Chloride Modification Research Articles

Boosting the visible-light-driven photocatalytic antibacterial performance of MoS2 nanosheets by poly(3-(4-methyl-3'-thiophenoxy))propyltrimethylammonium chloride (PThM) modification.

Molybdenum disulfide (MoS2) has been reported to possess photocatalytic bactericidal ability, but its efficiency is not high. In this paper, a water-soluble cationic conjugated polymer, poly(3-(4-methyl-3'-thiophenoxy))propyltrimethylammonium chloride (PThM), was designed to modify MoS2 and boost its antibacterial abilities. Another hydrophobic conjugated polymer, polythiophene (PTh), was synthesized and composited with MoS2, and this was compared with PThM/MoS2 from the perspective of composite effectiveness. Studies involving the photo-disinfection of Escherichia coli (E. coli) under visible-light irradiation (30 W) showed that the antibacterial efficiencies were in the following order: PThM/MoS2 > PTh/MoS2 > MoS2. The enhanced bactericidal activities of PThM/MoS2 and PTh/MoS2 were attributed to the conjugated polymers restraining the recombination of photogenerated carriers in MoS2, thereby increasing the generation of reactive oxygen species (ROS). PThM/MoS2 presented the best antibacterial efficiency because its cationic side-chains improved the solubility of the material and promoted contact between bacteria and the material. This work may provide some insights into the design of practical nano-antibacterial materials.

Effects of chloride ions on flower-like Ag-coated ZnO nanorod arrays and the Raman enhancement

Chloride solutions are used to modify flower-like Ag-coated ZnO nanorod (Ag-ZnO-NR) arrays, leading to the formation of Ag-nanosphere decorated ZnO-NR arrays, which have a morphology with each sphere-like Ag nanoparticle independently lying at the top of ZnO-NR and thus can be used as a new kind of substrates for the study of surface-enhanced Raman spectroscopy (SERS). The chloride modification is dominated by Ag abnormal migration on ZnO NRs in the environment of chloride solution. The concentration of chloride ions for effective modification is higher than ∼1 × 10−4 M and the final morphology is nearly steady as the soaking time is longer than 10 min. On the modified SERS substrates, the thermalization of probing molecules during Raman measurement is substantially depressed. Using the SERS samples prepared by loading the probing molecules in the presence of chloride ions, the Raman signals are obviously enhanced with an extremely high signal-to-noise ratio. The Raman enhancement is evidenced to be due to the enhanced adsorption of probing molecules on Ag surface in the presence of chloride ions.

Preparation and characterization of modified corn stalk biochar

To increase the added value of corn stalk and improve the performance of corn stalk biochar, magnesium chloride (MgCl2) was used to modify biochar, and the effects of temperature on the structure and properties of modified biochar were considered. With the increase of temperature, the yield of biochar decreased. There was a marked increase in the number of mesopores and micropores, but the mesopore pore diameter changed to a smaller pore diameter, and the specific surface area remarkably increased. As the temperature increased, the content of C increased, while the range of H and O decreased. In addition, the number of oxygen-containing functional groups and methyl groups decreased, indicating that the structure of biochar became more aromatized. An obvious Mg(OH)2 crystal peak appeared in the X-ray diffraction pattern, which meant that Mg ions were loaded on the surface of biochar. Moreover, the highest removal rate of methylene blue dye by biochar was 83.6%. The authors conclude that temperature and magnesium chloride modification can improve and enhance the performance of corn stalk biochar. These findings will help deepen people’s understanding of biochar modification and serve as a reference for future related research.

Reactive nano-essential oils for sustained release of essential oils and application to wallpaper

Essential oils are a volatile and aromatic substance with a variety of active biological activities. However, the excessive volatility and inconvenience of the use of essential oils limit their applications. In this study, we developed a reactive mesoporous silica nanoparticle (rMSNs) based on cyanuric chloride modification for essential oil encapsulation and commodity adhesion. The large pore volume and specific surface area of rMSNs facilitate the nanoparticles adhering to a large amount of essential oil and achieve the sustained release of essential oil, thus prolonging the fragrance retention time of essential oils. The reactive nano-essential oils can form covalent bonds with the wallpaper, thereby remarkably improving the adhesion of the reactive nano-essential oils on the wallpaper and preventing the reactive nano-essential oil from de-adhering from the wallpaper. The active nano essential oil simultaneously overcomes the intense volatility of the essential oil and inconvenience in use, has a simple preparation process and low cost, and has great application potential.

A Sodium Chloride Modification of SnO2 Electron Transport Layers to Enhance the Performance of Perovskite Solar Cells.

