Arsenic oxidation by UV radiation combined with hydrogen peroxide

2010 ◽  
Vol 61 (2) ◽  
pp. 339-344 ◽  
Author(s):  
S. Sorlini ◽  
F. Gialdini ◽  
M. Stefan

Arsenic is a widespread contaminant in the environment around the world. The most abundant species of arsenic in groundwater are arsenite [As(III)] and arsenate [As(V)]. Several arsenic removal processes can reach good removal yields only if arsenic is present as As(V). For this reason it is often necessary to proceed with a preliminary oxidation of As(III) to As(V) prior to the removal technology. Several studies have focused on arsenic oxidation with conventional reagents and advanced oxidation processes. In the present study the arsenic oxidation was evaluated using hydrogen peroxide, UV radiation and their combination in distilled and in real groundwater samples. Hydrogen peroxide and UV radiation alone are not effective at the arsenic oxidation. Good arsenic oxidation yields can be reached in presence of hydrogen peroxide combined with a high UV radiation dose (2,000 mJ/cm2). The quantum efficiencies for As(III) oxidation were calculated for both the UV photolysis and the UV/H2O2 processes.

1995 ◽  
Vol 31 (5-6) ◽  
pp. 131-134 ◽  
Author(s):  
Ritva L. Rajala-Mustonen ◽  
Helvi Heinonen-Tanski

Chlorine and its derivatives are no longer regarded as acceptable disinfectants of water because of compounds they form with organic material in water. These compounds have been proved to be mutagenic and carcinogenic to man. Alternative disinfectants like UV radiation and ozonization are regarded as less harmful disinfectants of microorganisms in water. In the present study the effect of UV radiation alone and together with hydrogen peroxide, and ozone treatment on the inactivation of coliphages in tap water were studied. Two phage types, DNA- and RNA-phages were seeded into tap water and exposed to these disinfectants in batch experiments. The inactivation of phages was determined as a reduction of phage titer as a function of contact time. Disinfection with ozone proved to inactivate coliphages more rapidly than UV light or UV light together with hydrogen peroxide (H2O2). After two minutes exposure time the reduction in phage titer was from 6 to 8 log units with ozone while with UV light or UV with H2O2 the reduction was from three to four log units. According to these results ozonization seemed to be more efficient disinfectant than UV light radiation.


Entecho ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 1-5
Author(s):  
Tamara Pacholská ◽  
Pavla Šmejkalová

Intenzívne používanie pesticídnych látok spôsobilo na mnohých miestach vážne problémy v ekosystéme, najmä čo sa týka vodných zdrojov, kam sa tieto látky dostávajú. Keďže klasickou vodárenskou technológiou nie je možné pesticídy z vody odstraňovať, nachádzajú sa tak tieto látky v nadlimitných koncentráciách v pitných vodách. Preto je nutné navrhnúť technológiu, ktorá bude v ich odstraňovaní účinná. Ako vhodné sa ukazujú pokročilé oxidačné procesy (AOPs) v kombinácii s granulovaným aktívnym uhlím (GAU). Cieľom tohto experimentu bolo porovnať účinok ozonizácie a pokročilých oxidačných procesov, z ktorých sa overovala kombinácia ozónu s UV žiarením (O3 + UV) a ozónu s peroxidom vodíka (O3 + H2O2) s následnou sorpciou na GAU. Abstract (en) Intensive use of pesticides has caused serious problems in the ecosystem in many places, especially in terms of the water resources to which pesticides enter. It is not possible to remove pesticides from water using conventional water supply technology, so these substances are found in above-limit concentrations in drinking water. Therefore, it is necessary to design a technology that will be effective in removing them. Advanced oxidation processes (AOPs) in combination with granular activated carbon (GAU) prove to be suitable. The aim of this experiment was to compare the effect of ozonation and advanced oxidation processes, which verified the combination of ozone with UV radiation (O3 + UV) and ozone with hydrogen peroxide (O3 + H2O2) followed by sorption on GAU.


2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari

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.


2001 ◽  
Vol 44 (5) ◽  
pp. 53-60 ◽  
Author(s):  
C.A. Martín ◽  
O.M. Alfano ◽  
A.E. Cassano

Sometimes, provision of water for domiciliary consumption faces the problem of natural contamination originated by the presence of organic substances such as humic or fulvic acids. Very often, after conventional sanitary treatments this water exhibits a persistent yellowish coloration that affects its use. Moreover, these substances may act as precursors of tri-halomethanes formation during pre-desinfection with chlorine. This paper presents, with a simplified mechanistic approach, the intrinsic reaction kinetics of natural water decolorization employing UV radiation and hydrogen peroxide. The main variables for the model are: contaminant concentration expressed as TOC, hydrogen peroxide concentration and the photon absorption rate.


2013 ◽  
Vol 39 (3) ◽  
pp. 79-91 ◽  
Author(s):  
Natalia Lemańska-Malinowska ◽  
Ewa Felis ◽  
Joanna Surmacz-Górska

Abstract The photochemical degradation of the sulfadiazine (SDZ) was studied. The photochemical processes used in degradation of SDZ were UV and UV/H2O2. In the experiments hydrogen peroxide was applied at different concentrations: 10 mg/dm3 (2.94*10-4 M), 100 mg/dm3 (2.94*10-3 M), 1 g/dm3 (2.94*10-2 M) and 10 g/dm3 (2.94*10-1 M). The concentrations of SDZ during the experiment were controlled by means of HPLC. The best results of sulfadiazine degradation, the 100% removal of the compound, were achieved by photolysis using UV radiation in the presence of 100 mg H2O2/dm3 (2.94*10-3 M). The determined rate constant of sulfadiazine reaction with hydroxyl radicals kOH was equal 1.98*109 M-1s-1.


1992 ◽  
Vol 27 (1) ◽  
pp. 23-42 ◽  
Author(s):  
William H. Glaze ◽  
Fernando Beltran ◽  
Tuula Tuhkanen ◽  
Joon-Wun Kang

Abstract Advanced oxidation processes (AOPs) have been defined as near-ambient temperature processes that involve the generation of highly reactive radical intermediates, especially the hydroxyl radical. These processes show promise for the destruction of hazardous organic substances in municipal and industrial wastes, in drinking water and in ultrapure water. Three types of AOPs are considered in this paper: catalyzed decomposition of ozone; ozone with hydrogen peroxide (Peroxone); and photolysis of hydrogen peroxide with ultraviolet radiation. Kinetic models for these processes are being developed based on known chemical and photochemical principles. The models take into account measured effects of radical scavengers such as bicarbonate; dose ratios of the oxidants or UV intensity; pH; and the presence of generic radical scavengers. The models are used to discuss two cases: oxidation of parts-per-million levels of nitrobenzene with ozone, Peroxone and peroxide/UV and oxidation of naphthalene and pentachlorophenol with peroxide/UV.


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