Engineering polyamide nanofiltration membrane with bifunctional terpolymer brushes for antifouling and antimicrobial properties

In order to alleviate the organic/biological membrane fouling, we propose a difunctional nanofiltration membrane with integrating antifouling and antibacterial properties. In this work, the random terpolymer containing quaternary ammonium and zwitterionic moieties is fabricated via free radical polymerization and followed by grafting on the surface of nanofiltration membrane via coupling reaction. Surface characterization demonstrates the enhanced hydrophilicity and higher surface charge after the membrane modification. Benefiting from the co-existence of quaternary ammonium and zwitterionic moieties on the membrane surface, the terpolymer-modified membrane (i.e., TP-TFC) can not only effectively inhibit the protein and bacterial adhesion, but also possess high bacteria inhibiting efficiency. In the protein/bacterial dynamic fouling test, the water flux maintenance and flux recovery of TP-TFC membranes are among the best, which is of great significance for the long-term antibacterial properties. Results reported here shed light on a novel approach for fabricating the antifouling and antimicrobial nanofiltration membranes.</p

Engineering polyamide nanofiltration membrane with bifunctional terpolymer brushes for antifouling and antimicrobial properties

In order to alleviate the organic/biological membrane fouling, we propose a difunctional nanofiltration membrane with integrating antifouling and antibacterial properties. In this work, the random terpolymer containing quaternary ammonium and zwitterionic moieties is fabricated via free radical polymerization and followed by grafting on the surface of nanofiltration membrane via coupling reaction. Surface characterization demonstrates the enhanced hydrophilicity and higher surface charge after the membrane modification. Benefiting from the co-existence of quaternary ammonium and zwitterionic moieties on the membrane surface, the terpolymer-modified membrane (i.e., TP-TFC) can not only effectively inhibit the protein and bacterial adhesion, but also possess high bacteria inhibiting efficiency. In the protein/bacterial dynamic fouling test, the water flux maintenance and flux recovery of TP-TFC membranes are among the best, which is of great significance for the long-term antibacterial properties. Results reported here shed light on a novel approach for fabricating the antifouling and antimicrobial nanofiltration membranes.</p

Necessity Analysis of Bypass Diode for AC Module under Partial Shading Condition

To protect a photovoltaic module from the hot spot effect more efficiently, an AC (alternating current) module that contains a module-level MPPT (maximum power point tracking) has been put forward. In this paper, operation states of shadowed solar cells and relevant bypass diodes were studied through MATLAB/Simulink tools, and a commercial PV module was used to reveal the temperature change when working at different LMPP (local maximum power point). Experiment results show that bypass diode can reduce power loss for the AC module to some extent but has a limited effect on protecting the AC module from the hot spot effect. Instead, it is more likely to form a local hot spot when the bypass diode turns on, and the worst shading condition for the AC module with bypass diode is about 46.5% during work states

Necessity Analysis of Bypass Diode for AC Module under Partial Shading Condition

To protect a photovoltaic module from the hot spot effect more efficiently, an AC (alternating current) module that contains a module-level MPPT (maximum power point tracking) has been put forward. In this paper, operation states of shadowed solar cells and relevant bypass diodes were studied through MATLAB/Simulink tools, and a commercial PV module was used to reveal the temperature change when working at different LMPP (local maximum power point). Experiment results show that bypass diode can reduce power loss for the AC module to some extent but has a limited effect on protecting the AC module from the hot spot effect. Instead, it is more likely to form a local hot spot when the bypass diode turns on, and the worst shading condition for the AC module with bypass diode is about 46.5% during work states.</jats:p

Economical production of vitamin K2 using crude glycerol from the by-product of biodiesel

AbstractIndustrial waste, such as crude glycerol, was used for vitamin K2 by B. subtilis Z-15. Crude glycerol could be used instead of pure glycerin for vitamin K2 production. The combination of soybean peptone and yeast extract was more conducive to the synthesis of vitamin K2. The optimal composition of medium was obtained by response surface methodology. The results indicated that the optimal medium was as follows: 6.3% crude glycerol, 3.0% soybean peptone concentration and 5.1 g/L yeast extract. Under the optimal culture medium, vitamin K2 production was increased to 45.11 ± 0.62 mg/L. The fermentor test further proved that the use of crude glycerol affected neither the synthesis of vitamin K2 nor the growth of B. subtilis. These investigations could lay a foundation for reducing the pollution of crude glycerol, exploring a late model for vitamin K2 cleaner production.</jats:p

Bioremediation of oil contaminated soil using agricultural wastes via microbial consortium

AbstractAgricultural wastes, such as wheat bran and swine wastewater, were used for bioremediation of oil-contaminated soil. Two optimised strains that could degrade oil efficiently were selected. The result showed that the best ratio of strain A to strain B was 7:3. Swine wastewater could be a replacement for nitrogen source and process water for bioremediation. Next, the Box-Behnken design was used to optimise the culture medium, and the optimal medium was as follows: microbial dosage of 97 mL/kg, wheat bran of 158 g/kg and swine wastewater of 232 mL/kg. Under the optimal medium, the oil degradation rate reached 68.27 ± 0.71% after 40 d. The urease, catalase, and dehydrogenase activities in oil-contaminated soil all increased, and the microbe quantity increased significantly with manual composting. These investigations might lay a foundation for reducing the pollution of agricultural wastes, exploring a late model for bioremediation of oil-contaminated soil.</jats:p