Production of low-cost adsorbent with small particle size from calcium carbonate rich residue carbonatation cake and their high performance phosphate adsorption applications

Highlights

• An adsorbent was produced from carbonatisation cake, which is a waste product.

• The production procedure is a one-step process involving no chemicals.

• It is of higher quality and lower-cost than its chemical substitutes.

• Reactive calcium carbonate, has a small particle size and is a partially basic substance.

• Adsorption of phosphate onto calcined carbonatisation cake is pH dependent.

Abstract

This study investigated phosphorus removal from aqueous solutions using carbonatisation cake, which is a sugar residue containing a significant amount of reactive calcium carbonate. The chemical composition of the carbonatisation cake was determined, and the organic contamination of the carbonatisation cake and calcine in contact with water was determined. In addition, TGA, DTA, XRD, SEM-EDX, BET, FTIR, density, pHzpc and particle size distribution were analyzed for carbonatisation cake, product and post-phosphate removal calcined product. Batch experiments were performed to determine the effect of dose, phosphorus concentration, temperature and contact time on phosphorus removal from aqueous medium. Maximum phosphate adsorption capacity was found to be 65.16 mg g⁻¹ at 25 °C, pH of 6 and adsorbent dosage of 1 g L⁻¹ for a contact time of 180 min. Adsorption experiments were applied to adsorption isotherms. Kinetic, thermodynamic and mass transfer calculations were calculated. The results show that calcines produced by heating the carbonated cake to 600 °C, which is not cost-effective in sugar production, can be used effectively to remove phosphate from wastewaters.