Surfactant Sodium Dodecylbenzenesulfonate Research Articles

Effect of solution pH on removal of anionic surfactant sodium dodecylbenzenesulfonate (SDBS) from model wastewater using nanoscale zero-valent iron (nZVI)

Batch experiments for removal of anionic surfactant sodium dodecylbenzenesulfonate (SDBS) from model wastewater using nanoscale zero-valent iron (nZVI) were conducted to elucidate mechanisms of SDBS removal by nZVI. To clarify the effects of solution pH on removal of SDBS by nZVI, the concentration profiles of Fe ions and dissolved oxygen (DO) were measured besides the concentrations of SDBS and total organic carbon (TOC) at pH of 3, 5, 7 and 9. The SDBS concentration rapidly decreased to less than 4% of the SDBS loadings within 40 min at pH 3, 7 and 9. However, TOC decreases were rather slow and the maximum TOC removal of 62% after 240 min was obtained at pH 7. The XRD patterns confirmed that the main corrosion product was lepidocrocite at pH 5 and 7 while magnetite was dominant at pH 9. The maximum removal of SDBS by nZVI at pH 7 was attributed mainly to the ionic adsorption of anionic SDBS onto the positively charged nZVI surface. The novel kinetic model for dynamic linkage of SDBS removal with concentrations of total eluted iron ions and DO via the formation of iron oxide/hydroxide layer on nZVI surface could simulate the experimental results with the average correlation coefficient of 0.952. The mechanisms of SDBS removal by nZVI at different pH values were clarified and quantified by the proposed kinetic model.

Deaeration of stable coal froth by surfactants to modify the interfacial properties

Overly stable froth is an emerging problem in fuel and mineral processing plants and poses operational and safety concerns. A remedial strategy is not currently available. As a new initiative this study examined three surfactants, dioctyl sulfosuccinate sodium salt (DOSS), sodium dodecylbenzenesulfonate (SDBS) and perfluorooctanoate (PFOA) which vary in both hydrophobic chain and hydrophilic functional group, in deaerating and collapsing overly stable coal froth. The underpinning premise was that an ideal surfactant structure could modify particle surface hydrophobicity and air–liquid interfacial tension in such a way so as to destabilize stable froth. The deaeration tests together with contact angle and interfacial tension measurements indicated that the reduction of contact angle of coal particles played a dominant role in froth deaeration, while the reduction of air–liquid interfacial tension had a negative effect on destabilizing stable froth. The addition of hydrocarbon surfactants DOSS and SDBS could achieve a complete froth deaeration due to their high contents of hydrophilic polar groups and strong adsorption capacity on coal surfaces which could reduce the contact angle of coal particles to near zero. However, PFOA, a fluorocarbon surfactant, could only reduce the contact angle of coal particles moderately and therefore was not effective in deaerating stable coal froth even at a high concentration.

Origin of n type properties in single wall carbon nanotube films with anionic surfactants investigated by experimental and theoretical analyses

We investigated the origin of n-type thermoelectric properties in single-wall carbon nanotube (SWCNT) films with anionic surfactants via experimental analyses and first-principles calculations. Several types of anionic surfactants were employed to fabricate SWCNT films via drop-casting, followed by heat treatment at various temperatures. In particular, SWCNT films with sodium dodecylbenzene sulfonate (SDBS) surfactant heated to 350 °C exhibited a longer retention period, wherein the n-type Seebeck coefficient lasted for a maximum of 35 days. In x-ray photoelectron spectroscopy, SWCNT films with SDBS surfactant exhibited a larger amount of sodium than oxygen on the SWCNT surface. The electronic band structure and density of states of SWCNTs with oxygen atoms, oxygen molecules, water molecules, sulfur atoms, and sodium atoms were analyzed using first-principles calculations. The calculations showed that sodium atoms and oxygen molecules moved the Fermi level closer to the conduction and valence bands, respectively. The water molecules, oxygen, and sulfur atoms did not affect the Fermi level. Therefore, SWCNT films exhibited n-type thermoelectric properties when the interaction between the sodium atoms and the SWCNTs was larger than that between the oxygen molecules and the SWCNTs.

