2-methacryloyloxyethyl Trimethyl Ammonium Chloride Research Articles

Two-Level Self-Thickening Mechanism of a Novel Acid Thickener with a Hydrophobic-Associated Structure during High-Temperature Acidification Processes.

Two acid thickeners, ADMC and ADOM, were prepared by aqueous solution polymerization using acrylamide (AM) and methacryloyloxyethyl trimethyl ammonium chloride (DMC) as raw materials, with or without the introduction of octadecyl polyoxyethylene ether methacrylate (OEMA). It was characterized by FTIR, 1H NMR, and the fluorescence spectra of pyrene. The double-layer thickening mechanism of ADOM was proved by comparing the thickening and rheological properties of ADMC and ADOM tested by a six-speed rotary viscometer and a HAKKE MARSIV rheometer during the acidification process. The results showed that the synthetic product was the target product; the first stage of the self-thickening ADOM fresh acid solution during high-temperature acidification was mainly affected by Ca2+ concentration, and the second stage of self-thickening was mainly affected by temperature. The residual viscosity of the 0.8 wt% ADOM residual acid solution was 250, 201.5, and 61.3 mPa·s, respectively, after shearing at 90, 120, and 150 °C for 60 min at a shear rate of 170 s-1. The thickening acid ADOM with a hydrophobic association structure has good temperature resistance and shear resistance, which can be used for high-temperature deep-well acid fracturing. In addition, no metal crosslinking agent was introduced in the system to avoid damage to its formation, and ADOM exhibited good resistance to Ca2+, which could provide ideas for the reinjection of the acidizing flowback fluid. It also has certain advantages for environmental protection.

An antibacterial biologic patch based on bacterial cellulose for repair of infected hernias

Infection-associated complications and repair failures and antibiotic resistance have emerged as a formidable challenge in hernia repair surgery. Consequently, the development of antibiotic-free antibacterial patches for hernia repair has become an exigent clinical necessity. Herein, a GBC/Gel/LL37 biological patch (biopatch) with exceptional antibacterial properties is fabricated by grafting 2-Methacryloyloxyethyl trimethylammonium chloride (METAC), a unique quaternary ammonium salt with vinyl, onto bacterial cellulose (GBC), followed by compounding with gelatin (Gel) and LL37. The GBC/Gel/LL37 biopatch exhibits stable swelling capacity, remarkable mechanical properties, flexibility, and favorable biocompatibility. The synergistic effect of METAC and LL37 confers upon the GBC/Gel/LL37 biopatch excellent antibacterial efficacy against Staphylococcus aureus and Escherichia coli, effectively eliminating invading bacteria without the aid of exogenous antibiotics in vivo while significantly reducing local acute inflammation caused by infection. Furthermore, the practical efficacy of the GBC/Gel/LL37 biopatch is evaluated in an infected ventral hernia model, revealing that the GBC/Gel/LL37 biopatch can prevent the formation of visceral adhesions, facilitate the repair of infected ventral hernia, and effectively mitigate chronic inflammation. The prepared antibacterial GBC/Gel/LL37 biopatch is very effective in dealing with the risk of infection in hernia repair surgery and offers potential clinical opportunities for other soft injuries, exhibiting considerable clinical application prospects.

Synthesis of tragacanth gum-based programmable adhesive for wood binding applications

Synthesis of graft copolymer [2-(methacryloyloxy) ethyl]trimethylammonium chloride (MAETMAC) grafted gum tragacanth was performed using the microwave-assisted technique using potassium persulfate (KPS) as a free radical initiator. The synthesized grades were optimized by varying the monomer and the initiator concentration. The intended grafting was ascertained through standard physico-chemical characterizations. The synthesized graft copolymer was studied as a water-soluble adhesive for fabrication of single lap joint. The failure shear stress of lap joint was obtained using the Universal Testing Machine (UTM). Further, the self-separation study of the lap joints was carried out by soaking the lap-joint under water until they got self-separated. The failure shear stress and self-separation time of the adhesive in water were compared with three commercial adhesives available. The properties “self separation time” in water and “failure shear stress” were programmable at the molecular level (molecular level programming) in terms of percentage grafting.

