【作者】 陈文宾；

【导师】 王丽萍；

【作者基本信息】 中国矿业大学 ， 环境工程， 2010， 博士

【摘要】 重金属、有毒有机物排放入海后,被海洋生物吸收并随食物链积累与放大,严重损害海产品的质量,威胁生态环境与人类健康。因此,开展室内养殖海水主要污染重金属、有机物的有效净化技术研究,对于提高养殖海水环境质量和保证水产养殖业可持续健康发展具有重要意义。本文针对室内养殖海水污染特点和海水高复杂体系对重金属测定的化学干扰问题,研究和建立了测定重金属离子新方法;从海水中筛选出耐重金属离子的细菌,借助现代分子生物学技术对微生物进行研究;用海藻酸钠和四氧化三钴固定化,进行室内养殖海水中重金属吸附和有机物去除研究。借助XPS、XRD、FTIR、SEM等手段研究了海水中重金属离子去除机理。主要研究结论如下:1.合成了新型三氮烯类显色剂,建立了光度法测定海水中重金属离子铅（II）、锌（II）、汞（II）和镍（II）的新方法。这些方法具有分析简便、快速、准确度高特点,同时避免了国标测定方法中有毒试剂使用。2.从海水中筛选出对重金属有较好耐受性细菌。通过生理生化检测、显微镜镜检方法,并借助现代分子生物学技术对微生物进行鉴定,确定筛选的微生物为鞘氨醇单胞菌Sphingomonas sp. XJ2。经过多次诱导驯化后,菌体对Pb²⁺的最大去除率可以提高到95 %,吸附效果优于文献报道中绝大多数菌种。试验中发现菌体对其它重金属如Hg²⁺、Zn²⁺、Ni²⁺和COD也有较高去除率,对海水中污染物净化表现出良好效果。3.以海藻酸钠作为包埋剂,同时添加硅藻土对鞘氨醇单胞菌进行固定化,制备固定化小球化学稳定性好,溶胀性及破裂率低,减少微生物流失,使用周期可达30天以上。固定化小球对海水中Pb²⁺饱和吸附量达到163.9 mg/g,且受海水中共存盐类影响较小。吸附Pb²⁺后,可以用EDTA解吸,解吸五次后对Pb²⁺解吸率仍可保持90%,可以重复使用降低成本。固定化小球在不同温度条件下表现出对Pb²⁺、Hg²⁺、Zn²⁺、Ni²⁺等重金属离子良好吸附性能,可对不同季节养殖海水进行净化,重金属含量可达到海水水质II类标准。4.固定化小球吸附Pb²⁺动力学过程由液膜扩散与孔内扩散共同控制,满足准二级动力学模型条件,其等温吸附过程符合Langmuir模型。红外光谱及XPS研究表明,Pb²⁺主要是与C-H、C-O发生络合反应。XPS及XRD分析发现Pb²⁺与氧结合形成PbO无机微沉积晶体,这表明Pb²⁺在吸附剂上吸附主要是离子交换和无机微沉积过程。5.海藻酸钠固定化菌体具有生物吸附和生化降解两重功能。COD最佳去除条件为37℃,pH值7.0,搅拌强度120 r/min,振荡90 min,COD去除率达到86%,去除效果明显优于单独使用菌种的效果。净化后出水水质达到海水质量Ⅱ类标准。6.利用合成新型Co3O4纳米带材料吸附性能、再生性能好优点,去除养殖海水中重金属离子,其重金属吸附能力顺序为Hg²⁺ >Ni²⁺ >Pb²⁺ >Zn²⁺。处理后水质达海水水质II类标准。Co3O4负载鞘氨醇单胞菌制备复合吸附剂进行海水中重金属离子动态吸附试验,当流速为1.2 L/h,时间为100～120min左右,重金属离子去除率达到90%以上,处理后水质达海水质量I类标准;连续出水COD值均低于3.2 mg/L, COD去除率达85%。毒理学研究表明,纳米Co3O4粒子在吸附重金属过程中可能携带Pb²⁺进入细胞,使Pb²⁺在细胞膜或者细胞质中释放蓄积,联合导致对菌体的毒性。更多还原

