Organic Surfactants Research Articles

Revolutionizing applications: the impact of controlled surface chemistry on marble powder.

A large amount of marble powder is abundantly available as a byproduct and waste in the marble industry, and its reinforcement has been attempted in several applications through surface modification. This article examines the use of MP in the production of rubber, paper, foam stabilizers, asphalt, paint, textiles, and adhesives. This article aims to provide a foundation for the surface modification of MP to enhance its properties and broaden its range of applications. Data on modifiers such as organic acids, coupling agents, polymers, and surfactants have been gathered, along with comprehensive reaction details for various techniques, including wet modification, dry modification, in situ modification, ultrasonication, and sol-gel methods. A general overview of MP modification and its impact on composite properties is provided in this review paper, mainly focusing on the distinctive features of composites, contemporary field challenges, and the correlation between the properties and applications of MP.

Construction of multi-functional silicone rubber/reduced graphene oxide/multi-walled carbon nanotube composites with segregated structure by surfactant-free Pickering emulsion method

Polymer composites with segregated structure (PC–S) have the advantages of low filler usage and excellent functionality. Emulsion blending combined with direct molding technology is the main method for the preparation of PC-S. However, due to the high fluidity of low-viscosity silicone rubber (SR), PC-S cannot be prepared by this technique. In addition, surfactants affect the heat resistance of the final SR composites (SRC). In order to solve the above problems, in this study, a Pickering emulsification combined with pre-crosslinking technology for SR was successfully developed by using graphene oxides (GO)/multi-walled carbon nanotubes (MWCNTs) hybrid fillers (GM) as emulsifiers, and SR/reduced GO (RGO)/MWCNTs composites with segregated structure (SSGM) were prepared. When RGO content is 4.5 wt%, MWCNTs content is 3.2 wt%, SSGM shows the highest electrical conductivity of 12.5 S/m, the highest electromagnetic interference shielding efficiency (EMI SE) of 41.4 dB, and an excellent flame retardant performance. The whole preparation process avoids the use of organic solvents and surfactants, which reduces the production cost of SSGM and the environmental pollution, and provides a feasible preparation route for the industrialized production of SSGM.

Fabrication of hydrogel mini-capsules as carrier systems

Conventional drug administration often results in systemic action, thus needing high dosages and leading to potentially pronounced side effects. Targeted delivery, employing carriers like nanoparticles, aims to release drugs at a target site, but only a small fraction of nanoparticles actually reaches it. Microrobots have been proposed to overcome this issue since they can be guided to hard-to-reach sites and locally deliver payloads. To enhance their functionality, we propose microrobots made as deformable capsules with hydrogel shells and aqueous cores, having the potential added advantages of biocompatibility, permeability, and stimulus-responsiveness. Endowing microrobots with deformability could allow them to navigate inside capillaries and cross barriers to finally reach the target site. In this study, we present a cost-effective method for fabricating core-shell structures without the use of organic solvents, surfactants, or extreme pH conditions unlike other techniques (e.g. Layer by Layer). The process begins with the dripping of a mixture of hydrogels, agarose and alginate, into a solution to gelate the drops into beads. After they are loaded with calcium ions at different concentrations, they are immersed in an alginate solution to form the shell. Finally, the beads are heated to let the agarose melt and diffuse out, leaving a liquid core. By varying the concentration of calcium ions, we obtain shells of different thicknesses. To estimate it, we have developed a method using the colour intensity from microscope images. This allowed us to observe that lowering the calcium ions concentration below a threshold does not lead to the formation of continuous shells. For higher concentrations, although the core may remain partially gelled, continuous shells successfully form. Therefore, our fabrication process could find applications in drug delivery, encapsulation systems, and microrobotics.

Hydrophobicity of Benzene-Based Surfactants and Its Effect on Bubble Coalescence Inhibition.

