木质素磺酸钠接枝聚乙烯胺凝胶吸附铅(Ⅱ)离子

Adsorption of lead(Ⅱ)ion by sodium lignosulfonate-g-polyvinylamine gel

以造纸废料木质素磺酸钠(LS)和丙烯酰胺(AM)为原料,过硫酸钾(KPS)为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂,制备木质素磺酸钠接枝聚丙烯酰胺(LS-g-PAM)凝胶。而后通过Hofmann降解反应,酰胺基转变为氨基,制备木质素磺酸钠接枝聚乙烯胺(LS-g-PVAM)凝胶。用红外光谱表征LS-g-PVAM的结构。以LS-g-PVAM为吸附剂吸附水中的Pb^(2+),吸附量为125.56 mg·g^(-1)。研究了溶液pH和温度对于吸附量的影响。LS-g-PVAM对Pb^(2+)的吸附符合Langmuir吸附等温方程和准二级动力学方程,LS-g-PVAM对于Pb^(2+)的吸附为单层化学吸附。LS-g-PVAM吸附Pb^(2+)后可再生循环利用。

Sodium lignosulfonate-g-polyacrylamide(LS-g-PAM)gel was prepared using sodium lignosulfonate(LS)that was papermaking waste and acrylamide(AM)as starting materials,potassium persulfate(KPS)as initiator,N,N′-methylene diacrylamide as crosslinking agent.Sodium lignosulfonate-g-polyvinylamine(LS-g-PVAM)gel was prepared by Hofmann degradation reaction of LS-g-PAM,in which-CONH_(2) was transformed into-NH_(2).LS-g-PVAM was characterized by FT-IR.Pb^(2+)was adsorbed by LS-g-PVAM as adsorbent.The adsorption capacity of LS-g-PVAM for Pb^(2+)was 125.56 mg·g^(-1).The influence of pH and temperature on adsorption capability was examined.The adsorption process of LS-g-PVAM for Pb^(2+)matched with pseudo-second-order kinetic model,which indicated that the adsorption process for Pb^(2+)may be a rate-limiting step via chemical adsorption.The adsorption process also fitted with Langmuir isotherm adsorption equation,which suggested that the adsorption process is monolayer adsorption.LS-g-PVAM had good regeneration performance,and it could be reused.