Arsenic removal from drinking water with conventional and modified adsorbents: the factorial design of experiments

Many areas of Pakistan are facing the problem of arsenic concentrations in underground water exceeding WHO limits. The kinetics, isotherm, and column efficiency of arsenic removal were tested for the following four adsorbents: alumina, iron-doped alumina (FA), and iron- and aluminum-doped brick particles (BF and BA). Alumina removed 85-99% arsenic in batch and continuous processes, respectively, with 1.22mg/g adsorption capacity. FA had a higher adsorption capacity of up to 3.03mg/g with a longer time to attain equilibrium. BF and BA had adsorption capacities of 0.16 and 0.02mg/g, respectively, and took longer time to attain equilibrium. Statistical factorial design 2(4) showed that the variables were significant and optimized the process.