Motor Oil Removal Research Articles

Synthesis and application of dual-functional sorbent SBA-15-Fe3O4-PDA-ODA for removing both water soluble and insoluble pollutants

In this study, inorganic-organic hybrid sorbent SBA-15-Fe3O4-PDA-ODA with functional groups having affinity for both water-soluble and insoluble pollutants was synthesized for treatment of wastewater where Malachite Green (MG) dye and motor oil coexist. In order to enhance the specific interactions between the sorbent and dye via functional groups of polydopamine (PDA), Fe3O4 nanoparticles were encapsulated with SBA-15 and surface functionalization with PDA was accomplished and then the surface of Fe3O4-SBA-15-PDA was modified with octadecylamine (ODA) to remove the oil present in the same environment with dye. While the SBA-15-Fe3O4-PDA-ODA directed to the aqueous phase by magnet provided MG removal thanks to the hydrophilic groups of PDA, it provided motor oil removal thanks to hydrophobicity of ODA when directed to the oil phase. 99.20 % dye removal and 9.24 g/g oil adsorption capacity were achieved from the environment where oil and dye were present together. Besides, the adsorption of MG on Fe3O4-SBA-15-PDA was searched at various pH, dye concentration, adsorbent dosage, and temperature in order to propose optimum experimental conditions for removal of dye and maximum adsorption capacity was determined as 95.83 mg g−1 at optimum conditions (10 mg adsorbent, 10 mg L−1 MG concentration, pH 9). Interaction mechanism between dye and Fe3O4-SBA-15-PDA was explained by studying the adsorption behavior of sorbent derived from the isotherm and kinetic results. The sorbents were characterized by FT-IR, XRD, SEM, N2-adsorption/desorption, water-contact-angle, and VSM measurements. SBA-15-Fe3O4-PDA-ODA sorbent was tested for three successive adsorption cycles for both dye and oil and eventuated insignificant loss in activity when they were recycled. Easy and low-cost fabrication protocol, controllable removal ability of dye and oil will facilitate its versatility in environmental cleanup process for water soluble and insoluble pollutants.

Use of welding powder as a low‐cost adsorbent for waste motor oil removal

AbstractWaste motor oil (WMO), which has no stable form or structure, causes major environmental problems and damage to the ecosystem once it is disposed to the environment. Because of the high toxicity of contents in such effluent, it must be treated before being discharged into the receiving environment. In recent years, the valorization and the use of waste materials to remove toxic pollutants is of great importance to researchers and diverse industries. In this study, the usability of waste welding powder (WWP) as an adsorbent for waste oil removal was investigated. For this purpose, investigating the usability of material, which is generated as industrial waste, in wastewater treatment will lead to the evaluation of waste. The effects of temperature, pH, WWP amount, and initial WMO amount were investigated. According to the adsorption studies, 1 g WWP/L of the processed adsorbent was able to effectively remove 95.05% of WMO (100 mg) at a pH of 2 at 30°C. Stereo microscopy images showed a large amount of oil adsorbed on the WWP surface. The different WWP properties were determined by adsorption isotherm (Harkins–Jura), kinetic (pseudo‐second order), and thermodynamic (ΔG: −5.1 kJ mol–1) experiments. It is thought that WWP, which is a low‐cost and waste material, can be used as a promising adsorbent in WMO removal.

Biossurfactant production by isolated bacteria from petroleum industry’s effluent targeting bioremediation

In this study, bacterial strains from the Bacillus genus were isolated from residual effluents from treatment unit of a Petroleum Factory to produce a biosurfactant, aiming the bioremediation of oil-contaminated soils. Five strains were selected to perform fermentation tests. Results showed that the strain LUB P1 presented a lipopeptide with excellent properties, which reduced the surface tension to rates below 30 mN/m. The bacteria were genetically identified as a species belonging to the Bacillus subtilis. Characterization of the biosurfactant confirmed that the main component is surfactin, with a critical micellar concentration (CMC) value of 15 mg.L−1 and high stability to temperature, salinity, and pH variations. In addition, showed low toxicity compared to synthetic surfactants. Bioremediation tests indicated motor oil removal efficiency of over 80% on the temperature of 60 °C in its CMC, presenting excellent properties for the application in bioremediation.

