保水剂在不同铵盐溶液体系中的吸水和吸附铵离子特征

Water and ammoniumadsorption characteristics of water retaining agent in different solutions of ammonium salt

为探明保水剂与NH4+的相互作用,选用聚丙烯酸盐型保水剂(PAA)和聚丙烯酰胺型保水剂(P(AA-AM)),研究了保水剂在系列NH4Cl、NH4Cl-KCl、NH4Cl-CaCl2溶液体系中的吸水行为和对铵离子的吸附特征。结果表明:铵离子能显著降低保水剂的吸水倍率,并随铵离子浓度的增加,吸水倍率显著降低,相对吸水倍率与NH4+浓度之间具有显著的幂函数的减函数关系;NH4+、K+、Ca2+单一体系,NH4+-K+、NH4+-Ca2+共存体系对保水剂吸水倍率的影响按NH4+-K+<NH4+、K+<NH4+-Ca2+<Ca2+次序依次增强;虽然NH4+能显著降低保水剂的吸水倍率,但保水剂在吸水的同时也能大量吸附溶解于水中的NH4+,并随NH4+浓度的增加而增加,其吸附规律可用Freundlich吸附模型和线性吸附模型来表征;在不同溶液体系中,NH4+浓度相同时,保水剂对NH4+的吸附量差别很大,NH4+-K+或NH4+-Ca2+共存体系有利于NH4+吸附。NH4+单一体系、NH4+-K+、NH4+-Ca2+共存体系中,保水剂对NH4+的吸附量按NH4+<NH4+-Ca2+<NH4+-K+次序依次增大;P(AA-AM)的耐铵盐性和对NH4+的吸附能力均优于PAA。

In order to investigate the interaction between water retaining agents（WRAs）and NH4 ＋,polyacrylate（PAA） and poly acrylate-co-acrylamide（P（AA-AM））were selected as the tested WRAs to study the characteristics of water and NH4 ＋ adsorption in a series of solutions of NH4 ＋ Cl,NH4 ＋ Cl-KCl and NH4 ＋ Cl-CaCl2 respectively.The results showed that NH4 ＋ could obviously reduce the water absorbency of the WARs.The water absorbency was markedly decreased with the NH4 ＋ concentration increase.The relationship between relative water absorbency and NH4 ＋ concentration could be described by the minus power function.For NH4 ＋,K ＋,Ca 2＋ individual solution and NH4 ＋-K ＋,NH4 ＋-Ca 2＋ coexistent solution,the influence of WRAs on water absorbency followed the order NH4 ＋-K ＋ NH4 ＋、 K ＋ NH4 ＋-Ca 2＋ Ca 2.In despite of the sharply decrease of water absorbency with the rising of NH4 ＋ concentration,WRAs could largely adsorb NH4 ＋ and water.The adsorption capacity of NH4 ＋ increased with rising of NH4 ＋ concentration.This adsorption could be well described by Freundlich and linear model.In different solutions with the same NH4 ＋ concentration,the adsorption capacities of NH4 ＋ were different.NH4 ＋-K ＋ and NH4 ＋-Ca 2＋coexistent solutions were helpful to NH4 ＋ adsorption.In NH4 ＋,K ＋,Ca 2＋ individual solution and NH4 ＋-K ＋,NH4 ＋-Ca 2＋ coexistent solutions,the adsorption capacity of NH4 ＋ followed the trend of NH4 ＋ NH4 ＋-Ca 2＋ NH4 ＋-K ＋.Comparatively,P（AA-AM）was more tolerant to NH4 ＋ andhad stronger adsorption capability for NH4 ＋than P（AA）.