Sodium Dodecyl Benzene Sulfonate Concentration Research Articles

Synthesis and optimization of bentonite enforced poly (acrylamide/co- sodium dodecylbenzensulfonate) preformed particle gels for conformance control in high salinity reservoirs

Water production in the matured oil reservoir is a big concern to the petroleum industry because of increased oil production costs and water discharge problems. In the present study, Poly (Acrylamide/Co- Sodium dodecylbenzene sulfonate (SDBS)) preformed particle gels (PPG) was synthesized, characterized, and evaluated as a conformance control agent for the high-temperature and high-salinity conditions. The rheological properties, along with the chemical and thermal stability of the synthesized PPGs were enhanced through optimization by integrating new functional groups (SDBS) into their structure to resist as high as 10% salinity and 100 °C. A succession of 16 experiments with varying amounts of acrylamide, SDBS and bentonite concentrations were conducted to obtain the optimum composition to yield the best PPG. The results showed improved swelling ratio, gel strength, rheological properties and thermal stability of the PPGs synthesized. A Delay in degradation of bentonite impregnated PPGs was observed from 37 days to 120 days @100 °C, whereas the increase in water residual resistance factor was 184.6%. The use of low-cost bentonite clay as a new material, in place of costly nanoparticles in nano-PPG, would like to reduce to cost of effective water shutoff to reduce water production.

Impact of Sodium Dodecyl Benzene Sulfonate Concentration on the Stability of the Crude Oil–Mineral Water Interfacial Film: A Molecular Dynamics Simulation Study

The interfacial behavior of surfactants exerts a considerable impact on the chemical flooding-produced liquid treatment project. For circumventing the limitations of model simplification and single-factor simulation of previous molecular dynamics (MD) studies, this paper based on the experimental results of crude oil-phase and water-phase composition constructed different simulation systems of “crude oil/SDBS/mineral water” considering the concentration of sodium dodecyl benzene sulfonate (SDBS). The impact of SDBS concentration on the stability of the crude oil–mineral water interfacial film was explored, and the simulation results were verified by comparing with the simulation system of “crude oil/SDBS/pure water” and interfacial tension experiments. The simulated results showed that the SDBS molecules in the system exist in the form of a monolayer film after dynamic relaxation equilibrium, and with the increase in concentration, the number of SDBS molecules per unit area of the film increases, and the molecular chain bending characteristics are weakened. The order of the effect of inorganic cations on the aggregation degree of SDBS is Ca2+ > Na+ > K+ > Mg2+. When the concentration of SDBS increased from 0.15 to 0.70 mol/L, the total oil water interfacial film thickness increased from 1.433 nm in the crude oil/SDBS/mineral water system and 1.272 nm in the crude oil/SDBS/pure water system to 2.125 nm in the crude oil/SDBS/mineral water system and 2.398 nm in the crude oil/SDBS/pure water system. The absolute value of interface formation energy increased from 1223.59 and 1236.32 to 2739.19 and 3033.64, respectively, which are also basically consistent with the experimental results of interface tension. Furthermore, inorganic ions will weaken the performance of the surfactant SDBS and detrimentally affect the structural strength and stability of interfacial films. These results offer useful insights into the stabilization mechanism of oil–water emulsions. In particular, they provide a basis for the design and optimization of new pathways for oil–water emulsion instability in oilfield development.

Evaluation of the impact of guar gum applied to chemical enhanced oil recovery on produced water treatment using a SDBS-Chitosan flocculant system

ABSTRACT Chemical enhanced oil recovery (cEOR) is a process that involves the injection of chemicals (like polymers) to improve oil recovery. These processes generate a lot of produced water (PW) that needs to be treated properly for final disposal in the environment. This work has the goal to evaluate the influence of the injection biopolymer guar gum on PW treatment, as well the oil removal efficiency (ORE) of a flocculant system composed by the bioflocculant chitosan and sodium dodecyl benzene sulfonate (SDBS). The flocculation-flotation experiments were planned and carried out based on a design of experiments (central composite rotatable design – CCRD). It was possible to find out that guar gum concentration did not impact oil removal efficiency in a statistically significant way. But chitosan and SDBS concentrations were statistically significant, achieving better ORE when chitosan concentration is between 50 and 100 ppm and SDBS concentration is higher than 200 ppm, achieving a maximum of 86% of ORE at concentrations of 75 ppm and 250 ppm, respectively. The findings of this study can help for better understanding of how nonionic injection biopolymers impact on PW treatment and to propose the use of chitosan as a flocculant along with SDBS to enhance PW treatment.

