Diallyldimethylammonium Chloride Research Articles

A cathodic photoelectrochemical self-powered aptasensor for ratiometric detection of cortisol based on PCN-224@graphene nanocomposites

Cathodic photoelectrochemical (PEC) sensors have garnered considerable research interest in bioanalysis for their ability to mitigate interference from photogenerated holes in concomitant reducing substances, but there remains a challenge to improve detection accuracy with rational strategies. In this study, a ratiometric assay was developed for cathodic PEC aptasensing of cortisol (COR), a stress hormone. Under visible-light exposure, porphyrin-based metal organic framework (PCN-224) and poly(diallyldimethylammonium chloride)-modified reduced graphene oxide (PrGO) composites were utilized as photoactive materials, enabling cathodic photocurrent production at 0 V. The spatially resolved dual photocathodes were combined with a COR-binding aptamer to selectively recognize the COR target, with one serving as the control. The ratio of the concentration-dependent inhibited photocurrent response (PI1) to the reference signal (PI2) from the control photocathode was employed for the sensitive COR bioassay. The proposed aptasensor revealed a broad linear range toward COR concentration from 0.4 nM to 800 nM, with a detection limit (3S/N) of 0.14 nM. The proposed sensor was successfully applied to real human serum samples, demonstrating promise in detecting disease markers in medical diagnostics.

Getting the Best out of Capillary Electrophoresis and Capillary Electrophoresis-Mass Spectrometry by Quantifying Sources of Peak Broadening for Proteins Using Polyelectrolyte Multilayer Coated Fused Silica Capillaries.

Capillary electrophoresis (CE) has emerged as a relevant technique for protein and biopharmaceutical analysis, as it combines high separation efficiency, sensitivity, and versatility. The use of capillary coatings, including successive multiple ionic-polymer layers (SMILs), reduces interactions between analytes and the capillary, further improving the CE performance. Nevertheless, separations done on SMIL coatings rarely surpass 500 × 103 plates/m. To obtain the best out of the CE, it is interesting to have a detailed look at the sources of peak dispersion. Separations of a mix of model proteins were performed on (poly(diallyldimethylammonium chloride)/poly(styrenesulfonate))2.5-coated capillaries at different electrical field strengths, leading to plate height H against migration velocity u plots that enabled a quantitative analysis of each contribution. Using this model, capillary lengths and injected volumes were systematically varied. For the first time, the contribution of sample electrophoretic heterogeneity to the total peak dispersion was deciphered for model proteins and a monoclonal antibody. Dispersion due to electromigration was seen to have an impact on plate heights in the case of triangular peaks of small molecules but not for proteins under the present conditions. UV and mass spectrometry detections were compared on the same capillary, providing valuable information on the impact of the detection type on separation efficiency. Close to 1 million plates/m were reached in the best conditions.

Effects of Dye Addition on the Rheological Properties of Aqueous Polymer Solutions.

In many commercial applications, polymer-dye interactions are frequently encountered from food to wastewater treatment, and while shear rheology has been well characterized, the extensional properties are not well known. The extensional viscosity ηE and relaxation time λE are the extensional rheological parameters that provide valuable insights into how aqueous polymers respond during deformation, and this study investigated the effect of dyes on the extensional rheology of three different aqueous polymer solutions (e.g., anionic, cationic, and neutral) paired with two different dye salts (e.g., anionic and cationic) using drop pinch-off experiments. We have found that the influence of dyes on the pinch-off dynamics is complex but generally leads to a decrease in, for example, the apparent extensional relaxation time. We have utilized the dripping-onto-substrate method to probe the uniaxial deformation of widely used polymers such as xanthan gum (XG), poly(diallyldimethylammonium chloride) (PDADMAC), and poly(ethylene oxide) (PEO) as the anionic, cationic, and neutral polymers, respectively, paired with either fluorescein (Fl) or methylene blue (MB) as the anionic and cationic dyes, respectively. Polymer-dye pairs with opposite charges (e.g., XG-MB and PDADMAC-Fl) displayed a pronounced decrease in pinch-off times, but even PEO, which is a neutral polymer, resulted in decreased pinch-off times, which was restored by the addition of NaCl. The pinch-off times for the Boger fluid (mixture of poly(ethylene glycol) and PEO), however, were surprisingly uninfluenced by dyes. These results showed that not only did the small addition of dyes strongly decrease the polymer relaxation times, but the relative importance of the dye salts on the polymer pinch-off dynamics was also different from that of pure salts such as NaCl.

