Synergistic Effect Of Surfactants Research Articles

A novel electrochemical sensor for ultra-sensitive detection of nitrite based on the synergistic effect of surfactant and KTiTaO5

A novel electrochemical sensor for ultra-sensitive detection of nitrite based on the synergistic effect of surfactant and KTiTaO5

Interfacial Cooperative Assembly of Surfactants and Opposite Wettability Nanoparticles Stabilizes Water-in-Oil Emulsions at High Temperature.

Pickering emulsions have promising applications in the development of unconventional oil and gas resources. However, the high-temperature environment of the reservoir is not conducive to the stabilization of Pickering emulsions. In addition, the preparation of Pickering emulsions under low-energy emulsification and low-concentration emulsifier conditions is a difficult challenge. Here, we report a high-temperature resistant water-in-paraffin oil Pickering emulsion, which is synergistically stabilized by polyglycerol ester (PGE) and nanoparticles with opposite wettability (lipophilic silica and hydrophilic alumina). This emulsion can be prepared under mild stirring (500 rpm) conditions and can be stable at 140 °C for at least 30 days. The synergistic effects of surfactant, silicon nanoparticles (MSNPs) with different wettability, and alumina nanoparticles (AONPs) on the stability of both emulsions and water-oil interfacial membranes were investigated through bottle experiments, cryogenic scanning electron microscopy (cryo-SEM), optical microscopy, fluorescence microscopy, etc. The results showed that both hydrophobic MSNPs and hydrophilic AONPs are adsorbed together at the water-oil interface to stabilize the W/O emulsion, which can be prepared by 500 rpm stirring. The stability of emulsions strongly depends on the wettability of MSNPs, and the MSNP with moderate hydrophobicity (for example, aqueous phase contact angle of 136°) makes the emulsion exhibit the highest stability against aggregation and settling at elevated temperatures. The emulsion stabilization mechanism was revealed in terms of the adsorption capacity of the surfactant by MSNPs, the adsorption morphology and desorption energy of nanoparticles at the water-oil interface adsorption layer, and emulsion rheology. These findings demonstrate a novel and simple strategy to prepare Pickering W/O emulsions with high-temperature stability at low shear strength.

Synergistic effect of surfactant and silica nanoflowers support on CO2 capture from simulated flue gas by solid amine adsorbents

Solid amine adsorbents were synthesized by functionalizing silica nanoflowers (MSN) with large pore volume using Pluronic P123 (P123) and Polyethyleneimine (PEI) to explore their synergistic effect of CO2 capture. At the optimal loading of 65 wt% PEI and 5 wt% P123, the adsorbent (65PEI/5P123-MSN) displayed peak adsorption performance of 4.12 mmol/g under the dry condition. Notably, the introduction of 3 vol% moisture further increased the adsorption capacity of 65PEI/5P123-MSN to 5.33 mmol/g. Meanwhile, the Avrami kinetic model and the thermodynamic analysis shows that adding P123 reduces adsorption heat (55.89 kJ/mol) and regeneration energy (2.01 GJ/ton) of the adsorbent.

Synergistic effect of surfactants and nanoparticles on the wettability of coal: An experimental and simulation study

Injecting surfactants into coal seams is an effective means to improve coal wettability. Previous studies have shown that nanofluids provided excellent drag reduction and wetting. Therefore, this manuscript investigates the synergies of AOS (Sodium alpha-olefin sulfonate)-modified SiO2 nanofluid on the wettability of coal. Contact angle experiments were performed to examine the effects of deionized water on the wettability of coal treated with different solutions. The results demonstrated that 0.01 wt% nanofluid containing with 0.2 wt% AOS as the significantly increased the wettability. At the micro level, molecular dynamics simulations were employed to analyze the relative concentration distribution and MSD (mean square displacement) of water molecules in different systems. The simulation outcomes revealed that water molecules formed the thickest adsorption layer, and the diffusion range was more expansive, in the H2O/AOS-modified SiO2/Coal system. This was attributed to the amphiphilic structure of AOS-modified SiO2, which bent and folded on the coal surface, where hydrophobic sites were masked and hydrophilic sites were increased. Therefore, water molecules were attracted to the coal, the potential for collision was increased, and the wettability of the coal was enhanced. These findings provide a crucial foundation for modifying nanoparticles with surfactants and using them in coal seam water injection.

