Hexadecane Research Articles

Surface-active ionic liquids as lubricant additives to hexadecane and diethyl succinate

The effectiveness of surface-active ionic liquids (SAILs) as lubricant additives in both polar and apolar base liquids has been investigated on stainless steel surfaces at both macroscale and nanoscale. The SAILs studied are composed of trihexyltetradecylphosphonium ([P6,6,6,14]+) cations paired with either dioctyl sulfosuccinate ([AOT]-) or dodecyl sulphate ([DS]-) anions. The polar and apolar base liquids used to dilute the SAILs are diethyl succinate ((CH2CO2Et)2) and hexadecane (HD), respectively. The friction coefficients of pure [P6,6,6,14] [AOT] and [P6,6,6,14] [DS] are up to ∼80 % lower than those of (CH2CO2Et)2 and HD. Remarkably, diluted solutions containing as little as 5 wt% SAIL in either (CH2CO2Et)2 or HD exhibit lubricity comparable to that of pure SAILs, revealing their excellent potential as lubricant additives. The high lubricity of the SAIL solutions in both (CH2CO2Et)2 and HD is attributed to the adsorption of anions onto the positively charged stainless steel surface, resulting in the formation of a robust boundary layer that reduces surface contact and facilitates smooth sliding. These insights aid the development of advanced, cost-effective lubricant additives, with potential applications across various industrial sectors.

Effect of Pigment-Acrylic Binder Ratio on the Surface and Physical Properties of Resin Finished Leather

The current study attempts to investigate the surface phenomenon and physical characteristics of leather finished with brown pigment and different types of acrylic binders. Using the contact angle measurements of three different liquids on the above finished leathers and films, the surface energy and work of adhesion were evaluated. The pigment to acrylic binder ratio (PABR) for best adhesion of finish film on the leather surface was optimized using the contact angle goniometer. Different types of acrylic binder films were coated and their surface behaviour was studied. The crust leather was coated with different types of pigment-acrylic binder (Very Soft, Soft and Medium Soft) finish formulations. The contact angle of both the acrylic films and the PABR finished leathers were measured against Water, Dimethyl sulfoxide (DMSO) and Hexadecane (HD). According to the study’s results, the surface properties of finished leather were directly related to the degree of wetting. The PABR was found to be effective at 1:3 for very soft binder, 1:2.5 for soft, 1:2 for medium soft binders due to higher contact angle and lower surface energy values (γsv). At 1:3 and 1:2.5, the contact angle of very soft and soft binder leather was 82.62° and 83.45° and for medium soft binder it was 82.67° at 1:2 ratio. The surface energy values of optimized PABR of very soft binder (1:3) was 28.29 (mN/M), soft binder (1:2.5) was 27.50 (mN/m) and medium soft binder (1:2) was 29.27 (mN/m). The optimized PABR work of adhesion values of very soft binder, soft binder and medium soft binder was 82.15 (mJm-2), 81.11 (mJm-2), 82.09 (mJm-2). In order to correlate the observed surface properties with leather finish properties, finished leathers were tested for finish adhesion, vamp flexing value, water vapour permeability, wet and dry rub fastness. According to the water vapour permeability, soft and medium binder showed good permeation due to the uncovering of nanopores. But the adhesion, grain crack resistance and grain smoothness were higher in the case of the soft binder. Overall leather properties divulges that the pigment to binder ratio and the type of binder plays an important role in surface properties of the finished leather. This study enables us to determine the optimal PABR for effective finish properties to meet the required leather standards for various usage, as well as better utilisation of finishing chemicals.

