Transforming a volcanic rock powder waste into an efficient adsorbent to remove dyes (acid green 16 and acid red 97) and metals (Ag+, Co2+, and Cu2+) from water

This study searched for the best synthesis route for producing an adsorbent from the alkaline fusion of volcanic rock powder waste. The samples synthesized under different conditions of temperature and alkalizing ratio/precursor material, nine in total (NP.F, NP.F1, NP.F2, ...NP.F8 ), were used in the adsorption of acid green 16 (AG 16) and acid red 97 (AR 97) dyes and Ag+, Co2+, and Cu2+ ions. Subsequently, the 22 central composite rotational design (CCRD) was applied, and the effects of the alkalizing ratio (NaOH)/volcanic rock (VR) and temperature (T) on the synthesis process were analyzed in terms of their influence on the physical properties of the materials and in the process of adsorption of contaminants. From the experimental design, it can be seen that the independent variables alkalizing ratio/volcanic rock and temperature greatly influence the characteristic and synthesis of adsorbent materials by alkaline fusion, which in turn reflects on the results achieved in the adsorption of contaminants. Therefore, the temperature of 550 °C and NaOH/VR ratio equal to 1 was the most satisfactory synthesis route to obtain high values of adsorption capacity (q, mg g-1) and removal (R, %) for all studied contaminants, as well as the optimization of the physical characteristics of the material. For example, the adsorption capacity of dye AG 16 was 49.1 mg g-1, and for Ag+ was 66.2 mg g-1, while the removal percentages were 97.6% and 93.4%, respectively. This approach made it possible to transform volcanic rock powder wastes into an efficient adsorbent to treat contaminated waters with dyes and metals.

Ivermectin adsorption by commercial charcoal in batch and fixed-bed operations

Emerging contaminants were used during the COVID-19 pandemic, including ivermectin. Studies that limit the optimal adsorption parameters of ivermectin are scarce in the literature. In this study, we analyzed the adsorption of ivermectin with a high surface area and porosity charcoal. Isotherms were better fitted to the Koble-Corrigan model. The maximum capacity was 203 μg g-1 at 328 K. Thermodynamics indicated a spontaneous and endothermic behavior. The equilibrium was quickly reached within the first few minutes regardless of the ivermectin concentration. The linear driving force (LDF) model fitted the kinetic data (qexp = 164.8 μg g-1; qpred = 148.1 μg g-1) at 100 μg L-1 of ivermectin. The model coefficient (KLDF) and diffusivity (Ds) increased with increasing drug concentration. Two sloped curves were obtained in the column experiments, with a breakthrough time of 415 min and 970 min. The capacity of the column (qeq) was 76 μg g-1. The length of the mass transfer zone was 9.04 and 14.13 cm. Therefore, it can be concluded that the adsorption of ivermectin is highly sensitive to changes in pH, being favored in conditions close to neutrality. Commercial activated charcoal was highly efficient in removing the studied compound showing high affinity with very fast kinetics and a good performance in continuous operation mode.

Adsorptive behavior of multi-walled carbon nanotubes immobilized magnetic nanoparticles for removing selected pesticides from aqueous matrices

The present work synthesized two new materials of functionalized multi-walled carbon nanotubes (MWCNT-OH and MWCNT-COOH) impregnated with magnetite (Fe₃O₄) using solution precipitation methodology. The resulting MWCNT-OH-Mag and MWCNT-COOH-Mag materials were characterized by scanning electron microscopy coupled with energy dispersion X-ray spectroscopy, Fourier transform infrared, X-ray diffraction, atomic force microscopy, and electrical force microscopy. The characterization results indicate that the -OH functional groups in the MWCNT interact effectively with magnetite iron favoring impregnation and indicating the regular distribution of nanoparticles on the surface of the synthesized materials. The adsorption efficiency of the MWCNT-OH-Mag and MWCNT-COOH-Mag materials was tested using the pollutants 2,4-D and Atrazine. Over batch studies carried out under different pH ranges, it was found that the optimal condition for 2,4-D adsorption was at pH 2, while for Atrazine, it was found at pH 6. The rapid adsorption kinetics of 2,4-D and Atrazine reaches equilibrium within 30 min. The pseudo-first-order model described 2,4-D adsorption well. The General-order model described better atrazine adsorption. The magnetically doped adsorbent functionalized with -OH surface groups (MWCNT-OH-Mag) demonstrated superior adsorption performance and increased Fe-doped sites. The Sips model described the adsorption isotherms accurately. MWCNT-OH-Mag presented the greatest adsorption capacity at 51.4 and 47.7 mg g^-1 for 2,4-D and Atrazine, respectively. Besides, electrostatic forces and complexation rule the molecular interactions between metals and pesticides. The leaching and regeneration tests of the synthesized materials indicate high stability in an aqueous solution. Furthermore, experiments with wastewater samples contaminated with the model pollutants indicate that the novel adsorbents are highly promising for enhancing water purification by adsorptive separation.

