碱活化载镁橘皮生物炭去除水体中的磷研究

Removal of Phosphate inWater by Alkali Activated Magnesium-loaded Orange Peel Biochar

以废弃的橘皮为原料,依次通过KOH、MgCl_(2)改性,然后在高温限氧的条件下制备了载镁橘皮生物炭(KMg-OPBC),对其进行了表征,考察了该材料对水体中磷的吸附去除能力。结果表明,镁以MgO、MgCl_(2)、Mg(OH)2的形态负载到KMg-OPBC上,通过沉淀络合和静电吸附作用实现了对磷的去除。当溶液初始pH为3.16~7.04时,更有利于磷的吸附,磷酸盐去除率均能达到90%以上;水体中共存离子CO_(3)^(2-)、HCO_(3)^(-)在高含量的情况下对KMg-OPBC除磷有抑制作用;KMg-OPBC对磷的吸附过程较好地符合Langmuir和Sips等温吸附模型及准2级动力模型,属于化学吸附过程,Sips理论最大吸附量为226.3 mg/g(25℃);KMg-OPBC除磷反应属于放热反应,升温不利于反应进行。在实际污水处理中,KMg-OPBC对磷酸盐也表现出了良好的选择吸附性能。

Waste orange peel was modified by KOH and MgCl_(2)to prepare KMg-OPBC under the condition of high temperature and oxygen limitation,and it was characterized and its ability to adsorb and remove phosphorus in water was investigated.The results showed that,magnesium was mainly loaded onto the KMg-OPBC in the form of MgO,MgCl_(2)and Mg(OH)2,and the removal of phosphorus was achieved through precipitation,complexation and electrostatic adsorption.When the initial pH of the solution was 3.16~7.04,it was more conducive to the adsorption of phosphorus,the removal rate of phosphate in water by KMg-OPBC could reach more than 90%.When CO_(3)^(2-)and HCO_(3)^(-)coexisted ions in water were at high content,it had an inhibitory effect on the phosphorus removal of KMg-OPBC.The adsorption process of phosphorus by KMg-OPBC fitted well with the Langmuir and Sips isotherm adsorption model and pseudo-second-order kinetic model,indicating that the adsorption was a chemical process.The theoretical maximum adsorption capacity of Sips was 226.3 mg/g(25℃).The phosphate removal by KMg-OPBC was an exothermic reaction,so temperature rise was not conducive to the reaction.In the actual sewage treatment,KMg-OPBC exhibited efficient and selective adsorption performance for phosphate.