Shape-stabilization of organic phase change materials as mechanically stable silica boards with high latent heats synthesized via sol-gel route

Monolithic shape-stabilized phase change materials (ss-PCM) are of great interest for energy-saving construction materials, solar-water heating systems and passive cooling systems of batteries and photovoltaic cells. However, the application range of ss-PCMs is currently limited by either low mechanical stabilities or low heat storage capacities. Therefore, we recently developed ss-PCMs based on silica and butyl stearate (BS) with high compressive strengths (1.2 MPa, 10 °C), but only moderate latent heats (∼100 J/g). Here, we focus on validating the applicability of our porogen-assisted sol-gel process to other organic PCMs apart from butyl stearate. To increase the latent heat of ss-PCMs, we create a mixture of 70% hexadecane (HD) or octadecane (OD) with 30% BS and combine this PCM mixture with our novel-sol-gel route to synthesize ss-PCMs with high compressive strengths (1.2 MPa, 5 °C) as well as high latent heats (160 J/g). Due to the well-interconnected silica matrix confining the paraffins, the ss-PCMs have 70% higher thermal conductivities (0.43 W/mK, 5 °C) than pure paraffins, high shape-stabilities (∼100%), high PCM loadings (83 wt%), and high chemical and long-term stabilities (>3000 thermal cycles). Moreover, they are thermally stable up to ∼170 °C with PCM melting points of 17 °C and 22 °C. We also synthesize ss-PCMs with pure polyethylene glycol 600 (PEG600) and pure acetamide (Ac) to analyze the effect of non-paraffinic PCMs on the physicochemical properties of ss-PCMs. These ss-PCMs have a ∼30% lower latent heat than expected because the PCM either reacts strongly by hydrogen bonding with the silica (PEG600) or was chemically degraded under the basic conditions during gelation (Ac). In contrast to the low compressive strength of shape-stabilized PEG600 (35 kPa, 5 °C), the ss-PCMs based on Ac have high compressive strengths (9.6 MPa, 5 °C). Moreover, they are translucent above the PCM melting point due to a nanoscopic silica matrix. The high supercooling effect (37 °C) and the moderate long-term stability (3000 thermal cycles, 20% lower latent heat) of shape-stabilized Ac restrict its application to special, glassy materials.

Effective removal of hydrogen sulfide from landfill gases using a modified iron pentacarbonyl desulfurization agent and the desulfurization mechanism

High-efficiency desulfurization is key to the recovery and use of landfill gases. In this study, a nano‑iron oxide desulfurization agent modified from iron pentacarbonyl was prepared in n-decane (DE) and hexadecane (HE) by ultrasonic disruption without any supporting materials and its hydrogen sulfide removal ability and desulfurization mechanism were studied. The yield of the desulfurization agent was higher when HE was used as the solvent; however, the products generated by both solvents had the same crystal type and similar properties. The efficiency of the desulfurization agent was significantly improved at 150–200 °C, exceeding 90% at 150 °C with single sulfur production. The maximum sulfur adsorption capacity of the desulfurization agent produced after 3 h of DE ultrasonic treatment at 200 °C (DE3) was 492 mg/g (desulfurization efficiency = 97.33%), while that of the agent produced after 3 h of HE ultrasonic treatment at 250 °C (HE3) was 522 mg/g (desulfurization efficiency = 99.30%). The desulfurization reaction involved both chemical adsorption and catalytic decomposition and the catalytic decomposition reaction rate was lower than that of chemical adsorption. Therefore, the more FexSy produced in the chemical adsorption process, the better catalytic performance was.

A facile approach preparing PMMA nanospheres through in-situ surfactant miniemulsion photopolymerization under green LED irradiation

Herein, a facile method combining in-situ generation of potassium oleate (KOA) and miniemulsion photopolymerization under green LED irradiation was proposed to prepare poly(methylmethacrylate) (PMMA) nanospheres. A miniemulsion containing methyl methacrylate (MMA) was prepared in situ, in which KOA as a surfactant was synthesized by the neutralization reaction of oleic acid (OA) and potassium hydroxide (KOH), and then miniemulsion photopolymerization occurred to obtain PMMA nanospheres under green LED irradiation. Emulsion stability test proved that the in-situ surfactant miniemulsion has higher stability than the preformed surfactant miniemulsion. The effect of surfactant amount and exposure time on photopolymerization was investigated. Furthermore, hexadecane (HD) and polyvinylpyrrolidone (PVP) were introduced into the polymerization system to avoid the adverse effect of Ostwald ripening and particle agglomeration respectively, and PMMA nanospheres with uniform sizes of ∼100 nm were finally prepared.