Assessment of poly(diallyl dimethyl ammonium chloride) and lime for surface water treatment (pond, river, and canal water): seasonal variations and correlation analyses.

The present study deals with the assessment of different physicochemical parameters (pH, electrical conductivity (E.C.), turbidity, total dissolved solids (TDS), and dissolved oxygen) in different surface water such as pond, river, and canal water in four different seasons, viz. March, June, September, and December 2023. The research endeavors to assess the impact of a cationic polyelectrolyte, specifically poly(diallyl dimethyl ammonium chloride) (PDADMAC), utilized as a coagulation aid in conjunction with lime for water treatment. Employing a conventional jar test apparatus, turbidity removal from diverse water samples is examined. Furthermore, the samples undergo characterization utilizing X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The study also conducts correlation analyses on various parameters such as electrical conductivity (EC), pH, total dissolved solids (TDS), turbidity of raw water, polyelectrolyte dosage, and percentage of turbidity removal across different water sources. Utilizing the Statistical Package for Social Science (SPSS) software, these analyses aim to establish robust relationships among initial turbidity, temperature, percentage of turbidity removal, dosage of coagulant aid, electrical conductivity, and total dissolved solids (TDS) in pond water, river water, and canal water. A strong positive correlation could be found between the percentage of turbidity removal and the value of initial turbidity of all surface water. However, a negative correlation could be observed between the polyelectrolyte dosage and raw water's turbidity. By elucidating these correlations, the study contributes to a deeper understanding of the effectiveness of PDADMAC and lime in water treatment processes across diverse environmental conditions. This research enhances our comprehension of surface water treatment methodologies and provides valuable insights for optimizing water treatment strategies to address the challenges posed by varying water sources and seasonal fluctuations.

Identifying Root Origin of Insulating Polymer Mediated Solar Water Oxidation.

Rational construction of high-efficiency photoelectrodes with optimized carrier migration to the ideal active sites, is crucial for enhancing solar water oxidation. However, complexity in precisely modulating interface configuration and directional charge transfer pathways retards the design of robust and stable artificial photosystems. Herein, a straightforward yet effective strategy is developed for compact encapsulation of metal oxides (MOs) with an ultrathin non-conjugated polymer layer to modulate interfacial charge migration and separation. By periodically coating highly ordered TiO2 nanoarrays with oppositely charged polyelectrolyte of poly(dimethyl diallyl ammonium chloride) (PDDA), MOs/polymer composite photoanodes are readily fabricated under ambient conditions. It is verified that electrons photogenerated from the MOs substrate can be efficiently extracted by the ultrathin solid insulating PDDA layer, significantly boosting the carrier transport kinetics and enhancing charge separation of MOs, and thus triggering a remarkable enhancement in the solar water oxidation performance. The origins of the unexpected electron-withdrawing capability of such non-conjugated insulating polymer are unambiguously uncovered, and the scenario occurring at the interface of hybrid photoelectrodes is elucidated. The work would reinforce the fundamental understanding on the origins of generic charge transport capability of insulating polymer and benefit potential wide-spread utilization of insulating polymers as co-catalysts for solar energy conversion.

