Diallyldimethylammonium Chloride Research Articles

Polyelectrolyte complex membranes as a selective zincate separator for secondary zinc-air battery

Zinc-air batteries (ZABs) are being extensively studied as an alternative to lithium batteries due to their high energy density and overall safety benefit. While considerable attention has been given to the development of anodes and cathodes for ZABs, the separator membrane component has received relatively little focus. The separator is supposed to play a critical role in rechargeable ZABs by allowing hydroxide ions to permeate while blocking zincate ions. In this study, we investigated for the first time the potential use of polyelectrolyte complex (PEC) membranes as separators for rechargeable ZABs. These membranes were formed by mixing cationic poly(diallyldimethylammonium chloride) (PDADMAC) and anionic poly(sodium-4-styrenesulfonate) (PSS) at various molar ratios, followed by compression molding of the mixture precipitates after centrifugation. Among the different molar ratios tested, the non-stoichiometric PEC (2:1) membrane exhibited the highest ionic selectivity with a diffusion rate of 1.98 × 10−7 cm2 min−1 for Zn(OH)42−. Subsequently, the PEC membranes were integrated into homemade ZABs, and galvanostatic cycling tests were conducted. Overall, the PEC (2:1) membrane demonstrated superior separator ability for rechargeable ZABs compared to the other prepared molar ratios.

Nanoconfined Cathodic Electrochemiluminescence for Self-Sensitized Bioimaging of Membrane Protein.

Self-enhanced electrochemiluminescence (ECL) can be achieved via the confinement of coreactants and ECL emitters in a single nanostructure. This strategy has been used for the design of anodic ECL systems with amine compounds as coreactants. In this work, a novel confinement system was proposed by codoping positively charged ECL emitter tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+) and negatively charged coreactant peroxydisulfate (S2O82-) in silica nanoparticles. The codoping process could be performed by introducing S2O82- in cationic poly(diallyldimethylammonium chloride) (PDDA) to form PDDA@S2O82- and then encapsulating it and Ru(bpy)32+ in the Triton X-100 vesicle followed by the hydrolysis of tetraethyl ortosilicate, surface modification, and demulsification. The obtained RuSSNs exhibited good homogeneity, excellent monodispersity, acceptable biocompatibility, and 2.9-fold stronger ECL emission than Ru(bpy)32+-doped silica nanoparticles at an equal amount of nanoparticles in the presence of 0.1 M K2S2O8. Thus, an in situ self-sensitized cathodic ECL imaging method was designed for the monitoring of glycoprotein on living cell membranes. This work provides a new way for the modification, enhancement, and application of nano-ECL emitters in biological analysis.

PH-responsive LBL coated silica nanocarriers for controlled release of chlorhexidine

As resistant microbial strains continue to appear, antibiotic-based therapies become less effective. Hence, development of non-antibiotic antimicrobial delivery systems, such as those containing chlorhexidine, is urgently needed for the prevention and treatment of infections. For many biological applications as well as for efficient therapy, controlling the release kinetics of these antimicrobials is crucial. In this study, chlorhexidine was loaded into silica nanoparticles via layer-by-layer (LbL) coating technique. Different polyelectrolytes including polyacrylic acid (PAA), poly(diallyldimethylammonium) chloride (PDDA), poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonic acid) (PSS) were utilized in LbL coatings. Three types of coatings were studied: (1) PSS and PDDA (2) PAA and PAH (3) PSS and PAH. Zeta potential, transmission electron microscope, and a thermogravimetric analysis were used to characterize the nanoparticles. Acetate buffer pH 5 and PBS pH 7.4 were used as release media to assess the chlorhexidine release from nanoparticles. The chlorhexidine LbL-coated nanoparticles were effective in extending the duration of the medication release to 40 days. Chlorhexidine release was affected by pH of the release media and type of LbL coating, with a greater release at pH 5. PAA and PAH LbL coating had the highest amount of chlorhexidine release. This work illustrates that the LbL coating is an efficient technique for controlling the release of chlorhexidine from silica nanocarriers, with PAA and PAH coat being most effective among other polyelectrolytes tested. Different release profiles can be adapted for a variety of biomedical uses such as orthopedic or dental applications.

