Reduction of pentavalent and trivalent arsenic by TiO2-photocatalysis: An innovative way of arsenic removal

2014 ◽  
pp. 61-80
Keyword(s):  
Arsenic Removal ◽  
Trivalent Arsenic ◽  
Tio2 Photocatalysis

Application of Monoclinic Bismuth Vanadate in Photooxidation of Arsenic-Polluted Water

2020 ◽  
Vol 63 (6) ◽  
pp. 1649-1655
Author(s):  
Miaomiao Chen ◽  
Yi Li ◽  
Hong Pan ◽  
Jiuwei Teng ◽  
Ganesh Bora ◽  
...  
Keyword(s):  
Visible Light ◽  
Arsenic Removal ◽  
Inorganic Arsenic ◽  
Bismuth Vanadate ◽  
Light Irradiation ◽  
Polluted Water ◽  
List Type ◽  
Trivalent Arsenic ◽  
Keywords Arsenic ◽  
Pentavalent Arsenic

HighlightsPhotooxidation of trivalent arsenic to pentavalent arsenic was catalyzed by s-m BiVO4 under visible light irradiation.The roles of catalyst, light, and oxygen were investigated.The photooxidation mechanism was studied, and a possible reaction route is proposed.Abstract. Oxidation is a necessary step for inorganic arsenic removal. In this study, monoclinic bismuth vanadate (BiVO4) was synthesized to photooxidize trivalent arsenic to pentavalent arsenic in water in the presence of light and oxygen. Light irradiation initiates photooxidation after physical absorption of arsenite on BiVO4. Addition of oxygen slightly improved the photooxidation efficiency. Photooxidation parameters were optimized; 2.6 mM of BiVO4 synthesized at pH 2 was effective to photooxidize 0.1 M of arsenite in alkaline solution, and 99.8% removal of trivalent arsenic was achieved with a photooxidation efficiency of 85.5%. Photooxidation by BiVO4 might be initiated by hydroxyl radicals resulting from irradiation by visible light. Appropriate BiVO4 morphology and alkalinity of the reaction mixture facilitated photooxidation. Keywords: Arsenic, BiVO4, Photooxidation, Speciation.

IRON OXIDES FROM ELECTROFILTER ASH FOR WATER TREATMENT (ARSENIC REMOVAL)

2009 ◽  
Vol 8 (4) ◽  
pp. 895-900 ◽  
Author(s):  
Ionel Balcu ◽  
Adina Segneanu ◽  
Marius Mirica ◽  
Mirela Iorga ◽  
Catalin Badea ◽  
...  
Keyword(s):  
Water Treatment ◽  
Iron Oxides ◽  
Arsenic Removal

As(III) Removal by Dynamic Adsorption onto Amberlite XAD7 Functionalized with Crown Ether and Doped with Fe(III) Ions

2019 ◽  
Vol 70 (7) ◽  
pp. 2330-2334
Author(s):  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Narcis Duteanu ◽  
Corneliu Mircea Davidescu ◽  
Iosif Hulka ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Fixed Bed ◽  
World Health ◽  
Arsenic Content ◽  
Arsenic Adsorption ◽  
Stage Of Development ◽  
Wide Range ◽  
Health Organization

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

Superior co-catalysis by bimetallic nanostructure for TiO2 photocatalysis

2020 ◽  
Vol 01 ◽  
Author(s):  
Bonamali Pal ◽  
Anila Monga ◽  
Aadil Bathla
Keyword(s):  
Visible Light ◽  
Catalytic Performance ◽  
Transition Metal Catalysts ◽  
Core Shell ◽  
Structural Morphology ◽  
Tio2 Photocatalysis ◽  
Co Catalysts ◽  
Bimetallic Nanocomposites ◽  
Bimetallic Nanostructure ◽  
Bimetallic Nanostructures

Background:: Bimetallic nanocomposites have currently gained significant importance for enhanced catalytic applications relative to monometallic analogues. The synergistic interactions modified electronic and optical properties in the bimetallic (M1@M2) structural morphology e.g., core-shell /alloy nanostructures resulted in a better co-catalytic performance for TiO2 photocatalysis. Objective:: Hence, this article discusses the preparation, characterization, and co-catalytic activity of different bimetallic nanostructures namely, Cu@Zn, Pd@Au, Au@Ag, and Ag@Cu, etc. Method:: These bimetallic co-catalysts deposited on TiO2 possess the ability to absorb visible light due to surface plasmonic absorption and are also expected to display the new properties due to synergy between two distinct metals. As a result, they reveal the highest level of activity than the monometal deposited TiO2. Result:: Their optical absorption, emission, charge carrier dynamics, and surface structural morphology are explained for the improved photocatalytic activity of M1@M2 loaded TiO2 for the hydrogenation of certain organic compounds e.g., quinoline, crotonaldehyde, and 1,3-dinitrobenzene, etc. under UV/ visible light irradiation. Conclusion:: It revealed that the use of bimetallic core@shell co-catalyst for hydrogenation of important industrial organics by M1@M2-TiO2 nanocomposite demonstrates beneficial reactivity in many instances relative to conventional transition metal catalysts.

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