中文摘要：

采用镧（La）和阳离子表面活性剂十六烷基三甲基氯化铵（HDTMA-Cl）对活性炭进行联合改性,并考察了La和HDTMA联合改性活性炭（La-HDTMA改性活性炭）对水中磷酸盐和硝酸盐的吸附性能.实验结果表明,La-HDTMA改性活性炭对磷酸盐和硝酸盐具备一定的吸附去除能力.La-HDTMA改性活性炭对水中磷酸盐和硝酸盐的吸附动力学过程符合准二级动力学模型,吸附平衡数据可以采用Langmuir、Freundlich和Dubinin-Radushkevich（D-R）等温吸附模型加以描述.根据Langmuir等温吸附模型计算得到的La-HDTMA改性活性炭对磷酸盐和硝酸盐最大吸附量分别为4.15 mg·g^-1和11.2 mg·g^-1.当p H值由4增加到8时,La-HDTMA改性活性炭对水中磷酸盐的吸附能力增加;当p H值超过8时,对磷酸盐的吸附能力则下降.LaHDTMA改性活性炭对水中硝酸盐的吸附能力随p H值的增加而下降.水中共存的Cl^-、HCO3^-和SO4^2-等阴离子会抑制La-HDTMA改性活性炭对磷酸盐和硝酸盐的吸附.水中共存的硝酸盐会抑制La-HDTMA改性活性炭对磷酸盐的吸附,共存的磷酸盐亦会抑制La-HDTMA改性活性炭对硝酸盐的吸附.采用1 mol·L^-1Na OH溶液可以使71%吸附剂上的磷酸盐解吸下来,采用1 mol·L^-1的Na Cl溶液可以使97%吸附剂上的硝酸盐解吸下来.La-HDTMA改性活性炭对水中磷酸盐的吸附机制主要是阴离子交换、静电吸引、配位体交换作用和路易斯酸碱反应,对硝酸盐的吸附机制主要是阴离子交换和静电吸引作用.

英文摘要：

The adsorption of phosphate and nitrate from aqueous solution on activated carbon modified by lanthanum and cationic surfactant hexadecyltrimethylammonium chloride （ La-HDTMA-AC） was investigated in batch mode. Results showed that the La-HDTMA-AC exhibited high adsorption capacity for phosphate and nitrate in aqueous solution. The kinetic studies showed the adsorption of phosphate and nitrate fitted well with a pseudo-second-order kinetic model. The equilibrium adsorption date could be described by the Langmuir, Freundlich and Dubinin-Radushkevich （ D-R） isotherm models. According to the Langmuir isotherm, the predicted maximum phosphate and nitrate adsorption capacities on La-HDTMA-AC were 4.15 mg·g^-1 and 11.2 mg·g^-1 respectively. The phosphate adsorption capacity increased with pH from 3 to 8, but decreased with increasing pH from 8 to 12. The nitrate adsorption capacity decreased with pH from 3 to 12. The presence of coexisting anions such as Cl^-、HCO3^- and SO4^2- had a negative effect on phosphate and nitrate adsorption onto La-HDTMA-AC. The presence of coexisting phosphate in solution inhibited the adsorption of nitrate on La-HDTMA-AC, and the presence of coexisting nitrate in solution inhibited the adsorption of phosphate. The desorption experiments showed that 71% phosphate and 97% nitrate desorbed in 1 mol·L^-1 NaOH solution and 1 mol·L^-1 NaCl solution, respectively. The mechanisms for the adsorption of phosphate were anion exchange, electrostatic attraction, ligand exchange and Lewis acid-base interaction. The mechanisms for the adsorption of nitrate were anion exchange and electrostatic attraction.