High performance chitosan/nanocellulose-based composite membrane for alkaline direct ethanol fuel cells

Polysaccharide anion exchange membranes (AEMs) containing chitosan (CS), cellulose nanofibrils (CNFs) and CNFs quaternized with poly(diallyldimethylammonium chloride) (CNF(P)s) were developed for use in alkaline direct ethanol fuel cells (ADEFCs). The resulting composite membranes prepared by the solvent casting process based on an experimental design were comprehensively assessed for morphology, KOH uptake, swelling ratio, EtOH permeability, mechanical properties, ionic conductivity, and cell performance. The fabricated CS-based composite membranes with CNF(P) fillers were superior to the commercial Fumatech FAA-3-50 membrane in terms of Young's modulus and tensile strength (69 % and 85 % higher, respectively), ion exchange capacity (169 % higher), and ionic conductivity (228 % higher). Single fuel cell tests have shown excellent performance of the CS-based membranes with CNF and CNF(P) fillers, as they exhibited up to 86 % improvement in power density at 80 °C compared to the commercial membrane (65.1 mW/cm2 vs. 35.1 mW/cm2) and higher maximum power density at all test conditions.

Cationic surfactant assisted electrostatic self-assembly of nitrogen-rich carbon enwrapped silicon anode: Unlocking high lithium storage performance

Nitrogen-rich carbon (N-rich-C) coating is attractive to enhance capacity, reduce resistance, and alleviate volume expansion of silicon anode in Li-ion batteries. However, the non-uniform coating of N-rich-C on silicon might restrict its optimum performance. In this study, poly(diallyldimethylammonium chloride) (PDDA) is employed as a cationic surfactant to tailor the surface potential of bare ball-milled Si particles, enabling the electrostatic self-assembly between Si particles and graphitic carbon nitride as the N-rich-C precursor. Continuous N-rich-C enwrapped ball-milled silicon (Si@N-rich-C) has been obtained after pyrolysis with a high N to C ratio of 0.65 and abundant pyridinic-N and pyrrolic-N, facilitating fast kinetic transport and accommodating more Li+ ion storage. Combined with the high capacity of Si, Li-ion cell with Si@N-rich-C electrode exhibits a high capacity of 1732 mAh g−1 after 200 cycles of charge-discharge at 400 mA g−1. At high-rate testing, Si@N-rich-C also maintains a high capacity of 1673 mAh g−1 at 1000 mA g−1. This study provides an effective approach for synthesizing high-capacity silicon anode for Li-ion batteries.

A novel sandwich-type electrochemical immunosensor for sensitive detection of zearalenone using NG/PDDA/HNTs and Ti-MOF-KB composites for signal amplification

In this work, a novel sandwich-type electrochemical immunosensor based on signal amplification was developed for the ultrasensitive detection of zearalenone (ZEA). The composite consisting of poly(diallyldimethylammonium chloride) functionalized nitrogen doped graphene, halloysite nanotubes and toluidine blue (Tb/NG/PDDA/HNTs), was synthesized for the first time. Then it was modified with gold nanoparticles (AuNPs) to bind the secondary antibody (Ab2, 10 μg mL−1) and form the tracer label. In addition, ketjen black (KB) was doped into titanium-based metal–organic framework (Ti-MOF), which provided large specific surface area and employed as the sensing platform to increase the immobilization of the primary antibody (Ab1, 10 μg mL−1). This immunosensor showed a wide linear range for ZEA from 10 fg mL−1 to 100 ng mL−1 with a limit of detection (LOD) as low as 0.57 fg mL−1, which was below the maximum tolerable levels (50∼100 µg kg−1) set by the United Nations Food and Agriculture Organization (FAO).

