不同交联度PP-g-4VP离子交换纤维的制备及对水溶液中铬离子吸附的研究

Studies on the preparation of PP-g-4VP ion exchange fibers with different cross-linking degrees and their adsorption properties for chromium ion in aqueous solution

通过控制交联剂(DVB)及单体(4-VP)浓度等工艺,研制了不同交联度的聚丙烯接枝4乙烯基吡啶离子交换纤维(PP-g-4VP),旨在改善纤维的结构及其再生吸附和重复使用性能。实验结果表明,随着DVB含量增大,纤维的接枝率下降,交联度增加,而吸水率下降。所制的PP-g-4VP和PP-g-4VP-季铵盐纤维对Cr^(6+)静态吸附量大,分别达约6.5mmol/g和4mmol/g。交联度低时,纤维对Cr^(6+)吸附速度越快,穿透点前流出液浓度较低。纤维吸附Cr^(6+)后用1N NH_3·H_2O能完全洗脱,再生吸附性能良好。

The ion exchange fibers of polypropylene-graft-4-vinyl pyridine (PP-g-4VP) with different degrees of crosslinking were prepared by controlling the feed contents of crosslinking agent of divinylbenzene {DVB) and the amounts of monomer of 4-vinyl pyridine (4-VP) and so on, aiming at the modification of the structures and regenerated adsorption properties of the fibers.The experimental results indicated that with the increase of the feed contents of DVB,the grafting rate of the fibers decreased and their degrees of crosslinking increased accompanying with the decrease of water absorption.The resultant fibers of PP-g-4VP and PP-g-4VP-quaternized possess high static adsorption capacity for Cr6+ ,which reach about 6.5mmol/g and 4mmol/g,respectively.When the fibers were in low degrees of crosslinking, they possess a great adsorption speed and therefore can keep the effluent in low concentration before breakthrough point.The fibers adsorbed for Cr6+ to saturation can be regenerated by 1N NH3·H2O and the regenerated fibers still have excellent dynamic adsorption capacity for chromium ion.