Ammonium Chloride Research Articles

Metal-Free Atom Transfer Radical Polymerization to Prepare Recylable Micro-Adjuvants for Dendritic Cell Vaccine.

In the development of dendritic cell (DC) vaccines, the maturation of DCs is a critical stage. Adjuvants play a pivotal role in the maturation of DCs, with a major concern being to ensure both efficacy and safety. This study introduces an innovative approach that combines high efficacy with safety through the synthesis of micro-adjuvants grafted with copolymers of 2-(methacrylamido) glucopyranose (MAG) and methacryloxyethyl trimethyl ammonium chloride (DMC). The utilization of metal-free surface-initiated atom transfer radical polymerization enables the production of safe and recyclable adjuvants. These micrometer-sized adjuvants surpass the optimal size range for cellular endocytosis, enabling the retrieval and reuse of them during the ex vivo maturation process, mitigating potential toxicity concerns associated with the endocytosis of non-metabolized nanoparticles. Additionally, the adjuvants exhibit a "micro-ligand-mediated maturation enhancement" effect for DC maturation. This effect is influenced by the shape of the particle, as evidenced by the distinct promotion effects of rod-like and spherical micro-adjuvants with comparable sizes. Furthermore, the porous structure of the adjuvants enables them to function as cargo-carrying "micro-shuttles", releasing antigens upon binding to DCs to facilitate efficient antigen delivery.

Metal‐Free Atom Transfer Radical Polymerization to Prepare Recylable Micro‐Adjuvants for Dendritic Cell Vaccine

AbstractIn the development of dendritic cell (DC) vaccines, the maturation of DCs is a critical stage. Adjuvants play a pivotal role in the maturation of DCs, with a major concern being to ensure both efficacy and safety. This study introduces an innovative approach that combines high efficacy with safety through the synthesis of micro‐adjuvants grafted with copolymers of 2‐(methacrylamido) glucopyranose (MAG) and methacryloxyethyl trimethyl ammonium chloride (DMC). The utilization of metal‐free surface‐initiated atom transfer radical polymerization enables the production of safe and recyclable adjuvants. These micrometer‐sized adjuvants surpass the optimal size range for cellular endocytosis, enabling the retrieval and reuse of them during the ex vivo maturation process, mitigating potential toxicity concerns associated with the endocytosis of non‐metabolized nanoparticles. Additionally, the adjuvants exhibit a “micro‐ligand‐mediated maturation enhancement” effect for DC maturation. This effect is influenced by the shape of the particle, as evidenced by the distinct promotion effects of rod‐like and spherical micro‐adjuvants with comparable sizes. Furthermore, the porous structure of the adjuvants enables them to function as cargo‐carrying “micro‐shuttles”, releasing antigens upon binding to DCs to facilitate efficient antigen delivery.

The different adsorption-degradation behaviors of SARS-CoV-2 by bioactive chemicals in wastewater: The suppression kinetics and their implications for wastewater-based epidemiology

Wastewater-Based Epidemiology (WBE) is widely used to monitor the progression of SARS-CoV-2 pandemic. While there is a clear correlation between the number of COVID patients in a sewershed and the viral load in the wastewater, there is notable variability across different treatment plants. In particular, some facilities consistently exhibit higher viral content per diagnosed patient, implying a potential underestimation of the number of COVID patients, while others show a low viral load per diagnosed case, indicating potential attenuation of genetic material from the sewershed. In this study, we investigated the impact of nonylphenol ethoxylate (NPHE), linear alkylbenzene sulfonic acid (LABS), bisoctyl dimethyl ammonium chloride (BDAC), and didecyldimethylammonium chloride (DDAC), the surfactants that have been commonly used as detergents, emulsifiers, wetting agents on the stability of SARS-CoV-2 in wastewater. The results showed multiple and dynamic mechanisms, including degradation and desorption, can occur simultaneously during the interaction between SARS-CoV-2 and different chemicals depending on the physicochemical properties of each chemical. Through the elucidation of the dynamic interactions, the findings from this study could help the state health organizations and scientific community to optimize the SARS-CoV-2 wastewater-based epidemiology strategies.

