Removal of Arsenic from Contaminated Water by Selected Geological Natural Materials

This study investigates the efficiency of peat soil, bauxite and iron concretion to remove arsenic from contaminated water. Batch experiments were carried out to study the removal kinetics of arsenic under different pH values and in the presence of low and high concentrations of arsenic. Mini column test was carried out to investigate the removal of arsenic from contaminated water under different pore volumes. The results showed that peat soil has high specific surface area (SSA) 422 -533 m2/g compared with bauxite and iron concretion. However, iron concretion has high cation exchange capacity (CEC) 59-65 meq/100g while, peat soil and bauxite have 33-48 meq/100g and 24-33 meq/100g respectively. Batch test results present that the iron concretion is the best materials to remove arsenic from contaminated water with adsorbed amount (q) 4999 mg/kg after 48 hours shaking time. With the same shaking time, it appeared that the maximum amount of arsenic adsorbed by peat soil and bauxite are 4996 mg/kg and 4559 mg/kg, respectively. However, the mini column test results showed that iron concretion has low adsorption arsenic removal compared with bauxite and peat soil. The results showed that bauxite have maximum adsorption values with a relative concentration (Ce/Co) of 1.4*10"2 after 3 PV of infiltration. Iron concretion material had minimum adsorption with low Ce/Co value of 0.99. In general, efficient removal of arsenic was observed resulting at concentrations below the limit of 10 ^g/L in water