Development of biopolymeric hybrid composites for selective chromium adsorption

Abstract

Water is one of the fundamental resources available for existence of all the living organisms. The quality of water gets affected by various pollutants such as heavy metals, toxic anions, dyes, etc. These pollutants enter into water sources from various industries and domestic wastes. Chromium is one of the common heavy metals utilized in various industries like tanneries, pigments, electroplating, paper and battery manufacture. It is non-biodegradable and easily soluble which leads to various illnesses on the living organisms. Hence, chromium remediation is needed to bring the safe drinking water. Several technologies have been investigated for chromium removal and among them adsorption process possess many features such as high selective, low-cost and easily operated technique. Different types of adsorbents such as carbon based materials, clay materials, natural minerals, metal oxides, polymeric materials, biomass and coagulants were used for Cr(VI) removal. But, the separation of these adsorbents would be difficult from aqueous solution after their usage due to them create pressure drop during filtration. To remove such technical problems, the hybrid polymeric composites were synthesized by incorporating inorganic materials into polymeric matrix. Although, biosorption is an environmental sound technique, hence bioadsorbents such as alginate, cellulose, chitosan, etc., are utilized for the synthesis of new class of hybrid biocomposites/beads. The hybrid biocomposites possess many advantages like biodegradable, biocompatible and non-toxic. Layered double hydroxides (LDHs) like hydrocalumite and hydrotalcite indicates its selectivity for Cr(VI) removal. Hence, these LDHs were doped into various biopolymeric composites to carry out their efficient Cr(VI) adsorption capacities. Nevertheless, the quick separation of adsorbent from aqueous solution is a challenging task. Magnetic particles imprinted biopolymeric composites were prepared for Cr(VI) removal and the magnetic biopolymeric composites were easily removed from aqueous solution using an external magnetic field. newline