以天然淀粉为原料,采用逐步分子修饰合成淀粉基重金属捕集材料,并对产品的铜镍离子捕集能力进行了评估分析。首先淀粉分子通过醚化作用,引入阳离子季铵型基团;在此基础上,继续磷酸化引入阴离子基团;合成过程添加尿素,促进各类基团的交联网状结构,淀粉分子的氨基甲酸酯化同时也引入非离子基团,最终获取了多种电荷分布的淀粉分子修饰产品。研究结果表明: 3-氯-2-羟丙基三甲基氯化铵(CHPTAC)用量为淀粉质量(mL/g)0.4,50℃下作用4h,阳离子化取代度最高为1.61%。三聚磷酸钠质量百分比浓度4%,pH值6~7,120℃下作用2h,负电荷磷酸化淀粉分子的取代度为0.026。低浓度的尿素能提高磷酸化淀粉的反应效率,质量百分比浓度高于3%时,会与淀粉分子氨基甲酸酯化作用增强结构的交联。不同基团取代度的产品对铜镍离子均具有捕集效果,阳离子化和阴离子磷酸酯化的取代度分别为1.42%和0.018,淀粉基捕集材料对30mg/L浓度含铜、镍离子溶液的重金属去除率高达98%。
In this paper, natural starch was used as raw material to synthesize
starch based heavy metal trapping materials by stepwise molecular modification,
and the trapping ability of copper and nickel ions
was evaluated. The starch molecules first introduce cationic quaternary
ammonium groups through etherification. On this basis, continue to introduce
the phosphorylation of anionic groups. The addition of urea in the synthesis
process could promote the cross-linked structure of various types of groups and
introduced non ionic groups. Finally, modified starchproducts with multiple
charge distribution were obtained. The results showed that the dosage of CHPTAC
was 4%(mL/g) of starch quality, reaction temperature was 50℃ for 4h, the degree of cation substitution was 1.61%.The mass
concentration of sodium tripolyphosphate was 4%, pH value as 6-7, reaction
temperature was 120℃ for 2h, the degree of substitution of negative charged could
reach0.026.Low concentration of
urea can improve the reaction efficiency of phosphorylated starch. When the
mass percentage concentration is higher than 3%, it can enhance the
cross-linking of starch with the molecular carbamate. The products with
different degree of substitution have a certain trapping effect on the copper
and nickel ions. When the cationic and anionic phosphate esterification degree
of substitution were 1.421% and 0.018, the removal rate of 30 mg/L copper and
nickel ions solution could reach 98%.