【Abstract】 With the development of industry and agriculture alongshore, a large volume of waste water was discharged into the ocean, resulting serious pollution to the near shore seawater. It is very likely for the harzdous substances to accumulate in the food chain, which will induce the serious impairment of aquatic product and human health.Aiming to the aquaculture seawater pollution, bacterium resistant to heavy metals was screened and immobilized with sodium polymannuronate and nano Co3O4, obtaining complex sorbents. These sorbents were used for the removal of heavy metals and organic matter in the indoor aquaculture seawater. The adsorption mechanism for the removal of heavy metal, lead, was investigated through the media of XPS, XRD, FTIR and SEM. The results show that:1. Novel chromogenic agents were synthesized, a new determination methods for Pb（II）, Ni（II）, Zn（II）, and Hg（II） in the media of seawater were established. These methods had the merit of convenience, rapid, good accuracy and no use of deleterious chemical regent in the national standard method.2. The bacterium was identified as Sphingomonas sp. XJ2 by means of microscopic examination, physiological, biochemical detection, and modern molecular biology technology. After acclimatization for several times, this bacterium has good performance in removing heavy metals and organic matter from seawater.3. The bacterium was embedded with sodium polymannuronat and diatomite, the resulting ball had good mechanical strength、chemical stability and reduce the loss in the immobilized microorganisms process . The saturated extent of adsorption amounted to 163.9 mg/g at the temperature of 37℃with a little of adverse effect of coexisted salts.Batch adsorption studies showed that the ball also has good performance for the removal of Hg²⁺, Zn²⁺, and Ni²⁺ from seawater. The seawater quality after the treatment met the II level of Sea water quality standard （GB 3097-1997）.The Pb²⁺ fixed by the immobilized ball can be desorbed with EDTA. The removal ratio amounted to 90% after recycled for 5 times, which indicated the feasibility of reutilization.4. The adsorption process of Pb（II） was controlled by liquid membrane diffusion and intrapore diffusion and conformed to pseudo-second dynamic model. The isothermal adsorption process agreed to Langmuir model. The adsorption was an endothermic reaction and spontaneous in nature.FTIR and XPS study indicated that Pb（II） was complexed by C-H and C-O bonds. XPS and XRD analysis showed inorganic micro crystal, PbO was precipitated, sugguesting an chemical mechanism.5. The optimal condition for the degradation of COD with the bacterium immobilized with sodium polymannuronat in the medium of seawater was pH 7.0 at 37℃oscillated at 120 rpm for 90 min with the dosage of 1.0 g/L.The degradation ratio for the COD with the bacterium immobilized with sodium polymannuronat reached 86%. The effluent quality met the second level of Sea water quality standard （GB 3097-1997）, which was suitable for aquaculture.6. Novel nano material, Co3O4, was synthesized take the advantages that with adsorbing capacity and good regenerate capacity of belt that used for removing heavy metals from seawater. The effluent quality met the II level of Sea water quality standard （GB 3097-1997）. The sequence of adsorption capacity was Hg²⁺ >Ni²⁺>Pb²⁺>Zn²⁺. The continuous-flow experiments were conducted with the bacterium immobilized with Co3O4 for the removal of Ni²⁺, Pb²⁺, Zn²⁺, and Hg²⁺ from aquaculture seawater.The removal ratio arrived to 90% at the flow rate of 1.2 L/h for 100-120 min. The water quality met I level. The COD value after treatment was less than 3.2 mg/L, equivalent to the removal ratio of 85%.FTIR study showed that ion exchange was conducted between Pb（II） and hydroxyl radical, resulting Pb-O bond. Toxicology studies showed that the nano particle may act as cockhorse in bringing the Pb²⁺ into the cell and then release and accumulate in the cell membrane or cytoplasm, resulting to the toxicity to the cell.更多还原