Zeolite-based adsorbent from alum sludge residue for textile wastewater treatment

Abstract

Highly efficient low-cost alum sludge-based sorbents, (termed as AS-Sorbents), derived from alum sludge by-product waste have shown a significant potential for treating wastewaters contaminated by textile dyes. Their application for wastewater treatment can be termed as industrial ecology approach. X-ray diffraction and scanning electron microscope were used to investigate the structural and morphological properties of these sorbents (AS, AS400, AS600, AS800). The results revealed the presence of the highly efficient adsorbent, zeolite in AS400. The experimental data revealed that AS-Sorbents exhibited a reasonable textile dye removal from real jeans dying effluent. The highest removal rate was corresponding to AS400 due to the presence of graphite and zeolite. Compared to the commercially available silica gel (Sgel) and activated carbon (Norit), AS-Sorbents are exhibited a superior removal rate of Procion Blue dye from textile effluent. The adsorption efficiency is in the order of AS400 ≫ AS > AS600 > AS800 > Norit > Sgel. The adsorption matrix was well fitted by Langmuir isotherm and followed second-order kinetic model; the maximum monolayer adsorption capacity was 6.5 mg/g. Thermodynamic parameters show that the process follows the physical adsorption matrix with a spontaneous and exothermic nature.