One-step hydrothermal synthesis of CeVO4/bentonite nanocomposite as a dual-functional photocatalytic adsorbent for the removal of methylene blue from aqueous solutions.

Cerium vanadate/modified bentonite (CeVO4/mbt) nanocomposite with different composition percentages was synthesized through a simple one-step hydrothermal method at 180 ℃, and then its photocatalytic activity was evaluated by decolorizing methylene blue (MB) in an aqueous solution under light exposure. In order to increase the surface area as an important parameter in photocatalytic processes, bentonite was modified by ball mill method. The structural and optical properties of the synthesized composites were determined by XRD, FT-IR, DRS, FESEM, EDS, and BET measurements. XRD and EDS results confirmed the successful synthesis of pure CeVO4. FESEM images and EDS mapping showed a proper distribution of rice-like CeVO4 nanoparticles on bentonite. The removal efficiency of MB with only 0.1 g of CeVO4/mbt nanocomposite in 15 min was about 99%, which is significant compared to neat bentonite and pure CeVO4 with efficiency of 30% and 57%. The mentioned nanocomposite followed the first-order kinetics, had a reaction rate constant equal to 0.1483 min-1, and showed acceptable stability in five consecutive cycles.

Investigation of kinetics, isotherms, thermodynamics and photocatalytic regeneration of exfoliated graphitic carbon nitride/zeolite as dye adsorbent.

A novel exfoliated graphitic carbon nitride and clinoptilolite nanocomposites (Ex.g-C3N4/CP and g-C3N4/CP with a various ratios of g-C3N4 to CP) were prepared by facile method. This study evaluates the adsorption of methylene blue (MB) on the surface of synthesized adsorbents. The as-prepared composites were characterized by XRD, FT-IR, FESEM, BET and DRS. Batch experiments were carried out under various conditions, such as the amount of adsorbent and solution pH. The optimum batch experimental conditions were found under the response surface methodology. The Ex.g-C3N4/CP presented maximum removal of MB as compared to others. The removal efficiency of the as-prepared nanocomposite was significantly elevated owing to the synergistic effects. The adsorption capacities of MB (10 ppm) on Ex.g-C3N4/CP was 54.3 mg/g. The adsorption process by both composites (g-C3N4/CP and Ex.g-C3N4/CP) showed well-fitting with the Elovich kinetic model, and Langmuir isotherm. The thermodynamic study suggested that the adsorption of MB was a spontaneous and endothermic process. The reusability of g-C3N4/CP1:2 and Ex. g-C3N4/CP in removing of MB (10 ppm, pH = 9) was studied by photocatalytic regeneration under visible irradiation for three consecutive cycles. The results obtained from the experimental analyses showed that the removal of MB was easy treatment, eco-friendly, and high yield.