The improvement on calcium leaching resistance of high SCMs content cement in ammonium chloride solution using particle gradation technique

Particle gradations of Portland cement (PC), fly ash (FA), and blast furnace slag (BFS) were optimized to improve the calcium leaching resistance of blended cement with high contents (up to 70%)of supplementary cementitious materials (SCMs). The results showed that optimized blended cement showed refined initial pore volume distribution, reduced portlandite (CH) content, finer CH macrocrystals and enhanced stability of C-(A)-S-H gel. Consequently, it displayed exceptional calcium leaching resistance with reduced losses in mechanical performance, mass and pore degradation after calcium leaching. Blended cement with 30% PC (D50 = 14.46 μm), 30% FA (D50 = 10.94 μm), 20% BFS (D50 = 10.52 μm), 13% BFS (D50 = 5.31 μm) and 7% BFS (D50 = 4.71 μm), showing compressive strength retention rate of 79.05% and mass loss rate of 1.64%, was suggested as viable choice for calcium leaching resistant concrete.

Functional Characterization of an Ammonia Transporter RhBG Mutation Identified in Diabetic Kidney Disease Patients

Metabolic acidosis is a major complication of CKD (chronic kidney disease) and DKD (diabetic kidney disease). The kidney responds to metabolic acidosis by eliminating acid, primarily by producing and excreting NH4+ in the urine. Two Rh glycoproteins, RhBG and RhCG, expressed in the collecting duct are directly involved in NH3/NH4+transport. We previously determined that RhBG transports both NH4+ and NH3 across the basolateral membrane of intercalated cells. Impaired NH3/NH4+ production and/or transport may be a factor in increasing acid load and worsening kidney disease. In type 2 diabetes, net endogenous acid production is significantly elevated, and the proportion of acid excreted as NH4+ is decreased even after accounting for diet and renal function. This is significant given that the association between acidosis and faster decline in GFR is now well established. In DKD, impaired NH4+ excretion as a potential risk factor for progression of kidney disease remains poorly understood. Specifically, the genetic risk factors contributing to DKD are unclear. Hypothesis: Defined RhBG variant(s) linked to DKD cause impaired NH3/NH4+ transport that may contribute to DKD development and progression. Methods: We conducted whole-exome sequencing (WES) analysis using data from A therosclerosis R isk i n C ommunities (ARIC) study and the C hronic R enal I nsuffciency C ohort (CRIC) study. We selected DKD patients with the most rapid GFR decline and compared them with: 1) subjects without kidney disease (healthy control); 2) diabetic patients without CKD (DM control); 3) CKD patients without diabetes (CKD control). This approach will identify single nucleotide variants (SNVs) of RhBG associated with DKD. This will also determine if the detected variants contribute to the development of kidney disease per se and whether they contribute to the development of diabetes and/or fast GFR decline. To study function, we expressed RhBG variants (and wild-type RhBG) in Xenopus oocytes by microinjecting oocytes with the respective mRNA. The effect of defined SNV of RhBG on NH3/NH4+ transport was assessed from measurements of changes in intracellular pH (pHi), membrane potential (Vm), whole cell currents (I) or surface pH (pHs) induced by exposing the oocytes to bath solutions containing NH4Cl or methyl ammonium chloride (MA/MA+). Results: We identified an SNV, rs3748569 (minor allele frequency MAF > 0.05), that was significantly associated with DKD. Significance was determined compared to DM control (OR=1.38, p=0.0026) and healthy control (OR=1.26, p=0.01). This variant has also been predicted to be deleterious by 4 bioinformatic tools. Our electrophysiological measurements showed that the resultant amino acid switch, G315R, completely inhibited transport of NH3 and NH4+ (p<0.001) and the transport of MA and MA+ (p<0.0001), compared with RhBG-WT. Conclusions: WES results suggest that this naturally occurring RhBG mutation, G315R, contributes to DKD occurrence. This effect is through the development of kidney disease and less likely due to development of diabetes. It is therefore likely a general CKD risk factor. Inhibition of NH3/NH4+ transport by this mutation is a contributing factor to its deleterious effect. This work provides experimental validation of computational predictions concerning CKD and diabetes. NIH-U54 GM104940, Paul Teschan Research, NIH-R01, Carol Lavin Bernick, Tulane institutional. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

AKAP2 plays a pivotal role in renal acid-base homeostasis during metabolic acidosis

