Dimethyl Ammonium Research Articles

Two novel triazine-based quaternary ammonium salt Gemini surfactants as potential corrosion inhibitors for carbon steel in a sulfate-reducing bacteria solution: Experimental and theoretical studies

In this paper, two triazine ring–containing quaternary ammonium salt Gemini surfactants (C12-2-C12 and C14-2-C14) were synthesized. The minimum inhibitory concentrations against sulfate-reducing bacteria (SRB) of C12-2-C12, C14-2-C14 and dodecyl dimethyl benzyl ammonium chloride (1227) were determined using the double-dilution method. The performance of C12-2-C12 and C14-2-C14 in inhibiting carbon steel corrosion in the presence of SRB was examined, with 1227 serving as a control sample. The corrosion inhibition properties were assessed through static weight loss, electrochemical testing, and surface analysis. The interface adsorption behaviour of the corrosion inhibitor was explored via molecular dynamics simulations. Results indicate that the minimum inhibitory concentrations (MIC) of C12-2-C12 (0.021 mM) and C14-2-C14 (0.005 mM) are lower than that of 1227 (0.300 mM). The results of static weightlessness measurement reveal that the corrosion inhibition effects of the three surfactants on carbon steel soaked in SRB solution follow the order of C14-2-C14 > C12-2-C12 > 1227, with inhibition rates of 93.23 %, 88.45 %, and 76.49 % at a concentration of 0.2 mM, respectively. The adsorption behavior of these surfactants (1227, C12-2-C12, and C14-2-C14) on carbon steel surface in the presence of SRB conforms the Langmuir isotherm adsorption model. The outcomes of electrochemical experiments align with the static weight loss data. Furthermore, surface analysis results suggest that the surfactants can adsorb onto the carbon steel surface to form a protective film, thereby inhibiting SRB-induced corrosion.

Hydrogen bond-mediated assembly of homo-charged COF nanosheets and polyelectrolytes towards robust Li+/Mg2+ separation membrane

Developing membranes with ordered channels and high positive charge density is crucial for Li+/Mg2+ separation. Ionic covalent organic framework (COF) membranes are promising candidates, yet they face challenges like pore size mismatch with ions and the liable structural defects. Herein, we proposed a hydrogen bond-mediated strategy to assemble membranes from homo-charged COF nanosheets and polyelectrolytes. Compared with the quaternary amines in poly (diallyl dimethyl ammonium chloride), the abundant primary and secondary amines in polyethyleneimine facilitate multiple hydrogen bonding interactions with COF nanosheets. These interactions effectively overcome the electrostatic repulsion between positive charges, endowing membrane with structural robustness. Furthermore, the intercalation of polyelectrolytes eliminates the structural defects, reduces the membrane pore size, and enhances the Donnan effect. The optimized COF membrane exhibited a pure water flux of 10.2 L m−2 h−1 bar−1, separation factor of up to 30 at high Mg2+/Li+ mass ratio of 100, and excellent stability under various operating conditions. Strikingly, our strategy facilitates the fabrication of membranes in large area (>450 cm2) while maintaining consistent separation performance, showcasing substantial potential of scalable manufacturing.

Selective adsorption behaviors and mechanisms of benzyl quaternary ammonium salt on quartz and gypsum: A combined experimental and theoretical study

Benzyl quaternary ammonium salt is an effective collector of quartz from gypsum. To investigate the selective collection mechanism of tetradecyl dimethyl benzyl ammonium chloride (TDBAC) for quartz from a microscopic view, the adsorption experiments, first-principles calculations based on density functional theory (DFT), and molecular dynamics (MD) simulation were performed in this work. The adsorption experiment results show that the adsorption capacity of TDBAC on the quartz surface was 1.6 × 10−6 mol/m2, much larger than that on the gypsum surface (1.0 × 10−7 mol/m2). The interaction energy of TDBAC with quartz surface was −20202.98 kJ/mol, much smaller than that with gypsum surface (-78.37 kJ/mol). DFT calculation results indicate that the quartz surface was more likely to interact with TDBAC through electrostatic attraction since the average negative charge and exposure oxygen density of the quartz surface were both greater than those of the gypsum surface. After the adsorption of TDBAC, there were hydrogen bonds formed between the hydrogen atoms in TDBAC and the oxygen atoms on the quartz surface. This work confirmed that the highly selective adsorption of TDBAC on quartz surface was attributed to the strong electrostatic attraction and hydrogen-bond interaction.