Molecular dynamic modeling of EPS and inorganic/organic flocculants during sludge dual conditioning

Extracellular polymeric substances (EPS) are the key components determining the dewatering behavior of wastewater sludge. However, current technical optimization of sludge conditioning for dewatering is limited by the poor understanding of the conditioner-EPS interactions at molecular levels. Herein, a combination of molecular dynamic (MD) simulations, dewaterability assessment and EPS characterization was used to reveal the sludge dewatering mechanisms using dual conditioning processes (prevalent inorganic (poly aluminum chloride (PAC)) and organic (poly dimethyl diallyl ammonium chloride (PDDA)). Results suggested that PAC and PDDA bridged the biopolymers mainly through electrostatic interactions, promoting the agglomeration of biopolymers and reducing their contact probability with water molecules. Water molecules were tightly bound to EPS mainly through hydrogen bonding with polar oxygen-containing functional groups. The adsorption of PAC and PDDA on hydrophilic components reduced the molecular polarity of biopolymers and altered the conformation of water molecules in the hydration shell, resulting in a decreased hydration capacity of EPS and the release of bound water, and sludge dewaterability was improved. PAC was found to be more effective than PDDA in disrupting the hydrogen bonding between water molecules and EPS, especially the protein β-sheet structure inside the molecular clusters with its high charge strength and diffusivity. Sludge bound water decreased by 73.16 % after PAC conditioning. In addition, PDDA exhibited superior agglomeration ability to biopolymers and promoted the electrostatic interaction between PAC and polar groups during dual conditioning. The strength and hydrophobicity of EPS molecular clusters were thus enhanced, and the conditioning efficiency was improved. This study offers molecular-level insights into the coagulation treatment process of sludge and provides theoretical references for process optimization and new conditioner development.

Self-supporting biocatalytic polyelectrolyte complex hollow fiber membranes via salt-dilution induced phase separation

The potential use of biocatalytic membranes in industries such as water treatment, pharmaceuticals, and medicine has attracted much interest in recent years. However, the use of organic solvents in traditional membrane fabrication techniques presents a challenge in the direct integration of enzymes during the membrane production. Thus, enzyme immobilization relies on consecutive modification steps (coating, binding, activation). Yet, recent progress in membrane fabrication using all-aqueous phase inversion of polyelectrolyte complexes (PEC) enables the direct incorporation of enzymes in the polymer solution. We present the fabrication of free-standing, defect-free and mechanically stable biocatalytic PEC hollow fiber membranes via the salt-dilution induced phase separation method. A polymer solution containing poly(sodium-4-styrenesulfonate) (PSS), poly(diallyldimethylammonium chloride) (PDADMAC), KBr, and the enzyme alkaline phosphatase (ALP) was extruded through a spinneret with a mixture of water and glycerol as lumen fluid into a water coagulation bath at 0 °C. The mechanical stability of the fibers is tuned by subsequent photo-induced cross-linking using 4,4’-diazidostilbene-2,2’-difulfonate tetrahydrate (DAS) and UV light. The resulting membranes have a molecular weight cut-off of 400Da, a pure water permeance of 1.5LMH/bar, and a burst pressure of 7bar. The immobilization of ALP proves successful, as the immobilized shows similar catalytic activity to that of the free enzyme, and both storage and thermal stability are improved. Moreover, the enzymes retain 70% of their initial activity after UV cross-linking with DAS and maintain their catalytic activity after repeated wash and filtration cycles. This work highlights the versatility of the fabrication of polyelectrolyte complex hollow fiber membranes via the salt-dilution induced phase separation, serving as a platform technology for the fabrication of porous, selective, and bioactive membranes.

Layer-By-Layer Assembly of Atomically Precise Alloy Nanoclusters Photosystems for Solar Water Oxidation.