Reversible phosphorylation and dephosphorylation of kidney proteins modulate their activities and localization and play a central role in maintaining fluid and acid-base homeostasis. The proximal tubule and the intercalated cells of the nephron are main sites of acid-base balance. It was previously demonstrated that some kidney transporters involved in the pH homeostasis were regulated by the c-AMP/Protein Kinase A (PKA) signaling pathway.The A-Kinase anchoring protein 2 (AKAP2), is a scaffold protein that binds to the Protein Kinase A (PKA) allowing the phosphorylation of target proteins but is also known to interact with Protein Phosphatase 1 and consequently contributes to protein dephosphorylation. In this study, we hypothesize that AKAP2 regulates the activity and localization of renal transporters during metabolic acidosis. An inducible and nephron-specific Akap2Pax8/LC1 knockout mouse model was generated. Fluorescent immunostaining showed that AKAP2 is present in the tubules mainly at the apical plasma membrane. AKAP2 knock-out mice in normal conditions presented an acidic urine pH and polyuria compared to control mice. Ex-vivo data from micro-perfused CCDs demonstrated a higher Na+ reabsorption and K+ secretion in AKAP2 KO mice. This suggests its importance in maintaining acid-base balance even under physiological conditions. Moreover, when treated with an ammonium chloride diet, KO mice were sensitive to the acid load; showed a lower blood pH, hyperchloremia, a lower bicarbonate level and a two-fold higher blood ammonia. The sensitivity of the KO mice further supports the role of AKAP2 in acid-base homeostasis. Although we think this is due to renal acid-base transporters activity deregulation, the consideration of a potential defect in water reabsorption mechanisms contributing to acidosis is also valid. Our study provides valuable insights into the role of AKAP2 in maintaining fluid and acid-base homeostasis in the kidneys. The findings open avenues for further research into the molecular mechanisms underlying AKAP2-mediated regulation of renal transporters and its impact on acid-base balance. Swiss National Science Foundation (SNSF). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A Study on the Production of Anhydrous Neodymium Chloride through the Chlorination Reaction of Neodymium Oxide and Ammonium Chloride

The chlorination mechanism of neodymium oxide for the production of anhydrous neodymium chloride was analyzed based on the reaction temperature and reaction ratio of ammonium chloride, considering the suppression of the generation of NdOCl, an intermediate product of the reaction process. The results were obtained by distinguishing the shape of the produced NdCl3 (powder and bulk) and the setup of the chlorination equipment, reflecting its sensitivity to moisture and oxygen. The powdered form of NdCl3 produced at 400 °C and under argon gas flow was identified as NdCl3·6(H2O), while the bulk form of NdCl3 produced by melting at 760 °C after a chlorination process consisted of anhydrous NdCl3 and NdCl3∙n(H2O). The powdered NdCl3 produced in an argon gas environment with a controlled level of oxygen (below 16.05 ppm) and moisture (below 0.01 ppm) content was identified as single-phase anhydrous NdCl3 and showed the highest chlorination conversion rate of 98.65%. The addition of overstoichiometric ratios of NH4Cl in the chlorination process decreased the total amount of impurities (N, H, and O) in the NdCl3 product and increased the conversion rate of NdCl3.

Investigation of the Resistance of Some Disinfectant Active Substances in ESBL-Producing Enterobacteriaceae

In this study, a total of 200 samples, including 100 neck skin and 100 cecum samples, were collected and analyzed from various poultry slaughterhouses on different sampling days. ESBL-producing Enterobacteriaceae were isolated and ESBL production was confirmed phenotypically by combined disk diffusion and E-test gradient strips. While ESBL production was confirmed in 10 (10%) of 100 neck skin samples, no significant ESBL production could be confirmed in 100 cecal samples. The broth microdilution method of Clinical and Laboratory Standards Institute (CLSI) was used to determine the resistance profiles against benzalkonium chloride (BC), cetylpyridinium chloride (CPC), N-alkyl dimethyl benzyl ammonium chloride (ADBAC) and potassium peroxymonosulfate (PPMS) disinfectants in 10 neck skin isolates with confirmed ESBL production. In the study, it has been determined that MIC50 and MIC90 values were respectively ADBAC (8 and 16 mg/L), BC (16 and 32 mg/L), CPC (16, and 32 mg/L), PPMS (≥ 1024 mg/L). The impacts of Enterobacteriaceae strains on food safety and public health are significant; Disinfectant resistance can lead to increased transmission of antibiotic-resistant bacteria, leading to serious infections in humans that are difficult to treat. For that reason, it is of great importance to develop effective control methods, including appropriate disinfectant use, hand hygiene and appropriate isolation measures, to prevent the spread of disinfectant resistant Enterobacteriaceae strains in food production systems.