Introducing Antibacterial Property to Silk Fabric by Chemical Grafting of [2-(methacryloyloxy)ethyl] Trimethyl Ammonium Chloride (MAETC)

Introducing Antibacterial Property to Silk Fabric by Chemical Grafting of [2-(methacryloyloxy)ethyl] Trimethyl Ammonium Chloride (MAETC)

Enhanced dewaterability of sewage sludge by grafted cationic lignin-based flocculants

Lignin-based flocculants are widely used for wastewater purification, but their application in sludge dewatering has not yet been documented. In this study, a novel cationic lignin-based flocculant named LS-g-CPA was prepared by grafting cationic polyacrylamide (CPA) synthesized from methacryloyloxy ethyltrimethyl ammonium chloride (DMC) and acrylamide (AM) onto sodium lignosulfonate (LS), and its roles and underlying mechanisms in sludge conditioning were investigated. The results showed that LS-g-CPA effectively improved the dewaterability of sludge, reducing the filtration resistance and filter cake moisture content of sludge from 0.61 ± 0.05 × 1012 m/kg to 0.14 ± 0.02 × 1012 m/kg and 85.64 ± 0.25 % to 76.84 ± 0.41 %, respectively. The dewatering performance of LS-g-CPA was positively correlated with the DMC/AM ratio. The quaternary ammonium groups brought by DMC disrupted the reticular structure of extracellular polymeric substances, exposing hydrophobic residues and releasing bound water. Nevertheless, the key to LS-g-CPA for improving sludge dewatering lies more in the amphoteric flocculant properties that enhance sludge flocculation and the octopus-type structure that provides good drainage channels. This study reveals that lignin-based flocculants are effective in improving the dewaterability of sludge, which provides direct evidence for their application in sludge dewatering.

Fabrication of pH-responsive poly(vinyl alcohol)-based microfibers crosslinked with copolymers containing benzoxaborole and carboxy groups

Water-insoluble pH-responsive poly (vinyl alcohol) (PVA)-based microfibers were prepared using terpolymer of poly ([2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC)-co-methacrylic acid (MAAc)-co-5-methacrylamido-1,2-benzoxaborole (MAAmBO)) (TP) containing a quaternary ammonium cation, as well as carboxy and benzoxaborole groups. The surface of the microfibers could be positively charged by the permanent positive charge of the METAC units owing to the presence of the quaternary ammonium cation. The MAAc units formed a covalent bond with the hydroxy group of the vinyl alcohol unit by thermal treatment at 135 °C for 24 h, and the MAAmBO units formed a dynamic covalent bond with the diol group in PVA. After thermal crosslinking for 24 h, the PVA/TP microfibers exhibited almost 100% of the residual weight after immersion in water at 80 °C for 30 min. The diameters of the dried PVA/TP_25 wt% fibers were 21.4 ± 3.9 μm, and the swelling ratio was 1.65 ± 0.16 after immersing in water for 24 h. All microfibers showed a low degree of hemolysis (<5%). The PVA/TP_25 wt% fibers were strongly dyed with anionic acid red 1 (AR1) molecules at pH 3 and with cationic methylene blue (MB) molecules at pH 12, since the balance of the surface charge depend on the solution pH. These microfibers could be bundled and twisted to improve their mechanical properties; the required fracture energy after twisting was 2.30 ± 0.91 times higher than that before twisting.

Continuous-Flow Grafting of LENFLOC™ Coagulant for Water Treatment toward Circular Economy

