The Study Of Photocatalytic Properties Of Doped Diopside

In this paper, we studied one of the major minerals of titanium slag---diopside. diopside was synthesized by solid-phase synthetic method. Characteristics of diopside absorbing methylene blue under the dark reaction conditions. Photocatalytic activity of diopside was evaluated. Doping of metal ions on diopside was studied. Photocatalytic mechanisms of methylene blue on diopside were preliminarily studied. This would play an important role in studying the photocatalytic properties of the titanium-bearing blast furnace slag, and provide theoretical basis for the slag as photocatalytic materials, and have great significance for its rational use.With CaCO3, MgO and SiO2as raw materials, diopside(MgO·CaO·2SiO2) was synthesized by solid-phase synthetic method. We got the best temperature to synthesis of diopside by Experimental. By the analysis of XRD, SEM, FTIR and UV-vis, the results showed that pure diopside could be synthesized above1400℃and3h.We preliminary studied the adsorption characteristics of diopside in the dark reaction to the methylene blue and analyze the effect of the dosage of diopside to methylene blue adsorption. The results showed that:the diopside adsorption of methylene blue is in line with lungmuir type adsorption isotherm, with adsorption amount of0.835mg/g, and the diopside adsorption of methylene blue was chemical adsorption; during the adsorption of methylene blue chemical reactions happened. The adsorption could reach equilibrium of the desorption in0.5h. When the concentration of methylene blue solution was5mg·L-1, the adsorption removal could get up to31%.We studied the photocatalytic properties of methylene blue as a subject matter and determine the absorption curve and standard curve of methylene blue. We also determined the degradation conditions of methylene blue alone in UV light. The results showed that: methylene blue absorption peaked at the wavelength λ=664nm, concentration and absorbance at0～10mg/L range of linear relationship. The methylene blue had high rate of degradation between1h. When the illumination time of1h, the degradation rate is12%. One hour later, with the illumination time passing, the UV photocatalytic degradation rate of methylene blue was very slow, and degradation rate remains unchanged, which is balanced at about12%. Through researching the synthesis of pure diopside, we wanted to know if it has the photocatalytic performance. The results showed that:synthetic diopside mineral had photocatalytic degradation effect on methylene blue. Adding0.3g of diopside in the UV(365nm) irradiation4h made the initial concentration of5mg/L and reached equilibrium methylene blue solution degrade28%, except for UV irradiation on the degradation of methylene blue still could get up to16%; by this experimental studing, diopside has photocatalytic ability, but pure synthetic diopside photocatalytic efficiency is low.In the Fe3+-doped diopside modification experiment, we mainly focused on the impact of the amount of diopside doped to the photocatalytic performance. The results showed that:we used impregnated roasting method to prepare synthetic product which was iron diopside. The product is formed by iron elements replacing the elements in the diopside. Through the amount of different Fe3+-doped diopside to the methylene blue degradation repetitive experiment, we found that with the increasing of the amount of Fe3+-doped, doped diopside photocatalytic capacity improved, when the Fe3+doping was1.848%, the photocatalytic ability could achieve the strongest, the best degradation could reach91%, continuing to increase the amount of Fe3+doping, the photocatalytic effect was reduced.Ti-doped diopside modified experimental results showed that:Through the amount of different Ti-doped diopside to the methylene blue degradation repetitive experiment, as TiO2doping increasesing, the doped diopside photocatalytic capacity improved, when the TiO2doping at3%, the photocatalytic ability achieves the strongest with the best degradation which can reach76%, and continuing to increase the amount of TiO2doping, the photocatalytic effect is adversely reduced.