Journey from ceramic waste to highly efficient toxic dye adsorption from aqueous solutions via one-pot synthesis of CaSO4 rod-shape with silica

Abstract

Fine calcium oxide (CaO) which is the main component in the fine lime and considered as a waste byproduct from the steel manufacturing industry is converted into a potential composite to be used as an adsorbent. A facile and simple impregnation between CaO and silica in the presence of H2SO4 is utilized to achieve a one-step synthesis of a highly efficient CaO-based rod-shape composite with silica (CRCS). The suitability of using this composite in hazardous crystal violet (CV) cationic dye removal from aqueous solution was evaluated in series batch experiments. The synthesized composite was characterized using various techniques including XRD, SEM, TEM, EDX, FT-IR, and Raman to determine the adsorbent physicochemical properties. Influences of various operating parameters such as contact time, initial dye concentration, adsorbent dosage, agitation speed, initial pH, and reaction temperature were examined. The results of the experimental data well fitted Langmuir and the pseudo-first-order kinetic model. Based on the thermodynamic parameters, the sorption of CV onto CRCS is a spontaneous and endothermic process. The prepared CRCS also exhibited easily regeneration and recycling at least for ten adsorption–desorption runs. This study offers new insights into promising waste management technology that is efficiently applied to treat dye-contaminated water.

Keywords

• Waste management
• One-pot synthesis
• Rod-shape composite
• Cationic dye
• Adsorption process mechanism
• Wastewater treatment