Bubble coalescence plays a critical role in optimizing biological and industrial processes, impacting efficiency in areas such as fermentation, wastewater treatment, and foaming control. While the relationship between chemical structure and bubble coalescence has been thoroughly explored for inorganic ions, limited data exist on organic ions and surfactants, despite their widespread use in these industries. This study addresses this gap by investigating the effects of surfactant hydrophobicity and bubble size on coalescence behavior at a flat air-liquid interface and within a bubble column. Surface tension measurements were employed to assess surfactant hydrophobicity, while bubble size and coalescence time were analyzed to determine their respective influences. The results reveal a novel quantitative relationship between surfactant hydrophobicity and the half-coalescence inhibition concentration (HCIC), a new variable introduced in this study. This relationship demonstrates that as hydrophobicity increases, the HCIC also rises, providing a new relationship between surfactant hydrophobicity and bubble coalescence. While it is well-known that more hydrophobic molecules delay coalescence, this is the first time a direct, proportional relationship has been established with HCIC, offering a new parameter for predicting and controlling coalescence phenomena.

Enhancing Greywater Treatment: High-Efficiency Constructed Wetlands with Seashell and Ceramic Brick Substrates

Constructed wetland (CW) systems have been recognized as a sustainable technology for wastewater treatment that can be easily integrated into the local natural environment, offering both low cost and high efficiency. In this study, synthetic greywater was treated using a vertical subsurface flow CW operated in batch mode with 7-day cycles across two phases, operated in parallel: I, non-vegetated, and II, vegetated, with Echinodorus subalatus. The mixed filter bed was composed of seashells, ceramic brick fragments, and sand. No statistically significant differences (p > 0.05) were observed between the non-vegetated and vegetated phases for most parameters. The removal efficiencies of organic matter, anionic surfactants, and total phosphorus in the non-vegetated versus vegetated phases were (91.0 ± 3.8)% versus (94.0 ± 1.1)%; (71.9 ± 14.1)% versus (60.0 ± 9.5)%; and (35.2 ± 4.6)% versus (40.2 ± 15.5)%, respectively. Phosphorus removal exceeded values reported in the literature for both phases, primarily due to the calcium present in the seashells, which increased the electrical conductivity and hardness of the effluent compared to the influent. The macrophyte exhibited leaf desiccation, possibly due to contact with greywater and its young age (30 days), which may have negatively impacted the system’s performance during the vegetated phase.

Proniosomes Nanoparticle for the Treatment of Peripheral Arterial Disease.

The common symptom of systemic atherosclerosis is peripheral arterial disease (PAD), which occurs when the artery lumen in the lower extremities gradually becomes blocked by atherosclerotic plaque. The most frequent symptom of lower extremity PAD, called "vascular claudication," which is pain experienced when walking. Partial or total blockage of the peripheral arteries in the upper and lower limbs is called PAD. The danger of death from concurrent coronary artery and cerebrovascular atherosclerosis outweighs the risk of amputation. However, niosomes have issues with fusion, aggregation, leakage, vesicle sedimentation, and difficulty in sterilizing. A more recent strategy known as pro-vesicular carriers was used to solve these issues. The formulations in Proniosomes are dry and anhydrous, protected with a non-ionic surfactant that serves as a carrier when combined with water. Formulation prepared by organic solvent, surfactant, cholesterol, other components and hydration medium. Coacervation Phase separation Technique used for proniosome Nanoparticle. Box Bhenken Design is used for optimization batches. In this context, we shall discuss the development of Proniosome for the treatment of peripheral arterial diseases. From here, we know that proniosome nanoparticles is pro vesicular system good characteristics and effectiveness for treating peripheral arterial diseases. Proniosomes may be created using various techniques, which may impact how they develop along with the drug's characteristics. They increase the drug's stability while being delivered while being entrapped. They don't need particular conditions for handling, protection, storage, or industrial manufacturing.

Comparative study of greywater treatment using activated carbon and woodchip biochar for surfactant and organic matter removal

