一种提高粘土矿物去除赤潮生物能力的新方法

在研究粘土颗粒与赤潮生物絮凝作用的基础上，建立了粘土表面改性对其絮凝作用影响的理论模型，认为改变粘土颗粒的表面性质提高其去除赤潮生物能力的主要途径，提出在粘土中引入ＰＡＣＳ（聚羟基氯化铝）的改性方法。结果表明，对于微型原甲藻（Ｐｒｏｒｏ－ｃｅｎｔｒｕｍ ｍｉｎｉｍｕｎ）体系，粘土中引入微量ＰＡＣＳ后，其去除率达９０％以上的高岭土用量由原来的２ｇ／Ｌ降至０．１ｇ／Ｌ，去除效率提高近２０倍。考察了ＰＡ     

APPLICATION OF CLAYS TO REMOVAL OF RED TIDE ORGANISMS Ⅰ.COAGULATION OF RED TIDE ORGANISMS WITH CLAYS

Coagulation of red tide organism cells with clays is discussed in theory and the effects of some fac-tors on it are studied.A quantitative model is presented which describes how the coagulation varies withpH in solution.According to the model,within the pH-range between pH_(zpc_a)and pH_(zpc_b),V_R is negativeand the coagulation is strong and strongest at pH=(pH_(zpc_a)+pH_(zpc_b))/2.It is also demonstrated that whenthe diameter of clay particles is close to that of cells,the collision probability is low,resulting in weakercoagulation.The model results have been corroborated by experiments and so are scientific and theoreticalbases for application.     

APPLICATION OF CLAYS TO REMOVAL OF RED TIDE ORGANISMS Ⅱ.COAGULATION OF DIFFERENT SPECIES OF RED TIDE ORGANISMS WITH MONTMORILLONITE AND EFFECT OF CLAY PRETREATMENT

Study on the coagulation of four species of red tide organisms(Nitzschia pungens,Skeletonema costatum,Prorocentrum minimum and Noctiluca scintillans)with montmorillonite,and the effect ofmontmorillonite pretreatment on the coagulation shows that the capability for montmorillonite to coagu-late with them is in the order:N.pungens>S.costatum>P.minimum>N.scintillans.Thecoagulation is discussed from the aspects of the structure,shape,size,movement,habit,etc.of differ-ent species and the results are explained theoretically.The experimental results also indicate that the treat-ment of montmorillonite with acid can enhance its coagulating capability.This is due to the fact that Al(OH_2)_6~(+3),exchanged from the clay lattice by hydrogen ion H~+,forms hydroxy-aluminum polymers on thesurface of the montmorillonite.The hydroxy-aluminum polymers positively charge and increase the positivecharacteristic of the clay surface,and also serves as a bridge between adjacent surfaces of particles.Thesetwo functions enhance     

Mechanisms and factors affecting the adsorption of sodium alginate onto modified clays

Algal organic materials (AOMs) are one critical factor affecting the efficiency of modified clays used for the mitigation of harmful algal blooms (HABs). This study was conducted to develop a deeper understanding of the mechanisms and factors affecting the adsorption of AOMs onto modified clays. Sodium alginate (polysaccharide) and kaolinite modified with polyaluminium chloride (PACl) were used as AOMs and modified clay model substances, respectively, and the effects of modifier dosage, contact time, solution pH and ionic strength were investigated through batch adsorption experiments. Kinetics revealed that the alginate adsorption rate was described well by a pseudo-second order model. PACl effectively enhanced the adsorption capacity of kaolinite and increased the adsorption rate, and the optimum additive amount of PACl was 5%. The experimental data fitted both the Freundlich and Langmuir adsorption equations well. The adsorption thermodynamics for alginate onto modified clays suggests that alginate adsorption is a spontaneous process. The adsorption of alginate onto modified clays was highly dependent on pH, with a decrease in adsorption observed with increased pH to 9.48, but the opposite was true above pH 9.48. Finally, adsorption increased with increasing ionic strength.     

改性黏土法消除球形棕囊藻赤潮的现场实验与效果评估

球形棕囊藻是一种具有复杂异型生活史的有毒有害赤潮生物,近年来在我国近海频繁暴发成灾,形成的巨大囊体为国内外罕见。迄今还未见到有效消除囊体型球形棕囊藻赤潮的方法报道。本文通过海上围隔实验和现场赤潮消除工程跟踪监测,考察了喷洒改性黏土消除囊体型球形棕囊藻赤潮的可行性与效率,并分析了改性黏土法治理赤潮时对水体及沉积环境的可能影响。围隔实验结果表明,喷洒改性黏土可以有效消除水体中过量的微藻细胞,其中以少量多次喷洒方法的效果最好,生物量(chl a)去除率90%。在对2016年2月广西防城港附近海域球形棕囊藻赤潮消除时的跟踪监测结果表明,改性黏土法适用于工程化消除赤潮作业,能够快速消除水体中的大量球形棕囊藻囊体,随改性黏土絮凝体沉入海底的赤潮藻可以快速分解而失去活性。喷洒改性黏土对于赤潮水体的主要理化指标影响不显著,所监测的水体COD、pH和不同形态氮、磷、硅等生源要素浓度都在原有水质水平范围内波动。     