Elastic and Self-Healing Copolymer Coatings with Antimicrobial Function.

The revolutionary self-healing function for long-term and safe service processes has inspired researchers to implement them in various fields, including in the application of antimicrobial protective coatings. Despite the great advances that have been made in the field of fabricating self-healing and antimicrobial polymers, their poor transparency and the trade-off between the mechanical and self-healing properties limit the utility of the materials as transparent antimicrobial protective coatings for wearable optical and display devices. Considering the compatibility in the blending process, our group proposed a self-healing, self-cross-linkable poly{(n-butyl acrylate)-co-[N-(hydroxymethyl)acrylamide]} copolymer (AP)-based protective coating combined with two types of commercial cationic antimicrobial agents (i.e., dimethyl octadecyl (3-trimethoxysilylpropyl) ammonium chloride (DTSACL) and chlorhexidine gluconate (CHG)), leading to the fabrication of a multifunctional modified compound film of (AP/b%CHG)-grafted-a%DTSACL. The first highlight of this research is that the reactivity of the hydroxyl group in the N-(hydroxymethyl)acrylamide of the copolymer side chains under thermal conditions facilitates the "grafting to" process with the trimethoxysilane groups of DTSACL to form AP-grafted-DTSACL, yielding favorable thermal stability, improvement in hydrophobicity, and enhancement of mechanical strength. Second, we highlight that the addition of CHG can generate covalent and noncovalent interactions in a complex manner between the two biguanide groups of CHG with the AP and DTSACL via a thermal-triggered cross-linking reaction. The noncovalent interactions synergistically serve as diverse dynamic hydrogen bonds, leading to complete healing upon scratches and even showing over 80% self-healing efficiency on full-cut, while covalent bonding can effectively improve elasticity and mechanical strength. The soft nature of CHG also takes part in improving the self-healing of the copolymer. Moreover, it was discovered that the addition of CHG can enhance antimicrobial effectiveness, as demonstrated by the long-term superior antibacterial activity (100%) against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria and the antifouling function on a glass substrate and/or a silica wafer coated by the modified polymer.

Analysis of the Drag Reduction Performance and Rheological Properties of Drag-Reducing Additives.

In the practical application of hydraulic rotating machinery, it is essential to thoroughly explore drag reduction and rheological characteristics of drag-reducing additives to optimize machinery efficiency and reduce equipment consumption. This paper combines simulation and experimental approaches to investigate the drag-reduction performance and rheological properties of drag-reducing additives. Numerical simulations are initially conducted to investigate the shear-thinning properties of drag-reducing fluid and explore variations in drag-reduction rate. Turbulent phenomena characteristics are described by analyzing turbulent statistical quantities. Subsequently, the rheological behaviors of polyethylene oxide (PEO), cetyltrimethyl ammonium chloride (CTAC), and their mixed solutions under different conditions are scrutinized using a rotational rheometer. The findings indicate that the drag reduction effect amplifies as the rheological index n and characteristic time λ decrease. The numerical simulations show a maximum drag reduction rate of 20.18%. In rheological experiments, a three-stage viscosity variation is observed in single drag-reducing additives: shear thickening, shear thinning, and eventual stabilization. Composite drag-reducing additives significantly reduce the apparent viscosity at low shear rates, thereby strengthening the shear resistance of the system.

Synthesis, investigation of temperature and salt resistant polyacrylamide microspheres used for deep sealing and profile control and function strengthening mechanism