Wood waste-based functionalized natural hydrochar for the effective removal of Ce(III) ions from aqueous solution

In this study, a sustainable and easily prepared hydrochar from wood waste was studied to adsorb and recover the rare earth element cerium (Ce(III)) from an aqueous solution. The results revealed that the hydrochar contains several surface functional groups (e.g., C-O, C = O, OH, COOH), which largely influenced its adsorption capacity. The effect of pH strongly influenced the Ce(III) removal, achieving its maximum removal efficiency at pH 6.0 and very low adsorption capacity under an acidic solution. The hydrochar proved to be highly efficient in Ce(III) adsorption reaching a maximum adsorption capacity of 327.9 mg g^-1 at 298 K. The kinetic and equilibrium process were better fitted by the general order and Liu isotherm model, respectively. Possible mechanisms of Ce(III) adsorption on the hydrochar structure could be explained by electrostatic interactions and chelation between surface functional groups and the Ce(III). Furthermore, the hydrochar exhibited an excellent regeneration capacity upon using 1 mol L^-1 of sulfuric acid (H₂SO₄) as eluent, and it was reused for three cycles without losing its adsorption performance. This research proposes a sustainable approach for developing an efficient adsorbent with excellent physicochemical and adsorption properties for Ce(III) removal.

Adsorption of the First-Line Covid Treatment Analgesic onto Activated Carbon from Residual Pods of Erythrina Speciosa

In this study, the residual pods of the forest species Erythrina speciosa were carbonized with ZnCl₂ to obtain porous activated carbon and investigated for the adsorptive removal of the drug paracetamol (PCM) from water. The PCM adsorption onto activated carbon is favored at acidic solution pH. The isothermal studies confirmed that increasing the temperature from 298 to 328 K decreased the adsorption capacity from 65 mg g^-1 to 50.4 mg g^-1 (C₀ = 175 mg L^-1). The Freundlich model showed a better fit of the equilibrium isotherms. Thermodynamic studies confirmed the exothermic nature (ΔH⁰ = -39.1066 kJ mol^-1). Kinetic data indicates that the external mass transfer occurs in the first minutes followed by the surface diffusion, considering that the linear driving force model described the experimental data. The application of the material in the treatment of a simulated effluent with natural conditions was promising, presenting a removal of 76.45%. Therefore, it can be concluded that the application of residual pods of the forest species Erythrina speciosa carbonized with ZnCl₂ is highly efficient in the removal of the drug paracetamol and also in mixtures containing other pharmaceutical substances.

The production of activated biochar using Calophyllum inophyllum waste biomass and use as an adsorbent for removal of diuron from the water in batch and fixed bed column

The Calophyllum inophyllum species annually produces a large volume of cylindrical fruits, which accumulate on the soil because they do not have nutritional value. This study sought to enable the use of this biomass by producing activated biochar with zinc chloride as an activating agent for further application as an adsorbent in batch and fixed bed columns. Different methodologies were used to characterize the precursor and the pyrolyzed material. Morphological changes were observed with the emergence of new spaces. The carbonaceous material had a surface area of 468 m² g^-1, D_p = 2.7 nm, and V_T = 3.155 × 10^-1 cm³ g^-1. Scientific and isothermal studies of the adsorption of the diuron were conducted at the natural pH of the solution and adsorbent dosage of 0.75 g L^-1. The kinetic curves showed a good fit to the Avrami fractional order model, with equilibrium reached after 150 min, regardless of the diuron concentration. The Liu heterogeneous surface model well represented the isothermal curves. By raising the temperature, adsorption was encouraged, and at 318 K, the Liu Q_max was reached at 250.1 mg g^-1. Based on the Liu equilibrium constant, the nonlinear van't Hoff equation was employed, and the ΔG° were < 0 from 298 to 328 K; the process was exothermic nature (ΔH⁰ = -46.40 kJ mol^-1). Finally, the carbonaceous adsorbent showed good removal performance (63.45%) compared to a mixture containing different herbicides used to control weeds. The stoichiometric column capacity (q_eq) was 13.30 and 16.61 mg g^-1 for concentrations of 100 and 200 mg L^-1, respectively. The length of the mass transfer zone was 5.326 cm (100 mg L^-1) and 4.946 cm (200 mg L^-1). This makes employing the leftover fruits of the Calophyllum inophyllum species as biomass for creating highly porous adsorbents a very effective and promising option.