Atomically precise metal nanoclusters (NCs) have garnered tremendous attention as light-harvesting antennas in heterogeneous photocatalysis due to unique atomic stacking mode, quantum confinement effect, and enriched active sites. However, metal NCs as photosensitizers suffer from extremely short carrier lifetime, poor photostability, and difficulty in carrier migration, which hinder the wide-spread utilization of metal NCs in solar energy conversion. To solve these problems, herein, Ag-doped glutathione (GSH)-capped gold NCs, i.e., alloy Au1- x Agx @GSH NCs and non-conjugated insulating polymer of poly(diallyl-dimethylammonium chloride) (PDDA) are utilized as the building blocks for layer-by-layer assembly of spatially multilayered alloy NCs/metal oxide (MO) photosystems. The alternately deposited ultrathin PDDA layer in-between Au1- x Agx @GSH NCs on the MO substrate functions as an efficient charge flow mediator to relay the directional photoelectron transfer over Au1- x Agx @GSH NCs, giving rise to the cascade charge transfer chain. This peculiar carrier migration mode endowed by exquisite interface configuration design significantly boosts the unidirectional electron migration from the Au1- x Agx @GSH NCs to the MO substrate, substantially improving the visible-light-driven photoelectrochemical water oxidation performances of MO/(PDDA-Au1- x Agx )n multilayer heterostructured photoanodes. The work will inspire the rational construction of alloy metal NCs-based photosystems for modulating spatially controllable charge transfer pathway for solar energy conversion.

Fabrication of amphoteric gelatin nanospheres-doped self-healing nanocomposite hydrogels and the application in flexible sensors

The nanomaterials with two distinct properties or components have outstanding advantages in the synthesis of smart hydrogels. In this work, gelatin nanospheres (GNPs) asymmetrically coated with poly(diallyldimethylammonium chloride) (PDDA) and tannic acid (TA) were synthesized by Pickering emulsion template method. The nanocomposite hydrogel with amphoteric gelatin nanospheres (GPTNPs)-doped was successfully prepared, which has excellent mechanical properties (strain = 616%, stress = 2.85 MPa) and self-healing properties (efficiency = 90.9%) under the synergistic effects of hydrogen bonding and metal coordination. The developed GPTNPs/polyacrylic acid (GPTNPs/PAA) hydrogel sensor exhibits high sensitivity (gauge factor (GF) = 3.69), quick response time (96.4 ms) and superior stability. Therefore, the GPTNPs/PAA hydrogels are excellent materials for application in wearable flexible sensors to monitor real-time human motion.

Mof-based basswood nanocomposite membrane of PDDA framework for ultrafast recognition and separation of ribavirin

The application system for membrane separation technology has been enlarged thanks to research and development into new technologies, however membrane separation still confronts many difficulties. This study uses vacuum self-assembly technology for the first time to combine in-situ grown metal–organic framework (MOF) basswood with poly dimethyl diallyl ammonium chloride (PDDA) ring framework to adsorb and separate ribavirin (RBV). The resulting imprinted film exhibits excellent adsorption capacity (49.2 mg g−1) and selectivity (better than 4.6) thanks to the numerous accessible imprinting sites provided by MOF that had previously been grown in situ on basswood and the synergistic effect of the PDDA ring framework. Dynamic permeation was utilized in this study to assess the membrane's stability, and the findings revealed that it consistently has a high separation factor (superior to 9) under specific pressure and time conditions. Furthermore, the synthesis process of MOF/layered PDDA framework-basswood membranes (MLFBMs) is facile and has little environmental impact. Last but not least, the aforementioned experimental findings and synthetic procedure demonstrate that the domains of selective separation, chemical engineering, and environmental protection can greatly benefit from the use of our MLFBMs synthesis technique.

