Document Type : Research Paper
Authors
1
Former Graduate Student, Faculty of Agriculture, University of Tabriz, Iran
2
Assistant Professor, Faculty of Agriculture, University of Tabriz, Iran
3
Associate Professor, Faculty of Agriculture, University of Tabriz, Iran
Abstract
Since arsenic pollution is one of issues of concern about human health, especially in industrial areas, studying its immobilizing methods and effective factors is necessary. In this research, some effective factors on arsenic immobilization in soils including reaction time, pH, Iron(II), zero valent iron (ZVI ) and zeolite-Fe were studied. The soil was spiked with As (III) as sodium arsenite at 300 and 440 mg kg-1 by using pure sodium arsenite salt. Test of time and pH by using Fe (II) and ZVI were performed as batch system in spiked soil with arsenic concentration of 440 (mg kg-1), 2% of amendments during 16 hours as reaction time. The effect of concentration on the initial concentrations of 0.5, 1.5 and 2.5 percent by weight of the amendments were studied. Surveying the effect of the factors including time and pH on As (III) IE (%) using zeolite-Fe was conducted in spiked soil with arsenic concentration of 300 (mg kg-1), 0.17% Fe dosage on zeolite within 16 hours as reaction time. The effect of initial concentration of iron-loaded zeolite, on IE (%) by zeolite containing 0, 0.005, 0.017 and 0.02 mg Fe was studied. According the results, at the first 15 minutes of experiment, Fe (II)’s reaction time and As (III) IE(%) was more than ZVI, but after 16 hours efficiency of ZVI became 96.55 (%) while As (III) IE (%) by using Fe (II) was 68.2. With increasing pH (6 to 10), As (III) IE (%) by Fe (II) and zeolite-Fe had been increased while ZVI acts better at pH’s below 8. The most efficiency of Fe (II) was in its least concentration. With increasing ZVI percentage and loaded Fe on zeolite, IE (%) had increased, too. Zeolite-Fe showed a good rate and efficiency, so that immobilized a large part of As (III) in the first 15 minutes of reaction time.
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