粉末活性焦对水中磷酸盐的吸附性能

以蒙东褐煤为原料，通过沉降炉炭化活化一步法制备了粉末活性焦（COKE），其具有丰富的孔隙结构，以微孔为主，占据比表面积的79.3%.考察了活性焦对水中磷酸盐的吸附性能，并进一步研究了吸附时间、温度、初始pH值、初始磷酸盐浓度、活性焦投加量和共存离子对吸附过程的影响，以及吸附动力学、吸附等温线和热力学特征.结果表明：活性焦对水体中的磷酸盐具有良好的吸附性能.在30℃，pH=7的条件下，利用20.00g/L活性焦吸附1mg/L磷酸盐溶液，60min即可达到吸附平衡，此时吸附率可达89.4%.当吸附温度越高（10~40℃），活性焦投加量越大，溶液pH值在6~7时，活性焦对水中磷酸盐的去除效果越好.共存离子的存在（NO₃^-、SO₄^2-、CO₃^2-）对活性焦吸附磷酸盐有抑制作用.活性焦对磷酸盐溶液的吸附过程较好符合Freundlich模型（R²>0.99）和准二级动力学模型（R²>0.99），最大吸附容量为1.746mg/g（30℃），并通过热力学分析发现此过程为自发的吸热反应.利用傅立叶红外光谱分析进一步表明，活性焦吸附磷酸盐主要依靠配位交换.与活性炭相比，活性焦性价比更高，具有良好的应用前景.

The adsorption property of powder activated coke on phosphate in water

Powdered activated coke (COKE) derived from one-step carbonization and activation of Mengdong lignite was obtained by using a sedimentation furnace. It had developed pore structure on the surface, which is dominated by micropores, accounting for 79.3% of its specific surface area. The phosphate adsorption ability of the COKE was studied by investigating the effects of adsorption time, temperature, initial pH, initial phosphate concentration, the dosage of COKE and coexisting anions on the adsorption process. Furthermore, the adsorption kinetics, isotherms, and thermodynamics were analyzed, correspondingly. It was shown in the results that coke has good adsorption properties for phosphate in water. The adsorption equilibrium was reached at 60min when 1mg/L phosphate solution in neutral was adsorbed by 3.0g/L COKE at the temperature of 30℃, and the adsorption efficiencies are 89.4%. It was found that the optimum pH value for the adsorption was 6~7, and the extent of adsorption of phosphate by COKE in water increased significantly with increase in temperature and concentration of COKE. The presence of competing anions (NO₃^-, SO₄^2-, CO₃^2-) has an inhibitory effect on the adsorption of phosphate by COKE under the researched conditions. The adsorption process of phosphate on COKE could be successfully described by Freundlich model (R²>0.99) and quasi-secondary kinetic model (R²>0.99). The maximum adsorption capacity was 1.746mg/g at the temperature of 30℃. It was shown by thermodynamic analysis that the adsorption is spontaneous endothermic reaction with that the value of ΔH is 37.548kJ/mol. Further, the results of FTIR analysis showed that phosphate adsorption of COKE mainly depended on coordination exchange. Compared with activated carbon, the COKE prepared in this study has higher performance-price ratio, and hence, would be expected to show a favorable application prospect.