Multi-objective optimization of a novel microalgae harvesting method based on buoy-bead flotation and feasibility analysis by life cycle assessment

Highly efficient microalgae harvesting is crucial for promoting the industrial application of microalgae bioenergy. In this study, positively charged sodium alginate microspheres (PCSAMs) were prepared, and the efficient harvest of Chlorella vulgaris (C. vulgaris) was realized based on the buoy-bead floatation method. A multi-objective optimization model was established to optimize the harvesting process, and the method’s feasibility was analyzed through life cycle assessment. The optimal harvesting efficiency and biomass concentration were 95.34% and 5.80%, respectively, and the corresponding costs were 5.13–5.16$/m3 and energy consumption was 0.065–0.066 kW h/m3. PCSAMs and C. vulgaris could form adhesion through electrostatic complementation, and poly dimethyl diallyl ammonium chloride (PDDA) long chain molecules formed “traps” on the surface of PCSAMs, improving the ability of PCSAMs to carry C. vulgaris. CO2 emissions during the harvesting process were only 0.065–0.066 kg/m3, which conforms to the carbon reduction policy and is more suitable for large-scale microalgae harvesting.

Reduced graphene oxide decorated with poly(diallyldimethylammonium chloride) for sensitive detection of acetaminophen in water and human urine samples

In this work, we have developed an efficient electrochemical sensor using screen-printed carbon electrodes (SPCE) modified by reduced graphene oxide-poly(diallyldimethylammonium chloride) (i.e., rGO-PDDA) composites to detect acetaminophen with superior sensitivity and excellent selectivity. The polymerization process resulted in a uniform PDDA coating along with chemically reducing rGO sheets in the presence of hydrazine, thus producing the rGO-PDDA composites. Adopting the Taguchi method with analysis of variances, an optimal parameter set (i.e., rGO/PDDA ratio 1:20, amplitude 100 mV, pulse width 100 ms, and pulse period 0.3 s) with a confidence level of 95% was derived for designing the electrochemical sensors. Accordingly, a linear fit of the signal output versus acetaminophen concentration (r2: 0.9973) was obtained in a wide concentration range (0.794–68.9 μM). The sensitivity of acetaminophen on the SPCE reaches as high as 1.76 μA/(μM cm2) with an ultralow detection limit of 0.0773 μM. The sensitivity of the prepared sensor was also confirmed through exploring the detection of acetaminophen on the SPCE with five interfering species including urea, p-cresol, ascorbic acid, ibuprofen, and 4-aminophenol. The prepared electrode was successfully applied for detecting acetaminophen level in human urine samples. We believed that the robust design of SPCE modified with rGO-PDDA composites demonstrated in this work enables engineering high-performance sensors with superior sensitivity, low detection limit, wide concentration range, and enhanced selectivity toward acetaminophen at ultralow concentrations.

Multifunctional wearable electronic textile based on fabric modified by MXene/Ag NWs for pressure sensing, EMI and personal thermal management

Flexible wearable electronics with multi-functions are bound to become the future development trend in the fields of intelligent device application, involving human healthcare, dynamic thermal management and even radiation protection. Herein, we promote a facile method that combines solution immersion and suspension spraying to assemble a poly(dimethylsiloxane)/Ag NWs/MXene/fabric (PAM@fabric) device. In particular, we use poly (diallyl dimethyl ammonium chloride) (PDAC) to pretreat the cotton fabric, which enables MXene to realize electrostatic self-assembly and greatly improve its stability. The multifunctional textile-based device with three-dimensional conductive network structure of MXene and Ag NWs presents durable and sensitive pressure sensing performance for detecting human joint motions and even subtle pulse. Besides, due to the excellent electrical conductivity of MXene and Ag NWs, the electronic also exhibits outstanding electromagnetic interference (EMI) shielding, as well as electrothermal conversion performance with controllability and extended cyclic stability. Accordingly, rational design provides a feasible path to prepare flexible multifunctional wearable devices.