Transport of perfluorooctanoic acid in unsaturated porous media mediated by SDBS

Per– and polyfluoroalkyl substances (PFAS) contamination is ubiquitous and likely co–exist with hydrocarbon surfactants in the subsurface environment. The transport of PFAS in unsaturated porous media (quartz sand–packed columns) with an anionic hydrocarbon surfactant was investigated using perfluorooctanoic acid (PFOA) and sodium dodecyl benzene sulfonate (SDBS) as representative PFAS and hydrocarbon surfactant at 1.5 and 30 mM NaCl, respectively. Our results show that SDBS inhibited the retardation of PFOA during transport. The degree of the inhibited retardation was more significant at higher concentration of SDBS (CSDBS) for a given concentration of PFOA (CPFOA) and higher ionic strength. In contrast, PFOA only marginally affected the transport of SDBS under all tested conditions. This is mainly due to the greater surface activity of SDBS with respect to PFOA, favoring the competitive preferential adsorption of SDBS at the air–water interface and then the transport of PFOA in the unsaturated sand. This assumption is further supported by the greater air–water adsorption coefficient (Kai) and surface excess (Γ) for SDBS than those for PFOA, as well as the surface tension isotherms that fairly weighted toward to SDBS in the binary PFOA–SDBS system. Our findings indicate the critical role of anionic hydrocarbon surfactant in retarding PFOA transport in unsaturated zone. This should be considered when assessing the transport potential and environmental risk, and developing remedial strategies of PFAS in the subsurface environment.

Sodium Dodecylbenzene Sulfonate Assisted Electrodeposition of MnO2@C Electrode for High Performance Supercapacitor

In this work, MnO2&SDBS electrodes with nano-honeycomb morphology were prepared by ultrasound-assisted electrochemical deposition using sodium dodecylbenzene sulfonate (SDBS) as a surfactant agent. The effect and mechanism of SDBS on the morphology of MnO2 nanomaterials during the preparation of MnO2 by electrochemical anodic oxidation was systematically investigated by varying the content of SDBS in the precursor solution. When the SDBS concentration is 2 g · l−1, the resulting electrode has the best electrochemical performance, and the specific capacitance is up to 407 F · g−1 at the current density of 1000 mA · g−1. To further enhance its performance, a carbon coating layer was deposited on the surface of the electrode using a method similar to chemical vapor deposition. Finally, the MnO2&SDBS@C electrode with a three-dimensional net-to-film composite structure with a high specific surface area, hierarchical structure and interconnect with nickel foam supports were obtained. The electrode has excellent electrochemical performance, and the specific capacitance is still up to 289 F · g−1 at a high current density of 5000 mA · g−1. Furthermore, the specific capacitance of the electrode was maintained at 83.9% after 500 cycles of charging and discharging at a current density of 2000 Am·g−1.

Screening the synergy of sodium dodecylbenzenesulfonate and carboxymethyl cellulose for surfactant-polymer flooding

