Initial Oil Concentration Research Articles

Optimization Of Biosorption Conditions For Crude Oil Spills Using Acetylated And Unacetylated Biosorbents Derived From Cissus Populnea Leaves Stem And Roots

The biosorption of crude-oil spill using acetylated and unacetylated Cissus populnea leave, stem and root biosorbents was investigated in this study. The acetylated and unacetylated biosorbents was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The FTIR spectra confirmed the formation of the acetyl group while SEM morphological analysis of acetylated biosorbent showed rough macrostructure surfaces with large hollows between the strand. The effectiveness of the biosorbents was evaluated based on their ability to remove crude oil from an aqueous solution. The results sho wed that the acetylated biosorbents had higher oil sorption capacities compared to the unacetylated biosorbents. The highest oil sorption capacity was observed for the acetylated stem biosorbent, which had a sorption capacity of 30.09 g/g. The unacetylated leaves biosorbent had the lowest oil sorption capacity, with a sorption capacity of 20.4 g/g. The leaves and roots biosorbents showed intermediate oil sorption capacities. The study also showed that the biosorption capacity of the biosorbents increased with increasing initial oil concentration and contact time, while decreasing with increasing biosorbent particle size. The results suggest that acetylated Cissus populnea biosorbents have potential as an effective and low-cost alternative for the remediation of crude-oil spills.

Assessment of Dispersed Oil Sorption in Oily Wastewater onto Hydrophobized/Oleophilized Autoclaved Aerated Concrete (AAC) Grains

The discharge of untreated oily wastewater into the environment has serious impacts on human health, living nature, and ecosystems and leads to significant economic losses. Many engineering techniques have been proposed and applied to treat oily wastewater, but limited studies have investigated low-cost and effective techniques using by-products and waste/scrap materials from the construction industry. Materials to treat oily wastewater are needed not only to mitigate environmental pollution but also to promote the reuse and recycling of industrial by-products, especially in developing countries. This study, therefore, examined the sorption capacity of dispersed oil in wastewater (dispersed soybean oil in water; initial oil concentrations, Ci = 10–1000 mg/L; oil droplet size in water <2 μm) onto the hydrophobized/oleophilized autoclaved porous aerated concrete (AAC) grains made from waste scrap in Vietnam by using batch sorption tests in the laboratory. The AAC grains (sizes 0.106–0.25, 0.25–0.85, and 0.85–2.00 mm) were hydrophobized/oleophilized using oleic and stearic acids (coating concentrations of 1.0, 5.0, and 10 g/kg), and two sands (0.18–2.00 and 0.30–2.00 mm) were used as control samples. The results showed that the hydrophobized/oleophilized AAC grains had high sorption capacity for dispersed oil (i.e., high oil removal efficiency) compared to the control sands. Especially, the removal of AAC grains coated with stearic acid was >80% in high oil concentration solutions (Ci = 100 and 1000 mg/L), indicating that the hydrophobized/oleophilized AAC grains have high potential as useful adsorbents to trap dispersed oil in oily wastewater. Moreover, adsorption isotherms were drawn to examine the sorption characteristics of dispersed oil onto AAC grains. For all tested samples, the sorption of dispersed oil increased linearly with increasing equilibrium concentration. The commonly used Langmuir model, on the other hand, did not capture the measured isotherms.

Promising Strains of Hydrocarbon-Oxidizing Pseudomonads with Herbicide Resistance and Plant Growth-Stimulating Properties for Bioremediation of Oil-Contaminated Agricultural Soils