Study on high-temperature degradation of acrylamide-based polymer ZP1 in aqueous solution

As exploration of deep and ultra-deep becomes more active, the utilization of acrylamide-based polymers as drilling fluid additives in challenging subsurface conditions, particularly at high temperatures, is growing. In this study, various monomers including acrylamide (AM), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and dimethyl diallyl ammonium chloride (DMDAAC) were used to synthesize an acrylamide-based polymer ZP1. Subsequently, 2.5 wt% aqueous solution of polymer ZP1 was subjected to a high-temperature degradation test at temperatures of 150, 180, 200, 220, and 240 °C, respectively. The degradation behavior of the polymer in aqueous solution and drilling fluid was investigated using various analytical techniques, including FT-IR, 1H NMR, XPS, GPC, TG-IR, and SEM. The research results indicate that the degradation temperature of the solid polymer sample was 258 °C, while in the solution at a temperature higher than 200 °C, the hydrolysis and imidation reaction in the polymer molecular chain was accelerated, which caused the main chain of the polymer to break easily. When the molecular weight (Mn) of the polymer decreased to less than 10,000, the protective influence of the polymer on the drilling fluid was lost, resulting in deterioration of the performance of the drilling fluid. However, the functional groups (amide groups, sulfonic acid groups, and quaternary ammonium groups) on the molecular chain of the polymer were retained.

A novel biomineralization-inspired flocculation approach for harvesting high quality microalgal biomass: Dual action of cationic polyelectrolytes and nanosilica

This study posed a novel biomimetic flocculation approach, aiming to efficiently harvest high-quality biomass of Scenedesmus quadricauda cultured with anaerobic digestate. Here, that poly(diallyldimethylammonium chloride) (PDADMAC) could serve as mimetic silicified proteins to spontaneously incorporate nanosilica onto microalgal cells, imparting diatom-like characteristics to S. quadricauda. Compared to the exponential growth phase (day 3), the highest harvesting efficiency (93.49%) was obtained at a lower dosage of PDADMAC (5 mg/g) in the stationary phase (day 6), which was attributed to changes in properties and composition of microalgal LB-EPS. On day 6, the hydrophobic functional groups in LB-EPS provided more binding sites during the flocculation process and formed a network structure of microalgal cells-flocculants-nanosilica. The resulting larger and more stable biomimetic silica shell promoted microalgal flocculation and sedimentation. Compared to conventional harvesting methods (centrifugation, polyacrylamide, alkaline flocculation), this method had the minimal negative impact on harvested biomass, with 9.95% of cell membranes damaged.

Electrostatic self-assembled MXene@PDDA-Fe3O4 nanocomposite: A novel, efficient, and stable low-temperature phosphating accelerator

In this study, MXene@PDDA-Fe3O4 binary hybrid (MPF) was synthesized by electrostatic self-assembly and incorporated into the low-temperature phosphating as an accelerator. MXene@PDDA-Fe3O4 with a large specific surface area exhibited excellent dispersion stability, structural stability, and the ability to selectively attract metal ions in the phosphating bath, which was conducive to the formation of the dense phosphating coating. The phosphate coating obtained from a phosphating bath containing 0.12 g/L MXene@PDDA-Fe3O4 (12-MPF coating) had the lowest porosity among all samples, which was decreased by 99.07% in comparison to the blank coating. Moreover, the EIS test revealed that 12-MPF coating exhibited the highest low-frequency impedance among all samples, which is more than an order of magnitude higher than that of blank coating, indicating that 12-MPF coating has excellent corrosion resistance. This notable improvement can be attributed to several factors, including the large specific surface area of MXene, the synergistic inhibitory effect of poly (dimethyl diallyl ammonium chloride) (PDDA) and Fe3O4 on agglomeration tendency of MXene, as well as the selective adsorption of Fe3O4 on metal ions. This study demonstrates the significant potential of the 0D/2D binary hybrid in phosphating treatment.

Guard Cell-Inspired Ion Channels: Harnessing the Photomechanical Effect via Supramolecular Assembly of Cross-Linked Azobenzene/Polymers.