This study investigated the efficiency of LENFLOC™ production using a microwave-assisted continuous-flow grafting process. The study discussed the contribution of plant-based coagulants for water and wastewater treatment toward the circular economy in water treatment. Lentil waste extract was used to produce LENFLOC™ using (2-methacryloyloxyethyl) trimethyl ammonium chloride with 75 wt.% on H2O as a chain monomer and cerium ammonium nitrate (≥98%) as an initiator. The continuous flow grafting process was conducted at a constant flowrate of 60 mL/min and reaction time of 30 s. The process was optimised using RSM to obtain optimum conditions of process factors. Characterisation studies were conducted using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. A comparison study was performed using a Jar test with LENFLOC™, lentil waste extract, and a polymer as coagulants. The results obtained show that the continuous-flow grafting process was efficient with an optimum grafting percentage of 330%. The characterisation studies confirmed the grafting process. A 99% turbidity removal rate was achieved with LENFLOC™ as a coagulant with a lower dosage compared to the lentil waste extract. Furthermore, microscope imaging showed improved floc compaction when using LENFLOC™ as a coagulant. The continuous-flow grafting process has been shown to be effective; therefore, its potential for upscaling the process is possible.

A multifunctional and sustainable poly(ionic liquid)-quaternized chitosan hydrogel with thermal-triggered reversible adhesion

A quaternized chitosan (QCS)@poly(ionic liquid) (PIL) hydrogel adhesive was prepared by in-situ ultraviolet (UV)-induced copolymerization of 1-vinyl-3-butyl imidazolium bromide ([BVIm][Br]) and methacryloyloxyethyl trimethylammonium chloride (DMC) in QCS aqueous solution without using any crosslinkers, which was stably crosslinked by reversible hydrogen bonding together with ion association and exhibited excellent adhesion, plasticity, conductivity and recyclability properties. Moreover, its thermal/pH-responsive behaviors and intermolecular interaction mechanism of thermal-triggered reversible adhesion were discovered, meanwhile good biocompatibility, antibacterial properties, repeated stickiness and degradability were also proved. The results showed that the newly developed hydrogel could make various tissues, organic, inorganic or metal materials adhered tightly within 1 min; after 10 binding-peeling cycles, the adhesive strength to glass, plastic, aluminum and porcine skin still remained beyond 96 %, 98 %, 92 % and 71 % of the original, respectively. The adhesion mechanism involves ion dipole interaction, electrostatic interaction, hydrophobic interaction, coordination, cation-π interaction, H-bonding and van der Waals force. For above merits, the new tricomponent hydrogel is expected to be applied in biomedical field to achieve adjustable adhesion and on-demand peeling.

Evaluation of the nanoplastics removal by using starch-based coagulants: Roles of the chain architecture and hydrophobicity of the coagulant

Four starch-based coagulants with similar charge densities but different chain architectures and hydrophilicities were designed and fabricated. These are a linear and hydrophilic coagulant, St-CTA (Starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride); a graft and hydrophilic coagulant, CS-AM-DMC (cationic starch-graft-poly[2-methacryloyloxyethyl trimethyl ammonium chloride and acrylamide]); and two graft and partially hydrophobic coagulants, CS-AM-DML (cationic starch-graft-poly[methacrylic acid 2-(benzyldimethylaminio) ethyl chloride and acrylamide]) and CS-AM-DMR (cationic starch-graft-poly[2-(methacryloyloxy)-N,N-dimethyl-N-alkyl ammonium chloride and acrylamide]) with aromatic and n-octane groups respectively. These starch-based coagulants in conjunction with polysilicic acid were employed in a current major environmental challenge which is to efficiently remove nano-sized plastics (NPs) from water. NPs of polystyrenes, polymethyl methacrylates and polyvinylchlorides were removed from different water sources under various conditions of pH and salinity. The effects of the chain architectures and hydrophilicities of the starch-based coagulants on the NPs removal have been investigated in detail. According to experimental evidence, three graft starch-based coagulants exhibited higher NPs removal efficiencies and better flocs properties than the linear St-CTA. This was attributed to the superiority of the graft chain architecture in the graft starch-based coagulants causing higher charge neutralization efficiencies in coagulative removal of NPs. In the three graft starch-based coagulants, CS-AM-DMR and CS-AM-DML with partially hydrophobic structures were more effectively to remove three NPs than CS-AM-DMC, and produced large, compact, durable and rapidly regrown flocs, due to the synergistic effects of charge neutralization and hydrophobic association. The interaction energies between NPs and the coagulants obtained from the extended Derjaguin-Landau-Verwey-Overbeek theory further confirmed that CS-AM-DMR and CS-AM-DML could achieve faster coagulation and thus higher efficiency in NPs removal. In addition, the NPs removal efficiency increased in acidic and highly saline solutions. These results obtained are of importance in guiding the design and selection of suitable polymeric coagulants for efficiently treating target contaminants in water.

