S-scheme heterojunction g-C3N4/TiO2 with enhanced photocatalytic activity for degradation of a binary mixture of cationic dyes using solar parabolic trough reactor

Developing photocatalytic systems by larger design to achieve degradation of dye pollutants by using solar light is highly desirable. Present work is devoted to the synthesis of step-scheme (S-scheme) g-C3N4/TiO2 heterojunction which subsequently employed for simultaneous degradation of a binary mixture of Methylene blue (MB) and Rhodamine B (RhB) solution in parabolic trough collectors (PTC) as continuous flow loop photoreactor. The as-prepared g-C3N4/TiO2 was analyzed by various techniques such as FE-SEM, EDS, XRD, FT-IR, BET, elements mapping and DRS. The composite central design (CCD) was applied to express mathematical relationships among variables such as process time, catalyst mass and initial concentrations of MB and RhB in the degradation process. The photocatalytic activity of the as-prepared composite is higher than pure TiO2 and g-C3N4 that is attributed to the positive synergetic effect of S-scheme between g-C3N4 and TiO2 nanostructure. Under solar irradiation in PTC, g-C3N4/TiO2 was able to degrade about 94.92 and 93.07% of binary mixture MB and RhB, respectively. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.

Automated summary

The study focused on the synthesis of step-scheme (S-scheme) g-C3N4/TiO2 heterojunction and expressed mathematical relationships among variables in the photocatalytic degradation process using composite central design. The results showed that the photocatalytic activity of g-C3N4/TiO2 was higher than pure TiO2 and g-C3N4, demonstrating a good degradation performance.