The long-term release and particle fracture behaviors of nanoplastics retained in porous media: Effects of surfactants, natural organic matters, antibiotics, and bacteria

The transport of nanoplastics (NPs) in porous media has received a lot of attention, but the studies on the long-term release of NPs retained in porous media and the particle fracture during this process are seriously lacking. For filling this deficiency, we examined the individual or synergistic effects of surfactants, natural organic matters (NOMs), antibiotics, and bacteria on the desorption, long-term release, and particle fracture behaviors of polystyrene NPs (PS-NPs) retained in porous media. It was found that the change in hydrophilicity of PS-NPs dominated the long-term release of PS-NPs retained in porous media when surfactants were present. In the single system of surfactants and the dual system of surfactants and NOMs, the release of PS-NPs were improved owing to the increasing hydrophilicity of PS-NPs, although cationic surfactants also reduced the electrostatic repulsion between PS-NPs and porous media. Increasing antibiotic concentration reduced the electrostatic repulsion between PS-NPs and porous media to inhibit the release of PS-NPs. When bacteria were present whether containing antibiotics or not, the effects on roughness of PS-NPs dominated the release of PS-NPs. The effects of surfactants and NOMs on the PS-NP desorption were similar with the long-term release, with changes in hydrophilicity dominating the process. Whereas the effects of antibiotics and bacteria on the PS-NP desorption were different with the long-term release. Surfactants and NOMs in the presence of surfactants inhibited the fracture of PS-NPs by increasing the hydrophilicity of PS-NPs brought about the coating of water molecules on PS-NPs for protection. Antibiotics had no significant effects on the fracture of PS-NPs due to unaltered vertical forces on PS-NPs and no protective effect. Bacteria in the presence or absence of antibiotics inhibited the fracture of PS-NPs by coating PS-NPs retained in porous media to protect PS-NPs from fracture.

Comparative Assessment of Conventionally and Locally Sourced Surfactants for Enhancing Steam Flooding Techniques for Heavy Oil Recovery in Niger Delta

The recovery of heavy oil reserves presents a significant challenge in the petroleum industry due to its high viscosity and poor mobility characteristics. Steam flooding, as a thermal Enhanced Oil Recovery (EOR) technique, has shown promise in mobilizing heavy oil deposits. However, the limited success of conventional steam flooding in heavy oil reservoirs necessitates innovative approaches. This study explores the utilization of conventional and locally sourced surfactants in surfactant-enhanced steam flooding (SESF) for heavy oil recovery in the Niger Delta region. The study examines the selection, formulation, and injection of surfactants specifically tailored for heavy oil reservoir conditions. Laboratory experiments, core flooding tests, and numerical simulations are conducted to evaluate the impact of surfactants on interfacial tension reduction, wettability alteration, and improved oil mobility in heavy oil reservoirs subjected to steam flooding. The project’s findings demonstrate the significant potential of (SESF) for heavy oil recovery. The synergistic effects of surfactants and steam, including the reduction of oil-water interfacial tension, lead to increased oil production rates, reduced steam consumption, and enhanced sweep efficiency. Furthermore, economic assessments are conducted to evaluate the feasibility of implementing this approach on a field scale, considering both technical and economic aspects. This study not only contributes valuable insights to the field of heavy oil recovery but also underscores the practicality of surfactant-enhanced steam flooding as an environmentally responsible solution for unlocking the vast heavy oil reserves worldwide. The research bridges the gap between laboratory findings and real-world applications, offering a promising path forward for the sustainable development of heavy oil resources.