Bifunctional Polymer Brush Reactor for In Situ Synthesis of Hollow Silica-Supported Gold Nanocatalysts.

Gold nanoparticles (AuNPs) on carriers have received wide attention as catalysts as a result of their excellent stability and catalytic performance. Herein, we report the design and synthesis of hollow silica-supported gold nanocatalysts (SNPs@AuNPs) composed of highly dispersed AuNPs with approximately 4.30 nm using an in situ colloidal polyelectrolyte template strategy. The monodisperse polystyrene nanospheres accompanied by poly[(2-methacryloyloxyethyl)trimethylammonium chloride] brushes were first synthesized. Subsequently, the facile polymer-brush-engaged strategy for the synthesis of hollow SNPs@AuNPs involves in situ reduction of AuNPs, hydrolytic condensation of silica, and a chemical etching process. In combination with dynamic light scattering, transmission electron microscopy, small-angle X-ray scattering, X-ray powder diffraction, and Fourier transform infrared spectroscopy, the as-obtained polymer brushes were proven as effective versatile nanoreactors for the synthesis of AuNPs and silica nanoparticles without any catalysts. Benefiting from the structural advantages, the resultant hollow SNPs@AuNPs manifested superior catalytic activity and reusability for the reduction of p-nitrophenol by sodium borohydride in aqueous solution. With a delicate design, we believe that this synthetic strategy can be extended to fabricate multifunctional nanomaterials with diverse compositions, which would be of great interest in catalysis, energy, and many other important domains.

Molecular Bottlebrushes for Immunostimulatory CpG ODN Delivery: Relationship among Cation Density, Complex Formation Ability, and Cytotoxicity.

Artificially designed short single-stranded DNA sequences containing unmethylated CG (CpG ODNs) are agonists for toll-like receptor 9 (TLR9); thus, they have great potential as vaccine adjuvants for cancer immunotherapy and preventing infectious diseases. To deliver effectively CpG ODNs into cells bearing TLR9, nanoparticle polyion complexes of cationic polymers that are able to ingest multiple CpG ODN molecules have been developed; however, their structures and synthesized polycations are hard to control and bioincompatible, respectively. To solve these issues, we designed cationic molecular bottlebrushes (CMBs) with branches that are made from copolymers of 2-methacryloyloxyethyl phosphorylcholine and 2-methacryloyloxyethyl trimethylammonium chloride. Several instrumental methods were carried out to determine the structure of a CMB and its complex with CpG ODNs. The complexation did not change the overall shape of the original CMB, and the bound CpG ODNs were captured by the outer layer of the CMB. The moderation of cations was important to reduce toxicity and improve secretion of inflammatory cytokines.

Oligo (Poly (Ethylene Glycol) Fumarate)-Based Multicomponent Cryogels for Neural Tissue Replacement

Synthetic hydrogels provide a promising platform to produce neural tissue analogs with improved control over structural, physical, and chemical properties. In this study, oligo (poly (ethylene glycol) fumarate) (OPF)-based macroporous cryogels were developed as a potential next-generation alternative to a non-porous OPF hydrogel previously proposed as an advanced biodegradable scaffold for spinal cord repair. A series of OPF cryogel conduits in combination with PEG diacrylate and 2-(methacryloyloxy) ethyl-trimethylammonium chloride (MAETAC) cationic monomers were synthesized and characterized. The contribution of each component to viscoelastic and hydration behaviors and porous structure was identified, and concentration relationships for these properties were revealed. The rheological properties of the materials corresponded to those of neural tissues and scaffolds, according to the reviewed data. A comparative assessment of adhesion, migration, and proliferation of neuronal cells in multicomponent cryogels was carried out to optimize cell-supporting characteristics. The results show that OPF-based cryogels can be used as a tunable synthetic scaffold for neural tissue repair with advantages over their hydrogel counterparts.

