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The effects of different parameters including membrane type (regenerated cellulose and polysulphone), transmembrane pressure (TMP), the content of oil in the feed, the flow velocity of the feed and pH on the ultrafiltration of an emulsion of kerosene in water were studied. It was found that the important factors affecting ultrafiltration were, in o...
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... high number of OH groups (Fig. 2) in regenerated cellulose membranes apparently makes these membranes very hydrophilic. Fig. 3 shows the chemical structure of polysulphone. There are no OH groups in polysulphone. Thus it is expected that the water permeation (flux) is lower than in a regenerated cellulose membrane with the same pore size while in Table 1 the water ...
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n-Hexane is an easy-to-use fuel for laboratory investigations of hydrocarbon vapor explosions and has been used widely as a surrogate for commodity fuels such as kerosene. As part of our ongoing studies into flammability hazards in aircraft environments, we have been carrying out experiments at reduced pressure, below 100 kPa, in order to measure i...
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... Previously, ultrafiltration (UF) and microfiltration (MF) flat-sheet (FS) membranes for the treatment of oily wastewater have been studied for many years. For example, Rezvanpour et al. (2009) used a bench-scale cellulose UF membrane setup to treat kerosene-contaminated wastewater. The membrane filtration system was operated at a constant transmembrane pressure (TMP) of 3 bar and was able to achieve a total organic carbon (TOC) removal efficiency of 98%. ...
This study investigates the performance of a pilot-scale submerged hollow fiber (HF) ultrafiltration (UF) polytetrafluoroethylene (PTFE) membrane filtration system for the treatment of two different types of oily seawater (i.e., seawater contaminated with light and heavy crude oil). The effects of membrane flux and aeration flow rate on membrane performance and the removal efficiency of different fractions of hydrocarbon, including polycyclic aromatic hydrocarbons (PAHs) were examined. The results for both heavy and light crude oil contaminated wastewater reveal that total petroleum hydrocarbon (TPH) removal efficiency of more than 91% was achieved. This research paper determined the optimal operational parameters for an HF membrane filtration system to obtain a good TPH removal efficiency. This system can easily be upscaled and placed on a barge to treat oily wastewater generated from marine oil spills, which can significantly improve the oil spill response capacity.
... The efficiency of kerosene removal (RE%) and the quantity of kerosene adsorbed (q t ) were calculated by Equations (5) and (6), respectively [19,36]: ...
... The third kinetic model (that is, intra-particle diffusion based on the theory proposed by Weber and Morris) was used to identify the diffusion mechanism [36]. The initial rate of intra-particle diffusion is expressed by Equation (9) [64]: ...
... The pseudo-second order model has been applied in the sorption of oil and metal ions over MWCNTs [65]. The third kinetic model (that is, intra-particle diffusion based on the theory proposed by Weber and Morris) was used to identify the diffusion mechanism [36]. The initial rate of intra-particle diffusion is expressed by Equation (9) [64]: ...
In this paper, the application of multiwalled carbon nanotubes (MWCNTs) based on metal oxide nanocomposites as adsorbents for the removal of hydrocarbons such as kerosene from water was investigated. Functionalized MWCNTs were obtained by chemical oxidation using concentrated sulfuric and nitric acids. V2O5, CeO2, and V2O5:CeO2 nanocomposites were prepared using the hydrothermal method followed by deposition of these oxides over MWCNTs. Individual and mixed metal oxides, fresh MWCNTs, and metal oxide nanoparticle-doped MWCNTs using different analysis techniques were characterized. XRD, TEM, SEM, EDX, AFM, Raman, TG/DTA, and BET techniques were used to determine the structure as well as chemical and morphological properties of the newly prepared adsorbents. Fresh MWCNTs, Ce/MWCNTs, V/MWCNTs, and V:Ce/MWCNTs were applied for the removal of kerosene from a model solution of water. GC analysis indicated that high kerosene removal efficiency (85%) and adsorption capacity (4270 mg/g) after 60 min of treatment were obtained over V:Ce/MWCNTs in comparison with fresh MWCNTs, Ce/MWCNTs and V/MWCNTs. The kinetic data were analyzed using the pseudo-first order, pseudo-second order, and intra-particle diffusion rate equations.
... The capacity of using a flotation is in the range of 10À500 m 3 /h. p0125 Membranes [MF (Koltuniewicz, Field, & Arnot, 1995;Hu & Scott, 2007) and UF (Chakrabarty, Ghoshal, & Purkait, 2010;Rezvanpour, Roostaazad, Hesampour, Nyströ m, & Ghotbi, 2009)] can be successfully applied as a secondary treatment to remove emulsified and dissolved oil from oily wastewater. As in all membrane technologies, both MF and UF membranes still suffer from fouling and concentration polarization caused by adsorbing oil or surfactant, which lead to a reduction in permeate flux with time (Dickhout et al., 2017b). ...