Synergistic effect of surfactant and 1,10-decanedithiol as corrosion inhibitor for zinc anode in alkaline electrolyte of zinc-air batteries

The self-discharge by corrosion of zinc-air batteries (ZABs) will result in the reduced coulombic efficiency and lower energy efficiency. The additives in electrolyte should not only inhibit the occurrence of self-corrosion during battery dormancy, but also achieve a stable cycle of adsorption–desorption during battery operation, improving the durability of discharge cycles. But the former requires strong binding between additives and zinc to form a dense protective film, while the latter requires easy desorption of additives and zinc without affecting discharge power, which is contradictory to balance. In this study, a dynamic combination of additives and zinc, as well as a design of multi-channel strategy for the corresponding protective layer, have been proposed to solve the issues of self-corrosion and discharge cycle stability. Specifically, the surfactant (octylphenol polyoxyethylene ether phosphate (OP-10P)) and 1,10-decanedithiol (DD) have been selected as the combined anti-corrosion additives in ZABs with concentrated alkaline solution. The synergistic inhibition mechanism and the stabilization mechanism in zinc-air full cells have been studied systematically. The results indicated that the combined inhibitors inhibited the self-corrosion of Zn efficiently in the dormancy, and the inhibition efficiency reached 99.9 % at the optimized proportion. OP-10P achieve the preferential adsorption on the zinc surface, and then the chelates of DD with Zn2+ deposit on the outer layer to form the protective film with fine hydrophobic performance. The stability of ZABs in discharge and charging cycles has been improved owing to the multilayer adsorption film on zinc surface, which retains ion transport channels with the homogeneously pores to weaken the dendrites and side reactions during galvanostatic cycles. A probable model on zinc surface was established to discuss the actual working mechanism.

Synergistic effects of surfactant and polymer on the viscosity and oil displacement efficiency

For chemical flooding, choosing suitable surfactant and polymer mixture to optimize the viscosity and interfacial tension is an important procedure for preparing the combination flooding system. In this work, a systematic study was conducted on the properties of the surfactant/polymer mixed solution, involving viscoelasticity, oil/water interfacial tension and oil displacement efficiency. Zwitterionic-anionic surfactant mixture (HDPS-SDS) was chosen to show the effect of concentration and micelles type. Partially hydrolyzed polyacrylamide (HPAM) and hydrophobically associating polymer (HPOC) were selected to show the effect of polymer concentration and type. It has been found that for polymer solutions, adding HDPS-SDS reduces the oil/water interfacial tensions to the magnitude of 10−2 mN·m−1, but negative synergistic effect for spherical micelles and positive synergistic effect for wormlike micelles on viscosity are observed. For wormlike micelles solutions, adding HPAM or HPOC increases the viscosity. Moreover, the positive synergistic effect on viscosity by HPOC is far stronger than that of HPAM, and the viscosity of wormlike micelle solution can be reinforced by adding a small amount of HPOC. The synergistic effect on viscosity will also affect the oil displacement efficiency of the surfactant/polymer mixed system. For example, the enhanced oil displacement efficiency E of surfactant/polymer flooding unexpectedly reduces with adding spherical micelles formed by low concentration HDPS-SDS to 1500 mg L−1 HPOC solutions. Whereas the enhanced oil displacement efficiency E of wormlike micelles/polymer flooding reaches 28.8% with adding 800 mg L−1 HPOC to 5500 mg L−1 HDPS-SDS wormlike micelles solutions.

