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Color removal from wastewater by photocatalytic process using titanium dioxide-coated glass, ceramic tile, and stainless steel sheets
摘要： Dye pollutants from textile industries are a major wastewater problem because they have complex chemical structures. Photocatalysis is a promising wastewater treatment method, which is used to remove dyes under light irradiation in the presence of a photocatalyst. In this article, titanium dioxide (TiO2) photocatalyst was synthesized through sol-gel technique and coated on different substrates (i.e. transparent glass, glazed ceramic tile, and stainless steel) by doctor blade technique. The coated substrates were used in an innovative reactor to remove colors in dye wastewater. The photocatalytic activities of the designed reactor were determined using a synthetic dye wastewater (methylene blue) under UV irradiations (36W-UVA or 30W-UVC lamps). The results showed that the optimum substrate yielded the highest color removal efficiency (93.03 ± 0.66%) was TiO2-coated glass under UVC irradiation. The recycling ability of TiO2-coated glass sheet was also evaluated. It was found that TiO2-coated glass sheet provided the same efficiencies for 20 cycles. In addition, the actual wastewater from textile industry was tested in this study with different pH values (i.e. pH = 3e11). The maximum color removal obtained was 87.86 ± 0.23% at pH value 11 on TiO2-coated glass under UVC irradiation. The color removal was found to decrease with decreasing pH.
关键词： Photocatalysis,Color removal,Wastewater treatment,Titanium dioxide,Dye wastewater
更新于2025-09-23 15:23:52
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Enhanced electrocatalytic production of H2O2 at Co-based air-diffusion cathodes for the photoelectro-Fenton treatment of bronopol
摘要： (Co, S, P)-decorated multiwalled carbon nanotubes (MWCNTs) have been synthesized following a hydrothermal route as electrocatalysts to manufacture large surface area air-diffusion cathodes with carbon cloth as substrate. The enhanced electrocatalytic H2O2 production as compared with Co-free MWCNTs cathodes was demonstrated in a 2.5-L pre-pilot plant with either a RuO2-based or boron-doped diamond (BDD) anode, accumulating between 2- and 3-fold greater H2O2 contents with the catalyzed cathode. The good stability of this new material was ensured from the low Co leaching, with less than 9% Co released to solutions upon repeated usage. Aqueous solutions of the brominated organic preservative bronopol with 0.050 M Na2SO4 at pH 3.0 were comparatively treated by electro-oxidation (EO-H2O2), electro-Fenton (EF), UVA-assisted photoelectro-Fenton (PEF) and solar PEF (SPEF) at constant current density. SPEF with BDD anode and the catalyzed cathode showed the best performance, with total bronopol removal at 210 min and 94% mineralization after 360 min at 40 mA cm-2, thanks to the action of ?OH, BDD(?OH) and sunlight. Formic acid was identified as main reaction by-product, whereas Br and N atoms were mainly converted to Br-, BrO3- and NO3-. Some unidentified organic by-product containing Br and N was formed as well.
关键词： Photoelectro-Fenton process,Bronopol,H2O2 electrogeneration,Wastewater treatment,Pre-pilot plant
更新于2025-09-23 15:23:52
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Artificial neural network modeling of a pilot plant jet-mixing UV/hydrogen peroxide wastewater treatment system
摘要： This study deals with the modeling and simulation of an efficient pilot plant photo-chemical wastewater treatment reactor. Treatment of an azo dye (i.e. direct red 23) was performed using a UV/H2O2 process in a jet mixing photo-reactor with 10-L volume. To model the reactor and simulate the treatment process, six important, influential physical and chemical factors such as nozzle angle (hN), nozzle diameter (dN), flow-rate (Q), irradiation time (t), H2O2 initial concentration ([H2O2]0), and pH, were taken into account. In this regard, artificial neural networks (ANNs) were employed as a powerful modeling methodology. Six different ANN architectures were constructed and most appropriate numbers for hidden neuron and learning iteration were determined based on minimization of the mean square error (MSE) function related to the testing data sets. Furthermore, simulation of the reactor efficiency, as well as sensitivity analysis, was performed via the cross-validation outputs. It was found that a three-layered feed-forward ANN composes ten hidden neurons, calibrated at 100th iteration using “trainlm” as learning algorithm and “tansig” and “purelin” as transfer functions in the hidden and output layers can model the process as the best case. The order of importance for variation of the key factors were indicated as [H2O2]0 > t > pH > Q > hN > dN.