Produced water (PW) generated from oil and gas operations is considered the largest industrial wastewater stream in the world. It generally contains a range of contaminants including high total dissolved solids, high total suspended solids, polar and nonpolar organic compounds, and low surface tension dissolved species. Membrane-based technologies could provide new cost-effective methods to treat PW. However, membrane-based technologies suffer from membrane fouling, which affects their long-term performance. Hence, combined and integrated membrane processes will be required to treat PW efficiently. Using a hybrid membrane process, which may result from combining a conventional process with a membrane separation, could address the issues of fouling (and wetting), and maximize water recovery. In this review chapter, several hybrid membrane processes, are reviewed. Emerging technologies will also be discussed. The effects of important parameters that determine performance of these hybrid systems are discussed.
... Reprinted with permission from Ref. [117]. [31,95,106,158,161,173,174]. In this regard, various experimental design tools like the Taguchi method [31,173,174], response surface method (RSM) [106,158,161] adaptive neuro-fuzzy inference system (ANFIS) [95], etc. are very helpful to obtain a combined effect of the UF variables and the objective functions (Table 11). ...
... [31,95,106,158,161,173,174]. In this regard, various experimental design tools like the Taguchi method [31,173,174], response surface method (RSM) [106,158,161] adaptive neuro-fuzzy inference system (ANFIS) [95], etc. are very helpful to obtain a combined effect of the UF variables and the objective functions (Table 11). Rezvanpour et al. [173] used the Taguchi method in the optimization of membrane material (i.e., PSF, CA) and operating parameters (i.e., TMP, pH, CFV and feed oil concentration) for the treatment of kerosene-water emulsion. ...
... In this regard, various experimental design tools like the Taguchi method [31,173,174], response surface method (RSM) [106,158,161] adaptive neuro-fuzzy inference system (ANFIS) [95], etc. are very helpful to obtain a combined effect of the UF variables and the objective functions (Table 11). Rezvanpour et al. [173] used the Taguchi method in the optimization of membrane material (i.e., PSF, CA) and operating parameters (i.e., TMP, pH, CFV and feed oil concentration) for the treatment of kerosene-water emulsion. ...
The industries like petroleum refining, petrochemicals, metallurgical, oil & gas, etc., generate a substantial volume of oily wastewater, and it is recognized as a potential threat to the environment. The topic of oily wastewater treatment is very topical and important to major industry developments such as shale oil and gas. Among the techniques employed, the treatment of oily wastewater using polymeric ultrafiltration membrane (UFM) has emerged as a cost-effective technique with ease of operation as well as high separation efficiency over the conventional oily wastewater treatment methods. The major limitation of the UFM technique is mainly due to the fouling of membranes because of the accumulation of tiny oil droplets on the surface and blockage of membrane pores. Therefore, the enhanced wettability (i.e., hydrophilicity) and the antifouling behavior of membranes are the key parameters to improve the performance of UFMs. In this review, we briefly highlight the parametric effects on the performance of UFM performance, which includes the (i) composition of the membrane related to the blend-ratio of several additives (namely, polymeric, inorganic, grafted polymers, etc.) (ii) operating conditions (pH, temperature, salinity, oil concentration, and cross-flow velocity of feed, the viscosity of casting solution and salinity of the coagulation bath, etc.) and (iii) process optimization. The review further provides an insight into the fouling of membranes using oily wastewater. Finally, the present review emphasizes the challenges faced for commercial applications of UFM, economic aspects as well as the range of strategies for the researchers to follow.
... Statistical experimental design incorporating design of experiments (DoE) techniques can be used to investigate the effects of all the possible interactions between the factors at one time, while undertaking the fewest possible experiments. A review of the literature revealed that an increasing number of studies are being conducted using DoE approaches in the membrane technology field to optimize operating conditions [10,[27][28][29][30][31][32]. The DoE approaches for robust design include the Taguchi method that combines mathematical and statistical techniques to arrive at a special design of experiments with an orthogonal array (OA) to study multiple factors with a small number of experiments. ...
... An experimental design based on the Taguchi method was used to design the experiments. The Taguchi method applies fractional experimental designs, called orthogonal arrays (OA), to reduce the number of experiments required to determine the optimum conditions based on the results [29,30,42]. One of the important steps in the Taguchi approach is the appropriate selection of OAs, which depends on the number of control factors and their levels. ...