AbstractBased on the requirements of deep sealing and profile control for the excellent temperature and salt resistance on polyacrylamide microspheres, the Poly‐AM/AMPS was prepared depends on aqueous solution polymerization method to improving oil and gas recovery efficiency in low‐permeability and heterogeneous reservoirs resulted by water channeling. The key technical parameters were established through single‐factor experimental methods, and the chemical structure was studied by infrared spectrum analysis (FTIR), energy spectrum analysis, and x‐ray diffraction analysis, and then the thermal stability was investigated depends on the thermogravimetric (TG) and differential thermogravimetric (DTG) distribution curves, moreover, the particle size and distribution, microstructure, and surface morphology were further studied. As a result, the results confirmed that the molecular structure of Poly‐AM/AMPS meets the expected design, and the quality retention rate at 800°C is 17.4%, the median particle size of Poly‐AM/AMPS particles is 35.88 μm, and the particle size distribution range is about 1.94–497.8 μm. Further, the Poly‐AM/AMPS was modified by maleic anhydride, sodium styrenesulfonate, and dimethyl diallyl ammonium chloride through conventional functional strengthening and modification, modified by nano‐SiO2, GO, and S‐CaCO3 through nano‐functional strengthening and modification. Additionally, the functional strengthening and modification mechanism was studied depends on the FTIR, TG, and DTG methods.

Local incomplete combustion emissions define the PM2.5 oxidative potential in Northern India

The oxidative potential (OP) of particulate matter (PM) is a major driver of PM-associated health effects. In India, the emission sources defining PM-OP, and their local/regional nature, are yet to be established. Here, to address this gap we determine the geographical origin, sources of PM, and its OP at five Indo-Gangetic Plain sites inside and outside Delhi. Our findings reveal that although uniformly high PM concentrations are recorded across the entire region, local emission sources and formation processes dominate PM pollution. Specifically, ammonium chloride, and organic aerosols (OA) from traffic exhaust, residential heating, and oxidation of unsaturated vapors from fossil fuels are the dominant PM sources inside Delhi. Ammonium sulfate and nitrate, and secondary OA from biomass burning vapors, are produced outside Delhi. Nevertheless, PM-OP is overwhelmingly driven by OA from incomplete combustion of biomass and fossil fuels, including traffic. These findings suggest that addressing local inefficient combustion processes can effectively mitigate PM health exposure in northern India.

A novel carbon coating by electrochemical deposition in deep eutectic solvent with the assistance of ammonium chloride for stainless steel bipolar plates

In this work, pulse electrodeposition method was proposed to directly deposit amorphous carbon coating (ACC) onto 316L stainless steel substrate in choline chloride-ethylene glycol deep eutectic solvent (DES) mixed with ammonium chloride (NH4Cl) to fabricate bipolar plates. The obtained dense ACC has a thickness of ∼400 nm. Potentiodynamic and potentiostatic polarization tests demonstrated that the corrosion current density of ACC coated 316L steel was of the order of 10−7 A cm−2 in the simulated proton exchange membrane fuel cells (PEMFC) working environment, and the self-corrosion potential of the coating positively shifted by 0.4V, indicating a significant improvement on corrosion resistance of the coated steel plate due to excellent electrochemical stability of ACC. The Rockwell C indentation test showed that the as-obtained ACC was strongly bonded to the substrate and also had high in-plane strength. Further numerical simulation and comparison experiments showed that C was chemically bonded with Fe in the substrate, which was boosted by the assistance of NH4Cl. The intact and strong bonding between ACC and the substrate is highly helpful to improve corrosion resistance. The success in coating stainless steel plate with ACC by pulse electrodeposition method provides a promising alternation for coating of proton exchange membrane electrolyzer cell (PEMEC) and PEMFC metal bipolar plates.

Evaluation an anionic polyacrylamide flocculant with microblock structure in the hematite wastewater treatment: Characterization and flocculation performance

In this study, a template polymer with anionic microblock structure was successfully synthesized through ultrasonic initiated template copolymerization (USTP) by using sodium allylsulfonate (SAS) and acrylamide (AM) as monomers, poly diallyl dimethyl ammonium chloride (polyDADMAC) as template, and 2,2′-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (VA-044) as initiator. The anionic polyacrylamide (APAM-T) flocculant was characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR), and scanning electron microscopy (SEM). Furthermore, the X-ray photoelectron spectroscopy (XPS) was conducted to measure the elemental composition. The results of XPS and 1H NMR spectroscopy analysis indicated the existence of anionic microblock structure in APAM-T. Besides, the copolymerization was revealed to follow the self-assembly mechanism by analyzing the association constant (KM). The flocculation performance was evaluated by turbidity and zeta potential in the flocculation tests. The results indicated that the APAM-T with microblock structure enhanced the charge neutralization and bridging adsorption capacity, thus improving the flocculation performance. In the floc particle size distribution and fragmentation and reflocculation experiments, the floc corresponding to APAM-T had the strongest regeneration ability after fragmentation, which further confirmed the criticality of the microblock structure in enhancing the flocculation performance. Compared with existing studies, this study not only demonstrated a novel synthesis method, but also found that the microblock structure could significantly improve its treatment efficiency and effectiveness, providing a new theoretical basis and practical application path for wastewater treatment technology.