Shape-Tunable Biconcave Disc-Like Polymer Particles by Swelling-Induced Phase Separation of Seeded Particles with Hydrophilic Shells.

Anisotropic shape-tunable polymer particles have gained significant attention for their wide applications, and their performances are usually strongly correlated to their shapes. In contrast to convex particles, the synthesis of highly uniform concave polymer particles remains a great challenge. Here, we present a facile and effective route to synthesize biconcave polystyrene (PS) discs by swelling-induced phase separation of hydrophilically modified PS microspheres and report an unexpected finding that even a tiny amount of hydrophilic units that were incorporated into PS microspheres can significantly change the shape of phase interfaces, resulting in the transformation of disc shapes from convex to flat to concave. This is realized by several typical hydrophilic monomers, such as sodium styrene sulfonate (NaSS), acrylic acid (AA), or (2-(methacryloyloxy)ethyl)trimethylammonium chloride (METAC). The effect of the distribution of hydrophilic units in microspheres was investigated, and the mechanism of shape tuning has been discussed. The curvatures of the bottom surfaces of discs show a strong correlation to the content of hydrophilic units. In particular, we emphasize that the shape control method is general since it does not depend on specific hydrophilic units. This research paves the way for precisely structuring polymer particle shapes, which is important for polymer particles to be used for self-assembly, diffusion, rheology, transport, filler, and many other applications.

Synthesis of fluorescent Molecularly Imprinted Polymer Nanoparticles Sensing Small Neurotransmitters with High Selectivity Using Immobilized Templates with Regulated Surface Density.

To develop nanosensors to probe neurotransmitters, we synthesized fluorescent-functionalized molecularly imprinted polymeric nanoparticles (fMIP-NPs) using monoamine neurotransmitters (serotonin and dopamine) immobilized on glass beads as templates. The size and fluorescence intensity of the fMIP-NPs synthesized with blended silane couplers increased with the presence of the target but were insensitive to the target analogs (L-tryptophan and L-dopa, respectively). However, when the template is anchored by a pure silane agent, both the fluorescence intensity and particle size of the fMIP-NPs were sensitive to the structural analog of the template. Another fMIP-NP was synthesized in the presence of poly([2-(methacryloyloxy)ethyl] trimethylammonium chloride (METMAC)-co-methacrylamide) grafted onto glass beads as a dummy template for acetylcholine. Acetylcholine increased the diameter and fluorescence intensity of the fMIP-NP, but choline had no effect. When the homopolymer of METMAC was used as a template, the fluorescence intensity and size of the resulting nanoparticles were not responsive to either acetylcholine or choline. The principle of increased fluorescence intensity due to specific interaction with the target substance is probably due to the increased distance between the fluorescent functional groups and decreased self-quenching due to the swelling caused by the specific interaction with the template. The results also indicate that MIP nanoparticles prepared by solid-phase synthesis can be used for targeting small molecules, such as the neurotransmitters addressed in this study, by adjusting the surface density of the template.

Fabrication of Printable Colorimetric Food Sensor Based on Hydrogel for Low-Concentration Detection of Ammonia

With the increasing market share of ready-to-cook foods, accurate determination of the food freshness and thus food safety has emerged as a concern. To commercialize and popularize food sensing technologies, food sensors with diverse functionalities, low cost, and facile use must be developed. This paper proposes printable sensors based on a hydrogel-containing pH indicator to detect ammonia gas. The sensors were composed of biocompatible polymers such as 2-hydroxyethyl methacrylate (HEMA) and [2-(methacryloyloxy)ethyl] trimethylammonium chloride (MAETC). The p(HEMA-MAETC) hydrogel sensor with bromothymol blue (BTB) demonstrated visible color change as a function of ammonia concentration during food spoilage. Furthermore, polyacrylonitrile (PAN) was added to improve transport speed of ammonium ions as the matrix in the sensors and optimized the viscosity to enable successful printing. The color changed within 3 min at ammonia concentration of 300 ppb and 1 ppm, respectively. The sensor exhibited reproducibility over 10 cycles and selective exposure to various gases generated during the food spoilage process. In an experiment involving pork spoilage, the color change was significant before and after exposure to ammonia gas within 8 h in ambient conditions. The proposed sensor can be integrated in bar codes and QR codes that are easily mass produced.