Optimization of the ultrafiltration (UF) process to remove colloidal substances from a paper mill’s treated effluent was investigated in this study. The effects of four operating parameters in a UF system (transmembrane pressure (TMP), cross-flow velocity (CFV), temperature and molecular weight cut-off (MWCO)) on the average permeate flux (Jv), organic matter chemical oxygen demand (COD) rejection rate and the cumulative flux decline (SFD), was investigated by robust experimental design using the Taguchi method. Analysis of variance (ANOVA) for an L9 orthogonal array were used to determine the significance of the individual factors, that is to say, to determine which factor has more and which less influence over the UF response variables. Analysis of the percentage contribution (P%) indicated that the TMP and MWCO have the greatest contribution to the average permeate flux and SFD. In the case of the COD rejection rate, the results showed that MWCO has the highest contribution followed by CFV. The Taguchi method and the utility concept were employed to optimize the multiple response variables. The optimal conditions were found to be 2.0 bar of transmembrane pressure, 1.041 m/s of the cross-flow velocity, 15 °C of the temperature, and 100 kDa MWCO. The validation experiments under the optimal conditions achieved Jv, COD rejection rate and SFD results of 81.15 L·m−2·h−1, 43.90% and 6.01, respectively. Additionally, SST and turbidity decreased by about 99% and 99.5%, respectively, and reduction in particle size from around 458–1281 nm to 12.71–24.36 nm was achieved. The field-emission scanning electron microscopy images under optimal conditions showed that membrane fouling takes place at the highest rate in the first 30 min of UF. The results demonstrate the validity of the approach of using the Taguchi method and utility concept to obtain the optimal membrane conditions for the wastewater treatment using a reduced number of experiments.
... Generally, permeate flux is higher at higher crossflow velocities [27][28][29][57][58][59][60] as an an increase in shear at the membrane surface mitigates fouling. In the case of individual oil droplets that block membrane pores, a detailed analysis of droplet behavior on a membrane in a crossflow-induced shear field is possible [61][62][63][64]. ...
... MF separations of oil-water emulsions have employed membranes in different configurations including: polymeric flat-sheet [13,29,71,78,[99][100][101][102][103][104][105][106][107][108][109][110][111][112][113][114][115][116][117], polymeric tubular [118][119][120][121], ceramic tubular [77,82,85,99,120,[122][123][124][125][126][127][128][129][130][131][132][133][134][135], ceramic tubular with multiple channels [136][137][138][139], ceramic flat disk [29,[72][73][74]99,140,141], hollow fiber [142][143][144], microporous glass tubular [145,146], membrane with slotted pores [93,[147][148][149][150][151], metal membrane with conical pores [152,153] and a few other specialty membranes such as silica-supported PVDF [154] and flexible TiO 2 /Fe 2 O 3 composite membranes [155]. Similarly, UF membranes used to separate oil-water emulsions included polymeric flat-sheet [58,76,77,80,[104][105][106]108,110,, polymeric tubular [189][190][191][192][193][194], ceramic tubular [77,[195][196][197][198][199], ceramic tubular with multiple channels [139,[200][201][202][203], ceramic flat disk [46] and hollow fiber [86,121,143,144,196,[204][205][206][207]. ...
Separation of liquid-liquid emulsions is a challenging problem that has gained in importance with the development of unconventional oil resources. Large volumes of water contaminated by emulsified oil need to be treated for safe disposal or efficient reuse. Among technologies capable of removing oil dispersed into smaller size droplets (< 15 µm), membrane processes occupy a unique niche where the required separation performance and throughput can be achieved at a relatively modest cost. As with most membrane-based processes, separation of emulsified oil entails membrane fouling that requires regular maintenance and imposes additional operational costs. Emulsions present unique challenges in that their fouling behavior is affected by droplets’ deformability, coalescence both in the bulk and on the membrane surface, membrane wetting by droplets and films, pore blockage and intrusion by oil. The purpose of this paper is to overview the literature on the separation of oil-water emulsions by pressure-driven membrane processes with an emphasis on how properties of emulsions and membranes affect separation performance. A particular focus is on membrane fouling by oil including physicochemical bases, detection, diagnosis, and visualization. The review spans studies with both industrial oily wastewater and synthetic model emulsions of various types of oil. The discussion of membrane materials is limited to surface modifications that render membranes more fouling-resistant.
... For C1, the peak at 1747 cm −1 indicates the presence of C_O groups, which may due to the stretching vibrations of C_O in the carboxyl or ester groups. The peaks at 1238, 1161 and 1099 cm −1 correspond to the stretching vibrations of C\ \O in ester groups [36]. For C2, the peaks at 3458 cm −1 and 1306 cm −1 correspond to the stretching vibrations of the O\ \H bonds of the N\ \H groups. ...
