高效钛基复合电极的制备及其光电催化性能研究
发布时间：2018-07-24 17:41
【摘要】：有机物污染是目前我国面临的最大环境保护问题之一,染料废水作为高分子聚合物,其浓度大、色度高、可生化性差,缺乏有效的处理方法,成为了水处理领域的难点,对人类和环境造成了极大的危害。光催化技术作为高级氧化技术的一种,为我们提供了高效治理有机废水的途径。此技术常采用纳米二氧化钛作为催化剂,这是因为其化学性质稳定、无毒,并且材料成本低。然而纳米材料存在回收难度大、可重复利用率低。因此本论文研究了新型TiO_2碳布电极和3D-TiO_2纳米管电极的制备及其改性,分析材料形成机理、物理化学性能和光电催化性能,并分析光电催化降解甲基橙的各个影响因素,为光电催化去除有机污染物技术的实际应用提供理论依据,主要研究成果如下:(1)水热法合成以碳布为基底的TiO_2电极:①通过比较光电流初步推断光电催化活性,调节温度、时间、钛源等参数优化电极性能。确定合成电极最佳实验条件为:前驱液浓度分别为0.6mL钛酸异丙酯、10mL盐酸溶液、0.2 g十六烷基三甲基溴化铵、0.34mL乙二醇;水热温度150℃;反应时间5h。②所合成的材料为金红石型TiO_2纳米簇颗粒电极,其物理化学性能稳定,导电性优越,在紫外光下施加+0.7 V的偏压,2 h光电降解5 mg/L甲基橙去除率为98%,且重复实验7次时2 h降解率仍然大于85%。(2)采用电化学阳极氧化法,以钛丝网作为基底材料合成3D-TiO_2纳米管阵列(3D-TNAs)电极。①最佳阳极氧化实验条件为:溶剂为V乙二醇：V 水=1:1,0.5wt%NH4F,阳极氧化电压20V,超声振荡传质氧化90min。制得TiO_2纳米管,与同一实验条件下以钛板为基底阳极氧化电极比较,电化学活性面积、光电流、光电催化降解反应速率常数分别提高了2倍、1倍和2倍。②通过连续离子层吸附反应,将合成出的3D-TNAs电极分别浸渍于乙醇:H_2O=1:1为溶剂的乙酸锌、乙酸镉、Na2S溶液,获得异质节负载改性电极。最佳实验条件是:浓度分别为0.01 mol/L,负载次数12次,煅烧条件是氮气气氛以2℃/min升温至500℃保持2h。在负载硫化物前,阳极氧化电极浸渍于1 mg/L氧化石墨烯(GO),再负载硫化物,氧化石墨烯的存在使体系形成Z形模型,明显提高了光电催化性能。③硫化物改性电极在实际废水降解测试效果不理想,稳定性有待提高。(3)采用溶液蒸发自组装法(EISA),制备金红石-锐钛矿混相二氧化钛3D-TNAs电极材料,①最佳实验条件为:P123为模板剂,陈化2d,在阳极氧化后直接浸到溶胶凝胶中一起陈化干燥,以5℃/min升温速率升到500℃,煅烧2h合成出3D-TNAs/TiO_2(EISA)电极,光电流较3D-TNAs电极提高2.5倍,光电耦合性能在+0.8 V最佳。②对5 mg/L的MO进行光催化效果明显,在2h汞灯照射下施加+0.8 V偏压,同样实验条件重复6次对MO的去除率仍大于98%。③光电催化降解率受有机污染物浓度、催化剂浓度、反应温度、光强、电解质浓度的影响。在电解质浓度一致下,低浓度污染物光电去除率符合一级动力学,-ln(C_t/C_0)=kt,且反应速率常数k与污染物初始浓度呈指数关系k=aC_0~(n1),与反应温度符合阿伦尼乌斯公式k=Aexp(-Ea/RT),与光强符合指数关系k=aIn3,与电极材料面积符合k=b(A_sD)~n,总结反应速率常数与各个参数的关系为k = A·e~(Ea/RT)·C_0~(n1)·I~(n2)·(A_sD)~(n3),确定污染物浓度与时间的关系为C_t/C_0=e~(-kt)=e~(-A·e~(-Ea/RT)·C_0~(n1)·I~(n2)·(A_sD)~(n3)·t)。
[Abstract]:Organic matter pollution is one of the biggest environmental protection problems in China. As a polymer, dye wastewater is a polymer with high concentration, high chromaticity, poor biodegradability and lack of effective treatment. It has become a difficult problem in the field of water treatment and has caused great harm to human and environment. Photocatalytic technology is a kind of advanced oxidation technology. Nanoscale titanium dioxide is often used as a catalyst. This is because its chemical properties are stable, nontoxic, and the cost of materials is low. However, the recovery of nanomaterials is difficult and the reutilization rate is low. Therefore, the new TiO_2 carbon electrode and 3D-TiO_2 nanotube are studied in this paper. The preparation and modification of the electrode, the formation mechanism of the material, the physical and chemical properties and the photoelectric catalytic properties are analyzed, and the various influence factors of the photocatalytic degradation of methyl orange are analyzed, and the theoretical basis for the application of the photoelectrocatalysis to remove the organic pollutants is provided. The main research results are as follows: (1) the synthesis of TiO_2 electricity based on the carbon cloth by hydrothermal method is as follows. The optimum experimental conditions of synthetic electrode are: 0.6mL isopropyl titanate, 10mL hydrochloric acid solution, 0.2 g sixteen alkyl ammonium bromide, 0.34mL ethylene glycol, 150 C hydrothermal temperature and 5 reaction time, respectively. H. (2) is a rutile type TiO_2 nanocluster electrode. Its physical and chemical properties are stable, electrical