Decontamination of fenitrothion from aqueous solutions using rGO/MoS2/Fe3O4 magnetic nanosorbent: synthesis, characterization and removal application

Molybdenum disulfide nanoflowers - doped sodium alginate/polyvinyl alcohol porous xerogel for methylene blue and copper ion adsorption

In order to improve the adsorption performance of MoS2, as well as to solve the problems of MoS2-powder in adsorption, which is prone to agglomeration and difficulty to be recycled, we prepared MoS2-nanoflowers(MoS2-NFs), and mixed them with sodium alginate/polyvinyl alcohol(SA/PVA) to prepare MoS2-NFs/SA/PVA xerogel(MSP) by freezing-lyophilization. Then two forms of xerogels - block-MSP(MSPB) and spherical-MSP(MSPS) were prepared, and they were used as methylene blue(MB) and Cu2+ adsorbent. It was found that MoS2-NFs were evenly dispersed inside the SA/PVA with no agglomeration, while the interior of MSPB/MSPS showed the structure of parallel-pores and radial-pores, respectively. The adsorption capacity of MSPB/MSPS on MB can reach 233 mg/g, which is five times higher than SA/PVA-gel, showing excellent synergistic-adsorption effect, and the adsorption capacity for Cu2+ reaches 271 mg/g. The adsorption mechanism indicated that the adsorption of MB by MSPB/MSPS conformed to pseudo-first-order model, with electrostatic force as the main force. And their adsorption of Cu2+ conformed to pseudo-second-order model and was dominated by Lewis acid/base soft-soft interactions. Notably, after long-term adsorption, MSPB/MSPS maintains its shape and more than 90 % of the adsorption capacity, ensuring the recovery and reuse of materials. So, MSPB/MSPS has great potential in adsorption, providing a new solution for sewage purification.

Enhanced photocatalytic performance of milkvetch-derived biochar via ZnO-Ce nanoparticle decoration for reactive blue 19 dye removal

In this research, the photocatalytic removal of reactive blue 19 (RB19) dye is investigated employing zinc oxide/cerium (ZnO@Ce) nanoparticles decorated with biochar under LED irradiation. Synthesis of ZnO@Ce nanoparticles decorated with biochar was performed utilizing the co-precipitation procedure and, then, the texture and morphology of the fabricated nanocomposite were analyzed using energy dispersive X-ray (EDX), field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and Fourier transform infrared (FTIR) spectroscopy techniques. Moreover, FE-SEM images demonstrate that ZnO-Ce nanoparticles were successfully decorated on the surface of biochar. The specific surface areas of biochar and biochar/ZnO-Ce were 519.75 and 636.52 m2/g, respectively. To achieve the maximum yield in the removal of RB19 dye, the effects of operating variables including dye concentration, LED lamp power, biochar@ZnO-Ce catalyst dose, pH and H2O2 dose were explored. Besides, the maximum percentage of RB19 dye removal was 96.47% under optimal conditions, i.e. catalyst dosage of 100 mg, H2O2 dosage of 1 mL, pH of 9, initial dye concentration of 5 ppm, LED power of 50 W, and reaction time of 140 min. Furthermore, the kinetic analysis reveals that the removal of RB19 dye follows the pseudo-first order kinetic model, with calculated values of a reaction rate constant of 0.045 min-1 and a correlation coefficient of R2 = 0.99, respectively. Moreover, the reusability and recyclability of biochar@ZnO/Ce nanocatalyst was promising over five runs, with only a 6.08% decrease in RB19 dye removal efficiency. Therefore, it can be concluded that the biochar @ZnO/Ce photocatalyst can be promisingly applied for the removal of azo dyes in aqueous solutions.

Effect of MoS2 Yolk-Shell Nanostructure on the Thiophene Separation Performance of PEG Membrane

Constructing facilitated transport based on π-complexation has been drawing more and more attention in mixed matrix membranes (MMMs) for pervaporative desulfurization. Herein, a unique molybdenum disulfide (MoS2) yolk-shell nanostructure (MYNS) was prepared and incorporated into the polyethylene glycol (PEG) matrix to fabricate MMMs for model gasoline desulfurization by PV. Moreover, the effects of MYNS content, feed sulfur concentration, and feed temperature on the performance of PEG/MYNS MMMs were evaluated. It was found that there is good interfacial compatibility between the MYNS filler and the PEG matrix, and the resultant MMMs show enhanced swelling resistance against thiophene. The PV results revealed that the as-fabricated MMMs are thiophene-selective, and their desulfurization performance in the pervaporative removal of thiophene from n-octane is remarkably evaluated due to the addition of MYNS. The MMMs display the highest sulfur enrichment factor of 4.02 with an associated permeation flux of 2587 g·m−2·h−1 with the MYNS loading of 3 wt. % when carrying out in an n-octane and thiophene (500 μg·g−1) mixture at 343 K. Furthermore, a consistent increment in the permeation flux accompanied with a continuous reduction in the enrichment factor was observed with increasing the feed sulfur concentration and feed temperature. This work may offer great potential for practical gasoline desulfurization applications.