Nowadays, large areas of agricultural land are contaminated with chemical plant-protection products. Agricultural soils are also susceptible to oil pollution as a result of accidents on oil pipelines. Bioremediation of such soils from oil with the help of hydrocarbon-oxidizing bacteria is hindered by the presence of additional pollutants such as herbicides. In this work, seven strains of Pseudomonas were isolated and identified, which showed differences in ability of oil biodegradation (32.7–77.3%). All strains showed resistance to herbicides based on 2,4-D and substances from the class of imidazolinones, possessed phosphate-solubilizing and nitrogen-fixing activity, and produced indolyl-3-acetic acid (305–1627 ng/mL culture liquid). They stimulated the growth of barley and clover in soil with oil, as well as the growth of clover in soil with herbicide. In a vegetative experiment (duration 30 days, initial oil content in soil 2% wt., herbicide based on imazethapyr 0.002% wt.) of barley plants and P. alcaligenes UOM 10 or P. frederiksbergensis UOM 11, oil degradation was 48.1–52.7%, the same strains and clover plants, 37.9–38.6%. The studied bacteria have the potential to be used in the bioremediation of oil-contaminated agricultural soils, including in combination with phytomeliorant plants.

Mann’s Cucumeropsis Seed Shell as an Oil Sorbent: Kinetic, Isotherm, and Thermodynamic Studies

Oil spill cleanup using agricultural wastes, which otherwise cause environmental contamination, has gained popularity. In this study, the feasibility of using Mann's cucumeropsis seed shell, a commonly found agricultural waste, as an oil spill mop, was investigated. To identify the surface characteristics of the seed shell, SEM and BET analyses were employed. Batch crude oil sorption tests were performed under various adsorption conditions to determine the effects of initial oil concentration, contact time, adsorption temperature, and adsorbent dosage. Kinetic study of the sorption process involved the pseudo-first order, pseudo-second order, Elovich, and intraparticle diffusion models. Isotherm analysis involved the Langmuir, Temkin, Freundlich, and Dubinin-Radushkevich isotherms. Additionally, the thermodynamic parameters for the sorption process were established. SEM analysis revealed the porous nature of the seed shell's surface. The BET surface area was 313.2 m²/g. The oil sorption process conformed best to the pseudo-first-order kinetics and Langmuir isotherm. The monolayer sorption capacity of the seed shell was 13.072 g/g. The sorption process was exothermic, with some order at the adsorbent–mixture interface. The study's findings demonstrate that Mann's cucumeropsis seed shell is a potent oil sorbent that is safe for the environment and can be enhanced for use in cleaning up oil spills.

The Electrochemical removal of Oil and COD from petroleum wastewater

Recently, COD and oil concentrations in the water have increased, as a result of reduced water volumes and increased industrial waste being dumped into the river. Increased concentrations of these pollutants lead to health and environmental problems. As the water treatment plants use the usual methods of water treatment and could not reduce the concentration of oil and COD to the limit set by the World Health Organization, so an effective way to treat these pollutants became absolutely necessary. In this study, electrochemical method was used to treat water contaminated with oil and COD, using aluminium and iron electrodes as positive electrode and cathode electrode. A coagulation cell with a volume of 2 litters was also used in the work. Several factors affecting the process of treating oil and carbon dioxide pollutants were studied, and these factors were as follows: Submerge depth, Number of electrodes, the distance between the electrodes. From the results, it was found that the optimum removal was 94.2% for oil, and 99.5% for COD. It was achieved when the number of electrodes was 4 aluminium and 4 irons, the distance between the electrodes was 2 cm, the depth was 12 cm, and the function variables were acidic equal to 7, time 50 min, and voltage 10.5 V. The concentration of sodium chloride is 0.5 g/l and the electrode material is aluminium as anode and cathode and the initial oil concentration is 95 mg per litter, initial COD concentration is 710 mg per litter and the consumption of energy was estimated to be 12 kwh/m³, the TSS was 73 mg/l. The results demonstrated that the electrochemical is a feasible technique for treatment of oily contaminated petroleum refinery wastewater.

