scholarly journals Evaluation of Efficacy of Anionic Surfactant Degradation in the Presence of Concomitant Impurities of Natural Waters

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yuliya Shvadchina ◽  
Vera Vakulenko ◽  
Elena Alekseenko ◽  
Anatoliy Sova
Keyword(s):  
Anionic Surfactant ◽  
Photocatalytic Oxidation ◽  
Natural Waters ◽  
Uv Treatment ◽  
River Waters ◽  
Oxidation Processes ◽  
Maximum Reduction ◽  
Toc Removal ◽  
Alkylbenzene Sulfonate ◽  
Surfactant Degradation

The efficacy of anionic surfactant—sodium alkylbenzene sulfonate (ABS) degradation in the river waters and model solutions containing humic acid by various oxidation processes has been compared. The most effective method is photocatalytic ozonation (O3/TiO2/UV) which ensures maximum reduction of ABS concentration (94%-95% over 20–30 min) from ~5 mg/dm3to values not exceeding the MPC (<0.5 mg/dm3) and the highest degree of total organic carbon (TOC) removal (up to 74%) at the lowest values of specific ozone consumption per 1 mg/dm3of TOC compared to ozonation and O3/UV. Photocatalytic oxidation with air oxygen (O2/TiO2/UV) and O3/UV treatment provides a smaller decrease in ABS concentrations (86%–93% and 71%–87% within 20–30 min, resp.) and significantly lowers TOC removal (up to 57% and 47%, resp.). Ozonation and UV irradiation, used separately, are inefficient methods for ABS degradation (<40%), and for TOC removal (<15%).

scholarly journals Tetracycline Degradation in the UV-heterogeneous Fenton-like System With BiFeO3 Catalyst

2021 ◽  
Author(s):  
Yongwei Jiang ◽  
Chao Xing ◽  
Yue Chen ◽  
Jing Shi ◽  
Sheng Wang
Keyword(s):  
Photocatalytic Oxidation ◽  
Advanced Oxidation Processes ◽  
Degradation Process ◽  
Heterogeneous Fenton ◽  
Oxidation Processes ◽  
Toc Removal ◽  
Secondary Pollution ◽  
Tetracycline Degradation ◽  
Positive Holes ◽  
Oxidation System

Abstract Surplus tetracycline (TC) in the water body causes damage to the ecology balance and human health. Therefore, an efficient strategy was proposed, namely, the UV-heterogeneous Fenton-like system with BiFeO3 (BFO) catalyst, to eliminate TC pollution. This work successfully integrated the photocatalytic oxidation system with the heterogeneous Fenton-like system, cooperating with the photolysis of H2O2. These coupled effects could boost the reduction of Fe (Ⅲ) to Fe (Ⅱ) and depress the recombination of photogenerated charges, further promoting the generation of reactive species, and ultimately facilitating the TC degradation and mineralization. The catalytic of the prepared BFO was stable with no secondary pollution, and BFO could be recovered by an extra magnet to reuse. Compared with other advanced oxidation processes, this system showed an outstanding performance in TC degradation and mineralization, and TC and TOC removal efficiencies could reach 100% and 74.92%, respectively. Moreover, the possible mechanisms for TC degradation involved that TC was degraded by oxidation species generated by the synergistic effect in this system, such as superoxide radicals (·O- 2), hydroxyl radicals (·OH), and positive holes (h+). Intermediate products in the TC degradation process mainly were products at m/z=459, m/z=445, and m/z=134.

scholarly journals Magnetic iron oxide/clay nanocomposites for adsorption and catalytic oxidation in water treatment applications

2020 ◽  
Vol 18 (1) ◽  
pp. 1148-1166
Author(s):  
Ganjar Fadillah ◽  
Septian Perwira Yudha ◽  
Suresh Sagadevan ◽  
Is Fatimah ◽  
Oki Muraza
Keyword(s):  
Iron Oxide ◽  
Water Treatment ◽  
Photocatalytic Oxidation ◽  
Low Cost ◽  
Synthesis Method ◽  
Chemical Oxidation ◽  
Magnetic Iron Oxide ◽  
Oxidation Processes ◽  
Recent Developments ◽  
Physical And Chemical

AbstractPhysical and chemical methods have been developed for water and wastewater treatments. Adsorption is an attractive method due to its simplicity and low cost, and it has been widely employed in industrial treatment. In advanced schemes, chemical oxidation and photocatalytic oxidation have been recognized as effective methods for wastewater-containing organic compounds. The use of magnetic iron oxide in these methods has received much attention. Magnetic iron oxide nanocomposite adsorbents have been recognized as favorable materials due to their stability, high adsorption capacities, and recoverability, compared to conventional sorbents. Magnetic iron oxide nanocomposites have also been reported to be effective in photocatalytic and chemical oxidation processes. The current review has presented recent developments in techniques using magnetic iron oxide nanocomposites for water treatment applications. The review highlights the synthesis method and compares modifications for adsorbent, photocatalytic oxidation, and chemical oxidation processes. Future prospects for the use of nanocomposites have been presented.

Coupling membrane separation and photocatalytic oxidation processes for the degradation of pharmaceutical pollutants

2013 ◽  
Vol 47 (15) ◽  
pp. 5647-5658 ◽  
Author(s):  
F. Martínez ◽  
M.J. López-Muñoz ◽  
J. Aguado ◽  
J.A. Melero ◽  
J. Arsuaga ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Membrane Separation ◽  
Oxidation Processes ◽  
Pharmaceutical Pollutants

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.

