有机改性粘土去除赤潮生物的机制研究

研究了季铵化合物改性粘土的制备条件对其去除赤潮藻效果的影响,探讨了该粘土体系高效除藻的机制.实验表明,十六烷基三甲基铵(HDTMA)可以有效地提高粘土的絮凝能力,同时HDTMA改性粘土中含有亚稳态HDTMA,增加了该改性粘土对赤潮生物的灭杀能力.改性粘土去除赤潮藻的能力与所吸附季铵化合物的杀藻能力、吸附量正相关,当老化时间延长、吸附季铵化合物稳定性增强时改性粘土除藻能力大大降低.结构不同的粘土对于吸附HDTMA的稳定化产生的空间阻力不同,在吸附量相同的情况下3层结构的蒙脱土中会有更多的亚稳态HDTMA产生;由于同离子效应,反应介质中高价金属阳离子的存在提高了亚稳态HDTMA的量,因此相应的改性粘土具有更高的赤潮藻去除能力.在60℃条件下吸附的HDTMA会更有效地占据粘土中的阳离子交换位,达到稳定态;而升高或降低温度都会有利于亚稳态HDTMA的出现,相应的改性粘土具有更高的赤潮藻去除能力.

Mechanisms of Removing Red Tide Organisms by Organo-Clays

We tested the influence of the preparation conditions of the quaternary ammonium compounds(QACs) modified clays on their capacities to remove red tide organisms,then discussed the mechanisms of the organo-clays removing red tide organisms.Hexadecyltrimethylammonium(HDTMA) improved the capacity of clays to flocculate red tide algae,and the HDTMA in metastable state enhanced the toxicity of the clay complexes to algae.The capacities of the organoclays correlated with the toxicity and the adsorbed amount of the QACs used in clays modification,but as the incubation time was prolonged the stability of the organo-clays was improved and the algal removal efficiencies of the clay complexes decreased.When the adsorbed HDTMA was arranged in different clays in which the spatial resistance was different,there was more HDTMA in metastable state in the three-layer montmorillonite.Because of the homo-ion effect the bivalent or trivalent metal ions induced more HDTMA in metastable state and the corresponding organo-clays had high capacities to remove red tide organisms.When the reaction temperature was 60°C the adsorbed HDTMA was easily arranged on cation exchange sites,if the temperature rose or fell the metastable HDTMA would increase so that the capacity of the clays was improved.