Parametrical Function Describing Influences of the Redistribution of Incorporated Oil for Rupture Process Reconstruction in Rubber

The present work is focused on finding (i) the tearing energy at rupture and (ii) the redistribution of incorporated paraffin oil on the ruptured surfaces as functions of (a) the initial oil concentration and (b) the speed of deformation to the total rupture in a uniaxially induced deformation to rupture on an initially homogeneously oil incorporated styrene butadiene rubber (SBR) matrix. The aim is to understand the deforming speed of the rupture by calculating the concentration of the redistributed oil after rupture using infrared (IR) spectroscopy in an advanced continuation of a previously published work. The redistribution of the oil after tensile rupture for samples that have three different initial oil concentrations with a control sample that has no initial oil has been studied at three defined deformation speeds of rupture along with a cryo-ruptured sample. Single-edge notched tensile (SENT) specimens were used in the study. Parametric fittings of data at different deformation speeds were used to relate the concentration of the initial oil against the concentration of the redistributed oil. The novelty of this work is in the use of a simple IR spectroscopic method to reconstruct a fractographic process to rupture in relation to the speed of the deformation to rupture.

An application of advanced oxidation process on industrial crude oily wastewater treatment

Advanced oxidation process, via photo-catalytic oxidation process was demonstrated in this study as one of the promising techniques of simulated oily wastewater treatment. Several effective factors such as initial oil concentration, catalyst dose, stirring speed (rpm), pH value and hydrogen peroxide (H2O2) dose influencing on the photo-catalytic degradation rate of oily wastewater were investigated. The catalyst used in this work was titanium dioxide (TiO2). The solubility of oil in water was increased using emulsifier. Results indicated that the photo-catalytic oxidation process has a good removal percentage of oil from oily wastewater reached to 98.43% at optimum operating parameters of 1 g/L initial oil concentration, 850 rpm, 8 pH, 3 mL H2O2 and 1.5 g/L of TiO2 after 40 min of irradiation time. The degradation reaction follows a first order kinetics with a correlation coefficient (R2) of 93.7%. Ultimately, the application of photo-catalytic oxidation processes at these optimum operating parameters on an industrial oily wastewater collected from an effluent stream of Ras Shukair at Red See supplied by Asuit Petrochemical Company was done in Egypt. The results showed that the best oil removal (99%) was achieved after adding 3 mL of H2O2 in a reaction time of 40 min compared to without adding H2O2.

Removal of cutting oil from wastewater by utilization of novel adsorbent developed from teak leaf (Tectona grandis): equilibrium, kinetic, and thermodynamic studies

The disposal of oily wastewater is a severe environmental problem faced by the metalworking and automobile industries. When released into the environment, oil-contained wastewater severely threatens plant, animal, and human life. Adsorption has emerged as a unique technique, and using natural adsorbents makes it further cheap and more eco-friendly. Removal of both free and emulsified oil from wastewater by using biosorbents was looked upon as an alternative. The present research aims to develop a novel biosorbent from teak (Tectona grandis) leaves suitable for removing oil from wastewater. Batch Sorption studies were carried out by varying pH, sorbent dosage, contact period, mixing speed, and initial oil concentration. The optimum conditions for maximum adsorption efficiency were determined. The results showed that the adsorption of oil onto teak leaf (Tectona grandis) adsorbent follows Freundlich isotherm with a maximum sorption capacity of 10.115 mg/g and a pseudo-second-order kinetic model. The thermodynamic parameter (ΔH = 5033.75 KJ/mol) suggested oil adsorption’s spontaneous and endothermic nature onto the teak leaf (Tectona grandis) adsorbent. The best regeneration efficiency was achieved with 0.01 M HCl.

Generation of condensate bubble aphrons (CBA) by partially vaporized condensate to enhance oil removal from produced water

This paper demonstrates flotation separation for dispersed oil droplets and dissolved organics by preparing condensate bubble aphrons (CBA) by partially vaporizing condensate. The results show that the new CBA consists of a condensate membrane and a gas core, with a three-phase contact angle above 140° from the oil surface due to excellent wettability. At different temperatures and condensate compositions, bubbles are about 25–100 µm in size. The half-life time (140–230 s) of CBA and gas hold-up (10–25%) is much higher than nitrogen bubbles. It shows that the CBA has good stability and dispersibility. The flotation experiment of CBA found that the condensate group distribution ratio was optimally adapted to the temperature, and the optimum oil removal efficiency of up to 87% was obtained when the operating temperature was higher than the bubble point of 25–35 °C. The experimental experiment shown the recommended initial oil concentration (400 mg/L) and the mixing ratio of condensate and water (1.0%). Otherwise, CBA flotation efficiency was 10% higher than dissolved gas flotation. With the addition of flocculant, the CBA flotation efficiency can reach 97% of oil droplets and can achieve 50% removal of Acetic acid (HAc).