The flotation performance of lignite is poor even if a high dosage of the collector is used. In this work, the lignite in the Huolinhe Coalfield of Inner Mongolia was used, and its physicochemical properties were determined by proximate analysis, particle size analysis and Fourier transform infrared spectroscopy. The flotation performances of lignite using six collectors were investigated. Moreover, the flotation responses of lignite with combined collector and two emulsified collectors were compared. It was found that the polar groups in the collector structure were helpful to improve the flotation of lignite through reducing the induction time to 15 ms, only 1/12 of that of the traditional collector (190 ms for diesel). The induction time was in the order of diesel> kerosene> emulsified kerosene> emulsified diesel> C1 (one of the nameless collectors), consistent with the flotation performance. C1 and emulsified collectors significantly improved the flotation performance of lignite by promoting the floating of coarse coal (−500 + 250 μm).
... Petroleum refining industries use large amounts of water for diverse processes and thus generate a huge volume of wastewater which needs to be properly treated before it could be discharged. The conventional chemical methods such as adsorption, gravity separation, filtration, coagulation and coalescence that are frequently applied in water treatment plants to treat refinery wastewater are disadvantageous due to high operation costs, low treatment efficiency, corrosion, recontamination problems, etc. [5]. On the other hand, biological treatment methods can overcome these drawbacks. ...
Rapid consumption of fossil fuels has led to the search for alternative energy sources. Bio-fuels as an alternative energy source require cheap and abundantly available substrates to keep the economics of the production process low. The present study was therefore focused on utilizing raw refinery wastewater by the oleaginous bacterium Rhodococcus opacus for converting it into bio-oil via hydrothermal liquefaction of the lipid rich biomass produced during the treatment process. For treating the wastewater, different operating modes using a bioreactor were evaluated including batch, fed-batch, sequential batch, continuous and continuous with cell recycle using low cost tubular ceramic membrane. Among the different strategies, the continuous cell recycle system proved efficient in terms of complete removal of chemical oxygen demand (COD) (99%) and high lipid production (86%, w/w) at a hydraulic retention time (HRT) of 16 h (dilution rate of 0.06 h ⁻¹ ). Furthermore, the residual bacterial biomass from the bioreactor was treated by HTL to produce bio-oil which showed excellent bio-fuel properties. This study demonstrated the application of R. opacus for simultaneous wastewater treatment and production of bio-oil for energy application.
... Effect of TMP on permeate flux (given by Eq. (6)) is explained as follows: initially, with increasing the pressure, the transmembrane flux also increases until a maximum flux is reached, due to an increase in the driving force across the membrane; further increase of pressure then causes the flux to decrease until the flux becomes independent of pressure. The collapse of flux with increasing pressure is because of the enhanced resistance of the thickening gel layer (as a result of concentration polarization) formed by further accumulation of solute on the membrane surface and also the penetration of larger number of droplets into the membrane pores evincing pore plugging at a faster rate; however, once the solute's convective mass transfer to the membrane surface is balanced by its diffusive flow back to the bulk solution, the permeate flux has attained steady state condition at which it is unfettered by pressure and is solely controlled by the rate of backward diffusive transport from its surface to the solution [192,205,[207][208][209] ...
... Superior flux stability may be achieved by modification of membrane operating conditions, such as cross-flow velocity, TMP, and feed temperature [198,210]. Larger permeate flux has been observed for membranes with higher surface porosity (more number of pores), larger pore size, lower feed oil concentration, greater hydrophilicity, intermittent operation, higher temperature, and/or enhanced cross-flow rate (CFR) [190,194,198,208,209]. Nevertheless, increasing CFR at constant TMP diminishes the percentage of oil rejection because the oil droplets are fragmented at higher CFR, ending in oil diffusion into the pores together with permeate. ...
... Surface coating of membrane applied to tune its hydrophilicity and change of the operation mode (e.g., from parallel-flow to crossflow ) are the means reported to minimize/eliminate the fouling effect [210,212]. However, high hydrophilicity of a membrane for breakup of an O/W emulsion, for instance, may not always guarantee its lack of fouling by oil droplets [208]. ...
... Current methods for treatment of API separator effluent of Tehran refinery do not meet the minimum standards to be reused at boilers and cooling towers or to be discharged to the environment. In this research, to achieve high rejection and permeate flux, effects of four operating parameters, i.e., trans-membrane pressure, backwash time, temperature, and cross flow velocity (or flow rate) in a pilot setup were studied using statistic method or called Taguchi experimental design method that available in literatures151617181920212223. ...
... This software calculated the S/N ratios. Finally, the optimal operating conditions were chosen based on these ratios as illustrated in previous studies [23, 25]. Temperature (T), trans-membrane pressure (TMP), cross flow velocity (CFV), and backwash time (BWT) (at three levels) for MF and UF (PVC) membranes; three factors for UF (PAN) and RO membranes which are T, TMP, and flow rate (Q) (at three levels) are studied in our 12 investigation on the fluxes and rejection of membranes. ...
This paper is accepted by Journal of Water Chemistry & Technology and it will be published at the end of 2017. Manouchehr Nadjafi is first author and Professor Al Arni from King Saud University is third and Corresponding author.
