Clean and safe drinking water is vital. Tragically, this quality has been degraded due to the anthropomorphic and continuous discharge of toxic and non-biodegradable organic pollutants into the aquatic environment. Among the many sources of water pollution, the textile industry has become a major problem as wastewater containing dyes is often discharged into natural water bodies. Studies have shown that a major portion (similar to 20 %) of dyes is lost during synthesis and processing operations and end up in wastewater. Due to their ubiquitous industrial use, textile dyes are categorized as pollutants of major concern, posing an ongoing threat worldwide. The discharge of dyes and/or their degradation byproducts in the aquatic environment poses serious health risks to aquatic plants, organisms, and humans, making it necessary to remove them at their source. This review article aims to present and discuss the most advanced and state-of-art technical and scientific developments in the removal and degradation of dyes from textile wastewater. This review discusses the emergence of the latest nanomaterials, current focus, and superior efficiencies of the state-of-the-art materials, with emphasis on physical and chemical approaches. By comparing frequently studied treatment methods for cost and efficiency, the future outlook provides insights into selection of treatment options, knowledge gaps, and how to improve the efficiency of applicable systems. This feasibility analysis will help readers select the most efficient treatment process from both a performance and financial perspective. While multistage hybrid technologies are worth pursuing, few technologies such as ozonation and photo-Fenton have emerged as promising independent processes. Their individual combination with filtration methods has the ability to provide an economically feasible and time-efficient solution. However, there is room for further improvement in developing or tailoring models, methods and processes that target not only dyes but also secondary factors (such as chemical oxygen demand), while remaining cost-effective and affordable for all parts of the world.

A cellulose graft copolymer (cellulose nanoresin) was synthesized by the all-aqueous functionalization of cellouronic acid with poly (vinyl benzyl trimethyl ammonium chloride) (poly(vbTMAC)). Cellulose was oxidized using the highly reported 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-mediated selective C-6 oxidation reaction. Fischer–Speier esterification of cellouronic acid was used to graft poly(vbTMAC) to the cellulosic backbone in a facile click-like mechanism. Synthesis of cellulose nanoresin was confirmed using dynamic light scattering and zeta potential measurements. Conductometric titration was used to determine the carboxylate content of cellouronic acid and the percent functionalization of the cellulose nanoresin, which was 1.69 ± 0.03 mmol/g and 61.2 ± 4

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.

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 polymerfunctionalized 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-fimctionalized 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.

This paper reports on sonochemically catalyzed atom transfer radical polymerization (SONO-ATRP) polyelectrolyte synthesis and chain-end functionalization to single-walled carbon nanotubes (SWCNT). This all aqueous process is kinetically facile without use of initiator, or reducing agents and with very low concentrations of catalyst. The process achieves high functionalization density of polymer onto the SWCNTs. These functionalized nanoscale resins (NanoResins) exhibit high performance as fast and sustainable water purification materials. SONO-ATRP of vinyl benzyl trimethyl ammonium chloride (vbTMAC) was performed in aqueous medium resulting in short polyelectrolyte strands with high atom economy and high monomer conversions (93%) at room temperature using a thin probe sonicator (144 W cm(-2), 20 kHz, for 4 h). Kinetics analysis showed first order kinetics with respect to monomer concentration in presence of or absence of sonication power. Low temperature SONO-ATRP functionalization of SWCNTs is achieved within two hours without added reducing agent while similar functionalization density using reducing agents without sonochemistry required 12 h under reflux conditions. Functionalized NanoResin membranes were tested against surrogate analyte and demonstrated high performance Thomas Model breakthrough curves with a maximum adsorption capacity of 139 +/- 1 mg g(-1) and water flux of 692 L m(-2)h(-1)bar(-1) at one atmosphere pressure. Moreover, these materials are easily regenerated and reused without loss of performance or degradation.

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.

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.