A feasibility study for recycling biodegradable adsorbent in the oil spill clean-up from seawater

In the present work, the efficiency of Conocarpus leaves to remove oil from seawater was estimated. Conocarpus leaves were characterized by Brunauer–Emmett–Teller, scanning electron microscopy, Fourier-transform infrared spectroscopy and contact angle. The sorption parameters (sorption time, pH, oil ratio, biomass dose, initial oil concentration and temperature were investigated. The change in the pH of the oil/seawater system does not influence the oil sorption. Maximum oil sorption percent reached 88% at 2 min, 0.35 g at room temperature. The kinetic studies show rapid sorption and the pseudo-second-order kinetic governed the oil sorption. The isotherm modeling displayed that the oil uptake was fitted by the Langmuir isotherm. The outcomes of this work indicated a good sorption capacity (1.76 g/g) of Conocarpus leaves. In addition, Conocarpus leaves can be recycled for 4 cycles until the performance decays under 40%.

Removal of oil hydrocarbons from petroleum produced water by indigenous oil degrading microbial communities

Plugging membrane filters with oil (mostly n-alkanes) constitutes one of the main barriers to treating PW for its integration into industrial and agricultural uses. A previous study shows that the combined supply of protein-rich matter and CO2 stimulates the activity of indigenous oil degrading microbial communities. Here we study the feasibility of using this stimulation method to remove dissolved oil hydrocarbons from petroleum produced water (PW) in storage tanks. The experimental procedure consisted of vial experiments using actual PW collected from the Stillwater and Cushing oilfields of Oklahoma, USA. Experiments aimed to determine the kinetics and degree of oil hydrocarbon degradation, assess the effect of pH and ORP, and elucidate the mechanism of oil degradation by the discovered stimulation method. Our results show that the discovered stimulation method works at mesophilic and thermophilic temperatures, isolated soy protein can be used as a substitute for yeast extract, and HCl can be used as a substitute for Na2S to reduce the ORP of PW to optimum levels for oil hydrocarbon degradation. Our results support the hypothesis that CO2 supplied as NaHCO3 boosts the stimulating effect of protein-rich matter by removing H2, which constitutes a thermodynamic barrier for the degradation of oil hydrocarbons. Initial oil concentrations (0.8–1.9 mg-oil/L) decreased by 40–90 % within 7–35 days. The specific rate coefficient and half-saturation constant to represent the kinetics of oil hydrocarbon degradation are 0.614 day−1 and 5.7 mg-oil/L, respectively.

Geological Structure Features of Carbonate Formations and Their Impact on the Efficiency of Developing Hydrocarbon Deposits

The development of deposits with a complex geological structures is often accompanied by a set of problems associated with optimal decision making. The efficiency of the entire development system depends on the completeness and the quality of the analysis of reservoir parameters. This paper presents methodological approaches for the study of carbonate deposits, and the development of further steps to increase the efficiency of reserve recovery. The secondary transformation of reservoir rocks, resulting in channels of increased conductivity, cracks, and caverns, plays a special role in the nature of the recovery of hydrocarbon reserves from such deposits. Secondary cavernosity leads to violations of the linear laws of fluid filtration in a porous medium, and complicates the field performance prediction based on geological and hydrodynamic modeling. The studied geological structure was detailed using the example of carbonate deposits composed of oil and water- saturated formations, taking into account the results of core studies and the interpretation of geophysical well studies. Furthermore, the parameters of production wells made it possible to confirm that the oil saturated and underlying water saturated formations have hydrodynamic connectivity due to the presence of vertical micro cracks. At the same time, the thickness of the bridge between the reservoirs directly affects the initial water cutting of well production, and further growth dynamics of the water ratio are associated with the structural factors determining the initial oil content of the reservoir. The combination of the obtained dependencies and the distribution model of the reservoir properties along the area made it possible to build a complex map reflecting the predicted development efficiency in certain areas. The integration of the results of various field studies on the injection well stock established that a significant part of the water flows was injected into the water saturated formation, which reduces the efficiency of formation pressure maintenance in the target formation. As a result, in order to reduce the low efficiency injection volume, switching to a more rigid waterflooding system, in terms of the ratio of production and injection wells, is proposed with a further decrease in the injection pressure inside the wells.

