聚合物强化超滤处理重金属废水

【作者】 郜国英；

【导师】 邱运仁；

【作者基本信息】 中南大学 ， 化学工艺， 2011， 硕士

【摘要】 重金属废水毒性大,聚合物强化超滤通过对废水中重金属离子的浓缩与分离,以实现从低浓度废水对重金属的回收,既减轻了重金属对环境的污染又实现了变废为宝。本文选用丙烯酸-马来酸共聚物(PMA-100)为络合剂,采用聚合物强化超滤技术分别处理了含铬、铜、镍、镉离子的模拟废水。研究了聚合物/金属离子质量比(P/M)、溶液pH、盐浓度、运行时间等对重金属截留效果的影响。结果表明：溶液pH值、P/M、盐浓度对铬、铜、镍、镉离子截留率影响很大；在一定P/M条件下,适当提高溶液pH值有利于金属离子的截留；在一定pH条件下,金属离子的截留率随P/M的增加而增加；实现铬、铜、镍、镉单离子溶液有效截留的最佳溶液pH值分别为5.0、5.3、6.0、5.8,较佳P/M值为7、6、7、6；当外加盐浓度增大时,金属离子截留率逐渐降低；研究还表明小分子竞争络合剂的存在使铬、镍截留率下降。此外还考察了聚合物强化超滤选择性分离重金属的研究,对比研究了铜、镍混合金属离子溶液和单离子金属离子溶液的截留率。结果表明：聚合物/金属离子质量比和溶液pH值对选择性分离效果影响明显,在混合溶液P/M=3、pH=5.3时,铜、镍离子的选择性分离系数大于260；外加盐的存在可影响铜、镍金属离子与聚合物之间的相互作用,从而实现两者的分离。更多还原

【Abstract】 Wastewater contains heavy metals are harmful because of their higher toxicity. The process of complexation-ultrafiltration can recycle the heavy metals from wastewater of low concentration, through separating and concentrating the water. Hence it has a positive significance to reduce environmental pollution and can turn waste into treasure.Copolymer of acrylic acid and maleic acid (PAM-100) was used as complexing reagent for the treatment of wastewater containing Cr(Ⅲ), Cu(Ⅱ), Ni(Ⅱ), Cd(Ⅱ) by ultrafiltration respectively. Effects of mass ratio of polymer/metallic ions (P/M), pH, time, salt concentration on the retention of Cr(Ⅲ), Cu(Ⅱ), Ni(Ⅱ), Cd(Ⅱ) and permeate fluxes were investigated. Results indicate that the retentions of Cr(Ⅲ), Cu(Ⅱ), Ni(Ⅱ) and Cd(Ⅱ) depend strongly on P/M, pH and salt concentration. The retentions of metal ions increase with the increase of pH at a certain P/M, and increase with the increase of P/M value at a certain pH. The rejection of metal ions is greater at pH=5.0, P/M=7 for Cr(Ⅲ), P/M=6, pH=5.3 for Cu(Ⅱ), pH=6.0, P/M=7 for Ni(Ⅱ),and pH=5.8, P/M=6 for Cd(Ⅱ). The retention of metal ions is influenced by salt concentration, the retention decreases with the addition of NaCl and Na2SO4. In addition, the retention of metal ions decreases with the addition of competitive complexing reagent with small molecular weight.Furthermore, selective separation for Cu(Ⅱ), Ni(Ⅱ) are also studied, by the comparison of the two mixed metal ions solution with the single-ion solution retention. The results showed that:mass ratio of polymer/metallic ions (P/M), pH significant effect on selective separation. The copper, nickel ion selective separation coefficient S reached more than 260 at a mixed solution of P/M=3, pH=5.3. The presence of the addition of NaCl and Na2SO4 can affect the interaction between metal ions and the complexing reagent,thus achieving the separation between the two.更多还原