The adsorption of arsenic (V) by iron (Fe2O3) and aluminum (Al2O3) oxides
Arsenic(As), one of most toxic contaminants found in water, is well known to have adverse effects on human health, such as skin cancer. The consumption of arsenic contaminated water has led to human health crises in many countries such as Bangladesh, China and even the western USA. The new EPA standard for arsenic in drinking water is 10 mug/L, and many smaller drinking water treatment plants are in need of additional treatment to achieve this. Recently, many researchers have being trying to find inexpensive and disposable adsorbents for many small-scale water systems or individual ground wells, which are used in most arsenic endemic areas. The adsorption of As(V) using iron and aluminum oxides has been considered as one of the most effective small-scale techniques for arsenic removal;Two types of nonporous adsorbents were used in this dissertation: iron oxide (Fe2O3) from a byproduct of the steel industry, and aluminum oxide (Al2O3) as a chemical powder. Due to their fast adsorption of As(V) anions and low cost, (Fe2O 3) and Al2O3 were found to be good and inexpensive adsorbents in lowering As(V) initial concentration in drinking water at a lower pH (< 7). In the presence of competing ions, the adsorption of As(V) on (Fe2O3) was decreased by selenium(IV), vanadium(V), phosphate and silica, while that on Al2O3 was reduced by these same ions, and also sulfate. Phosphate anion is the most competitive ion on both (Fe2O3) and Al2O 3. Comparing the cost and adsorption capacity of As(V) in the presence and absence of competing solutes, (Fe2O3) is the more appropriate adsorbent for As(V) removal from drinking water than Al2 O3.