Investigating the Process of Photocatalytic Removal of Methylene Blue from Wastewater Utilizing ZnO-Mn-Ce/Biochar Nanocomposites under Visible Light

In this research, the effectiveness of ZnO-Mn-Ce/biochar as catalyst and activated by H2O2 for the removal of Methylene Blue (MB) under LED light is investigated. The nanocomposite, fabricated via a simple impregnation method, incorporates biochar to enhance the adsorption capacity and ZnO doped with Mn and Ce to raise light uptake into the visible spectrum. The physical and chemical attributes of the photocatalyst were scrutinized employing XRD, SEM, EDX, FT-IR, and BET. SEM images showed that the particles are spherical in shape and relatively uniform in size. In presence of nanoparticles, the particle density in increases as compared to pure biochar. When nanoparticles are added, the size of the particles reaches the same size. This phenomenon indicates the proper loading of particles on biochar. The results of BET confirm that adding nanoparticles to biochar result in an increase in the specific surface area, average pore size, and void volume of the catalyst. Besides, the specific surface area of pure biochar and ZnO-Mn-Ce/biochar nanoparticles is 518.34 and 636.52 m2/g, respectively. The output of the optimization showed that the optimal pH values, catalyst dosage, H2O2 dose, and dye concentration were 9, 30 mg, 20 mL, and 10 ppm, for 100 min under the LED lamp. Significantly, the highest removal percentage was 97.3%. The kinetic study illustrates the first-order equation for the photocatalytic removal of MB via ZnO-Mn-Ce/biochar nanocatalyst. ZnO-Mn-Ce/biochar photocatalyst has a high ability to remove MB and can be used as an efficient and promising photocatalyst in the advanced oxidation process to treat colored wastewater.