While various bioremediation techniques have been widely used at oil spill sites, the in situ efficiency of such techniques on recovering the benthic communities in intertidal areas has not been quantified. Here, the performance of several bioremediation tools such as emulsifiers, multi-enzyme liquid (MEL), microbes, and rice-straw was evaluated by a 90-days semi-field experiment, particularly targeting recovery of benthic community. Temporal efficiency in the removal of sedimentary total petroleum hydrocarbons (TPH), reduction of residual toxicity, and recovery of bacterial diversity, microalgal growth, and benthic production was comprehensively determined. Concentrations of TPH and amphipod mortality for all treatments rapidly decreased within the first 10 days. In addition, the density of bacteria and microphytobenthos generally increased over time for all treatments, indicating recovery in the benthic community health. However, the recovery of some nitrifying bacteria, such as the class Nitrospinia (which are sensitive to oil components) remained incomplete (13–56%) during 90 days. Combination of microbe treatments showed rapid and effective for recovering the benthic community, but after 90 days, all treatments showed high recovery efficiency. Of consideration, the “no action” treatment showed a similar level of recovery to those of microbe and MEL treatments, indicating that the natural recovery process could prevail in certain situations.

The primary aim of this research was to identify the physicochemical properties of the oil and water-in-oil (W/O) emulsions used during a NOFO Oil-on-Water field trials that reduced the performance of the skimmers recovery efficacy during the trials. Extensive studies were performed at SINTEF laboratories with the residues of oil topped (i.e. evaporative loss of crude oil components by distillation process at large scale) for the field trial and compared it with different residues of oil topped by bench scale laboratory procedures. In order to obtain a sufficient stable W/O emulsion for the field trial, bunker fuel oil (IFO380) and various concentrations of an emulsifier (Paramul®) were also added to the residues of oil topped on large scale and investigated through interfacial tension, contact angle, droplet adhesion and “dip and withdraw” tests. The investigations revealed that the addition of an emulsifier lowered the interfacial tension of oil residues, which consequently reduced the adherence properties of the oil and emulsions to the surface of the skimmer material. Too high concentration of an emulsifier (>0,5%) also had a negative effect on the stability of W/O emulsion.

Effective emulsification plays an important role in the treatment of marine oil spills. The negative effects of chemical surfactants have necessitated a search for alternative dispersant that are sustainable and environmentally-friendly. To identify alternate dispersants, oil-in-seawater emulsions stabilized by hydrocarbon-degrading bacteria were investigated. After individual immobilization and surface-modification, the hydrocarbon-degrading bacteria, Bacillus cereus S-1, was found to produce a stable oil-in-seawater Pickering emulsion, which was similar to particle emulsifiers. The individual immobilization and surface-modification process improved the surface hydrophobicity and wettability of the bacterial cells, which was responsible for their effective adsorption at the oil–water interface. Through effective emulsification, the biodegradation of oil was remarkably facilitated by these treated bacteria, because of the increased interfacial area. By combining the emulsification and biodegradation, the results of this reported work demonstrated a novel approach for developing environmentally-friendly bioremediation technology in the field of oil treatment.

Naphthalene is a ubiquitous pollutant of the marine environment, and naphthalene biodegradation has been receiving constant scientific consideration. For cleanup of aromatic contaminated sites, bioremediation methods are considered as economical and safe approaches for the marine environment. The aims of this research are isolation and characterization of naphthalene-degrading bacteria from some marine samples of the Persian Gulf. Fifty four naphthalene-degrading bacteria were isolated from marine samples (sediment and seawater) that are enriched in ONR7a medium with naphthalene as the only carbon source. Some screening tests such as growth at high concentration of naphthalene, bioemulsifier production and surface hydrophobicity were done to select the best and prevalent strains for naphthalene degradation. Determination of the nucleotide sequence of the gene encoding for 16S rRNA shows that these isolated strains belong to these genera: Shewanella, Salegentibacter, Halomonas, Marinobacter, Oceanicola, Idiomarina and Thalassospira. These strains can degrade half of the percentage of naphthalene in 10days of incubation. This research is the first report on isolation of these genera from the Persian Gulf as naphthalene-degrader.

Diverse marine bacterial species predominantly found in oil-polluted seawater produce diverse surface-active agents. Surface-active agents produced by bacteria are classified into two groups based on their molecular weights, namely biosurfactants and bioemulsifiers. In this study, surface-active agent-producing, oil-degrading marine bacteria were isolated using a modified Bushnell–Haas medium with high-speed diesel as a carbon source from three oil-polluted sites of Mumbai Harbor. Surface-active agent-producing bacterial strains were screened using nine widely used methods. The nineteen bacterial strains showed positive results for more than four surface-active agent screening methods; further, these strains were characterized using biochemical and nucleic acid sequencing methods. Based on the results, the organisms belonged to the genera Acinetobacter, Alcanivorax, Bacillus, Comamonas, Chryseomicrobium, Halomonas, Marinobacter, Nesterenkonia, Pseudomonas, and Serratia. The present study confirmed the prevalence of surface-active agent-producing bacteria in the oil-polluted waters of Mumbai Harbor.