A sodium chloride modification was applied where different amounts of sodium chloride was physically blended in a tin oxide colloid solution to passivate the interface between the electron transport layer (ETL) and perovskite layer and improve the performance of perovskite solar cells. Sodium chloride-modified tin oxide was utilized as the electron transport material to fabricate perovskite solar cells. It was found that sodium chloride-modified tin oxide as an ETL could considerably enhance the performance of the device compared to pristine tin oxide. The power conversion efficiency of the perovskite solar cell displayed 8.8% remarkable improvement from 18.7 ± 0.4% to 20.3 ± 0.3% on average and 9.5% improvement from 18.9 to 20.7% in champion devices because of the considerable enhancement of the fill factor when 25 mM sodium chloride-modified tin oxide as the ETL was used in comparison with pristine tin oxide.

Selective Photocatalytic Reduction of CO2 to CH4 Modulated by Chloride Modification on Bi2WO6 Nanosheets.

Solar-driven photocatalytic CO2 reduction into CH4 with H2O is considered to be a promising way to alleviate the energy crisis and greenhouse effect. However, current CO2 photoreduction technologies tend to overlook the role of photooxidation half reaction as well as the effect of the protons produced by water oxidation on CH4 generation, resulting in low CO2 conversion efficiency and poor CH4 selectivity. In the present study, a series of chloride-modified Bi2WO6 nanosheets were constructed in view of chloride-assisted photocatalytic water oxidation. The results show that the CH4 yield of the synthesized sample can be enhanced up to about 10 times compared to that with no Cl- modification. Besides, the selectivity of CH4 can be regulated by the loading amount of chloride, varying from 51.29% for Bi2WO6 to 94.98% for the maximum. The increase of product yield is attributed to chloride modification, which not only changed the morphology of the catalyst, but also modified the pathway of water oxidation. Further studies on intermediate products and the density functional theory calculation confirm that the Cl- ions on Bi2WO6 nanosheets not only promote H2O oxidation, but also lower the energy barrier for intermediate *CHO generation, thus facilitating CH4 production. The results gained herein may provide some illuminating insights into the design of a highly selective photocatalyst for efficient CO2 reduction.

Zinc chloride modification of sage leaves powder and its application as an adsorbent for KMnO4 removal from aqueous solutions

Sage Leaves Powder was modified by 30% w/w of Zink Chloride (ZnCl2) and used as a cheap adsorbent for potassium permanganate (KMnO4) adsorption from aqueous media. The characterization of the synthesized adsorbent showed diversity in its functional groups at 1030, 1700, and 2930 cm−1. The impact of experimental conditions on the adsorption was investigated. It was found that these experimental conditions except pH have positive effects on the efficiency of this adsorbent. The initial KMnO4 concentration of 1500 mg l−1, the temperature of 60 °C and the solution pH of 1.5 were found to be the ideal conditions in this adsorption. The equilibrium data were analyzed using three isotherm models. Langmuir model was found to be the best model applied in this work. The adsorption capacities were 714.29, 769.23, 833.33 and 909.09 (mg g−1) at 30, 40, 50 and 60 (°C), respectively. The parameters of the adsorption kinetics were evaluated by three kinetic models. The kinetic results confirm that the 2nd order described well the experimental data. Thermodynamic outcomes suggest that this adsorption is a spontaneous and endothermic process. The obtained results make from this adsorbent a good option for KMnO4 removal from wastewater in terms of its low-cost and adsorption performance.

STUDY ON THE REMOVAL OF AMMONIA IN WASTEWATER USING ADSORBENT PREPARED FROM RICE HULL WITH MAGNESIUM OXIDE MODIFICATION

This study is aimed to evaluate the ability of magnesium oxide-coated carbonized rice hull (MCRH) material for ammonium removal in synthetic and real domestic wastewater. The MCRH material was prepared using waste rice hull from a household rice-processing factory and magnesium chloride salt via a simple mixing and annealing method. The material was then characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The effects of magnesium chloride modification and environmental condition such as initial ammonium concentration (20 – 100 mg/L), amount of adsorbent (0.8 –2.0 g/L), and adsorption time (0 –32 h) on the ammonium removal efficiency and adsorption capacity were investigated. Adsorption kinetic and isotherms were also studied for MCRH material. Results showed that magnesium oxide was successfully coated on carbonized rice hull with Mg/C molar ratio of 0.22. Ammonium adsorption isotherm fitted well to Langmuir model with maximum adsorption capacity of 65.36 mg/g. The adsorption was physical process and adsorption kinetic was best described by intra-particle diffusion model with the correlation coefficients ranged from 0.942 – 0.979. Ammonium removal feasibility of MCRH was proved through the treatment of real domestic wastewater containing 80.7±1.6 mg/L initial ammonia concentration with removal efficiency reached 86.8% and the effluent concentration met the allowable value (10 mg/L) as given by QCVN 14 : 2008/BTNMT (column B) - National technical regulation on domestic wastewater. Hence MCRH is potential as a cheap and abundant material in Vietnam and the material after adsorption accumulated ammonium would be the source of fertilizer for soil quality improvement.

