scholarly journals Discoloration and mineralization of a textile azo dye using a hybrid UV/O3/SBR process

2021 ◽  
Vol 11 (10) ◽  
Author(s):  
Hakimeh Mahdizadeh ◽  
Yousef Dadban Shahamat ◽  
Susana Rodríguez-Couto
Keyword(s):  
Textile Industry ◽  
Advanced Oxidation Processes ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Synthetic Dyes ◽  
Oxidation Processes ◽  
Toc Removal ◽  
Reactive Red 198 ◽  
Water And Wastewater ◽  
Ozonation Process

AbstractMost synthetic dyes are toxic and hardly biodegradable compounds that enter the environment mainly through the discharged of non-treated textile industry effluents. The present study investigated the removal of the textile monoazo dye Reactive Red 198 (RR-198) from aqueous solutions using the ultraviolet light and ozonation alone and in combination (i.e., UV/O3) followed by a Sequencing Batch Reactor (SBR). The pH (5 ≤ pH ≤ 9) and dye initial concentration (50–300 mg/L) parameters were optimized in the ozonation process at reaction time of 0–60 min. Then, TOC removal and dye discoloration percentage was compared with the O3, UV and O3/UV processes. In order to compare the performance of the SBR in dye discoloration of RR-198 and TOC removal, four types of effluent, including Raw dye, O3-pretreated dye, UV-treated dye and UV/O3-pretreated dye were separately treated in the SBR system. In the ozonation process, by increasing the pH and reducing the initial dye concentration increased the discoloration percentage. The highest dye discoloration percentage and TOC removal obtained in the hybrid UV/O3/SBR process. Combining biological systems and Advanced Oxidation Processes is an appropriate option for the decomposition of resistant pollutants and increasing the biodegradability of these compounds and is applicable in the water and wastewater industry.

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.

Application of UV-Based Advanced Oxidation Processes in Water and Wastewater Treatment

2019 ◽  
pp. 384-414 ◽  
Author(s):  
Nurazim Ibrahim ◽  
Sharifah Farah Fariza Syed Zainal ◽  
Hamidi Abdul Aziz
Keyword(s):  
Advanced Oxidation Processes ◽  
Degradation Mechanism ◽  
Advanced Oxidation ◽  
Water And Wastewater Treatment ◽  
Current Application ◽  
Principal Mechanism ◽  
Low Concentration ◽  
Oxidation Processes ◽  
Treatment Processes ◽  
Water And Wastewater

The presence of hazardous micropollutants in water and wastewater is one of the main concerns in water management system. This micropollutant exists in a low concentration, but there are possible hazards to humans and organisms living in the water. Moreover, its character that is recalcitrant to microbiological degradation makes it difficult to deal with. Advanced oxidation processes (AOPs) are efficient methods to remove low concentration micropollutants. AOPs are a set of processes consisting the production of very reactive oxygen species which able to destroy a wide range of organic compounds. The main principal mechanism in UV-based radical AOP treatment processes is the use ultraviolet light to initiate generation of hydroxyl radicals used to destroy persistent organic pollutants. Therefore, this chapter presents an overview on the principle of radical oxidant species generation and degradation mechanism by various type of UV based AOP in treating contaminants present in water and wastewater. The current application and possible improvement of the technology is also presented in this chapter.

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.

Evaluation of advanced oxidation processes for water and wastewater treatment – A critical review

2018 ◽  
Vol 139 ◽  
pp. 118-131 ◽  
Author(s):  
David B. Miklos ◽  
Christian Remy ◽  
Martin Jekel ◽  
Karl G. Linden ◽  
Jörg E. Drewes ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Critical Review ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Water And Wastewater Treatment ◽  
Oxidation Processes ◽  
Water And Wastewater

The fate of peroxyl radicals in aqueous solution

1997 ◽  
Vol 35 (4) ◽  
pp. 9-15 ◽  
Author(s):  
Clemens von Sonntag ◽  
Peter Dowideit ◽  
Fang Xingwang ◽  
Ralf Mertens ◽  
Pan Xianming ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aromatic Compounds ◽  
Advanced Oxidation Processes ◽  
Room Temperature ◽  
Oxidative Degradation ◽  
High Reactivity ◽  
Peroxyl Radicals ◽  
Oh Radical ◽  
Oxidation Processes ◽  
Water And Wastewater

The reactions of peroxyl radicals occupy a central role in oxidative degradation. Under the term Advanced Oxidation Processes in drinking-water and wastewater processing, procedures are summarized that are based on the formation and high reactivity of the OH radical. These react with organic matter (DOC). With O2, the resulting carbon-centered radicals O2 give rise to the corresponding peroxyl radicals. This reaction is irreversible in most cases. An exception is hydroxycyclohexadienyl radicals which are formed from aromatic compounds, where reversibility is observed even at room temperature. Peroxyl radicals with strongly electron-donating substituents eliminate O2.−, those with an OH-group in a-position HO2.. Otherwise organic peroxyl radicals decay bimolecularly. The tetroxides formed in the first step are very short-lived intermediates and decay by various pathways, leading to molecular products (alcohols, ketones, esters and acids, depending on the precursor), or to oxyl radicals, which either fragment by scission of a neighbouring C-C bond or, when they carry an a-hydrogen, undergo a (water-assisted) 1,2-H-shift.

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