Microstructural Tuning of High‐Performance Bacterial Cellulose Anion Exchange Membranes via Constrained In Situ Polymerization and Double Chemical Cross‐Linking

AbstractHigh electrochemical and durability anion exchange membranes (AEMs) are a vital material for Flexible zinc‐air batteries (F‐ZAB) and AEM water electrolysis (AEMWE) to achieve green economy and environmental protection. However, the existing AEMs possess the disadvantages of a complicated preparation process, poor homogeneity, and unsatisfactory electrochemical performance. Here, a novel alkaline exchange membrane is synthesized using bacterial cellulose (BC) as the matrix, incorporating constrained in situ Poly (diallyldimethylammonium chloride) (PDDA) polymerization and double chemical cross‐linking techniques. By adjusting the microstructure, a unique long‐range order and dense internal structure to address the issue of loose bonding between PDDA and BC is established and achieve the purpose of rapid OH− conduction. The membranes exhibit excellent application properties, with excellent ionic conductivity (145.12 mS cm−1) and superb mechanical strength (73.26 MPa). Consequently, the membrane is assembled into the F‐ZAB, and the unprecedented power density of 258.7 mW cm−2 can be achieved at room temperature. Moreover, the membrane also can reach 3.0 A cm−2 at 2.3 V, indicating good prospects in the field of water electrolysis in 6 m KOH. The approach paves a new path for manufacturing AEMs for green energy and environmental applications.

Interaction of poly dimethyl diallyl ammonium chloride with sludge components: Anaerobic digestion performance and adaptive changes of anaerobic microbes

The wide utilization of poly dimethyl diallyl ammonium chloride (polyDADMAC) in industrial conditions leads to its accumulation in waste activated sludge (WAS), thereby affecting subsequent WAS treatment processes. This work investigated the interaction between polyDADMAC and WAS components from the perspective of anaerobic digestion (AD) performance and anaerobes adaptability variation. The results showed that polyDADMAC decreased the content of biodegradable organic substrates (i.e., soluble protein and carbohydrate) by binding with the functional groups and then settling to the solid phase, thus impeding the subsequent utilization. Higher concentrations of polyDADMAC prompted an initial protective response of excreting organic substrates into extracellular environment, but its toxicity to archaea was irreversible. Consequently, polyDADMAC inhibited the processes of AD and induced a 30 % reduction in methane production with 0.05 g polyDADMAC/g total suspended solid (TSS) addition. Changes in microbial community structure indicated that archaea involved in methane production (e.g., Anaerolineaceae sp. and Methanosaeta sp.) were inhibited when exposed to polyDADMAC. However, several adaptive bacteria with the ability of utilizing complex organics and participating in nitrogen cycle (e.g., Aminicenantales sp. and Ellin6067 sp.) were enriched with the above dosage. Specifically, the decreased abundance of genes relevant to methane metabolism pathway (i.e., mer and cdh) and increased abundance of genes involved in metabolism of cofactors and vitamins (e.g., nad and thi) indicated the toxicity of polyDADMAC and the irritant response of microflora. Moreover, polyDADMAC underwent degradation in AD system, resulting in a 12 % reduction in 15 days, accompanied by an increase in the -NO2 functional group. In general, this study provided a thorough understanding of the interaction between polyDADMAC and WAS components, raising concerns regarding the elimination of endogenous pollutants during AD.

Mesoporous carbon hollow spheres based sensitive SPME probes for in vivo sampling analysis of selected plant hormones in Chinese aloes

Phytohormones are a class of endogenous substances that separately or synergistically regulate the growth, development, and differentiation of plants. Accurately and efficiently detecting and monitoring the concentration of plant hormones in living plants is of significant importance. Herein, a novel mesoporous carbon hollow spheres (MCHS)-based in vivo solid phase microextraction (SPME) probe was designed for in vivo sampling of plant hormones. The designed MCHS features the advantages of high surface area, porous shells, and large hollow spaces, facilitating the dynamic adsorption and enrichment of target phytohormone. In addition, a cationic polyelectrolyte, (poly (diallyl dimethyl ammonium chloride) (PDDA), was further modified onto the MCHS to expedite the extraction process by electrostatic interaction. Utilizing the MCHS@PDDA probe in combination with HPLC-MS/MS facilitated the continuous monitoring of three plant hormones (abscisic acid (ABA), indole-3-acetic acid (IAA), and gibberellin (GA3)) in Chinese aloe. The detection limit of this method was 0.016–0.090 μg/L, the linear range was 10–1000 μg/L, and both the RSD of the single probe (n = 6) and probe-to-probe test (n = 6) were less than 7.2 %. This method had excellent accuracy and good reproducibility comparable to the traditional sample pretreatment method. Ultimately, this established in-vivo SPME method was successfully adopted to quantify three selected plant hormones in living Chinese Aloes, providing a new method for the long-term monitoring of endogenous active substances in living system.