Kinetics of Arab Light Crude Oil Degradation by Pseudomonas and Bacillus Strains

The biodegradation of crude oil is a consequence of the presence of a specific enzymatic system in the microorganisms selected: the alkane hydroxylase (AlkH). The enzymatic biodegradation has been described since 1994, when the enzyme was first isolated from P. putida (formerly P. oleovorans), but the kinetics of microbial degradation has been weakly considered. We studied and described in this work the kinetics of Arab Light biodegradation, a light crude oil used for gasoline production (46.4% C7–C12 n-alkanes), using two oleophilic strains (Bacillus licheniformis and Pseudomonas putida). Alkanes were extracted from aqueous solutions in the bioreactors by dichloromethane, with a high ratio aqueous:organic volumes (1:0.2 mL) for the amplification of the GC n-alkane signals, and GC spectra were monitored in time over 40 days. Petroleum emulsions were visualized using optical microscopy as a result of biosurfactant segregation, which is necessary for the enzymatic biodegradation of oil by microorganisms. Kinetic analysis in biodegradation of Arab Light (total petroleum hydrocarbons, TPH) exhibits first-order kinetics with 0.098 d−1 and 0.082 d−1 as kinetic coefficients for 8.6 g/L initial crude oil concentration (30 °C), which results in degradation rates of 843 mg/Ld and 705 mg/Ld in B. licheniformis and P. putida, respectively. These results can be applied for oil spill bioremediation, using these microorganisms with the objective of removing contamination by petroleum alkanes.

Estimation of the storage properties of rapeseeds using an artificial neural network

Rapeseed losses during storage can lead to undesirable difficulties in oil and biodiesel production. In this paper, three artificial neural networks were created to anticipate the main quality parameters of thirteen rapeseed varieties - cultivars and hybrids ( Brassica napus L.) - during drying and storage. The varieties, drying temperature, air velocity and drying time were used as inputs to the artificial neural network model to predict the changes in seed weight and moisture during the drying process. The moisture diffusivity and activation energy of the investigated rapeseed varieties were determined under convective drying. For the experiment, an on-site drying system was used at 40, 60 and 80 °C drying air temperature. The effective diffusivity ranged from: 7.947.10 −10 to 1.459.10 −8 m 2 /s (first drying period) and 4.716.10 −10 to 8.611.10 −9 m 2 /s (second drying period). The predicted Arrhenius constant and activation energy ranged from 17.169 to 42.546 kJ/mol (first drying period) and from 31.261 to 50.474 kJ/mol (second drying period). Seed oil content, free fatty acids and thousand seed weight were determined after drying at different temperatures and after 12 months of storage under the three different storage conditions. To predict these parameters after storage time, a multilayer perceptron model with three layers (input, hidden and output) for three artificial neural networks (ANNs) was used for modelling using the implemented drying parameters (such as: variety, drying temperature, air velocity and drying time, along with initial oil and free fatty acid content and storage type) were used. The prediction of the developed model was accurate enough for the prediction of the output parameters. The coefficients of determination ranged from 0.965 to 0.998 when predicting the weight and moisture of the rapeseed during the drying process and the oil and free fatty acid content and thousand grain weights after the 12 months storage period. • 13 rapeseed hybrids quality parameters were anticipated during drying and storage. • prediction of drying and storage parameters was performed using neural network model. • rapeseed varieties, drying temperature, air velocity and drying time were ANN inputs. • optimization of drying parameters was achieved through multi-object optimization.

