Оценка эффективности методов очистки сточных вод гальванического производства от аммиачно-тартратных комплексов меди (II)

In recent years, there has been an increasing interest in removal of emerging contaminants in natural waters due to persistence in the aquatic ecosystem. Conventional water treatment processes are generally insufficient for the removal of these contaminants. Depending on this, advanced oxidation processes (AOPs) may be considered as an alternative to this problem. In this study, Fenton process which produces hydroxyl radicals by the reaction between iron salts and hydrogen peroxide was investigated for the removal of some pharmaceutical residues from tap water. The tap water spiked Carbamazepine (CBZ), Caffeine (CAF) and Paracetamol (PRC) with particular concentrations.All initial and final pharmaceutical concentrations were measured separately by LC-MS/MS to calculate percent removal efficiencies accurately. The optimum concentrations are 0.6 mg/L H2O2 − 8 mg/L Fe2+ and 7.5 mg/L H2O2-6 mg/L Fe2+ for CBZ and CAF, respectively. CBZ and CAF removal efficiency have been detected 99.77% and 99.66%. Solutions obtained after CAF removal were re-measured in LC-MS/MS for 1,7 dimethylxanthine. But 1,7 dimethylxanthine (paraxanthine) which was studied as a by-product of CAF could not be determined on measurements. 99.11% removal efficiency was obtained for PAR at 5 mg/L H2O2 and 10 mg/L Fe2+ concentration. Increased H2O2 and Fe2+ concentration affect the yield of Fenton oxidation in all pharmaceutical residues.

Advanced oxidative processes (AOPs) have been extensively investigated for the removal of a wide range of organic contaminants, including dyes, pharmaceuticals, and other industrial pollutants. However, systematic evaluations of synergistic effects among different AOP configurations remain limited. This study investigated the synergistic interactions between AOPs for the degradation and mineralization of Rhodamine B, a dye widely used as a model compound for industrial effluents. Solutions were treated using photolysis (UV), hydrogen peroxide (H2O2), UV/H2O2, Fenton (Fe2+/H2O2), and photo-Fenton (Fe2+/H2O2/UV) processes. H2O2 concentrations ranged from 1.6 to 43.2 mmol/L when applied alone and from 0.53 to 4.8 mmol/L in Fenton and photo-Fenton systems, using Fe2+/H2O2 ratios of 1:5 and 1:10. The results revealed that the UV/H2O2 achieved 69% degradation within 2 h at 14.4 mmol/L of H2O2, outperforming the individual treatments. The photo-Fenton process exhibited superior efficiency, achieving complete degradation in half the time required by the Fenton process at 0.5 mmol/L of H2O2 and an Fe2+/H2O2 ratio of 1:5. Furthermore, mineralization increased by 20% when UV was incorporated. This study demonstrates that integrating AOPs enhances the performance, supporting the optimization of the treatments for dye-containing wastewaters and reinforcing the importance of synergistic strategies for environmental remediation.

A critical review of advanced oxidation processes for emerging trace organic contaminant degradation: Mechanisms, factors, degradation products, and effluent toxicity

Magnetically recoverable Fe3O4@polydopamine nanocomposite as an excellent co-catalyst for Fe3+ reduction in advanced oxidation processes