Ultra-Low-Density Drilling Fluids for Low-Pressure Coefficient Formations: Synergistic Effects of Surfactants and Hollow Glass Microspheres

With the increase in drilling fluid density requirements in low-pressure coefficient formations, traditional hollow bead drilling fluids and foam drilling fluids each have different degrees of deficiencies. Through extensive indoor experiments, an amphoteric surfactant (cocoamidopropyl betaine) with better foaming performance was selected to formulate an ultra-low-density drilling fluid that combines a foaming agent and hollow glass microbeads to reduce the density of the fluid, with the following specific formulation: 3% bentonite slurry + 0.3% xanthan gum + 0.5% carboxymethyl cellulose + 0.5% starch + 2% lignite resin + 2% blocking agent + 4% hollow glass microspheres + 0.5% foaming agent + 2% nano blocking agent. The performance of the system was evaluated, and the results showed that: the density of the ultra-low-density drilling fluid did not change much before and after aging at 80 °C and was relatively stable; the filter loss amount of the drilling fluid (tested by API) reached 4.6 mL, which meets the requirements for filter loss of drilling fluid; it can bear the pressure of 12 MPa under a 60–90-mesh sand bed and has better pressure sealing capability than hollow glass microbead drilling fluid.

The Synergistic Effect of Surfactants and Plant Oils on the Effectiveness of Levo to Control the Fourth Phase Larvae of the Great Wax Moth Galleria Mellonella L. (Lepidoptera: Pyralidae)

The laboratory study aimed to know effect three surfactants (Inex-A, Stickon, Wetfix) and plant oils Includes Bitter apple oil Citrullus colocynthis, and Rosemary oil Rosmarinus officinalis on effectiveness five concentrations ppm ((30,40,50,60,70) for commercial pesticide plant origin Levo2.4SL (Oxymatrine) on fourth phase larvae to Great Wax Moth G.mellonella. The results showed that were significant differences in mortality percentage to fourth phase larvae of Great Wax Moth worm by the effects Levo pesticide on larvae, as (Levo + rosemary oil) treatment excelled in achieving highest larval mortality percentage 84%, followed by (Levo + bitter apple oil) treatment, with an average mortality percentage was 72%. while mortality percentage in (Steckon + Levo) and (wetfix + Levo) treatments was 70, 67.33, respectively. Levo pesticide efficacy decreased in (Inex + Levo) treatment to 38% compared with mortality percentage in before addition treatment to Levo pesticide, which amounted to 63.33%.

Effect of nanoparticles and nanosheets on improving the oil/water interface performance of surfactants in enhancing oil recovery: A comparative study by molecular simulation

In recent years, nanoparticles have become the most potential enhanced oil recovery technology because of their unique small size effect and specific surface area effect. With the research and application of graphene and its derivative materials, nanosheets are one of the research hotspots of nanomaterials for enhanced surfactant flooding. However, as far as we know, the molecular simulation comparison of nanoparticles and nanosheets to enhance the performance of surfactants has not been reported so far. Therefore, in this paper, we constructed nano-SiO2 particles grafted with hydroxyl and pentyl alkane activator, graphene nanosheets grafted with carboxylic acid chain and pentyl alkane activator for the first time. On this basis, the interfacial tension, interfacial density, interfacial generation energy and radial distribution function were analyzed by molecular dynamics simulation. The results show that nanoparticles and nanosheets have synergistic effect with amphoteric surfactant dodecyl dimethyl aminoethyl lactone (BS-12). The synergistic effect of nanosheets and BS-12 was stronger after carboxylic acid chain and pentyl alkane activator are grafted on the surface of nanosheets. The interfacial tension of n-dodecane/water could be reduced to 13.58 mN/m after the modified nanosheets are compounded with BS-12. The interfacial tension of n-dodecane/water could be reduced to 4.15 mN/m by the modified nanosheets are compounded with BS-12, and the ability of reducing the interfacial tension between oil and water is significantly improved. The calculation of n-dodecane/water interface thickness and interface formation energy showed that compared with the modified nanoparticles and BS-12 compound system, the interface thickness of the modified nanosheets and BS-12 compound system increased by 9.24%, and the interface formation energy increased by 17.85%. In addition, the results of radial distribution function analysis also demonstrated that the modified nanosheets had strong hydration with water molecules after being compounded with BS-12. The results of this work can provide new ideas for further research on the synergistic effect of surfactants and nanomaterials, as well as the development of oil displacement technology based on surfactants/nanomaterials.

