Zein Microparticles as Versatile Adsorbents for Organic Dye Removal: Isotherms, Experimental Design, and Environmental Assessment

ABSTRACT Dye effluents are a major source of pollution of the water environment and human health. A variety of adsorbents have been used to study the removal of dyes from the aquatic environment. Adsorption is usually used as a simple and effective method among these approaches. Zein, a protein extracted from corn, can be used to easily produce nano‐ and micro‐scale particles. This study is based on using microparticles of zein as an efficient adsorbent to remove dyes from aqueous solutions. Specifically, Orange G and Crystal Violet were chosen as model dyes for this purpose. Different techniques, such as FTIR, TEM, electrophoretic mobility and dye adsorption isotherms, were used to characterise the adsorbent. A design of experiments was used to study the influence of parameters, including pH, time, ionic strength, dye concentration, adsorbent mass, dye type and centrifugation. The optimum conditions of 4.5, 5.0 min, 0.5 mol L −1 NaCl, 10 µmol L −1 , 1 mg were obtained for pH, contact time, ionic strength, dye concentration, microparticles of zein mass and centrifuge set to off, respectively. The results showed that on the fourth day 15.5% orange G and 56% crystal violet were removed.