Effect of surfactants on the transport of polyethylene and polypropylene microplastics in porous media

The transport of microplastics in porous media is attracting increasing attention. However, to date, research is limited to polystyrene microplastics. Meanwhile, surfactants can promote solid dispersion to form a stable suspension, possibly allowing microplastics to migrate when attached to a surfactant, which would increase the scope and degree of microplastic pollution, further endangering human health and the stability of the ecological environment. Therefore, in this study, the transport behavior of microplastics in porous media was explored in the presence of surfactants. Herein, polyethylene (PE) and polypropylene (PP) were evaluated while dispersed by two ionic surfactants: cationic surfactant-cetyltrimethylammonium bromide (CTAB) and anionic surfactant-sodium dodecylbenzenesulfonate (SDBS). The influence of different factors (surfactant concentration, ionic strength, pH, flow rate, and multivalent cations) on the transport of microplastics in porous media was explored via quartz sand packed-column experiments. Our experimental results show that the transport abilities of PE and PP increased with increasing surfactant concentration when the surfactant concentration was less than the critical micelle concentration (CMC). In the presence of CTAB and SDBS, physicochemical factors had different effects on the transport of microplastics mainly by controlling Zeta potential, advection diffusion and CMC. The mobility of PE and PP decreased with increasing ionic strength, cation valence and pH, and decreasing flow rate. However, the mobility of PE and PP under CTAB is much greater than that of PE and PP under SDBS, because quartz sand can absorb more CTAB molecules through electrostatic attraction to weaken the collision between microplastics and quartz sand. Further, the transport ability of PP was greater than that of PE under all conditions considered. Notably, the Extended-Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory formed by adding osmotic, elastic, and hydrophobic force could well described the migration behavior of microplastics in CTAB and SDBS well. This research highlights that surfactant has a significant impact on the transport ability of microplastics, and provides a comprehensive understanding of the migration and fate behaviors of microplastics affected by surfactants, which is necessary to prevent and reduce the environmental hazards of microplastics.

Aeromonas immobilized on chitosan for treating high-oil wastewater from kitchens

To effectively solve the serious impact of high oil in the kitchen wastewater on the downstream treatment process, an excellent oil-degrading strain Aeromonas allosaccarophila CY-01 was immobilized to prepare Chitosan-Aeromonas pellets (CH-CY01) by using chitosan as a carrier. Oil degradation condition and efficiency of CH-CY01 pellets were assessed. The growth of immobilized CH-CY01 was almost unaffected, and the maximum degradation rate of soybean oil was 89.7%. Especially at 0.5% NaCl concentration, oil degradation efficiency of CH-CY01 was increased by 20% compared with free cells. In the presence of a surfactant (sodium dodecylbenzene sulfonate) at 1 mg/L, the degradation efficiency of oil by CH-CY01 was increased by 40%. Moreover, using the high-oil catering wastewater as the substrate, more than 80% of the solid oil was degraded with 1% (V/V) CH-CY01 pellets treatment for 7 days, significantly higher than that of free cells. In summary, immobilized CH-CY01 significantly improved the efficiency of oil degradation.

Study on the Influence of Surfactant Addition for Bitumen Separation from Asbuton Rocks using Hot Water Process

