羧基碳复合材料的制备及其在重金属废水处理中的应用研究

发布时间：2018-06-14 17:09

本文选题：重金属废水 + 碳基复合材料　；参考：《江苏大学》2017年硕士论文

【摘要】：近年来,由于工农业的飞速发展,所伴随的环境污染问题日益严重,其中重金属污染问题尤为突出,如何有效解决重金属污染问题,一直是研究人员的研究重点。碳基复合材料由于其优异的理化特性,非常适合应用在重金属废水的处理过程中。本文制备了三种富含羧基的碳基复合材料:片状Fe_3O_4/羧基碳复合材料、TiO_2/羧基碳复合材料、Fe_3O_4/羧基碳复合材料,并将三种碳基复合材料分别应用于含铬废水中Cr(Ⅵ)的光催化还原以及含铜废水中铜离子的吸附。此外,以钢厂酸洗含铁废水和电镀含镍废水为原料制备了基于NiFe_2O_4的重金属污泥,将该重金属污泥作为电极材料组装成水系对称电池并进行了电池性能的研究。主要研究内容如下:(1)以FeSO_4·7H_2O、葡萄糖和EDTA为原料,通过低温碳化法一步合成了富含羧酸铁配合物的片状Fe_3O_4/羧基碳复合材料。片状Fe_3O_4/羧基碳复合材料以片状无定形碳作为载体,Fe_3O_4纳米颗粒均匀地分散在碳片中,并与EDTA中羧基配位形成羧酸铁配合物(Fe~Ⅱ(R-COO_)n~(2-n)和 Fe~Ⅲ(R-COO)_n~(3-n))。片状Fe_3O_4/羧基碳复合材料中存在大量的羧酸铁配合物,使得该材料具有优异的可见光吸收能。可见光照射下,Fe~Ⅱ(R-COO)_n~(2-n)和Fe~Ⅲ(R-COO)_n~(3-n)之间的Fe(Ⅱ)/Fe(Ⅲ)光催化循环,使得片状Fe_3O_4/羧基碳复合材料具有优异的可见光光催化还原Cr(Ⅵ)能力。此外,反应完成后,片状Fe_3O_4/羧基碳复合材料可通过磁性分离。(2)以钛酸四丁酯、葡萄糖和EDTA为原料,通过低温碳化法合成了TiO_2/羧基碳复合材料。通过Raman,SEM,EDS和TEM的表征,证实了TiO_2/羧基碳复合材料为纳米TiO_2颗粒均匀地分散在片状无定形碳中的结构。通过FT-IR和XPS谱图证明了TiO_2/羧基碳复合材料中含有大量羧基,并与TiO_2颗粒形成了TiO_2/EDTA配合物。TiO_2/羧基碳复合材料具有优异的可见光吸收性能和光催化还原Cr(Ⅵ)能力。可见光下,TiO_2/EDTA配合物通过配体到金属的电荷转移过程(ligand-to-metal charge transfer,LMCT)实现对Cr(Ⅵ)的光催化还原。(3)以FeSO_4·7H_2O和葡萄糖酸钠作为原料,通过一步低温碳化法合成Fe_3O_4/羧基碳复合材料。葡萄糖酸钠中的羧基与Fe(Ⅱ)配位形成羧酸铁配合物。在低温碳化过程中,部分羧酸铁配合物热分解为Fe_3O_4,大量的羧基仍保留在无定形碳中。Fe_3O_4/羧基碳复合材料富含的羧基有利于对水中Cu(Ⅱ)的吸附。Fe_3O_4/羧基碳复合材料具有优异的Cu(Ⅱ)吸附性能,其最大吸附容量为66.67 mg/g。以Fe_3O_4/羧基碳复合材料为吸附剂,进行了吸附动力学与热力学的研究。在各种动力学和等温线模型中,准二级动力学模型和Langmuir模型更符合Fe_3O_4/羧基碳复合材料对Cu(Ⅱ)的吸附过程。吸附结束后,Fe_3O_4/羧基碳复合材料可通过磁性分离。Fe_3O_4/羧基碳复合材料具有优异的稳定性,在酸性溶液中脱附后,可循环使用。(4)以钢厂酸洗含铁废水和电镀含镍废水为原料,经中和沉淀以及水热反应,获得基于NiFe_2O_4的重金属污泥。将基于NiFe_2O_4的重金属污泥作为电极材料,构建NiFe_2O_4//NiFe_2O_4水系对称电池。经电化学性能测试分析,Ni Fe2O4//NiFe_2O_4水系对称电池在放电电流密度为0.5 A/g时,比容量为23.1 mAh/g。NiFe_2O_4//NiFe_2O_4水系对称电池也具有一定的循环寿命,在500次充放电循环后,比容量仍能维持在最大比容量的90%。通过XRD和毒性浸出实验的检测分析,经过500次充放电循环后,NiFe_2O_4仍表现出良好的稳定性,可视为一般的工业废物。
[Abstract]:In recent years, due to the rapid development of industry and agriculture, the problem of environmental pollution is becoming more and more serious, and the problem of heavy metal pollution is particularly prominent. How to effectively solve the problem of heavy metal pollution has always been the research focus of the researchers. Because of its excellent physical and chemical properties, carbon based composites are very suitable for the treatment of heavy metal wastewater. In this paper, three kinds of carbon based composites rich in carboxyl were prepared: sheet Fe_3O_4/ carboxy carbon composites, TiO_2/ carboxy carbon composites, Fe_3O_4/ carboxy carbon composites, and three kinds of carbon based composites used in the photocatalytic reduction of Cr (VI) in chromium containing wastewater and copper ions in copper waste water. The heavy metal sludge based on NiFe_2O_4 was prepared by acid washing iron containing wastewater and electroplated nickel containing wastewater. The heavy metal sludge was assembled into a symmetrical battery of water system and the performance of the battery was studied. The main contents are as follows: (1) FeSO_4. 