Peroxydisulfate activation by CuO pellets in a fixed-bed column, operating mode and assessments for antibiotics degradation and urban wastewater disinfection

A fixed-bed column packed with copper oxide pellets (FBC-CuO) combined with peroxydisulfate (PDS) as a primary oxidant was assessed as an option for simultaneously wastewater decontamination (antibiotics) and disinfection (bacteria, viruses, and protozoa). Preliminary to these experiments, phenol was used as the target molecule to investigate the working mode of FBC-CuO under various operating conditions, such as varying flow rates, initial persulfate, and phenol concentrations. Then, the removal of a mix of five representative antibiotics (amoxicillin (AMX), cefalexin (CFX), ofloxacin (OFL), sulfamethoxazole (SMX), and clarithromycin (CLA)) in secondary treated urban wastewater (STWW) was evaluated. AMX, CFX, and OFL were effectively removed by simply flowing through the FBC-CuO, and the addition of PDS (500 µM) systematically enhanced the degradation of all targeted antibiotics, which is also the necessary condition for the removal of SMX and CLA. Urban wastewater disinfection was evaluated by monitoring targeted pathogens originally in the STWW. A significant reduction of Escherichia coli, Enterococcus, F-specific RNA bacteriophages was observed after the treatment by FBC-CuO with 500 µM PDS. X-ray diffraction measurement and scanning electron microscopy performed on CuO pellets before and after treatment confirmed that the structure of the catalyst was preserved without any phase segregation. Finally, quantification of Cu(II) at the outlet of FBC-CuO indicate a non-negligible but limited released. All these results underline the potential of the FBC-CuO combined with PDS at the field scale for the degradation of micropollutants and inactivation of pathogens in wastewater.

Copper oxide/peroxydisulfate system for urban wastewater disinfection: Performances, reactive species, and antibiotic resistance genes removal

In this study, copper oxide (CuO) catalyzed peroxydisulfate (PDS) system was investigated for the inactivation of a broad range of pathogenic microorganisms from urban wastewater. Complete inactivation of Escherichia coli, Enterococcus, F-specific RNA bacteriophages from secondary treated wastewater was achieved after a short time (15-30 min) treatment with CuO (10 g/L)/PDS (1 mM) system, but spores of sulfite-reducing bacteria took 120 min. No bacterial regrowth occurred during storage after treatment. Significant reduction of the pathogens was explained by the generation of the highly selective Cu(III) oxidant, as the predominant reactive species, which could quickly oxidize guanine through a one-electron oxidation pathway. Additionally, the potential of the CuO (10 g/L)/PDS (1 mM) system to inactivate antibiotic-resistant bacteria and antibiotic resistance genes (ARB&Gs) was explored. Sulfamethoxazole-resistant E. coli was used as the model ARB and a 3.2 log of reduction was observed after 10 min of treatment. A considerable reduction (0.7-2.3 log) of selected ARGs including blaTEM, qnrS, emrB, sul1, and genes related to the dissemination of antibiotic resistance, including the Class 1 integron-integrase (intI1), and the insertion sequence (IS613) was achieved after 60 min treatment. All these findings indicated the promising applicability of the CuO/PDS system as a disinfection technology for wastewater reuse in agriculture.

Persistence and adherence to parenteral osteoporosis therapies: a systematic review

