No abstract

Curcuminoids (Curs), oleoresins from Curcuma longa L., have known anticarcinogenic and anti-inflammatory properties, but high toxicity, poor aqueous solubility and susceptibility to degradation in body fluids are deterrents to their clinical administration. Poly(methyl methacrylate) nanoparticles (PMMA-NPs) are biocompatible and resilient and can entrap hydrophobic drugs. The present investigation is related to solubilizing Curs by incorporating them in these nanoparticles (NPs) and is related to a study comparing the anticarcinogenic effect of drug-loaded NPs with free Cur using lung cancer (A549) cell line. Freshly extracted oleoresins were post loaded in PMMA-NPs prepared using emulsion polymerization. The presence of the three components of oleoresins was confirmed by thin-layer chromatography. The size and morphology of void and loaded NPs were determined by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. The NPs were spherical with diameters of 192.66±5 nm (void) and 199.16±5 nm (loaded). Drug loading and encapsulation efficiency were 6% and 93%, respectively. From the Fourier transform infrared spectroscopy spectra, the characteristic absorption vibration of poly(methyl methacrylate) and the bands at 1,383, 1,233 and 962 cm−1 for Cur moiety were observed. Drug release up to 10 days was estimated in buffer, saline and serum. The highest release of ~55% in ~3 days was noted in buffer that exhibited the highest bioavailability. The in vitro anticancer activity of loaded drug was evaluated up to 72 hours by MTT assay using A549 cell line. Cellular uptake of dye-loaded NPs was visualized within 30 minutes of incubation. The results revealed that the dose- and time-dependent cell death in case of loaded PMMA-NPs was comparable to that of free Cur. According to the study, the drug-loaded PMMA-NPs appear to be highly suitable for effective, localized and safe chemotherapy.

A new water purification ion exchange membrane has been synthesized using an all-aqueous and sustainable process. These thin film membranes exhibit a pin hole free, mesoporous architecture that rapidly removes several classes of pervasive and persistent contaminants from water.

We have developed a novel green synthetic method to covalently graft fluorographite (FGi) nanoplatelets, with quaternary ammonium polyelectrolyte chains under mild reaction conditions in water. Radical centers on the fluorographite layers react with the radical chain end on short strands of anion-exchange resins. While fluorographite is superhydrophobic, we show that the polymer radical chain end is necessary to initiate defluorination and delamination of the FGi in neutral pH water, without any pretreatment or caustic reagents. Scanning electron microscopy of thin films shows continuous and organized stacking of ellipsoidal nanoplatelets across large defect-free areas. We show that these new materials are highly effective at removing known and emerging contaminants to below environmentally relevant concentrations. Electron microscopy, vibrational spectroscopy, elemental analysis, and thermal analysis data are presented, and they are consistent with defluorination, partial exfoliation, and graphitization during the aqueous polymer grafting reaction. A radical-initiated mechanism is proposed that is consistent with the observed defluorination and oxidation of FGi nanoplatelets. The physicochemical properties, water flux, and morphology of these thin-film assemblies are described in detail. Thin membranes of polymer-functionalized fluorographite removed 99% of perfluorooctanoic acid to below 100 parts per trillion while maintaining a very high water flux over 1100 L h–1 m–2 bar–1. Percent removal of perfluorinated alkyl substances and heavy metal oxyanions versus polyelectrolyte-functionalized fluorographite membrane areal density is reported. The methodology presented in this study is a facile approach toward developing high-performance materials for sustainable and green applications.

Nanomaterials have been extensively used in polymer nanocomposite membranes due to the inclusion of unique features that enhance water and wastewater treatment performance. Compared to the pristine membranes, the incorporation of nanomodifiers not only improves membrane performance (water permeability, salt rejection, contaminant removal, selectivity), but also the intrinsic properties (hydrophilicity, porosity, antifouling properties, antimicrobial properties, mechanical, thermal, and chemical stability) of these membranes. This review focuses on applications of different types of nanomaterials: zero-dimensional (metal/metal oxide nanoparticles), one-dimensional (carbon nanotubes), two-dimensional (graphene and associated structures), and three-dimensional (zeolites and associated frameworks) nanomaterials combined with polymers towards novel polymeric nanocomposites for water and wastewater treatment applications. This review will show that combinations of nanomaterials and polymers impart enhanced features into the pristine membrane; however, the underlying issues associated with the modification processes and environmental impact of these membranes are less obvious. This review also highlights the utility of computational methods toward understanding the structural and functional properties of the membranes. Here, we highlight the fabrication methods, advantages, challenges, environmental impact, and future scope of these advanced polymeric nanocomposite membrane based systems for water and wastewater treatment applications.

IntroductionNanotechnology, with tremendous versatility and unprecedented opportunities, has ubiquitously gained the recognition in enhancing the sustainability of membrane-based water treatment processes [1,2]. The promising synergistic effects of nano-and membrane technologies provide tangible ways to develop mixed-matrices with tunable functional features, which can make the membrane separation process more productive, energy-efficient, and environmental-friendly. Amongst the nanomaterials, the carbon nanotubes (CNTs) possess outstanding structural, mechanical and electronic properties that are exploited to develop high-performance mixed-matrix systems [3]. The importance of CNTs to the membrane scientists stems from its unique potential to result in a membrane with improved permeability [4,5] Abstract. Nanomaterials potentially minimize the inherent trade-off between productivity and selectivity of membranebased ultrafiltration (UF) process. A comparative study on the reinforcement effect of pristine carbon nanotubes (CNTs) of three different configurations, viz. single-walled (SWNT), double-walled (DWNT) and multi-walled (MWNT), and their carboxylated counterparts, onto a polysulfone (Psf) host matrix of mixed-matrix UF membranes is illustrated herein. The varying structural features of carboxylated CNTs, probed by XPS analysis, underpin the enrichment of CNTs with oxygen rich functionalities following the trend of MWNT > DWNT > SWNT. The membranes with enhanced hydrophilicity and altered electrokinetics substantiate the efficacy of facilitated reinforcement of functionalized CNTs over the pristine ones. Variations in surface topography and mechanical feature of the membranes elucidate that carboxylation influences the interfacial chemistry by enhancing the dispersion stability of MWNTs more profoundly than its configurational counterparts like SWNTs and DWNTs, and concurrently alters its distribution within the membranous matrix. The enhanced ultrafiltration performances, as achieved by twofold enhancement in solvent fluxes without compromise in the solute rejection capabilities (~89-90% toward PEG, M w : 35 kDa), confirm the potential of carboxylated CNTs in leading to development of high-performance mixed-matrix membranes.