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Recently, antibacterial nanocomposite films containing sulfur nanoparticles (SNPs) have been attracting attention in the food packaging field; however, due to the hydrophobic properties of SNPs, dispersion in hydrophilic biopolymers is nonuniform. Therefore, the functionality of SNPs is not fully utilized. For addressing this, sulfur-coated Fe3O4 hybrid nanoparticles (Fe3O4@SNP) with a core–shell structure were synthesized. Functional nanocomposite films of carrageenan were fabricated by integrating with Fe3O4, SNP, and Fe3O4@SNP nanoparticles, and their properties, including mechanical strength, UV–vis barrier, water vapor permeability (WVP), surface morphology, thermal stability, water contact angle (WCA), surface color, and antibacterial activity, were studied. The Fe3O4@SNP hybrid nanoparticles were dispersed uniformly in the carrageenan matrix. Fe3O4@SNP blocked UV light more effectively (T 280 = 1.3 ± 0.2%) than SNP (T 280 = 46.5 ± 0.0%). In addition, Fe3O4@SNP showed stronger antibacterial activity against Escherichia coli and Listeria monocytogenes than SNP. SNP showed 0.63 and 2.87 log CFU/g reduction of E. coli and L. monocytogenes, respectively, whereas Fe3O4@SNP exhibited 3.20 and 4.59 log CFU/g.

The present study is an attempt to investigate the effects of preparation and operation parameters on ideal and real selectivity of polydimethylsiloxane (PDMS) coated asymmetric polyethersulfone (PES) membranes for natural gas sweetening. Scanning electron microscopy (SEM) was used to study the effect of PES concentration and solvent type on membrane morphology. The effects of operating parameters on the performance of membranes were investigated by using binary CO 2 /CH 4 , H 2 S/CH 4 and ternary H 2 S/CO 2 /CH 4 gas mixtures. Higher concentrations of PES and a higher sequential coating number increase CO 2 /CH 4 selectivity and decrease CO 2 permeance. As a notable and interesting result, the membrane exhibits rubbery PDMS behaviour for H 2 S containing feeds and displays a glassy PES membrane for CO 2 /CH 4 mixed gas. An increase in the feed pressure decreases CO 2 and CH 4 permeance and increases CO 2 /CH 4 selectivity for CO 2 /CH 4 feed. For H 2 S/CH 4 and H 2 S/CO 2 /CH 4 mixed gas, enhancing the feed pressure results in higher CH 4 and lower CO 2 and H 2 S permeance and a declined CO 2 /CH 4 and H 2 S/CH 4 selectivity. Increasing temperature in binary CO 2 /CH 4 enhances CO 2 and CH 4 permeance and decreases CO 2 /CH 4 selectivity. Increasing the temperature increases CH 4 permeance and decreases H 2 S permeance for binary H 2 S/CH 4 mixture. For ternary mixture, increasing the temperature leads to a higher permeance for CO 2 and H 2 S and a lower CH 4 permeance. For binary CO 2 /CH 4 , a higher CO 2 concentration increases the membrane gas permeance and decreases CO 2 /CH 4 selectivity. Increasing the H 2 S concentration in the feed results in a reduction in gas pressure normalised flux of gases in ternary gas feed because of an increase in Flory-Huggins interaction parameter.