Study on synergistic effect of removal of nitrogen and phosphorus by mixed modified zeolite

Sodium chloride-modified zeolite Z-Na for the removal of ammonia nitrogen and lanthanum-modified zeolite Z-La for the removal of phosphorus were prepared by sodium chloride modification and lanthanum chloride modification. Through adsorption kinetics and isotherm model fitting, the synergistic effect of pollutants in the removal of ammonia nitrogen and phosphorus by these two zeolites was explored. The results show that in the case of composite pollutants, the presence of phosphorus can inhibit the adsorption of ammonia nitrogen by Z-Na, (the adsorption rate is reduced from 2.3840ℎ−1 to 1.3442ℎ−1, and the maximum adsorption capacity is 13.6612mg / g reduced to 11.8906mg / g);the presence of ammonia nitrogen will promote the adsorption of phosphorus by Z-La (adsorption rate increased from 1.0623ℎ−1 to 4.8595ℎ−1, while the maximum adsorption capacity is almost unchanged).

Seaweed bio-chars modified with metal chloride for elemental mercury capture from simulated flue gas

Metal chloride-impregnated seaweed bio-chars, derived from waste algae (Enteromorpha), are served as solid sorbents for Hg0 capture from simulated flue gas. The impacts of various metal chloride modification on Hg0 removal performance, i.e. FeCl3, CuCl2, ZnCl2, CoCl2, and CeCl3, are studied. The results display that the Hg0 removal performances of Enteromorpha derived bio-chars are greatly enhanced by immersing metal chlorides. FeCl3-and CeCl3-modified bio-chars exhibits the optimal Hg0 removal performance. Oxygen and NO show a promotional effect on Hg0 removal, whereas H2O suppresses Hg0 adsorption. Lower concentration of SO2 favors Hg0 removal, but higher concentration of SO2 inhibits Hg0 adsorption. Hg0 is oxidized by covalent chloride groups and metal oxides on the metal chloride-impregnated bio-chars.

Preparation, characterization, and emulsification properties of agarose fatty acid derivatives with different hydrophobic chains

Two types of fatty acid derivatives were used to synthesize agarose fatty acid esters in a heterogeneous medium. Agarose esters with low degree of substitution were synthesized with succinic anhydride, octenyl succinic anhydride, dodecyl succinic anhydride as esterifying agents. Agarose esters with high degree of substitution were synthesized with lauroyl chloride, palmitoyl chloride, and stearoyl chloride as esterifying agents. Scanning electron microscopy revealed that agarose anhydride modification mostly occurred at the surface of the particles, whereas chloride modification occurred at both the surface and interior of the particles. Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses indicated that hydrophobic groups were successfully introduced in agarose, and the hydroxyl group in the C-2 of D-galactose was the preferred location for esterification. The results also showed that agarose esters with long-chain fatty acids and high substitution degree showed higher emulsifying ability and low interfacial tension property than derivatives with short-chain fatty acids and low substitution degree. Compared with commonly used food emulsifiers, such as Tween, sucrose fatty acid ester, and glycerin monostearate, agarose esters were slightly deficient in emulsifying ability but presented high emulsion stability in oil-in-water emulsion.

Enhancing the performance of perovskite solar cells via interface modification

Interface modification is an effective strategy to improve the performance of perovskite solar cells (PSCs). In this work, edible materials like glycerol and choline chloride were used to modify the surface of hole transport layer (HTL) NiOx. CH3NH3PbI3 (MAPbI3) film fabricated on the modified NiOx has a smoother surface and more uniform grains. It enables an improvement in short-circuit current density (JSC) of PSC from 17.77 ± 0.18 to 20.35 ± 0.36 mA cm−2, leading to an enhancement of power conversion efficiency from 13.37 to 15.25%. The work mechanism of glycerol and choline chloride modification was discussed. Our work provides an efficient and environmentally friendly choice for interface modification.