Degradation of oily effluents using immobilized photocatalyst: Laboratory experimentation and plant design

In the present work, a simple and flexible solar detoxification system is proposed for the removal of oil contaminants from oily wastewaters. The proposed system can be installed on oil production platforms or on the nearest coastline. Experiments on photocatalytic degradation of oily wastewater were conducted using an immobilized TiO2 catalyst on Pyrex glass tubes (fixed in the focal line of the compound parabolic collector (CPC) using the dip-coating technique). Solar irradiation was the main energy source, while UV irradiation was tested for comparison purposes. The effects of volume flow, initial oil concentration, and addition of hydrogen peroxide on oil degradation were tested. Using an artificial UV lamp and an initial oil concentration of 120 ppm, an oil degradation percentage of 75 % was achieved at a flow rate of 18 ml/s. The results of the effect of initial oil concentration showed oil degradation of 53, 65, 77 and 79 % for initial concentrations of 120, 80, 60 and 40 ppm, respectively. The addition of 0.9 M H2O2 and 1 M H2O2 improved hydrocarbon degradation and resulted in degradation levels of 87 % and 100 %, respectively. The design characteristics of the plant are described based on a capacity of 100 tons of oil spill.

Clay-Alginate Beads Loaded with Ionic Liquids: Potential Adsorbents for the Efficient Extraction of Oil from Produced Water

Produced water (PW) generated from the petroleum industry, during the extraction of oil and gas, has harmful impacts on human health and aquatic life, due to its complex nature. Therefore, it is necessary to treat it before discharging it into the environment in order to avoid serious environmental concerns. In this research, oil adsorption from PW was investigated using clay-alginate beads loaded with ionic liquids (ILs), as the adsorbent material. The effects of several process parameters, such as the initial concentration of oil, contact time, pH, and temperature on the removal efficiency of the beads, were analyzed and optimized. Different characterization methods, such as the Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and thermal gravimetric analysis (TGA), were used to investigate the surface morphology, the chemical bond structure and functional group, and the thermal stability of the ILs-based beads. The results revealed that the clay-alginate-ILs beads indicated a removal efficiency of 71.8% at the optimum conditions (600 ppm initial oil concentration, 70 min contact time, 10 pH, and at room temperature) with an adsorption capacity of 431 mg/g. The FTIR analysis confirmed the successful chemical bond interaction of the oil with the beads. The SEM analysis verified that the beads have a porous and rough surface, which is appropriate for the adsorption of oil onto the bead’s surface. The TGA analysis provides the thermal degradation profile for the clay-alginate-ILs. The beads used in the adsorption process were regenerated and used for up to four cycles.

Hydrophobic Ionic Liquids for Efficient Extraction of Oil from Produced Water

Produced water contaminated with oil has adverse effects on human health and aquatic life. Providing an efficient method for the removal of oil from produced water is a challenging task. In this study, the effects of carbon chain length and the cation nature of ionic liquids (ILs) on the removal efficiency of oil from produced water were investigated. For this purpose, seven ILs containing the bis (trifluoromethylsulfonyl) imide (NTf2) anion, and various cations such as imidazolium, pyridinium, phosphonium, and ammonium, were employed for the removal of oil from produced water via liquid–liquid extraction. The effects of process parameters such as the initial concentration of oil in produced water, contact time, pH, salinity, phase ratio, and temperature on the removal efficiency of oil were studied and optimized. 1-Decyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([C10mim][NTf2]) (IL4) was found to give the highest oil extraction efficiency of 92.8% under optimum conditions. The extraction efficiency was found to increase with increasing cation alkyl chain length from C2 to C10. The extraction efficiency of ILs based on cations follows the order imidazolium > ammonium > phosphonium > anpyridinium. Fourier Transform infrared spectroscopy (FTIR) was used to explore the ILs interaction with oil using [C10mim][NTf2] as a model. In addition, 1H and 13C NMR spectra were recorded to obtain a better understanding of the molecular structure of IL and to investigate the peak shifts in H and C atoms. Moreover, the cell viability of the most efficient IL, [C10mim][NTf2], in human cells was investigated. It has been concluded that this IL exhibited minimal cytotoxic effects at lower concentrations against human cell lines and is effective for the extraction of oil from aqueous media.

