Hybrid UV/COP advanced oxidation process using ZnO as a catalyst immobilized on a stone surface for degradation of acid red 18 dye

Azo dyes are the largest group of synthetic organic dyes which containing the linkage CsbndNdbndNsbndC and used in various industries such as textile industries leather articles, and some foods. Azo dyes are resistant compounds against the biodegradation processes. The purpose of this research was hybrid UV/COP advanced oxidation process using ZnO as a catalyst immobilized on a stone surface for degradation of acid red 18 (AR18) Dye. In the hybrid process using some parameters such as the dye initial concentration, pH, contact time and catalyst concentration, the process efficiency was investigated. In order to the dye removal, the sole ozonation process (SOP), catalytic ozonation process (COP) and photocatalytic process (UV/ZnO) were used. The ZnO nanoparticles were characterized by XRD, SEM and TEM analyses. The maximum dye removal was achieved 97% at the dye initial concentration 25 mg/L, catalyst concentration 3 g/L, contact time 40 min and pH 5. As a real sample, the Yazdbaf textile factory wastewater was selected. After that, the physicochemical quality was evaluated. As well as, in the optimal conditions, the AR18 dye removal efficiency was achieved 65%. The kinetic results demonstrated that the degradation reaction was fitted by pseudo-first-order kinetic. The UV/COP hybrid process had high efficiency for removal of resistant dyes from the textile wastewater. Advantages of this technique were as follows: � ZnO nanoparticles were synthesized as catalyst by thermal method and were immobilized on the stones. � pH changes had no significant effect on the removal efficiency. � In the kinetic studies, the decomposition reaction followed pseudo-first order kinetic. © 2020 The Author

Microwave-assisted preparation of ZnFe2O4@methyl cellulose as a new nano-biomagnetic photocatalyst for photodegradation of metronidazole

In the present study, ZnFe2O4@methyl cellulose (MC) nano-biomagnetic photocatalyst was rapidly prepared based on a microwave-assisted method. FTIR, FESEM, EDS, UV-DRS, XRD, and VSM were performed to characterize the structure of as-prepared ZnFe2O4@MC. The removal efficiency of Metronidazole (MNZ) degradation was 92.65 and 71.12 in synthetic and real samples under optimal conditions, respectively. The removal efficiency of TOC was also reported to be 77.87 under optimal conditions. The kinetic linear models showed that the photocatalytic degradation of MNZ follows either a pseudo-first-order kinetic or the Langmuir-Hinshelwood model. The correlation coefficients (R2) were 0.92, 0.97, 0.99, and 0.94, respectively at 5, 10, 20, and 30 mg/L. The equilibrium adsorption coefficient (KL � H) of the Langmuir-Hinshelwood model and the superficial reaction rate constant (Kc) were 0.633 Lmg�1 and 0.203 mg/L min�1, respectively. The participation of active species such as holes and hydroxyl and superoxide radicals was studied during MNZ photodegradation with organic and inorganic radical scavengers. Finally, the nano-biomagnetic catalyst could be reused for six further runs without remarkable changes in catalytic efficiencies. In this study, we present a new magnetic nanocomposite and a novel strategy for antibiotic removal from aqueous media. © 2020 Elsevier B.V

Removal of metronidazole from wastewater by Fe/charcoal micro electrolysis fluidized bed reactor

The aim of the research was to investigate the removal of metronidazole from aqueous solutions by Fe/charcoal micro-electrolysis fluidized bed reactor. The effective variables influencing the metronidazole removal including the initial pH of the solution, the initial concentration of metronidazole, contact time, aeration rate and Fe/charcoal ratio were studied. The amount of secondary iron ions pollution in the reactor effluent was investigated by a flame atomic absorption device. Degradation reaction kinetics were studied. The removal efficiency of metronidazole in the actual hospital wastewater sample was investigated under optimal conditions of the reactor. The stability and performance of the reactor was investigated through 4 consecutive cycles. Data analysis was performed by SPSS-16. The maximum removal efficiencies were obtained in optimal conditions including pH: 7, the contact time of 70 min, aeration rate of 6 L/min, charcoal/Fe ratio 1:1 and initial concentration of metronidazole of 10 mg/L as 90 and 78 percent for synthetic solutions and actual wastewater respectively. No secondary pollution of iron ions was detected. In the study of linear kinetic models, the degradation process followed pseudo-first kinetic order. The Fe/charcoal micro-electrolysis system is well-suited for efficient removal of antibiotics from aqueous solutions and applies to industrial scale. - 2019 Elsevier Ltd.This paper was carried out under the supervision of the Environmental Health Engineering Research Center. Kerman University of Medical Sciences with the support of the Vice-Chancellor for Research and Technology, Department of the University. We thank them for their help.Scopu

Decoloration of textile Acid Red 18 dye by hybrid UV/COP advanced oxidation process using ZnO as a catalyst immobilized on a stone surface

Azo dyes are one of the most important groups of synthetic dyes. These dyes are compounds resistant against decomposition by biological processes and are used in textile industries. The aim of this study was to decoloration of textile Acid Red 18 dye by hybrid UV/catalytic ozonation process (COP) advanced oxidation process (AOP) using ZnO (synthesized by thermal method) as a catalyst, immobilized on a stone surface. The process efficiency was investigated using parameters of pH, contact time, catalyst concentration and initial concentration of dye in the hybrid process. Dye removal mechanisms were identified in the sole ozonation process, COP and photocatalytic process (UV/ ZnO). X-ray diffraction, scanning electron microscopy and transmission electron microscopy analyses were used to study the structural properties, morphology, and size of the ZnO nanoparticles. 97 dye removal was obtained at a contact time of 40 min, pH: 5, catalyst concentration of 3 g/L and dye initial concentration of 25 mg/L. The Yazdbaf textile factory wastewater was selected as a real sample and its physicochemical quality was determined. Also, the Acid Red 18 dye removal efficiency was obtained 65 in the optimal conditions. Kinetic studies showed that the decomposition reaction follows pseudo-first-order kinetics. The UV/COP hybrid process as an AOP has high efficiency in removing resistant dye contaminants from textile wastewater. © 2020 Desalination Publications

Removal of metronidazole from wastewater by Fe/charcoal micro electrolysis fluidized bed reactor

The aim of the research was to investigate the removal of metronidazole from aqueous solutions by Fe/charcoal micro-electrolysis fluidized bed reactor. The effective variables influencing the metronidazole removal including the initial pH of the solution, the initial concentration of metronidazole, contact time, aeration rate and Fe/charcoal ratio were studied. The amount of secondary iron ions pollution in the reactor effluent was investigated by a flame atomic absorption device. Degradation reaction kinetics were studied. The removal efficiency of metronidazole in the actual hospital wastewater sample was investigated under optimal conditions of the reactor. The stability and performance of the reactor was investigated through 4 consecutive cycles. Data analysis was performed by SPSS-16. The maximum removal efficiencies were obtained in optimal conditions including pH: 7, the contact time of 70 min, aeration rate of 6 L/min, charcoal/Fe ratio 1:1 and initial concentration of metronidazole of 10 mg/L as 90 and 78 percent for synthetic solutions and actual wastewater respectively. No secondary pollution of iron ions was detected. In the study of linear kinetic models, the degradation process followed pseudo-first kinetic order. The Fe/charcoal micro-electrolysis system is well-suited for efficient removal of antibiotics from aqueous solutions and applies to industrial scale. © 2019 Elsevier Ltd