Experimental Study On Selective Removal Of Typical Pollutants In Water By Titanium Based Catalysts

The application of nano-Ti O2 as a green environmental protection catalyst for environmental governance has attracted widespread attention from scholars at home and abroad.Studies have shown that ·OH is the main active species for the degradation of pollutants in the photocatalytic process of Ti O2.It can non-selectively oxidize most organic compounds to CO2 and H2 O,resulting in the non-selective photocatalytic degradation of Ti O2 and dealing with preferential of toxic organics.Studies have shown that the presence of SO42-in water can promote the adsorption of tetracycline on the catalyst.This study intends to use dilute sulfuric acid as an inhibitor,anhydrous ethanol as a dispersant,hydrothermal preparation of nano-Ti O2,in order to improve the adsorption properties of nano-Ti O2 material,enhance the selectivity properties of Ti O2 for removaling the typical organic substances,the main content is as follows:(1)Pure Ti O2 and dilute H2SO4 modified Ti O2(SO42-/Ti O2)were synthesized by hydrothermal method,and calcined to obtain Ti O2(500℃)and SO42-/Ti O2(500℃).The materials were characterized by XRD,SEM,BET and FT-IR.The results show that the synthesized Ti O2 is 100% anatase,and the SO42-group is successfully modified into the material,which is the main factor for the selective adsorption of the material.(2)Using typical dyes such as active yellow、basic fuchsin and methylene blue as contaminant models,and the property tests were performed on two groups of materials.The results showed that the modified SO42-/Ti O2,SO42-/Ti O2(500 ℃)materials’ adsorption capacity of active yellow significantly enhanced,and showed little difference in the adsorption of basic fuchsin and methylene blue,and had obvious selective adsorption;at the same time,The SO42-/Ti O2,SO42-/Ti O2(500℃)materials obtained after modification have stable and strong adsorption and removal property to the active yellow under the acidic and weakly alkaline(p H ≤ 10)conditions,and have certainly resistance property to acid and alkali.In the "active yellow + basic fuchsin" mixed dyes,SO42-/Ti O2,SO42-/Ti O2(500 °C)preferentially selective removal of active yellow,and there is a synergistic promoting effect on the adsorption of basic fuchsin.(3)Using tetracycline(TC),sulfamethoxazole(SM1),and sulfamethylpyrimidine(SMZ)as the contaminant model to test the Photocatalysis Degradation of Ti O2(500°C)and SO42-/Ti O2(500°C).The results showed that the selectivity coefficients of SO42-/Ti O2(500°C)to tetracycline(TC),sulfamethoxazole(SM1),and sulfamethazine(SMZ)were 4.16,5.84,and 11.38.Respectively,the sulfamethoxazole(SMZ)was preferentially removed.Overall our study showed that SO42-/Ti O2(500 °C)materials can preferentially degrade the easily degradable organic pollutants and can increase the removal rate of refractory organic pollutants,and the activity and selectivity of the material are enhanced.Our results show that SO42-modified Ti O2 materials SO42-/Ti O2 and SO42-/Ti O2(500°C)have significantly enhanced the adsorption capacity and selectivity of certain organic compounds,and still has a stable adsorption capacity under acidic and weak alkaline conditions(p H ≤ 10).It has a good application value in the field of photocatalytic wastewater treatment.