Poly(vinylidene fluoride) membranes fabricated by vapor‐induced phase separation (VIPS) for the adsorption removal of VB12 from aqueous solution

Abstract

Poly(vinylidene fluoride) (PVDF) membranes without any additives were fabricated by a vapor-induced phase separation method and applied to the adsorption separation of vitamin B12 (VB12) from aqueous solution. The effects of preparation conditions including PVDF concentration in dope, vapor humidity, and exposure time on the morphologies, mechanical strength, adsorption, and permeation performances are investigated in detail. The results indicate that the PVDF membranes have a uniform spongy structure without macrovoids. The lower polymer concentration, relatively higher humidity, and longer exposure time easily leads to the formation of larger polymer nodules in the membrane matrix and lower mechanical strength of membranes. The resulted PVDF membranes exhibit superior separation efficiency for both static and dynamic adsorption for VB12. In the ultrafiltration (adsorption)-regeneration cycles, the permeation flux remains above 2500 L m −2 h −1 bar −1 and the VB12 removal ratio is above 92% after six cycles. The prepared PVDF membranes show superior adsorption capacities to other traditional adsorbents (such as activated carbons, nanoclay, etc.) for VB12 removal.

Metagenomic Evidence for Cobamide Producers Driving Prokaryotic Co-occurrence Associations and Potential Function in Wastewater Treatment Plants

“…Notably, Producers accounted for only a small portion (15.5%) of the total detected MAGs, and only 1.0% of MAGs were classified as Very-Likely-Producers that contained a complete set of cobamide biosynthesis genes, while the majority of the observed MAGs were predicted to use cobamides. These results indicated that cobamides were widely shared between strains in WWTP systems, and the majority of prokaryotes use an external source, supplied by either the biosynthesis of surrounding cohorts or the low concentration residual from effluent wastewater. , And the high demand and supply rate (≈6.3:1) of cobamides inferred the significance of cobamide production microbes in the microbial community of WWTP systems.…”

“…These results indicated that cobamides were widely shared between strains in WWTP systems, and the majority of prokaryotes use an external source, supplied by either the biosynthesis of surrounding cohorts 17 or the low concentration residual from effluent wastewater. 19,58 And the high demand and supply rate (≈6.3:1) of cobamides inferred the significance of cobamide production microbes in the microbial community of WWTP systems.…”

“…These diverse and invisible organisms form a complex ecological network of competition and cooperation that supports the organization, stability, and function of world’s largest artificial biotechnological system. , In recent years, the effect of cobamides in improving the efficiency of treating wastewater has been noticed, but due to methodological limitations, it has been difficult to understand the mechanisms behind this. A previous study has detected a number of cobamides in activated sewage sludge, yet less concentration residual from effluent wastewater raises interesting research points of investigating the cobamide producers and their roles in WWTP systems. After decades of research, including the wide application of metagenomic sequencing in exploring biological communities and function in WWTPs, − it is possible to decipher the distribution of cobamide producers and their influence on the microbial relations and potential function of WWTP systems.…”