磷钼酸铵负载聚丙烯无纺布吸附剂的辐射接枝法制备及其对Cs(Ⅰ)的吸附性能

Preparation of ammonium phosphomolybdate polypropylene nonwovens adsorbent by radiation grafting method and its adsorption performance for Cs(Ⅰ)

采用电子束引发预辐射接枝法,将甲基丙烯酸环氧丙酯(GMA)接枝到聚丙烯(PP)无纺布上,接枝同时将磷钼酸铵(AMP)物理包裹到接枝聚合链缝隙中,生成了负载有AMP的PP-g-GMA接枝物(PP-g-GMA@AMP),AMP负载率为5.72%,GMA接枝率为32.41%。研究发现:在pH=6时,PP-g-GMA@AMP对Cs(Ⅰ)的吸附效率达到最大为97.23%;吸附剂PP-g-GMA@AMP的吸附动力学行为符合准二级动力学方程,吸附过程符合Langmuir吸附等温模型,理论最大吸附容量为2.59 mg/g;PP-g-GMA@AMP具有良好的重复利用性,重复利用3次吸附容量仅降低9.91%;Na(Ⅰ)、Ca(Ⅰ)和Mg(Ⅱ)溶液中,吸附剂对Cs(Ⅰ)依旧具有很强的选择性吸附能力,吸附平衡时,Cs(Ⅰ)的分配系数达120.45,Na(Ⅰ)、Mg(Ⅱ)和Ca(Ⅱ)的分配系数仅为2.71、1.23和1.84。根据分配系数的差异,通过0.5 mol/L NH_(4)Cl溶液洗脱,实现了Cs(Ⅰ)和Na(Ⅰ)、Mg(Ⅱ)、Ca(Ⅱ)的动态柱色谱分离,并将Cs(Ⅰ)流出液体积浓缩至进料液的1/5。

Glycidyl methacrylate(GMA)was grafted onto polypropylene(PP)nonwovens by electron-beam induced pre-irradiation grafting,and ammonium phosphomolybdate(AMP)was physically loaded on the grafted polymer to prepare a composite material called PP-g-GMA@AMP.The loading rate of AMP was 5.72%,and the grafting rate of GMA was 32.41%.The maximum adsorption efficiency of Cs(Ⅰ)by PP-g-GMA@AMP was 97.23%at pH=6.The adsorption kinetic behavior was in accordance with pseudo-second-order kinetic equation.The experimental results showed that the adsorption process using PP-g-GMA@AMP conforms to Langmuir adsorption model and the theoretical maximum adsorption capacity was 2.59 mg/g.PP-g-GMA@AMP showed good reusability and the adsorption capacity was reduced by only 9.91%after three repeated uses.PP-g-GMA@AMP showed excellent selective adsorption ability for Cs(Ⅰ)in the presence of Na(Ⅰ),Mg(Ⅱ),and Ca(Ⅱ).The distribution coefficient of Cs(Ⅰ)on AMP was 120.45,while those of Na(Ⅰ),Mg(Ⅱ),and Ca(Ⅱ)were 2.71,1.23,and 1.84,respectively.According to the difference in partition coefficients,Cs(Ⅰ)was separated from Na(Ⅰ),Mg(Ⅱ),and Ca(Ⅱ)by dynamic column chromatography using a 0.5 mol/L NH_(4)Cl eluent solution,and the Cs(Ⅰ)effluent liquid was concentrated to one-fifth the volume of the injection solution.