Treatment of pharmaceutical wastewater by combination of electrocoagulation, electro-fenton and photocatalytic oxidation processes

2020 ◽  
Vol 8 (3) ◽  
pp. 103777 ◽  
Author(s):  
Gizem Başaran Dindaş ◽  
Yasemin Çalışkan ◽  
Emin Ender Çelebi ◽  
Mesut Tekbaş ◽  
Nihal Bektaş ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Pharmaceutical Wastewater ◽  
Oxidation Processes

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.

Location of photocatalytic oxidation processes on anatase titanium dioxide

2017 ◽  
Vol 7 (2) ◽  
pp. 441-451 ◽  
Author(s):  
Xuan Hao Lin ◽  
Yijia Miao ◽  
Sam Fong Yau Li
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Oxidation ◽  
Detailed Mechanism ◽  
Oxidation Processes ◽  
Degradation Processes

The detailed mechanism of photocatalytic oxidation processes on the TiO2 surface is still not completely clear, particularly the location of degradation processes.

Factors influencing the inorganic speciation of trace metal cations in fresh waters

1999 ◽  
Vol 50 (4) ◽  
pp. 367 ◽  
Author(s):  
Jonathan P. Kim ◽  
Keith A. Hunter ◽  
Malcolm R. Reid
Keyword(s):  
Natural Waters ◽  
Major Ions ◽  
Divalent Cations ◽  
Ion Composition ◽  
High Ph ◽  
River Waters ◽  
Inorganic Complexes ◽  
Effects Of Ph ◽  
Ph Range ◽  
Inorganic Speciation

The effects of pH and major ion composition on the chemical speciation of the divalent cations of Co, Ni, Cu, Zn, Pb and Cd have been examined after consideration of the available thermodynamic database for solution complexes of these ions. Calculations were made for two model river waters representing the 1% and 99% extremes in composition of global river waters. The results show that inorganic speciation behaviour is of two characteristic types: (a) Cu, Zn and Co are dominated by bis-hydroxy- complexes at high pH and show the greatest reduction in the fraction of free aquo ion with increasing pH; (b) Pb, Ni and Cd are dominated by carbonato- complexes at high pH and show a more gradual decrease in the fraction of free aquo ion with increasing pH. For Cu, Pb and Ni significant fractions of the labile forms of these metal ions are present as inorganic complexes in the pH range of most natural waters, whereas for Zn, Co and Cd this is true only at moderately high pH (pH >7.5). Complexing with the major ions SO42– and Cl– is important only at low pH in river waters of high ionic strength.

Determination of the aluminium complexing capacity of fulvic acids and natural waters, with examples from five New Zealand rivers

1996 ◽  
Vol 47 (1) ◽  
pp. 11 ◽  
Author(s):  
DJ Hawke ◽  
KJ Powell ◽  
JE Gregor
Keyword(s):  
Reaction Time ◽  
Natural Waters ◽  
Fulvic Acids ◽  
Operational Definition ◽  
Experimental Conditions ◽  
River Waters ◽  
Complexation Capacity ◽  
Complexing Capacity ◽  
Definition Of

An FIA technique with 7 s reaction time was used to analyse free plus labile Al in fulvic acid (FA) solutions and natural waters at pH 4.7, without the need for separation procedures. Titrations of these solutions using incremental pH or total Al were used to determine pH binding curves or estimates of the 'kinetic' Al complexation capacity (Al-CCk) respectively. The operational definition of Al-CCk relates to the capacity of a humic substance or natural water to bind Al through a 7-s FIA reaction time under defined experimental conditions of chromophore (CAS) concentration, ionic strength, and pH. Both Al binding strength and complexation capacity were greater than the corresponding Cu-CC (ISE) values. The Al-CCk measurements at pH 4.7 were 710 μmol Al g-1 v. 590 μmol Cu g-1. Al-CCk results (pH 4.7) were higher for soil FA (710 μmol g-1) than for aquatic FA (390 μmol g-1). Al-CCk results (pH 4.7) for five unfiltered river waters from different catchments gave results in the range 6.5-9.8 μmol Al L-1. The differences between total (natural) Al in the samples and Al-CCk were between 2.7 μM and 8.6 μM. Filtration experiments identified fractionation patterns between total (natural) Al and the fraction of Al-CCk not utilized. The Al titration of alginate, another component of natural organic matter, is reported.

Interactions of hypochlorite ion and humic acid: photolytic and photocatalytic pathways

2001 ◽  
Vol 44 (5) ◽  
pp. 205-210 ◽  
Author(s):  
D. Gonenç ◽  
M. Bekbolet
Keyword(s):  
Humic Acid ◽  
Reaction Kinetics ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Order Reaction ◽  
First Order Reaction ◽  
Acid Oxidation ◽  
First Order ◽  
Toc Removal

Photolytic and photocatalytic interactions of hypochlorite ion and humic acid are investigated under various conditions. Humic acid oxidation by aqueous chlorine under dark conditions are expressed in terms of first order reaction kinetics. Upon irradiation (300 nm &lt; λ &lt; 400 nm), photolysis of aqueous chlorine affect the removal efficiency of humic acid via oxidation. TiO2 sensitised photocatalytic oxidation conditions reveal an increase in the TOC removal rate of humic acid in the presence of aqueous chlorine. Under the specified conditions, increasing the photocatalyst loading up to 1.0 mg/mL markedly increase the TOC removal rate.

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