粘土矿物及无机絮凝剂对有害赤潮的治理研究

IOCAS-IR > 海洋环流与波动重点实验室

	粘土矿物及无机絮凝剂对有害赤潮的治理研究
	孙晓霞
学位类型	博士
	2001
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	海洋生物学
关键词	有害赤潮防治粘土矿物无机絮凝剂
摘要	在害赤潮作为一种全球性的海洋灾害，给海洋环境、水产养殖业和人类健康造成巨大危害，研究赤潮的发生规律，探索新的、经济有效的赤潮的防治方法具有重要的科学意义和应用前景。本文针对中国沿海常见赤潮生物种，研究了粘土矿物双赤潮生物基本生理指标的影响，进一步探讨了粘土矿物的控制赤潮机制；并针对粘土矿物去除效率不高的特点，制备出具有较高絮凝胶效率的改性粘土；此外，本文还首次将无机高分子絮凝效率的改性粘土；此外，本文还首次将无机高分子絮凝剂MMH（混合金属氢氧化物正电胶体）和PSMS（聚硅酸金属盐）用于赤潮治理研究中，并探索了上述赤潮防治剂的环境生态效应，主要成果与内容有：1、粘土矿物的筛选采集国内外近30种粘土矿物，分别考察了它们对中国沿海常见赤潮生物种赤潮异弯藻（Heterosigma akashiwo）和塔玛亚历山大藻（Alexandrium tamarense）的去除效果。结果表明，不同粘土矿物对赤潮生物的絮凝能力有显著差别，实验筛选出去除效果较好的几种粘土，分别为来自美国的Chemically treated kaolin、WHOI土、江苏吴县高岭土及苏州特号土等。通过絮凝实验得到上述几种粘土矿物对两种赤潮生物的絮凝曲线，发现不同粘土矿物对赤潮生物的最大去除率及达到最大去除率所需的粘土浓度有较大差别，同一粘土矿物对不同赤潮生物的去除效果也不相同。塔玛亚历山大藻较赤潮异变藻更易被粘土矿物去除。2、粘土矿物对赤潮生物的生理效应研究了高岭土对赤潮异弯藻和塔玛来历山大藻生长繁殖、叶绿素a含量、光合作用以及呼吸作用的影响。结果表明，高岭土对赤潮生物生长、叶绿素a含量及光合作用均有抑制作用，表现为随粘土浓度的增加及作用时间的延长，抑制作用增强，并认为这可能与粘土的加入导致光照效应降低及藻类生长的营养环境改变有关。实验同时发现高岭土对不同赤潮生物的抑制程度不同，塔玛亚历山大藻上述各项生理指标比赤潮异弯藻更易受粘土影响。3、无机絮凝剂的制备及絮凝作用研究主要考察了无机高分子絮凝剂MMH及PSMS（聚硅酸金属盐），包括聚硅酸氯化铝（PSAC）和聚硅酸硫酸铝（PSAS）的合成及对赤潮生物的絮凝作用。在MMH的合成过程中，考察了镁铝摩尔比及制备温度对MMH絮凝赤潮异弯藻的影响，认为镁铝摩尔比为2的条件下制备的MMH具有较好的絮凝和沉降性能，其絮凝赤潮异弯藻的最佳用量为1.5mmolAl/L。在PSAS的合成中采用三因子三水平的正交试验设计，得到PSAS的最佳制备条件为：SiO_2浓度 = 2%， Al~(3+)/SiO_2 = 1, pH = 4。絮凝实验结果表明，PSAS对赤潮生物的絮凝效果优于传统絮凝剂AS（硫酸铝），同时PSAS对不同赤潮生物的絮凝效果也不同，认为这主要与不同赤潮生物的形态结构、运动性及胞外分泌物有关。4、粘土矿物表面改性及机理研究为提高粘土矿物去除赤潮生物的效率，分别用插入法和表面吸附法制备改性粘土。实验得出插入法的最佳制备条件为：制备温度70 ℃，镁离子浓度2mol/L；表面吸附法中粘土和MMH（混合金属氢氧化物胶体）的适宜配比为：粘土/MMH=10。改性后粘土去除赤潮异弯藻的效率较改性前提高2-3倍。相关分析表明，改性粘土去除赤潮生物的效率与改性后表面电位呈正相关，两种情况下R~2均大于0.8，说明表面电位是影响粘土矿物去除赤潮生物的一个重要因素。5、赤潮治理的现场模拟实验及环境生态效应在1999年夏季胶州湾中肋骨条藻（Skeletonema costatum）赤潮的发生现场进行了改性粘土及PSAS对藻类去除率、悬浮物、DO、COD、pH等指标的影响研究。结果表明，改性粘土及PSAS对现场中肋骨条藻有较高的去除率，1g/L的改性高岭土和改性蒙脱土对中肋骨条藻的去除率分别可达77%和93%，1ml/L的PSAS去除率达90%以上。DO的含量轻微下降，不致影响其他生物的生长，COD下降幅度较大，达50-80%。6、赤潮防治剂对中国对虾的毒性研究进行了粘土、次氯酸钙、氯化铝和氯化铁对中国对虾的毒性试验，结果表明，1g/L的高岭土对虾基本无毒性；次氯酸钙在低浓度下对对虾无毒，在高浓度下对对虾有急性毒性效应，安全使用浓度为0.5ml/L游离氯；氯化铝和氯化铁在对虾体内有一定的积累，其长期的毒性效应有待于进一步的分析。上述几种试剂均可用于粘土矿物的改性处理中，是比较安全的赤潮防治剂。
其他摘要	As a kind of global oceanic disaster, Harmful Algal Blooms (HABs) have increased in frequency, intensity and geographic distribution, seriously threaten human health, marine environment and fishery resources, brought a great amount of economic loss on marine aquaculture. Studying new, economical and effective HAB mitigation methods has important scientific significance and application prospect. In this dissertation, we studied the effect of clay on the fundamental psychological index of China common HAB species, and put forward methods of clay surface modification in order to improve the removal efficiencies of clay mineral. In addition, the inorganic flocculants MMH and PSMS were used in HAB mitigation for the first time, and the environmental and ecological effect of above agents were investigated accordingly. The main results are as follows. 1. Study on screening of clay minerals About 30 kinds of clays were collected from home and abroad to investigate their removal efficiencies on HAB organisms Heterosigma akashiwo and Alexandrium tamarense. Experimental results showed that the coagulation efficiencies of HAB organisms varied with clay kind markedly, and the chemically treated kaolinite, the clays from wuxian, suzhou and WHOI showed higher coagulation capability. The coagulation curves of these clays on Heterosigma akashiwo and Alexandrium tamarense indicated that the maximum removal rates varied with clay kinds and HAB species. Compared with H. akashiwo, A. tamarense was easy to be removed. 