Phosphate adsorption using calcium aluminate decahydrate to achieve low phosphate concentrations: Batch and fixed-bed column studies

• Published in: Journal of environmental chemical engineering Vol. 11; no. 2; p. 109377
• Main Authors: Cheng, Peng, Liu, Yu, Yang, Lei, Ren, Qinting, Wang, Xue, Chi, Yanbin, Yuan, Honglin, Wang, Shaobin, Ren, Yong-Xiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2023
• Subjects: Adsorption; Calcium aluminate; Ligand exchange; Phosphorus; Secondary effluent; Ligand exchange; Phosphorus; Calcium aluminate; Adsorption; Secondary effluent
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2023.109377

In the wastewater treatment, achieving low phosphate concentrations is important to meet the increasingly stringent discharge requirements and alleviate eutrophication. Calcium aluminate decahydrate (CAH10) was prepared by a facile hydration method as a novel phosphate adsorbent. CAH10 exhibited a maximum adsorption capacity of 89.58 mg P/g at 25 °C in batch experiments. The phosphate adsorption followed the Elovich kinetic model and Freundlich isotherm model. The adsorption capacity at the equilibrium concentration of 0.1 mg P/L reached 3.27 mg P/g. High adsorption selectivity was obtained in the presence of common anions and humic acid. The phosphate adsorption mechanism mainly involved inner-sphere complexation and surface precipitation, which were supported by the SEM-EDS, FTIR and XPS results. The fixed-bed column adsorption performance demonstrated that CAH10 could effectively remove phosphate from real secondary effluent and achieve a low concentration of 0.1 mg P/L. The study indicated that CAH10 is a suitable adsorbent to remove phosphate in the context of secondary effluent polishing in wastewater treatment plants. [Display omitted] •P adsorbent was prepared by a facile hydration method using industrial material.•Adsorption capacity reached 3.27 mg P/g at a low P concentration of 0.1 mg P/L.•Phosphate was adsorbed mainly through ligand exchange and surface precipitation.•High removal performance was observed in fixed-bed test at a low EBCT of 1.18 min.•A low concentration of 0.1 mg P/L was achieved in real wastewater treatment.