Cassava bagasse as an alternative biosorbent to uptake methylene blue environmental pollutant from water

Herein, the methylene blue (MB) biosorption from the agroindustrial residue (cassava bagasse) is reported. The cassava bagasse residue presented an irregular surface, anionic character, and low specific surface area. The experiments were performed in batch mode. The biosorption behavior was investigated through the experimental variables, initial concentration of MB, pH, and temperature. The maximum biosorption capacity (170.13 mg g^-1) reached 328 K and pH 10.0. The equilibrium and kinetics were better fitted by the Sips and general order (R² ≥ 0.997 and R²_adj ≥ 0.996) models, respectively. Furthermore, the thermodynamic study revealed a spontaneous (ΔG⁰ < 0) and endothermic process. Finally, the results showed cassava bagasse is a potential material for biosorption dyes from the aqueous medium. In addition, the biosorbent has a low aggregate cost and high availability, which contributes to the destination of large amounts of waste and inspires engineering applications.

Adsorption of basic fuchsin using soybean straw hydrolyzed by subcritical water

The valorization of agro-industrial residues can be improved through their full use, making the production of second-generation ethanol viable. In this scenario, hydrolyzed soybean straw generated from a subcritical water process was applied to the basic fuchsin adsorption. At pH eight, a high adsorption capacity was obtained. The mass test results showed that basic fuchsin's removal and adsorption capacity could be maximized with an adsorbent dosage of 0.9 g L-1. The linear driving force model was suitable for predicting the kinetic profile, and the kinetic curves showed that equilibrium was reached with only 30 min of contact time. Besides, the Langmuir model was the best to predict the adsorption isotherms. The thermodynamic parameters revealed a spontaneous and endothermic process. At 328 K, there is maximum adsorption capacity (72.9 mg g-1). Therefore, it can be stated that this material could be competitive in terms of adsorption capacity coupled with the idea of full use of waste.

Application of biowaste generated by the production chain of pitaya fruit (Hylocereus undatus) as an efficient adsorbent for removal of naproxen in water

Pharmaceutical compounds are a serious problem in the environment. They cause damage to the aquatic, animal, and human organisms and soon became considered emerging pollutants where their removal is extremely urgent. Among the techniques used, adsorption has been used with success, where several adsorbent materials, including those from residual biomass, have been used to remove these pollutants. In this study, the skins of the pitaya fruit (Hylocereus undatus) productive chain were carbonized with ZnCl₂ to obtain activated carbon and later used in the adsorption of the drug naproxen (NPX) in a batch system. The Freundlich model demonstrated a better adjustment for the equilibrium isotherms. A high adsorption capacity for NPX (158.81 mg g^-1) was obtained at 328 K, which can be attributed to the remarkable textural properties of the adsorbent, besides certain functional groups present on its surface. Thermodynamic studies confirmed the endothermic nature of the adsorption process (∆H⁰ = 0.2898 kJ mol^-1). The linear driving force model (LDF) presented a good statistical adjustment to the experimental kinetic data. The application of the material in the treatment of simulated wastewater composed of various pharmaceutical drugs and salts was very promising, reaching 75.7% removal. Therefore, it can be inferred that the application of activated carbon derived from pitaya bark is highly promising in removing the NPX drug and treating synthetic mixtures containing other pharmaceutical substances.

