Study On Treatment Of Cr(?)Wastewater With Nitrogen-doped Titanium-bearing Blast Furnace Slag

At present,Cr(VI)wastewater treatment technology has the defects of high cost and easy to cause secondary pollution.With the development of photocatalytic technology,some progress has been made in the treatment of Cr(?)wastewater by using photocatalytic technology.However,the cost of catalyst which limits the development and utilization of related technologies is very high.At the same time,the titanium-bearing blast furnace slag of Pangang steel co.ltd.contains a lot of titanium resources.By doping and calcining,it will be used as a whole photocatalyst to reduce the cost of photocatalytic technology and make solid waste resources available,so as to achieve the goal of waste disposal.In this experiment,nitrogen-doped titanium-bearing blast furnace slag was prepared with the titanium-bearing blast furnace slag providedly in Pangang steel co.ltd.as raw material,the influence of chemical composition,structure and morphology,optical absorption capacity,nitrogen doping ratio and calcination temperature on the catalytic performance of Ti bearing blast furnace slag was analyzed by XRD,SEM,XRF,TG,UV-Vis-DRS and other methods.The catalytic effect of N-TBBFS5-300 on the Cr(VI)reduction is the best by comparing the photocatalytic reduction efficiency of Cr(VI)with the catalyst.By studying the adsorption properties of N-TBBFS catalyst,the effect of reaction conditions on the treatment of Cr(VI)wastewater was explored,and the adsorption isotherm model and the apparent adsorption kinetics model were also discussed.The results show that the removal rate of 0.1 g N-TBBFS5-300 to 50 mL 20 mg/L Cr(VI)solution under the condition of pH=1.5 at room temperature can reach 97%;increasing the dosage and increasing the temperature are favorable for the adsorption of Cr(VI);the isothermal adsorption and adsorption kinetics of Cr(VI)by N-TBBFS5-300 follow the Langmuir adsorption isotherm model and pseudo second order kinetics model.By studying the photocatalytic activity of N-TBBFS catalyst,the effect of reaction conditions on the photocatalytic reduction rate of Cr(VI)was investigated,and the apparent kinetic analysis was carried out.The results show that the photocatalytic reduction rate of 30 mg N-TBBFS5-300 to Cr(VI)wastewater of 30 mL 20 mg/L can reach 96.78%under the condition of the light 5 h,pH=1.5,and 300 r/min of stirring rate;increasing the stirring rate and reducing the concentration of Cr(VI)are favorable for the photocatalytic reduction of Cr(VI);The photocatalytic reduction of Cr(VI)by N-TBBFS5-300 is a first-order reaction,and is consistent with the Langmuir-Hinshelwood(L-H)kinetic model.The reaction rate constant is k=0.5365 mg/(L·min),and the apparent adsorption constant was K=0.02199 L/mg.