【作者】 任月明；

【导师】 张密林；

【作者基本信息】 哈尔滨工程大学 ， 材料学， 2008， 博士

【摘要】 含铜废水来源广、毒性大,严重危害自然环境和人体健康,因此对其进行处理尤为必要。本文以Cu（Ⅱ）为印迹离子,壳聚糖为印迹母体材料,青霉属菌丝体为核心,纳米Fe₃O₄为磁组分,经环氧氯丙烷交联和三聚磷酸钠的固化制备了铜离子印迹磁性生物吸附材料（Cu（Ⅱ）-IMB）,并用于含铜废水的吸附处理。结果表明该新型吸附材料优点为:（1）成本低廉能够大量生产;（2）吸附材料表面保留的Cu（Ⅱ）印迹空穴使得对Cu（Ⅱ）的吸附容量大大提高;（3）具有磁性在外加磁场下能够迅速从吸附后的溶液中分离出来。对制备Cu（Ⅱ）-IMB的单因素影响吸附性能的实验进行了探讨,首次利用响应面法实验优化了制备工艺,最大限度的提高了吸附容量。结果表明,在合成过程中,环氧氯丙烷、纳米Fe₃O₄和印迹铜离子的量是影响吸附材料吸附性能的重要因素,三者间存在一定的交互作用,纳米Fe₃O₄、印迹铜离子的量对吸附性能影响是正面的,且最显著。最佳合成条件为:菌丝体2g,CS0.2g,30℃下均匀搅拌交联反应3.0h,6mL2.5%的三聚磷酸钠溶液固化8.0h,以CuSO₄中的铜离子为印迹模板。加入环氧氯丙烷2.99g,Fe₃O₄为0.505g,印迹铜离子质量为25.245mg。通过扫描电镜、能谱分析、等离子体光谱分析、红外光谱、X射线衍射仪、振动样品磁强计对Cu（Ⅱ）-IMB的物质结构进行鉴定。结果表明,Cu（Ⅱ）-IMB的形状不规则,表面疏松且有许多的空隙结构,有着丰富的利于对重金属离子吸附的基团。和纯菌丝体及非印迹磁性生物吸附材料（NIMB）相比,比表面积和孔容积大大提高。制备过程中Fe₃O₄被成功的包埋且晶型未改变,但分布不均匀。Cu（Ⅱ）-IMB仍然保持超顺磁性,其磁特性参数随Fe₃O₄的含量不同而变化。以Cr⁶⁺、Zn²⁺、Ni²⁺为对比离子,对Cu（Ⅱ）-IMB在水溶液中对Cu²⁺的吸附性能进行了研究,并与制备的其它三种生物吸附材料进行了比较,并对其磁沉降性能、机械强度等进行了测定。结果表明,pH是影响吸附容量的重要因素,其对Cu²⁺、Zn²⁺、Ni²⁺吸附的最佳pH值在5.0左右,对Cr⁶⁺的为4.0左右。Cu（Ⅱ）-IMB、NIMB、CMB和MB对水溶液中Cu²⁺、Zn²⁺、Ni²⁺和Cr⁶⁺的吸附符合二级吸附动力学,均为颗粒内扩散和膜扩散联合控制过程,符合Langmuir或Freundlich吸附等温式。Cu（Ⅱ）-IMB对Cu²⁺的吸附速率最快,达吸附平衡时间最短为6.0h,二级吸附速率常为4.432x10^-3（（g/mg）/min）,比NIMB对Cu²⁺的提高33%,颗粒内有效扩散系数最大,为0.97223（mg/g）/min^1/2,对Cu²⁺的吸附性能最强,并表现较高的吸附选择性,由Langrnuir吸附等温式求出的单层饱和吸附容量为68.02mg/g,对Zn²⁺、Ni²⁺、Cr⁶⁺没有吸附选择性,吸附性能比NIMB好。印迹技术对吸附性能的提高贡献最大。Cu（Ⅱ）-IMB对Cu²⁺吸附过程为吸热反应,容易自发进行,以物理吸附为主,为熵增加过程。在外加磁场下,具有良好的磁沉降性能,与非磁性吸附材料比较,沉降时间缩短93%,沉淀效率提高25%,合成过程使其机械强度、交联度和抗酸性有较大提高。研究了其在二元体系和多元体系下的吸附竞争效应。实验表明,共存离子导致Cu²⁺吸附容量下降。二元体系实验证明,离子对吸附Cu²⁺的干扰随初始浓度的增加而增大。以Cu（Ⅱ）-IMB和NIMB为吸附材料的溶液中,共存的离子的吸附竞争能力为:Zn²⁺>Ni²⁺>Cr⁶⁺。有竞争离子存在时,Cu（Ⅱ）-IMB对Cu²⁺仍具有较高的选择吸附性能,并符合Langmuir模型。在多元金属离子体系中,Cu（Ⅱ）-IMB的吸附能力仍大于NIMB,对Cu²⁺具有专一的吸附选择性。Zn²⁺和Ni²⁺对Cu²⁺的协同竞争作用大于Ni²⁺和Cr⁶⁺的。吸附机理分析表明,吸附的过程中-NH₂和-OH与金属离子结合形成共轭结构。吸附金属离子后Cu（Ⅱ）-IMB非晶结构和Fe₃O₄的晶型未被影响,仍然保持原来的磁性。吸附了金属离子的Cu（Ⅱ）-IMB用0.01M EDTA在25℃下,解吸20min,氢氧化钠再生1.0h后,能够重复使用5次以上。引入BP神经网络的理论与方法,创新性地建立了Cu（Ⅱ）-IMB吸附Cu²⁺体系的影响因素的预测与控制模型,达到了良好的预测效果。为吸附实验的定量研究开创出一条有效的途径。本模型的建立可在计算机上进行某些设计与运行参数的选取。同时,能够实现对运行效果的预测,为工艺运行的在线控制提供了途径。更多还原

【Abstract】 Copper-containing wastewater is abroad and harmful to human being health and natural environment, so it is necessary to treat it. In this paper, a Cu（Ⅱ） ion imprinted magnetic biosorbent （Cu（Ⅱ）-IMB） was synthesized by using Cu²⁺ as imprinted ion, chitosan （CS） as imprinted matrix, fungal mycelium as core, nano-Fe₃O₄ as magnetic component. It was crosslinked by epichlorhydrin （ECH） and fixed by tripolyphoshate sodium, using in copper-containing wastewater treatment. Results showed that the main advantages of this new adsorbent were: （1） it is low cost that can be synthesized in large quantity