scholarly journals Photochemical degradation of benzene, toluene, ethylbenzene, and xylenes (BTEX) using UV/H₂0₂

2021 ◽  
Author(s):  
Durkhani Kakar
Keyword(s):  
Residence Time ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Acidic Condition ◽  
Photochemical Degradation ◽  
Oxidation Processes ◽  
Toc Removal ◽  
In Series ◽  
Benzene Toluene ◽  
Oxidation Of Benzene

The oxidation of benzene, toluene, ethylbenzene, and xylenes (BTEX) by advanced oxidation processes in water was investigated. The degradation of BTEX by UV-185 and UV-254 nm in conjunction with H₂O₂ was studied. It was observed that the recommended H₂0₂ concentration to degrade 100 mgTOC/L of BTEX was 250 mg/L and 300 mg/L for UV-185 and UV-254 nm, respectively. In addition, it was observed that using the lamps in series did not have any advantages in the TOC removal of BTEX. Under acidic condition, pH 3, UV-185/H₂O₂ removed 10% more than UV-254/H₂O₂. At the recommended H₂O₂ concentration, 90% of BTEX mineralization was occurred with UV-185 nm/HO₂ under acidic condition of pH 3. It was observed that 21-32% BOD/TOC ratio of BTEX was decreased with an increase in residence time (within 140 min) in the photoreactor.

scholarly journals Photochemical degradation of benzene, toluene, ethylbenzene, and xylenes (BTEX) using UV/H₂0₂

2021 ◽  
Author(s):  
Durkhani Kakar
Keyword(s):  
Residence Time ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Acidic Condition ◽  
Photochemical Degradation ◽  
Oxidation Processes ◽  
Toc Removal ◽  
In Series ◽  
Benzene Toluene ◽  
Oxidation Of Benzene

The oxidation of benzene, toluene, ethylbenzene, and xylenes (BTEX) by advanced oxidation processes in water was investigated. The degradation of BTEX by UV-185 and UV-254 nm in conjunction with H₂O₂ was studied. It was observed that the recommended H₂0₂ concentration to degrade 100 mgTOC/L of BTEX was 250 mg/L and 300 mg/L for UV-185 and UV-254 nm, respectively. In addition, it was observed that using the lamps in series did not have any advantages in the TOC removal of BTEX. Under acidic condition, pH 3, UV-185/H₂O₂ removed 10% more than UV-254/H₂O₂. At the recommended H₂O₂ concentration, 90% of BTEX mineralization was occurred with UV-185 nm/HO₂ under acidic condition of pH 3. It was observed that 21-32% BOD/TOC ratio of BTEX was decreased with an increase in residence time (within 140 min) in the photoreactor.

scholarly journals Persulfate Process Activated by Homogeneous and Heterogeneous Catalysts for Synthetic Olive Mill Wastewater Treatment

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3010
Author(s):  
Eva Domingues ◽  
Maria João Silva ◽  
Telma Vaz ◽  
João Gomes ◽  
Rui C. Martins
Keyword(s):  
Phenolic Compounds ◽  
Red Mud ◽  
Advanced Oxidation Processes ◽  
Heterogeneous Catalysts ◽  
Advanced Oxidation ◽  
Iron Sulfate ◽  
Toxicity Tests ◽  
Oxidation Processes ◽  
Toc Removal ◽  
Olive Mill

Wastewaters from the olive oil industry are a regional environmental problem. Their phenolic content provides inherent toxicity, which reduces the treatment potential of conventional biological systems. In this study, Sulfate Radical based Advanced Oxidation Processes (SRbAOPs) are compared with advanced oxidation processes (namely Fenton’s peroxidation) as a depuration alternative. Synthetic olive mill wastewaters were submitted to homogeneous and heterogeneous SRbAOPs using iron sulfate and solid catalysts (red mud and Fe-Ce-O) as the source of iron (II). The homogenous process was optimized by testing different pH values, as well as iron and persulfate loads. At the best conditions (pH 5, 300 mg/L of iron and 600 mg/L of persulfate), it was possible to achieve 39%, 63% and 37% COD, phenolic compounds and TOC removal, respectively. The catalytic potential of a waste (red mud) and a laboratory material (Fe-Ce-O) was tested using heterogenous SRbAOPs. The best performance was achieved by Fe-Ce-O, with an optimal load of 1600 mg/L. At these conditions, 27%, 55% and 5% COD, phenolic compounds and TOC removal were obtained, respectively. Toxicity tests on A. fischeri and L. sativum showed no improvements in toxicity from the treated solutions when compared with the original one. Thus, SRbAOPs use a suitable technology for synthetic OMW.

scholarly journals Organic Degradation Potential of Real Greywater Using TiO2-Based Advanced Oxidation Processes

