molecular and/or radical ozone reaction was studied by conducting the reaction in the presence and absence of tert-butylalcohol at pHs 2, 7 and 9. Ozone oxidation rate increases with pH or by the addition of Fenton reagent and/or UV radiation due to generation of hydroxyl radicals, *OH. Hydrogen peroxide and ferrous ion play a double role during oxidation since at low concentrations they act as initiators of hydroxyl radicals but at high concentrations they act as radical scavengers. Finally, the additional levels of degradation by formation of hydroxyl radicals have been quantified in comparison to the conventional single processes and an equation is proposed for the reaction rate as a function of studied operating variables.

Modelling soot and SOF emissions from a diesel engine

Modelling of soot and SOF emissions from a typical European turbocharged diesel engine has been made. The model consists of a detailed kinetic mechanism with 472 reactions (120 chemical species) and data from the thermodynamic diagnostic procedure of the combustion process of the engine. The forward kinetic constants were obtained from literature and the background constants from a self-developed non-linear fitting routine based on the Marquardt algorithm. The dilution and mixing processes inside the engine are represented by a simple Wiebe function. The system of ordinary differential equations is solved with the Rosenbrock method for rigid systems and using the interpolating Lagrange polynomials to calculate the heat capacity of each species at the corresponding temperature. The kinetic model has been implemented in Digital Visual Fortran 6.0. The model has been executed for five different fuels and three mixtures of biodiesel and reference diesel operating under three diverse conditions from the European transient urban/extraurban Certification Cycle and the results of soot and SOF predicted are compared with experimental data.