Enhanced flocculation of aluminum oxide particles by lignin-based flocculants in dual polymer systems

Lignin is an abundant phenolic polymer produced vastly in pulping processes that could be further valorized. In this work, anionic (AKLs) and cationic (CKLs) lignin-based polymers were made by polymerizing kraft lignin (KL) with acrylic acid (AA) or [2-(methacryloyloxy) ethyl] trimethyl-ammonium chloride (METAC), respectively. In the polymerization reactions, various molar ratios of AA or METAC to KL were applied to produce AKLs and CKLs with different characteristics. The produced AKLs and CKLs were used in single and dual systems to flocculate aluminum oxide in suspension. To assess the interaction of these lignin-based polymers with the aluminum oxide particles; the zeta potential, adsorption, and flocculation of the colloidal systems were evaluated comprehensively. The flocculation performance of the lignin-derived polymers was compared with that of the homopolymers of AA and METAC (PAA and PMETAC) and commercially used flocculants. In single polymer systems, among the anionic synthesized polymers and homopolymers, KL-A4 (an AKL) was the best flocculant for the aluminum oxide suspensions owing to its largest molecular weight (330 × 103 g/mol) and highest charge density (−4.2 mmol/g). Remarkably, when KL-A4 and KL-C4 (the CKL with the highest molecular weight and charge density) were used subsequently in a dual polymer system, a larger adsorbed mass and a more viscous adlayer were formed than those of single polymer systems on the surface of aluminum oxide particles. The synergy between KL-A4 and KL-C4 was even stronger than that between homopolymers, which led to more significant adsorption on the aluminum oxide surface and, consequently, more efficient flocculation, producing larger (22 μm) and stronger flocs, regardless of the agitation intensity used in the systems.

Preparation of acrylate-modified cationic flocculant by polymer reaction and its performance in treating oilfield-produced water

Introducing a lipophilic group into a cationic polymer flocculant can effectively improve the flocculation performance for treating oilfield-produced water. Copolymerization of acrylate and cationic monomers is the most commonly used method; however, the acrylate content in the copolymer is limited by its solubility in water. In this study, a polymer reaction method was proposed to introduce a suitable acrylate into a cationic polymer to improve flocculation performance. Acrylate was introduced into the copolymer (PDD) of methacryloyloxyethyltrimethylammonium chloride (DMC) and diallylamine (DAA) via the reaction between acrylate and the secondary amine in PDD. The effects of the acrylate type, amount of acrylate introduced, and reaction conditions on the flocculation performance of the product were investigated. The experimental results showed that the hydroxy-terminated acrylate-modified PDD exhibited considerably better performance than PDD, especially the hydroxyethyl acrylate (HEA)-modified PDD (PDD-HEA). When the dosage was 20 mg/L, the oil removal of PDD-HEA was 95.8 %, which was 1.5 times higher than that of PDD. The introduction of HEA can improve the ability of PDD to aggregate oil droplets, but it causes curling of the PDD molecular chain and weakens its bridging and flocculation ability. Therefore, a higher amount of HEA introduced does not necessarily lead to a better performance of the PDD-HEA. The most suitable modification degree of the structural units in PDD was 3.3 %. This study provides new insights into the synthesis and properties of hydrophobically modified cationic polymer flocculants and is helpful for the development of flocculants for oilfield-produced water treatment.