Selective and fast oxidation of alcohol to aldehyde using novel catalytic deep eutectic solvent surfactants.

Deep eutectic solvent (DES) has been considered as a useful catalyst and reaction medium for various organic transformations. Herein, we report the catalytic application of novel deep eutectic solvent- based surfactant (DES surfactant) for the selective and fast oxidation of alcohols to aldehydes. The readily accessible DES surfactants (FeCl3/BHDC) was prepared using inexpensive ferric chloride (FeCl3) and benzyl hexadecyl dimethyl ammonium chloride in a simple manner. The synthesized FeCl3/BHDC was characterized using various techniques, including, FTIR spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and energy- dispersive X-ray spectroscopy (EDS) to determine its structure. The catalytic activity of FeCl3/BHDC in the selective oxidation of various alcohols to corresponding aldehyde derivative was investigated. The results showed the reaction could be completed within very short reaction times ranging from 2 to 15min, while achieving good to excellent yields. This protocol offers a facile strategy and excellent efficiency in selectively oxidizing various alcohol derivatives to their respective aldehydes and ketones, utilizing hydrogen peroxide in the presence of catalytic DES surfactant.

A cationic polyelectrolyte for enhancing dewatering of montmorillonite-containing coal slime: adsorption and modification mechanism

ABSTRACT In this study, a cationic polyelectrolyte (Poly dimethyl diallyl ammonium chloride, PDADMAC) was introduced as a filter aid to enhance the dewatering effect of montmorillonite (MT)-containing coal slime, and compared with cationic polyacrylamide (CPAM). The dewatering performance of PDADMAC and CPAM was evaluated based on vacuum filtration experiments. The modification mechanism of PDADMAC on Mt particle surface was revealed by filter cake pore distribution, zeta potential, contact angle and Atomic Force Microscopy (AFM). The adsorption difference between PDADMAC and CPAM on Mt surface was studied by Density Functional Theory (DFT). In addition, DLVO theory further explains the mechanism of PDADMAC enhancing dewatering from the perspective of interaction force. The optimal dosage of PDADMAC was 125 g/t, and the filter cake moisture content was reduced by 3%. Compared to CPAM, PDADMAC achieves efficient dewatering at a lower dosage. PDADMAC has a more prominent ability to neutralize charge, and its effect on interparticle interactions was a potential mechanism to promote dehydration.

Silica surface modification using cellulose as a renewable organosilane derived from coconut coir fiber for carbon capture

The properties of silica surface modification for carbon capture were studied, utilizing cellulose-amine as a modification agent derived from dissolved coconut coir fiber. To form bonds with NH2 functional groups through amination processes, cellulosic biomass waste is utilized, which is analogous to replacing alkoxy ligands. The dual-function mixture reagents dimethyl sulfoxide (DMSO) and ammonium hydroxide (NH4OH) were employed in the same system as the amine sources and solvents. Waterglass is used as a source of silica, and the modified particles are formed using a one-step consecutive sol-gel spray drying process used in a direct condensation route. Changes in the concentration of sodium lauryl sulfate (SLS) were examined to determine how they affected the essential parameters of the particles. The template is removed during particle formation without further physical or chemical processing. The particle morphology changed from donut-shaped to spherical after SLS application, as evidenced by the increase in SLS concentration. This also shows that the increase in the particle surface area is directly influenced by the increase in the formation of new pore structures with increasing SLS concentration. Through this mechanism, it is possible to extend the pore size distribution to the meso-macropore regime and initiate the formation of new mesopores. This has a direct impact on the capacity to absorb CO2 gas by increasing the cellulose-amine mass fraction that can be grafted to as high as 32.35 %wt. At an operating pressure of 6 bar, a maximum CO2 gas adsorption capacity of 5.32 mmol/g silica was attained by adding SLS 3 CMC to the silica particles. This value is 2.3 times higher than that obtained when using an aminosilane-based modification agent.