Novel poly(2-ethyl-2-oxazoline) and poly(diallyldimethylammonium chloride) polymer functionalized montmorillonite: Physicochemical aspects and near-IR study of hydration properties

The novel functionalized montmorillonites (Mts) with non-ionic poly(2-ethyl-2-oxazoline) (PEtOx) and cationic poly(diallyldimethylammonium) (PDDA) were created via an intercalation method with different loading ratio of both polymers. A comprehensive investigation into their physicochemical properties was conducted using Carbon analysis (CA), Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), Simultaneous thermal analysis (TGA/DSC) and BET-N2 adsorption analysis. The impact of hydration on PEtOx-Mts and PDDA-Mts was assessed through gravimetric analysis and near-infrared spectroscopy (NIR) spectroscopy. PXRD analysis revealed a significant increase in 001 diffraction of PDDA-Mt corresponding to a PDDA interlayer with a basal spacing ranging from 1.47 to 1.49 nm. Conversely, the basal spacing exceeding 2 nm for PEtOx suggested, that the PEtOx polymer was intercalated in a larger amount and packed in a less compact manner compared to PDDA. After modification of Na-Mt with PEtOx polymer, FTIR spectroscopy confirmed the presence of the carbonyl CO group (3265 and 1641 cm-1) and the stretching (2982, 2942 and 2883 cm-1) and bending (1480–1200 cm-1) vibrations of the CH2 and CH3 groups. The vibrations of CH groups were further verified following PDDA modification. NIR spectroscopy also confirmed the vibrational bands attributed to both modifiers after intercalation of PEtOx and PDDA. The results of BET-N2 adsorption revealed a significant decrease in the specific surface area (SSA) after intercalation with a non-ionic PEtOx polymer. On the contrary, in the case of saturation of Na-Mt with polycation PDDA, SSA increased slightly in two instances. TGA analysis confirmed greater weight loss for PEtOx-Mts compared to PDDA-Mts. Derivative thermogravimetry (DTG) revealed the release of physisorbed bound water around 100 °C, decomposition of the organic phase within the 250–550 °C range and dehydroxylation of OH groups around 550–800 °C in both cases. The results obtained from the gravimetry and NIR analysis indicated a greater hydrophobic nature for PEtOx-Mts compared to PDDA-Mts. These findings hold substantial potential for enhancing the properties of novel organo-montmorillonites, thereby facilitating their application as adsorbents for pollutants, surface coatings, biodegradable materials, fillers in polymer nanocomposites, drug carriers, anticancer agents and various other significant applications.

Poly(dimethyldiallylammonium chloride)-modified magnetic bentonite for removal of polystyrene nanoplastics

Nanoplastics (NPs) can contaminate water sources and living organisms, posing significant challenges for removal due to their small size and complex surface properties. There is a need to develop efficient technologies for the removal of NPs. In this study, bentonite was magnetically modified and loaded with Poly(dimethyldiallylammonium chloride) (PDMDAC) to enhance the adsorption for NPs, and improve separation and recovery efficiency. The synthesized PDMDAC-modified magnetic bentonite (PDMMB) had a high specific surface area of 49.386 m2/g and a maximum adsorption capacity of 250.50 mg/g for polystyrene nanoplastics (PS-NPs). The incorporation of PDMDAC increased the surface charge of magnetic bentonite from −39.50 mV to +37.7 mV, generating strong electrostatic attraction to the negatively charged PS-NPs (-64.3 mV). The PDMMB exhibited a saturation magnetization of 17.619 emu/g and an S-type hysteresis curve, indicating strong superparamagnetism that facilitating magnetic separation and recovery. Characterization analysis revealed that the adsorption was driven by electrostatic attraction and the Fe-O functional group. Kinetics and adsorption model analyses indicated that the adsorption mechanism involved electrostatic attraction, complexation, and single/multilayer adsorption, the adsorption process was exothermic and thermodynamically favorable. The adsorption rate remained at 86.41 % after 5 adsorption-desorption cycles. PDMMB exhibited high removal efficiency over a wide range of pH (3−10), ionic strength (0.01–0.5 mol/L), and in the presence of various anion types, indicating its potential for flexible application. The high efficiency, easy operation and excellent regeneration of PDMMB demonstrate its potential for effective removal of NPs from wastewater.

