【摘要】 以农林废弃物水稻秸秆作为生物炭原料，在400、550℃的热解温度下制备生物炭，探究CaCl₂、MgCl₂改性生物炭（CBC-400、CBC-550、MBC-400、MBC-550）对磷的吸附性能。研究结果显示，MBC和CBC对磷的吸附特点不同：MBC对磷的吸附速率慢但吸附量大，而CBC的吸附速率快但吸附量小。等温吸附实验结果显示，MBC-400和MBC-550的饱和吸附量分别为67.08、60.17 mg/g，高于CBC-400和CBC-550（5.97、18.51 mg/g）。根据吸附动力学结果可知，CBC的吸附过程符合准一级吸附动力学，MBC对磷的吸附分为表面扩散和吸附两个阶段进行。在初始pH为3～11范围内，由于CaHPO₄和Ca（H₂PO₄）₂的表面沉淀作用受pH的影响，CBC吸磷量随pH的升高而略微上升，而MBC在静电吸附作用下吸磷量随着pH的升高而下降。采用XPS、SEM、BET、FTIR、XRD对生物炭的吸附作用进行分析，结果表明CBC吸附磷主要是依靠表面吸附以及CaO颗粒与磷之间的表面沉淀作用来实现，而MBC主要依靠MgO与磷酸盐之间的化学反应。更多还原

【Abstract】 The biochar was prepared by using rice straw as raw material at the pyrolysis temperatures of 400 and 550 ℃. The adsorption performance of CaCl₂ and MgCl₂ modified biochar（CBC-400, CBC-550, MBC-400, MBC-550） on phosphorus was investigated. The results showed that the phosphorus adsorption characteristics of MBC and CBC were different. MBC had a slower adsorption rate but higher adsorption amount, while CBC had a faster adsorption rate but lower adsorption amount. The results of isothermal adsorption showed that the saturated adsorption amounts of MBC-400 and MBC-550 were 67.08 mg/g and 60.17 mg/g, respectively, which were higher than those of CBC-400 and CBC-550（5.97 mg/g and 18.51 mg/g）. According to the adsorption kinetic results, the adsorption process of CBC was consistent with quasi-first-order adsorption kinetics, and the adsorption of phosphorus by MBC proceeds in two stages: surface diffusion and adsorption. In the initial pH range of 3-11, the phosphorus adsorption by CBC increased slightly with the increase of pH due to the surface precipitation of CaHPO₄ and Ca（H₂PO₄）₂ affected by pH, while the phosphorus adsorption by MBC decreased with the increase of pH under electrostatic adsorption. The adsorption of biochar was analyzed by XPS, SEM, BET, FTIR and XRD, and the results showed that the phosphorus adsorption by CBC mainly relied on surface adsorption and surface precipitation between CaO particles and phosphorus, while MBC mainly relied on the chemical reaction between MgO and phosphate.更多还原