Self-assembled conductive coating and bifacial microstructures Collaboratively Adjusting the sensing performance and high reliability of the flexible pressure sensors

Flexible pressure sensors are being studied intensively for applications such as smart wearables and health monitoring. While ensuring the excellent sensing performance, the reliability (durability and environmental resistance) of the sensors are also key indicators that determine whether they can be used in practice. In this research, a strategy to adjust the sensing performance and high reliability of the flexible pressure sensors by self-assembled conductive coating and bifacial microstructures (BM) is proposed. Polydimethylsiloxane/carbon nanotube films with BM are first modified to reduce the surface contact angle. Then poly(dimethyl diallyl ammonium chloride) (PDAC) and hydroxylated carbon nanotubes/carboxylated cellulose nanofibers/glycerol (CNT-OH/CNF-C/GL) are successively assembled on the BM surface to construct conductive coatings (PCCG). The sensor based on PCCG and BM (the PCCG-BM sensor) shows a high sensitivity (9.97 kPa−1), a wide detection range (0–330 kPa), and a fast response time (59 ms). The PCCG-BM sensor has excellent repeatability, and it still outputs stable current change signals after 240,000 pressure cycles. What’s more, the PCCG-BM sensor is treated with extreme environments such as bending, stretching, washing, and high pressure, and the sensor still maintains excellent performances. This preparation strategy provides a new perspective for the fabrication of high-performance and high-reliability flexible sensors.

Insight into didecyl dimethyl ammonium bromide toxicity following acute exposure in pullets (Gallus gallusdomesticus).

Didecyl dimethyl ammonium bromide (DDAB) is a quaternary ammonium compound used for the sanitation of drinking water of poultry and water pipelines in farms. There is scarcity of information on the toxicology of DDAB in poultry. This study set out to profile the acute toxicity of DDAB in poultry. Issa brown pullets (n = 34) as experimental birds were orally administered varying doses of DDAB, using a syringe, after 12h fasting, and observed for toxicity over 14 days. Control birds (n = 10) were similarly given normal saline orally. Toxic signs in the experimental birds were depression, anorexia, adipsia, vocalization with foamy salivation, later emaciation and death. The LD50 was calculated as 458.00mg/kg. Birds given 2151mg/kg DDAB died within 24h, while those treated with 516mg/kg succumbed on Day 14. At necropsy, grossly, there were necrosis and sloughing of the oesophagus and intestines, pale and friable liver, congested and necrotic lungs, friable popped out kidneys and emaciated carcasses. Microscopically, desquamation and necrosis of the oesophagus, crop, proventriculus and intestines and disruption of the koilin membrane of the gizzard were observed. The lungs, liver and kidneys were congested with mononuclear cellular infiltration plus loss of architecture in the lungs and liver. In conclusion, at high doses, DDAB caused significant toxicity in chickens and these findings provide new information which could serve as a guide in the diagnosis of quaternary ammonium toxicity in chicken. The results could be extrapolated to other quaternary ammonium toxicities in related avian species.

Synthesis and Characterization of New Copper(II) Coordination Compounds with Methylammonium Cations

We synthesized four new copper(II) complexes with acetato and chlorido ligands and methylammonium (MA), dimethylammonium (DMA), and tetramethylammonium (TMA) counterions: (MA)4[Cu2Ac4Cl2]Cl2·2H2O (1), (DMA)2[Cu2Ac4Cl2] (2), (DMA)4[Cu2Ac4Cl2]Cl2·2H2O (3), and (TMA)5[Cu2Ac4Cl]Cl4·4H2O (4). All compounds were characterized by single-crystal X-ray diffraction, magnetic measurements, FTIR spectroscopy, and thermogravimetric analysis. Complexes 1, 2, and 3 consist of a dinuclear coordination anion [Cu2(Ac)4Cl2]2− with bridging acetato ligands arranged in a paddle-wheel conformation and square-pyramidal coordination around Cu(II) atoms, while the coordination anion in compound 4 is a polymeric chain, parallel to the c axis, with Cu2(Ac)4 units connected through bridging chlorido ligands. Magnetic measurements carried out between 2 K and 300 K indicate strong antiferromagnetic interactions between Cu(II) ions. The effective magnetic moments range from 1.94 μB to 2.21 μB, exceeding the spin-only value for Cu(II) ions (μeff=1.73 μB) and suggesting significant orbital contributions to the magnetic moment. Thermogravimetric analysis of all complexes showed a multistep decomposition behavior yielding elemental copper as the final product.

