【作者】 李海燕；

【导师】 汪东风；

【作者基本信息】 中国海洋大学 ， 食品科学， 2011， 博士

【摘要】 在水产养殖过程中,仅有20%的饵料转化为动物蛋白,其余的残余饵料和排泄物进入水体,使氮、磷等营养物质含量过高,导致水体的富营养化。水体的富营养化会引发藻类大量繁殖,消耗水中的溶解氧,导致鱼贝类大量死亡;其中有害藻类如赤潮异弯藻,产生的毒素会通过食物链对人体造成伤害,进而引发食品安全问题。本文针对水体中存在的主要问题氮磷过量、藻类过量繁殖等问题,以壳聚糖为材料,制备出一系列壳聚糖树脂,为治理养殖水体水质提供新途径。1)壳聚糖树脂的孔洞少、脆性大、粒径小等缺点限制了其工业化应用。PEG 2000可以较好地增加壳聚糖树脂的孔洞;通过IPN网络共混技术,将壳聚糖与聚乙烯醇共混,制备了壳聚糖-聚乙烯醇共混树脂(CPR),该树脂具有较好的机械性能。CPR的最优制备条件为:壳聚糖与聚乙烯醇共混比为5:2,戊二醛用量为10 ml/100ml,PEG 2000添加量为1.2%。FTIR分析表明,壳聚糖与聚乙烯醇之间形成了典型的IPN网络结构。壳聚糖与其它吸附剂共混可以制备粒径较大的树脂微球。以硅藻土为例,当壳聚糖、聚乙烯醇、硅藻土三者质量比为5:2:2时,40目以上树脂的质量比重达到88.82%,粒径明显增大。2)水体中的氮主要来源于蛋白质,为提高壳聚糖树脂对蛋白质的吸附能力,采用Mannich反应和活化偶联反应,制备了壳聚糖固化单宁树脂(TICR)和壳聚糖-Ce4+固化单宁树脂(TCCR),并优化了制备条件。研究了时间、BSA初始浓度、pH、温度对TICR和TCCR吸附BSA的影响。吸附初始阶段,随着时间的延长,吸附量迅速增加,300 min时达到吸附平衡;随着BSA初始浓度的增加,平衡吸附量不断增加,当树脂吸附位点达到饱和时,增加浓度对平衡吸附量影响不大;pH为6.0时,吸附量最高;温度升高有利于吸附的进行,但影响不明显。TICR对BSA的吸附等温线符合Langmuir吸附模型,为优惠吸附。吸附是熵推动的自发吸热过程,升温有利于吸附。吸附属于二级动力学吸附,TICR对BSA的吸附过程由粒子内扩散和液膜扩散联合控制,以粒子内扩散为主。3)用金属配位分子印迹法制备了壳聚糖-La(Ⅲ) -印迹磷树脂(CLPR),CLPR平均粒径为粒径300μm。树脂的吸附效果与磷溶液的初始浓度、吸附时间、pH吸附温度有关:随着初始浓度的增加,吸附量不断增加,当吸附达到饱和时,增加浓度对吸附量无显著影响;pH对吸附量影响较大,在酸性条件下,吸附容量大,碱性条件下,吸附量大大降低;温度升高有利于吸附的进行,但对吸附量的影响不明显;吸附初始阶段,随着时间的延长,吸附量迅速增加,60 min后吸附达到平衡。CLPR对磷的吸附等温线符合Langmuir吸和Frendlich附模型,为优惠吸附。吸附属于二级动力学吸附,CLPR对磷的吸附过程由表面扩散和颗粒内扩散联合控制。用KOH再生后,连续使用7次,CLPR仍具有很好的吸附性能4)制备了壳聚糖-稀土-皂土复合树脂颗粒(CRB),研究其对有害藻赤潮异弯藻细胞的作用机理。结果显示,在低浓度(0.1、0.3 g/L)时,藻细胞可溶性糖含量随处理时间的延长而不断增加。原因是当藻细胞受到损害时,为维持细胞的正常生理功能,细胞出现应急反应,可溶性糖作为细胞的内容物含量增加。高浓度(0.5、0.7、0.9g/L)时,细胞受损严重,自身机能得不到恢复,导致可溶性糖含量降低。蛋白质含量的变化与可溶糖相似。在同一浓度下,赤潮异弯藻细胞中MDA含量随着处理时间的延长而不断增加,相同处理时间时,CRB浓度越高,藻细胞中MDA含量也越高。MDA含量与电导率呈正相关。对藻细胞抗氧化系统的研究发现:在低浓度处理初期,藻细胞具有较强的自我保护能力,体内出现应急反应,SOD、POD和CAT三者均表现为增加,其中POD起到主要抵御作用;但随着浓度和作用时间的增加,细胞自身的防御系统不能抵抗外来的侵害,藻细胞受损,功能下降,相应的酶活也下降,直至细胞死亡。CRB对有益藻海水小球藻同样具有抑杀作用,当浓度为0.1 g/L时,连续培养5d后,细胞数量仅为初始细胞数的16%。更多还原

