The p-diethanolaminomethylcalix[4]arene-incorporated polyacrylonitrile-based facilitated-transport-nanofiber mat for O2/N2 separation.

Separation of gases from air mixture is one of the most challenging and laborious separations due to the remarkably uniform molecular size of gas molecules. Therefore, the present study aimed to synthesize polyacrylonitrile-based nanofibers mat(NM) impregnated with p-diethanolaminomethylcalix[4]arene (PAN/p-DEAC4 NM) for the separation of two crucial gases O2 and N2. The affinity of the prepared PAN/p-DEAC4 NM for O2 was examined by optimizing the loading concentration of p-DEAC4 in the range from 5% to 20% (w/v). The results showed remarkable performance of the PAN/p-DEAC4 NM for O2/N2 separation with a superior O2/N2 selectivity of 12.75 and excellent permeance of 10.2 GPU for O2 and 0.8 GPU for N2 at 2 bar. The PAN/p-DEAC4 NM followed a facilitated transport mechanism for the separation of gases and it was revealed that the p-DEAC4 platform in the PAN NM is facilitating the transport of O2 due to its greater affinity towards O2. BET analysis revealed that the prepared NM possesses non-porous morphology with a surface area of 12.69 m2 g-1. SEM micrographs also confirmed the formation of defect-free NM. Thus, this study presents a unique perspective and direction for fabricating highly permeable nanofiber mats for O2/N2 separation.

Synthesis of an insulin intercalated graphene oxide nanogel composite: evaluation of its release profile and stability for oral delivery of insulin.

Diabetes mellitus (DM) is a disorder of glucose regulation produced due to insufficient availability of insulin. Generally, insulin is given to diabetes patients via subcutaneous injection which is a painful method to deliver this drug. In this work we have made an attempt to develop an oral drug delivery system that can efficiently deliver insulin to the small intestine. An insulin intercalated GO based nanogel composite (In@GO NgC) was fabricated for oral delivery of insulin. The in vitro release of insulin from In@GO NgC was studied in artificial gastric (pH 1.2) and intestinal (pH 7.5) fluids. The In@GO NgC produced better release in artificial intestinal fluid as compared to gastric fluid. The enzymatic degradation of released insulin was also examined and the results revealed that even after 6 h of incubation, the gel remained stable and the un-degraded insulin seemed to be sufficient for the physiological processes. The efficacy of In@GO NgC was also confirmed by comparing its release profile with non-intercalated GO NgC and nanogel (Ng) without GO. The prepared nanogels were thoroughly characterized using FTIR, SEM, EDS, DSC and DLS. The better release profile and enzymatic stability of In@GO NgC suggests that it can be utilized for oral drug delivery of insulin.

Sonochemical synthesis of Co3O4 nanoparticles deposited on GO sheets and their potential application as a nanofiller in MMMs for O2/N2 separation.

In this study we report an environmentally friendly, facile and straightforward sonochemical synthetic strategy for a Co3O4/GO nanocomposite using N,N'-bis(salicylidene)ethylenediaminocobalt(ii) as a precursor and graphene oxide sheets as an immobilization support for Co3O4 nanoparticles. The synthesis was facilitated by physical and chemical effects of cavitation bubbles. The synthesized nanocomposite was thoroughly characterized for its composition and morphology using Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS), Scanning electron microscopy (SEM), UV-visible, Raman and X-ray diffraction spectroscopy (XRD), etc. The results show Co3O4 nanoparticles of 10 nm (SD 3 nm) were prepared on well exfoliated sheets of GO. The applicability of the synthesized Co3O4/GO nanocomposite was optimized as a nanofiller for mixed matrix membranes (MMMs) comprised of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) and polyvinyl chloride. The affinity of the prepared MMMs was evaluated for the separation of O2/N2 gases by varying the concentration of nanofiller, i.e. 0.03%, 0.04%, 0.05% and 0.075% (w/v). The results display high separation performance for O2/N2 gases with excellent permeance (N2 167 GPU and O2 432 GPU at 1 bar) and O2/N2 selectivity of 2.58, when the MMMs were loaded with 0.05% (w/v) of Co3O4/GO nanocomposite.

Preparation, characterization, and binding profile of imprinted semi-IPN cryogel composite for aluminum.

Human body is greatly exposed to aluminum due to its high abundance in the environment. This nonessential metal is a threat to the patients of chronic renal disorders, as it is easily retained in their plasma and quickly accumulates in different tissues. Thus, there is great need to remove it from the aqueous environment. In this study, Al3+ imprinted semiinterpenetrating polymer network (semi-IPN)-based cryogel composite was prepared and applied for the purification of environmental and drinking water samples from aluminum. Poly (2-hydroxyethyl methacrylate) (pHEMA) discs were produced via cryogenic treatment and imprinted semi-IPN was introduced to the 3-(trimethoxysilyl) propyl acrylatemodified macroporous cryogel discs. The adsorption properties and selectivity of the aluminum (III) imprinted semi-IPN cryogel composite were studied in detail. The imprinted semi-IPN cryogel composite showed good selectivity towards aluminum (III) ions with the imprinting factor (IF) of 76.4 in the presence of competing copper (II), nickle (II), and iron (III) ions. The maximum adsorption capacity of 271 µmol g-1 was obtained for aluminum (III) at pH 7.0 within 10 min using imprinted semi-IPN cryogel composite. The good selectivity and reusability of aluminum (III)-imprinted semi-IPN cryogel composite makes this material an eligible candidate for the purification of drinking water from aluminum (III) leaving important minerals remained in the water.