Analysis of the surfactant properties of Eichhornia crassipes for application in the remediation of environments impacted by hydrophobic pollutants

The invasive aquatic plant Eichhornia crassipes may enable the generation of novel compounds with aggregate value for use in bioremediation processes. Thus, the surfactant properties of the plant extract were investigated. The critical micelle concentration (CMC) of the extract was 1.4 ± 0.1 g/L and the surface tension at this point was 25.84 ± 0.7 mN/m. The extract proved to be stable and non-toxic to the bioindicators evaluated. The emulsification index was higher than 65.00 ± 1.8% for motor oil. The chemical characterisation suggested that the structure of the extract was formed by an unsaturated fatty acid. The plant extract was capable of dispersing 100% of oil in seawater. The motor oil removal from sand with the plant extract at twice the CMC reached values around 68.04 ± 0.7% both in the kinetic assay and in the static assay using packed columns. The removal of heavy metals reached rates of around 40.00 ± 2.6%. The plant-derived surfactant clearly demonstrated viability regarding its use as a biotechnological additive for environmental remediation processes. • Surfactant properties of Eichhornia crassipes plant extract were investigated. • The plant biosurfactant proved to be stable and non-toxic to the bioindicators. • The biosurfactant emulsified 65% of motor oil and removed 40% of heavy metals. • The plant biosurfactant was characterized as an unsaturated fatty acid. • The plant biosurfactant dispersed 100% of oil and removed 67% of oil from sand.

Biosurfactant as an Environmental Remediation Agent: Toxicity, Formulation, and Application in the Removal of Petroderivate in Sand and Rock Walls

The exploitation and transportation of petroleum products are important reasons for environmental concern since they are the major causes of accidents involving oil spills. Therefore, the biosurfactant produced by the bacterium Bacillus cereus UCP1615 was applied in the removal of motor oil from sand and stones from coastal regions. Bioassays carried out with the microcrustacean Artemia salina and three vegetables' seeds showed that the biosurfactant has reduced toxicity. The application of the biosurfactant in crude and isolated form, as a removal agent, was carried out in static and kinetic tests using sand contaminated with motor oil, in packed columns, and in flasks under orbital agitation, respectively. The results showed that the biosurfactant removed 63.0 ±2.1% of the hydrocarbon in the static test and 84.0 ±2.2% in the dynamic test. In tests using rock wall samples, the removal rates reached 69.0 ±2.0%. Conservation tests carried out during 120 days demonstrated that the surfactant activities were maintained, especially in the presence of the preservative potassium sorbate. The B. cereus biosurfactant has proven to be a biocompatible, effective, and stable alternative for applications in environments contaminated with hydrophobic compounds and can be industrially stored for application in the event of possible environmental disasters.

Motor oil removal from water by continuous froth flotation: The influence of surfactant structure on interfacial adsorption and foam properties

The influence of the chemical structure of three surfactants, anionic extended surfactant Alfoterra® C145–8PO (ALF), anionic methyl ester sulfonate (MES), and cationic cetyltrimethyl ammonium bromide (CTAB), on the adsorption and foam characteristics relating to effectiveness at reduction of motor oil in a continuous froth flotation system. All surfactants were chosen based on having the similar number of carbon atoms in alkyl chain. So the effects of the different head group and the existence of a polypropylene oxide in the ALF’s structure on the surface activity and motor oil removal could be elaborated. The results demonstrated that CTAB, having strongest positively charged head group with the shortest tail length, provided the highest diffusivity, foamability, and foam stability, leading to the highest enrichment ratios of motor oil and surfactant. Conversely, ALF, having the largest molecular size and the longest tail length, gave the lowest diffusivity and foam properties. Hence, it exhibited the highest motor oil removal and surfactant recovery with the lowest enrichment ratios of both motor oil and ALF. The added packing media with 50% packing volume augmented the residence time of the rising air bubbles, enhancing the motor oil removal by about 16%, 15%, and 24% for the ALF, MES, and CTAB, respectively.

