核桃壳接枝聚合物的制备及其吸附性能

Preparation and Adsorption Capacity of Walnut Shell Grafted Polymer

摘要:

以核桃壳、2-溴异丁酰溴制备的核桃壳大分子引发剂，FeCl3•6H2O/PPh3、Vc为催化体系，采用电子活化再生原子转移自由基聚合（AGET ATRP）法制备了核桃壳接枝聚丙烯酰胺（核桃壳-g-PAM）、聚甲基丙烯酸甲酯（核桃壳-g-PMMA）两种复合材料。利用红外光谱、差热分析及扫描电镜对复合材料的结构和形貌进行表征；两种复合材料对水中Pb(II)、Cu(II)的吸附量均高于核桃壳的吸附量。293 K时，10 mg核桃壳-g-PAM、核桃壳-g-PMMA对pH=5、50 mg/L Pb(II)的吸附量分别为40.5、48.5 mg/g，该吸附机理符合拟二级动力学模型，等温吸附过程可用Langmuir方程较好地描述。核桃壳-g-PAM、核桃壳-g-PMMA再生4次对Pb(II)的最低解吸率为93.4%、93.1%，表明核桃壳复合材料具有较好的再生能力。

Abstract:

The walnut shell grafted polyacrylamide or poly(methyl methacrylate) were prepared using AGET ATRP by walnut shell macroinitiator and monomer (acrylamide or methyl methacrylate) in the catalytic system of FeCl3•6H2O/PPh3 and Vc. The structure and appearance of composite material was characterized by FTIR, TG and SEM. The adsorptive properties of walnut shell-g-polyacrylamide or poly(methyl methacrylate)for metal ions were evaluated. The adsorptive capacity of composite materials was higher than walnut shell for Pb(II) and Cu(II). The results indicated that the maximum adsorption capacity was 40.5, 48.5 mg/g at 293 K and pH 5. 0 when an initial concentration of Pb(II) was 50 mg/L. Kinetic and isotherm studies of Pb(II) revealed that adsorption data followed the pseudo-second-order kinetic model and the Langmuir isotherm. The minimum desorption rate of Pb (II) was 93.4% and 93.1% for 4 times of regeneration. It showed that the materials had better regeneration capacity.