Electroplating of zinc onto polyelectrolyte complex membranes as anode for aqueous zinc-ion batteries

Conventionally, the anode of a primary Aqueous zinc-ion batteries (ZIBs) is metallic and rigid, which made it difficult to integrate into flexible designs. In this research, a composite polyelectrolyte complex (PEC) with cationic poly(diallyldimethylammonium chloride), anionic poly(sodium-4-styrenesulfonate) and carbon black (CB) as conductive filler (PEC-CB) was developed as an anode substrate for zinc deposition via electroplating technique. The Zinc-electroplated PEC-CB (Zn-PEC-CB) anode was characterized using electron microscopy and X-Ray diffraction analysis to verify the successful zinc coating. The Zn-PEC-CB was then assembled with PEC-CB-MnO cathodes in an ZIB setup. The results demonstrated the potential of PEC-based electrodes as a promising alternative to conventional materials in ZIBs, encouraging further exploration in energy storage applications.

Nest-shaped hollow-encapsulated Pd catalyst enhances the catalytic performance of hydrogen peroxide directly synthesizing from hydrogen and oxygen

A well-defined structural morphology can significantly construct a special catalytic micro-reaction environment to enhance the catalytic performance of Pd catalyst in the direct synthesis of hydrogen peroxide from hydrogen and oxygen (DSHP). In this study, SiO2 was used as a rigid template, PdCl2 as the Pd precursor, and dopamine hydrochloride (DA) as the carbon and nitrogen source to synthesize a nest-shaped hollow-encapsulated Pd catalyst named PdMulti@ONHCS. This catalyst was successfully constructed via high-temperature pyrolysis of poly dimethyl diallyl ammonium chloride (PDDA), which generated a blasting effect crucial for this formation. Characterization analysis, catalytic performance evaluation experiment, and molecular dynamics simulation were conducted to explore the structure-performance relationship of PdMulti@ONHCS catalyst in DSHP. Both experimental and simulation results consistently showed that the nest-shaped hollow structure of PdMulti@ONHCS catalyst created a distinctive catalytic microreactor environment with a spatial mass transfer constraint, which was not only conducive to adsorption and enrichment of H2 and O2 at Pd active sites to produce H2O2. In addition, the generated H2O2 can be desorbed from Pd active sites in time and rapidly diffused into the reaction solution, effectively inhibiting the dissociation of species containing OO bonds on the Pd surface, resulting in severe hydrogenation and decomposition side reactions, and improving H2O2 productivity and selectivity.

Fabrication of a Microfluidic-Based Device Coated with Polyelectrolyte-Capped Titanium Dioxide to Couple High-Performance Liquid Chromatography with Inductively Coupled Plasma Mass Spectrometry for Mercury Speciation.

Mercury (Hg) is a toxic element which impacts on biological systems and ecosystems. Because the toxicity of Hg species is highly dependent on their concentration levels and chemical forms, the sensitive identification of the chemical forms of Hg-i.e., Hg speciation-is of major significance in providing meaningful information about the sources of Hg exposure. In this study, a microfluidic-based device made of high-clarity poly(methyl methacrylate) (PMMA) was fabricated. Then, titanium dioxide nanoparticles (nano-TiO2s) were attached to the treated channel's interior with the aid of poly(diallyldimethylammonium chloride) (PDADMAC). After coupling the nano-TiO2-coated microfluidic-based photocatalyst-assisted reduction device (the nano-TiO2-coated microfluidic-based PCARD) with high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS), a selective and sensitive, hyphenated system for Hg speciation was established. Validation procedures demonstrated that the method could be satisfactorily applied to the determination of mercury ions (Hg2+) and methylmercury ions (CH3Hg+) in both human urine and water samples. Remarkably, the zeta potential measured clearly indicated that the PDADMAC-capped nano-TiO2s with a predominance of positive charges indeed provided a steady force for firm attachment to the negatively charged device channel. The cause of the durability of the nano-TiO2-coated microfluidic-based PCARD was clarified thus.