Stimuli-responsive ion nanochannels have attracted considerable attention in various fields because of their remote controllability of ionic transportation. For photoresponsive ion nanochannels, however, achieving precise regulation of ion conductivity is still challenging, primarily due to the difficulty of programmable structural changes in confined environments. Moreover, the relationship between noncontact photo-stimulation in nanoscale and light-induced ion conductivity has not been well understood. In this work, a versatile design for fabricating guard cell-inspired photoswitchable ion channels is presented by infiltrating azobenzene-cross-linked polymer (AAZO-PDAC) into nanoporous anodic aluminum oxide (AAO) membranes. The azobenzene-cross-linked polymer is formed by azobenzene chromophore (AAZO)-cross-linked poly(diallyldimethylammonium chloride) (PDAC) with electrostatic interactions. Under UV irradiation, the trans-AAZO isomerizes to the cis-AAZO, causing the volume compression of the polymer network, whereas, in darkness, the cis-AAZO reverts to the trans-AAZO, leading to the recovery of the structure. Consequently, the resultant nanopore sizes can be manipulated by the photomechanical effect of the AAZO-PDAC polymers. By adding ionic liquids, the ion conductivity of the light-driven ion nanochannels can be controlled with good repeatability and fast responses (within seconds) in multiple cycles. The ion channels have promising potential in the applications of biomimetic materials, sensors, and biomedical sciences.

Immobilization of Microcystin by the Hydrogel-Biochar Composite to Enhance Biodegradation during Drinking Water Treatment.

Microcystin-LR (MC-LR), the most common algal toxin in freshwater, poses an escalating threat to safe drinking water. This study aims to develop an engineered biofiltration system for water treatment, employing a composite of poly(diallyldimethylammonium chloride)-biochar (PDDA-BC) as a filtration medium. The objective is to capture MC-LR selectively and quickly from water, enabling subsequent biodegradation of toxin by bacteria embedded on the composite. The results showed that PDDA-BC exhibited a high selectivity in adsorbing MC-LR, even in the presence of competing natural organic matter and anions. The adsorption kinetics of MC-LR was faster, and capacity was greater compared to traditional adsorbents, achieving a capture rate of 98% for MC-LR (200 μg/L) within minutes to tens of minutes. Notably, the efficient adsorption of MC-LR was also observed in natural lake waters, underscoring the substantial potential of PDDA-BC for immobilizing MC-LR during biofiltration. Density functional theory calculations revealed that the synergetic effects of electrostatic interaction and π-π stacking predominantly contribute to the adsorption selectivity of MC-LR. Furthermore, experimental results validated that the combination of PDDA-BC with MC-degrading bacteria offered a promising and effective approach to achieve a sustainable removal of MC-LR through an "adsorption-biodegradation" process.

Engineering Polymer-Assisted Self-Assembly Process for High-Capacity and Cycle-Stable Si-on-Graphite Anode of Li-Ion Batteries

A facile and ready for scale-up process based on polymer-assisted solution self-assembly is developed for manufacturing high-capacity and cycle-stable silicon-on-graphite (Si@G) lithium-ion battery anode materials. The process involves first coating a polyelectrolyte poly(diallyldimethylammonium chloride, anchored by a cross-linked polyvinyl alcohol-glutaraldehyde matrix, onto micron-sized graphite particles using spray-drying. Process optimization succeeds in imparting the graphite particles with a permanent high positive zeta potential (>40 mV), which enables attracting Si nanoparticles (NPs) (zeta potential= -28.5 mV) uniformly and firmly onto the graphite surfaces in water. Collected by filtration, the resulting Si@G composite particles are finally subjected to a high-temperature (1000 oC) treatment in Ar to turn the polymer coating into a carbon layer, which engulfs the Si NPs. A Si@G composite powder containing nearly 7 wt.% Si and produced in a batch size of approximately 20 gram is demonstrated to have a high specific capacity of 605 mAh g-1, a remarkable cycle stability showing only 11% capacity loss after 300 cycles and notably high coulombic efficiencies comparable to those of a graphite electrode upon cycling. The designed polymer coating realizes charge-carrying graphite particle without damaging its surface structure and eventually leads to a surface carbon layer that prevents Si NP detachment, improves powder conductivity, and mitigates solid-electrolyte-interphase formation.