Zein/EDTA/chlorophyll/nano-clayBiocomposite Sorbent; Studying Physicochemical Properties and Ability to Remove Industrial Wastewater Contaminants

Abstract

In this study, a composite biosorbent of zein/ethylene diamine tetraacetic acid /chlorophyll/nano-clay (Ze/EDTA/Chl/Clay) was prepared. Thickness, mechanical properties (tensile strength and strength to breaking point), ability to reduce water hardness, water solubility, water absorption, antioxidant activity and moisture content of prepared biosorbent were studied. SEM, FTIR, XRD and TGA techniques were used to investigate the physicochemical properties and structure of the prepared biosorbent. Optimal biosorbent was selected using statistical methods and used to remove chemical contaminants from industrial wastewater in Urmia (Iran). For this purpose, total heavy metals (THM), total hardness, nitrate, nitrite, COD and BOD, TDS and salinity of industrial wastewater before and after biosorbent treatment were investigated. The results confirmed the homogeneous and cohesive structure of different zein adsorbents. FTIR results showed physical and electrostatic interactions between composite components. Nanoclay increased the thermal stability of the biosorbent. Chlorophyll and EDTA increased the biosorbent ability to absorb water and reduce the total hardness of the water. Clay nanoparticles increased the tensile strength of the biosorbent and chlorophyll and EDTA increased the biosorbent ductility. Under optimal wastewater treatment conditions, Ze/EDTA/Chl/Clay biosorbent was recognized as the best adsorbent. The use of ultrasound in wastewater treatment had a good effect. Under optimal conditions, 57.5% of THM and 67% of nitrate were removed from the wastewater. By comparing the ability of chlorophyll-containing biosorbents (Ze/Chl and Ze/EDTA/Chl/Clay) to remove nitrite and nitrate, it was found that these biosorbents have a very high selectivity in nitrate removal compared to nitrite.