Indonesia has a bitumen reservoir in a form of rocks located in Buton Island, Southeast Sulawesi. These rocks contain both bitumen and mineral. Bitumen was mostly used for road preparation, hence bitumen had to be separated from its mineral. It was concluded from previous researches that bitumen extraction using the hot water process had a low bitumen recovery. One way to improve its recovery was by adding surfactant. This research aimed to study the effects of anionic and cationic surfactant addition to the percent recovery of bitumen. There were three main processes of bitumen extraction using hot water namely; preparation, mixing-preheating, and digesting. First, asbuton rocks were ground into fine material, then it was sieved using sieve number 30. Then it was continued by mixing asbuton and diesel oil with a ratio of 60:40 at 250 rpm at 60°C for 30 minutes. Then the second process was done by mixing diesel oil-asbuton and wetting agent solution that contains Sodium Dodecyl Benzene Sulfonate (SDBS) as anionic surfactant and NaOH at 1500 rpm for 30 minutes. The other mixture is Dodecyl Trimethyl Ammonium Bromide (DTAB) as a cationic surfactant and NaOH. In this research, the concentrations of surfactant used were 0.125; 0.25; 0.375; 0.5%, the used NaOH concentrations were constant at 0.5% (% mass), while the variation of temperature used were 60, 70, 80, to 90°C. The product of the digestion process was taken into beaker glass for 24 hours to separate into 3 layers by gravitational force. The top layer is a bitumen-diesel oil solution. The result showed that the performance of SDBS is better than DTAB, this could be because DTAB is positively charged, yet the minerals are negatively charged, so they tend to bind. It can be concluded from this study that the highest percent recovery of bitumen was 72.30 % at a temperature of 90°C with SDBS surfactant concentration of 0.125%, which means anionic surfactant had a better result than cationic surfactant.

Migration behavior of Cr(VI) during the transformation of ferrihydrite-Cr(VI) co-precipitates: The interaction between surfactants and co-precipitates

Redistribution of Cr(VI) in ferrihydrite-Cr(VI) co-precipitates (Fh-Cr) was affected by co-precipitates transformation and coexisting substances. These effects were crucial for predicting the migration path of Cr(VI) in ferrihydrite-Cr(VI) co-precipitates. This work investigated the effects of the extensively used surfactants of anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and cationic surfactant cetyltrimethylammonium bromide (CTAB) on the Fh-Cr transformation and redistribution of Cr(VI) for 10 days at different pH values (5.0, 7.5 and 9.0) and concentration of surfactants (0.5, 2.0 and 5.0 mM). The results showed that SDBS hindered the transformation of Fh-Cr to hematite and tended to transform into goethite. SDBS inhibited hematite formation by inhibiting the aggregation of Fh-Cr particles, and it enhanced the dissolution of Fh-Cr to facilitate the formation of goethite. Affected by the inhibition of Fh-Cr transformation, the process of Cr(VI) redistribution was delayed. CTAB did not affect the transformation of Fh-Cr, but allowed more Cr(VI) to enter the interior of iron minerals. When the surfactants were adsorbed on the Fh-Cr, SDBS decreased the adsorption of Cr(VI) by Fh-Cr, while CTAB increased the Cr(VI) adsorption. The findings of this study contribute to understand the effects of surfactants on the transformation of Fh-Cr and the behaviors of Cr(VI) during this process.

1-dodecanthiol-assisted aqueous synthesis and characterization of Bi[formula omitted]Te[formula omitted] nanotubes

This article reports a novel synthetic methodology for preparing Bi2Te3 nanotubes as well as tailoring their size and aspect ratio, which provides a strong potential interest in the field of thermoelectrics. Bi2Te3 nanotubes were synthesized via a 1-dodecanethiol (DDT) assisted aqueous two-steps synthesis. One of its main advantages is to be easily scalable because it is carried under mild experimental conditions. The complexation of the capping ligand DDT to the bismuth yields to layered structural complexes Bi(DDT)3, which may act as a soft templates promoting the growth of Bi2Te3 nanotubes. The products were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Transmission Electron Microscopy (TEM) and High-Resolution Transmission Electron Microscopy (HRTEM). Microstructure investigations of powders show that the Bi2Te3 nanotubes are 200–500 nm long with an average diameter of 50–100 nm. The HR-TEM and selected area electron diffraction (SAED) results reveal the presence of 20–30 nanometers crystallized nanodomains and support the growth of the nanotubes via a rolling up mechanism of (a, b) planes. Using sodium dodecylbenzene-sulfonate (SDBS), as an additional structuring agent, lowers the yield of Bi2Te3 tubes synthesis and increases the heterogeneity of their size distribution. However, with an increased amount of SDBS very long Bi2Te3 (up to 20μm) tubes have been obtained. As a conclusion, using the capping ligand DDT allows obtaining Bi2Te3 nanotubes in mild conditions according to an easily scalable procedure. Moreover, for the first time the addition of another shape directing agent such as the surfactant SDBS in presence of DDT is shown to be a promising way to tune the dimensions and aspect ratio of these Bi2Te3 nanotubes, and as a consequence tailor their electronic properties, since the longest hollow Bi2Te3 tubes ever synthesized have been obtained.