Synergistic Effect of Surfactant on Disperser Energy and Liquefaction Potential of Macroalgae (Ulva intestinalis) for Biofuel Production

The objective of this study was to evaluate the effect of surfactant on disperser homogenization pretreatment for macroalgae (Ulva intestinalis) to enhance biogas production. The macroalgae are subjected to surfactant coupled disperser pretreatment, which enhanced the liquefaction and improved the biomethane production. The outcome of this study revealed that 10,000 rpm at 20 min with a specific energy input of 1748.352 kJ/ kg total solids (TS) are the optimum conditions for surfactant disperser pretreatment (SDP), which resulted in the liquefaction rate of 20.08% with soluble organics release of 1215 mg/L and showed a better result than disperser pretreatment (DP) with a liquefaction rate of 14%. Biomethane production through the SDP method was found to be 0.2 g chemical oxygen demand (COD)/g COD, which was higher than DP (0.11 g COD/g COD). SDP was identified to be a synergetic pretreatment method with an energy ratio and net profit of about 0.91 and 104.04 United States dollars (USD)/ton, respectively.

Synergistic effect of surfactants in porous geopolymer: Tailoring pore size and pore connectivity

With the growing interest in foamed geopolymer manufacture, there is an increasing demand for tailoring these composites’ pore structure. The binary system of two surfactants offers a possibility for enhancing foam formation efficiency and stability in geopolymer paste, however, their effects are not well understood. The influence of binary system blends on pore formation, size, and distribution in fly ash-based geopolymer matrix is investigated and their synergistic effects are evaluated. The results show that combining a nonionic surfactant with anionic Sodium Dodecyl Sulfate (SDS) increases open porosity, whereas cationic Cetyltrimethylammonium Bromide (CTAB) promotes the development of closed pores, improving thermal insulating, hygrothermal and mechanical performance. Moreover, this paper proposes a mechanism to describe the creation of pores in the presence of mixed micelles, as well as the benefit of employing mixed surfactant systems in customizing porous composites.

Experimental investigation of silica nanoparticle assisted Surfactant and polymer systems for enhanced oil recovery

Enhanced oil recovery techniques are commonly used today in oil fields to boost oil production. The objective of the present study is to investigate the use of silica nanoparticles (NPs) with surfactants and polymers to increase the oil recovery from oil fields. Synergistic effects of surfactant, polymer, and nanoparticles on interfacial tension (IFT) reduction, wettability alteration, emulsification, and viscosity improvement are reported in this study. Core flooding experiments were performed in cores with different permeabilities to screen the reservoir on basis of rock properties. The dispersion of NPs in the aqueous solution of surfactant and polymer was characterized by stability analysis, Turbiscan analysis, dynamic light scattering (DLS), and zeta-potential measurements. The nanoparticles were able to further reduce the IFT between the surfactant solution and crude oil. The stability of nanofluids was increased when surfactant was added as evidenced by a higher zeta potential value (−39.6 mV). The addition of polymer led to even higher stability of the nanofluids as observed by the Turbiscan analyzer. A synergistic effect of NPs, surfactant, and polymer was observed in the core flooding experiments. The nanofluid system provided higher incremental oil recovery in high permeability core as compared to low permeability core. Different recovery mechanisms responsible for oil recovery by nanofluids like wettability alteration, disjoining pressure, log jamming, and pore channel plugging phenomena are discussed. The flooding results indicate that the injection of the designed slug increases the oil recovery up to 28% of the original oil in place after conventional water flooding. Therefore, the findings of this study can help for a better understanding of the use of silica NPs with surfactant and polymer as a chemical EOR agent. The result also helps in the screening of sandstone reservoirs where nanofluid could be employed.