conductivity is superior, +0.7 V bias is applied under UV light, 2 h photodegradation 5 mg/L methyl orange removal rate is 98%, and the 2 h degradation rate is still greater than 85%. (2) by electrochemical anodic oxidation, with titanium screen as the base. 3D-TiO_2 nanotube array (3D-TNAs) electrode was synthesized by the substrate. (1) the optimum anodic oxidation experiment conditions were as follows: the solvent was V ethylene glycol: V water =1:1,0.5wt%NH4F, anodic oxidation voltage 20V, TiO_2 nanotube produced by ultrasonic oscillation mass transfer oxidation 90min., compared with the titanium plate as the base anode oxidation electrode under the same experimental condition, the electrochemical active area and light. The rate constants of the current and photoelectric catalytic degradation were increased by 2 times, 1 times and 2 times respectively. By continuous ion layer adsorption, the synthesized 3D-TNAs electrodes were impregnated with ethanol: H_2O=1:1 as solvent, zinc acetate, cadmium acetate and Na2S solution. The optimum experimental condition was that the concentration was 0.01 mol/L, respectively. The time of loading is 12 times. The conditions of calcining are that the nitrogen atmosphere is heated at 2 /min to 500 C to maintain 2h. at the load of sulfide, and the anode oxidation electrode impregnated with 1 mg/L graphene oxide (GO), then the sulphide is loaded, and the presence of graphene oxide makes the system form a Z shape model and obviously improves the photocatalytic performance. 3. Sulfide modified electrode is reduced to the actual wastewater. The results of the solution are not ideal, and the stability needs to be improved. (3) using the solution evaporation self assembly (EISA) method to prepare the rutile anatase titanium dioxide 3D-TNAs electrode material. (1) the optimum experimental conditions are P123 as a template, aging 2D, and drying in gelatin gel directly after anodizing, and rising to 500 at the temperature of /min at 5. The 3D-TNAs/TiO_2 (EISA) electrode was synthesized by calcined 2h, the photoelectric current was 2.5 times higher than that of the 3D-TNAs electrode, and the photoelectric coupling performance was the best in +0.8 V. 2. The photocatalytic effect on MO of 5 mg/L was obvious, the +0.8 V bias was applied under the 2H mercury lamp, and the removal rate of the MO was still greater than the photoelectric catalytic degradation rate 6 times more than the photoelectric catalytic degradation rate. The effect of dye concentration, catalyst concentration, reaction temperature, light intensity and electrolyte concentration. Under the consistency of electrolyte concentration, the photoelectric removal rate of low concentration pollutants accords with the first order kinetics, -ln (C_t/C_0) =kt, and the reaction rate constant k is exponentially related to the initial concentration of pollutants k= aC_0~ (N1), and the reaction temperature conforms to the Arrhenius formula k=Aexp (-Ea/). RT), in accordance with the exponential relationship with the light intensity, k=aIn3, and the area of the electrode material in line with the k=b (A_sD) ~n. The relation between the reaction rate constant and the parameters is k = A / e~ (Ea/RT) C_0~ (N1) and I~.