Greywater (GW) treatment is recognized as a more efficient alternative to blackwater treatment, particularly for reuse applications, due to its lower pathogen content and higher concentrations of chemical oxygen demand (COD) and surfactants. In this study, the adsorption performance of woodchip biochar (BC) and activated carbon (AC) was compared for the removal of COD, anionic surfactants (ASU), and non-ionic surfactants (NISU) from GW. Response Surface Methodology (RSM) was employed to optimize the removal efficiency of both organic matter and surfactants. AC demonstrated higher adsorption capacities for COD and ASU, with KL = 0.007 L/mg and Qmax = 0.95 mg/g for COD, and KL = 1.4 × 104 L/mg and Qmax = 0.08 mg/g for ASU. In contrast, BC showed a significantly higher affinity for NISU, with KL = 8.4 × 103 L/mg and Qmax = 0.01 mg/g. Breakthrough curves and pseudo-first-order (PFO) kinetics provided insights into adsorption dynamics, with AC showing delayed breakthrough and greater longevity, while BC offered rapid adsorption and cost-effectiveness. The treated GW achieved substantial reductions in contaminant levels, with final COD and surfactant concentrations reduced to approximately 10 mg/L and 0.05 mg/L, respectively, meeting Italian and Australian regulatory standards. The study highlights the potential of woodchip BC as a cost-effective and sustainable alternative to AC, particularly for short-term adsorption applications, and offers valuable insights into the treatment of GW for reuse.

Electropolymerized InZnSe@PtAg quantum dots@molecularly imprinted polymer on screen-printed carbon electrodes for the ultrasensitive detection of NS1 dengue virus protein with smartphone-based sensing in saliva

According to the World Health Organization (WHO), an estimated 100–400 million cases of dengue virus (DENV) infections are recorded annually with half of the global population being at risk of infection. Currently, there is no known treatment for DENV; however, early, rapid and accurate (sensitive and selective) detection can help to alleviate fatality rates. This work reports on the novel development of a point-of-care electrochemical biosensor for DENV using nanostructured InZnSe@PtAg quantum dots (QDs)-molecularly imprinted polymer (MIP) with smartphone-based detection functionality. Highly conductive InZnSe@PtAg QDs were newly synthesized in the presence of metal precursors, organic surfactants and ligands and surface capped with glutathione (GSH) using a ligand exchange reaction. PtAg was used as an electroactive shell layer on the InZnSe QDs core surface to increase the QDs conductivity. The GSH-InZnSe@PtAg QDs were drop-casted onto screen-printed carbon electrodes (SPCEs) and electropolymerized using cyclic voltammetry (CV) in the presence of o-phenylenediamine and the template DENV. The robust electropolymerization process allowed the overcoating of the MIP layer on the QDs/SPCE, where specific DENV size and shape cavities were created. Under optimal experimental conditions, DENV was rapidly, selectively and ultra-sensitively detected. Using differential pulse voltammetry (DPV), quantitative rebinding of DENV on the MIP@QDs/SPCE surface led to a steady decrease of the anodic peak current and a limit of detection of 1.36 pg/mL was obtained for DENV detection. Using a hand-held smartphone-based potentiostat, DENV was successfully detected in human saliva with satisfactory analytic recoveries.

Customizable OpenGUS immunoassay: A homogeneous detection system using β-glucuronidase switch and label-free antibody

We developed a customizable OpenGUS immunoassay that enables rapid and sensitive detection of analytes without requiring antibody modification. This immunoassay employs label-free whole antibodies, an antibody-binding Z domain (ZD) derived from Staphylococcal protein A, and a β-glucuronidase (GUS) switch mutant, allowing for easy replacement of antibodies to tailor the immunoassays for various targeted antigens. The working principle is that the OpenGUS probe, the fusion protein of ZD and a GUS switch, converts the antibody-antigen interaction into GUS activation in a one-pot reaction. To enhance the signal-to-background ratio of the immunoassay, a GUS switch mutant that exhibits reduced background activation was developed by screening several additional mutations at the diagonal interface residue H514. Moreover, we optimized the composition of the reaction buffer, including organic solvents, salt, and surfactant. Under optimal conditions, we customized OpenGUS immunoassays for Cry j 1, human C-reactive protein, and human lactoferrin, achieving around 10–20-fold maximum fluorescence (15 min) or colorimetric (2 h) responses with picomolar to low nanomolar level detection limit, simply by using commercially available IgGs. Additionally, the three analytes were successfully detected in complex matrices similar to those used in practical applications. We believe that this customizable OpenGUS immunoassay will pave the way for the prompt development of rapid and sensitive homogeneous immunoassays for point-of-care diagnostics, high-throughput testing, and onsite environmental assessments.