Volcanic rock powder residues as precursors for the synthesis of adsorbents and potential application in the removal of dyes and metals from water

The present study verified the potential of volcanic rock powder residues originating from the extraction of semi-precious rocks in the state of Rio Grande do Sul, Brazil, as precursors or adsorbents for dyes and metallic ion removal from water. In this way, it is possible to add value and give an adequate destination to this waste. Volcanic rock powder residues from Ametista do Sul (AME) and Nova Prata (NP) were the starting materials. These were used naturally or submitted to the alkaline activation process at 60 °C and alkaline fusion at 550 °C. The analysis of the starting samples by X-ray fluorescence (XRF) revealed that they are mainly composed of aluminum, calcium, iron, and silicon oxides, which corroborates the presence of numerous crystalline phases observed in the X-ray diffraction spectra (XRD). Moreover, by XRD analysis of the synthesized samples, alkaline fusion proved to be more efficient in the dissolution of crystalline phases and consequently in the formation of the amorphous phase (more reactive). Furthermore, the adsorption tests with acid green and acid red dyes and Ag⁺, Co²⁺, and Cu²⁺ ions indicated the viability of using residual volcanic rock powder as raw material for the production of adsorbents functionalized with sodium hydroxide, being that the samples synthesized by alkaline fusion showed better results of removal and adsorption capacity for all the contaminants used in the study.

Development of activated carbon from Schizolobium parahyba (guapuruvu) residues employed for the removal of ketoprofen

Schizolobium parahyba species can be found in all of South America, producing several residues that can be a major opportunity to develop activated carbon. This work presents the investigation regarding the development of a high specific surface activated carbon (981.55 m² g^-1) and its application in the adsorption of ketoprofen from the aqueous media. The ketoprofen molecules were better adhered to the adsorbent surface under acidic conditions (pH = 2), being the ideal adsorbent dosage determined as 0.7 g L^-1, resulting in satisfactory values. It was found that the system reached equilibrium in 200 to 250 min depending on the initial concentration studied, achieving an adsorption capacity of 229 mg g^-1. The general order was the most suitable model for describing the experimental data, with an R² ≥ 0.9985 and MSR ≤ 63.40 (mg g^-1)². The equilibrium adsorption found that the temperature increases the adsorption capacity, achieving 447.35 mg g^-1 at 328 K. Besides that, the Tóth model was the most suitable for describing the isotherms R² ≥ 0.9990 and MSR ≤ 25.67 (mg g^-1)², indicating a heterogeneous adsorbent. The thermodynamic values found that the adsorption of ketoprofen is spontaneous (average ΔG⁰ of - 32.79 kJ mol^-1) and endothermic (ΔH⁰ 10.44 kJ mol^-1). The treatment of simulated effluent with the developed adsorbent was efficient, removing 90% of ketoprofen, ibuprofen, and salts. It was found that the adsorbent is reaming its adsorption capacity up to the 5th cycle, progressively decreasing the adsorption capacity until the adsorption does not occur past the 12th cycle. Overall, the results demonstrated that the activated carbon from residual biomass of the Schizolobium parahyba species could be an excellent alternative in obtaining an effective adsorbent to treat wastewater-containing drugs.

Woody residues of the grape production chain as an alternative precursor of high porous activated carbon with remarkable performance for naproxen uptake from water

Activated carbon prepared from grape branches was used as a remarkable adsorbent to uptake naproxen and treat a synthetic mixture from aqueous solutions. The material presented a highly porous texture, a surface area of 938 m² g^-1, and certain functional groups, which were key factors to uptake naproxen from effluents. The maximum adsorption capacity predicted by the Langmuir model for naproxen was 176 mg g^-1. The thermodynamic study revealed that the adsorption process was endothermic and spontaneous. The linear driving force (LDF) model presented a good statistical adjustment to the experimental decay data. A suitable interaction pathway of naproxen adsorption onto activated carbon was proposed. The adsorbent material was highly efficient to treat a synthetic mixture containing several drugs and salts, reaching 95.63% removal. Last, it was found that the adsorbent can be regenerated up to 7 times using an HCl solution. Overall, the results proved that the activated carbon derived from grape branches could be an effective and sustainable adsorbent to treat wastewaters containing drugs.

Effective adsorptive removal of atrazine herbicide in river waters by a novel hydrochar derived from Prunus serrulata bark

In this work, a novel and effective hydrochar was prepared by hydrothermal treatment of Prunus serrulata bark to remove the pesticide atrazine in river waters. The hydrothermal treatment has generated hydrochar with a rough surface and small cavities, favoring the atrazine adsorption. The adsorption equilibrium time was not influenced by different atrazine concentrations used, being reached after 240 min. The Elovich adsorption kinetic model presented the best adjustment to the kinetic data. The Langmuir model presented the greatest compliance to the isotherm data and indicated a higher affinity between atrazine and hydrochar, reaching a maximum adsorption capacity of 63.35 mg g^-1. Thermodynamic parameters showed that the adsorption process was highly spontaneous, endothermic, and favorable, with a predominance of physical attraction forces. In treating three real river samples containing atrazine, the adsorbent showed high removal efficiency, being above 70 %. The hydrochar from Prunus serrulata bark waste proved highly viable to remove atrazine from river waters due to its high efficiency and low precursor material cost.