Carboxymethyl cellulose (CMC) has emerged in oil and gas industries as a superior substitution to the conventional HPAM and xanthan gum (XG) for high viscosity polymer flooding application. In this study, the combined effect of conventional surfactant, sodium dodecylbenzenesulfonate (SDBS) and CMC for potential surfactant-polymer (SP) flooding in enhanced oil recovery (EOR) has been investigated. Thereafter, SDBS – CMC interaction and the functional groups present in CMC were appropriately identified. The presence of various C–O bonds signifies the existence of carboxymethyl group which greatly influence the rheological properties of CMC solution. The behaviour of SDBS–CMC was characterized by their viscosity, shear rate, solubilization, wettability, and surface tension. Tertiary flooding utilizing SDBS-CMC was performed and compared to commercial SDBS-XG SP flooding. The results indicate several SDBS-CMC combinations are favourable for EOR application. Solution viscosity shows direct relationship with CMC concentrations. Consequently, at any given SDBS concentrations, significant increment was observed at 0.3 wt% and above. However, the trend displayed inconclusive relation to SDBS fractions. Majority of the SDBS-CMC combinations generate Winsor III emulsions particularly at CMC of 0.2 and 0.3 wt%, while Type II were observed in few combinations. Increasing CMC concentrations increased the contact angle, while gradual reductions were observed with SDBS concentrations. The gradual reduction in surface tension was highly influenced by the addition of CMC rather than SDBS. A novel combination of 0.3 wt% SDBS and 0.4 wt% CMC possessed an encouraging criterion in term of viscosity, solubilization, and surface tension reduction for EOR application. Flooding experiment from several SDBS-CMC combinations proved to recover additional oil ranging 16.4–20.2% of oil initially in place (OIIP). The trend in incremental oil recovery is similar to that of when utilising SDBS-XG.

Utilization of amphiphilic antihistamines drugs to enhance micellization of anionic surfactant and improve the binding and solubility of Itraconazole drug

Many salt-based medicines are used in pharmaceutical formulations as active components. Excipients performance can be improved by using these medicines. The use of amphiphilic antihistamine medications (diphenhydramine hydrochloride (DPC) and cetirizine hydrochloride (CTZ)) to improve sodium dodecylbenzene sulfonate (SDBS) micellization is demonstrated in this work. DPC/CTZ considerably lowered the critical micelle concentration (CMC) of SDBS in aqueous media by measuring conductivity. SDBS micelles demonstrated a greater electrostatic interaction with CTZ than DPC micelles, based on counterion binding (βc and B) and binding constant (Kb) values. The DPC/CTZ mean ion occupancy (i0) per SDBS micelle was also calculated using the UV spectroscopy experiment. For SDBS micelles, we observed that DPC and CTZ had i0 values of 1.700 and 2.622, respectively. The electrostatic interaction between the medication and the surfactants was shown to be controlling the i0 levels. The medicine Itraconazole (ITZ), which is poorly water-soluble, was found to be more soluble in SDBS micelles containing CTZ than in DPC combinations. At 0.002 mol L-1 in the aqueous medium, the greatest i0 values of ITZ were 185 in SDBS + DPC and 203 in SDBS + CTZ. The CMC and the binding behaviour of drug-micelles were found to be critical determinants in controlling ITZ drug solubilization. Finally, we concluded that the above formulation might be used in the pharmaceutical industry to improve multi-drug delivery systems.

Effect of Sodium Dodecylbenzene Sulfonate on the Wetting Mechanism of Tunliu Coal

AbstractCoal dust in the coal mining process may lead to a serious threat to the safety and health of miners. The addition of surfactants during coal seam water infusion can significantly improve the effect of dust suppression, so it is crucial to study the influence mechanism of surfactants on coal wettability. The variation of the hydration film thickness on the Tunliu coal surface at different concentrations of sodium dodecylbenzene sulfonate (SDBS) solution was investigated by atomic force microscopy. The experimental results indicate that the hydration film thickness increases initially and decreases afterward with the SDBS solution concentration increase, with a maximum value of 11.4 nm. The surface free energy (SFE) of coal molecules adsorbed with different numbers of SDBS molecules were calculated using two coal molecule cell models developed by Materials studio 8.0, and the simulation results display a good agreement with the experiments. The higher the SFE, the greater the hydration film thickness on the coal surface, and the stronger the enhancement effect of SDBS solution on the wettability of coal at the corresponding concentration. The interface formation energy (IFE) and cohesive energy density (CED) of coal molecules after adsorption of SDBS molecules were calculated separately. It was found that when three SDBS molecules were adsorbed, the absolute value of IFE and CED reached the maximum, and each SDBS molecule had the strongest average effect on coal molecules, the bond between them would be tighter. SFE simulations are helpful to optimize the selection of surfactants for practical engineering applications.