Osteoporosis is a chronic disease of low bone mass and fragility. Treatment is frequently compromised by suboptimal medication compliance causing increased morbidity. This review investigates adherence and persistence to parenteral osteoporosis therapies. Findings reveal parenteral medications requiring reduced dosing frequency have higher compliance than oral therapies. This systematic review examines real-world adherence to parenteral osteoporosis therapies. We searched PubMed, Medline, and EMBASE databases for English language observational studies that examined patient adherence and/or persistence to parenteral osteoporosis treatments (teriparatide sc, ibandronate iv, zoledronic acid iv, and denosumab sc) in adults with osteoporosis published up to September 2018. Studies with only self-reported adherence or persistence data and those with less than 20 patients were excluded. Quality assessment of included studies was completed using the Newcastle-Ottawa quality assessment scale (NOS). We identified 40 eligible studies. Teriparatide was examined in 29 studies, with persistence rates of 10-87% (median 55%) at 1 year and 10-69% (median 29.5%) at 2 years, and adherence rates of 21-89% (median 53%) at 1 year and 37-68% (median 40%) at 2 years. Ten studies of zoledronic acid reported persistence rates of 34-73% (median 42%) for second dose and 20-54% (median 35.8%) for third dose. Ten studies of ibandronate adherence reported and 2-year persistence rates of 31-58% (median 47.5%) in 1 year and 13-35% (median 25%) at 2 years, and adherence rates of 21-72% (median 47.3%) and 15-58% (median 36.5%) respectively. Denosumab was reported in 19 studies, with second (1 year) and fourth (2 year) dose persistence rates of 61-100% (median 81%) and 36-99% (median 45.5%). There is substantial heterogeneity in reports of persistence and adherence rates with parenteral osteoporosis therapies. Most of the published data are from short-term studies and evaluations of long-term adherence and persistence with parenteral therapies for osteoporosis are needed.

Sol–gel synthesis and solar photocatalytic activity of Ca-alloyed ZnO nanoparticles elaborated using different precursors

Ca-alloyed ZnO nanoparticles elaborated using different calcium precursors (CaSO₄, CaCl₂, Ca(NO₃)₂ and CaCO₃) at different [Ca]/[Zn] ratios (0, 1, 5, 10, 15 and 20%) have been prepared by a sol–gel method followed by supercritical drying and annealing at 300 °C. The synthesized samples have been characterized by a number of techniques including Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), Raman Spectroscopy and Electron Paramagnetic Resonance (EPR). SEM and TEM images reveal that the nanoparticles have a quasi-spherical shape with a grain size between 20 and 40 nm. The EDS results on chemical elementary compositions show that the Ca-alloyed ZnO with a CaCO₃ precursor and [Ca]/[Zn] ratios of 5 and 10% are quasi-stoichiometric. The XRD results indicate that all the elaborated nanoparticles have a hexagonal wurtzite structure. Using Raman Spectroscopy a supplementary vibrational mode is detected in the case of CaSO₄, CaCO₃ and Ca(NO₃)₂ precursors. The intrinsic defect centers and defect number have been studied using EPR. Two intrinsic defects with different g factors are identified by EPR for which the spectral intensities change with calcium precursors. Furthermore, EPR reveals a correlation between the defect number and photocatalytic efficiency. The photocatalytic efficiency of the nanoparticles elaborated with different precursors and compositions has been studied for the solar photocatalytic degradation of pyrimethanil, using a solar simulator. The results show that the nanoparticles of Ca-alloyed ZnO elaborated with a CaCO₃ precursor give promising results and enhance the photocatalytic efficiency in the solar field.

Schematic representation of core–shell intrinsic defects in Zn_1−xCa_xO nanoparticles observed by EPR spectroscopy.

In situ synthesis of gold nanoparticles in polymer films under concentrated sunlight: control of nanoparticle size and shape with solar flux

We proposed a one step, green and efficient approach to synthesize plasmonic nanocomposites over large surfaces and with controlled morphologies.

Combining micelle-clay sorption to solar photo-Fenton processes for domestic wastewater treatment

A tertiary treatment of effluent from a biological domestic wastewater treatment plant was tested by combining filtration and solar photocatalysis. Adsorption was carried out by a sequence of two column filters, the first one filled with granular activated carbon (GAC) and the second one with granulated nano-composite of micelle-montmorillonite mixed with sand (20:100, w/w). The applied solar advanced oxidation process was homogeneous photo-Fenton photocatalysis using peroxymonosulfate (PMS) as oxidant agent. This combination of simple, robust, and low-cost technologies aimed to ensure water disinfection and emerging contaminants (ECs, mainly pharmaceuticals) removal. The filtration step showed good performances in removing dissolved organic matter and practically removing all bacteria such as Escherichia coli and Enterococcus faecalis from the secondary treated water. Solar advanced oxidation processes were efficient in elimination of trace levels of ECs. The final effluent presented an improved sanitary level with acceptable chemical and biological characteristics for irrigation.