Adsorptive removal of oil spill from sea water surface using magnetic wood sawdust as a novel nano-composite synthesized via microwave approach.

Water pollution by oil is a serious environmental problem. Developing new generation of benign adsorbents satisfying several criteria required for real practical application is of great need. This work introduces an effort in this direction, by utilizing a facile synthesis of wood sawdust coated magnetite nanoparticles functionalized stearic acid (WSD@Fe3O4NPs/SA) as a novel nano composite along with its precursor WSD@Fe3O4NPs. SA was covalently bonded to the precursor by amide bond formation via the interaction with the silylating agent 3-aminopropyltrimethoxysilane (3-APTS). This mode of binding is more stronger than the conventional ester bond. Fourier transform infrared (FT-IR), X- ray powder diffraction (XRD), Scanning electron microscope (SEM) and Transmittance electron microscope (TEM) were employed for characterization and follow up the synthesis process. Application of the newly synthesized magnetic nano composite adsorbent under optimized parameters of contact time (min) and composite dosage (g) reveal high removal capacity values (g/g) evaluated to be 28.32g/g, 5min and 0.1g for used motor oil removal and 41.22g/g, 10min and 0.1g for crude oil. The high removal efficiency exhibited by WSD@Fe3O4NPs/SA was mainly argued to the long hydrocarbon chain of SA moiety and additional ـــ (CH2)3 ـــ groups incorporated 3-ATPS. Moreover, Analysis of the oil adsorption experimental equilibrium data were well fitted with Freundlish model with correlation coefficients r2 = 0.9788 and 0.9896 for used motor oil and crude oil, respectively. The kinetic data were correlated using two kinetic models and the results were in harmony with pseudo-second order.

Production and Application of Biosurfactant Produced by Bacillus Licheniformis Ali5 in Enhanced Oil Recovery and Motor Oil Removal from Contaminated Sand.

The present study describes the production of biosurfactant from isolate B. licheniformis Ali5. Seven different, previously-reported minimal media were screened for biosurfactant production, and two selected media were further optimized for carbon source. Further, various fermentation conditions such as (pH 2–12, temperature 20–50 °C, agitation speed 100–300 rpm, NaCl (0–30 g·L−1) were investigated. The partially purified biosurfactant was characterized by Fourier transform infrared spectroscopy (FTIR) and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS) and found a lipopeptide mixture, similar to lichenysin-A. Biosurfactant reduced surface tension from 72.0 to 26.21 ± 0.3 and interfacial tension by 0.26 ± 0.1 mN·m−1 respectively, biosurfactant yield under optimized conditions was 1 g·L−1, with critical micelle concentration (CMC) of 21 mg·L−1 with high emulsification activity of (E24) 66.4 ± 1.4% against crude oil. Biosurfactant was found to be stable over extreme conditions. It also altered the wettability of hydrophobic surface by changing the contact angle from 49.76° to 16.97°. Biosurfactant efficiently removed (70-79%) motor oil from sand, with an efficiency of more than 2 fold as compared without biosurfactant (36–38%). It gave 32% additional oil recovery over residual oil saturation upon application to a sand-packed column. These results are indicative of potential application of biosurfactant in wettability alteration and ex-situ microbial enhanced oil recovery.