Improving basalt wettability to de-risk CO2 geo-storage in basaltic formations

CO2 geo-storage in basaltic formations has recently been identified as a viable option to rapidly dispose large quantities of CO2 , hence mitigating anthropogenic CO2 emissions. However, it has been shown that basalt is weakly water-wet or intermediate-wet at typical storage conditions, which reduces capillary trapping capacities and increases lateral and vertical spreading of the CO2 plume; and these effects increase project risk. We thus propose here to prime basalt surfaces with anionic surfactant (here we used sodium dodecyl benzene sulfonate), and demonstrate that such priming is highly efficient, and renders the basalt completely water-wet even at high pressures and minute sodium dodecyl benzene sulfonate concentrations. Such a wettability alteration can therefore significantly de-risk storage projects. This work aids in the improvement of CO2 storage in basaltic formations and supports implementation of industrial-scale CO2 geo-sequestration and climate change mitigation. Cited as: Iglauer, S., Al-Yaseri, A. Improving basalt wettability to de-risk CO2 geo-storage in basaltic formations. Advances in Geo-Energy Research, 2021, 5(3): 347-350, doi: 10.46690/ager.2021.03.09

ANALISIS NATRIUM DODESILBENZENA SULFONAT DALAM IKAN LELE SECARA MASERASI DAN SPEKTROFOTOMETRI UV-VIS MENGGUNAKAN METILEN BIRU

Method validation of sodium dodecylbenzene sulfonate (SDBS) analysis in catfish by maceration and UV-Vis spectrophotometry using methylene blue active substances (MBAS) method was performed. The first stage of this research was method validation comprising correlation coefficient, sensitivity, Limit of Detection (LOD), Limit of Quantitation (LOQ), precision, and accuracy. The extraction of SDBS by maceration with methanol for 16 h and analysis by UV-Vis spectrophotometry using MBAS were performed. Then, this method was applied to analyze SDBS in catfish. The results of validation of SDBS analysis in cultivated catfish give correlation coefficient 0.9944, sensitivity 10.57 × 104 L mol-1 cm-1, LOD 0.01776 mg/L, LOQ 0.05922 mg/L, precision 0.1351-1.300 %, and accuracy 87.64-90.01 %, respectively. The SDBS concentrations in fish increase with the increase in the SDBS concentration in cultivating water. Bioconcentration Factor (BCF) values were inversely proportional to the concentration of SDBS in the cultivating water. The concentrations of SDBS on catfish, tilapia, and carp in traditional markets were 5.719-8.162; 5.180-6.548; and 2.973-5.874 mg/kg, respectively. In general, analysis method of SDBS in catfish by maceration and UV-Vis spectrophotometry with MBAS show a good result and can be used as a routine analysis in fish.

Dimethyl Sulfoxide-Free and Water-Soluble Fluorescent Probe for Detection of Bovine Serum Albumin Prepared by Ionic Co-assembly of Amphiphiles.

Detection of bovine serum albumin (BSA) is an important issue in the sense of medical applications and enzymatic reactions; however, the recently developed fluorescent probes require the involvement of dimethyl sulfoxide (DMSO), which may be detrimental to proteins. In this study, we demonstrated a DMSO-free and water-soluble fluorescent probe prepared by ionic co-assembly of amphiphiles. The cationic amphiphile is a newly designed molecule (denoted by DPP-12) bearing a conjugated diketopyrrolopyrrole (DPP) and two tetraphenylethylene groups. It turns out that the fluorescence emission of DPP-12 depends on the amount of anionic amphiphilic sodium dodecyl benzene sulfonate (SDBS). The fluorescence intensity first increases and then decreases with the concentration of SDBS, and each branch presents a linear relationship. BSA consumes SDBS by the formation of complexes, thus leading to an increase of fluorescence intensity of the mixed solution of DPP-12 and SDBS. Therefore, the mixed solution of DPP-12 and SDBS was applied as a fluorescent probe to detect the low concentration of BSA by back-titration. This fluorescent probe does not require DMSO and has good tolerance to metal ions in blood and good photostability. The limit of detection is as low as 940 nM, almost 3 orders of magnitude lower than the content in organisms.

