BiOCl负载松针生物炭复合材料的制备及光催化降解性能研究

发布时间：2018-06-24 04:58

本文选题：生物炭 + 松针　；参考：《江苏大学》2017年硕士论文

【摘要】：随着经济的发展,水污染问题日渐加剧,目前对于去除水中污染物应用最广泛的是光催化降解法。在广泛应用的光催化材料中,BiOCl稳定性较好且无毒,具有特殊的层级结构和电子特性,在治理环境中染料废水污染具有较好的应用价值。但是BiOCl的禁带宽度较大,不能在可见光下被激发,易团聚分散性差等缺点。因此需要对其进行进一步的改性研究。在众多的改性方法中,与电子受体材料相耦合是比较常见的方法,生物炭就是近年来研究较热的电子受体材料,具有良好的电子传导性,可提高电子空穴对的分离效率。同时,由于其丰富的孔隙结构及较大的比表面积,在催化剂载体方面也被广泛研究,因此,将生物炭与BiOCl相结合应用于光催化领域中将有重要的应用前景。本文基于BiOCl/C催化材料进行了改性修饰,具体研究如下:首先,将松针进行预处理后通过管式炉煅烧制备成松针生物炭,经盐酸处理后用甲苯对其进行表面改性制成改性松针生物炭。然后以甲醇为溶剂,用溶剂热法制备花状BiOCl,再与改性松针生物炭通过管式炉煅烧进行复合,得到BiOCl/C二元复合材料,通过调整BiOCl与C的质量比来确定光催化降解效率最好的BiOCl/C复合材料。通过SEM、TEM、PL等分析测试手段对BiOCl/C复合材料进行分析研究,通过在紫外光下对RhB溶液进行光降解实验得出结论,BiOCl与C的质量比为3:4的BiOCl/C复合材料对RhB溶液展现出最佳的光降解效率,并通过机理实验提出了BiOCl/C复合材料降解RhB溶液的光降解机理。但由于其在可见光下的光催化降解效率不高,因此需要对其进行进一步改性研究。其次,通过在紫外光下光催化还原制备了Ag/BiOCl复合光催化剂,然后通过管式炉煅烧制备了Ag/BiOCl/C三元复合光催化剂。其中Ag:BiOCl:C的质量比为0.75:3:4时的复合光催化剂在光催化降解实验中显示出了最好的光催化降解活性。同样通过SEM、TEM以及电化学测试等分析测试手段对Ag/BiOCl/C三元复合材料进行分析研究,并通过机理探讨实验提出了Ag/BiOCl/C对RhB溶液的光降解机理。该复合光催化剂利用了贵金属Ag的表面等离子体共振效应,Ag作为电子供体,BiOCl作为电子传输媒介,而生物炭作为电子受体,提升了在光降解过程中光生电荷载流子的分离效率,提高了Ag/BiOCl/C的光催化性能。最后,先合成出AgCl/BiOCl异质结复合光催化材料,然后在紫外光下进行部分还原后得到Ag/AgCl/BiOCl复合光催化剂,再通过管式炉煅烧即可得到Ag/AgCl/BiOCl/C四元复合光催化剂。在可见光照射条件下,通过Ag/AgCl/BiOCl/C对RhB溶液进行光降解的实验得出结论,Ag/AgCl/BiOCl/C(S3)样品展现出了最好的降解活性。在进行了SEM、XRD、TEM、XPS、EDS、PL、DRS、电化学测试等表征及机理探讨实验后,提出了光催化降解过程的机理。该光催化剂中AgCl与BiOCl之间形成了异质结,当有可见光存在时,利用贵金属Ag的表面等离子体共振效应作为电子供体,产生的激发态电子通过AgCl和BiOCl转移到作为电子受体的导体的生物炭上,加强了光生电荷载流子的分离。这一系列的作用使该复合光催化剂在可见光区的光响应范围得到了进一步的扩展,进一步提高了对太阳光谱中可见光的利用。
[Abstract]:With the development of the economy, the problem of water pollution is becoming more and more serious. At present, photocatalytic degradation is the most widely used to remove pollutants in water. In the widely used photocatalytic materials, BiOCl has good stability and non-toxic. It has special hierarchical structure and electronic characteristics. It has a good application value in the treatment of dye wastewater pollution in the environment. However, the band gap of BiOCl is large and can not be excited in visible light, and it is easy to reunite with poor dispersion. Therefore, it needs to be further modified. In many modification methods, the coupling of electron acceptor materials is a common method. Biological carbon is a hot electron acceptor material in recent years, and it is good. The electronic conductivity can improve the separation efficiency of the electron hole pair. At the same time, because of its rich pore structure and large specific surface area, it is also widely studied in the catalyst carrier. Therefore, the application of biological carbon and BiOCl in the field of photocatalysis will have important prospects. In this paper, the BiOCl/C catalyst has been modified. First, the pine needle bio carbon was prepared by calcining the pine needle through a tube furnace, and the modified pine needle biological charcoal was made by the surface modification of toluene after treatment by hydrochloric acid. Then the flower like BiOCl was prepared by the solvent heat of methanol, and then burned with the modified pine needle