Effect of consecutive SiCl4 and hydrophobic molecule modification of cotton cloth for fresh oils and used oils removal

The aim of this study was to enhance the hydrophobicity of cotton cloth using silicon tetrachloride (SiCl4) combined with water-repellent agents 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS), dimethyldichlorosilane (DMDCS), and stearic acid (SA) for cooking oil and motor oil removal. The cotton cloths were firstly pretreated with SiCl4, at this stage the SiO2 was formed on the cotton cloth surfaces. Secondly, the untreated and SiCl4-treated cotton cloths were separately modified with POTS and DMDCS by chemical vapour deposition and with SA by chemical immersion methods. The surface morphology of the cotton cloths after pretreatment with SiCl4 followed by water-repellent agents was investigated by SEM and EDS techniques. The surface charge of the treated and untreated cotton cloths was also analysed by zeta potential measurement over a pH range of 3–11. The contact angle and the tensile properties of the cotton cloths under various treatment conditions were also investigated, and comparisons were carried out. The results of this study showed that the hydrophobicity of cotton cloth modified by water-repellent agents increased by SiCl4 pretreatment. Untreated and treated cotton cloths were applied to remove used cooking oil and motor oil, and the results were compared with those for the removal of fresh cooking oil and motor oil. The SiCl4 pretreatment prior to bonding with water-repellent agents clearly showed that the POTS–SiCl4 treated cotton cloth performed with the maximum efficiency with regard to oil removal, followed by DMDCS–SiCl4 treated and SA–SiCl4 treated cotton cloths.

Recovery of contaminated marine environments by biosurfactant-enhanced bioremediation.

The need to remediate areas contaminated by petroleum products has led to the development of novel technologies for treating such contaminants in a non-conventional manner, that is, without the use of chemical or physical methods. Biosurfactants are amphipathic biomolecules produced by microorganisms that can be used in bioremediation processes in environments contaminated by petroleum products due to their excellent tensioactive properties. The aim of the present study was to produce a biosurfactant from Pseudomonas aeruginosa UCP 0992 cultivated in 0.5% corn steep liquor and 4.0% vegetable oil residue in a 1.2-L bioreactor employing a central composite rotatable design to optimize the cultivation conditions for maximum yield. The best results were achieved with aeration rate of 1.0 vvm and 3.0% inoculum at 225 rpm for 120 h, resulting in a surface tension of 26.5 mN/m and a biosurfactant yield of 26 g/L. Kinetic and static assays were then performed with the biosurfactant for the removal of motor oil adsorbed to sand, with removal rates around 90% and 80%, respectively, after 24 h. Oil degradation experiments with the bacterium and the combination of the bacterium and biosurfactant were also conducted to simulate the bioremediation process in sand and seawater samples (duration: 75 and 30 days, respectively). In both cases, oil degradation rates were higher than 90% in the presence of the biosurfactant and the producing species, indicating the potential of the biomolecule as an adjuvant in petroleum decontamination processes in the marine environment.

Application of biosurfactant produced by an adaptive strain of C.tropicalis MTCC230 in microbial enhanced oil recovery (MEOR) and removal of motor oil from contaminated sand and water

Microbial enhanced oil recovery (MEOR) represents the use of microorganisms or their products to recover remaining oil trapped up in oil reservoirs. In this study adaptive strain C. tropicalis MTCC230 was used to determine its suitability in MEOR. Biosurfactant produced from an adaptive strain C. tropicalis MTCC230 was characterized as lipopeptide surfactin by Near IR, FTIR spectrum and HPLC and mass spectroscopy analysis. It can significantly reduce the surface tension 72 mN/m to 32 mN/m, with the critical micelle concentration (CMC) of 32.5 mg/l and B. subtilis MTCC2423 used as a standard surfactin (Biosurfactant) producing strain for comparative study. It shows stable Physiochemical properties under the extreme pH(2–12), temperature(30°C-90 °C) and salinity(2%–10%) that promote its potential use in enhanced oil recovery. Oil spreading method and soil washing analysis confirmed it suitability to remove the hydrocarbon contaminants from water and soil. Laboratory scale sand pack column saturated with four stroke engine oil resulted ∼39.80% additional oil recovery (AOR), suggesting its suitability for commercial use in microbial enhanced oil recovery (MEOR) in oil reservoirs.