2. Psychological effects of clay on HAB organisms The effects of kaolinite on the growth, chla content, photosynthesis and respiration of H. akashiwo and A. tamarense were studied. Results showed that kaolinite inhibited the growth, chla content and photosynthesis of HAB organisms, and the inhibition effect enhanced with time and clay concentration, which was considered as due to reduction on light and change on trophic environment of algae after adding clay. In addition, the inhibition of kaolinite varied with algal species, A. tamarense was more sensitive than H. akashiwo. 3. Study on preparation of inorganic flocculants and their coagulation on HAB organisms The preparation of inorganic flocculants MMH and PSMS (including PSAC and PSAS), and their coagulation on HAB organisms were studied in this part. In the process of MMH preparation, Mg/Al molar ratio and temperature were investigated. MMH prepared under the condition of Mg~(2+)/Al~(3+) = 2 had higher removal efficiencies and coagulation rates on Heterosigma akashiwo and 1.5 mmolAl~(3+)/L were obtained as the economic dosage used to coagulate Heterosigma akashiwo. 3-factor, 3-level orthogonal test were designed to prepare PSAS, and the optimum conditions were: concentration of SiO_2 = 2%, Al~(3+)/SiO_2 = 1 and pH = 4. Coagulation experiments showed that the removal efficiencies PSAS varied with HAB species due to different size, structure, locomotion and extracellular excrete of algal cells, and were much higher than that of traditional flocculant AS. 4. Studies of clay surface modification and coagulation mechanisms In order to improve the removal efficiencies of clays on HAB organisms, insertion reaction method and surface adsorption method were used to prepare modified clays. Preparation experiments showed that the optimum preparation conditions for the two methods were: preparation temperature = 70 ℃, and concentration of Mg~(2+) = 2mol/L for insertion reaction method and clay/MMH = 10 for surface adsorption method. The removal efficiencies of modified clays were 2-3 times higher than that of the original ones. Correlation analysis indicated that the removal efficiencies were positively correlated with the surface potential of clay particles, R~2 ＞ 0.8 in both cases, which indicated that surface potential was an important factor affected removal efficiencies. 5. Environmental and ecological effect of modified clays and PSAS During the HAB of Skeletonema costatum in Jiaozhou Bay in the summer of 1999, modified clays and PSAS were used to remove HAB organisms in the field. The items determined included removal efficiency of HAB organisms, suspended material, DO, COD and pH. Results showed that the removal efficiencies achieved 77% and 93% when 1g/L modified montmorillonite and modified kaolinite were added respectively and 90% when the concentration of PSAS was 1ml/L. The contents of DO were decreased slightly after treatment, which wouldn't affect the growth of other organisms. The contents of COD decreased markedly, achieved 50-80%. 6. Toxicity of anti-HAB agents on Penaeus Chinensis. The toxicity of clay, Ca(ClO)_2, AlCl_3 and FeCl_3 on Penaeus chinensis were studied in order to provide further material for HAB mitigation. Results showed that 1g/L clay had no toxic effect on shrimps; Ca(ClO)_2 showed no toxicity in low concentration, but had acute and chronic toxicity in high concentration and the safe dosage was 0.5mg/L free chlorine; AlCl_3 and FeCl_3 could be accumulated in the bodies of shrimps and the long term toxicity needed further investigation. The above agents were considered to be safe for clay modification.
页数	113
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/415
专题	海洋环流与波动重点实验室海洋生态与环境科学重点实验室
推荐引用方式 GB/T 7714	孙晓霞. 粘土矿物及无机絮凝剂对有害赤潮的治理研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,2001.

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