Production of phenolic compounds in catalytic pyrolysis of bagasse lignin in the presence of Ca0.5Pr0.5FeO3

Herein, sodium dodecylbenzene sulfonate (SDBS) was used as a template to control the synthesis of Ca0.5Pr0.5FeO3. Its microstructure, composition, and morphology were detected via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The properties of catalyzing bagasse lignin (BL) pyrolysis were determined by thermogravimetric analysis (TG) test and evaluation of a fixed bed alumina microreactor. The results show that the sample Ca0.5Pr0.5FeO3 regulated by SDBS has a cubic crystal phase, and the addition of SDBS does not cause phase transition. Moreover, when the SDBS concentration is 0.10 mol/L, the particle size is 200–500 nm and the specific surface area is 11.26 m2/g. The yields of gas, liquid, and solid products in the BL catalytic pyrolysis are 39.58 wt%, 26.76 wt% and 32.36 wt%, respectively. The contents of CO2 and CO decrease from 54.07% and 4.98% to 45.29% and 3.23%, respectively. The liquid products are mainly guaiacol, syringol, and phenol, and the total selectivity of phenols is 83.67%, accompanied by a small amount of non-aromatic oxygen-containing compounds (five-membered ring (furan) or ester). Compared with the BL pyrolysis and Ca0.5Pr0.5FeO3 catalytic pyrolysis products, the selectivity of guaiacol compounds increases by 43.26%, while those of syringol compounds and phenylketones decrease by 30.08% and 3.39%, respectively. The selectivity of 2,6-dimethoxyphenol is 28.37%. After five catalytic pyrolysis-regeneration cycles, the characteristic peaks of the catalyst do not change significantly and the particles are uniform, suggesting that the catalyst has good crystal phase stability and regeneration stability.

Foam fractionation for the separation of SDBS from its aqueous solution: Process optimization and property test

Foam fractionation is an adsorption bubble separation technique allowing recovery and immediate reuse of surfactants. This work was aimed at investigating the variations in recovery efficiency and physicochemical property of sodium dodecyl benzene sulfonate (SDBS) through multiple foam fractionation operation. First, a suitable SDBS concentration of 0.05 g/L was determined for preparing feeding solution. Subsequently, effects of volumetric air flow rate, height ratio of liquid phase and foam phase, and pore diameter of gas distributor on recovery efficiency of SDBS were investigated, respectively. Response surface methodology (RSM) was used to optimize the operating conditions of foam fractionation for separating SDBS. Under the conditions of volumetric air flow rate 80 mL/min, height ratio of liquid phase and foam phase 1:2, and pore diameter of gas distributor 0.180 mm, enrichment ratio and recovery percentage of SDBS were 134.83 ± 6.74 and 63.43 ± 3.17%, respectively. In repetitive separation experiments, the maximum separation number of recovered SDBS by foam fractionation was 3. Experimental results of surface activity and foam properties of recovered SDBS solution suggested that the interfacial adsorption and desorption processes had induced the structural transition and irreversible aggregation of SDBS molecules after multiple foam fractionation operation.

Preparation, Stability and Thermal Characteristic of Al₂O₃/Bio-Oil Based Nanofluids for Heat Transfer Applications.

Conventional thermal fluids with suspended nanoparticles, known as nanofluids, have been developed for heat transfer applications. Heat transfer loss could be reduced significantly if the thermophysical properties of the heat transfer fluid are improved, which to some extent, could reduce the present global environmental challenges associated with energy utilization, such as climate change and global warming. In this work, the role of the concentration of sodium dodecyl-benzene sulfonate (SDBS) in the stability of Al₂O₃/bio-oil nanofluid is investigated the zeta potential value, and its implications to the viscosity and thermal conductivity of the nanofluid are explored. The bio-oil based nanofluid is fixed using a two-step method in which the prepared base fluid is added with 13-nm alumina nanoparticles powder. Various weight fractions of SDBS (0.1, 0.2, 0.4, 0.6, and 1.0 wt%) are used for both 0.1 and 0.2 wt% Al₂O₃ to investigate the significance of the stability of a nanofluid on its thermal conductivity and viscosity. Results indicate that a stable nanofluid has reduced viscosity and increased thermal conductivity.

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.