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2811
Author(s):  
Dheaya Alrousan ◽  
Arsalan Afkhami ◽  
Khalid Bani-Melhem ◽  
Patrick Dunlop
Keyword(s):  
Advanced Oxidation Processes ◽  
Low Cost ◽  
Advanced Oxidation ◽  
Molar Ratio ◽  
Organic Fraction ◽  
Viable Option ◽  
Oxidation Processes ◽  
Toc Removal ◽  
Uva Irradiation ◽  
Efficiency Parameter

In keeping with the circular economy approach, reclaiming greywater (GW) is considered a sustainable approach to local reuse of wastewater and a viable option to reduce household demand for freshwater. This study investigated the mineralization of total organic carbon (TOC) in GW using TiO2-based advanced oxidation processes (AOPs) in a custom-built stirred tank reactor. The combinations of H2O2, O3, and immobilized TiO2 under either dark or UVA irradiation conditions were systematically evaluated—namely TiO2/dark, O3/dark (ozonation), H2O2/dark (peroxidation), TiO2/UVA (photocatalysis), O3/UVA (Ozone photolysis), H2O2/UVA (photo-peroxidation), O3/TiO2/dark (catalytic ozonation), O3/TiO2/UVA (photocatalytic ozonation), H2O2/TiO2/dark, H2O2/TiO2/UVA, H2O2/O3/dark (peroxonation), H2O2/O3/UVA (photo-peroxonation), H2O2/O3/TiO2/dark (catalytic peroxonation), and H2O2/O3/TiO2/UVA (photocatalytic peroxonation). It was found that combining different treatment methods with UVA irradiation dramatically enhanced the organic mineralization efficiency. The optimum TiO2 loading in this study was observed to be 0.96 mg/cm2 with the highest TOC removal (54%) achieved using photocatalytic peroxonation under optimal conditions (0.96 mg TiO2/cm2, 25 mg O3/min, and 0.7 H2O2/O3 molar ratio). In peroxonation and photo-peroxonation, the optimal H2O2/O3 molar ratio was identified to be a critical efficiency parameter maximizing the production of reactive radical species. Increasing ozone flow rate or H2O2 dosage was observed to cause an efficiency inhibition effect. This lab-based study demonstrates the potential for combined TiO2-AOP treatments to significantly reduce the organic fraction of real GW, offering potential for the development of low-cost systems permitting safe GW reuse.

Comparative Study of Advance Oxidation Processes for Treatment of Pesticide Wastewater

2019 ◽  
pp. 261-323
Author(s):  
Augustine Chioma Affam ◽  
Malay Chaudhuri
Keyword(s):  
Energy Efficiency ◽  
Comparative Study ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Cost Effective ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Oxidation Processes ◽  
Toc Removal ◽  
The Cost

This study compared the amount of catalyst and energy efficiency required for operation of five advanced oxidation processes (Fenton, UV photo-Fenton, solar photo-Fenton, UV/TiO2/H2O2, and FeGAC/H2O2) for degradation of the pesticides chlorpyrifos cypermethrin and chlorothalonil wastewater. Under optimum operating conditions, degradation in terms of COD and TOC removal and biodegradability (BOD5/COD ratio) index (BI) were observed to be (1) Fenton – 69.03% (COD), 55.61% (TOC), and 0.35 (BI); (2) UV photo-Fenton – 78.56% (COD), 63.76% (TOC), and 0.38 (BI); (3) solar photo-Fenton – 74.19% (COD), 58.32% (TOC), and 0.36 (BI); (4) UV/TiO2/H2O2 – 53.62% (COD), 21.54% (TOC), and 0.26 (BI); and (5) FeGAC/H2O2 – 96.19% (COD), 85.60% (TOC), and 0.40 (BI). The cost was $39.9/kg TOC (Fenton), $34.1/kg TOC (UV photo-Fenton), $30.1/kg TOC (solar photo-Fenton), $239/kg TOC (UV/TiO2/H2O2), and $0.74/kg TOC (FeGAC/H2O2). The FeGAC/H2O2 process was found to be most efficient and cost effective for pretreatment of the pesticide wastewater for biological treatment.

scholarly journals Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution

2018 ◽  
Vol 13 (1) ◽  
pp. 179 ◽  
Author(s):  
Augustine Chioma Affam ◽  
Malay Chaudhuri ◽  
Shamsul Rahman M. Kutty
Keyword(s):  
Aqueous Solution ◽  
Biological Treatment ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Economic Cost ◽  
Cost Effective ◽  
Reaction Engineering ◽  
Oxidation Processes ◽  
Toc Removal ◽  
Degradation Rate Constant