bio carbon through the tube furnace. The BiOCl/C two element composite was obtained. The BiOCl/C composites with the best photocatalytic degradation efficiency were determined by adjusting the mass ratio of BiOCl to C. The BiOCl/C composites were analyzed by SEM, TEM, PL and other analytical methods. The results of the RhB solution under ultraviolet light were obtained, and the quality of BiOCl and C was obtained. The best photodegradation efficiency of RhB solution was shown to RhB solution than the BiOCl/C composite of 3:4. The mechanism of photocatalytic degradation of RhB solution by BiOCl/C composites was proposed through the mechanism experiment. However, the photocatalytic degradation efficiency under visible light was not high. Ag/BiOCl composite photocatalyst was prepared by chemical reduction, and then Ag/BiOCl/C three element composite photocatalyst was prepared by calcining tube furnace. The best photocatalytic degradation activity of Ag:BiOCl:C was shown in the photocatalytic degradation experiment when the mass ratio of 0.75:3:4 was 0.75:3:4. The same sample was analyzed by SEM, TEM and electrochemical testing. The Ag/BiOCl/C three element composite was analyzed by means of testing, and the mechanism of photodegradation of RhB solution by Ag/BiOCl/C was proposed through the mechanism. The composite photocatalyst made use of the surface plasmon resonance effect of precious metal Ag, Ag as an electron donor, BiOCl as a transmission medium, and biological carbon as an electron acceptor. The separation efficiency of photogenerated charge carrier was raised during the photodegradation process, and the photocatalytic performance of Ag/BiOCl/C was improved. Finally, AgCl/BiOCl heterojunction composite photocatalyst was synthesized first, then the Ag/AgCl/BiOCl composite photocatalyst was obtained after partial reduction under UV light, and then Ag/AgCl/BiOCl/C four yuan could be obtained by calcining the tube furnace. Under the condition of visible light irradiation, the results of the photodegradation of RhB solution by Ag/AgCl/BiOCl/C showed that the Ag/AgCl/BiOCl/C (S3) samples showed the best degradation activity. After the characterization and mechanism of SEM, XRD, TEM, XPS, EDS, PL, DRS, electrochemical testing and other experiments, the photocatalytic degradation process was proposed. A heterojunction is formed between AgCl and BiOCl in the photocatalyst. When the visible light exists, the surface plasmon resonance effect of the precious metal Ag is used as an electron donor. The excited electrons generated by AgCl and BiOCl are transferred to the biological carbon as the conductor of the electron acceptor. The separation of the light generated charge carrier is strengthened. The action of the column further expands the light response range of the composite photocatalyst in the visible light region, and further improves the use of visible light in the solar spectrum.
【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】：O643.36

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