Surfactant-mediated enhancement of liquid permeability in scots pine wood

Scots pine (Pinus sylvestris L.) is a widely-used wood species in construction and exterior applications. However, inherently low liquid permeability of wood presents substantial challenges to processing efficiency. In order to improve the liquid permeability in Scots pine, the effect of two different surfactants including dodecyl dimethyl ammonium chloride (DDAC) and primary alcobol ethoxylate (JFC-U) were investigated in this study. The mechanism was unveiled by microscopic observation, chemical analysis of extractive composition, and molecular dynamics (MD) simulations. The results demonstrated that both surfactants increased the liquid absorption in Scots pine by 14.7–46.3 % within 0.5 h. This effect was mainly attributed to the surfactants' capability to enhance surface wetting and dissolve extractives deposited on pit membrane in Scots pine wood. DDAC outperformed JFC-U in dissolving extractives. The MD simulations between DDAC and stearic acid (a representative extractive) illustrated that DDAC could envelope stearic acid molecules and form micellar structures through the strong intermolecular forces between them. These findings provide valuable insights into the effect and mechanisms by which surfactants enhance liquid permeability in extractive-rich wood, therefore, to support the development of efficient wood treatment technologies.

In Vitro Metabolism of Quaternary Ammonium Compounds and Confirmation in Human Urine by Liquid Chromatography Ion-Mobility High-Resolution Mass Spectrometry.

Quaternary ammonium compounds (QACs) are high-production chemicals used as cleaning and disinfecting agents. Due to their ubiquitous presence in the environment and several toxic effects described, human exposure to these chemicals gained increasing attention in recent years. However, very limited data on the biotransformation of QACs is available, hampering exposure assessment. In this study, three QACs (dimethyl dodecyl ammonium, C10-DDAC; benzyldimethyl dodecylammonium, C12-BAC; cetyltrimethylammonium, C16-ATMAC) commonly detected in indoor microenvironments were incubated with human liver microsomes and cytosol (HLM/HLC) simulating Phase I and II metabolism. Thirty-one Phase I metabolites were annotated originating from 19 biotransformation reactions. Four metabolites of C10-DDAC were described for the first time. A detailed assessment of experimental fragmentation spectra allowed to characterize potential oxidation sites. For each annotated metabolite, drift-tube ion-mobility derived collision cross section (DTCCSN2) values were reported, serving as an additional identification parameter and allowing the characterization of changes in DTCCSN2 values following metabolism. Lastly, eight metabolites, including four metabolites of both C12-BAC and C10-DDAC, were confirmed in human urine samples showing high oxidation states through introduction of up to four oxygen atoms. This is the first report of higher oxidized C10-DDAC metabolites in human urine facilitating future biomonitoring studies on QACs.

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.

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.

Synthesis of Newly Ester Type Gemini Cationic Surfactants: Surface Properties, Fabric Softness and Antibacterial Properties

AbstractFour ester cationic Gemini surfactants (EDQ‐n, n represents the carbon number in the raw fatty acid of 12, 14, 16 and 18) were synthesized from fatty acid, N, N‐dimethylethanolamine and 1, 4‐dibromobutane by two‐step reaction of esterification and quaternization. Their surface activities at air/water interface were investigated. The application performance such as water solubility, antistatic property, fabric softness, fabric whiteness, biodegradability, and antibacterial activities were tested and compared with traditional quaternary ammonium salt. The results showed that the γcmc increases with increasing the hydrophobic chain length and EDQ‐12 presented the highest surface activity. The diffusion coefficients calculated from the Ward‐Tordai equation indicates the adsorption process is a mixed‐diffusion kinetic adsorption mechanism. The water solubility of EDQ‐n is higher than dioctadecyl dimethyl ammonium chloride (D1821) and ester quaternary ammonium salt (Esterquats). The fabric softness and whiteness properties of EDQ‐16 and EDQ‐18 are similar to D1821 and Esterquats, which can significantly reduce the cotton fabric softness and have no significant difference in whiteness retention. EDQ‐n demonstrated more readily biodegradation(>90 %) than D1821(0 %) after seven days. In addition, EDQ‐12 and EDQ‐14 show excellent antibacterial activities against Staphylococcus aureus and Escherichia coli in comparison with conventional bacteriostatic agent didecyl dimethyl ammonium chloride (DDAC).