An energy dissipation tribometer to evaluate friction in boundary lubrication regime

A "parallel pendulum tribometer" is designed and developed to conduct experiments at lower sliding speeds (boundary lubrication regime). At such low speeds, the stiffness of the actuators and load cells in tribometers influence the contact stiffness. As a result, the experimental conditions at the contact get altered. The present tribometer overcomes these stiffness related issues. The tribometer is a highly underdamped system which results in a high resolution in the boundary lubrication regime. The energy dissipated at the contact is used to determine the frictional force. Experiments were conducted using two model lubricants, Hexadecane (HD) and Hexadecane+1%Stearic Acid (HDSA). HDSA was found to be more effective in reducing friction at lower sliding velocities when compared to HD.

The Influence of Oily Vehicle Composition and Vehicle-Membrane Interactions on the Diffusion of Model Permeants across Barrier Membranes.

In many instances, one or more components of a pharmaceutical or cosmetic formulation is an oil. The aims of this study were two-fold. First, to examine the potential of preferential uptake of one oily vehicle component over another into a model barrier membrane (silicone) from blended vehicles (comprising two from the common excipients isohexadecane (IHD), hexadecane (HD), isopropyl myristate (IPM), oleic acid (OA) and liquid paraffin). Second, to study the effect of membrane-vehicle interactions on the diffusion of model permeants (caffeine (CF), methyl paraben (MP) and butyl paraben (BP)) from blended vehicles. Selective sorption and partition of some oils (especially IHD and IPM) at the expense of other oils (such as OA) was demonstrated to take place. For example, the membrane composition of IHD was enriched compared to a donor solution of IHD-OA: 41%, 63% and 82% IHD, compared to donor solution composition of 25%, 50% and 75% IHD, respectively. Pre-soaking the membrane in IHD, HD or LP, rather than phosphate buffer, enhanced the flux of MP through the membrane by 2.6, 1.7 and 1.3 times, respectively. The preferential sorption of individual oil components from mixtures altered the barrier properties of silicone membrane, and enhanced the permeation of CF, MP and BP, which are typically co-formulated in topical products.

Isolation and characterization of halophilic bacterial consortium from seagrass, Jeddah coast, for the degradation of petroleum hydrocarbons and treatment of hydrocarbons-contaminated boat fuel station wastewater

The halophilic consortium enriched from seagrass present in Jeddah coast region, Saudi Arabia, potently degraded different petroleum hydrocarbons such as phenanthrene (PHE), fluorene (FLU), pyrene (PY) and hexadecane (HD) under saline condition (4%). The halophilic consortium recorded complete degradation of PHE and FLU up to 400 ppm. At 600 ppm of PHE and FLU, the consortium revealed 98% and 99% degradation in 10 days. Further increase in concentration to 800 ppm showed slight decline in the percent degradation of PHE (92%) and FLU (95%) by the halophilic consortium. Pyrene was selected as model compound from high molecular weight hydrocarbons recorded 84% and 78% degradation by the consortium at 50 ppm and 100 ppm in 8 and 10 days, respectively. The halophilic consortium revealed complete degradation of HD at 0.5% and 1% concentration under saline condition. The consortium was able to degrade 93% and 71% of HD at 1.5 and 2% concentration in 6 and 8 days under saline condition. Under different high saline conditions such as 8%, 12%, 16% and 20%, the halophilic consortium exhibited PHE (95%, 90%, 85%, 65%) and FLU (97%, 92%, 86%, 66%) degradation in 7, 10, 14 and 18 days. Addition of urea and yeast extract at high salinity enhanced the biomass production and reduced the time taken for degradation. The surface tension of the biosurfactant produced by the consortium was 36 ± 1 mN/m. The treatment of hydrocarbons-contaminated boat fuel station wastewater in continuous stirred tank reactor recorded 92% Chemical Oxygen Demand removal in 40 days. The potential halophilic strains present in the consortium responsible for petroleum hydrocarbon degradation were identified as Marinobacter, Rhodococcus, Ochrobactrum, Martelella, Pseudomonas, Stenotrophomonas and Sedimentibacter.