Investigation into the Influence of Sodium Lignosulfonate, Anionic Surfactants, and Their Mixtures on the Copper Cementation Rate by Zinc

This article is devoted to the influence of sodium lignosulfonate (SL), anionic surfactants (sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate (SDBS)), and their mixtures on the copper cementation rate by zinc. The results demonstrated a copper cementation rate decreasing at LS and SDBS concentrations increasing. Excessive zinc consumption was also detected on copper-ion cementation due to LS and SDBS anion adsorption onto positively charged zinc cathodic areas and copper particles. This led to a decrease in the growth rate of nuclei of copper particles and energy consumption for the formation of new nucleation centers, as well as the creation of conditions for reducing the overvoltage of hydrogen evolution. At the same time, an increase in temperature led to zinc consumption decreasing in the presence of LS. The reagents under investigation could be ranked according to their degree of negative influence on copper cementation increasing in the following order: SDS < SDBS < LS. Testing LS and SDS mixtures showed their irregular influence on the copper cementation rate at different temperatures. In experiments with LS and SDBS mixtures, a linear decrease in the copper-ion cementation rate upon an increase in SDBS concentration and simultaneous zinc-consumption enhancement was fixed. Due to the negative influence of the investigated reagents, we offered a purification method from organic impurities through the use of multilayered alumosilicates modified by cationic surfactants. The results indicate the high effectiveness of removing organic impurities from solutions, which allowed us to increase the cementation rate in the presence of the LS and SDBS mixture by 50% while, at the same time, decreasing zinc consumption.

Study into the effect of sodium lignosulfonate, anionic surfactants and their mixtures on the rate of copper ion cementation by zinc

The article focuses on the effect of sodium lignosulfonate (LS), anionic surfactants (sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate (SDBS)), and their mixtures on the rate of copper cementation by zinc. The results obtained demonstrate a decrease in copper cementation rate with the increasing LS and SDBS concentrations. There was also excessive zinc consumption for copper ion cementation noted due to LS and SDBS anion adsorption on positively charged zinc cathodic areas of the cementing agent and the precipitate. This led to a decrease in the rate of copper particle nucleation, energy consumption for forming new copper nucleation centers, and conditions for hydrogen overpotential reduction. In addition, rising temperature led to a decrease in zinc consumption in the presence of LS. Surfactants under investigation may be ranked by the negative impact on copper ion cementation in an ascending order as follows: SDS &lt; SDBS &lt; LS. LS + SDS mixture testing showed its irregular effect on copper cementation rate at test temperatures. Experiments with LS and SDBS mixtures demonstrated a linear decrease in copper ion cementation rate with increasing SDBS concentration and simultaneously rising zinc consumption. Due to the negative impact of investigated reagents discovered, we proposed a method for removing organic impurities from solutions using multilayered aluminosilicates modified by cationic surfactants. The results obtained indicate the high effectiveness of organic impurity removal from solutions providing for a 50 % increase in cementation rate in the presence of LS + SDBS mixture together with a decrease in zinc consumption.

Effects of exposure to anionic surfactants (SDBS and SDS) on nitrogen removal of aerobic denitrifier.