Pseudocapacitive and Magnetic Properties of SrFe12O19–Polypyrrole Composites

This study is inspired by the importance of advanced composites, combining spontaneous magnetization with electrical charge storage properties. It is focused on the investigation of magnetically hard SrFe12O19 (SFO) material and its composites with polypyrrole (PPy). For the first time, an organic surfactant–charge transfer mediator and high-energy ball milling (HEBM) were applied to the preparation of high-active-mass SFO composite electrodes. An important finding was the ability to achieve enhanced capacitance of SFO and its composites in a negative range of electrode potentials in an electrolyte. The benefits of the sodium sulfate electrolyte and the charge storage mechanism are discussed. Another important finding was the synergy of the properties of SFO and PPy, which allowed the preparation of highly capacitive conductive composites. The effects of HEBM and the SFO content in the composites on the capacitive properties were studied. Magnetic measurements revealed the effect of HEBM on the magnetic properties and demonstrated good magnetic properties of the composites, which also exhibited advanced capacitive properties. The composites were utilized for the manufacturing of an asymmetric device, which exhibited high capacitive properties at an applied voltage of 1.5 V.

Cloning, Expression, and Characterization of a Metalloprotease from Thermophilic Bacterium Streptomyces thermovulgaris.

Proteases hydrolyze proteins and reduce them to smaller peptides or amino acids. Besides many biological processes, proteases play a crucial in different industrial applications. A 792 bp protease gene (nprB) from the thermophilic bacterium Streptomyces thermovulgaris was cloned and expressed in E. coli BL21 using pET 50b (+). Optimal recombinant protease expression was observed at 1 mM IPTG, 37 °C for 4 h. The resulting protease was observed in soluble form. The molecular mass estimated by SDS-PAGE and Western blot analysis of the protease (NprB) fused with His and Nus tag is ~70 KDa. The protease protein was purified by Ammonium sulfate precipitation and immobilized metal ion affinity chromatography. The optimum pH and temperature for protease activity using casein as substrate were 7.2 and 70 °C, respectively. The mature protease was active and retained 80% of its activity in a broad spectrum of pH 6-8 after 4 h of incubation. Also, the half-life of the protease at 70 °C was 4 h. EDTA (5 mM) completely inhibited the enzyme, proving the isolated protease was a metalloprotease. NprB activity was enhanced in the presence of Zn2+, Mn2+, Fe2+ and Ca2+, while Hg2+ and Ni2+ decreased its activity. Exposure to organic solvents did not affect the protease activity. The recombinant protease was stable in the presence of 10% organic solvents and surfactants. Further characterization showed that zinc-metalloprotease is promising for the detergent, laundry, leather, and pharmaceutical industries.

Surface populations as a model for the distance-dependence of the interfacial refractive index.

Vibrational sum frequency spectra provide information about interfaces that is sensitive to the orientation of molecules, their electronic environment, and the local electric fields. Here, we use molecular dynamics simulations in order to study a surfactant, para-cyanophenol, at the air-water interface. The volume fractions of water and the organic surfactant are considered at various points over the nanometer-scale region in a Lorentz-Lorenz model. We find that the calculated ratios of nonlinear susceptibility tensor elements are in agreement with experimental data only when this depth profile was considered. We also use these data to evaluate the ratio of the C-N hyperpolarizability tensor elements in the interfacial region.

Organic acid preservation of cereal grains improves grain quality, growth performance, and intestinal health of post-weaned pigs