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.

A green UV-resistant Natural rubber-Polydopamine-TiO2@SiO2 composite with high mechanical properties based on an electrostatic adsorption effect

Abstract Antioxidants are usually added into the natural rubber (NR) to resist the oxidation caused by the ultraviolet (UV) irradiation, while commonly used antioxidans are usually organic and prone to decomposition and migration. The inorganic UV absorbers like titanium dioxide nanoparticles (TiO2) and silicon dioxide (SiO2) can maintain chemical stability under UV radiation, while the hydroxyl radicals from electron-hole pairs in TiO2 would damage NR matrix and the poor compatibility of TiO2 with NR limited the process. Therefore, inert SiO2 is coated on TiO2 (TiO2@SiO2) to reduce its photocatalytic activity, and polydopamine (PDA) is coated on rubber to improve stability. The strong light-absorbing properties of PDA could also improve the UV-resistant ability of NR. Besides, poly (sodium-p-styrenesulfonate) (PSS) coating NR-PDA provides the matrix negative charge, and polydiallyl dimethyl ammonium chloride (PDDA) wrapped around TiO2@SiO2 can give a positive charge, thus moderating the compatibility between the filler and the matrix through electrostatic adsorption. The green UV-resistant natural composite NR-PDA TiO2@SiO2 was fabricated. The composites exhibited strong tensile strength and excellent UV-resistant properties, which particularly extend the service life of rubber products as UV-shielding materials, thus showing significant potential in extreme environments.

Photogalvanics of the platinum working electrode in the Allura Red d-Galactose-didecyl dimethyl ammonium chloride-NaOH electrolyte

Photo-galvanic cell is a photochemical cell device whose performance depends on the combination of several factors like dye and reductant concentrations, dye stability, pH, light intensity, electrodes used, Pt electrode area, diffusion length, etc. An entirely new and unexplored combination of platinum with Allura Red photosensitizer, d-Galactose reductant, and didecyl dimethyl ammonium chloride (DDAC) surfactant has been explored in present research to upgrade the electrical performance of these cells. Allura Red is a water-soluble azo dye which shows good absorbance in region 501–507 nm. The Allura Red and DDAC is an anionic and cationic species, respectively, and therefore, the opposite charges of dye and surfactant molecules are expected to form a stable dye-surfactant complex enhancing the dye solubility and stability. d-Galactose has been used for its good reducing properties. This unexplored combination of Pt-Allura Red-d-Galactose-DDAC with these characteristics has encouraged further enhancement of the electrical output of the photogalvanic cells. The electrical output, stability, and spectral property of the photogalvanic cells have been studied in the present work. The observed power, current, potential, efficiency, and storage capacity (as half time) are of the order of 443.8 µW, 2400 µA, 721 mV, 11.61%, and 28 min, respectively. These observed results are higher than some reported data. In the spectral study, nearly the same band intensity of the pre-illuminated and post-illuminated electrolyte solution shows quite good photo-stability of the Allura Red dye in electrolyte form. This new combination of platinum-electrolyte still has the scope to achieve the enhanced cell performance of photogalvanic cells for future development.

Gemini cationic surfactant of 1, 3-bis (dodecyl dimethyl ammonium chloride) propane as a novel excellent inhibitor for the corrosion of cold rolled steel in HCl solution

