粒状交联聚丙烯酸钠的制备及其对Pb2+的吸附性能

Preparation of Granular Crosslinked Sodium Polyacrylate and its Pb^(2+) Adsorption Performance

采用反相悬浮聚合法制备了粒状交联聚丙烯酸钠(gc-PAANa)凝胶,对gc-PAANa凝胶样品进行了SEM、FT-IR和TGA表征及溶胀率测试。将gc-PAANa凝胶用于吸附水溶液中Pb^(2+)的研究,结果表明,在p H=3.0~5.0 gc-PAANa凝胶对Pb^(2+)的吸附具有非常好的效果。0.02~0.1 mol×L-1 Ca2+/Mg2+的存在对Pb^(2+)的吸附几乎无影响,Pb^(2+)初始浓度对吸附结果影响较大,gc-PAANa凝胶对初始浓度低于350 mg×L-1的Pb^(2+)废水,Pb^(2+)的去除率可达到95%以上。gc-PAANa凝胶对Pb^(2+)的吸附动力学符合准二级模型,吸附等温线符合Langmuir模型,293 K下的最大吸附量为446.98 mg×g-1;吸附热力学分析表明,gc-PAANa凝胶对Pb^(2+)的吸附属于自发的放热反应。XPS分析表明,gc-PAANa凝胶吸附Pb^(2+)的机理属于-COO-与Pb^(2+)的螯合作用。吸附-解吸附循环实验显示,gc-PAANa凝胶处理含Pb^(2+)废水具有很好的重复利用性能。

Granular crosslinked sodium polyacrylate (gc-PAANa) gel was prepared by reverse suspension polymerization and characterized by SEM, FT-IR and TGA, and its swelling ratio was also measured. Moreover,this gc-PAANa gel was used for Pb2+adsorption from aqueous solutions. The experimental results indicate that the gc-PAANa gel has excellent Pb2+ adsorption performance in the pH range of 3.0~5.0, and the presence of Ca2+ or Mg2+ (0.02~0.1 mol?L?1) has no obvious effect on the Pb2+ adsorption. More than 95% Pb2+ can beremoved from wastewater when the initial Pb2+ concentration is below 350 mg?L?1. The adsorption kinetics and isotherms of Pb2+ on gc-PAANa gel follow pseudo-second order model and Langmuir model, respectively. Themaximum Pb2+ adsorption capacity is 446.98 mg?g?1 at 293 K. The adsorption the rmodynamic analysis revealsthat Pb2+ adsorption on gc-PAANa gel is a spontaneous and exothermic process. Furthermore, adsorption mechanism analysis by XPS indicates that Pb2+ adsorption is mainly attributed to the chelation of -COO? with Pb2+. 5 cycles of adsorption-desorption results suggest that the gc-PAANa gel possesses good reusability for the treatment of Pb2+ wastewater.