Abstract
Biochar is an excellent adsorbent for organic pollutants, but the removal effect for inorganic phosphorus is not satisfactory. In order to improve its phosphorus removal effect, ZnAl-LDH modified plane trees' bark biochar was presented in this paper. The plane trees' bark biochar was prepared by chemical-activation method by utilizing K(2)CO(3) as the activation agent. And then, ZnAl-LDH modified biochar was prepared by in-situ co-precipitation method with ammonia as the precipitate agent. As the sample was as little as 10 mg, the adsorption ratio was about 93% for the 25 mL of 20 mg/L PO(4)(3-). The saturated adsorption capacity for PO(4)(3-) was 103.1 mg/g, calculated by Langmuir equation, revealing the adsorption was mainly mono-molecular layer adsorption. The possible adsorption mechanism of phosphate mainly contained interlayer anion exchange, surface complexion and ligand exchange. Moreover, the absorbed sample were soaked in 5.5% Na(2)CO(3) solution for phosphate desorption, nearly 60% of the absorbed phosphate could be recovered and may reuse in the future.