磷酸锆复盐的微波制备和可见光催化印染废水的应用

发布时间：2018-10-30 06:52

【摘要】：光催化是一种将太阳光能转化为化学能和电能的技术,它可以直接利用太阳光降解水中的各种污染物,具有低成本、无污染、无选择性和可重复利用等优点。采用光催化技术降解处理印染废水是一种简单便捷的方法。然而,目前常用的光催化剂多为宽禁带半导体材料,这种催化剂仅在紫外光下具有光催化作用,不能高效利用自然光。针对上述问题,制备可见光光催化剂成为光催化领域的核心问题。本论文运用微波辅助加热法在开放体系下制备磷酸锆镍和磷酸锆锰两种材料,探究制备磷酸锆镍和磷酸锆锰的最佳原料及工艺条件,以及二者对有机染料的可见光光催化性能。本文采用了氧氯化锆、氟化铵、磷酸二氢钠以及氯化镍或氯化锰为起始原料,采用多种表面活性剂作为模板剂,在一定的反应pH值和温度等条件下进行微波加热反应,制备磷酸锆镍和磷酸锆锰。论文分别探讨了磷源、反应物比例、反应物浓度、反应pH值、反应温度以及三种表面活性剂PVP-K30、CTAB和SDS对制备磷酸锆镍和磷酸锆锰的影响。采用XRD、ICP、XPS、SEM(FESEM)、TG和UV-Vis等多种手段对磷酸锆镍和磷酸锆锰的物相、元素含量、元素价态、表面形貌、结晶水含量、带隙宽度等进行表征。以Zr OCl_2、NH_4F、Na H_2PO_4和Ni Cl_2为起始原料,反应液中[Zr4+]为0.005mol/L,其余反应物的浓度以Zr:Ni:F:P=1:1:6:20的比例混合,通过微波加热法在90℃和常压条件下反应30min,可制备得到线团形貌的磷酸锆镍。当反应液中分别加入三种表面活性剂0.59g PVP-K30、0.04g CTAB和0.29g SDS时,均可制备得到形貌规则的磷酸锆镍。磷源、反应pH值、反应物比例和反应物浓度是影响磷酸锆镍制备的重要因素,均决定着是否可以制备得到磷酸锆镍。当磷源或反应pH值改变时,产物无规则的形貌。当锆镍比高于3时,产物为片球形的混合物。磷锆比低于10时,产物无规则的形貌。氟锆比高于10时,产物为磷酸镍。当反应物浓度过高,产物为混合物。而反应温度和表面活性剂则影响磷酸锆镍的颗粒尺寸和均匀程度,对形貌也略有影响。随着反应温度升高,磷酸锆镍颗粒逐渐生长,形貌逐渐规整,尺寸大小逐渐均匀。加入表面活性剂后,可以降低产物的颗粒尺寸。其中,PVP-K30和CTAB对颗粒尺寸增长的抑制能力比SDS大。添加PVP-K30、CTAB和SDS作为模板剂有助于制备得到磷酸锆锰,并且可以得到多种形貌。起始原料Zr OCl_2、NH_4F、Na H_2PO_4和Mn Cl_2以Zr:Mn:F:P=1:1:6:20的比例混合,分别加入0.55g PVP-K30、0.04g CTAB或0.29g SDS,在90℃和常压条件下微波加热30 min,可制备得到磷酸锆锰。PVP-K30条件下制备的磷酸锆锰为片球状,CTAB条件下制备的磷酸锆锰为刺球状,SDS条件下制备的磷酸锆锰为片球状。将制备的磷酸锆镍和磷酸锆锰加入模拟印染废水的一定浓度的罗丹明B(Rh B)或亚甲基兰(MB)两种染料溶液中,在光催化下反应一定时间,测定最大吸收波长对应的吸光度,计算出染料的脱色率,讨论二者在可见光下对有机污染物的光催化性能。结果表明:磷酸锆镍对MB的可见光光催化效果最高可达49.0%,磷酸锆镍对Rh B的可见光光催化效果最高可达11.3%。磷酸锆镍对MB的可见光光催化效果优于Rh B。这可能是受到染料分子结构的影响,MB分子结构较小,有利于吸附到磷酸锆镍上进行催化降解反应。通过催化机理讨论可知,·OH、h~+和·O_2~-是参与染料降解的活性物质,其中·OH是主要活性物质。磷酸锆锰对Rh B的可见光光催化效果最高可达18.0%。研究表明,磷酸锆镍和磷酸锆锰均具有一定的可见光光催化性能。本课题采用微波辅助加热法制备出多种形貌的磷酸锆镍和磷酸锆锰,并应用于可见光催化降解Rh B或MB染料,结果表明,磷酸锆镍和磷酸锆锰具有可见光光催化性能。采用的微波辅助的制备方法具有反应条件温和以及操作简单等特点,同时有利于形成形貌规整的产物,为相关材料的制备提供了参考。
[Abstract]:Photocatalysis is a technology for converting sunlight energy into chemical energy and electric energy, and can directly utilize sunlight to degrade various pollutants in water, and has the advantages of low cost, no pollution, no selectivity and reusability and the like. Photocatalytic degradation of printing and dyeing wastewater is a simple and convenient method. However, the commonly used photocatalyst is a wide forbidden zone semiconductor material, and the catalyst has photocatalysis effect only under ultraviolet light, and natural light can not be efficiently utilized. Aiming at the above problems, a visible light photocatalyst is prepared into a core problem in the photocatalysis field. In this paper, two kinds of materials, namely nickel phosphate, nickel phosphate and manganese phosphate were prepared under the open system by microwave-assisted heating, and the best raw materials and technological conditions for preparing manganese phosphate and manganese phosphate were investigated. In this paper, a variety of surfactants are used as template agents to prepare nickel phosphate and manganese phosphate by microwave heating under certain conditions such as pH value and temperature. The effects of phosphorus source, reactant ratio, reactant concentration, reaction pH value, reaction temperature and three kinds of surfactant PVP-K30, CTAB and SDS on the preparation of nickel phosphate and manganese phosphate were discussed. XRD, ICP, XPS, SEM (FESEM), TG and UV-Vis, etc. were used to characterize the contents, elemental contents, valence state, surface morphology, metal content and gap width of manganese phosphate and manganese phosphate. Using Zr OCl _ 2, NH _ 4F, Na H _ 2PO _ 4 and Ni Cl _ 2 as starting materials,[Zr4 +] in the reaction solution is 0. 005mol/ L, the concentration of the remaining reactants is mixed with the proportion of Zr: Ni: F: P = 1: 1: 6: 20. Three kinds of surfactants were added to the reaction solution respectively. 