Impact of Magnetic Graphene Nanofluidic Electrolytes for I3 -/I - in Zinc/Iodide Redox Flow Batteries

Redox flow batteries (RFBs) stand out as a highly promising technology to tackle the growing challenges of intermittent energy supply, known for their extended cycle life, low environmental impact, scalability, and design flexibility1 , 2. Among various RFBs, aqueous zinc-iodide redox flow batteries (ZIRFBs), have been gaining increasing attention, due to their low material costs, high solubility (ZnI2 ~ 7M), rapid kinetics, and impressive theoretical energy density (322 Wh/L)3 , 4. However, the redox reactions of I3 -/I- on the graphite felt cathode in ZIRFBs exhibit poor reversibility and electro-activity compared to the Zn/Zn2+ pair at the anode5. This discrepancy results in significant electrode polarization resistance, a major hindrance to achieving high energy efficiency and a primary obstacle to commercialize large-scale ZIRFBs. To address this issue, researchers typically enhance the cathode’s electrochemical activity or conductivity to promote the I3 -/I- reaction, thereby reducing polarization resistance, by modifying the cathode with materials such as graphene quantum dots6, metal-organic frameworks5, and conductive polymers7.Unlike electrode modifications, electrolyte nanofluids have been relatively underexplored in the RFBs field, despite several studies on carbon-based nanofluids in all vanadium RFBs and polysulfide/iodide RFBs. These nanofluidic electrolytes have demonstrated superior conductivity and higher surface area compared to carbon felt, thereby enhancing battery performance. In this study, a magnetic graphene composite was developed using a self-assembly method facilitated by electrostatic force. The graphene was prepared by electrochemical exfoliation of graphite, modified with poly(diallyldimethylammonium chloride) (PDDA) to provide a positively-charged.Material characterization with X-Ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) confirmed the successful synthesis of the composite. Flow cell experiments with a ZIRFB using a 3M solution revealed a notable improvement in the charge-discharge energy efficiency upon the addition of 0.3 mg/ml PDDA-graphene, from 72% to 82% at a current density of 30 mA/cm2, and from 47% to 60% at a current density of 70 mA/cm2. Performance improvements were also observed compared to unmodified graphene.This magnetic nanofluid holds promise for the easy separation of nanoparticles and electrolytes by a magnetic field, enabling the recovery and reuse of the nanoparticles. To endow nanoparticles with magnetism for cost-effective recovery, we further modified the PDDA-graphene with magnetite, using electrostatic self-assembly. The mass ratio of graphene to magnetite in the composite had a significant impact on the ZIRFB flow cell performance. At a mass ratio of 4:1, the nanofluid enhanced ZIRFB energy efficiency by 7.3% and 9.7% at current densities of 30 and 70 mA/cm2, respectively. Conversely, when the mass ratio was 1:1, adverse effects on battery performance were observed. In addition to the charge-discharge energy efficiency, the battery performance was also evaluated using polarization to determine the maximum power density, and electrochemical impedance spectroscope (EIS). Vinco, J. H., Domingos, A. E. E. da C., Espinosa, D. C. R., Tenório, J. A. S. & Baltazar, M. dos P. G. Unfolding the Vanadium Redox Flow Batteries: An indeep perspective on its components and current operation challenges. J. Energy Storage 43, 103180 (2021).Lourenssen, K., Williams, J., Ahmadpour, F., Clemmer, R. & Tasnim, S. Vanadium redox flow batteries: A comprehensive review. J. Energy Storage 25, (2019).Yang, Y., Liang, S. & Zhou, J. Progress and prospect of the zinc–iodine battery. Curr. Opin. Electrochem. 30, 100761 (2021).Khor, A. et al. Review of zinc-based hybrid flow batteries: From fundamentals to applications. Mater. Today Energy 8, 80–108 (2018).Li, B. et al. Metal-Organic Frameworks as Highly Active Electrocatalysts for High-Energy Density, Aqueous Zinc-Polyiodide Redox Flow Batteries. Nano Lett. 16, 4335–4340 (2016).Liu, Y. et al. Stable static zinc-iodine redox battery constructed with graphene quantum dots coated graphite felt. J. Power Sources 520, 230861 (2022).Yang, J., Song, Y., Liu, Q. & Tang, A. High-capacity zinc-iodine flow batteries enabled by a polymer-polyiodide complex cathode. J. Mater. Chem. A 9, 16093–16098 (2021).

