废弃虾壳制备改性甲壳素凝胶球及其对金属离子的吸附性能

Preparation of Modified Chitin Gel Bead from Waste Shrimp Shell and Its Adsorption Properties for Metal Ions

以虾壳酶解残渣为原料,经5%盐酸脱钙处理4 h后,用45%氢氧化钠和460 W微波辅助脱乙酰处理10 min,得到脱乙酰度为40.4%的改性甲壳素。将改性甲壳素加入海藻酸钠水溶液中混合均匀,挤压滴入氯化钙水溶液中固化12h,制备得到直径为1.5~3.2 mm的凝胶小球,研究了该凝胶球对Pb^(2+)、Cr^(3+)、Ni^(2+)、Cu^(2+)、Co^(2+)和Zn^(2+)的吸附效果。结果表明:凝胶球对Cu^(2+)、Co^(2+)和Zn^(2+)的吸附效果最好,300 mg/L重金属离子溶液吸附处理8 h是较适宜的吸附条件,此条件下,Cu^(2+)、Co^(2+)和Zn^(2+)的吸附率分别达到94.2%、75.6%和57.3%。在Cu^(2+)-Co^(2+)-Zn^(2+)共存溶液体系中,凝胶球对3种离子的吸附率均有所提高,Cu^(2+)、Co^(2+)和Zn^(2+)的吸附率分别为95.1%、82.5%和67.5%。

Modified chitin with 40. 4 % deacetylation degree was obtained from enzymatic hydrolysis residue of shrimp shell,which was treated by 5 % HCl for 4 h and 45 % NaOH coupled with 460 W microwave for 10 min,and then prepared into gel beads with diameter of 1. 5- 3. 2 mm by adding sodium alginate,mixing evenly,and squeezing in calcium chloride solution for 12 h. The adsorption performances of the gel beads to metal ions（ Pb^2＋,Cr^3＋,Ni^2＋,Cu^2＋,Zn^2＋ and Co^2＋） were investigated. The adsorption rates of Cu^2＋,Co^2＋and Zn^2＋were found to be 94. 2 %,75. 6 % and 57. 3 % in 300 mg/L ion solutions by treating for8 h,and 95. 1 %,82. 5 %,67. 5 % in the Cu^2＋,Zn^2＋and Co^2＋coexisting system,respectively.