| With the continuous development of global science and technology,people’s living standards and daily needs are also constantly increasing.Among them,heavy metal pollution in water is an urgent problem to be solved.Severe cases can cause death.Excessive inhalation of sulfites in wastewater can cause severe diarrhea and chronic poisoning.so water treatment is receiving more and more attention from researchers,hoping to efficiently treat heavy metal pollutants in wastewater.In this paper,two modified materials are prepared by hydrothermal method,one is modified adsorbent,the other is modified photocatalyst,and hexavalent chromium solution and sulfite solution are used as simulated wastewater to simulate heavy metal ions in wastewater.And polluting substances,and use two kinds of simulated wastewater to explore the preparation conditions,doping ratio,reaction mechanism,and reaction conditions of the two materials,so as to select the best modified materials,and use different characterization methods to characterize the best effect The two materials are combined with experimental data to conduct an in-depth analysis of the two materials.In the study of MOFs adsorption of hexavalent chromium,UIO-66 with the best adsorption performance was prepared by hydrothermal method,and it was modified from the performance test experiments of the best doping element and the best doping ratio.15%-Fe-UIO-66 with the best performance was screened out,and its adsorption capacity could reach 38.95mg/g when processing a hexavalent chromium solution with a concentration of 50mg/L,pH 6,and a volume of 50ml,and the efficiency reached 78%.The characterization results show that the crystal form of 15%-Fe-UIO-66 is consistent with the crystal form of standard UIO-66,and the specific surface area of the modified adsorbent is increased by 279.55m~2/g,and the pore melting is increased by 0.08cm~3/g,the average pore diameter increased to 4.16nm,and the surface of the material was rough and there were many wrinkles through scanning electron microscopy,which is one of the reasons for the increase in the specific surface area of the material.In the experiment of studying titanium dioxide photocatalytic hexavalent chromium,the best modified co-doped titanium dioxide prepared by the hydrothermal method(4h)was selected through the performance test,among which the co-doped elements were S and C.The optimal doping ratio is 30%for S and 5%for C.By using the best modified titanium dioxide for photocatalytic 30 mg/L,pH 3 and 50 ml volume of hexavalent chromium solution,the efficiency reached 87%,the adsorption capacity reached 26.32mg/g,and the efficiency was about 30%higher than before modification.Characterization results show that the modified material is anatase phase,the crystal form is the same as that of standard titanium dioxide,the specific surface area has increased from 192.32m~2/g before modification to 369.39m~2/g,and the pore volume has increased from 0.26cm~3/g to 0.29cm~3/g,S and C atoms are doped into the material,the forbidden band width of the modified material is reduced,the photocatalytic activity is increased,and the light absorption capacity is enhanced.The best-modified titanium dioxide and the best-modified MOFs are combined to process a high-concentration hexavalent chromium solution.First,the best-modified MOFs are used for adsorption,then the adsorbent is filtered off,and the modified titanium dioxide is used for photocatalysis.The chromium efficiency is about 95%,which is higher than the efficiency of the two best modified materials when they are processed separately,which proves the feasibility of cooperative processing. |
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