Ability of Mangrove Fungi in Biodegradation of Hexadecane

Oil pollution, especially in the marine environment, has become a serious environmental problem. Hexadecane (HXD) is a major alkane component and it is present in the aliphatic fragment of crude oil, which can be used by fungi as a sole carbon source. Biosurfactant which is produced by fungi facili tates HXD degradation. This study investigated the ability of mangrove fungi to be used as HXD and produce biosurfactant. The medium used to determine the ability of fungi to use hexadecane is MSM-HXD 2%, whereas Hua medium is used for determining the potential for producing biosurfactants. Biosurfactant production by fungi strains was indicated by oil displacement test, the reduction in surface tension and emulsion index. The results showed that 13 out of 16 species of fungi can use HXD as a sole carbon source. Inonotus radiatus LM 3020 is observed to be the most capable isolate to use HXD with a growth ratio of 6.0, and can produce biosurfactant with a positive oil displacement test (ODT) value whose minimum surface tension was 54.01 dyne/cm but the emulsion index was found to be zero.

Electrowetting of Hydrofluoroether Liquid Droplet at a Gold Electrode/Water Interface: Significance of Lower Adhesion Energy and Static Friction Energy.

We explored the electrowetting behavior of a hydrofluoroester solvent, Novec 7100 (Novec), as a liquid droplet on a Au(111) electrode in water (0.05 M KClO4). Comparison with the electrowetting of hexadecane (HD) highlighted the significance of the lower adhesion energy and static friction energy of Novec than those of HD. The electrode potential-dependent contact angle θ of a Novec droplet showed little hysteresis. When potentials were set by means of potential steps, a Novec droplet increased its θ at more positive potentials than the potential of zero charge (pzc) of the Au(111) electrode. We found that the key factor of the electrowetting behavior for Novec is its low adhesion energy and static friction energy. The static friction energy of the oils to the Au(111) electrode surface was evaluated by a comparative analysis of the potential dependence of the interfacial tension at the solid/water interface, ΔγS/W-E curve, calculated from electrochemical surface charge data and the experimental cos θ-E curve: 2.6 mN/m for HD and 0.95 mN/m for Novec. When Br- was added in the aqueous solution to allow its adsorption on the Au surface surrounding a Novec droplet, the potential of maximum cos θ was shifted to negative. Overall, although the Novec droplet showed a narrower range of θ change than a HD droplet, the Novec droplet seldom got stuck to the surface as far as potential step was used, reflecting the narrower plateau region of θ near the pzc. Also, the specific adsorption of a coexistent anion was a significant factor of θ. This work has featured the significance of a slippy droplet on an electrode surface, giving an impact on the technology of microfluid transportation control by electric potentials.

Waste Cooking (Palm) Oil as an Economical Source of Biodiesel Production for Alternative Green Fuel and Efficient Lubricant

