8 - Lignocellulosics as adsorbents for removal of dyes from water

Abstract

Drinking water is depleting rapidly due to population growth, industrialization, and urbanization. Water resources are contaminated everyday by effluents of industries such as dyeing, textile, pulp tanner, paper, paint, and pigments. This affects considerably the ecosystems and the health of living beings. One of the most important environmental pollutants is dyes present in large amounts in the wastewater from various industrial activities. Various techniques such as precipitation, aerobic, and anaerobic microbial degradation, ultrafiltration, coagulation/flocculation, electrochemical treatments, advanced oxidation processes, reverse osmosis, and adsorption have been used for the removal of dyes from aqueous solutions. Out of all the methods, the adsorption technique of removal of dyes from aqueous solution is the most efficient and economical. Lignocellulosic biomass (agricultural wastes) is abundantly available, economical, and highly selective and therefore, detailed applications of these materials for removal of dyes have been described in this chapter. The efficiency of adsorption depends on the type of dye and type of lignocellulosic biomass. Different types of dyes with their structure and toxic effects and different types of agricultural wastes have been described. Various parameters and regeneration ability of lignocellulosic biomass for the removal of dyes have been discussed in this chapter. The effect of temperature, adsorbent dosage, pH, and contact time has also been briefly described.