Using a switchable water to improve sustainable extraction for oil sands by low-concentration surfactant solution

Surfactant extraction is the common method for treating oil sands. However, the recovery of traditional surfactant is difficult, and the oil emulsification phenomenon and generation of tailings are also caused easily. To develop the cleaner and sustainable approach for treating oil sands, a switchable water N, N, N′, N′-tetramethylhexanediamine (TMHDA) was used to improve extraction by surfactant sodium dodecyl benzene sulfonate (SDBS) solution with low concentration. Here, the TMHDA-containing SDBS solution has CO2 switchability because of the electrostatic interaction between SDBS solution and TMHDA with CO2 response, and can be also emulsify reversibly n-heptane, diesel oil, even crude oil, providing the possibility for separating oil from oil sands. The effective extraction of oil sands is performed by 1 mM (less than critical micelle concentration (CMC)) SDBS solution combined with TMHDA, which was also demonstrated by thermogravimetric analyzer, scanning electron microscope and elemental analysis. The residual oil content of oil sands is reduced to 0.515 wt% and 90.8% oil is removed by adding 0.15 g/mL TMHDA. Interestingly, oil is separated and fine sands is separated by introducing CO2, and the TMHDA-containing SDBS is recycled upon N2/65 °C.According to the detection of interfacial tension and Fourier Transform Infrared Spectroscopy (FTIR), it is demonstrated that the improved oil removal is ascribed to the adsorption of SDBS on solid surface and the reduced oil-water interface tension by the addition of TMHDA. Based on the evaluation of economic and environmental value, this sustainable approach exhibits potential application for treating oil sands in practical industry.

Investigation of the Effect of Sonication Time on Dispersion Stability, Dielectric Properties, and Heat Transfer of Graphene Based Green Nanofluids

Natural ester oils are the current target of many industries and electrical utilities as electrically insulating fluids to replace the conventional mineral oils. However, as previously investigated, most natural ester oils are based on edible products, causing a negative impact on the food crisis. Accordingly, nonedible green nanofluids based on cottonseed oil have been targeted in the present study. Additive graphene nanoparticles (0.0015 wt%, 0.003 wt%, 0.006 wt%, and 0.01 wt%) along with surfactant sodium dodecylbenzene sulfonate (SDBS) were used (1:1) due to their promising impact on dielectric and thermal properties. Experimental methods introduced were including characterization of graphene and preparation of dielectric nanofluids (DNFs). The main concern for any nanofluid to be usable in transformer applications is its long-term stability. The effect of various ultrasonication periods (10, 20, 30 and 60-minute) on short-term stability of nanofluids was preliminary investigated by visual inspection, highest short-term stability was obtained at 30-min and 60-min. Considering short-term stability results, the two most stable samples were investigated and compared for long-term stability through ultraviolet-visible (UV-Vis) spectroscopy to find the suitable ultrasonication time. In addition, dielectric and thermal properties of these samples were investigated and compared. Physical mechanisms were discussed for the obtained enhancements considering the effect of ultrasonication period on the number of dispersed nanoparticle sheets per unit volume and the corresponding effect on dielectric and thermal properties.

Effect of nanoparticles concentration on electromagnetic-assisted oil recovery using ZnO nanofluids.

