title: Enhancing phosphate adsorption by Mg/Al layered double hydroxide functionalized biochar with different Mg/Al ratios.
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 81.83mg phosphorous (P) per gram of 4:1Mg/Al-LDHs biochar at pH3.0. 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(-) > SO4(2-) > 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.
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China; School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Li
authors.affiliation: School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA. Electronic address: JJWang@agcenter.lsu.edu.
authors.forename: Jim J
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Baoyue
authors.initials: B
authors.lastname: Zhou
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China; Department of Biotechnology, Amicable Knowledge Solution University, Satna, India.
authors.forename: Mukesh Kumar
authors.initials: MK
authors.lastname: Awasthi
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China.
authors.forename: Amjad
authors.initials: A
authors.lastname: Ali
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China.
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Lewis A
authors.initials: LA
authors.lastname: Gaston
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China.
authors.forename: Altaf Hussain
authors.initials: AH
authors.lastname: Lahori
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China; Centre for Environmental Sciences, University of Sindh, Jamshoro, 76080, Pakistan.
authors.forename: Amanullah
authors.initials: A
authors.lastname: Mahar
keywords: Mg/Al ratio; Phosphate; adsorption; biochar; layered double hydroxides