Synergism between lipophilic surfactant and lipophilic SiO2 nanoparticles enhances self-emulsification performance

Water control technology for high-temperature and -salinity gas wells is immature, and there is a lack of effective water control methods for condensate gas reservoirs and horizontal wells. Water control can be achieved by conducting subsurface self-emulsification to generate nanoparticle emulsions (Pickering emulsions). While this has been tested in oilfields, the overall success rate is low. Elucidating the mechanism of nanoparticle and surfactant synergy would help to improve the success rate of using self-emulsifying water-in-oil (W/O) Pickering emulsions for water control in gas wells. In this study, a self-emulsification process was simulated based on the formation conditions of the Tahe gas well using an active oil (diesel containing 1 wt% non-ionic surfactant) containing various concentrations of nanoparticles. By measuring the droplet size, viscosity, viscoelasticity and high-temperature stability of the emulsion, and in combination with previous research results, the synergistic effects of nanoparticles and surfactant on the generation and stability of emulsions were clarified. Finally, we explored the conditions under which synergy at the oil-water interface occurs and whether the nanoparticle surfaces were secondarily modified under formation conditions. The strength of the synergistic effect in the self-emulsifying system was found to be strongest at a 1:1 nanoparticle-to-surfactant concentration ratio. The strength of the synergistic effect was proportional to the emulsion's volume, droplet size, viscosity, viscoelasticity and other properties. The most synergistic self-emulsifying emulsion had up to five times the volume of emulsions made at other oil-to-water ratios. The emulsion droplet size showed a bimodal distribution, with mean particle sizes of 3 μm and 100 μm, respectively. The viscosity of the emulsion generated at 80 °C reached 2000 mPa s−1 at room temperature (26 °C) and increased to 2500 mPa s−1 as the temperature increased to 80 °C. Viscoelastic tests at 80 °C show that the emulsion generated at a concentration ratio of 1:1 exhibited the greatest and most stable elastic properties and that agglomerations of emulsion plugging pore throats were not easily penetrated by subsurface fluids. At this point, the nanoparticles were uniformly distributed at the droplet interface and the particle surfaces remained unchanged. The mechanism by which the synergistic effect stabilizes the emulsion changed at high temperatures (140 °C). The nanoparticles at the interface were wrapped in a thick oil film of high viscosity, like the inner phase of an emulsion. Then, concave high-viscosity oil-phase channels were formed between the ‘emulsified-like nanoparticles’. This change at the oil-water interface ensured the stability of the W/O emulsion at high temperatures. The synergy between the surfactant and nanoparticles was primarily based on the formation of an emulsion at the oil-water interface by the surfactant, followed by the gradual adsorption of nanoparticles at the interface, which enhanced the emulsion properties. The nanoparticle interface did not undergo secondary modification under formation conditions, and the synergistic effect of the surfactant and nanoparticles remained dominated by electrostatic forces.

Synthesis and electromagnetic properties of NH2-MIL-88B(Fe) crystals with morphology and size controllable through synergistic effects of surfactant and water

Synthesis and electromagnetic properties of NH2-MIL-88B(Fe) crystals with morphology and size controllable through synergistic effects of surfactant and water

Synergistic effect of surfactant and chlorine salt on dispersion of nano-SiO2 and performance of cement-based grout containing a large amount of bentonite

Nano-SiO2 (NS) is widely used to improve the performance of cement-based grouts. The workability and mechanical property of grouts are greatly affected by NS dispersion. In this paper, synergistic effect of surfactants and chloride salts on NS dispersion, as well as on performance of grouts including fluidity, mechanical and microscopic properties were systemically studied. The results showed that the synergistic effect of anionic surfactant (SDS) and chloride salt can effectively improve NS dispersion because of the massive formation of micelles that can encapsulate NS and the electrostatic repulsion between micelles. And the effect of CaCl2 was more significant than NaCl. Furthermore, fluidity of fresh slurry and mechanical property of hardened grouts were also improved by the synergistic effect. The mechanical property enhancement might be attributed to the filling effect of NS due to its improved dispersion, and to the matrix compaction associated with the formation of strätlingite and Friedel's salt.