Optimization of ketoprofen adsorption from aqueous solutions and simulated effluents using H2SO4 activated Campomanesia guazumifolia bark

This study used the bark of the forest species Campomanesia guazumifolia modified with H₂SO₄ to absorb the anti-inflammatory ketoprofen from aqueous solutions. FTIR spectra confirmed that the main bands remained after the chemical treatment, with the appearance of two new bands related to the elongation of the carbonyl group present in hemicellulose. Micrographs confirmed that the surface started to contain a new textural shape after acid activation, having new pores and cavities. The drug adsorption's optimum conditions were obtained by response surface methodology (RSM). The adsorption was favored at acidic pH (2). The dosage of 1 g L^-1 was considered ideal, obtaining good indications of removal and capacity. The Elovich model very well represented the kinetic curves. The isotherm studies indicated that the increase in temperature negatively affected the adsorption of ketoprofen. A maximum adsorption capacity of 158.3 mg g^-1 was obtained at the lower temperature of 298 K. Langmuir was the best-fit isotherm. Thermodynamic parameters confirmed the exothermic nature of the system (ΔH⁰ = -8.78 kJ mol^-1). In treating a simulated effluent containing different drugs and salts, the removal values were 35, 50, and 80% at 15, 30, and 180 min, respectively. Therefore, the development of adsorbent from the bark of Campomanesia guazumifolia treated with H₂SO₄ represents a remarkable alternative for use in effluent treatment containing ketoprofen.

One step acid modification of the residual bark from Campomanesia guazumifolia using H2SO4 and application in the removal of 2,4-dichlorophenoxyacetic from aqueous solution

The residual bark of the tree species Campomanesia guazumifolia was successfully modified with H₂SO₄ and applied to remove the toxic herbicide 2.4-dichlorophenoxyacetic (2.4-D) from aqueous solutions. The characterization techniques made it possible to observe that the material maintained its amorphous structure; however, a new FTIR band emerged, indicating the interaction of the lignocellulosic matrix with sulfuric acid. Micrographs showed that the material maintained its irregular shape; however, new spaces and cavities appeared after the acidic modification. Regardless of the herbicide concentration, the system tended to equilibrium after 120 min. Using the best statistical coefficients, the Elovich model was the one that best fitted the kinetic data. The temperature increase in the system negatively influenced the adsorption of 2.4-D, reaching a maximum capacity of 312.81 mg g^-1 at 298 K. The equilibrium curves showed a better fit to the Tóth model. Thermodynamic parameters confirmed the exothermic nature of the system (ΔH⁰ = -59.86 kJ mol^-1). As a residue obtained from urban pruning, the bark of Campomanesia guazumifolia treated with sulfuric acid is a promising and highly efficient alternative for removing the widely used and toxic 2.4-D herbicide from aqueous solutions.

Adsorption investigation of 2,4-D herbicide on acid-treated peanut (Arachis hypogaea) skins

In this work, peanut (Arachis hypogaea) skin, a by-product generated by the agricultural production of its seeds, was employed as a precursor in the preparation of an adsorbent for the 2,4-D removal in water. The skins were treated with sulfuric acid and characterized by different techniques. The adsorption was favored at acid pH = 2 with pH_pzc = 6. The dosage of 0.9 g L^-1 was considered ideal, obtaining satisfactory indications of removal and capacity. The kinetic curves were well represented by the general order model, with the equilibrium reached quickly in the first 30 min for all concentrations. Adsorption isotherm studies showed that the increase in temperature negatively affected the herbicide adsorption, obtaining a maximum capacity of 246.72 mg g^-1, by the Langmuir isotherm at 298 K. The remarkable adsorption efficiency presented by the adsorbent can be associated with the presence of new functional groups on the adsorbent surface generated after the acid treatment. Thermodynamic parameters confirmed the exothermic nature of the adsorptive system. In the treatment of synthetic wastewater consisting of a mixture of herbicides and salts, a high removal efficiency (72%) of herbicides was obtained. Therefore, the development of an adsorbent derived from peanut (Arachis hypogaea) skin treated with sulfuric acid is an excellent alternative, generating remarkable removal results towards 2,4-D herbicide.

