Study involving removal of azo dye Direct Orange 34 by adsorption in zeolite–clay system

Abstract

Recently, dyes have procured a wide range of application in the textile industry. These organic compounds possess toxic agents and act as water pollutants. Such dyes can be extracted by adsorption to prevent water pollution. The present work proposes removal of azo dye Direct Orange 34 from the aqueous solution using mixtures of sodalite zeolite (Si/Al ratio 2.5) and clay (vermiculite in 1.0, 2.5, 5.0 g). The methodology involves a system with different stages of separation, considering specified retention time (72, 48, 24, 12, 6 h) of adsorbate and dye concentrations (100, 50, 25, 10, 5 mg/L). The zeolite–vermiculite mixture has a high potential of dye removal due to extensive surface area and porosity with excellent cation exchange capacity conferring its adsorbent property. High concentrations (50 and 100 mg/L) and longer retention times than 48 h results in 50% removal of dyes, whereas a low concentration level (25, 10, 5 mg/L) increases the removal efficiency (74%). Henceforth, the experiment concluded that the zeolite–clay mixtures are capable of azo dye extraction.