This study investigated the effect of preserving wheat and barley grains with an organic acid liquid surfactant mould inhibitor compared to conventional artificial drying and assessed its effects on the health and performance of pigs post-weaning (PW). A 2 × 2 factorial arrangement was conducted to investigate the interaction between grain preservation method (dried vs. preserved) and zinc oxide (ZnO) inclusion (yes vs. no) on growth performance, diarrhoea scores and incidence, and total tract nutrient digestibility. One hundred and ninety-two pigs (3 pigs/pen; 16 replicates/treatment) were assigned to one of four experimental diets for 35 days: (1) dried grain diet, (2) preserved grain diet, (3) dried grain diet with ZnO and (4) preserved grain diet with ZnO. Diets were formulated to contain similar levels of net energy and standardised ileal digestible lysine. On day 35 PW, 24 pigs (12 replicates/treatment) from the non-ZnO supplemented groups were euthanised and digesta was collected for coefficient of apparent ileal digestibility (CAID), gut microbial population and volatile fatty acid analysis. Stomach tissue was also collected for gene expression analysis, as well as small intestine samples for gut morphology. Notable improvements in grain quality were observed in the preserved grain, including a reduction in grain pH, mould presence, and contamination by mycotoxins, specifically deoxynivalenol in wheat and barley, and ochratoxin A and HT-2 toxin in barley. The preserved grain diet improved average daily gain (ADG; P < 0.01) and body weight (BW; P < 0.01) compared to the dried grain diet. The incorporation of ZnO increased average daily feed intake (ADFI; P < 0.01) and BW (P < 0.05) in the dried grain diet, however, ZnO did not affect ADFI (P > 0.05), and reduced ADG and BW in the preserved grain diet (P < 0.05). Pigs offered the preserved grain diet had reduced faecal scores and diarrhoea incidence compared to those offered the dried grain diet (P < 0.05). Supplementation of ZnO reduced faecal scores and diarrhoea incidence compared to non-supplemented pigs (P < 0.001). On day 35 PW, the preserved grain diet had improved CAID of nitrogen and gross energy (P < 0.05), lower levels of colonic branched-chain volatile fatty acids (P < 0.05), and beneficial shifts in gut microbial populations. Specifically, there was a reduction in ileal Streptococcus (P < 0.001) and an increased abundance of colonic Faecalibacterium (P < 0.05). In conclusion, organic acid preservation improved grain quality, benefiting post-weaned pigs through improved nutrient digestibility and gut health, thus enhancing overall growth performance PW.

The failure mechanism of field polyethylene gas pipeline with gas leakage at electrofusion joint

PurposeA section of in-service PE gas pipeline in Guocun, Beijing, was found to appear gas leaking at the electrofusion (EF) joint. This study is dedicated to reveal the material cause of EF joint failure to help with a more accurate prediction of service life of PE gas pipe and further normalize the construction of PE gas pipeline.Design/methodology/approachDefect detection was carried out on the leaking EF joint using ultrasonic phased array. The mechanical degradation and structural aging behavior was studied by tension test, FTIR technology, TG test and DSC test. The organic components in the soil surrounding the PE gas pipe failure area were qualitatively identified.FindingsThe results showed that the organic surfactants in the soil environment could accelerate the aging behavior of PE material, leading to a deterioration of mechanical properties and a serious reduction in the ability of the PE pipe and EF joint, especially at the welding defect, to resist external force.Originality/valueA novel study was conducted to investigate the failure cause of the EF joint of in-service PE gas pipe, incorporating the analysis of environmental factors and structural deterioration.

Liquid-solid interface polymerization: A simple approach for efficient polyamide/polyethylene thin film composite total heat exchange membranes construction

A simple liquid-solid interface polymerization (LSIP) strategy was developed to prepare high performance polyamide (PA) based thin film composite (TFC) total heat exchange membranes (THEMs) to avoid the use of organic solvents and surfactant during the inverse phase interface polymerization processes between piperazine (PIP) and 1,3,5-benzenetricarbonyl trichloride (TMC) on porous polyethylene (PE) substrates. The non-polar organic solvent in the TMC organic phase coated on the surface of the PE surfaces was completely removed beforehand by evaporation to form polar TMC solid coating on the PE surfaces and facilitate the quick spreading of lately added aqueous PIP solutions, forming dense and highly cross-linked PA separation layers with superior total heat recovery efficiency and CO2 barrier property. The effects of TMC loading level, PIP concentration, and LSIP reaction time on the structure and performance of PA/PE-TFC THEMs were systematically investigated, leading to the formation of THEMs 0.20P-0.10T-6 with ultra-low CO2 permeance of 0.9 GPU, and high sensible heat exchange efficiency of 94.3 %, water vapor flux of 2128 g m−2·24 h−1, and enthalpy exchange efficiency of 76.8 %.