Adsorption and mass transfer studies of methylene blue onto comminuted seedpods from Luehea divaricata and Inga laurina

In this work, comminuted seedpods of the forest species Luehea divaricata (LDPR) and Inga laurina (ILPR) were used as alternative and environmental-friendly adsorbents for the methylene blue (MB) removal from aqueous solutions. Batch adsorption experiments were carried out at the native pH of the solution (pH = 8.7), with curves of removal and adsorption capacity crossed at 0.75 g L^-1, having 125 mg g^-1 for LDPR and 115 mg g^-1 for ILPR. The kinetic models of pseudo-first-order (PFO) and HSDM-Crank were the most adequate to represent MB dye concentration decay data for both biosorbents. The equilibrium curves were better adjusted by the Langmuir model for both adsorbents, with maximum adsorption capacity increased from 279 to 325 mg g^-1 for LDPR, and 199 to 233 mg g^-1 for ILPR, as a function of an increase in temperature from 298 to 328 K. The thermodynamic parameters showed that both systems are spontaneous with a dominance of physisorption. Mass transfer analysis indicates that the external mass transfer is the limiting step, with Bi < 0.5. Surface diffusion increased with the adsorption capacity, presenting linear and exponential behavior for the ILPR and PLPR adsorbents, respectively. Both materials proved to be efficient in treating a simulated effluent with similar industrial wastewater characteristics, reaching superior values at 70% of color removal.

Successful adsorption of bright blue and methylene blue on modified pods of Caesalpinia echinata in discontinuous system

Pods of the forest species Caesalpinia echinata were used as an alternative adsorbent to remove bright blue (BB) and methylene blue (MB) dyes. The raw and acid-treated samples were characterized by techniques like SEM, XRD, and FTIR. The acid-treated pod sample was characterized by an amorphous structure containing several cavities, bumps, and functional groups. The Elovich model was the most satisfactory to describe the adsorption kinetic data. The isothermal studies were better described by the Langmuir model for BB dye, with a maximum capacity of 261 mg g^-1, and Tóth model for MB dye, giving a maximum capacity of 288 mg g^-1. The thermodynamic study indicated a spontaneous and favorable process and endothermic nature for both dyes. In the treatment of two simulated effluents containing a mixture of different compounds such as dyes and salts, to simulate real wastewaters, the adsorbent was highly efficient, presenting around 80% of color removal for both effluents. Therefore, the acid-treated pods of Caesalpinia echinata have great potential to be applied as an alternative adsorbents in treating colored effluents in discontinuous systems.

Transforming pods of the species Capparis flexuosa into effective biosorbent to remove blue methylene and bright blue in discontinuous and continuous systems

This study investigates, for the first time, the applicability of seed pods from Capparis flexuosa as an alternative biosorbent to remove methylene blue and bright blue from aqueous medium using continuous and batch systems. The biosorbent was characterized by different techniques, whose particles presented rough surface and large pores and functional groups existing on its surface. In the batch system, an adsorptive capacity of 96.40 mg g^-1 and 80% of methylene blue removal was reached with 0.9 g L^-1 of adsorbent at pH 10, whereas 109.7 mg g^-1 and 83% of bright blue removal was observed using 0.8 g L^-1 of adsorbent at pH 2.0. The Elovich model adjusted the experimental data satisfactorily for both dyes. Tóth model for the MB best described the equilibrium data, and the Langmuir model for the bright blue both favored by the increase of temperature and dyes' concentration. The maximum capacities obtained were 280.78 mg g^-1 and 342.85 mg g^-1 for methylene blue and bright blue, respectively. The thermodynamic parameters indicated spontaneous processes, with endothermic behavior for both dyes. The fixed adsorption experiments using Capparis flexuosa seed pods showed adsorptive capacities of 158.65 and 205.81 mg g^-1 for the methylene blue and bright blue, respectively. The overall results indicated that the pods of the Capparis flexuosa could be an ecological, effective, and economical alternative in the removal of dyes for both continuous and batch systems.

[Single balloon versus Inoue balloon in percutaneous mitral balloon valvuloplasty. Short-term results and complications]

PURPOSE

To assess short-term results and complications of percutaneous mitral balloon valvuloplasty (PMBV) performed with Inoue balloon (IB) and single low profile balloon (SB).

