Preparation and characterization of clay-oyster shell composite adsorption material and its application in phosphorus removal from wastewater

• Published in: Sustainable chemistry and pharmacy 2023-05, Vol.32, p.101023, Article 101023
• Main Authors: Zhou, Zhijian, Xu, Qiulin, Wu, Zijun, Fang, Xitong, Zhong, Qiuling, Yang, Jinlan, Yan, Jie, Li, Qiaoguang
• Format: Article
• Language: English
• Subjects: absorption; adsorption; Clay; compression strength; death; equations; eutrophication; green chemistry; kaolin; Oyster shell powder; oyster shells; Phosphorous removal; phosphorus; porosity; Porous material; shrimp; sorption isotherms; surface area; thermodynamics; wastewater
• ISSN: 2352-5541; 2352-5541
• DOI: 10.1016/j.scp.2023.101023

Phosphorus wastewater is prone to eutrophication, causing anoxic death of fish and shrimp. Adsorption materials can be added to remove phosphorus from water. In the paper, three kinds of composite adsorption materials (KA-OS, FC-OS and BC-OS) were prepared by compounding, granulating and calcining kaolin, fireclay and ball clay with oyster shell powder respectively. The results showed that these materials were porous structures and possessed good mechanical properties, among which BC-OS was the best, the maximum bending stress was 123.075 N and the compressive strength was 2.612 Mpa. And its pore size and specific surface area was 25.11 nm and 24.555 m2/g respectively. The results of phosphorus removal showed that the maximum adsorption capacity of three kinds of materials was greater than 88 mg/g, and the phosphorus concentration after phosphorus removal was less than 1 mg/L. The kinetic behaviors of the composite adsorption materials were consistent with Pseudo-second-order equation (R2 ≥ 0.986). Intra-particle diffusion and outer film diffusion jointly controlled the rate. And the thermodynamic behaviors of BC-OS and KA-OS were consistent with the Freundlich isotherm model (R2 ≥ 0.963). SEM observed that a large number of spherical and flocculent products were formed after phosphorus absorption by the three materials. [Display omitted] •Utilization of oyster shell waste was reported.•Oyster shells/clay composite with good mechanical properties was prepared for phosphorus removal.•The phosphorus removal process of materials was demonstrated and described.