RESUMO
In this study, a new 3D porous PVDF-foam-imprinted membrane (PPIM) for the selective separation of artemisinin (ART) was first prepared via the dopamine adhesion of pre-synthesized MIPs into the interior of the PPIM. In the PPIM, the pre-synthesized molecularly imprinted polymers (MIPs) with artesunate (ARU) as a dummy template were uniformly loaded on the interior of the membrane, avoiding the defects of recognition site encapsulation found in the conventional membrane. This membrane also exhibited excellent flux, which is beneficial in practical separation applications. The PPIM was systematically characterized via FT-IR, SEM, pore-size distribution analysis, water contact angle test, membrane flux, and mechanical performance analysis, respectively. In the static adsorption experiment, the pseudo-second-order kinetic model better fitted the rebinding data of ART. Under dynamic conditions, the ART adsorption capacity of the PPIM could be further remarkably improved by tailoring the flow rate to 3 mL min-1. In the selective separation experiment, with artemether (ARE) as the competition substrate, the selective separation ability (α) of the PPIM towards ART/artemether (ARE) reached its peak value (3.16) within only 10 min at this flow rate, which is higher than that of porous PVDF foam non-imprinted membranes (PPNM) (ca. 1.5), showing great separation efficiency in a short time. Moreover, the PPIM can be reused five times without a significant decrease in its adsorption capacities, showing good regeneration performance. This work highlights a simple strategy for constructing new MIMs with high flux and great mechanical strength to achieve the efficient selective separation of ART and ARE in practical applications.
RESUMO
The crude glycerol from biomass represents an abundant and inexpensive resource which can be utilized in producing food additives such as lactic acid. The direct transformation of bioderived glycerol to lactic acid under the catalysis of bimetallic CuPdx nanoparticles as well as monometallic Cu and Pd was investigated in hydrothermal conditions. The properties of fresh and spent bimetallic CuPdx nanoparticles were characterized with various physicochemical techniques viz. XRD, TEM, HRTEM, XPS, and AAS measurements. Catalytic activity of the prepared CuPdx nanoparticles is superior to the monometallic ones due to the alloying trend and synergistic effects. At optimal experimental conditions (100 ml of glycerol and NaOH solution, catalyst/glycerol mass ratio 2:100, 220°C, and 2.0 hr), the desired lactic acid selectivity catalyzed by the bimetallic CuPd2 , CuPd3 , and CuPd4 catalysts reached 95.3%, 91.4%, and 90.9%, respectively. PRACTICAL APPLICATIONS: Lactic acid, a widely used food additive, was traditionally produced by fermentation. However, due to the limitation such as time-consuming and complex separation procedure, interest has been attracted in developing an alternative approach toward efficient production of lactic acid. An attempt was made in present study to use the biodiesel byproduct, glycerol, and chemical conversion to high-valued lactic acid. Compared with traditional biological fermentation route, it was evidenced that glycerol selective transformation to lactic acid involves a new chemical reaction path for commodity lactic acid with a large availability and economic efficiency. This finding is significant for sustainable development of biodiesel industry and elimination of environmental issues arising from the abandoned crude glycerol.
