Phenol Removal Efficiency Research Articles

Removal of phenolics from aqueous pyrolysis condensate by activated biochar

AbstractAqueous pyrolysis condensate (APC) is rich in acetic acid and has been utilized as feedstock for anaerobic digestion to produce biogas. However, various phenolic compounds dissolved in the APC act as inhibitors, negatively affecting the anaerobic digestion. In this work, we have investigated the feasibility of employing pyrolytic biochar as an adsorbent for the selective removal of phenolics from APC. Biochars derived from the pyrolysis of soft wood, rice husks, and sewage sludge and their respective activated forms have been tested as potential adsorbents for the removal of pure phenol from water solutions. The experimental results showed that, among the adsorbents studied, activated soft wood (ASW) biochar has the highest adsorption efficiency and capacity for phenol removal from water. The kinetic and isotherm studies showed that the phenol adsorption data with ASW biochar may be well described by pseudo second‐order equation and Freundlich model. Batch experiments were carried out to investigate the effects of pH, adsorbent loading, contact time, and temperature on phenolics adsorption onto ASW from APC. At optimal adsorption conditions (pH of 6.0, contact time of 30 min, adsorbent loading of 9.61 , and temperature of 25°C), an adsorption efficiency of 96.9% ± 1.8% and a capacity of 100.78 ± 2.7 mg · g−1 were achieved. Finally, the adsorption efficiency and capacity of ASW for phenolics removal from APC was successfully compared with those of commercial activated carbon, showing comparable results, which indicated the suitability of ASW as an environmentally friendly adsorbent.

Biodegradation of phenol by a halotolerant versatile yeast Candida tropicalis SDP-1 in wastewater and soil under high salinity conditions

In this study, a novel halotolerant phenol-degrading yeast strain, SDP-1, was isolated from a coastal soil in Jiangsu, China, and identified as Candida tropicalis by morphology and rRNA internal transcribed space region sequence analysis. Strain SDP-1 can efficiently remove phenol at wide ranges of pH (3.0–9.0), temperature (20–40 °C), and NaCl (0–5%, w/v), as well as the tolerance of Mn2+, Zn2+ and Cr3+ in aquatic phase. It also utilized multiple phenol derivatives and aromatic hydrocarbons as sole carbon source and energy for growth. Free cells of SDP-1 were able to degrade the maximum phenol concentration of 1800 mg/L within 56 h under the optimum culture conditions of 10% inoculum volume, pH 8.0, 35 °C and 200 rpm agitation speed. Meanwhile, SDP-1 was immobilized on sodium alginate, and the capability of efficiently phenol degradation of free cells and immobilized SDP-1 were evaluated. Shortened degradation time and long-term utilization and recycling for immobilized SDP-1 was achieved compared to free cells. The 1200 mg/L of phenol under 5% NaCl stress could be completely degraded within 40 h by immobilized cells. In actual industrial coking wastewater, immobilized cells were able to completely remove 383 mg/L phenol within 20 h, and the corresponding chemical oxygen demand (COD) value was decreased by 50.38%. Besides, in phenol-contained salinity soil (3% NaCl), 100% of phenol (500 and 1000 mg/kg) removal efficiency was achieved by immobilized SDP-1 within 12 and 26 days, respectively. Our study suggested that versatile yeast Candida tropicalis SDP-1 could be potentially used for enhanced treatment of phenol-contaminated wastewater and soil under hypersaline or no-salt environmental conditions.

The enhanced catalytic activity and stability of Fe3O4-S@C Fenton-like catalyst for phenol degradation

Carbon-coated Fe3O4-S (Fe3O4-S@C) Fenton-like catalyst on carbon cloth is successfully prepared by electrodeposition and subsequent ethanol solvothermal treatment. Fe3O4-S@C with amorphous Fe3O4 presents a rough network structure. Besides, the ≡Fe2+/≡Fe3+ ratio on Fe3O4-S@C is higher than that on sulfur-doped Fe3O4 (Fe3O4-S). The Fe3O4-S@C has the enhanced catalytic activity and improved cycle stability under circumneutral pH. 95.4% phenol is degraded in 18 min with 0.204 ppm of total leached iron. 95% phenol removal efficiency is still maintained after Fe3O4-S@C is reused four times, whereas the Fe3O4-S presents the sharply reduced catalytic performance after the first degradation test. The formed carbon layer not only accelerates the redox cycle of ≡Fe3+/≡Fe2+ by reducing ≡Fe3+ to ≡Fe2+ during the degradation, but inhibits the total iron dissolution effectively. Furthermore, the S6+ can form micro-acidic environment on the catalyst; thus, the degradation reaction can take place under circumneutral pH, and the Sn2− can accelerate the transformation from ≡Fe3+ to ≡Fe2+ through reduction effect. Also, the polar groups of the carbon layer can adsorb more phenol to facilitate degradation process.