Plasma-Chemical Modification of Polyethylene Surface for Copolymerization with Diallyldimethylammonium Chloride

Plasma-Chemical Modification of Polyethylene Surface for Copolymerization with Diallyldimethylammonium Chloride

PH controllably induced PPTA/PEMs composite nanofiltration membranes for long-term acid-resistant separation

In this study, we deposited polyelectrolyte multilayers (PEMs) on Poly (p-phenylene terephthamide) (PPTA) ultrafiltration (UF) substrates with strong polyelectrolytes (PEs): polystyrene sulfonic acid (PSS) and poly (diallyldimethylammonium chloride) (PDADMAC). The growth pattern of PEMs was shifted from linear to exponential by changing substrate potential, which was attributed to synergism and antagonism of dispersion of PEs on hydrophilic substrates and electrostatic interaction between PEs and substrates. Eventually, PEMs of layer-dominated and pore-dominated regimes were successfully obtained. We focused on the transition from the pore-dominated to the layer-dominated regime of PEMs. The PEMs nanofiltration (NF) membranes in this situation showed a better separation performance due to the together work of the interface and in-pore energy barriers. The retention rate of Na2SO4 and MgSO4 was 98 % and 91 %. The eosin Y retention rate was 99.9 % and only declined 2 % after 100 h. The hindered deposition of pore-dominated regimes led to denser and thinner layers, which achieved long-term acid resistance. It maintained a stable salt retention after 185 h cross-filtration of 0.1 M H2SO4 feed solution. The performance of PEMs NF membrane was improved from a new perspective, and excellent acid-resistant nanofiltration membranes were obtained, which are expected to be used to treat industrial acidic wastewater.

Enhanced Coagulation for Algae Removal Using Composite Al-Based Coagulants: Collaborative Optimization Mechanism of Aluminum Morphology

The main purpose of this paper was to reveal the effect of aluminum (Al)-based coagulants on enhanced coagulation for the removal of algae and the synergistic optimization mechanism among different Al species. The formation, breakage, and regrowth processes of algal coagulation flocs formed by a series of monomeric Al-based coagulants (Al2(SO4)3, Al13, and Al30), Al13/Al30 composite coagulant and poly(diallyldimethylammonium chloride)/Al13 (PDADMAC/Al13) composite coagulant were studied. Results indicated that Al13 mainly employed a charge neutralization mechanism, which was conducive to the destabilization of algae and the regeneration of flocs, while Al30 mainly employed a sweep flocculation mechanism, which was conducive to the formation of algae and the strength of flocs. Meanwhile, the charge neutralization was the main mechanism during the algae coagulation process because it could effectively remove the soluble microbial products (SMP) component in the extracellular organic matter (EOM). Therefore, Al13 could achieve a higher coagulation performance than other monomeric Al-based coagulants. The Al13/Al30 composite coagulant could make up for the deficiency of the sweep flocculation mechanism in Al13 and charge neutralization mechanism in Al30, and achieve the best synergistic optimization performance at Al13:Al30-7:3. Additionally, PDADMAC, as a polymer, could further enhance the charge neutralization ability of Al13 at low dosages and the sweep flocculation ability of Al13 at high dosages, respectively. However, an excessive dosage would lead to charge reversal and thus reduce the coagulation effect. Therefore, controlling the dosage was key when using Al-composite coagulants. The findings of our research could offer a certain theoretical foundation for the development of inorganic polymer flocculants.

