adsorption of arsenic from aqueous solutions by iron filings and the effect of magnetic field

aims: arsenic contamination of natural water resources has become an important environmental problem in the world. the adsorption method by iron filings adsorbent or zero-valent iron was used. the study aimed to evaluate the efficiency of iron filings in arsenite removal from polluted water and to investigate the effect of magnetic field on the process. materials & methods: this interventional study was conducted in synthetically polluted water samples with certain arsenic concentrations. with regard to the initial arsenic concentration (0.5 and 2mg/l), iron filings dosages (0, 2.5 and 5g/l), contact times (5, 10 and 15min) and considering the samples before and after magnetic column, 108 samples were prepared. data was analyzed by paired sample t and one-way anova tests. findings: the highest mean of removal efficiency at the initial arsenic concentration of 0.5mg/l was seen at the iron filings of 5g/l and 10min contact time (87.7±10.0) and at the initial arsenic concentration of 2mg/l was seen at the iron filings of 5g/l and 15min contact time (86.3±8.4). at the initial arsenic concentration of 0.5mg/l, magnetic field increased the removal efficiency of arsenite at the iron filings dosage of 0g/l and decreased it at the iron filings dosage of 5g/l. the same happened at the initial arsenic concentration of 2mg/l. conclusion: arsenic is reduced from the water samples with the iron filings dosage of 5g/l at natural ph. magnetic field increases the arsenic removal efficiency in the absence of the iron filings and decreases the arsenic removal efficiency in the presence of the iron filings.