with waste fungal mycelium from industry. （2） The adsorption capacity is improved by imprinting technique for the target molecule due to molecular geometry. （3） The easy separation of magnetic biosorbent from treated solution can be achieved by a magnetic field.The influencing reaction conditions during preparation of Cu（Ⅱ）-IMB were firstly optimized by response surface method （RSM） in order to get its best adsorption capacity. Results showed that the key factors to affect the adsorption capacity were the dosage of ECH, nano-Fe₃O₄ and imprinted Cu²⁺during the prepared process, and they had alternating relations. The affections of nano-Fe₃O₄ and imprinted Cu²⁺ on adsorption were right and most marked. The optimum prepared conditions were: mycelium 2g,CS0.2g, mixing equably at 30℃for 3.0h, fixing by 6mL 2.5% tripolyphoshate sodium for 8.0h. Cu²⁺ of CuSO₄ as imprinted template. The adding dosages were 2.99g ECH, 0.505g Fe₃O₄ and 25.245mg imprinted Cu²⁺.SEM, EDX, ICP, FT-IR, XRD and VSM were used to study the structure identification. Results showed that the shape of Cu（Ⅱ）-IMB was irregular, the surface was loosen and had lots of interspaced structure. There were plenty of groups favorable for heavy metal adsorption. The specific area and the pore volume improved greatly compared with pure mycelium and non-imprinted magnetic biosorbent （NIMB）. Fe₃O₄ was embedding in the biosorbent successfully during preparation but the crystal was not changed, and disturbed asymmetrically.Cu（Ⅱ）-IMB kept supermagntic and magnetic character parameters were different with varied Fe₃O₄ dosages.Taking Cr⁶⁺、Zn²⁺、Ni²⁺ as comparing ions, the adsorption characters of Cu²⁺on Cu（Ⅱ）-IMB was studied and compared with the other prepared adsorbents. The mechanism strength, anti-acidity ability and magnetic settlement character were also measured. The results of adsorption character study showed that pH is the key factor that affects adsorption capacity. The optimum pH was 5.0 of Cu（Ⅱ）-IMB for Cu²⁺, Zn²⁺, Ni²⁺ adsorption and 4.0 for Cr⁶⁺ adsorption. The adsorption of Cu²⁺, Zn²⁺, Ni²⁺ and Cr⁶⁺on Cu（Ⅱ）-IMB, NIMB, CMB and MB in solution fit the second order kinetic model. The adsorption processes were controlled by both film and pore diffusion. The adsorption equilibrium data can be described in terms of the Langmuir or Freundlich isotherm. The adsorption speed of Cu²⁺ on the Cu（Ⅱ）-IMB was the fast and the adsorption equilibrium time was short for 6.0h. The adsorption speed of Cu²⁺ onto the Cu（Ⅱ）-IMB was the fast and was 33% higher than that of NIMB with K₂ was 