Control of the Micro-Defects on the Surface of Silicon Wafer in Chemical Mechanical Polishing

The final polishing of silicon results in the irresistible formation of micro-defects (i.e., particle residues and scratches) on the surface. In view of this problem, the synergistic effect of surfactants and water-soluble polymers in inhibiting the micro-defects on the silicon surface was studied in this paper to improve the wettability of the slurry and reduce the micro-flocculation of abrasive particles. The results showed that the total number of residual particles (≥0.06 μm) on the polished surface was reduced from 24,784 to 277 with the adsorption of cationic polyacrylamide (CPAM) and fatty alcohol polyoxyethylene ether (AEO-9). The water-soluble polyvinylpyrrolidone (PVP) polymer could coat on the SiO2 abrasives, inhibit the flocculation of abrasive particles, avoid scratches on the silicon surface and further reduce the number of residual particles (≥0.06 μm) to 67 on the polished surface. Furthermore, a contact angle analyzer was used to characterize the wettability of the components in the slurry, and a large particle counter was used to analyze the changes in the number of large particles in the slurry component. Finally, a mechanism of surfactants and a water-soluble polymer combined system was proposed to suppress the micro-defects on the surface of the silicon wafer.

Preparation and performance of a biological dust suppressant based on the synergistic effect of enzyme-induced carbonate precipitation and surfactant.

To control the dust pollution caused by open-pit coal mining and reduce or avoid the secondary hazards of existing dust suppressants to the environment, a biological dust suppressant was prepared through the synergistic effect of a surfactant and an enzyme-induced carbonate precipitation. The optimal ratio of biological dust suppressant was determined, and the dust suppressive effect and dust consolidation mechanism of the biological dust suppressant were investigated. The results showed that the optimal biological dust suppressant had an alkyl polyglycoside (APG) concentration of 0.3 wt.%, a urea-CaCl2 concentration of 0.6 mol/L, and a urease to urea-CaCl2 volume ratio of 1:3. The wind erosion resistance of coal dust treated with this dust suppressant was enhanced by 86.69%. The adsorption of the biological dust suppressant by coal dust was mainly due to the electrostatic interaction between the surfactant and coal dust. The mineralization product of the dust suppressant was calcite-type CaCO3, which consolidated coal dust due to the formation of intermolecular hydrogen bonds between CaCO3 and coal dust.

Synergistic effect of surfactant and saccharin on dispersion and crystal refinement for electrodeposition of nanocrystalline nickel/graphene oxide composite

Homogeneous dispersion of graphene oxide (GO) in nickel sulfamate solution is a significant challenge for electrodepositing high-performance nickel/GO composite coatings. In the present work, three typical surfactants, including anionic surfactant Sodium dodecyl sulfate (SDS), cationic surfactant Cetyltrimethylammonium bromide (CTAB), and non-ionic surfactant Polyethylene glycol (PEG), and saccharin are used to disperse GO nanoparticles and refine crystallite size of nickel/GO composite coating. The synergistic effect of surfactant and saccharin is revealed from the perspectives of dispersion, crystal refinement and their impact on mechanical and tribological properties of nickel/GO composite coating. Our results indicate that PEG possesses the optimal dispersibility to GO dispersion, followed by CTAB and SDS. The addition of saccharin in electrolyte does not affect the surface charge of GO particles, but it helps to reduce the particle size of GO and thus reduce potential reaggregation. Additionally, PEG shows the most significant reduction of crystallite size from ~35 nm to ~19 nm. The synergetic effect of surfactant and saccharin is indicated by increasing the concentration of saccharin from 0 to 0.2 g/L with various surfactants, where the overall crystallite size is gradually reduced. Moreover, the hardness of PEG-GO and CTAB-GO coatings is remarkably increased by 252% and 312%, respectively, compared to pure nickel coating. The increased hardness is due to the synergistic effect of crystal refinement from both additions of GO and saccharin. The tribological test indicates that the PEG-GO coating can achieve the maximum reduction of friction coefficient with 0.15 with the addition of saccharin of 0.2 g/L.