Removal of motor oil by continuous multistage froth flotation: Effect of operational parameters

ABSTRACTA continuous multistage froth flotation column was employed to remove motor oil from water at a low concentration (500 mg/L) using an extended surfactant – branched alcohol propoxylate sulphate sodium salt (C14-15–8PO–SO4–Na) – as a frother. The highest separation efficiency (97% motor oil removal with the enrichment ratio of 16 for motor oil) was obtained at a foam height of 60 cm, an air flow rate of 40 L/min, a feed flow rate of 60 mL/min, a surfactant concentration of 0.3% (w/v), and an NaCl concentration of 1.5% (w/v). The process performance increased with increasing tray number but beyond 4 trays, the system could only offer lower concentrations of motor oil and surfactant in the effluent.

Application of bacterial and yeast biosurfactants for enhanced removal and biodegradation of motor oil from contaminated sand

Background: This study investigated the potential application of two biosurfactants for enhanced removal capability and biodegradation of motor oil contaminated sand under laboratory conditions. The biosurfactants were produced by the yeast Candida sphaerica and by the bacterium Bacillus sp. cultivated in low-cost substrates. The ability of removing motor oil from soil by the two biosurfactants was identified and compared with that of the synthetic surfactants Tween 80 and Triton X-100. Results: Both crude and isolated biosurfactants showed excellent effectiveness on motor oil removal from contaminated sand under kinetic conditions (70 - 90%), while the synthetic surfactants removed between 55 and 80% of the oil. A contact time of 5-10 min under agitation seemed to be enough for oil removal with the biosurfactants and synthetic surfactants tested. The crude and the isolated biosurfactant from C. sphaerica were able to remove high percentages of motor oil from packed columns (around 90%) when compared to the biosurfactant from Bacillus sp. (40%). For the degradation experiments conducted in motor oil contaminated sand enriched with sugar cane molasses, however, oil degradation reached almost 100% after 90 d in the presence of Bacillus sp. cells , while the percentage of oil degradation did not exceed 50% in the presence of C. sphaerica . The presence of the biosurfactants increased the degradation rate in 10 - 20%, especially during the first 45 d, indicating that biosurfactants acted as efficient enhancers for hydrocarbon biodegradation. Conclusions: The results indicated the biosurfactants enhancing capability on both removal and rate of motor oil biodegradation in soil systems.

Absorption of a linear (L2) and a cyclic (D4) siloxane using different oils: application to biogas treatment

Hydrophobic volatile methyl siloxanes (VMS), such as hexamethyldisiloxane (L2) and octamethylcyclotetrasiloxane (D4), present a low solubility in water. An alternative treatment by absorption into hydrophobic absorbents was therefore studied. For this purpose, three different absorbents, motor oil, cutting oil and a water-cutting oil mixture, were selected with the aim of re-using a waste product. The set of experiments was carried out in a bubble column, where parameters such as inlet concentration, residence time and temperature were studied. The best performance for the removal of both siloxanes, in terms of absorption capacity, was observed for motor oil, particularly for D4. In fact, motor oil removal efficiency for D4 was 80%, whereas for L2 it was 60%, indicating that D4 is more easily absorbed than L2. In the case of water-cutting oil, this showed a mass transfer enhancement from the gas phase to the liquid phase compared with water alone. Furthermore, a removal efficiency of 70% was observed for D4, showing that the addition of an oil fraction to a water system improves the absorption of VMS. These results show that VMS absorption into oils could be a promising way to achieve their abatement.