Utilization of metal-oxide nanoparticles (NPs) in enhanced oil recovery (EOR) has generated substantial recent research interest in this area. Among these NPs, zinc oxide nanoparticles (ZnO-NPs) have demonstrated promising results in improving oil recovery due to their prominent thermal properties. These nanoparticles can also be polarized by electromagnetic (EM) field, which offers a unique Nano-EOR approach called EM-assisted Nano-EOR. However, the impact of NPs concentrations on oil recovery mechanism under EM field has not been well established. For this purpose, ZnO nanofluids (ZnO-NFs) of two different particle sizes (55.7 and 117.1 nm) were formed by dispersing NPs between 0.01 wt.% to 0.1 wt.% in a basefluid of sodium dodecylbenzenesulfonate (SDBS) and NaCl to study their effect on oil recovery mechanism under the electromagnetic field. This mechanism involved parameters, including mobility ratio, interfacial tension (IFT) and wettability. The displacement tests were conducted in water-wet sandpacks at 95˚C, by employing crude oil from Tapis. Three tertiary recovery scenarios have been performed, including (i) SDBS surfactant flooding as a reference, (ii) ZnO-NFs flooding, and (iii) EM-assisted ZnO-NFs flooding. Compare with incremental oil recovery from surfactant flooding (2.1% original oil in place/OOIP), nanofluid flooding reaches up to 10.2% of OOIP at optimal 0.1 wt.% ZnO (55.7 nm). Meanwhile, EM-assisted nanofluid flooding at 0.1 wt.% ZnO provides a maximum oil recovery of 10.39% and 13.08% of OOIP under EM frequency of 18.8 and 167 MHz, respectively. By assessing the IFT/contact angle and mobility ratio, the optimal NPs concentration to achieve a favorable ER effect and interfacial disturbance is determined, correlated to smaller hydrodynamic-sized nanoparticles that cause strong electrostatic repulsion between particles.

Preparation and characterization of ionic and non-ionic surfactants impregnated κ-carrageenan hydrogel beads for investigation of the adsorptive mechanism of cationic dye to develop for biomedical applications

In this work, the κ-carrageenan (CRG) hydrogel beads were impregnated by polyethylene glycol tert-octylphenyl ether (Triton X-100, TTX), as a non-ionic surfactant, and sodium dodecylbenzene sulfonate (SDBS), as an ionic surfactant, in the presence of crosslinking agents of potassium chloride and aluminum chloride. The prepared hydrogel beads were examined by FTIR, XRD, SEM, BET, and TGA analysis, which well confirmed their successful impregnation by the surfactants. The results revealed that the spherical/cubic CRG-TTX hydrogels have a higher crystal structure and thermal resistance than spherical CRG-SDBS. It was demonstrated that the impregnation of CRG hydrogel beads with TXX and SDBS surfactants improves their adsorption behavior toward methylene blue (MB) from aqueous media. The surfactant amount significantly effects on adsorbent performance, whereas the best surfactant concentration was found to be half of the critical micellar concentration. The optimum concentration of adsorbents was obtained 1 g L−1, and the best removal efficiencies were achieved in the pH range of 4 to 8. The maximum adsorption capacity was obtained 482.15 mg g−1 and 469.57 at 45 °C for CRG-TTX and CRG-SDBS, respectively. The dye adsorption kinetics followed the pseudo-second-order kinetic model and the obtained adsorption experimental data were in good agreement with the Langmuir isotherm equation. Thermodynamic study indicated that the process was spontaneous in nature and endothermic. The polymeric microspheres can be employed to deliver drugs in a rate-controlled and sometimes targeted manner.

