New insights into ball milling effects on MgAl-LDHs exfoliation on biochar support: A case study for cadmium adsorption

• Published in: Journal of hazardous materials Vol. 416; p. 126258
• Main Authors: Cui, Shihao, Zhang, Ran, Peng, Yutao, Gao, Xing, Li, Zhe, Fan, Beibei, Guan, Chung-Yu, Beiyuan, Jingzi, Zhou, Yaoyu, Liu, Juan, Chen, Qing, Sheng, Jie, Guo, Lili
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2021
• Subjects: Ball milling; Cadmium; Engineered biochar; Layered double hydroxides; Wastewater treatment; Ball milling; Cadmium; Engineered biochar; Wastewater treatment; Layered double hydroxides
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.126258

Ball milling (BM) as a solvent-free technology has been widely used to tailor the biochar-based adsorbents with high porosity and well dispersion for enhancing their environmental applications. In this study, the ball-milled layered double hydroxides (LDHs) biochar composite (B-LDHs-BC) was successfully fabricated with BM method for Cd(II) adsorption and the BM effects on the LDHs-BC structure-performance relationships were investigated. The solid-state characterization demonstrated the LDHs were successfully exfoliated by BM on the B-LDHs-BC surface which was identified by the enlarged basal spacing and reduced crystallite size of the LDHs. Although the BET surface area of B-LDHs-BC (226 m2/g) was slightly lower than the ball-milled BC, the B-LDHs-BC had more O-containing functional groups and higher adsorption capacity (119 mg/g). The kinetics experiments indicated that the Cd(II) removal by B-LDHs-BC was through both the physical and chemical adsorption processes, and the liquid membrane diffusion was the rate-controlling step. The positive BM effects mainly induced more abundant acidic functional groups and active adsorption sites, and thus enhanced Cd(II) performance of B-LDHs-BC. This work demonstrated a facile solvent-free method for production of the exfoliated LDHs modified BC composite, and also well illustrated the BM effects which can extend their practical use in environment. [Display omitted] •The LDHs were exfoliated on biochar support by ball milling method.•Ball milled LDHs biochar composite (B-LDHs-BC) was fabricated for effective Cd(II) adsorption.•New insights into ball milling effects between the LDHs and BC were fully provided.•Mechanisms of the Cd(II) adsorption on the B-LDHs-BC were comprehensively analyzed.