为了阐明黏土方法治理有害赤潮的生态环境效应,研究了有机改性黏土对海水中营养盐和溶解氧、化学耗氧量、pH等主要水质因子的影响。结果表明,有机改性黏土对营养盐,尤其是磷酸盐有一定的吸附作用,吸附量随水体中磷酸盐浓度的增加而增大,不同有机改性黏土对海水中磷酸盐的吸附能力为:有机改性黏土Ⅰ〉有机改性黏土Ⅱ〉有机改性黏土Ⅲ。通过有机改性黏土对磷酸盐的吸附再释放作用研究,进一步探讨了磷酸盐释放作用对赤潮异弯藻(Heterosigma akashiwo)、东海原甲藻(Prorocentrum donghaiense)等赤潮生物生长的影响。实验结果表明,经过有机改性的黏土有利于提高其对磷酸盐的吸附能力,降低对磷酸盐的解吸率,缓解海水富营养化程度,虽然少量被吸附的磷酸盐能缓慢释放,但仍不足以维持赤潮生物的正常生长。同时利用有机改性黏土治理赤潮能显著改善溶解氧、pH、化学耗氧量等水质指标,有利于治理赤潮后的环境修复。
Three organic cationic surfactants——C12AGQAC, HDTMA and TPQAC——acted as coagu lant aids of organic modified clays Ⅰ , Ⅱ, and Ⅲ , which proved high efficiency of removal algae to mitigate harmful algae bloom. The object of this study under controlled laboratory conditions is to evaluate the organic modified clays impact on water quality, which is helpful for ensuring the security of coagulation/flocculation processes for HAB bloom control in stiu. The result showed that phosphate adsorption amount increased along with phosphorus concentration increasing, phosphate adsorption ability of different clays was modified clay Ⅰ〉 modified clay Ⅱ〉 modified clay Ⅲ 〉 unmodified clay, however, those were no obvious removal ability of nitrate. Simulating the phosphate absorption-desorption and the consequent effect on the growth of Heterosigma akashiwo and Prorocentrum donghaiense, the result revealed little phosphate desorption in seawater could not afford phytoplankton growth, so the clay flocculation would not bring a significant influence on promoting next algae bloom. Moreover,in the mitigation of algae bloom by modified clay flocculation methods, water quality parameters, such as Dissolved Oxygen (DO), Chemical Oxygen Demand(COD), and pH were controlled or smoothed compared with control. On all accounts, modified clays are helpful for promoting the environmental quality.