Spongy polyelectrolyte hydrogel with Janus porous for solar-driven interfacial evaporation and sustainable seawater desalination

Janus-structured hydrogels exhibit excellent advantages in interfacial solar desalination due to their hydrophilicity and low evaporative enthalpy of evaporation, as well as the better salt resistance and mechanical properties. In this research, a simple one-step self-stratification foaming technique is employed to transform hydrogels into Janus structured for seawater desalination. Polyvinyl alcohol (PVA), poly (diallyldimethylammonium chloride) (PDADMAC), and a photothermal material (carbon black, CB) are mechanically stirred with a foaming agent (sodium dodecyl sulfate, SDS), allowing for full mixing and air incorporation, ultimately forming a sponge-like polymeric electrolyte hydrogel with abundant Janus pore structures (PANS-J). The formation of Janus pores in the hydrogel is attributed to the flocculation and high density of hydrophilic PDADMAC, causing it to sink during gelation while hydrophobic PVA floats to the surface. The Janus structure produced by this method reduces heat loss and enhances evaporation performance, achieving a pure water evaporation rate of 3.35 kg m−2 h−1 under sunlight (1 kW m−2). Moreover, quaternary ammonium ions on PDADMAC effectively separate anions and cations in saltwater, reducing salt ion diffusion into the evaporator, preventing premature pore structure blockage, and thus improving long-term evaporator performance which can improve the salt resistance and mechanical properties. By combining these advantages, Janus evaporators hold significant promise for solar-driven water purification and other applications.

The application of poly(dimethyldiallylammonium chloride) in poly(butylene adipate‐co‐terephthalate)/starch composites

AbstractAntimicrobial degradable materials are pivotal in enhancing food safety, mitigating plastic pollution, and advancing sustainable development. In this study, poly(diallyldimethylammonium chloride) (PDMDAAC) was initially anchored to the starch surface (PMS) and utilized as a filler. Subsequently, poly(butylene adipate‐co‐terephthalate) (PBAT)/PMS composites with antimicrobial properties were successfully prepared by melt blending. The results showed that the introduction of PMS filler can improve the mechanical and antimicrobial properties of PBAT. Compared with pure PBAT, the tensile strength and modulus of PBAT/10PMS composites were enhanced by 25% and 29%, respectively. In addition, the prepared PBAT/PMS composites exhibited excellent antimicrobial activity against Escherichia coli when the PMS filler content reached 10 wt% or even higher. Therefore, an antimicrobial biodegradable composite was successfully prepared using a facile blending method in this study.

Quaternization-based graft modification of straw fibers for conditioning the sludge dewatering performance.

Extracellular polymeric substances (EPS) are a critical influencing factor in sludge dewatering. Disrupting such EPS contributes to the release of bound water in sludge, enhancing the sludge dewatering performance. In This study, quaternized straw fibers that are destructive to the EPS structure and components in active sludge were prepared useing heterogeneous free radical graft polymerization. Straw fibers, dimethyl diallyl ammonium chloride (DMDAAC), ammonium persulfate (APS), and acrylamide (AM) were taken as the substrate, grafting monomer, catalyst, and cross-linking agent, respectively.The optimal processing conditions determined for the DMDAAC-based quaternization and graft modification of straw fibers were as follows: reaction temperature of 60 °C, reaction time of 5 h, 0.100 g of catalyst APS dosage per gram of straw, and 3.000 ml of DMDAAC dosage per gram of straw. The optimal processing conditions yielded 1.335 g of modified straw fibers per gram of straw, 33.67% grafting rate, and 31.70% substitution of the quaternary ammonium groups. The capillary suction time (CST) was conditioned from 243.3 ± 22.6 s in the original sludge to 134.5 ± 34.45 s. The specific resistance to filtration (SRF) was reduced from 8.82 ± 0.51 × 1012 m/kg in the original sludge to 4.59 ± 0.23 × 1012 m/kg.