Enhanced performance of photocatalytic treatment of Congo red wastewater by CNTs-Ag-modified TiO2 under visible light

In order to improve the treatment efficiency of printing and dyeing wastewater, the carbon nanotubes-silver-modified-titanium dioxide (CNTs-Ag-TiO2, CAT) ternary composite was prepared by a mechanical mixing method. It was found that the morphology of the prepared CAT sample was uniformly coated with strips of CNTs, speckled Ag, and lumpy TiO2. The (002) crystal plane of CNTs, the (101) crystal plane of TiO2, and the (111) crystal plane of Ag were observed, which possessed functional groups such as Ti-OH and Ti-O-C, indicating that the prepared CAT sample had photocatalytic reaction sites. The visible light utilization of titanium dioxide can be improved. The treatment effect of different proportions of CNTs-Ag-TiO2 on Congo red wastewater was tested, and the results showed that the optimum degradation effect of Congo red wastewater was CNTs: Ag = 10:1, and the doped amount of CNTs/Ag was 15%, and the removal rate of Congo red wastewater could reach 100% within 140 min. The excellent removal effect of CAT ternary composite on Congo red wastewater provided a new idea and way for the modification of TiO2 and its composites for the potential of organic dyes degradation.

Automated summary

The carbon nanotubes-silver-modified-titanium dioxide (CNTs-Ag-TiO2, CAT) ternary composite, prepared by a mechanical mixing method, showed excellent treatment efficiency in printing and dyeing wastewater by possessing photocatalytic reaction sites and enhancing visible light utilization. The optimized ratio of CNTs: Ag and the doping amount of CNTs/Ag significantly improved the removal rate of Congo red wastewater within a short period of time.