4.432×10^-3（（g/mg）/min）.The diffuse coefficient was biggest of 0.97223 （mg/g）/min^1/2.Cu（Ⅱ）-IMB had strong adsorption capacity and high adsorption selectivity for Cu²⁺, single saturated adsorption capacity calculated from Langmuir equption was 68.02mg/g , but had no adsorption selectivity for Zn²⁺, Ni²⁺ and Cr⁶⁺, and its adsorption characters were better than that of NIMB.Thermodynamics study showed that the adsorption was endothermic reaction and spontaneous thermodynamically favorable. It was mainly governed by physisorption and the degrees of freedom increased during the adsorption. Cu（##）-IMB showed good magnetic settlement character under additional magnetic field. The settlement time shortened of 94% and settlement efficiency improved of 15% compared to non-magnetic adsorbent. The adsorption capacity, mechanism strength,joined degree and anti-acidity ability was high after the synthesis process. Adsorption competition affection was conducted in binary or multi-mixture solution system. The experiments showed that binary adsorption system experiments proved that disturbing ability for Cu²⁺ increased with the increasinginitial concentration of differentions. The order of compete adsorption capacity of heavy metals in solution on Cu（Ⅱ）-IMB and NIMB in turns was Zn²⁺>Ni²⁺> Cr⁶⁺.Cu（Ⅱ）-IMB still had high adsorption selectivity for Cu²⁺ and also fit Langmuir model although there were competing ions. In multi-ions solution, the adsorption capacity of Cu（Ⅱ）-IMB was higher than NIMB and had sole adsorption character. Cooperated competing effect on Cu²⁺of Zn²⁺ and Ni²⁺ was greater than that of Ni²⁺ and Cr²⁺. Adsorption mechanism analyses showed that -NH, -OH and heavy metals formed conjugated structure. Non-crystal structure of Cu（Ⅱ）-IMB and crystal model of Fe₃O₄ were not effected and it still kept the original magnetism. The desorption conditions was desorption by 0.1M EDTA for 20 minute and regenerated for 1.0h by NaOH. The results showed that Cu（Ⅱ）-IMB could be reused for more five times.A forecasting and controlling model of operational parameters was established innovatively based on BP nerve cell theory of Cu²⁺adsorption effect factors. Simulated results by the simulation model analysis were basically consistent with experimental value. This means to start an effective way for fixed quantify study of adsorption experiment. This indicated that some designs, choice of operational parameters, prediction of run effect could be finished on computer by the simulation model. This provided an effective way for on-line control in adsorption process.更多还原