Optimization of synthesis of geopolymer adsorbent for the effective removal of anionic surfactant from aqueous solution

This paper describes the optimization of synthesis of fly ash based geopolymer (FAGP) for removing the anionic surfactant sodium dodecylbenzene sulfonate (SDBS) using response surface methodology (RSM) by varying the synthesis parameters of silica to alumina (Si/Al), sodium to alumina (Na/Al) and water to solid (W/S) ratios with the adsorption capacity as the response. The geopolymer samples were designed, synthesized, characterized, used for removing SDBS surfactant, and regenerated. Surface area and pore size analysis, Fourier Transform Infrared Spectroscopy (FTIR) analysis, phase analysis, and microstructural analysis confirmed the synthesis of mesoporous and amorphous geopolymers with the presence of pores, cavities and rods in the geopolymer structure. Geopolymer sample synthesized with the composition of Si/Al-2.87, Na/Al-1.0 and W/S-0.35 (FAGP-2) achieved maximum surface area of 59.512 m2/g and displayed the highest adsorption capacity of 743.706 mg/g and removal efficiency of 84.5%. The ANOVA analysis showed a correlation coefficient (R2) of 0.952, F-value of 22.27, and p value of 0.05 which indicated the significance of the model and lack of fit was non-significant which showed good fitting of the experimental data to the quadratic model with 95% confidence level. The proposed geopolymer composition of Si/Al-2.353, Na/Al-1.056, and W/S-0.339 achieved adsorption capacity of 730.212 mg/g which is 99% similar to the predicted adsorption capacity. Thermal method successfully regenerated SDBS adsorbed geopolymer with only 13.8% loss of adsorption capacity after five cycles of regeneration. The adsorption capacity of optimized geopolymer is higher than other adsorbents such as cross-linked chitosan films, commercial activated carbon, surface functionalized mesoporous silica nanoparticles, multi-walled carbon nanotubes (MWCNTs), and others used for removing SDBS surfactant and only amino crosslinked chitosan microspheres (ACCMs) has higher adsorption capacity than geopolymer. This shows that geopolymer can also be effectively used to adsorb SDBS surfactant from wastewater.

4S consideration (synthesis, sonication, surfactant, stability) for the thermal conductivity of CeO2 with MWCNT and water based hybrid nanofluid: An experimental assessment

The main objective of the present study is to investigate the impact of nanofluid stabilization techniques (hybrid stabilization approach, i.e., a combination of different mechanical and chemical methods) on the stability and thermal conductivity of CeO2+MWCNT (80:20)/water based hybrid nanofluid. The nanofluid has been prepared by using the two-step method, and a broad range of ultrasonication time (30, 60, 90, 120, 150, and 180 min) has been used. Furthermore, different kinds of charged surfactants, two anionic (sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulphate (SDS)), two cationic (cetyltrimethylammonium bromide (CTAB), distearyl dimethylammonium chloride (DDC)), and two polymers (gum Arabic (GA), PVP (polyvinyl pyrrolidone)) have been added to the base fluid with a different nanoparticle to surfactant mixing ratios (5:0, 4:1, 3:2, 2:3 and 1:4). The prepared samples were investigated at different pH values and different preparation days (15th, 30th, 45th,60th, and 90th day) to evaluate which surfactant and mixing ratios are sufficient to achieve a stable nanofluid for more than 90 days. The observed optimum volumetric mixing ratio of surfactant and CeO2+MWCNT nanoparticle, pH level and sonication time are around 3:2, 9.5, and 90 min, respectively, for which hybrid nanofluid yields maximum zeta potential value as an indicator of nanofluids long term stability. The results of zeta potential analysis indicated that CTAB surfactant shows the best impact up to the 30th day from preparation, after the 30th day, the SDBS surfactant shows the highest degree of stability of the hybrid nanofluid applying 3:2 mixing ratio and 90 min sonication. Results clearly showed that the nanofluid hybrid stabilization approach has a strong relation with thermal conductivity. The addition of higher amounts of surfactant (more than 3:2 mixing ratio) caused a small thermal conductivity reduction. Additionally, precise assessments of the surfactant effect on a hybrid nanofluid's surface tension have also been studied. Finally, a correlation to predict the experimental value of thermal conductivity has been proposed from the experimental data, which could be beneficial for various heat transfer applications.

