Preparation of layered double hydroxides using boron mud and red mud industrial wastes and adsorption mechanism to phosphate

Phosphate removal was important for wastewater treatment, and adsorption was an efficient treatment process. In this study, the layered double hydroxide adsorbent (BR-LDH), which was prepared under alkali conditions using industrial residues boron mud and red mud, was used to adsorb the phosphate. The prepared BR-LDH was characterised by X-ray diffraction, Scanning electron microscopy, Energy-dispersive X-ray spectroscopy, and Thermo-gravimetric-differential thermal analysis. Adsorption experiments were carried out as a function of dosage, contact time, temperature and initial pH of phosphate solution. The removal ratio of phosphate onto OBR-LDH reached 93%. The adsorption data showed a good compliance with the pseudo-second-order kinetic model. In addition, the mineral composition, the functional groups, the valence of elements and zeta potentials of OBR-LDH before and after adsorption were used to analyse the adsorption mechanism. The result of real wastewater suggested that OBR-LDH was excellent adsorbent for phosphorus removal from actual wastewater.