Manish Kumar Sinha

For the in situ growth method, the reaction time is important because increasing the reaction time may make it possible for the crystallized ZIF‐8 to fully cover the GO sheets; the excess of ZIF‐8 particles reduces the aspect ratio of the GO sheet. The reaction time will significantly change the morphology, affecting the composite's ability to absorb selective gas and, in turn, affect the gas selectivity. The present work identifies the reaction time for in situ growth of ZIF‐8 nanoparticles on GO sheets. The composite was synthesized at different reaction times of 2, 4, 6, and 8 h and incorporated into the PSF matrix. The fabricated membranes were characterized by FTIR, TGA, SEM, and XRD. The novel synthesized reaction time (6 h) was identified for better enhancement of CO₂/CH₄ separation. For pure gas studies, the results investigated that the CO₂ permeability and CO₂/CH₄ selectivity were increased by 223% and 98%, respectively, compared with plain PSF membrane. In mixed gas (CO₂/CH₄) studies, the CO₂ permeability and CO₂CH₄ selectivity were increased by 349% and 854%, respectively, compared with plain PSF membrane. Hence, the in situ growth method helps synthesize MOF@GO composites in the application of gas separation.

This work discussed the fabrication of polysulfone (PSF) ultrafiltration membranes with hydrophilic behaviour by adding branched polyethyleneimine (PEI) as an additive. By directly blending the base polymer and the additive in the organic solvent, the casting solution is prepared. An asymmetric ultrafiltration membrane was fabricated by the phase inversion method. The presence of PEI was confirmed by comparing the IR spectra of the plain PSF membrane and the modified PSF membrane. A scanning electron microscope was used for the comparison of morphological changes in plain and modified membranes. The membrane was characterised with respect to bovine serum albumin (BSA) adsorption, pure water flux, permeability, compaction factor, humic acid (HA) rejection, and water uptake. The fouling resistance behaviour is prompted due to the presence of hydrophilic PEI chains in the membrane. As a result, pure water flux and flux recovery ratio increased from 28.84 to 326.54 L/m2h and from 0.526 to 0.954 L/m2hkPa for the modified membrane with respect to the plain membrane, respectively.

The membrane separation process lacks intrinsic permeation characteristics to compete with other separation technologies like adsorption, sedimentation, coagulation, skimming, and distillation. A mixed matrix membrane (MMM) is one of the strategies to improve the separation characteristics with embedded nanofillers particles. Zeolite imidazolate framework (ZIF) has a new subclass of inorganic–organic hybrid materials that are being introduced as new fillers for incorporation into the polymer matrix for various applications such as oily wastewater separation, wastewater treatment, natural gas dehydration, landfill gas upgrading, and mixed gas separation. In this experimental work, a metal-organic framework called ZIF-8 was synthesized and used as a filler for modification of MMMs and characterized with FTIR and SEM. ZIF-8 nanoparticles up to 5 wt% loading were added to PSF casting solution then the permeation characteristics of MMMs showed an improved result like the pure water flux of the modified membrane at 2.5 bar was increased up to 456.38 L/m2h. In the case of pure gas separation, at 5 wt% ZIF-8 loading in PSF, the pure gas CO2 permeability at 9 bar pressure had increased to 10.54 barrer.

Water shortage is one of the most difficult issues confronting people all over the world. Rapid urbanization and water scarcity necessitate immediate action to improve sustainable water management without jeopardizing global socioeconomic growth. Thus, conventional water treatments are implemented for the purpose of eradicating various pollutants in wastewater. Traditional water treatment methods, whether in water treatment facilities or reverse osmosis (RO) plants, have run across a number of roadblocks that have significantly hampered their performance and efficiency. Integrating the membrane process with other remediation technologies in a hybrid process is a novel technique to improve contaminant extraction efficiency for our target streams. This process is termed the hybrid membrane process (HMP). On this aspect, this paper would highlight the benefits of using the HMP compared to conventional methodologies and their applications conducted in various sectors around the world. Some case studies are also reviewed illustrating its cost analysis in comparison to conventional methodologies accentuating the merits of using HMPs.