One‐pot preparation of nanoparticles via self‐assembly of sodium lignosulfonate and quaternary ammonium for controlled release of emamectin benzoate

AbstractNanoformulation was an important strategy to reduce the use of pesticides and the impacts on the environment. However, complex process and high cost hurdled the application in agriculture. In this work, sodium lignosulfonate (SL) and cetyltrimethyl ammonium chloride (CTAC) were combined into nanoparticles and utilized as carriers for emamectin benzoate (EB), using a one‐pot method at mild conditions. The structure of nanoparticle was investigated by dynamic light scattering, ζ‐potential measurement, Fourier transform infrared spectroscopy, and transmission electron microscopy, and related to the loading and release properties. The mass ratio of SL and CTAC had great impacts on the structure of nanoparticle. The release of EB from SL‐CTAC nanoparticles was pH‐triggered. The retarding efficacy was enhanced in the medium of higher pH, due to the increased interaction between the EB and carrier. The incorporation into the nanoparticles greatly increased the insecticidal toxicity of EB. The median lethal concentration, against Spodoptera litura Fabricius larvae, of typical nanoformulation was 55% and 63% of that of conventional formulation emulsifiable concentrates after feeding for 24 and 48 h, respectively. The results indicated SL‐CTAC nanoparticles were good candidates of nanovehicles with high efficiency and low‐cost, which was of great significance to prompt the nanopesticides from laboratory investigation to agricultural application.

Mitigating antimicrobial resistance, an approach to stewardship in canine urinary tract infection.

Urinary tract infection (UTI) caused by antimicrobial resistant bacteria is common in dogs leading to serious health impact in pet animal as well as on human health. Understanding the prevalent uropathogens and their drug susceptibility is essential for limiting the antimicrobial resistance through implementation of stewardship policies. In view of this, present study was envisaged to determine the prevalent bacterial uropathogens and their antibiogram from clinical cases of canine UTI. Urine samples were collected from 35 dogs presented with clinical signs of UTI and a total of 27 bacterial isolates were recovered. Among that Escherichia coli was the most predominant isolate followed by Klebsiella aerogenes, Staphylococcus aureus, Proteus mirabilis, Enterococcus sp. and Citrobacter freundii. All isolates were found resistant to one or more 1st line antibiotics recommended by consensus guidelines and 70% of total isolates showed multidrug resistance. Additionally, this study evaluated the weightage of empirical therapy as per the consensus guidelines over antimicrobial susceptibility test guided treatment. Dogs with uncomplicated UTI were selected and categorized into three different groups (n = 6). Group 1 was treated with common empirical choice amoxycillin-clavulanic acid and dogs showed susceptible to ciprofloxacin were kept in Group 2 and treated with ciprofloxacin along with urinary alkalizer disodium hydrogen citrate. Nitrofurantoin susceptible cases were kept in Group 3 and treated with a combination of nitrofurantoin and urinary acidifier ammonium chloride. Therapeutic outcome was evaluated and success rate was higher in Group 2 and 3 than Group 1 suggested that selection of antibiotics with the use of local or institutional antibiogram data is more considerate than acknowledged international guidelines in the existing situation.

Sulfur and chloride co-doped g-C3N4 in photocatalytic peroxymonosulfate activation for enhanced acetaminophen removal: Combination of experiments and DFT calculations

As a green photocatalyst with simple synthesis method, excellent electronic structure, and metal-free properties, the deficiencies of pristine graphitic carbon nitride, such as high electron transfer resistance and narrow energy band gap, inhibit its photocatalytic activity to some extent. In this paper, we synthesized a sulfur and chlorine co-doped g-C3N4 (SCl-CN) capable of efficient photocatalytic activation of peroxymonosulfate (PMS) by calcining a mixture of ammonium chloride and thiourea. By means of DFT calculation, the contribution of sulfur and chlorine to photogenic electron hole separation was discussed. The electrostatic potential of SCl-CN and the adsorption model between SCl-CN and PMS were deduced, and the activation mechanism of PMS was further analyzed. According to the calculated results, the incorporation of sulfur and chlorine tuned the electronic configuration of the material and intensified the interactions between SCl-CN and PMS. It is shown that free and non-free radicals act simultaneously in the SCl-CN/PMS/Vis system. This study provides a new idea for the study of photocatalytic activation of PMS by non-metallic co-doped carbon nitride.

