氨基功能化非织造布对水中Cr(Ⅵ)的吸附性能研究

Adsorption properties of amino functionalized nonwovens for Cr(Ⅵ)in water

针对水中Cr(Ⅵ)高效去除难题,采用表面共沉积-后交联法,将含有大量氨基的聚乙烯亚胺引入聚丙烯无纺布表面,制备出一种新型的高效Cr(Ⅵ)吸附剂PP-E-PEI,并研究了其对水中Cr(Ⅵ)的吸附性能。结果表明,聚乙烯亚胺成功反应至聚丙烯纤维表面,且在酸性溶液中结构稳定;氨基质子化是吸附Cr(Ⅵ)的必要条件,pH≤3.0时才能有效吸附Cr(Ⅵ);共存阴离子的电荷量和浓度是影响Cr(Ⅵ)吸附选择性的主要因素,与Cl^(-)、NO_(3)^(-)等一价阴离子共存时吸附材料对Cr_(2)O_(7)^(2-)的选择性系数(K)可达400以上,与HPO_(4)^(2-)、SO_(4)^(2-)等二价阴离子共存时吸附材料对Cr_(2)O_(7)^(2-)的选择性系数(K)在7~54;采用聚丙烯无纺布作基材,吸附剂呈纤维膜形态,在吸附完成后易从溶液中分离。

Aiming at the problem of efficient removal of Cr(Ⅵ)in water,this paper adopted the method of surface co-deposition and post-crosslinking,introduced polyethylenimine containing a large number of amino groups onto the surface of polypropylene non-woven fabric,prepared a new kind of efficient Cr(Ⅵ)adsorbent PP-E-PEI,and studied its adsorption performance of Cr(Ⅵ)in water.The results showed that polyethylene-imine successfully reacted on the surface of polypropylene fiber,and the structure was stable in acidic solution.Amino protonation is a necessary condition for Cr(Ⅵ)adsorption.Only when pH≤3.0 can Cr(Ⅵ)be effectively adsorbed.The charge quantity and concentration of coexisting anions are the main factors affecting the adsorption selectivity of Cr(Ⅵ).When co-existing with the univalent anions such as Cl^(-)and NO_(3)^(-),the selectivity coefficient(K)of the adsorption material for Cr_(2)O_(7)^(2-)can reach more than 400.The selectivity coefficient(K)of the adsorbed material for Cr_(2)O_(7)^(2-)is between 7 and 54 when it coexists with the bivalent anions such as HPO_(4)^(2-)and SO_(4)^(2-).Using polypropylene non-woven fabric as the substrate,the adsorbent is in the form of fiber film,easy to be separated from the solution after the completion of adsorption.