METHODS

We performed 390 PMBV procedures, 29 with IB and 337 with SB. There were no differences in age, sex, echocardiographic score distribution and echocardiographic mitral valve area (MVA).

RESULTS

We performed 29 complete procedures with IB and 330 of 337 in SB group. Comparing IB and pre and pos-PMBV data we obtained: mean pulmonary artery pressure (MPAP) 36 +/- 15 and 39 +/- 14 mmHg, p = 0.2033, mean mitral gradient 17 +/- 6 and 20 +/- 77 mmHg, p = 0.0396 and MVA 0.9 +/- 0.2 and 0.9 +/- 0.2 cm2, p = 0.8043 and pos-PMBV:MPAP 25 +/- 8 and 28 +/- 10 mmHg, p = 0.2881, gradient 5 +/- 3 and 5 +/- 4 mmHg, p = 0.2778 and MVA 2.2 +/- 0.2 and 2.0 +/- 0.4 cm2, p = 0.0362. Mitral valve (MV) was competent in 26 patients in IB and in 280 in SB group and we had +/4 mitral regurgitation in 3 patients in IB and in 57 in SB group (p = 0.3591) pre-PMBV respectively and pos-PMBV there was also no difference in MV competence (p = 0.7439).

CONCLUSION

Both techniques were effective. Hemodynamic data were also similar although MVA was greater in IB group after PMBV.

[Percutaneous mitral valvuloplasty with the single balloon technique. Short-term results, complications and in-hospital follow-up]

PURPOSE

To study the short-term results, complication and in-hospital follow-up of 268 percutaneous mitral balloon valvuloplasty (PMBV) procedures performed with the low-profile monofoil balloon (LPMB) technique from 1990 to 1995.

METHODS

A single 30mm balloon diameter was used in 247 (92.9%) procedures, a single 25mm balloon diameter in 9 (3.3%), a single 25mm balloon followed by a single 30mm balloon diameter in 7 (2.6%) and in 5 procedures a balloon was not used. The mean age group was 36 +/- 12 years. Two hundred nineteen (81.7%) procedures were performed in women (mean age 36 +/- 12 years) and 49 (18.3%) in men (mean age, 35 +/- 14 years) (p = 0.78). Patients were in functional class II (NYHA) in 39 (14.5%), class III in 198 (73.9%) and class IV in 31 (11.6%). Patients were in sinus rhythm in 228 (85.1%) procedures and in atrial fibrillation in 40 (14.9%). The echocardiographic score ranged from 4 to 14 (mean 7.2 +/- 1.5).

RESULTS

There were 256 complete procedures, 249 of which were successful (mitral valve area (MVA) > or = 1.5cm2 after PMBV). Echocardiographic calculated MVA before PMBV was 0.9 +/- 0.2cm2. Hemodynamic calculated MVA before PMBV was 0.9 +/- 0.2cm2 and after was 2.0 +/- 0.4cm2 (p < 0.000001). Mean pulmonary artery pressure decreased from 40 +/- 15mmHg to 28 +/- 10mmHg (p < 0.000001) and mitral mean gradient from 20 +/- 7mmHg to 5 +/- 4mmHg (p < 0.000001). In the 256 complete procedures mitral valve (MV) was competent in 214 and there was 1+ mitral regurgitation (MR) in 42. After PMBV, MV was competent in 166 and there was 1+ MR in 68, 2+ in 16, 3+ in 5 and 4+ MR in 1. There were complications in 14 (5.2%) procedures, severe MR in 6 (3 or 4+), stroke in 2 and cardiac tamponade in 6. Two patients died during emergency cardiac surgery after left ventricular perforation and 1 after stroke.

CONCLUSION

PMBV with the LPMB was an effective procedure with a high success rate and a low rate of complications as the more usual double-balloon and Inoue balloon techniques.

[Percutaneous balloon mitral valvoplasty. Immediate results, complications and hospital outcome]

PURPOSE

To study the short-term results, complications and in-hospital follow-up of 223 percutaneous mitral balloon valvuloplasty (PMBV) procedures (proc)in 219 patients.