59g PVP-K30, 0.04g CTAB and 0. 29g SDS could be used to prepare nickel phosphate with regular morphology. Phosphorus source, reaction pH, reactant ratio and reactant concentration are important factors affecting the preparation of nickel phosphate. When the phosphorus source or the reaction pH value changes, the morphology of the product plume is observed. When the nickel-to-nickel ratio is higher than 3, the product is a spherical mixture. When the phosphorus-to-phosphorus ratio is less than 10, the morphology of the product plume is improved. When the fluorine content ratio is higher than 10, the product is nickel phosphate. When the concentration of the reactants is too high, the product is a mixture. and the reaction temperature and the surface active agent affect the particle size and the uniformity of the nickel phosphate, and have slight influence on the morphology. As the temperature of the reaction increased, the nickel-phosphate particles were gradually grown, the morphology was gradually regular, and the size was gradually uniform. After addition of the surfactant, the particle size of the product can be reduced. Among them, the inhibition ability of PVP-K30 and CTAB to particle size growth was larger than that of SDS. The addition of PVP-K30, CTAB and SDS as a template aid in the preparation of manganese phosphate, and various morphology can be obtained. The starting materials Zr OCl _ 2, NH _ 4F, Na H _ 2PO _ 4 and Mn Cl _ 2 were mixed at a ratio of Zr: Mn: F: P = 1: 1: 6: 20, respectively. The manganese phosphate prepared under the condition of PVP-K30 is spherical, and the manganese phosphate prepared under the CTAB condition is spherical, and the manganese phosphate prepared under the conditions of SDS is spherical. adding the prepared nickel phosphate and manganese phosphate into two dye solutions of a certain concentration of simulated printing and dyeing wastewater, reacting under photocatalysis for a certain time, measuring the absorbance corresponding to the maximum absorption wavelength, and calculating the decoloring rate of the dye, The photocatalytic properties of both organic pollutants under visible light were discussed. The results showed that the photocatalytic effect of nickel phosphate on MB was up to 49. 0%, and the photocatalytic effect of nickel phosphate on Rh B was up to 11. 3%. The photocatalytic effect of nickel phosphate on MB is better than Rh B. This may be influenced by the molecular structure of dyes, the molecular structure of MB is small, and it is favorable for adsorption to the catalytic degradation reaction on nickel phosphate. It is found that 路 OH, h ~ + and 路 O _ 2 ~-are active substances involved in dye degradation, and 路 OH is the main active material. The photocatalytic effect of manganese phosphate on Rh B was up to 18. 0%. The results showed that both nickel phosphate and manganese phosphate had certain visible light photocatalytic activity. In this paper, a microwave-assisted heating method was used to prepare various morphologies of nickel phosphate and manganese phosphate, and it was used to catalyze the degradation of Rh B or MB dyes by visible light. The results showed that nickel phosphate and manganese phosphate had visible photocatalytic activity. The microwave-assisted preparation method provided by the invention has the characteristics of mild reaction condition, simple operation and the like, is favorable for forming a product with regular appearance, and provides a reference for the preparation of related materials.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X791;O643.36

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