Here, a cost-effective route for the preparation of biodiesel (BD) from waste cooking oil (WCO) as an alternative eco-friendly fuel and lubricant via catalytic transesterification process using simple base catalyst was demonstrated. Physical and chemical characterization based on FT-IR, 1H-NMR, and 13C-NMR spectroscopy reveals that free carboxylic acid functionality successfully alters to methyl ester of same hydrocarbon chain during the reaction. The BD was characterized by its physical, fuel characteristics including density, viscosity, acid value, flash point, pour point, and foaming tendency, and compared with existing diesel fuel in accordance with ASTM test standard. Prepared BD showed excellent fuel efficiency with higher flash (142 °C) and fire point (147 °C) than the existing diesel fuel. In order to use these synthetic biodiesel esters as advanced green lubricants, their lubrication behavior was tested and compared with hydrocarbon base oil hexadecane (HD). The macrotribological results showed the biodiesel significantly reduced the coefficient of friction by a maximum ~ 43% and specific wear rate ~ 71% in comparison with that of HD at variable applied load. The lubricating efficiency of prepared BD was found to be a similar trend in microtribometric experiments with reciprocating sliding motion under variable loads with similar contact pressure (Pm ~ 1.36–1.95 GPa) as demonstrated in macrotribological rotating motion. Due to polar nature of biodiesel, it deposits on the contact interface and provides a thick molecular film, which may be responsible for enhanced tribological behavior compared with pristine hydrocarbon oil.

Facile preparation of a slippery oil-infused polymer surface for robust icephobicity

This work concentrated on the fabrication of effective slippery liquid-infused porous surfaces (SLIPSs) to robustly resist ice adhesion by using facile method and smart composition. Firstly, poly(methyl methacrylate) (PMMA), polyhedral oligomeric silsesquioxane end-functionalized PMMA (POSS-ef-PMMA) and polydimethylsiloxane-blocked PMMA (PDMS-b-PMMA) were synthesized. Secondly, micro-sized pores arranged in a three-layer honeycomb-like array at a thickness of ca. 10 μm were elicited on each surface of these three cast polymer films by breath-figure (BF) method. After a separate infiltration of polydimethylsiloxane (PDMS), poly (hydrogenmethylsiloxane) (PHMS) and hexadecane (HD) into the porous matrixes, typical SLIPSs were formed. PDMS-b-PMMA matrix with preferential lipophilicity towards PDMS endowed the obtained SLIPS with better icephobicity. However, HD-induced SLIPSs performed the lowest sliding angles at 6° for 3 μL of water droplet, the lowest ice adhesional strength ranging from 40.8–46.3 kPa and the most robust anti-icing properties of resisting more than 30 icing/de-icing cycles without changing the ice adhesional strength. Such effective anti-icing performance was ascribed to the better liquid nature of HD in contact with water and the solid nature of HD under freezing condition, which could decrease the interfacial friction and abrasion of HD against water or ice.

Styrene-Butadiene Rubber by Miniemulsion Polymerization Using In Situ Generated Surfactant.

An alternative approach for the synthesis of styrene butadiene rubber (SBR) copolymer latexes was explored in order to obtain low gel fractions and high solid contents. The ultra-turrax-assisted miniemulsion stabilized by in situ surfactant generation was adopted as the main strategy since this technique can inhibit the eventual presence of secondary nucleation producing polybutadiene particles and also control the cross-linking degree. Styrene monomer was first miniemulsified using an ultra-turrax and in situ generated surfactant using either hexadecane (HD) or octadecyl acrylate (ODA) as the hydrophobe. Dynamic light scattering (DLS) measurements of droplet size indicated faster stabilization and the production of smaller droplet diameters ca. 190 nm (PdI = 0.08) when employing in situ generated potassium oleate (K-Oleate) in comparison to SDS-based miniemulsions. High butadiene-level SBR latexes with ca. 50% solids content, a glass transition temperature (Tg) of −52 °C, and a butadiene to styrene weight ratio of 75:25, were then obtained using the miniemulsion droplets as seeds. Turbiscan and DLS measurements revealed a very stable resulting latex with SBR particle diameter of ca. 220 nm and a low polydispersity index (PdI). Secondary nucleation was prevented as indicated by the low Np/Nd value. Cryo-TEM images showed a narrow distribution of particle size as well as the absence of agglomeration. The gel content was below 10% when tert-dodecyl mercaptan (t-DM) was used as chain transfer agent (CTA).