One-phase synthesis of single enzyme nanoparticles (SENs) of Trametes versicolor laccase by in situ acrylamide polymerisation

Single enzyme nanoparticles (SENs) are a state of art technology that allows immobilisation of individual enzyme molecules in a nanometre scale cross-linked polymer matrix that is covalently bonded to the enzyme. Although the method has great potential in the enzyme immobilisation, it has attracted relatively low attention from researchers over the last decade. Therefore, it can be very fruitful to apply this method to several enzymes in order to increase the understanding about the mechanisms and parameters important for the technique. In this study, Trametes versicolor laccase enzyme (TvL) was immobilised as SENs without phase transfer. The enzyme was immobilised via acryloyl chloride modification that is followed by an in situ polyacrylamide polymerisation in the water phase. The resulting single TvL nanoparticles were found to be less than 50 nm in diameter and round in shape with an activity recovery of 66.33 ± 2.57%. Both Vmax and Km values of the TvL SENs were lower than the free counterpart. However, approximately the same Kcat/Km values suggested similar catalytic efficiencies for the free and the immobilised enzymes. The significantly lower (∼2 fold) Km value of the immobilised enzyme suggested an affinity increase towards 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) upon immobilisation. Whilst the immobilised and the free enzymes showed similar thermal stabilities at 60 °C for 240 min, the immobilised form showed higher stability in solution at ambient temperature after 15 days which may suggest an increase in microbial stability.

Toward understanding the reactivity and catalytic mechanism of coal pyrolysis with metal chloride modification

Catalytic pyrolysis of Zhundong coal over three metal chlorides (NaCl, CaCl2, and FeCl3) was investigated via a thermogravimetric analyzer and a fixed bed reactor in this study. The structural features of the chars were examined using X-ray diffraction, scanning electron microscopy and N2 adsorption analyzer, and the pyrolysis mechanisms regarding the cleavage of bonds were proposed. The results demonstrate that all three chlorides have a beneficial effect on the production of CH4/H2 and are ranked according to catalysis ability as follows: NaCl > FeCl3 > CaCl2; the opposite effect is observed for the production of CO. The addition of metal chlorides results in a highly rough surface and a low degree of graphitization. Moreover, the sample with added FeCl3 has a more porous and disintegrated structure than those with added NaCl and CaCl2, and the pores and cracks are caused by gas release during the transformation process of FeCl3 to Fe2O3. In terms of the catalytic mechanism, FeCl3 differs from NaCl and CaCl2 in coal pyrolysis. FeCl3 is converted to Fe2O3 to promote the formation of free radicals during the pyrolysis process, while Na/Ca species are involved in a repeated process of bond formation and bond breakage between the species and the coal matrix.

The Fast Component of hERG Gating Charge: An Interaction between D411 in the S1 and S4 Residues

Kv11.1 (hERG) is a voltage-gated potassium channel that shows very slow ionic current activation kinetics, and an unusual underlying biphasic gating charge movement with fast and slow components that differ greatly in time course. The structural basis and role of the fast component of gating charge (Qfast) is unclear, and its relationship to the slow activation of hERG channels is not understood. In this study we have used the cut-open oocyte voltage-clamp technique to investigate the relationship of fast gating charge movement-to-residue interactions between D411 at the bottom of the S1, and lower S4 domain charged and uncharged residues. Neutralization of D411 or K538 and V535A prevented Qfast and greatly accelerated overall charge movement. Voltage-clamp fluorometry showed a loss of a fast component of S4 fluorescence in D411N, V535A, and K538Q upon depolarization, whereas [2-(trimethyl ammonium) ethyl] methanethiosulfonate chloride modification of I521C in the outer S4 was enhanced at more negative potentials and at earlier times in these same mutants. A functional interaction between these regions during activation was suggested by ΔΔGo values >4.2 kJ/mol obtained from double mutant cycle analysis. The data indicate that interactions of S1 residue D411 with lower S4 residues stabilizes early closed states of the channel, and that disruption of these interactions results in both faster rates of activation gating and an elimination of the fast component of gating charge movement and of fluorescence. We propose that the Qfast charge movement during activation accompanies transitions through early closed states of the hERG activation pathway, and that the weak voltage dependence of these transitions limits the overall activation rate of hERG channels. Disruption of the D411-S4 interactions destabilizes these early closed states, leaving hERG channels able to activate at a rate similar to conventional potassium channels.