A new kind of surfactant-emulsified vortex-assisted dispersive liquid-liquid microextraction method (SE-VA-DLLME) using benzyldimethyldodecylammonium chloride (BDDAC) as emulsifier and disperser has been developed for the determination of imidacloprid and acetamiprid in bottled grenadine and black currant juice samples prior to high-performance liquid chromatography-diode array detection. For grenadine juice and black currant juice, LODs were 0.78 and 0.45 μg/L and 0.81 and 0.83 μg/L and LOQs were 2.8 and 1.7 μg/L and 3.2 and 2.8 μg/L for imidacloprid and acetamiprid, respectively. The linear ranges were wider than 10–3000 μg/L with a correlation coefficient higher than 0.9913, the extraction recoveries were in the range of 61.6–84.2%, the enrichment factors were in the range of 27.0-43.3, and the recoveries and relative standard deviations of the studied neonicotinoids were in the range of 91.94–99.63% and 2.8–6.7%, respectively. The proposed method is presented as a simple, cheap, precise, accurate, and sensitive alternative for the determination of imidacloprid and acetamiprid in bottled grenadine juice and black currant juice samples.

Separation of oil-water (OW) emulsions is investigated using a photocatalytic demulsification approach. Experiments were conducted using two types of photocatalysts, namely, ZnO and TiO₂. The emulsion samples were prepared with oil to water ratios of 1:3, 1:1, and 3:1 and using nonionic surfactant Tween 20 as an emulsifier. The demulsification efficiency was determined using a direct time varying phase separation measurement, while dynamic light scattering (DLS) and microscope imaging (MI) were used to determine the change in emulsion droplets size. The investigation results showed that all the emulsions were destabilized and separated within 30–90 min with demulsification efficiency that ranged from 38 to 90%. On the other hand, untreated control samples remained stable with no phase separation for more than 24 h. For most of the studied experimental conditions, TiO₂ nanoparticles gave better demulsification results than ZnO. Modeling of the batch demulsification kinetics for both systems agreed satisfactorily with the experimental measurements. This could allow its further extension towards design of continuous processes for potential implementation in treatment of industrial oily wastewaters.

The interfacial activity of dispersants can be enhanced by combining two or more surfactants to formulate the dispersant. This paper examines the effects of Bio-Saponin (BS), a phytogenic surfactant on the interfacial activity of synthetic dioctyl sulfosuccinate sodium salt (DOSS) usually adopted as a suitable surface-active agent in dispersants used in dealing with large-scale oil spills. The o/w emulsion created with the binary DOSS-BS was very stable and recorded the least average droplet size compared with that of DOSS only and BS only. Lower surface and interfacial tension values were also obtained from the DOSS-BS binary formulation. The dispersion effectiveness was also higher compared with that of DOSS and BS. However, they were dependent on the salinity and type of crude oil. These observations were attributed to the moderation of the interaction between the anionic head group of DOSS by the polysaccharide hydrophilic group of BS. The results revealed the potential application of DOSS-BS binary dispersant in oil spill remediation and in other processes that would require an effective emulsifier.

Difficulties encountered in estimating the biodegradation of poorly water-soluble substances are often linked to their limited bioavailability to microorganisms. Many original bioavailability improvement methods (BIMs) have been described, but no global approach was proposed for a standardized comparison of these. The latter would be a valuable tool as part of a wider strategy for evaluating poorly water-soluble substances. The purpose of this study was to define an evaluation strategy following the assessment of different BIMs adapted to poorly water-soluble substances with ready biodegradability tests. The study was performed with two poorly water-soluble chemicals—a solid, anthraquinone, and a liquid, isodecyl neopentanoate—and five BIMs were compared to the direct addition method (reference method), i.e., (i) ultrasonic dispersion, (ii) adsorption onto silica gel, (iii) dispersion using an emulsifier, (iv) dispersion with silicone oil, and (v) dispersion with emulsifier and silicone oil. A two-phase evaluation strategy of solid and liquid chemicals was developed involving the selection of the most relevant BIMs for enhancing the biodegradability of tested substances. A description is given of a BIM classification ratio (R BIM), which enables a comparison to be made between the different test chemical sample preparation methods used in the various tests. Thereby, using this comparison, the BIMs giving rise to the greatest biodegradability were ultrasonic dispersion and dispersion with silicone oil or with silicone oil and emulsifier for the tested solid chemical, adsorption onto silica gel, and ultrasonic dispersion for the liquid one.

With continuous development of pesticide dosage forms, emulsifiable concentrates using large amounts of organic solvents are gradually obsoleted. Nanoemulsions with high water content have been developed and the preparation processes also evolved, but these processes still exist some problems, such as poor controllability and high energy consumption. Microfluidic is a controllable nanoemulsion preparation system which mainly applied to pharmaceutical synthesis. In this study, the pesticide phoxim nanoemulsion was prepared by microfluidic technology. The optimized formulation of phoxim nanoemulsion was composed of Tween 80 and pesticide emulsifier 500 as surfactant, hexyl acetate as oil, and n-propanol as co-surfactant. Moreover, when the flow rates of water and oil in the microfluidic system were adjusted to 5 μL/min and 20 μL/min, phoxim nanoemulsion was obtained with a cloud point/boiling point of 109 °C, a particle size of 21.5 ± 0.8 nm and a potential value of − 18.7 ± 0.6 mV. Furthermore, the nanoemulsion had a rapid release effect in vitro which could be fitted by the Ritger-Peppas model. The feeding toxicity of the phoxim nanoemulsion was higher than that of commercial formulation while the contact killing effect was higher than that of the active ingredient. Therefore, pesticide dosage was reduced and the insecticidal effect was enhanced by using phoxim nanoemulsions. These results also confirm the potential of microfluidics as a green process to produce pesticide nanoemulsions.