Self‐Organizing Structures of Phosphatidylcholine in Nonaqueous Solvents: Tailoring Gel‐like Systems

AbstractIn this paper, we investigated the role played by solvent type and additives (water [W] and citric acid [CA]) on the self‐assembly of phosphatidylcholine (PtdCho) into gels. Soybean lecithin (L) served as the PtdCho source used in this study. Lecithin was combined with different oils: hexadecane (HEX), sunflower oil, and medium‐chain triacylglycerol to explore its ability to form organogels. Among the solvents, only HEX was able to form a translucent self‐sustainable gel with lecithin. It was found that the lower water solubility and viscosity of HEX favored gel formation. Small‐angle X‐ray scattering revealed different structures arisen from lecithin organization depending on the organic medium type. In addition, the gel properties of the L‐HEX binary system were also tailored through inclusion of the “primers” W or CA. Oscillatory rheological behavior of organogels was effectively described by a single relaxation‐time Maxwell model, with good fitting at low and intermediate frequencies and with deviations at higher frequencies, indicating the presence of reverse wormlike micelles. Organogels were thermoreversible and, upon CA addition, a substantial increase in zero‐shear viscosity was observed. Incorporation of W led to a similar microstructure to that obtained only with L, whereas CA promoted a different ordering of PtdCho assemblies. Formation and properties of PtdCho‐based organogels were dictated by using different oil types or by changing the polarity of the medium with the incorporation of primers. A better understanding of phospholipid‐based nonlamellar mesophases in organic solvent offers the prospect of adapting the gel properties to the desired application and functionality.

Modelling hexadecane uptake strategies of a rhizospheric bacterial consortium under different hydrodynamic draft-tube airlift reactor conditions

In this study, an analysis of the hydrodynamic effects on the hexadecane (HXD) uptake strategies of a bacterial consortium in an airlift bioreactor was performed using mathematical modelling. The model was developed by considering the capacity of the consortium to consume HXD either directly, through direct interfacial contact (DC) or through uptake of emulsified forms (EF). The model was fitted to experimental data (0.822 < R2< 0.996) under three different aeration strategies, which involved constant and variable superficial gas velocities. For the rhizospheric bacterial consortium used, DC was the primary HXD uptake strategy, which increased in magnitude as superficial gas velocity (Ug) increased (90.8–97.66%). Our findings revealed that both the DC strategy and microbial growth are sensitive to cell hydrophobicity, HXD droplet diameter and the morphological composition of the consortium, which was reflected by the increase in bacterial density on the surface of the HXD droplets, decreased in HXD droplet size and high oxygen uptake values predicted by the model. Furthermore, the model was implemented to simulate the effects of bacterial hydrophobicity and the morphological composition of the consortium on HXD uptake, which showed that DC increased as bacterial hydrophobicity associated with the bacillar shape of bacteria increased.

Pyrene and nile red fluorescence probes for in‐situ study of polarity and viscosity of soil organic coatings implicated in soil water repellency

AbstractSoil water repellency, that is, the reduced ability of soils to absorb water, is thought to be caused by organic coatings with predominantly non‐polar properties on soil particle surfaces. Given the important role of particle surface polarity in determining soil water repellency, we explored the use of fluorescent probes as a method for the direct in‐situ determination of the distribution and polarity of organics on bulk soil surfaces, and of their molecular mobility. We used nile red and pyrene, which have both been used successfully as environmental probes in previous studies, but have not been applied before to bulk soils. The probes were either (a) co‐deposited with other organics known to induce water‐repellent behaviour with acid‐washed sand to produce ‘model soils’ or (b) adsorbed directly onto sandy soils that were naturally water repellent to different degrees, and studied using fluorescence microscopy and steady‐state and time‐resolved fluorescence. Reliable measurements could be made using pyrene as an in‐situ probe on both model and natural soils, and a viscosity/mobility probe on model soils, whereas nile red was found not to be a useful probe. On model soils, made using hexadecane (HEX), octadecane (OCT) or stearic acid (SA) on acid‐washed sand, pyrene excimer formation kinetics showed a decrease in environment mobility as the organic layer changes from a liquid through to a hard wax. Spectra from pyrene adsorbed to natural soils indicated varying environmental polarity and heterogeneity within the soil samples studied.Highlights Exploration of in‐situ fluorescent probes to study polarity and viscosity of organics on soils. Fluorescent probes have never been used in situ on bulk soils before. Pyrene probe shows variation in mobility, polarity and heterogeneity of organics on soils. Pyrene is a useful in‐situ fluorescent probe of polarity and mobility of organics on soils.