Electrospun rough PVDF nanofibrous membranes via introducing fluorinated SiO2 for efficient oil-water emulsions coalescence separation

Oily wastewater pollution is grievous and challenging all over the world and how to effectively and economically remove emulsified oils from wastewater is a tough problem. A novel rough polyvinylidene fluoride (PVDF)-F-SiO2 nanofibrous membrane as the polyester (PET) substrate was fabricated by the facile one-step electrospinning technology with introducing fluorinated SiO2 nanoparticles for effective oil-water coalescence separation. Fluorinated SiO2 could increase the microscopic roughness, leading to a higher hydrophobicity. The obtained PVDF-F-SiO2 nanofibrous membrane had a high under oil contact angle (UOCA) of 122.3° indicating a high under-water hydrophobicity. The prepared membrane could perform the high oil-water emulsion coalescence separation efficiency with 99.2 % for treating surfactant-free hexadecane-in-water emulsions after 5 cycles. The PVDF-F-SiO2 nanofibrous membrane demonstrated high separation efficiencies under different flow rates, initial oil concentrations, and oil types in emulsified oil-water systems. More importantly, the SDBS-surfactant-stabilized hexadecane-in-water emulsion could be separated with efficiencies above 82.0 % after 5 cycles, which showed promising potential in treating oily wastewater.

Statistical Simulation, a Tool for the Process Optimization of Oily Wastewater by Crossflow Ultrafiltration.

This work aims to determine the optimized ultrafiltration conditions for industrial wastewater treatment loaded with oil and heavy metals generated from an electroplating industry for water reuse in the industrial process. A ceramic multitubular membrane was used for the almost total retention of oil and turbidity, and the high removal of heavy metals such as Pb, Zn, and Cu (>95%) was also applied. The interactive effects of the initial oil concentration (19–117 g/L), feed temperature (20–60 °C), and applied transmembrane pressure (2–5 bar) on the chemical oxygen demand removal (RCOD) and permeate flux (Jw) were investigated. A Box–Behnken experimental design (BBD) for response surface methodology (RSM) was used for the statistical analysis, modelling, and optimization of operating conditions. The analysis of variance (ANOVA) results showed that the COD removal and permeate flux were significant since they showed good correlation coefficients of 0.985 and 0.901, respectively. Mathematical modelling revealed that the best conditions were an initial oil concentration of 117 g/L and a feed temperature of 60 °C, under a transmembrane pressure of 3.5 bar. In addition, the effect of the concentration under the optimized conditions was studied. It was found that the maximum volume concentrating factor (VCF) value was equal to five and that the pollutant retention was independent of the VCF. The fouling mechanism was estimated by applying Hermia’s model. The results indicated that the membrane fouling given by the decline in the permeate flux over time could be described by the cake filtration model. Finally, the efficiency of the membrane regeneration was proved by determining the water permeability after the chemical cleaning process.

Microbubble and nanobubble-based gas flotation for oily wastewater treatment: a review

Gas flotation for oily wastewater treatment is based on the attachment of gas bubbles to oil droplets to produce lighter aggregates that rise to the wastewater surface. It is a feasible, promising, and effective method for oily wastewater treatment due to its high separation efficiency with no secondary contamination, cost-effectiveness, and simple operation. This review focuses on separating oil from emulsions by gas flotation using microbubbles (MBs) and nanobubbles (NBs), which offer the advantages of small bubble size, large specific surface area, and slow rising velocity. The properties of different types of gas bubbles and their generation methods were discussed. Different gas flotation system designs and operational parameters were summarized for dissolved gas flotation, induced gas flotation, and electrolytic flotation (EF). The review illustrated that oil removal efficiency in MB- and NB-based gas flotation was affected by various factors including initial oil concentration, pH, temperature, flotation time, and oil droplet size.