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-C 3 N 4 /TiO 2 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-C 3 N 4 /TiO 2 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 TiO 2 and g-C 3 N 4 that is attributed to the positive synergetic effect of S-scheme between g-C 3 N 4 and TiO 2 nanostructure. Under solar irradiation in PTC, g-C 3 N 4 /TiO 2 was able to degrade about 94.92 and 93.07% of binary mixture MB and RhB, respectively.