Phosphate adsorption ability of biochar/Mg–Al assembled nanocomposites prepared by aluminum-electrode based electro-assisted modification method with MgCl2 as electrolyte

Abstract

In this work, the textural properties and phosphate adsorption capability of modified-biochar containing Mg–Al assembled nanocomposites prepared by an effective electro-assisted modification method with MgCl2 as an electrolyte have been determined. Structure and chemical analyses of the modified-biochar showed that nano-sized stonelike or flowerlike Mg–Al assembled composites, MgO, spinel MgAl2O4, AlOOH, and Al2O3, were densely grown and uniformly dispersed on the biochar surface. The adsorption isotherm and kinetics data suggested that the biochar/Mg–Al assembled nanocomposites have an energetically heterogeneous surface and that phosphate adsorption could be controlled by multiple processes. The maximum phosphate adsorption capacity was as high as 887mgg−1, as fitted by the Langmuir–Freundlich model, and is the highest value ever reported. It was concluded that this novel electro-assisted modification is a very attractive method and the biochar/Mg–Al assembled nanocomposites provide an excellent adsorbent that can effectively remove phosphate from aqueous solutions.