Construction Of Synergistically Adsorbing-photocatalytic System And Preparation Of Hierarchical Porous Nanosheet-assembled MgO Microrods

With the rapid development of science and technology and the continuousimprovement of people’s living standards, people’s requirements for the environmentare becoming higher. But environmental pollution has been more and more prominent,and impacting on people’s production and life badly. It’s extremely urgent todevelopment a new-style, environmental and high-efficiency method forenvironmental management. There are many ways to govern water pollution, andamong them photocatalytic degradation and adsorption are used widely. NanoscaleTiO2photocatalyst which is non-toxic and low-cost, has excellent catalytic activity,high oxidation ability and stable physical and chemical properties, etc. It sats at theheart of the field of photocatalysis, and is widely used. Adsorption is an important linkin the photocatalytic process, high specific surface area can improve the adsorptioncapacity, and promote the photocatalytic reactivity. That is means constructing thecollaborative system of adsorption-photocatalysis can improve photocatalytic effect.Nanoscale MgO adsorbent has the advantages of nontoxic, cheap and good adsorptioncapacity, can be used in the collaborative system of adsorption-photocatalysis as thecarrier with high adsorption capacity.In order to build the system with adsorption-photocatalysis synergy and highcatalytic activity at the same time, this paper explored the catalytic activity of theTiO2@@SiO2/glass powder firstly, and finded that although it could solve theproblem of recycling in the practical application but photocatalytic degradation effectwas Unsatisfactory. Therefore, this paper researched that the TiO2-NTs@@SiO2nanotubes replaced the TiO2@@SiO2/glass powder to using as the photocatalyst inthe photocatalytic collaborative system (TiO2-NTs@@SiO2/PS-MgO), andsystematically studied the effect of time and calcination temperature on the crystalstructure, morphology and photocatalytic performance in hydrothermally coatingorganic carbon layer. Adsorption is the prerequisite in photocatalytic degradation, thearticle also explored the advantages of the hierarchical porous magnesium oxidemicrorods with high adsorption capacity (PS-MgO) when replacing low melting point glass powder as carriers. Thus lay a solid foundation to get the material ofTiO2-NTs@@SiO2/PS-MgO, which has adsorption-photocatalysis synergy and highcatalytic activity eventually.Taking P25as the raw material, through the process of coating carbon layer andcoating silicon layer we could acquire the material of TiO2@C@SiO2. Taking the lowmelting point glass powder as a carrier, we prepared the TiO2@@SiO2/glass powderby melting method. Adsorption plays a very crucial role for photocatalyticdegradation rate. Therefore, the adsorption and photocatalytic performance of theTiO2@@SiO2/glass powder for Rhodamine B were explored.By changing the calcination temperature and the hydrothermal time duringcoating organic carbon layer, we discussed the effect on crystal form, morphology andphotocatalytic activity of TiO2-NTs@@SiO2, further optimized the chemicalmorphology freezing method, and acquired the photocatalyst of TiO2-NTs@@SiO2with good performance. In the condition of hydrothermal time with9h andcalcination temprature with650oC, the obtained TiO2-NTs@@SiO2could have goodtubular morphology, high anatase crystalline and fast photocatalytic degradation rate.Taking NH4HCO3solution and MgCl26H2O solution as raw material, throughhomogeneous precipitation, hydrothermal and calcination methods successfullysynthesized hierarchical porous magnesia nanosheets assembled microrods (PS-MgO).And PS-MgO has a large specific surface area (72m2/g), large pore volume,hierarchical porous structure, etc., which has a decisive influence on the adsorptionproperties. Congo red (CR) adsorption experiment show that after adsorption for120min, PS-MgO adsorption capacity reached392mg g-1，which is1.3times higher thanthat of the hierarchical hydroxide nanosheets assemb led microrods (S-Mg(OH)2), andis2.3times than magnesia microrods (P-MgO). PS-MgO exhibits superior adsorptionproperties, can be used as photocatalyst carrier for the TiO2-NTs@@SiO2to obtainhigher photocatalytic activity.