Contrasting Aqueous Dispersion State of Kaolinite with Different Organic Modification Surfactants

Contrasting Aqueous Dispersion State of Kaolinite with Different Organic Modification Surfactants

A self-assembled surfactant for efficient flotation of cassiterite: Experimental study and DFT calculation

Surfactants of different kinds are important in the flotation of metal oxide ores. In this paper, a combined organic surfactant was formed through self-assembly of salicylhydroxamic acid (SHA) and isopropanolamine dodecylbenzenesulfonate (DBIA). The effects of SHA and DBIA on the flotation behavior of cassiterite were investigated. Density functional theory (DFT) calculations were used to clarify the microscopic adsorption mechanism of SHA and DBIA on the cassiterite surface. The flotation performance of the combined surfactant was investigated to determine the optimum ratio. Subsequently, the self-assembly behavior of the surfactants in aqueous solutions was examined using surface tension tests and molecular dynamics simulations. Flotation experiments and zeta potential, X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), contact angle, and adsorption capacity analyses were used to explore the flotation behavior and adsorption mechanism at the solid–liquid–gas boundary. The maximum flotation recovery of cassiterite were 45.73 % and 71.25 % when SHA and DBIA were used alone. By contrast, with the developed combined surfactant, the flotation recovery at the same reagent concentration was 84.92 %. The SHA/DBIA surfactant co-adsorbed at the aqueous solution interface, which decreased the surface tension of the solution to 4.943 × 10−4 mol/L and resulted in formation of a stable foam layer. These effects altered the surface properties of cassiterite and enhanced its surface hydrophobicity. Overall, this study provides valuable mechanistic insights into the enhanced chelation complexation of self-assembled surface collectors with metal oxides.

Immobilization of collagenase in inorganic hybrid nanoflowers with enhanced stability, proteolytic activity, and their anti-amyloid potential

Organic-inorganic hybrid nanomaterials are considered as promising immobilization matrix for enzymes owing to their markedly enhanced stability and reusability. Herein, collagenase was chosen as a model enzyme to synthesize collagenase hybrid nanoflowers (Col-hNFs). Maximum collagenase activity (155.58 μmol min−1 L−1) and encapsulation yield (90 %) were observed in presence of Zn(II) ions at 0.05 mg/mL collagenase, 120 mM zinc chloride and PBS (pH 7.5). Synthesized Col-Zn-hNFs were extensively characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier transform infrared (FTIR), circular dichroism (CD), fluorescence spectroscopy, dynamic light scattering (DLS) and zeta potential measurements. SEM images showed flower-like morphology with average size of 5.1 μm and zeta potential of −14.3 mV. Col-Zn-hNFs demonstrated superior relative activity across wide pH and temperature ranges, presence of organic solvents and surfactants as compared to its free form. Moreover, Col-Zn-hNFs exhibited excellent shelf life stability and favorable reusability. Col-Zn-hNFs showed the ability to suppress and eradicate fully developed insulin fibrils in vitro (IC50 = 2.8 and 6.2 μg/mL, respectively). This indicates a promising inhibitory potential of Col-Zn-hNFs against insulin amyloid fibrillation. The findings suggest that the utilization of Col-Zn-hNFs as a carrier matrix holds immense potential for immobilizing collagenase with improved catalytic properties and biomedical applications.

Research on the blocking mechanism of oily sewage reinjection based on microfluidic technology

Reinjection into reservoirs to displace oil is an environmentally friendly and efficient way to treat and use produced oily sewage. However, the permeability damage to the reservoir by the small oil droplets in the oily sewage (usually called oil-in-water, OIW) is a huge challenge in oil industry. In this work, microfluidic device is designed to qualitatively and quantitively evaluate the OIW damage using both micro-homogeneous model and micro-heterogeneous model together with core flooding experiments. The results show that OIW can cause serious permeability damage (more than 60%) to the porous media after 50 PV sewage injection due to the adsorption and accumulation of oil drops in four main forms: oil droplet blockage, column oil blockage, cluster oil blockage, and blind oil blockage. To relieve the OIW damage, according to the composition of oil in the produced water, a new oily blockage removal system, which is composed of organic solvent, surfactant, and alcohol, is developed to solve the problem of pore blockage caused by OIW. The three components in blockage removal system cooperate with each other can effectively remove the blockage in pores caused by OIW, and the permeability recovered to more than 96% of the initial permeability values after 20 PV injection of blockage removal system.

Experimental Study on Foam Properties of Mixtures of Organic Silicon and Hydrocarbon Surfactants Regulated by Nano-SiO2 Particles

Experimental Study on Foam Properties of Mixtures of Organic Silicon and Hydrocarbon Surfactants Regulated by Nano-SiO2 Particles