Screening of Pseudomonas species for biosurfactant production using low-cost substrates

Abstract In the present study, four species of Pseudomonas ( P. cepacia, P. acidovorans, P. picketti and P. fluorescens ) were cultivated in different low-cost substrates and compared with regard to biosurfactant production. Surface tension was used as a preliminary screening standard for potential biosurfactant bacteria. The best result was obtained with P. cepacia grown in mineral medium supplemented with 2.0% corn steep liquor and 2.0% soybean waste frying oil for 144 h at 30 °C and 200 rpm. Kinematic studies on microorganism growth and biosurfactant production were performed. Surface tension of the medium was reduced to 27.57 mN/m at the end of the cultivation, yielding 5.2 g/L of isolated biosurfactant. Tests under extreme conditions of pH, temperature and NaCl indicated the stability of the biosurfactant for use in the treatment of oil-contaminated environments. The critical micelle dilution of the biosurfactant was determined and its use in the removal of motor oil from clay soil demonstrated rates greater than 80%. Washing experiments involving rocks and oily surfaces contaminated with motor oil demonstrated greater than 80% recovery rates. The crude biosurfactant was capable of dispersing approximately 80% of oil droplets in seawater and proved to be non-toxic to indigenous marine microbiota. The crude biosurfactant demonstrated no toxicity against seeds of Brassica oleracea or the microcrustacean Artemia salina employed as a bioindicator. The present findings indicate the application potential of the biosurfactant produced by P. cepacia in the oil industry as a complement to remediation processes involving contaminated soil and water.

Motor oil removal from water by continuous froth flotation using extended surfactant: Effects of air bubble parameters and surfactant concentration

The objective of this study was to correlate the air bubble parameters in a flotation column and the surfactant concentration to the efficiency of motor oil removal from water by continuous froth flotation. C 14–15(PO) 5SO 4Na (branched alcohol propoxylate sulfate, sodium salt) was used to form microemulsions with motor oil. From the microemulsion phase diagram, the minimum surfactant concentration, known as the critical microemulsion concentration (CμC), to form a Winsor Type III microemulsion, was preliminarily selected for the froth flotation experiments. An increase in surfactant concentration was found to reduce the size and rising velocity of air bubbles in the froth flotation column, whereas the specific surface area, bubble surface area flux, bubble number flux, and residence time of the air bubbles increased with increasing surfactant concentration. The maximum removal of both motor oil and surfactant was found to correspond to the CμC. Beyond the CμC, the oil removal decreased with increasing the surfactant concentration because increasing the micelle concentration results in increasing oil stabilization.

Microemulsion Formation and Detergency with Oily Soil: IV. Effect of Rinse Cycle Design

AbstractThe objective of this work was to apply a microemulsion‐based formulation for the removal of motor oil in laundry detergency at low salinity. To produce the desired phase behavior, three surfactants were used: alkyl diphenyl oxide disulfonate (ADPODS), sodium dioctyl sulfosuccinate (AOT) and sorbitan monooleate (Span 80). The mixed surfactant system of 1.5% ADPODS, 5% AOT and 5% Span 80 (13 parts ADPODS, 43.5 parts AOT, and 43.5 parts Span 80 of the total actives) was found to form a middle phase microemulsion (Type III) at a relatively low salinity of 2.83% NaCl. When this formulation was diluted, detergency performance increased with increasing total surfactant concentration and leveled off above about 0.1% total actives on the three types of fabrics studied (pure cotton, 65/35 polyester/cotton blend, and pure polyester). Detergency was found to improve with increasing hydrophilicity of the fabric with cotton being cleanest after washing and polyester the most difficult to clean. To achieve a specified oil removal, less rinse water can be used if a higher number of lower‐volume rinses are employed. An interesting characteristic of microemulsion‐based formulations is that a substantial fraction of oil removal occurs during the rinse cycle. In this work, this removal is shown to be due to the low oil/water interfacial tension during initial rinsing and is therefore strongly correlated to residual surfactant concentration in the rinse steps. As a result, the number of rinses and the volume of water per rinse can profoundly affect detergency in these systems.