With the increasing severity of global water pollution, traditional wastewater treatment methods have gradually revealed limitations in dealing with complex and refractory pollutants. Advanced oxidation processes (AOPs) have emerged as a promising alternative due to their ability to generate highly reactive radicals (such as hydroxyl and sulfate radicals) that can effectively degrade a wide range of pollutants. This review provides a detailed overview of various AOP technologies, including Fenton processes, ozone-based AOPs, persulfate-based AOPs, photocatalytic AOPs, electrochemical AOPs, and sonochemical AOPs, focusing on their fundamental principles, reaction mechanisms, catalyst design, and application performance in treating different types of wastewater. The research results show that the improved Fenton process can achieve a chemical oxygen demand (COD) removal rate of up to 85% when treating pharmaceutical wastewater. Photocatalytic AOP technology demonstrates higher degradation efficiency when treating industrial wastewater containing refractory pollutants. In addition to effectively degrading refractory pollutants and reducing dependence on traditional biological treatment methods, these advanced oxidation processes can also significantly reduce secondary pollution generated during the treatment process. Moreover, by optimizing AOP technologies, the deep mineralization of harmful substances in wastewater can be achieved, reducing the potential pollution risks to groundwater and soil while also lowering energy consumption during the treatment process. Additionally, this review discusses the challenges faced by AOPs in practical applications, such as high energy consumption, insufficient catalyst stability, and secondary pollution. This review summarizes the research progress and application trends of catalytically driven AOPs in the field of wastewater treatment over the past five years. It aims to provide a comprehensive reference for researchers and engineering professionals on the application of AOPs in wastewater treatment, promoting the further development and practical implementation of these technologies.

Hydrogen peroxide (HP) is widely used in advanced oxidation processes (AOPs). This study evaluates the chemical oxygen demand (COD) removal efficiency of Acid Orange 8 (AO 8) at a higher concentration by modified Fenton processes using substituted HP such as tert-butyl hydroperoxide (TBHP) and sodium perborate (SPB) and sodium persulphate (SPS) as oxidants. Under optimal conditions, COD removal was found to be 72.8 and 58.9% at pH 3.0 and 6.5 in the Fenton process in 300 min.The COD removal efficiency of different systems is in the order: Fe2+/SPB>Fe2+/HP>Fe2+/TBHP>Fe2+/SPS indicating the possibility of using SPB as a substitute for HP and SPS. The order of efficiency is attributed, among other factors, to their ability to produce HO. radicals. Various anions are shown to exhibit an inhibitory effect in the order: I->Br->F->Cl->SO42->NO3-. The inhibitory effect of Cl- is observed at higher concentrations than F- and Br-, even though I- displays inhibition at all concentrations. Finally, COD removal kinetics and the degradation mechanism, based on the identified intermediate products, were determined in this study.

This study aimed to disclose migration and transformation of heavy metal and arsenic compounds in the soil-microorganisms-plant system. Plants have been grown on soil inoculated with experimental rhizobacteria Azotobacter and Bacillus. In our experiment, soil samples were collected close to the industrial site of the former Angarsk Metallurgical Plant (AMP) used to produce arsenic (Svirsk town, Eastern Siberia) and from background site. High As, Pb and Cd abundances, dozens and hundreds of times exceeding the Maximum Permissible Concentrations (MPC), were found in the soil around the former plant. Each soil sample was divided into control soil and soil inoculated with rhizobacteria used for plant growing. Concentrations of chemical elements were analyzed in easily exchangeable, carbonate, organic, and Fe hydroxide-associated fractions and chelate forms. Rhizobacteria initiate arsenic and heavy metals immobilization in organic fraction. The highest element abundances were found in the chelate form in soil inoculated by rhizobacteria. The intensity of As and heavy metals accumulation in the plants grown on the inoculated soil is markedly low, owing to biological adsorption of elements by the cells of rhizobacteria capable of creating a barrier for their supply into plants. The study of As and heavy metals behavior under the influence of rhizobacteria is of great importance in developing new biotechnologies related to soil remediation and crop production.

Advanced oxidation processes which produce hydroxyl radicals with high oxidation potential have come forward among the methods used in the treatment of industrial wastewaters containing organic pollutants that are difficult to biodegrade. The application of UV rays with the fentanyl reactivity showed that the organic material is more fragmented and the degradation rate is higher. In this study, Fenton process and photo-Fenton process were applied to industrial wastewater of paper. In experimental studies, optimum experimental parameters such as iron ion and hydrogen peroxide concentrations, pH, temperature, reaction time, mixing speed and light intensity were determined and processes were compared. 70% color and 51% chemical oxygen demand (COD) removal in the Fenton process; 96% color and 90% COD removal in the photo-Fenton process were obtained. The addition of UV radiation to the oxidation process resulted in better degradation of organic contaminants and enhanced color and COD removal efficiency. Although the optimum reaction time of the Fenton process was 120 minutes, the optimum reaction time of the photo-Fenton process was 60 minutes.

