Biopolymer Based Hydrogels for Arsenic Removal

Water contamination by arsenic has led to serious human-health hazards. Millions of people die every year in several countries of the world because of arsenic-rich groundwater. To date, adsorption by activated carbon, iron-basedadsorbents, zeolite and hydrogels have been widely used for arsenic-ion removal. Among these, adsorption by renewable resource-based hydrogels has ignited great interest because of biocompatibility, biodegradability, low cost and non-toxicity properties. This article discusses the biopolymer-based hydrogels like cellulose, chitin, pectin and chitosan for arsenic removal. It also discusses the arsenic chemistry, health hazards caused by arsenic, pros and cons of various techniques used for arsenic removal and different mechanisms involved in arsenic adsorption. Though hydrogels are capable of bringing down the arsenic level below the WHO limit, their reusability, recovery of industrially important metal ions from hydrogels and the mechanical stability of hydrogels under harsh conditions should be given more focus in future research.