关键词： dyes,simulation,wastewater treatment,Advance oxidation process,neural networks,photodegradation,batch reactor
更新于2025-09-23 15:23:52
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Wastewater treatment using a hybrid system combining adsorption, photocatalytic degradation and membrane filtration processes
摘要： In the present study, Chooka’s Wastewater treatment was investigated using di?erent combinations of adsorption, photocatalytic degradation, and membrane ?ltration process. Polymeric membranes were fabricated using wet phase inversion method employing polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and dimethylformamide (DMF) as a polymer matrix, hydrophilic additive, and solvent, respectively. Activated carbon and TiO2 nanoparticles were selected as an adsorbent and photocatalyst, respectively. TiO2 nanoparticles were synthesized using the sol-gel method and activated carbon was purchased from Merck Company. Liquid-liquid displacement (LLDP), scanning electron microscope (SEM) and contact angle tests were implemented to characterize the fabricated membranes. FT-IR and XRD analysis were also used for TiO2 nanoparticles characterization. The wastewater of Iran pulp and paper factory (Chooka) was used as the feed in separation processes. In hybrid separation systems, 6 di?erent con?gurations were considered and wastewater compositions were measured to determine the e?ectiveness of the utilized processes before and after treatment. Accordingly, the mean pore size of the fabricated PAN/PVP (16%/3%) membrane obtained from LLDP analysis was 9.72 nm. SEM results also indicated thicker active layer for the PAN/PVP membrane than that of the neat PAN membrane. According to the results of the contact angle tests, with the increasing of PVP content in the polymer matrix, the hydrophilicity of membranes improved. It was also found that membrane ?ltration had the best performance among single stage processes and the best separation performance was achieved when photocatalytic degradation, adsorption, and membrane ?ltration were used in series, respectively.
关键词： Photocatalytic degradation,Membrane ?ltration,Adsorption,Hybrid process,Wastewater treatment
更新于2025-09-23 15:22:29
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ZnO Tetrapods for Potential Photocatalytic Dye Degradation
摘要： In this study, a facile method was used to prepare ZnO tetrapods for potential dye degradation applications. Field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX) and UV-Vis spectroscopy were employed to investigate the morphology, chemical composition, and photocatalytic properties of prepared ZnO tetrapods. A Rhodamine B (RB) dye was used as a model dye to study the photocatalytic activity of the prepared sample. It was shown that RB dye can be efficiently degraded in the presence of ZnO tetrapods under continuous UV-light illumination. Thus, prepared ZnO tetrapods with excellent photocatalytic properties can be potentially used in wastewater treatment.
关键词： tetrapods,ZnO,photocatalytic activity,wastewater treatment
更新于2025-09-23 15:22:29
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Influence of Titanium Dioxide Preparation Method on Photocatalytic Degradation of Organic Dyes
摘要： Titanium catalysts (TiO2) were synthesized by three different methods. Their photocatalytic activity was validated through photodegradation of Reactive Red 45 (RR45) azo dye and Acid Blue 25 (AB25) anthraquinone dye in an aqueous solution under UV irradiation. TiO2 photocatalysts were characterized by FTIR, XRD and SEM. Photosensitivity and TiO2 activity range were characterized by UV/Vis spectroscopy. Photocatalytic validation has been made by way of determining the degree of RR45 and AB25 removal. TOC was determined as a measure of the mineralization of RR45 and AB25 by photocatalysis. The stability of TiO2 catalysts and a possibility of using them in consecutive photocatalysis cycles have also been studied. The results show that the photocatalytic efficiency depends on the crystal structure of TiO2. The size of crystallites depends on synthesis conditions. From the results of photocatalytic efficiency it is concluded that the chemical interaction between a catalyst and a dye strongly depends on the dye chemical structure.
关键词： organic dyes,wastewater treatment,photocatalysis,titanium dioxide
更新于2025-09-23 15:22:29
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Green Waste-Derived Substances Immobilized on SBA-15 Silica: Surface Properties, Adsorbing and Photosensitizing Activities towards Organic and Inorganic Substrates
摘要： Urban wastes are a potential source of environment contamination, especially when they are not properly disposed. Nowadays, researchers are finding innovative solutions for recycling and reusing wastes in order to favour a sustainable development from the viewpoint of circular economy. In this context, the lignin-like fraction of biomass derived from Green Compost is a cost-effective source of soluble Bio-Based Substances (BBS-GC), namely complex macromolecules/supramolecular aggregates characterized by adsorbing and photosensitizing properties. In this work BBS-GC were immobilized on a silica support (SBA-15) and the chemico-physical properties of the resulting hybrid material (BBS-SBA) were analysed by zeta-potential measurements, nitrogen adsorption at 77K and micro-calorimetric techniques. Successively, the BBS-SBA photosensitizing and adsorption abilities were tested. Adsorption in the dark of Rhodamine B and Orange II on BBS-SBA and their degradation upon irradiation under simulated solar light were shown, together with the formation of hydroxyl radicals detected by Electron Paramagnetic Resonance spectroscopy. Furthermore, the adsorption of six inorganic ions (Al, Ni, Mn, As, Hg, Cr) on BBS-SBA was studied in pure water at two different pH values and in a landfill leachate, showing the good potential of this kind of materials in the removal of wastewater contaminants.