大型海藻龙须菜与锥状斯氏藻间的营养竞争研究

利用生物和化学方法研究了大型海藻龙须菜（Gracilaria lemaneiformis）与赤潮生物锥状斯氏藻（Scrippsiella trochoidea （Stein） Loeblich Ⅲ）共培养时二者的生长情况,以及二者之间营养盐NO-3、PO3-4竞争的情况.结果显示,两者共培养时,由于龙须菜的影响,锥状斯氏藻的生长周期以及所能达到的最大细胞密度与对照组相比都有所下降,且受抑制程度随龙须菜起始密度的增大而增强;而锥状斯氏藻对于龙须菜的生长不构成明显的影响.当龙须菜起始密度较低时（0.2、0.1gFW/L）,共培养组微藻细胞密度的下降是因为水体中NO-3的耗尽;当龙须菜起始密度较高时（0.5gFW/L）,共培养组微藻细胞密度的下降可能是因为龙须菜与微藻之间的“互荫效应”,或者龙须菜能够分泌出足够浓度的克生物质所致.龙须菜可作为有效吸收营养盐的大型海藻,用以降低近海水域富营养化程度及有害赤潮发生的几率.     

粘土-MMH体系对赤潮生物的絮凝作用机制研究

根据粘土表面改性对其絮凝作用影响的理论模型,提出在粘土中引入ＭＭＨ（混合金属层状氢氧化物正电胶体）的改性方法,考察了ＭＭＨ浓度及ｐＨ值对絮凝作用的影响。结果表明,粘土中引和ＭＭＨ后,显著提高了对赤潮异弯藻（Ｈｅｔｅｒｏｓｉｇｍａａｋａｓｈｉｖｏ）和新月菱形藻（Ｎｉｔｚｃｈｉａｃｌｏｓｔｅｒｉｕｍ）的去除效率,二者的适宜配比为ＭＭＨ;粘土＝０．１ｇ：１ｇ,在此基础上,进一步研究了ＭＭＨ促进粘土絮凝作     

春季长江口富营养化水域浮游植物群集对冲淡水和上升流的响应

A comprehensive study on the phytoplankton standing stocks, species composition and dominant species in the eutrophic Changjiang(Yangtze River) Estuary(CE) was conducted to reveal the response of phytoplankton assemblage to Changjiang Diluted Water(CDW) and upwelling in the spring. Phytoplankton presented peak standing stocks(13.03 μg/L of chlorophyll a, 984.5×103 cells/L of phytoplankton abundance) along the surface isohaline of 25. Sixty-six species in 41 genera of Bacillariophyta and 33 species in 19 genera of Pyrrophyta were identified, as well as 5 species in Chlorophyta and Chrysophyta. Karenia mikimotoi was the most dominant species, followed by Prorocentrum dentatum, Paralia sulcata, Pseudo-nitzschia delicatissima and Skeletonema costatum. A bloom of K. mikimotoi was observed in the stratified stations, where the water was characterized by low nitrate, low phosphate, low turbidity, and specific ranges of temperature(18–22 °C) and salinity(27–32). K.mikimotoi and P. dentatum accumulated densely in the upper layers along the isohaline of 25. S. costatum was distributed in the west of the isohaline of 20. Benthonic P. sulcata presented high abundance near the bottom,while spread upward at upwelling stations. CDW resulted in overt gradients of salinity, turbidity and nutritional condition, determining the spatial distribution of phytoplankton species. The restricted upwelling resulted in the upward transport of P. sulcata and exclusion of S. costatum, K. mikimotoi and P. dentatum. The results suggested that CDW and upwelling were of importance in regulating the structure and distribution of phytoplankton assemblage in the CE and the East China Sea.     

长江口及其邻近海域表层沉积物粒径及生源要素分布特征

针对2015年长江口及其邻近海域所采集的43个表层沉积物样品,通过粒径分析以及生物硅(BSi)、总有机碳(TOC)和总氮(TN)等生源要素参数的测定,系统探讨了长江口表层沉积物粒径及生源要素的时空分布特征以及各要素的相互关系。结果表明:(1)长江口及其邻近海域表层沉积物组成以黏土质粉砂、粉砂质砂和砂为主。研究区域内,粒径组成呈现明显的"南细、北粗,近岸细、离岸粗"的分布特征,长江口及浙江近岸泥质区的表层沉积物粒度最细,中值粒径(Φ)在5以上;(2)调查海域表层沉积物中BSi含量在0.22%~1.82%之间,沉积物中粉砂、黏土含量及平均粒径(Φ)均与BSi含量呈显著正相关(P0.01),黏土矿物和粉砂较多的细颗粒沉积物更易累计和保存BSi;(3)TOC和TN的含量分别在0.04%~1.17%和0.01%~0.26%之间,其分布特征与沉积物中值粒径(Φ)和BSi的分布也有明显的正相关性,说明细颗粒沉积物更有利于有机质保存,表层沉积物中的硅藻可能是有机物的来源之一。     

粘土矿物去除赤潮生物的动力学研究

于１９９２年４－９月进行粘土矿的絮凝赤潮生物（微型原甲藻）的动力学研究；考察粘土种类、浓度、第二组分（ＰＡＣＳ）和ＰＨ等因素对絮凝速率的影响，建立粘土矿物絮凝赤潮生物的动力学模型，从理论上分析和讨论各种因素的影响，并提出提高絮凝速率的方法和途径。结果表明，高岭土体系絮凝速率大于蒙脱土体系，其速率方程可用双分子反应来描述。其中，速率常数随絮凝过程发生变化；粒子间的相互作用能和作用半径是控制和影响絮凝