Antibacterial waterborne polyacrylate coated fabric with underwater superoleophobicity and underoil superhydrophobicity for continuous oil/water separation

Antibacterial superamphiphilic materials with green and facile preparation process have attracted extensive attention in oil/water separation. Herein, an antibacterial waterborne polyacrylate (AWBPA) composed of [2-(methacryloyloxy)-ethyl] trimethylammonium chloride (METAC) and basic acrylate monomers has been successfully developed using the emulsion polymerization method and water as the sole solvent. By sequentially simple dip-coating of polyethyleneimine (PEI) and AWBPA, the polyester fabric can be endowed with the superamphiphilic and antibacterial properties. By prewetting with water/oil, the modified fabric holds underwater superoleophobicity/underoil superhydrophobicity, and can be used for continuous separation of light oil/water, heavy oil/water and light oil/water/heavy oil mixtures. Importantly, these modified fabrics have high antibacterial activity (99.3 ± 0.2 %), and can maintain its underwater superoleophobicity and underoil superhydrophobicity even after immersion in corrosive solution for 15 d, 100 g sand impact and 200-cycle adhesive tape-peeling, and are suitable for practical large-scale production applications.

Cationic lignin polymers as flocculants for municipal wastewater

AbstractIn this research, two lignin‐[2‐(methacryloyloxy)ethyl]trimethylammonium chloride (METAC) polymers were generated and assessed for their efficiency in treating municipally produced wastewater. The removals of chemical oxygen demand (COD) and turbidity were 47.5% and 71.2%, respectively, for the singular flocculation system at the dosage of 40–70 mg/L. For the dual coagulation/flocculation system, the polymer with a higher charge density (AM2) achieved higher COD and turbidity removals than the polymer with a lower charge density (AM1). To achieve the same organic removal from the wastewater, the alum use could be reduced from 150 mg/L in the single alum use to 35 mg/L in the dual system when used along with 65 mg/L of AM2. In both systems, lignin‐METAC polymers exhibited better performance than the flocculant used at a local wastewater treatment plant. Lignin‐METAC polymers could be used as bio‐based flocculants for the replacement of petroleum‐based flocculants and inorganic coagulants.

Copolymer-type magnetic graphene oxide with dual-function for adsorption of variety of dyes

BackgroundTo solve the dye pollution, graphene oxide (GO) is an excellent substrate for developing novel adsorbents, meanwhile surface-initiated atom transfer radical polymerization (SI-ATRP) is a progressive modification to significantly promote density of functional groups and magnetic adsorbents can efficiently simple adsorption process. Therefore, our effort has been made to develop an ideal dye absorptive material with: (i) the high adsorption capacity, (ii) the high selectivity, (iii) the favorable regeneration and reuse and (iv) the simple and fast adsorption treatment. MethodsCationic and anionic monomers (sodium 4-styrenesulfonate, Nass and methacryloyloxyethyl trimethyl ammonium chloride, DMC) were grafted onto polydopamine coated magnetic GO (Fe3O4@GO@PDA) by SI-ATRP, obtaining copolymer brush-type Fe3O4@GO@PDA@poly(NASS-co-DMC) adsorbent with dual function of sulfonic acid and tertiary amino groups. The adsorption properties of methylene blue (MB), basic fuchsin (BF), acidic fuchsin (AF), acidic chrome blue K (AK), rhodamine B (RhB) and congo red (CR) were studied. The selectivity of adsorbents was explored in mixed AF/MB solution, and further highlighted by using it to detect of MB and AF in lake water. The recycling and stability were tested by adsorption-desorption experiments in detail. Significant findingsThe adsorption capacities of MB, BF, AF, AK, RhB and CR reached 170.3, 289.7, 330.5, 148.7, 170.4 and 230.5 mg·g−1, respectively, that was found fits well with Langmuir adsorption isotherm and pseudosecond-order kinetic model. The responsible adsorption mechanisms are dominated by electrostatic interaction, hydrogen bond interaction and π-π stacking. Moreover, the adsorption selectivity of Fe3O4@GO@PDA@poly(NASS-co-DMC) could be adjustable by the regulating the ratio of NASS to DMC, and at 4:1, 1:1 and 1:4 of NASS to DMC, adsorbent generated the different recoveries in detection of MB and AF. Furthermore, the adsorbent was recycled multiple times still remained an excellent removal efficiency and structural stability. These findings demonstrates the developed dual-function adsorbent can be applied in the treatment and detection of wastewater containing both cationic and anionic dyes.