Patents

Present invention deals with cost-effective surface-modified zeolite materials developed from commercial zeolites and flyash-based zeolites by treating with surface modifiers like hexadecyltrimethyl ammonium bromide (HDTMA-Br). The formation of zeolitic materials with anionic characteristics requires treatment with a surfactant with initial concentrations greater than its critical micelle concentration (CMC).The sorption of oxyanions on the surfactant-modified zeolite (SMZ) is attributed to surface complexation and surface precipitation. Incorporation of metal ions on SMZ showed improved anion uptake for dearsenification of water due to synergistic effects and is able to meet the stringent target of 10 ppb of As on potable water being adopted by most countries. High selectivity, faster kinetics and high adsorption capacity ensures cost effectiveness of this product as compared to other low-cost products for dearsenification. Zeolite analogues with anionic characteristics have been developed for their applications for removal of arsenic from water. The material developed can also be used to remove other anions like chromium and selenium.