Application of polyaniline nanocomposites in the trapping of thorium ions from aqueous solutions:Adsorption equilibrium, kinetics and thermodynamics

In this study, the adsorption behavior of Th(IV) ions was investigated using polyaniline (PAni) nanocomposites. Nanocomposites were synthesized with two types of dopants (H3PO4 and H2SO4) and two oxidants ((NH4)2S2O8 and KIO3) in the presence of two different surfactants (sodium dodecylbenzene sulfonate (SDBS) and hydroxypropyl cellulose (HPC)). The structure of the synthesized polymers was examined using FT-IR and SEM analyses. Adsorption of Th(IV) ions onto the synthesized polymers with a supreme removal (99.98%) was obtained by the H3PO4-doped polymers, especially for the sample with KIO3 oxidant and SDBS surfactant (PAni-2-1-S). BET, TGA and DSC analyses were also employed for the adsorbent characterization. The effect of main parameters was also investigated for the removal of Th(IV) ions from aqueous solutions by PAni-2-1-S. The pseudo-second-order kinetic and Langmuir isotherm models were in full agreement with the kinetic and isotherm experimental data, respectively and the highest adsorption capacity of the PAni-2-1-S was observed to be 68.49 mg/g. Thermodynamic data demonstrated the spontaneous and endothermic behavior of this adsorption process.

Adsorption Kinetics, Isotherms, and Thermodynamics of Removal of Anionic Surfactant from Aqueous Solution Using Fly Ash

Surfactants are organic compounds which can be used in several applications. However, they can contaminate world water resources causing detrimental effects to human beings, aquatic life, and animals. This paper investigates the adsorption kinetics, isotherms, and thermodynamic properties for the removal of an anionic surfactant, sodium dodecylbenzene sulfonate (SDBS), using fly ash. Characteristics of fly ash such as surface area and pore size analysis and the point of zero charge (PZC) were determined. The effects of parameters such as pH, surfactant concentration, and temperature and the adsorption kinetics, isotherms, and thermodynamic properties and adsorption mechanism were determined. Fly ash is a mesoporous material having surface area and pore size of 1.079 m2/g and 9.813 nm and PZC at pH 6.58. pH 2 and the temperature 25 °C were optimum for adsorbing SDBS onto fly ash. The adsorption capacity and removal efficiency increased by increasing the concentration of SDBS from 100 to 2000 mg/L, indicating that the increase of surfactant concentration could not saturate the surface of fly ash. The pseudo-second-order and the Langmuir isotherm models showed best fit to the adsorption data and the thermodynamic properties described adsorption as an exothermic, barrierless, non-spontaneous, and entropy-reducing reaction which is more feasible at a lower temperature of 25 °C. This indicated that the adsorption occurs by both physisorption and chemisorption with monolayer coverage of SDBS on the surface of fly ash. SDBS surfactant adsorbed onto fly ash mainly through electrostatic interactions between oppositely charged SDBS and fly ash.

Surfactant Sodium Dodecyl Benzene Sulfonate Improves the Efficiency and Stability of Air‐Processed Perovskite Solar Cells with Negligible Hysteresis

The device performance of organic–inorganic hybrid halide perovskite solar cells (PSCs) is highly dependent on the quality of perovskite layer. Herein, a multifunctional chemical additive strategy is reported to simultaneously improve the efficiency and stability of fully air‐processed PSCs. The planner methylammonium lead trihalide (MAPbI3)‐based PSCs incorporating sodium dodecyl benzene sulfonate (SDBS) exhibit a champion power conversion efficiency (PCE) of 19.20% and negligible hysteresis, which is one of the top efficiencies of MAPbI3‐based PSCs made in air. The increased efficiency is due to the reduction of defects and inhibition of ion migration in the perovskite films. Furthermore, the enhancement of device performance and stability can also be ascribed to highly preferred and efficient perovskite crystals protecting the perovskite films from humidity. The corresponding unencapsulated device retains 92.34% of its initial efficiency after 90 days (>2100 h) storage in air and maintains 85.20% of its original PCE after being exposed to 85 °C for 27 h. The results indicate that SDBS is a promising chemical additive to enhance the performance of air‐processed PSCs for future applications.

