Preparation, Characterization And Properties Of Gypsum Base Acidic Composites

Due to a variety of geometric and electronic structure, and excellent redox properties and stability, Polyoxometalates(referred to POMs) are easy to modulate and structural modifications in the atomic and molecular level. Meanwhile, POMs are environment-friendly functional materials in the field of catalysis, medicine, magnetic and optical materials with a wide range of applications. However, POMs have small specific surface area, which is not easy to separate and recover, leading to drawback difficulties and limiting its application. Combining polyoxometalates with other functional materials, which is an important way to break POMs application bottlenecks. In this paper, we use the main body of graphite oxidation process to synthesize graphene-based acid(POMs / GS) composites with situ-synthesis method. Also, we discussed experimental results in different reaction conditions, optimized parameters of the synthesis process, and prepared a series of graphene-based POMs composites. Infrared spectroscopy(FT-IR), X- ray powder diffraction(XRD), Raman spectroscopy(Raman), scanning electron microscopy(SEM), Thermogravimetric Analysis(TG) and other technical means are used to indicate the composite structure. Cyclic voltammetry(CV) and oxidative desulfurization performance testing are also used to text its characteristics, electrochemical properties and catalytic oxidative desulfurization of the new composite materials were also discussed and further studied. The main work and research results of the paper are as follows:1. We prepared graphene-based Dawson type phosphomolybdate complex by means of situ-synthesis. Through experimental studies on the synthesis conditions, we choose and determine the optimum conditions and routes. The results show that when the low temperature intercalation time is 7h, temperature oxidation time is 40 min, the phosphomolybdic acid particles in the product, which could be uniformly distributed in the oxide layer of the graphene sheet, it has the complete structure of the graphene sheet and a relatively small surface defects.2. The synthesis of Graphene-based substituted phosphomolybdate composites. We select graphene and PMo V, PMo V etc. substituents as building blocks to 11 10 2 synthesize a series of substitution type phosphomolybdate graphene hybrid materials. The new material test results such as FT-IR, Raman, XRD, TG show that the composite material has perfect POMs structure, with fewer defects on the graphene sheets. The route we selected provides a moderate degree of oxidation process, also, the excellent effect of graphite. Thermal stability of the new materials compared with raw material has been greatly improved.3. Electrochemical properties of POMs/GS composites. Carbon paste electrodes were used, to prepare composites electrode using the legal system. Cyclic voltammetry experiments test results show that, the electrochemical properties of the composites are quite similar to the parent acid, cyclic voltammetry curves significantly show POMs’ electrochemical characteristics. So, this kind of composites is expected to have potential oxidation activity.4. Experimental study of catalytic oxidation desulfurization of the composites. We selected our materials as catalyst, H2O2 as oxidant to carry out the catalytic oxidation of dibenzo thiophene desulfurization experimental study. The results show that the catalytic dibenzothiophene desulfurization effect is obvious. Since the novel catalytic material is insoluble in the reaction system in polar organic solvent, the separation and recovery problems of catalysts are well resolved, which could reduce the production costs. Studies show that the new composite material can be reused. The new catalytic material has outstanding characteristics such as high catalytic activity, selectivity and longer life.