Use of solar advanced oxidation processes for wastewater treatment: Follow-up on degradation products, acute toxicity, genotoxicity and estrogenicity

Wastewater tertiary treatment by advanced oxidation processes is thought to produce a treated effluent with lower toxicity than the initial influent. Here we performed tertiary treatment of a secondary effluent collected from a Waste Water Treatment Plant via homogeneous (solar/HSO5(-)/Fe(2+)) and heterogeneous (solar/TiO2) solar advanced oxidation aiming at the assessment of their effectiveness in terms of contaminants' and toxicity abatement in a plain solar reactor. A total of 53 organic contaminants were qualitatively identified by liquid chromatography coupled to high-resolution mass spectrometry after solid phase extraction. Solar advanced oxidation totally or partially removed the major part of contaminants detected within 4.5 h. Standard toxicity tests were performed using Vibrio fischeri, Daphnia magna, Pseudokirchneriella subcapitata and Brachionus calyciflorus organisms to evaluate acute and chronic toxicity in the secondary or tertiary effluents, and the EC50% was calculated. Estrogenic and genotoxic tests were carried out in an attempt to obtain an even sharper evaluation of potential hazardous effects due to micropollutants or their degradation by-products in wastewater. Genotoxic effects were not detected in effluent before or after treatment. However, we observed relevant estrogenic activity due to the high sensitivity of the HELN ERα cell line.

Biosensor-based real-time monitoring of paracetamol photocatalytic degradation

This paper presents for the first time the integration of a biosensor for the on-line, real-time monitoring of a photocatalytic degradation process. Paracetamol was used as a model molecule due to its wide use and occurrence in environmental waters. The biosensor was developed based on tyrosinase immobilization in a polyvinylalcohol photocrosslinkable polymer. It was inserted in a computer-controlled flow system installed besides a photocatalytic reactor including titanium dioxide (TiO2) as photocatalyst. It was shown that the biosensor was able to accurately monitor the paracetamol degradation with time. Compared with conventional HPLC analysis, the described device provides a real-time information on the reaction advancement, allowing a better control of the photodegradation process.

Solar photo-Fenton using peroxymonosulfate for organic micropollutants removal from domestic wastewater: comparison with heterogeneous TiO₂ photocatalysis

This work aims at decontaminating biologically treated domestic wastewater effluents from organic micropollutants by sulfate radical based (SO4(-)) homogeneous photo-Fenton involving peroxymonosulfate as an oxidant, ferrous iron (Fe(II)) as a catalyst and simulated solar irradiation as a light source. This oxidative system was evaluated by using several probe compounds belonging to pesticides (bifenthrin, mesotrione and clothianidin) and pharmaceuticals (diclofenac, sulfamethoxazole and carbamazepine) classes and its kinetic efficiency was compared to that to the well known UV-Vis/TiO2 heterogeneous photocatalysis. Except for carbamazepine, apparent kinetic rate constants were always 10 times higher in PMS/Fe(II)/UV-Vis than in TiO2/UV-Vis system and more than 70% of total organic carbon abatement was reached in less than one hour treatment. Hydroxyl radical (OH) and SO4(-) reactivity was investigated using mesotrione as a probe compound through by-products identification by liquid chromatography-high resolution-mass spectrometry and transformation pathways elucidation. In addition to two OH based transformation pathways, a specific SO4(-) transformation pathway which first involved degradation through one electron transfer oxidation processes followed by decarboxylation were probably responsible for mesotrione degradation kinetic improvement upon UV-Vis/PMS/Fe(II) system in comparison to UVVis/TiO2 system.