Document Type
Article
Publication Date
7-15-2016
Abstract
Mg/Al ratio plays a significant role for anion adsorption by Mg/Al-layered double hydroxides (Mg/Al-LDHs) modified biochar. In this study, Mg/Al-LDHs biochar with different Mg/Al ratios (2, 3, 4) were prepared by co-precipitation for phosphate removal from aqueous solution. Factors on phosphate adsorption including Mg/Al ratio, pH, and the presence of other inorganic anions were investigated through batch experiments. Increasing Mg/Al ratio in the Mg/Al-LDHs biochar composites generally enhanced phosphate adsorption with Langmuir adsorption maximum calculated at 81.83 mg phosphorous (P) per gram of 4:1 Mg/Al-LDHs biochar at pH 3.0. The adsorption process was best described by the pseudo-second-order kinetic model. Solution pH had greater effects on the phosphate adsorption by Mg/Al LDHs biochar composites with lower Mg/Al ratios. The presence of other inorganic anions decreased the phosphate adsorption efficiency in the order of F- > SO42- > NO2- >Cl-. Phosphate adsorption mechanism involves ion exchange, electrostatic attraction and surface inner-sphere complex formation. Overall, Mg/Al-LDHs biochar composites offer a potential alternative of carbon-based adsorbent for phosphate removal from aqueous solution.
Publication Source (Journal or Book title)
Science of the Total Environment
First Page
121
Last Page
129
Recommended Citation
Li, R., Wang, J., Zhou, B., Awasthi, M., Ali, A., Zhang, Z., Gaston, L., Lahori, A., & Mahar, A. (2016). Enhancing phosphate adsorption by Mg/Al layered double hydroxide functionalized biochar with different Mg/Al ratios. Science of the Total Environment, 559, 121-129. https://doi.org/10.1016/j.scitotenv.2016.03.151