7H_2O, glucose and EDTA were used as raw materials, and a one-step synthesis by low temperature carbonization was made. Sheet like Fe_3O_4/ carboxyl carbon composites rich in carboxylic iron complexes. The sheet like Fe_3O_4/ carboxy carbon composites are dispersed in carbon slices with flaky amorphous carbon and Fe_3O_4 nanoparticles are evenly distributed in the carbon sheets and formed with carboxyl groups in EDTA to form iron carboxylic complexes (Fe~ (R-COO_) n~ (2-N) and Fe~ III (R-COO) _n~ (3-N)). There are a large number of carboxylic iron complexes in carbon composites, which make the material have excellent visible absorption energy. Under visible light, the Fe (II) /Fe (III) photocatalytic cycle between Fe~ II (R-COO) _n~ (2-N) and Fe~ III (R-COO) _n~ (3-N) makes the flaky Fe_3O_4/ carboxy carbon composites have excellent visible light photocatalytic reduction Cr (VI) capacity. In addition, after the reaction was completed, the Fe_3O_4/ carboxyl carbon composites could be separated by magnetic separation. (2) the TiO_2/ carboxyl carbon composites were synthesized with four butyl titanate, glucose and EDTA as raw materials by low temperature carbonization. Through the characterization of Raman, SEM, EDS and TEM, it was proved that the TiO_2/ carboxyl carbon composite was dispersed uniformly in the nanometer TiO_2 particles in the tablet. The structure in amorphous carbon is shown by FT-IR and XPS spectra. It is proved that the TiO_2/ carboxyl carbon composite contains a large number of carboxyl groups, and the TiO_2/EDTA complex,.TiO_2/ carboxyl carbon composite, has excellent visible absorption properties and photocatalytic reduction of Cr (VI) ability with TiO_2 particles. Under visible light, TiO_2/EDTA complexes pass through the ligand to the ligand. The photocatalytic reduction of Cr (VI) was realized by the charge transfer process (ligand-to-metal charge transfer, LMCT). (3) Fe_3O_4/ carboxyl carbon composite was synthesized by one step low temperature carbonization with FeSO_4 7H_2O and sodium gluconate. The carboxyl group in sodium gluconate and Fe (II) coordination formed a carboxylic acid iron complex. During the process, partial carboxyl iron complexes are heated to Fe_3O_4, and a large number of carboxyl groups remain in amorphous carbon and carboxyl rich in.Fe_3O_4/ carboxyl carbon composites are favorable for the adsorption of Cu (II) on the adsorption of.Fe_3O_4/ carboxyl carbon composites in water Cu (II), and the maximum adsorption capacity is 66.67 mg/g. with Fe_3O_4/ carboxyl carbon composite The adsorption kinetics and thermodynamics were studied as adsorbents. In various kinetic and isotherm models, the quasi two stage kinetic model and the Langmuir model were more consistent with the adsorption process of Fe_3O_4/ carboxy carbon composites on Cu (II). After the adsorption, the Fe_3O_4/ carboxyl carbon composites could be compound by magnetic separation of.Fe_3O_4/ carboxyl carbon. The material has excellent stability and can be recycled in acid solution. (4) the heavy metal sludge based on NiFe_2O_4 is obtained by neutralization and precipitation and hydrothermal reaction. The heavy metal sludge based on NiFe_2O_4 is used as the electrode material to construct NiFe_2O_4//NiFe_2O_4 water. When the discharge current density is 0.5 A/g, the symmetric cell of Ni Fe2O4//NiFe_2O_4 water system also has a certain cycle life when the discharge current density is 23.1 mAh/g.NiFe_2O_4//NiFe_2O_4. After the 500 charge discharge cycle, the specific volume can still be maintained at the maximum specific capacity of 90%. through XRD and. After testing and analysis of toxic leaching experiments, after 500 charge and discharge cycles, NiFe_2O_4 still showed good stability, which could be regarded as a general industrial waste.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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