【学位授予单位】：中央民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703
本文编号：2142148
[Abstract]:Organic matter pollution is one of the biggest environmental protection problems in China. As a polymer, dye wastewater is a polymer with high concentration, high chromaticity, poor biodegradability and lack of effective treatment. It has become a difficult problem in the field of water treatment and has caused great harm to human and environment. Photocatalytic technology is a kind of advanced oxidation technology. Nanoscale titanium dioxide is often used as a catalyst. This is because its chemical properties are stable, nontoxic, and the cost of materials is low. However, the recovery of nanomaterials is difficult and the reutilization rate is low. Therefore, the new TiO_2 carbon electrode and 3D-TiO_2 nanotube are studied in this paper. The preparation and modification of the electrode, the formation mechanism of the material, the physical and chemical properties and the photoelectric catalytic properties are analyzed, and the various influence factors of the photocatalytic degradation of methyl orange are analyzed, and the theoretical basis for the application of the photoelectrocatalysis to remove the organic pollutants is provided. The main research results are as follows: (1) the synthesis of TiO_2 electricity based on the carbon cloth by hydrothermal method is as follows. The optimum experimental conditions of synthetic electrode are: 0.6mL isopropyl titanate, 10mL hydrochloric acid solution, 0.2 g sixteen alkyl ammonium bromide, 0.34mL ethylene glycol, 150 C hydrothermal temperature and 5 reaction time, respectively. H. (2) is a rutile type TiO_2 nanocluster electrode. Its physical and chemical properties are stable, electrical conductivity is superior, +0.7 V bias is applied under UV light, 2 h photodegradation 5 mg/L methyl orange removal rate is 98%, and the 2 h degradation rate is still greater than 85%. (2) by electrochemical anodic oxidation, with titanium screen as the base. 3D-TiO_2 nanotube array (3D-TNAs) electrode was synthesized by the substrate. (1) the optimum anodic oxidation experiment conditions were as follows: the solvent was V ethylene glycol: V water =1:1,0.5wt%NH4F, anodic oxidation voltage 20V, TiO_2 nanotube produced by ultrasonic oscillation mass transfer oxidation 90min., compared with the titanium plate as the base anode oxidation electrode under the same experimental condition, the electrochemical active area and light. The rate constants of the current and photoelectric catalytic degradation were increased by 2 times, 1 times and 2 times respectively. By continuous ion layer adsorption, the synthesized 3D-TNAs electrodes were impregnated with ethanol: H_2O=1:1 as solvent, zinc acetate, cadmium acetate and Na2S solution. The optimum experimental condition was that the concentration was 0.01 mol/L, respectively. The time of loading is 12 times. The conditions of calcining are that the nitrogen atmosphere is heated at 2 /min to 500 C to maintain 2h. at the load of sulfide, and the anode oxidation electrode impregnated with 1 mg/L graphene oxide (GO), then the sulphide is loaded, and the presence of graphene oxide makes the system form a Z shape model and obviously improves the photocatalytic performance. 3. Sulfide modified electrode is reduced to the actual wastewater. The results of the solution are not ideal, and the stability needs to be improved. (3) using the solution evaporation self assembly (EISA) method to prepare the rutile anatase titanium dioxide 3D-TNAs electrode material. (1) the optimum experimental conditions are P123 as a template, aging 2D, and drying in gelatin gel directly after anodizing, and rising to 500 at the temperature of /min at 5. The 3D-TNAs/TiO_2 (EISA) electrode was synthesized by calcined 2h, the photoelectric current was 2.5 times higher than that of the 3D-TNAs electrode, and the photoelectric coupling performance was the best in +0.8 V. 2. The photocatalytic effect on MO of 5 mg/L was obvious, the +0.8 V bias was applied under the 2H mercury lamp, and the removal rate of the MO was still greater than the photoelectric catalytic degradation rate 6 times more than the photoelectric catalytic degradation rate. The effect of dye concentration, catalyst concentration, reaction temperature, light intensity and electrolyte concentration. Under the consistency of electrolyte concentration, the photoelectric removal rate of low concentration pollutants accords with the first order kinetics, -ln (C_t/C_0) =kt, and the reaction rate constant k is exponentially related to the initial concentration of pollutants k= aC_0~ (N1), and the reaction temperature conforms to the Arrhenius formula k=Aexp (-Ea/). RT), in accordance with the exponential relationship with the light intensity, k=aIn3, and the area of the electrode material in line with the k=b (A_sD) ~n. The relation between the reaction rate constant and the parameters is k = A / e~ (Ea/RT) C_0~ (N1) and I~.
【学位授予单位】：中央民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703
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