【Abstract】 In aquaculture, only 20% feed were used by aquaculture organisms. The residual feed and the excrement of aquaculture organisms remained in aquaculture water. So the aquaculture water is rich in nitrogen and phosphorus. The higher contents of nitrogen and phosphorus can cause water eutrophication and lead to the excessive growth of algae. Algae consume the dissolved oxygen in water, which can lead to the mass mortality of aquaculture organisms for hypoxia. Some toxic algae can secrete toxins which can transport through food chain to human body, and raise the food safety issues.Therefore, the objectives of this study are to treat the problems in aquaculture water, such as the higher contents of nitrogen and phosphorus, the excessive growth of algae. In this study, a series of chitosan resins are prepared to treat the aquaculture water.1) The shortcomings of chitosan resin, small pores, brittle and small particle size, limit its industrial applications. As pore-foaming agent, PEG 2000 can increase the amount of pores inside chitosan resin significantly. Chitosan-PVA blend resin （CPR）, is prepared by IPN blend method. CPR has high mechanical strength. The best preparation condition is that the ratio of chitosan and PVA is 5:2, the dosage of glutaraldehyde is 10 ml/100 ml, and the dosage of PEG 2000 is 1.2%. FTIR indicates that it form the typical IPN structure between chitosan and PVA. In addition, chitosan can form larger particle size through blending with other adsorbents. Take diatomite for example, when the ratio of chitosan, PVA and diatomite is 5:2:2, the particle size increased obviously, the particle size larger than 40 mash account for 88.82% of the total chitosan resin.2) The nitrogen in aquaculture water is mainly originated from protein. To improve the adsorption ability of chitosan resin for protein, chitosan immobilized tannins resin （TICR） and chitosan-Ce⁴⁺ immobilized tannins resin （TCCR） were prepared by Mannich reaction and activation coupling reaction, respectively. The influences of several parameters （time, BSA initial concentration, pH and temperature） on the adsorption of TICR and TCCR were investigated. The results show that the adsorption capabilities increase with the increasing of time, and the adsorption equilibrium were achieved after 300 min. And the adsorption capabilities increase with the increasing of BSA initial concentration until the adsorption saturation achieve. The higher temperature is advantageous to the adsorption.The adsorption process of TICR for BSA is an endothermic process, and basically follows the Langmuir equation. The adsorption kinetics is satisfied with second-order equation. The adsorption mass transfer process is influenced and controlled by the liquid film diffusion and intraparticle diffusion. The process is mainly controlled by the intraparticle diffusion.3) Chitosan-La（Ⅲ）- phosphate ions imprinted resin （CLPR） were prepared by ion-imprinted method. The average particle size of CLPR is 300μm. The influences of time, temperature, initial concentration and pH were investigated. The results show that the adsorption capabilities increase with the increasing of time, and the adsorption equilibrium were achieved after 60 min. And the adsorption capabilities increase with the increasing of BSA initial concentration until the adsorption saturation achieve. And the influence of temperature is not obviously.The adsorption process of CLPR for phosphate follows the Langmuir and Frendlich equation. The adsorption kinetics is satisfied with second-order equation. The adsorption mass transfer process is influenced and controlled by the liquid film diffusion and intraparticle diffusion. Using KOH as desorption agent, CLPR can repeat adsorption–desorption cycle seven times.4) Chitosan-Re-bentonite resin （CRB） was prepared to inhibit Heterosigma akashiwo. With the treatment of low concentration of CRB （0.1、0.3 g/L）, the amount of soluble carbohydrate increased with the increasing of treatment time. The reason is that when Heterosigma akashiwo cells are under stress, the cells show the emergency response to keep the normal cell physiological function. So the soluble carbohydrate contents increase. Under the high concentration of CRB stress, the cells are damaged. So the soluble carbohydrate contents decrease. The change trend of protein is similar to the soluble carbohydrate.With the same concentration of CRB, the MDA content of Heterosigma akashiwo cells increases with the increasing of treatment time. With the same treatment time, the MDA content increases with the increasing of CRB concentration. The effects of CRB on the antioxidant system of Heterosigma akashiwo cells are also investigated. The results show that in the initial stage SOD, POD and CAT activities are increased to protect cells, but with the increasing of treatment time and CRB concentration, the cells were damaged seriously, SOD, POD and CAT can not protect the cells.The effect of CRB on Chlorella Vulgaris is similar to Heterosigma akashiwo. With the treatment of 0.1 g/L CRB, the number of cells only remains 16%.更多还原