Governing factors for motor oil removal from water with different sorption materials

This paper has been focused on the sorbent efficiency for motor oil removal from water. Two types of sorbents were investigated: organic and inorganic. Natural wool fibers (NWFs) and recycled-wool-based nonwoven material (RWNM)) were tested as organic type of sorbents. Sepiolite, bentonite and zeolite have been chosen as representative inorganic sorbents. Sorption was carried out in batch sorption system. Efficiency of oil removal was determined by measuring the oil concentration before and after the sorption process. Extractive-gravimetric method and refractive index determination have been applied as analytical methods for determination of oil concentration in water. Governing factors for sorbent efficiency were proposed, analysed and compared. It was concluded that sorption process is mostly affected by mass of sorbent, sorption time, temperature and pH value of water. NWFs, which were the most efficient sorbent showed maximal efficiency and maximal sorption capacity: 0.1 g of NWFs after 10 min at 20 °C and pH 8.00 sorbed 3.3 g of motor oil from 300 mL of water polluted with 4.5 g of motor oil. Maximal efficiency for all sorbents investigated was reached after 30 min of sorption processes, it was 95.0% for NWF, 43.0% for NRWM, 20.7% for sepiolite, 19.6% for bentonite and 21.2% for zeolite. Physical adsorption onto all sorbents is a favorable process (sorption efficiency decrease with increasing temperature) while sorption onto bentonite and zeolite is a result of both physical adsorption and chemisorption (sorption efficiency increase with increasing temperature, up to 80 °C).

Linker‐modified microemulsions for a variety of oils and surfactants

AbstractPreviously, we reported on the use of hydrophilic and lipophilic linker molecules to enhance the solubilization capacity of chlorinated hydrocarbons using sodium dihexyl sulfosuccinate (SDHS). In this work we extend the use of linker molecules to a wider range of oils and surfactants. The data show that the linker effect works for all the systems studied and that linker‐based systems are even more economical than surfactant‐only systems for more hydrophobic oils. Using a more hydrophobic surfactant, such as sodium bis(2‐ethyl)dihexyl sulfosuccinate (Aerosol‐OT), requires a formulation enriched with a hydrophilic linker, whereas the formulation for the more hydrophilic SDHS requires the use of a more lipophilic linker. By considering the properties and appearance of the formulation before contacting with the oil, and by evaluation the coalescence dynamics, we found that hydrophilic linker‐rich formulations were preferred. These formulations were tested as fabric pretreatments for removing motor oil and hexadecane from cotton, and as flushing solutions for glass bead columns contaminated with these oils. The cleaning performance of these linker‐based systems was superior to common surfactant and pretreatment formulations in the detergency tests, achieving more than 80% removal of motor oil and hexadecane trapped in the packed‐column flushing tests.

Microemulsion formation and detergency with oily soils: II. Detergency formulation and performance

AbstractIn part I of this series (J. Surfact. Deterg. 6, 191–203, 2003), the mixed surfactant system of sodium dioctyl sulfosuccinate (AOT), alkyl diphenyl oxide disulfonate (ADPODS) and sorbitan monooleate (Span 80) was shown to form Winsor type I and type III microemulsions with hexadecane and motor oil. In addition, high solubilization and low interfacial tension were obtained between the oils and surfactant solutions both in the supersolubilization region (Winsor type I system close to type III system) and at optimal conditions in a type III system. In the present study, this mixed surfactant system was applied to remove oily soil from fabric (a polyester/cotton blend), and detergency results were correlated to phase behavior. Dynamic interfacial tensions were also measured between the oils and washing solutions. In the supersolubilization and in the middle‐phase regions (type III), much better detergency performance was found for both hexadecane and motor oil removal than that with a commercial liquid detergent product. In addition, the detergency performance of our system at low temperature (25°C) was close to that obtained at high temperature (55°C), consistent with the temperature robustness of the microemulsion phase behavior of this system.