Effect of carbon molecular sieve sizing with poly(vinyl pyrrolidone) K-15 on carbon molecular sieve–polysulfone mixed matrix membrane

Mixed matrix membranes (MMMs) comprising polysulfone (PSF) Udel^® P-1700 and 30 wt% carbon molecular sieve (CMS) particles (<25 μm) have been fabricated and characterized. CMS particles were treated in poly(vinyl pyrrolidone) kollidone 15 (PVP K-15) sizing bath solution (1–10 wt% in isopropanol) prior to embedment into the matrix solution to improve matrix–sieve interfacial adhesion. This study investigated the effects of CMS sizing with PVP K-15 on the morphology and the gas separation performance of PSF–CMS MMMs. The fabricated MMMs were characterized using TGA, DSC, FESEM, ATR-FTIR and single gas permeation test using high purity O₂ and N₂. A dramatic improvement in CMS–PSF adhesion was observed using FESEM micrographs upon incorporation of PVP K-15-sized CMS particles. ATR-FTIR results suggest the occurrence of intermolecular interaction between PVP K-15 sizing layer on the outer surface of CMS particles and PSF matrix. A substantial recovery of separation performance was achieved whereby the PSF–PVP-sized CMS MMM exhibited 1.7 times higher O₂/N₂ selectivity compared to that of unmodified MMM.     

Anticorrosive and Microbial Inhibition Performance of a Coating Loaded with Andrographis paniculata on Stainless Steel in Seawater

With the trend for green technology, the study focused on utilizing a forgotten herb to produce an eco-friendly coating. Andrographis paniculata or the kalmegh leaves extract (KLE) has been investigated for its abilities in retarding the corrosion process due to its excellent anti-oxidative and antimicrobial properties. Here, KLE was employed as a novel additive in coatings and formulations were made by varying its wt%: 0, 3, 6, 9, and 12. These were applied to stainless steel 316L immersed in seawater for up to 50 days. The samples were characterized and analyzed to measure effectiveness of inhibition of corrosion and microbial growth. The best concentration was revealed to be 6 wt% KLE; it exhibited the highest performance in improving the ionic resistance of the coating and reducing the growth of bacteria.