Dynamics of interfacial layers for sodium dodecylbenzene sulfonate solutions at different salinities

This study investigates the adsorption mechanisms and the dilational surface rheology of the anionic surfactant sodium dodecylbenzene sulfonate (SDBS) at the air–liquid interface, in the presence and absence of NaCl over a wide range of SDBS concentrations. We also evaluate the Langmuir and Frumkin models in order to predict the dynamic adsorption of SDBS solutions. Our results reveal that the equilibrium surface tension of SDBS solutions is a monotonically decreasing function of NaCl concentration. However, the dilational viscoelastic properties of SDBS solutions are found to be a non-monotonic function of NaCl concentration. NaCl manifests opposing effects on the dilational viscoelastic moduli of the gas–liquid interface, depending on the frequency of surface oscillation and surfactant bulk concentration. Our measured dilational surface elasticity and viscosity data show a shift in the surfactant transition concentration, at which the viscoelastic moduli reach their maximum values, towards smaller surfactant bulk concentrations with increasing salt concentration. It is attributed to suppressing the electrostatic repulsion between the hydrophilic head groups of surfactant molecules in the presence of electrolytes. The maximum viscoelastic moduli at different NaCl concentrations is found to be the reflection of the relative impact of enhanced adsorption and increased diffusion exchange between bulk and interface.

Study on the types and formation mechanisms of residual oil after two surfactant imbibition

For investigating the types and formation mechanisms of residual oil after surfactant imbibition, the easy-emulsifying surfactant Sodium Dodecylbenzene Sulfonate (SDBS) and ultra-low interfacial tension surfactant Sodium Oleate (SOL) were selected. The visual micromodel was adopted to observe the oil morphologies, while the rheometer and the emulsion stability analyzer were applied to analyze formation mechanisms. According to micro experiments, the main types of residual oil after SDBS imbibition are columnar, cluster, blind-end and small drop residual oil whose structure was small fragmented droplet. As for SOL solution, they are mainly blind-end and island residual oil. The formation mechanism of columnar and cluster residual oil is capillary force offsetting, the direction of capillary force forms the blind-end residual oil, while the Marangoni effect and snap-off effect are responsible for island residual oil. The small drop residual oil is from emulsification, which always appears at the intersection of multiple flows. The aromatic groups of SDBS can promote the emulsion more stable by increasing the strength of interfacial film, hence the small drop residual oil only exists after SDBS imbibition.

Enhanced extracellular electron transfer of yeast-based microbial fuel cells via one pot substrate-bound growth iron-manganese oxide nanoflowers

The growth of manganese oxide decorated iron oxide nanoflowers atop polyethylenimine functionalized carbon felt via surface-bound iron particle seeds is explored with and without the aid of a surfactant ligand in a one-pot aqueous solution for the first time. Widespread, uniquely shaped, rough nanocrystal growth is shown to develop on the hydrophilic surface of functionalized carbon felt fibers and the growth is achieved using a seed, initiator, reducer, and ligand mixture. The structure of the iron-manganese oxide nanoflowers are optically examined, and the anodic viability of the modified carbon felt in microbial fuel cells is determined through analysis of the stimulation and maturation of yeast via electrochemical characterization. The developmental growth of the iron-manganese oxide nanoparticles with the beneficial addition of the surfactant ligand, sodium dodecylbenzenesulfonate, and different ratios of iron to manganese are observed to have an effect on the condition of yeast biofilm inhabitancy, viability, and the resulting electrochemical behaviour. The best power density of 5.8 ± 0.61 W m−2 is achieved when utilizing this surfactant mediated iron-manganese oxide nanoparticle growth technique to the microbial fuel cell anode.