The study compared the technical efficiency and economic cost of five advanced oxidation processes (Fenton, UV photo-Fenton, solar photo-Fenton, UV/TiO2/H2O2 and FeGAC/H2O2) for degradation of the pesticides chlorpyrifos cypermethrin and chlorothalonil in aqueous solution. The highest degradation in terms of COD and TOC removals and improvement of the biodegradability (BOD5/COD ratio) index (BI) were observed to be (i) Fenton - 69.03% (COD), 55.61% (TOC), and 0.35 (BI); (ii) UV photo-Fenton -78.56% (COD), 63.76% (TOC) and 0.38 (BI);  (iii) solar photo-Fenton - 74.19% (COD), 58.32% (TOC) and 0.36 (BI); (iv) UV/TiO2/H2O2 - 53.62% (COD), 21.54% (TOC), and 0.26 (BI); and  (v) the most technical efficient and cost effective process was FeGAC/H2O2. At an optimum condition (FeGAC 5 g/L, H2O2 100 mg/L, and reaction time of 60 min at pH 3), the COD and TOC removal efficiency were 96.19 and 85.60%, respectively, and the biodegradation index was 0.40. The degradation rate constant and cost were 0.0246 min-1 and $0.74/kg TOC, respectively. The FeGAC/H2O2 process is the most technically efficient and cost effective for pretreatment of the pesticide wastewater before biological treatment. Copyright © 2018 BCREC Group. All rights reservedReceived: 26th July 2017; Revised: 26nd September 2017; Accepted: 27th September 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Affam, A.C., Chaudhuri, M., Kutty, S.R.M. (2018). Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 179-186 (doi:10.9767/bcrec.13.1.1394.179-186) 

scholarly journals Treatability Studies of Hospital Wastewaters with AOPs by Taguchi’s Experimental Design

2017 ◽  
Vol 19 (3) ◽  
pp. 505-510 ◽  
Keyword(s):  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Taguchi’S Method ◽  
Orthogonal Array Design ◽  
Oxidation Treatment ◽  
Oxidation Processes ◽  
Toc Removal ◽  
Operation Conditions ◽  
Treatment Processes ◽  
Hospital Wastewaters

In this study, it was studied various advanced oxidation treatment processes; Fenton, UV/H2O2, UV/O3/H2O2 for treatability of hospital wastewaters containing antibiotics (cephalosporines). Taguchi’s L25 orthogonal array design was applied to design of advanced oxidation processes, for simplification of the analysis and calculations. 95,7%, 90,65%, 91,8% COD and 55,86%, 60,83%, 70,8% TOC removal efficiencies were obtained under the best operation conditions for UV/H2O2, UV/O3/H2O2 and Fenton processes, respectively. According to the ANOVA results, pH was of great importance in COD removal for Fenton. For the UV/H2O2 processes, H2O2 has significance in COD and TOC removals. As for the O3/UV/H2O2 processes, O3/UV reaction time was found as an important parameter effecting the removal rates. Also, cephalosporine antibiotic active compounds (cefradine and cefaclor) were degraded completely within minutes for all of the processes. Taguchi’s Method was found useful for the environmental applications and simplifications of advanced oxidation processes for treatment of hospital wastewaters and calculations.

Solar-driven advanced oxidation processes for full mineralisation of azo dyes in wastewater

2017 ◽  
Vol 14 (3) ◽  
pp. 188 ◽  
Author(s):  
Chunhong Nie ◽  
Pingping Sun ◽  
Lingyue Zhu ◽  
Simeng Gao ◽  
Hongjun Wu ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Solar Energy ◽  
Small Molecules ◽  
Azo Dyes ◽  
Industrial Wastewater ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Azo Compounds ◽  
Oxidation Processes ◽  
Toc Removal

Environmental contextFull mineralisation of synthetic azo dyes in industrial wastewater is a tough job for traditional wastewater treatment technologies. There is an urgent need for the development of both sustainable and environmentally friendly technology capable of fully mineralising these azo compounds. We show that solar-driven advanced oxidation processes are capable of completely mineralising azo compounds with high utilisation of solar energy. AbstractMineralisation of synthetic azo dyes in industrial wastewater is an energy-intensive process in treatment technology. The Solar Thermal Electrochemical Process for advanced oxidation processes (STEP-AOPs) utilises solar energy and electricity for the activation and electrooxidation of organic pollutants to harmless, small and non-toxic molecules with no other energy consumption. Based on molecular structure and chemistry, the STEP-AOPs for the treatment of azo dyes in wastewater, as exemplified with a typical azo dye, methyl orange, is reported for the first time. Thermodynamic calculations of the temperature-dependent potentials of methyl orange demonstrate that Gibbs free energy decreased by 161kJmol–1 and the potential decreased by 0.019V with an increase of temperature from 20 to 80°C, which indicates that the drop in both energy and potential specifically fits the STEP-AOPs technique. Experimental results showed that the STEP-AOPs achieved a total organic carbon (TOC) removal of 95.6% for methyl orange. The TOC removal rate improved by 39.8% and the unit TOC electricity consumption decreased by 53.8% at 80°C compared with conventional methods (20°C). The mineralisation mechanism for methyl orange was a gradual shortening of the molecular chain through cleavage of the azo bond, breakdown of the benzene ring and formation of inorganic small molecules susceptible to be oxidised to non-toxic small molecules, and carbon dioxide via STEP-AOPs. The evidence shows that the STEP-AOPs is capable of mineralising azo compounds completely.

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