The Preparation Of Ni-doping Mangan Zinc Ferrite And The Study Of Evaluation Of Catalytic Degration

Organic wastewater seriously pollute the environment, despite the photocatalyst has advantages for the degradation of organic wastewater obviously, but the catalyst is easy to be poisoned and hard to recovery so that restricting the application of photocatalyst. This article uses the chemical coprecipitation to make Mn-Zn ferrite that having magnetic and calalytic properties, and the effect of p H, calcination temperature,calcination time on property of Mn-Zn ferrite by Uniform design method are discussed,then using the SPSS and Visual Fox Pro to fit to obtain the suitable preparation conditions. In order to improve the magnetic and catalytic properties of manganese zinc ferrite, This paper studies 6 kinds of rare metal ions(La3+、Ce3+、Cu²⁺、Ni²⁺、Co²⁺、Ti4+) doped to prepare Mn-Zn ferrite respectively, using SEM, XRD, BET and FT- IR to characterize the sample’s phase structure,VSM to analysis magnetic property,UV-VIS to detect absorption ability of ultraviolet visible light, and the effect of Mn-Zn ferrite of different elements doping through these data is evaluated. Through the performance of catalytic degradation of methylene blue, the influence of different doped on the properties of Mn-Zn ferrite is investigated. In order to proven the catalytic effect and magnetic ablity of Ni²⁺-doped Mn-Zn ferrite, the performance impact of different amount of Ni²⁺ doped on the Mn-Zn ferrite is discussed, and the catalytic ability, magnetic ability and surface structure of samples are also characterized. Using methylene blue as probe to evaluate the photocatalytic performance, Aniline as probe to evaluate the thermal catalytic performance. Combining with honeysuckle biomass resources of Chongqing, this paper discusses Mn-Zn ferrite apply on the catalytic liquefaction plant tissue preliminarily. It provide experimental basis to explore manganese zinc ferrite properties and its application. Experimental conclusion as follows:（1）By using uniform design method, selecting the optimum preparation conditions:p H is 7.1, calcination temperature is 1140 ℃, burning time is 3.0h. The optimal sample has spinel structure, the particle size is 62.65 nm, its constituent structure is Mn3Zn2Fe5O12.5 and containing groups of metal-oxygen and H-O, its saturation magnetization is 11.37 emu/g, and its ultraviolet visible absorption ability is stronger in the range of 300-600 nm,it can achieve visible light response and have magnetic energy for the solid-liquid separation.（2）The characteristic results of different ions doped show that: Doping does not affect the crystal structure of Mn-Zn ferrite,the absorption ability to the ultraviolet visible light in the order Ni²⁺（1.424）>Ti4+（1.415）>Co²⁺（1.398）>Cu²⁺（1.381）>Ce3+（1.343）>La3+（1.283）and the rate of catalytic degradation of methylene blue for 1.0h in the order Ni²⁺（49.85%）>Ti4+（48.66%）>Co²⁺（46.22%）>Cu²⁺（45.57%）>Ce3+（38.55%）>La3+（35.51%）; specific surface area in the order Ni²⁺（1.8492 m2�'g-1）>Ti4+（1.7702 m2�'g-1）>Cu²⁺（1.6936 m2�'g-1）>La3+（1.5879 m2�'g-1）>Co²⁺（1.5853 m2�'g-1）>Ce3+（1.4514 m2�'g-1）; grain size in the order Ti4+（43.55nm）<Ni²⁺（49.18 nm）<Co²⁺（49.98 nm）<Ce3+（51.13 nm）<La3+（57.57 nm）<Cu²⁺（63.18 nm）; saturation magnetization in the order Ti4+（11.17emu/g）>La3+（11.06 emu/g）>Co²⁺（10.11emu/g）>Ce3+（9.52 emu/g）>Ni²⁺（9.24 emu/g）>Cu²⁺（9.20 emu/g）; Ni²⁺ dopping Mn-Zn ferrite shows good performance in calalytic and magnetic properties and detects the concentration of Mn²⁺、Fe3+、Zn²⁺ after the catalytic reaction are 0.03 mg/L、0.98mg/L、 0.03 mg/L respectively, it sates that the preparation of catalyst is stable and reliable.（3） The characteristic results of different doping quantity from 0.20% to 1.00%of Ni²⁺ show that: saturation magnetization of 1.00% is 15.88emu/g as the highest;grain size increased with the quantity of doping; specific surface area of 0.20% is2.2385 m2�'g-1 as the maximum; the absorption ability to the ultraviolet visible light of0.40% is the strongest and the degradation rate of catalytic degradation of methylene blue can reach 54.23% for 1.0h.（4） The results of photocatalytic methylene blue of 0.40% Ni²⁺ doped Mn-Zn ferrite show that: when quality of catalyst is 0.100 g, the photocatalytic degradation of methylene blue of 10mg/L in the volume of 50 ml is the highest, as much as 63.11%under light for 3.0h. This is 1.28 times of the none-doping and increased 1.17 times of the blank. In the experiment of catalyst recycling, the degradation rate of catalyst for repeated use 5 times is 57.60%. It shows that the catalyst is stable and reliable, and can recycle many times. Mn-Zn ferrite meet first order kinetics for photocatalytic methylene blue.（5） The results of thermocatalytic aniline of 0.40% Ni²⁺ doped Mn-Zn ferrite show that: under a certain temperature, the catalyst is helpful to the degradation of aniline,and the degradation of aniline increased with increasing of the temperature and time;when quality of catalyst is 0.100 g, the degradation efficiency of aniline of 75mg/L was up to 72.47% under the condition of 130℃ for 2.h. This is 1.68 times of the blank and 1.54 times of the none-doped. Mn-Zn ferrite meet first order kinetics for thermocatalytic aniline.（6） The results of catalytic liquefaction leaf of honeysuckle show that: the catalyst can catalyze liquefaction of leaf of honeysuckle under the action of different solid-liquid ratio and liquefaction time, the liquefied rate of leaf of honeysuckle is29.61% when liquefaction time is 70 min, this is 1.45 times of the blank; the liquefied rate of leaf of honeysuckle is 31.1% when solid-liquid ratio is 12:1, this is 1.52 times of the blank; compared with no catalyst, the ions concentration deviation of Mn2 +、Fe2 +、Zn2 + of liquefied solution after the catalytic reaction are 0.03 mg/L、0.98 mg/L、0.03mg/L respectively, it sates that the preparation of catalyst is stable and reliable.