不同有机改性黏土对海洋卡盾藻去除作用的研究

On the effects of different organic modified clays on removing Chattonella marina

为筛选用于赤潮应急治理的高效、低毒除藻剂,研究了不同链长的季鳞盐改性黏土以及相同链长不同取代基团的季铵(鳞)盐改性黏土对海洋卡盾藻的去除作用,同时以斑马鱼和蒙古裸腹溞为对象,评价了筛选的改性黏土的毒性。结果表明,链长为十四烷基的改性黏土的除藻效果最好,其次为十二烷基和十烷基,而十六烷基较差;季铵(鳞)盐取代基团对改性黏土除藻效果的影响不大。十四烷基三丁基溴化磷改性黏土和双十四烷基二甲基乙基溴化铵改性黏土的除藻效果最好,对海洋卡盾藻的120 h半抑制质量浓度分别为6.11 mg/L和6.13 mg/L。毒性试验表明,这2种改性黏土对斑马鱼的毒性均较低,质量浓度为10～100 mg/L时,96 h后斑马鱼的存活率均为100%。改性黏土对蒙古裸腹溞有一定毒性,其中十四烷基三丁基溴化磷改性黏土24 h的LC_(50)远超过100 mg/L,双十四烷基二甲基乙基溴化铵改性黏上的LC_(50)为9.37 mg/L。因此,十四烷基三丁基溴化磷改性黏土的毒性更低,可作为赤潮治理的潜在除藻剂。

The paper is to report our research findings on the effects of different organic modified clays on removing Chattonella marina. As a matter of fact, the clays modified by tetradecyl quaternary ammonia may have different substituent groups, such as trimethyl, dimethyl phenmethyl and dimethyl ethide. However, all of them have similar removing efficiencies, though the substituent groups may suggest weaker effect on the quaternary ammonia in their algaecide activities of the modified clays. On the contrary, among the modified clays assayed, the clays with tetradecyl tributyl phosphonium bromide and ditetradecyl dimethyl ethide ammonium bromide prove to have the highest removing efficiency. In addition, the LC50 of 120 h of the two modified clays against C. marina was 6.11 mg/L and 6.13 mg/L, respectively, indicating that the two modified clays could remove the algae under low mass concentrations. Low toxicities of these two modified clays were shown in the acute toxicity tests of B. rerio. None of B. rerio were killed in 96 h after being exposed to the two modified clays at the mass concentration of 10 - 100 mg/L, though some differences in toxicity to M. mongolica could be exited between them. Therefore, it is obvious that the clay modified by tetradecyl tributyl phosphonium bromide tends to be less toxic to M. mongolica than that of modified by ditetradecyl dimethyl ethide ammonium bromide. Combining the high removal efficiency on C. marina and low toxicity to B. rerio and M. mongolica, it would probably be reasonable to believe that the clay modified by tetradecyl tributyl phosphonium bromide should be better a favorable choice to control harmful algal blooms （HABs） for its high efficiency but low toxicity to the fishery. However, further studies are awaited to prove the hypothesis we have proposed in the future in an open aqua-ecosystem.