Gemini surfactants have become the research focus of novel excellent inhibitors because of their special structure (two amphiphilic moieties covalently connected at head group by a spacer) and excellent surface properties. It is proved by theoretical calculations that 1, 3-bis (dodecyl dimethyl ammonium chloride) propane (BDDACP) molecules can perform electron transfer with Fe (110). And it has a small fraction free volume, thus greatly reducing the diffusion and migration degree of corrosive particles. The potentiodynamic polarization curve showed that coefficients of cathodic and anodic reaction less than 1 and polarization resistance increased to 1602.9 Ω cm−2 after added BDDACP, confirming that BDDACP significantly inhibited the corrosion reaction by occupying the active site. The electrochemical impedance spectrum of imperfect semi-circle shows that the system resistance increases and double layer capacitance after added BDDACP. Weight loss tests also confirmed that BDDACP forms protective film by occupying the active sites on steel surface, and the maximum inhibition efficiency is 92 %. Comparison of the microscopic morphology showed that steel surface roughness was significantly reduced after added BDDACP. The results of time-of-flight secondary ion mass spectrometry show that steel surface contains some elements from BDDACP, which confirms the adsorption of BDDACP on steel surface.

Improving rate performance of FeC2O4/rGO composites on lithium storage via single-polymerization‐induced electrostatic self‐assembly

Based on the wide interlayer distance for ions diffusion, iron (II) oxalate exhibits excellent lithium storage ability. However, the local deposition of metallic nanoparticles of Fe0 leads to low electrochemical reactivity, which hinders the actual application of FeC2O4 in large current regions (>5C). To solve this problem, a strong cationic polymeric electrolyte, polyelectrolyte diallyl dimethyl ammonium (PDDA), was introduced to construct a [FeC2O4(PDDA)]+ ligand. By single-polymerization‐induced electrostatic self-assembly, the [FeC2O4(PDDA)]+ ligand was combined with the surface-charged rGO to produce a FeC2O4/rGO material. It is proved that the rGO carrier improves the interparticle conductivity, electrochemical activity and structure stability of the iron (II) oxalate particles, ensuring the stability of Li || FeC2O4/rGO battery at a rapid charging rate of 20C (8 A g−1) for more than 500 cycles (with the special capacity of 713 mAh g−1). Compared with FeC2O4 electrode, owning to high reactivity of rGO and continuously activating on the nanoscale Fe metal generated at ∼0.75 V, FeC2O4/rGO shows higher electrochemical activity of conversion reaction in the first 50 cycles and better reversibility in the rate charge–discharge test (the capacity rapidly increased to 1158.8 mAh g−1 after 20C cycles). This work reveals how the structural design of conducting and supporting the carrier can achieve fast charging for iron (II) oxalate lithium-ion batteries.

Insight into the responses of performance, bacterial community and three-fraction resistance genes to different quaternary ammonium compounds in nitrifying system under the stress of environmental ciprofloxacin

In recently years, an increasing number of quaternary ammonium compounds (QACs) enter waster wastewater treatment plants (WWTPs), and coexist with the environmental antibiotics in WWTPs. In this study, dodecyl trimethyl ammonium chloride (ATMAC-C12), dodecyl benzyl dimethyl ammonium chloride (BAC-C12) and didodecyl dimethyl ammonium chloride (DADMAC-C12) were added to nitrifying system treating sewage containing environmental concentration of ciprofloxacin (CIP) (0.2 mg/L), respectively, to explore the different responses of resistance genes (RGs) under the co-occurrence of different kinds of QACs and CIP in nitrifying system. Results showed that partial nitrification was achieved by QACs and CIP co-loading, and the co-occurrence of ATMAC-C12 and CIP had more serious inhibitory in the ammonia oxidation activity, functional genes, extracellular polymeric substances (EPS), and bacterial community structures than BAC-C12 and DADMAC-C12 in nitrifying system. Moreover, the co-occurrence of ATMAC-C12 and CIP stimulated the proliferation of more intracellular RGs in sludge (si-RGs), while more extracellular RGs in sludge (se-RGs) and RGs in water (w-RGs) were enriched under the co-occurrence of DADMAC-C12 and CIP. Mobile genetic elements (MGEs) cooperated with bacteria to alter the profiles of RGs. Partial least-squares path model further confirmed that MGEs had positive effects on the proliferation and transmission of si/se/w-RGs (λ = 0.647, 0.918 and 0.627), and EPS had a most important effect (λ = 1.163) on the w-RGs under the co-occurrence of QACs and CIP. Therefore, it should pay attentions to the consumptions of QACs, and avoid the proliferation and transmission of RGs caused by the co-occurrence of QACs and environmental antibiotics.