Demulsification of surfactant-rich emulsion systems by using amphiphilic or positively charged magnetic nanoparticles

Emulsified oily wastewater comes from many fields, such as oil exploitation, processing, storage and transport, mechanical processing and food and catering industries, causing serious environmental pollution. Considerable part of emulsified oily wastewater was extremely stable and difficult to be treated due to the existence of high-concentration surfactants. Magnetic demulsification of oil-in-water (O/W) emulsion by using magnetic nanoparticles (MNPs) attracted more and more attentions because of its flexible and efficient process; however, the study regarding the treatment of emulsified oily wastewater containing high-concentration surfactant was still few. In this study, amphiphilic dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DOTAC)-coated MNPs (M-DOTAC) and hydrophilic but highly positively charged quaternized chitosan (QC)-coated MNPs (M-QC) were employed to treat the O/W emulsions containing various contents of anionic and nonionic surfactants. Influence of surfactant type and concentration on the demulsification performance of the two MNPs was investigated in detail. Results showed that M-DOTAC could more effectively demulsify the nonionic surfactant-stabilized emulsion mainly via hydrophobic interaction, while M-QC could more efficiently demulsify the anionic surfactant-stabilized emulsion mainly via electrostatic interaction. With increasing surfactant concentration, the MNPs were still able to completely demulsify the emulsion at a relatively higher dosage. Moreover, when the two classes of MNPs were used together, highly stable emulsion system with containing both anionic and nonionic surfactants could be completely demulsified. These results suggested the synthesized two MNPs could provide simple but powerful approach to treat different emulsified oily wastewaters with containing high-concentration surfactants.

Preparation of a Lignin-Based Cationic Flocculant and Its Application in Kaolin Suspension Treatment.

The preparation of an environmentally friendly and efficient flocculant for solid-liquid separation in industrial wastewater is highly important. In this study, a novel cationic flocculant (AL-g-PAMA) was synthesized by a thermal initiation method using alkali lignin (AL) as the main chain and acrylamide (AM) and methacrylamido propyl trimethyl ammonium chloride (MAPTAC) as the grafted side chains. The structure, thermal stability, and surface morphology of the copolymers were investigated by various characterization methods. The results indicated the successful synthesis of AL-g-PAMA. AL-g-PAMA was applied to improve solid-liquid separation in kaolin suspensions. The results showed that AL-g-PAMA had excellent flocculation-sedimentation and dewatering efficiency. When the dosage of AL-g-PAMA #5 was 600.0 g/t(s), the thickness of the compressed layer was 2.2 cm, the floc settling velocity was 24.1 cm/min, and the transmittance of the supernatant was 84.0%. The moisture content of the filter cake decreased from 55.0% to 43.4% after treatment with AL-g-PAMA #5. The results of zeta potential and focused beam reflectance measurement (FBRM) analysis indicated that bridging and electroneutralization were the main flocculation mechanisms. Therefore, this study extends the potential for using lignin as a bioflocculant and provides a feasible approach to efficiently purify high-turbidity wastewater.

Xanthan gum‐toughened hydrogel for durable strain and pressure sensors

AbstractIonic conductive hydrogels have caught much attention for serving as wearable sensors, however, most hydrogel sensors are difficult to be used for repeated sensing due to low toughness and poor self‐recovery. Here, tough and self‐recovery hydrogels are constructed by introducing xanthan gum into poly(acrylamide‐co‐trimethyl ammonium chloride) (P(Am‐DMC)) hydrogel network. Xanthan gum can bind with P(Am‐DMC) chains via hydrogen bonds and the carboxyl group from xanthan gum generates electrostatic interaction with DMC, thus improving the mechanical toughness and fatigue resistance. Furthermore, the hydrogel is highly sensitive to mechanical deformation and presents durability for repeated stretching or compression, which can be designed as a wearable sensor for human motion detection. It is anticipated that the successful design of xanthan gum‐toughened hydrogel can broaden the application range of hydrogels.