【摘要】 利用合成的非晶态磷酸锡作为吸附剂,研究了多种因素(pH、吸附时间、初始浓度、温度、离子强度)对吸附剂吸附水溶液中Pb2+的影响。结果表明,非晶态磷酸锡对Pb2+的吸附量随着pH(3～6)以及吸附时间的增大而增加。用Freundlich、Langmuir模型对等温吸附数据进行处理,Langmuir方程拟合效果最好,20℃时饱和吸附量达到377.36 mg/g。Dubinin-Radushkevich(D-R)模型研究表明,吸附机理属于化学离子交换。反应机理为非晶态磷酸锡中的H+与溶液中的Pb2+发生了离子交换反应。吸附过程的热力学研究表明,非晶态磷酸锡对Pb2+的吸附是一个自发的,吸热的过程,升温有利于吸附。离子强度实验结果表明,高盐强度对非晶态磷酸锡吸附Pb2+有一定的不利影响,但幅度不大,可以用于去除养殖海水中的Pb2+。所吸附的Pb2+可以用HCl解吸,说明非晶态磷酸锡具有重复利用的潜能。更多还原

【Abstract】 Amorphous tin(IV) phosphate was used as an adsorbent to remove Pb(II) from aqueous solution.The extent of adsorption was investigated as a function of pH,contact time,adsorbate concentration,reaction tempera-ture,and ionic strength.Experimental results showed that the amount of adsorbed lead ions increased with the in-creases of solution pH in the examined range(3~6) and reaction time.The equilibrium data were analyzed using the Freundlich or Langmuir isotherm model depending on temperature.The results showed that the sorption process followed the Langmuir model well.The maximum sorption capacity amounted to 377.36 mg/g at 20℃.The free energy Es(kJ/mol) obtained from the D-R isotherm also indicated the sorption process was mediated by an ion-exchange mechanism between Pb2+ and H+.The negative ΔG0 values and the positive ΔH0 and ΔS0 at various temperatures confirmed the adsorption processes were spontaneous and endothermic.Ionic strength experiments showed that it was feasible for amorphous tin(IV) phosphate in removing Pb2+ from hyper-saline media,such as marine culture wastewater.Desorption experiment in the media of HCl solution indicated the adsorbent could be reused,which enhanced its feasibility in practical application.更多还原