METHODS

It was used a single 20mm balloon diameter in 4 proc, double balloon in 7, Inoue balloon in 4 and low profile balloon in 196. The mean-age group was 37.19 years. One hundred eighty three (82.1%) procedures were performed in women (mean age, 36.99 years) and 40 (17.9%) in men (mean age, 38.10 years) (p = 0.63). Patients were in functional class II, (NYHA) in 25 (11.2%) procedures, class III in 165 (74.0%) and class IV in 33 (14.8%). Patients were in sinus rhythm in 182 procedures (81.6%) and in atrial fibrillation in 41 (18.4%). The echocardiographic score range from 4 to 14 (7.4% +/- 1.7). Among 4 and 11 were 98.2% of patients.

RESULTS

We had 203 complete proc and success, mitral valve area (MVA) > or = 1.5cm2 after PMBV in 194 proc. Echocardiographic MVA before PMBV was 0.9 +/- 0.2cm2 and after 1.8 +/- 0.3cm2 (p < 0.01). Hemodynamic measures MVA before PMBV was 0.9 +/- 0.2cm2 and after was 1.9 +/- 0.3cm2 (p < 0.01). Mean pulmonary artery pressure decreased from 39 +/- 14mmHg to 27 +/- 11mmHg (p < 0.01) and mitral mean gradient from 20 +/- 9mmHg to 6 +/- 5mmHg (p < 0.01). In the 203 proc, mitral valve (MV) was competent in 176 and there were 1+ mitral regurgitation (MR) in 27. After PMBV, MV was competent in 126, and there were 1+ MR in 60, 2+ in 10.3+ in 6 and 4+ MR in 1. There was complication in 15 proc, severe MR in 7 (3 or 4+), stroke in 3 and cardiac tamponade in 5. Two patients died during emergency cardiac surgery after left ventricular perforation and one by stroke.

CONCLUSION

PMBV was an effective procedure with a high grade of success and low rate of complication.

[Percutaneous transluminal renal angioplasty in the treatment of renovascular hypertension]

PURPOSE

To analyze the effect of percutaneous transluminal renal angioplasty (PTRA) in renovascular hypertension.

METHODS

Twenty-three patients with renal artery stenosis and arterial hypertension underwent PTRA. There were 11 male and 12 female, 19 to 78 years old (45.8 +/- 17.41). In 20 lesions the diagnosis was atherosclerosis, in 7 fibromuscular dysplasia and in 1 Takayasu arteritis. Three patients underwent bilateral dilatation and 2 patients repeated the procedure due to restenosis. Two patients presented with acute renal failure and severe bilateral renal artery stenosis.

RESULTS

There were 21 technical success in 25 procedures. After 20 satisfactory dilatations, clinical success followed in 17 (100% of cases of fibromuscular dysplasia cases and 77% of atherosclerosis. The fall in diastolic arterial pressure after PTRA was statistical significant (p < 0.001). In two cases acute renal failure the renal function became normal after angioplasty. There were 2 complications and no death attributed to PTRA.

CONCLUSION

The method was effective and safe in the management of renovascular hypertension during the short-term follow-up. It was possible in two cases of acute renal failure to normalize renal function.

[Supravalvular aortic stenosis in two black patients]

Two male black patients, 18 and 12-year-old, with mental retardation and typical elfin face, presented with severe supravalvular aortic stenosis, thus characterizing Williams's or aortic supravalvular stenosis syndrome. Both were submitted to surgical treatment of the stenosis, and are asymptomatic after a one and four years follow-up. For the first time this syndrome, in its classical form, is described in black patients.

[Angioplasty of distal aorta and iliac, femoral, popliteal, renal and subclavian arteries. Early and late results]

PURPOSE

To study the late results of peripheral angioplasty.

PATIENTS AND METHODS

In the period of 8 years from August, 1981 until August, 1989, 27 patients were submitted to 33 procedures of peripheral angioplasty.

RESULTS

There was success in 29 procedures, an insufficient dilatation in 1 and and failure in 3 (2 new attempts were effective). Success rate was 88% of the procedures; clinical and angiographic success was reached in 25 (93%) of the 27 patients. Thirty four obstructions were successful dilated: 12 in renal artery, 12 in common iliac artery, 4 in external iliac artery, 3 in superficial femoral artery, 1 in distal aorta. In the evolution we had a restenosis of a renal artery that was redilated, a precocious occlusion of a common iliac artery (9% of common iliac artery dilatations and 6% of the total of the iliac dilatations) and a popliteal occlusion. Of the 34 dilatations we had a patency of 91% until 2 months.

CONCLUSION

Angioplasty showed to be an effective method with good results in the long term follow-up.