Vapor-liquid equilibria and mixture densities for 2,2,4,4,6,8,8-heptamethylnonane + N2 and n-hexadecane + N2 binary mixtures up to 535 K and 135 MPa

In this work, we report high-pressure, high-temperature (HPHT) mixture density and T-p isopleth (bubble (BP) and dew (DP) point) data for hexadecane (HXD) + N2 and heptamethylnonane (HMN) + N2 mixtures from ~323 to 523 K and pressures to ~100 MPa. Isothermal, mixture density data for both mixtures are measured in the single–phase region from the BP pressure to ~135 MPa and with ~14–90 mol% N2. A HPHT variable-volume, windowed view cell is used for both density and phase behavior measurements using the synthetic method. Mixture densities are correlated with the modified Tait equation and isothermal BP/DP data are correlated with an Antoine-type equation to allow for reliable interpolation of the data sets. Mixture densities and BP/DP pressures are modeled with the PC-SAFT equation coupled with pure component parameters calculated with two different group contribution methods. Although fairly reasonable predictions of liquid mixture densities are obtained when the binary interaction parameter, kij, is set to zero for both HXD + N2 and HMN + N2 mixtures, a value of kij equal to at least 0.119 is needed for both systems to obtain reasonable predictions of isothermal p-x behavior.

Surfactant Activity of Artocarpus Heterophyllu Fruit Extract and Application in Oil Removal of Solid Surface

The commercial importance of natural surfactants is evidenced from the increasing trends in their production and the number of industrial applications due to its potential physicochemical properties. Currently, these compounds are moving several industries in the food, chemical and pharmaceutical sectors in which they demand the development of technologies in the industrial and environmental areas. The objectives of the present study were to evaluate the surfactant properties of the Artocarpus heterophyllus plant extract and its application in oil removal of solid surface. Studies on the surfactant properties analyses performed were the surface tension, emulsification activity using different hydrocarbons and vegetable oils, the haemolytic activity, the surface tension stability in different temperatures, pH and addition of salt, test of dispersion, toxicity test, the critical micelle concentration and the ion charges. To evaluate the capacity of this surfactant on oil removal in engine parts, small-scale tests conducted using steel nuts of different sizes. The results showed that this surfactant of vegetable origin obtained from fruit extract exhibited surfactant properties due to the presence of the haemolytic activity and the reduction of the surface tension of water from 72.00 ± 0.14 mN / m to 26.90 ± 0.20 mN / m, with the critical micelle concentration of 0.050 g / L with the increase values of the emulsification activity ranging from 42 ± 0.12 % and 100 ± 0.05 % on all hydrophobic compounds (corn oil, sunflower oil, soybean oil, petroleum, n-hexadecane, diesel and motor oil). The results also showed a considerable stability of these biosurfactants derived from fruit extract submitted to different temperature (stability of 26.11 ± 0.23), pH (stability of 25.63 ± 0.21) and the salt concentrations (stability of 25.79 ± 0.08). And in the result of oil displacement test demonstrated that the biosurfactant vegetable could remove 1.872 cm2 the motor oil. With the characteristic of low toxicity (germination index with values of 100 at 98 %) of biosurfactant and the efficient oil removal on a solid surface between 82.6 ± 0.5 a 78.4 ± 0.6 %, can be considered new perspectives with potential to be marketed and replace the application of chemical surfactants.

