MODELING AND SIMULATION OF ARSENIC REMOVAL FROM WATER IN PACKED BED COLUMN USING LATERITE SOIL

Abstract

Arsenic contamination in groundwater of many countries such as Argentina, Bangladesh, Cambodia, Canada, Chile, China, Germany, Hungary, India, Mexico, Mongolia, Myanmar, Nepal, Pakistan, Romania, Thailand, USA, Vietnam, etc. and long term consumption of such contaminated groundwater by common people has caused a numerous health disorders around the world. A variety of technologies have been developed for the treatment of arsenic in water. The major technologies include precipitation—coagulation, membrane separation, ion exchange and adsorption. Among these technologies, adsorption is a cost-effective and user friendly technique for arsenic removal from water, and it can be used in small scale house-hold units. Recently, natural solids are also used as adsorbents for arsenic removal as their elemental compositions are similar with the synthetic adsorbents used. Natural adsorbents help in reducing the time and cost for preparing the material. With the understanding that the natural presence of Fe(III) and Al(III) in laterite soil may open up the possibility of laterite soil to be used as a potential adsorbent for arsenic removal, the systematic study to evaluate the performance of laterite soil as an adsorbent for As(III) was undertaken. The performance of a fixed bed column for the removal of As(III) from aquatic environment was studied. Laterite soil was used as the adsorbent material. The column with 2.5 cm diameter, different bed heights such as 15 cm, 30 cm, 45 cm and 60 cm, and As(III) bearing (conc. 0.2 mg/1) water at a flow rate of 7.75 ml/min. Aspen ADSIM was employed for the determination of different parameters like height of exchange zone, adsorption rate, time required for exchange zone to move, and the adsorption capacity. Effect of flow rate, effect of pressure and effect of initial concentration was studied and simulated this model using Aspen ADSIM.