关键词： photocatalysis,wastewater treatment,orange,adsorption,waste-derived substances,hybrid silica,rhodamine
更新于2025-09-19 17:15:36
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An ultrasound-assisted photocatalytic treatment to remove an herbicidal pollutant from wastewaters
摘要： Pollutants of emerging concern contaminate surface and ground water. Advanced oxidation processes treat these molecules and degrade them into smaller compounds or mineralization products. However, little information on coupled advanced oxidation techniques and on the degradation pathways of these pollutants is available to identify possible ecotoxic subproducts. In the present work, we investigate the ultrasound assisted photocatalytic degradation pathway of the herbicide Isoproturon. We worked in batch mode in a thermostatic glass reactor. We compared the activity of nanometric TiO2 P25 with that of Kronos 1077, a micrometric TiO2. We discuss the individual, additive and synergistic degradation action of photolysis, sonolysis, sonophotolysis, and sonophotocatalysis by varying catalyst loading and/or ultrasound power for the last three techniques. With 0.1 g L?1 catalyst, photocatalysis and sonophotocatalysis completely degrade Isoproturon within 240 min and 60 min, respectively (> 99 % conversion). Sonophotocatalysis breaks Isoproturon down into smaller molecules than photocatalysis alone.
关键词： degradation pathway,wastewater treatment,Isoproturon,sonophotodegradation,micrometric catalyst
更新于2025-09-19 17:15:36
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C,N-doped TiO2 monoliths with hierarchical macro-/mesoporosity for water treatment under visible light
摘要： C,N-doped TiO2 monoliths with homogeneous interconnected macro-/mesoporous hierarchical porosity, consisting in 83% anatase phase, exhibiting high visible light absorption were prepared in one pot synthesis. The hierarchical porosity was controlled by coupling a sol-gel method with a spinodal decomposition and the improved visible light absorption was obtained by self C,N-grafting during thermal treatment. Titanium isopropoxide, N-methylformamide, poly(ethylene oxide), and hydrochloric acid were used as reagents to form a sol, which was then treated at 40 and 60 °C, followed by a solvothermal treatment in autoclave at 200 °C in isopropanol. The monoliths were further heated at different temperatures from 250 to 500 °C under air. The best compromise between the structural and textural properties (TiO2 phase, surface, volume, pore diameter), the visible light absorbance and the mechanical properties was obtained for a calcination at 350 °C for 5 h. In batch mode, in glass containers, the monoliths demonstrated remarkable efficiency as photocatalysts under natural sunlight and artificial visible light with the total discoloration of the azo dye Orange G aqueous solution in 1 h compared to benchmark TiO2 P25 nanoparticles, which proved inefficient under these conditions. More interestingly, the monoliths used as reactors in flow mode in a recirculating system proved very efficient for the total discoloration of Orange G dye solution revealing the high potential of these TiO2 monoliths for continuous flow wastewater treatment under visible light.
关键词： Visible light,TiO2 monolith,Flow process,Dyes degradation,Wastewater treatment,Photocatalysis
更新于2025-09-19 17:15:36
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Photocatalytic decontamination of phenol and petrochemical wastewater through ZnO/TiO <sub/>2</sub> decorated on reduced graphene oxide nanocomposite: influential operating factors, mechanism, and electrical energy consumption
摘要： ZnO/TiO2 anchored on a reduced graphene oxide (rGO) ternary nanocomposite heterojunction was synthesized via the multi-step method including hydrothermal, solvothermal and sol–gel methods. XRD, Raman, FESEM, EDX, Dot Mapping EDS, BET, FTIR, UV-VIS, TGA, and EIS techniques were utilized for characterizing as-synthesized catalysts. The XRD and Raman data proved the formation of anatase phase TiO2 and wurtzite phase ZnO in the prepared samples. Further, the UV-Vis spectrum confirmed that the band gap value of ZnO/TiO2 diminished on introduction of graphene oxide. Photocatalytic performance of the fabricated catalysts was investigated by decontamination of phenol in aqueous solutions. The effect of different operational factors such as pH, catalyst dosage, phenol concentration, and light illumination was investigated to find the optimum decontamination conditions. According to the results, complete degradation of phenol was achieved at pH = 4, catalyst dosage of 0.6 g L?1, light intensity of 150 W, and phenol initial concentration of 60 ppm at 160 min under visible light illumination. With the addition of graphene oxide to the composite, a significant increase was detected in the photocatalytic performance due to the higher available surface area and lower electron/hole recombination rate. In addition, the scavenging experiments revealed that the ?OH is responsible for the degradation of phenol during the reaction. The degradation mechanism, economic performance, mineralization, and recyclability were also investigated. Kinetic studies confirmed that photocatalytic degradation process followed the pseudo-first-order kinetic model. A case of real wastewater treatment was used to examine the performance of the catalyst for real case studies.
关键词： Phenol degradation,Nanocomposite,Wastewater treatment,Photocatalysis,ZnO/TiO2,Reduced graphene oxide
更新于2025-09-19 17:15:36