Enhancing the alkaline peroxide mechanical pulp strength by cationization with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride

Alkaline peroxide mechanical pulp (APMP) is a newly emerging high yield pulp (HYP) with numerous advantages. However, the drawback of the alkaline peroxide mechanical pulp from untreated plant biomass is its poor network strength. In this work, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) modification was proposed to enhance pulp network strength by fiber surface modification that could enhance fiber bonding. Three factors were analyzed by response surface methodology (RSM) to optimize treatment conditions based on factorial designs. The results showed that the optimal conditions were CHPTAC dosage of 0.8% (oven-dry pulp), NaOH dosage of 0.1% (oven-dry pulp), and pulp concentration of 8%. The modified pulp fibers were characterized by elemental analysis, charge density analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravity analysis (TGA), and internal bond strength analysis, as well as zero span tensile analysis. The physical strength of the modified APMP pulp was increased in terms of tensile index, tear index, and burst index. After modification, the tensile index, tear index, and burst index increased by 35.3%, 29.2%, and 16.7% respectively. The internal bonding strength increased by 144.4%; however, the increase of zero span tensile index of modified pulp fibers was insignificant.

Preparation of 2-isobutyl-4-methyltetrahydro-2H-pyran-4-ol via Prins cyclization using Fe-modified silica

Prins cyclization of isoprenol and isovaleraldehyde producing 2-isobutyl-4-methyltetrahydro-2H-pyran-4-ol was chosen as a model reaction in iron-modified silica catalysts testing. Two sources of iron were used—iron nitrate and iron chloride. Catalysts were prepared by different procedures and characterized using available methods (XRD, UV/Vis, TPD of pyridine, TGA and XRF). In both types of catalyst, the interaction between the oxygen atoms of silica and the iron atoms of the modifier was confirmed. The iron nitrate-modified catalyst possessed very low acidity enabling only the formation of hemiacetal of isoprenol and isovaleraldehyde or diacetal. The iron chloride modification was performed either by wet impregnation or by impregnation under solvent-free conditions. Both types of such prepared catalysts were active in Prins cyclization, producing the desired substituted tetrahydropyranol. The positive influence of water on the selectivity for the desired compound was confirmed. Siral-type alumosilicates used as support negatively influenced the selectivity. Silica modified by iron chloride may be used as an alternative catalyst in the preparation of substituted tetrahydropyranols; the achieved selectivity was up to 70%.

Original endomorphin-1 analogues exhibit good analgesic effects

A new class of endomorphin-1 analogues was synthesized by combining successful chemical modifications including N-terminal guanidino modification, Phe4 was chlorinated, D-Ala-Gly Substituted L-Pro2. Their bioactivities were measured by radioligand binding assay, metabolic stability and the tail-flick test. In radioligand binding assays, analogue GAGPC (Nα-Amidino-Tyr-D-Ala-Gly-Trp-p-Cl-Phe-NH2), shown a μ-opioid receptor affinity about 1.42-fold higher and a 2.51-fold higher δ-opioid receptor affinity than EM-1. In the metabolic stability assays, GAGPC had the longest half-lives which was 284min and 53-fold higher than that of EM-1. In the tail-flick test in mice, GAGPC chloride modification increases the lipid content of the drug, thus increases the permeability of the blood brain barrier, and has a higher analgesic activity. It might be of importance in potential application as drug candidates as analgesic.

Long-Term Bond Strength of Two Benzalkonium Chloride-Modified Adhesive Systems to Eroded Dentin.

This study investigated the effect of benzalkonium chloride (BAC) modification of two adhesive systems on long-term bond strength to normal and artificially eroded dentin. A total of 128 extracted human molars were sectioned and the buccal and oral surfaces of each molar were ground until the dentin. One half was left untreated (normal dentin) while the other half underwent artificial erosion. Resin composite was bonded to the buccal or oral surface following treatment with Adper Scotchbond 1XT or OptiBond FL without or with 1% BAC incorporation. Shear bond strength (SBS) was measured after 24 h (100% humidity, 37°C) or 1 year (tap water, 37°C). SBS results were statistically analyzed (α = 0.05). SBS was significantly lower to artificially eroded dentin than to normal dentin (p < 0.001). Storage for 1 year had no effect on SBS to normal dentin but led to a significant decrease in SBS to artificially eroded dentin (p < 0.001). BAC incorporation decreased the 24 h SBS to normal dentin (p = 0.018), increased the 24 h SBS to eroded dentin (p = 0.001), and had no effect on the 1-year SBS for either substrate. Consequently, BAC incorporation did not improve bond durability.

Effect of cesium chloride modification on the film morphology and UV-induced stability of planar perovskite solar cells

The interface modification of perovskite thin films has shown great potential to boost the performance of perovskite solar cells during the last few years.