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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.

In this research, the photocatalytic removal of Methylene Blue (MB) dye was investigated using ZSM-5@ZnO nanoflowers. Facile synthesis of ZSM-5@ZnO nanoparticles was performed using a sol-gel procedure. Moreover, crystal structure, functional groups, and morphology of the synthesized nanoparticles were confirmed by applying X-Ray Diffraction (XRD) analysis, Fourier Transform InfraRed (FT-IR), Energy Dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET), and Scanning Electron Microscope (SEM) approaches. Experiments on the initial concentration of MB, catalyst dosage, pH of the medium, light source power, amount of H2O2, and kinetic studies were carried out to achieve the maximum amount of MB removal. The highest removal rate of MB dye was achieved under optimum circumstances, i.e., dye concentration of 5 mg/L, pH of 9, 0.2 ml of H2O2, 50 mg of ZSM-5@ZnO nanocatalyst dosage, and 120 min under 50 W light-emitting diode (LED) lamp irradiation. Regarding the mentioned conditions, the maximum dye removal rate was 94.09%. The Kinetic study also expresses that the removal process follows the first-order model with the equation y=0.024x, R2=0.985, and AARD = 4.269%. Besides, the optimal time for the photocatalytic removal process is 120 min. Notably, the reusability of the nanocatalyst during 5 cycles was promising, and only 4.59% of dye removal efficiency decreased.

The increasing pollution levels, rising energy demand, and the inadequacy of conventional fuels have spurred interest in alternative sources of fossil fuel supply and demand. This problem has shifted the focus towards the examination of a promising sustainable alternative for diesel fuels. In this sense, biodiesel can be a more suitable candidate for energy, environmentally harmless, and cost-competitive approach to respond to the energy demand. The application of ultrasonic energy in biodiesel production via transesterification has been endorsed as an efficient approach that improves mass transfer factors resulting in decreased reaction times and potentially lower process expense. This study investigates the advancements in ultrasonic energy for biodiesel generation from various raw materials utilizing different catalysts. A critical assessment of the current approach is furnished, emphasizing the application of ultrasonic irradiation. Besides, in order to better understand ultrasonic energy, each ultrasonic cavitation (UC) and hydrodynamic cavitation (HC) is discussed. Regarding each approach, the fundamental concepts are discussed in detail. Generally, the present study aims at conveying a comprehensive overview of ultrasonic energy usage in transesterification reactions and furnishing an outlook on prospective developments in the technology.

The growing fuel demands and drastic restrictions of politics on greenhouse gases emissions are motivating towards bioenergy research. In this paper, the yield improvement of the produced biodiesel from canola oil using transesterification process, in attendance of ZnO nanocatalyst and ultrasound waves, was investigated. The crystal size, morphology, and particle size of the prepared nanoparticles were recognized applying X-ray diffraction (XRD), scanning electron microscopy (SEM) and transverse electron microscopy (TEM) analyses, respectively. The size of ZnO nanoparticles was 45 nm with a hexagonal-shaped structure. The response surface methodology (RSM) and the Box Behnken design (BBD) were employed to analyze the impact of the independent variables on biodiesel production yield. The reliability of the proposed model was verified by applying the analysis of variance (ANOVA) with the objective of evaluating response. Regarding the yield, satisfactory accordance was obtained between the calculated and prognosticated data from RSM, with R2= 0.9910 and R2 adj= 0.9748. The optimum reaction conditions were acquired at methanol to oil molar ratio of 11.19:1 mol: mol, ultrasound irradiation time of 31.98 min, and nanocatalyst amount of 3.17 wt.%. The optimum value for the sono-biodiesel yield was achieved equal to 90.16%. Moreover, the kinetic study exhibited that the values of activation energy and Arnius frequency factor were achieved 46.23 kJ mol-1 and 5.83× 105 min-1, respectively. Accordingly, this research indicated that ZnO nanoparticles can be utilized as a promising and efficient heterogeneous catalyst for biodiesel production.