Scalable and rapid preparation of Janus fabric by trans-printing method for efficient oil/water emulsion separation

The old-fashioned yet effective trans-printing method was adopted to prepare Janus fabric in the study. Nonwoven cotton fabric was firstly immersed in tetrahydrofuran solution containing P(DMAEMA-co-TMSPMA), a polymer synthesized by copolymerization between N, N-dimethylaminoethyl methacrylate (DMAEMA) and 3-(trimethoxysilyl)propylmethacrylate (TMSPMA), followed by thermal treatment, thus endowing the fabric with the demulsification property. Next, one side of the above prepared fabric was overlapped and rolled with donor fabric containing PDMS-g-TMOS, a polymer synthesized by thiol/ene click reaction between multi-vinyl poly(dimethylsiloxane) (vinyl-PDMS) and 3-mercaptopropyltrimethoxysilane (MPTMOS). The PDMS-g-TMOS polymer infiltrated into the fabric cured with P(DMAEMA-co-TMSPMA) to a certain depth, followed by thermal treatment. Thus, the resultant fabric had both the superhyrophilic side for oil coalescence and the superhyrophobic side for oil permeation. The Janus fabric structure was confirmed by metalloscope, unidirectional water transport property (UDWT), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). When the prepared fabric was used to separate model oil hexadecane (HD) from oil-in-water emulsion, the maximum separation speed was 134.5 kg h−1 m−2. The recovery rate of HD respectively reached 96.0% after 60 min and 99.9% after 150 min. The Janus fabric prepared by the trans-printing method is particularly suitable for industrial production and of great industrial value.

Biofilm mediated synergistic degradation of hexadecane by a naturally formed community comprising Aspergillus flavus complex and Bacillus cereus group

BackgroundThe hydrophobic nature of hydrocarbons make them less bioavailable to microbes, generally leading to low efficiency in biodegradation. Current bioremediation strategies for hydrocarbon contamination, uses induced mixed microbial cultures. This in-vitro study demonstrates the utilization of naturally occurring communities in suitable habitats for achieving highly efficient, synergistic degradation of hydrocarbons in a simple community structure without additives.MethodsEnrichment media supplemented with 1% (7652.53 mg/L) hexadecane (HXD) as the sole carbon source were inoculated with samples of soil with waste polythene, collected from a municipal landfill in order to isolate microbial communities. Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed on HXD grown co-cultures and individual counterparts after 14 days incubation and percentage degradation was calculated. Microbes were identified using 16S rRNA gene and Internal Transcribed Spacer region sequencing. Biofilm formation was confirmed through scanning electron microscopy, in the most efficient community.ResultsThree mixed communities (C1, C2 and C3) that demonstrated efficient visual disintegration of the HXD layer in the static liquid cultures were isolated. The C1 community showed the highest activity, degrading > 99% HXD within 14 days. C1 comprised of a single fungus and a bacterium and they were identified as a Bacillus sp. MM1 and an Apsergillus sp. MM1. The co-culture and individual counterparts of the C1 community were assayed for HXD degradation by GC-MS. Degradation by the fungal and bacterial monocultures were 52.92 ± 8.81% and 9.62 ± 0.71% respectively, compared to 99.42 ± 0.38% by the co-culture in 14 days. This proved the synergistic behavior of the community. Further, this community demonstrated the formation of a biofilm in oil-water interface in the liquid medium. This was evidenced from scanning electron microscopy (SEM) showing the Bacillus cells attached on to Aspergillus mycelia.ConclusionsThis study demonstrates the utilization of naturally formed fungal-bacterial communities for enhanced biodegradation of hydrocarbons such as hexadecane and reports for the first time, synergistic degradation of hexadecane through biofilm formation, by a community comprising of Bacillus cereus group and Aspergillus flavus complex.