interfering effects of iron(ii) and arsenic(iii) in the cerium-based adsorption technology in bangladesh

Arsenic (as) contamination in the groundwater of bangladesh is one of the major public health concerns. it has become a challenge to remove as from groundwater and a great deal of efforts employed in this regards with limited success. cerium oxide is one of the important medias of arsenic removal techniques. nine units of cerium-based arsenic technology were tested with seven different well waters in five hydro-geological areas in bangladesh. interestingly, the same technology showed variable results in terms of as removal performance from well water. therefore, this study aimed to investigate the reasons behind the variant performance of the as removal technology. the studied wells were contaminated with a range of 283 to 873 μg/l of arsenic, 0.35 to 10.4 mg/l of iron, 0.29 to 6.83 mg/l of phosphate, 32.5 to 49.5 mg/l of silicate, 0.08 to 0.25 mg/l of sulfate and ph range was 7.11 to 7.65. the cerium-based as removal technology consistently produced as safe water from three wells containing more than 80% as (iii) of total arsenic (as) and >3 mg/l of iron and reduced as concentration to below 50 μg/l consistently but failed at other four wells containing less than 75% as (iii) of tas and <3.6 mg/l of iron. the test results confirm that the main reason of poor performance was lower concentration of as (iii) and iron in groundwater. therefore, before choosing a technique for as removal should follow the as speciation in the water system.