In order to explain the effect of anionic surfactants on aerobic denitrification in the urban river, sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfonate (SDS) were added in aerobic denitrifier and the efficiency of nitrogen removal, microbial mechanisms, and enzyme activity was investigated in this study. The results showed that the total nitrogen (TN) and the nitrate nitrogen ( ) removal efficiency decreased as an increase of SDBS concentration. In contrast, 59.70% of the TN and 75.12% of were removed as the SDBS was 0mg/L (Control). When SDBS was 200mg/L (SDBS-200), the removal efficiency of TN and was reduced to 4.92% and 4.00%, respectively. However, the denitrification efficiency was significantly accelerated when the concentration of SDS increased, except for 200mg/L treatment (SDS-200). As the SDS increased from 0 to 100mg/L (SDS-100), the removal efficiency of TN and raised from 59.70% to 70.8% and from 75.12% to 85.08%, respectively. The community structure of aerobic denitrifiers was significantly affected in the SDBS and SDS. While the Cupriavidus and Achromobacter were dominant genera in the group of Control (39.59%, and 42.45%) and SDS-100 (44.40% and 34.86%), the relative abundance of Cupriavidus increased to 84.06% and 59.45% in the group of SDBS-200 and SDS-200, respectively. Enzyme activity assays proved that the nitrite reductase (NiR) relative activity of aerobic denitrification was suppressed by both SDBS and SDS. The increase in the SDS concentrations (from 0 to 50mg/L) resulted in sharp growth of the nitrate reductase (NR) relative activities (from 100% to 146.86%). These findings demonstrated that SDBS and SDS affected aerobic denitrification efficiency of the aerobic denitrifiers by changing its microbial community structure and enzyme activity. PRACTITIONER POINTS: SDS strengthened aerobic denitrification at low concentration, but the aerobic denitrifiers were inhibited in SDBS. The variation of community structure played a vital role in the aerobic denitrification system. The enzyme activity was seriously affected by SDBS and SDS. Microorganisms and enzyme activity were synergistically involved in the aerobic denitrification.

Visualizing in-situ emulsification in porous media during surfactant flooding: A microfluidic study

HypothesisIt is well recognized that crude oil could be emulsified during surfactant flooding process, and recently such an in-situ emulsification was found practically helpful for enhanced oil recovery (EOR). However, no direct proofs are reported yet to unravel how emulsion is formed in porous media and how important to increasing oil recovery factor due to unavailability to visualize the emulsification process, thus it is desirable to verify visibly the formation of emulsion in porous media and the contribution of emulsification to EOR process. ExperimentsTwo types of microfluidic chips with heterogeneous and homogeneous pore geometries respectively were employed to simulate the underground oil reservoir environment. Sodium dodecylbenzenesulfonate (SDBS) was selected as a model surfactant, and its aqueous solution was injected into the paraffin oil-saturated microchip to mimic the displacing process. A series of tests were conducted by varying SDBS concentration, electrolyte content, injection rate, and pore-scale snapshots were captured for qualitative and quantitative analysis of in-situ emulsification during the surfactant flooding. FindingsBoth oil-in-water (O/W) and water-in-oil (W/O) emulsions are formed in microchips during the surfactant flooding. Increasing SDBS concentration, migration distance, injection rate, or addition of electrolyte tends to form smaller O/W particles through snapping action at pore throat, and vice versa. Smaller size endows oil with a better mobility to go through the pore throat, and up to 24% extra emulsion can be achieved through emulsification entrainment; bigger droplets can block the dominant paths, thus improving sweep efficiency and increasing oil recovery factor up to 30% compared to waterflooding. Furthermore, W/O emulsification was found to be a time-dependent process influenced by SDBS concentration, and oil was recovered by diffusing surfactant solution into oil phase and replacing the oil-occupied space in porous media.

Ultralight, Structurally Stable Electrospun Sponges with Tailored Hydrophilicity as a Novel Material Platform.

Sponges based on short electrospun fibers have received significant attention due to their ultrahigh porosity, lightweight, and multifunctional characteristics. In particular, polyimide (PI) sponges have been researched due to their exceptional mechanical properties and thermal stability. Nevertheless, a number of sponges, including PI, are usually hydrophobic and synthesized in toxic, nonwater solvents (e.g., 1,4-dioxane). Conversely, hydrophilic sponges disintegrate upon contact with water. Here, we suggest a new strategy to fabricate PI sponges in water by introducing a suitable surfactant, sodium dodecylbenzenesulfonate (SDBS) (sPI sponges). With less than 1 wt % of SDBS with respect to PI short fibers, they can be homogeneously dispersed in water and mixed well with poly(amic acid) (PAA) solution. The synthesized sponge, depending on the concentration of SDBS, showed hydrophilic properties and substantial water uptake above 5000%. The hydrophilic properties of the sponges, which are not common, and the preparation from aqueous solution introduce new research opportunities. Such hydrophilic sponges are particularly special because they do not swell in contact with water, which makes them dimensionally stable. The methods presented here can serve as a milestone for the future development of various kinds of hydrophilic sponges applied for various applications, ranging from tissue engineering to oil/water separation.