The improvement of various advancements for water sanitization is a significant issue. Among numerous elective drinking water treatment advances, the well-known disinfectant techniques are ozonation and chlorination to treat drinking water. All through the ozonation procedure, it produces biodegradable organic by-products while in the chlorination process, some risky by-products (trihalomethanes and haloacetic acids) are generated. Because of the possible danger of these results, several water purification methods have been reported, such as ozonation, chlorination, UV, etc. During ozonation, exceptionally reactive hydroxyl radicals are produced, which has a crucial effect on purifying water. In this paper, we have discussed the wide use of ozone disinfectants for water treatment with an emphasis on radical chemistry of ozonization as well as advanced oxidation processes instead of the chlorination process, low-cost ozone generation processes, the impact of ozone and chlorine disinfectants on cryptosporidium oocysts, and the removal of seven strains microbes from drinking water. The favorable circumstances, hindrances of the utilization of ozone and chlorine in wastewater treatment, and their confinements in water treatment innovation just as the elective advances, for example, ozone-based oxidation process, catalytic ozonation, photocatalytic oxidation, and so on are additionally clarified in this paper.

Dynamics of Topology-dependent Water Purification by Siliceous Zeolite Membranes

Wastewater generated from industrial processes including the batik industry in Indonesia contains high organic pollutants and dyes. In this study, the advanced oxidation process that will produce hydroxyl radicals was used to degrade pollutants in this batik industry wastewater. This study aims to compare the Fenton and Persulfate processes with the influence of variations in the concentration of Fe2+ and S2O8 2- added. This method is carried out by adding H2O2 as an oxidant which is added to each catalyst, namely Fe2+ and S2O8 2- in the presence of a combination of UV light. Fenton process was carried out in 60 minutes and Persulfate process was carried out in 45 minutes. In this study, there was a tendency to increase the efficiency of COD and color removal along with the increasing concentration of each catalyst added. The highest COD and color removal efficiency occurred at a ratio of H2O2:Fe2+ and H2O2: S2O8 2- of 1: 0.08.

Chapter 8 - Advance oxidation processes for wastewater treatment: A crucial tool for sustainability

Wastewater from the textile industry containing a high concentration of organic and inorganic chemicals has strong color and residual chemical oxygen demand (COD). Therefore, advanced oxidation processes (AOPs) are very good candidates to treat textile industry wastewater. In this study, we investigated the effect of different types of AOPs supported with hydrogen peroxide (H2O2) for the treatment of viscose fibers dyeing wastewater. Fenton, photo-Fenton, and Fenton-supported subcritical water oxidation (FSWO) processes were chosen as AOPs to compare the treatment efficiency of viscose fibers dyeing wastewater. The effects of solution pH, Fe2+ concentration, and H2O2 concentration on the treatment of viscose fibers dyeing wastewater were tested. The maximum color and COD removal efficiency was obtained corresponding to pH 2.5 for all oxidation methods when methylene blue (MB) dye solution was used. However, the maximum efficiencies were obtained at pH 3.0 for real textile wastewater decolorization. The MB dye removal efficiency was increased to 97.22, 100, and 100% for Fenton, photo-Fenton, and FSWO processes, respectively, when the addition of H2O2 concentration was adjusted to 125 mg/L. However, the maximum color removal efficiencies of viscose fibers dyeing wastewater were obtained 56.94, 61.26, 64.11% for Fenton, photo-Fenton, FSWO processes, respectively. As a result, the FSWO showed maximum color removal efficiencies.

Landfill leachate treatment using combined fish scales based activated carbon and solar advanced oxidation processes

Optimization of conventional Fenton and ultraviolet-assisted oxidation processes for the treatment of reverse osmosis retentate from a paper mill