Utilization of hydrochar derived from waste paper sludge through hydrothermal liquefaction for the remediation of phenol contaminated industrial wastewater

Abstract Hydrothermal liquefaction derived hydrochar produced from industrial paper sludge was used as an adsorbent to remove phenol derivatives from an industrial wastewater stream. Removal efficiency for phenol was determined using synthetic solutions (10–150 ppm) using batch adsorption experiments at a constant solution pH (8), temperature (25 ± 2 °C) and rotary speed (150 rpm). The adsorption of phenol onto hydrochar followed a Freundlich isotherm and could be described with pseudo-second-order kinetic models. Analysis of the adsorption mechanisms showed that particle film mass transport was the rate-determining step in the adsorption process. A COD removal efficiency of 31 ± 1% was achieved for the industrial wastewater stream. All phenol components in the wastewater stream could be removed, but not all organic acids and cyclic ketones. The performance of the paper sludge-based hydrochar compared well with that of activated carbon (44% COD removal). The final phenol concentration in the wastewater stream was below the acceptable phenol concentration for industrial effluents (1 mg/L). The results show that paper sludge can be converted to a valuable marketable commodity that could reduce waste management costs for a paper mill, while also reducing the cost of expensive adsorbents.

Upgrading sequencing batch reactor using attached biofilm

A conventional sequencing batch reactor (SBR) was upgraded using fixed biofilm carriers with a specific surface area around 18m2 m-3 . The upgraded SBR was investigated to remove phenol from high strength wastewater operated under various operational conditions. The operational conditions used were variable volume exchange ratio (VER) up to 75%, hydraulic retention time (HRT) from (10.7-21.3hr), aeration time (from 2 to 8hr), and initial phenol concentration up to 600mgL-1 . It was found that the upgraded SBR increased the removal efficiencies of biological oxygen demand (BOD5 ), chemical oxygen demand (COD), and total suspended solids (TSS) by about 10% using high strength wastewater without phenol compared to SBR. Furthermore, the removal rate of phenol for the upgraded SBR was higher than conventional SBR by about 18% at 600mgL- of initial phenol concentration under the same operational conditions. Compared to the conventional SBR, the upgraded version reduced the aeration step by 25% and achieved higher removal efficiency of phenol. Moreover, it reduced the excess sludge by about 23% and enhanced its properties by lowering the sludge volume index (SVI) by about 33%. PRACTITIONER POINTS: Upgrading conventional SBR by adding biofilm carriers is necessary for wastewater treatment with high strength wastewater. The upgraded SBR has a higher resistance toward phenol compound due to the presence of the attached biofilm. The upgraded SBR enhances sludge settling properties, decreases the amount of excess sludge, and also reduces the start-up period. The number of cycles per day by upgraded SBR was more than the conventional SBR by 15%. The upgraded SBR is an effective system and has good operational stability.

MIL-88B(Fe)-coated photocatalytic membrane reactor with highly stable flux and phenol removal efficiency

• MIL-88B(Fe)@Al 2 O 3 was used for photocatalytic membrane reactors. • High flux and phenol removal efficiency were obtained using the photocatalytic membrane reactors. • The Fe-clusters of MIL-88B(Fe) acted as reactive sites for the photocatalytic reaction. In this study, MIL-88B(Fe) was successfully prepared and coated onto an Al 2 O 3 substrate. Two photocatalytic membrane reactors (PMRs) for phenol degradation were fabricated using the MIL-88B(Fe)-coated substrates. A coated substrate was either placed into a flat-sheet membrane module to give a photocatalytic flat-sheet membrane reactor (PFMR) or integrated with an Al 2 O 3 hollow fiber membrane module to produce a photocatalytic hollow fiber membrane reactor (PHMR). In the PHMR system, the phenol removal efficiency was significantly enhanced, and the permeate flux remained stable at over 4000 L m –2 h −1 bar −1 . The flux of the PFMR was approximately 80–100 L m –2 h −1 bar −1 ; this lower flux was attributed to the coating and full coverage of MIL-88B(Fe) on the Al 2 O 3 surface. These two systems exhibited recyclability, reusability, and stability over at least three cycles of photocatalytic phenol removal. Characterization of the samples after the reaction illustrated that the iron clusters, which act as the reactive sites, remained stable even though the terephthalate organic linkers were partially destroyed during the photocatalytic reaction. The PMRs developed in this study show promise as effective, feasible, and sustainable systems for wastewater treatment.

Anaerobic digestion of hydrothermal liquefaction wastewater from spent coffee grounds

Spent coffee grounds (SCG) are high water content lignocellulosic residues generated in large amounts by the instant coffee production industry. Recent interest in the use of SCG as biomass for biocrude oil production via hydrothermal liquefaction (HTL) pointed to the generation of an aqueous effluent rich in organic matter of high aromaticity, denominated post hydrothermal wastewater (PHWW). The anaerobic digestion of PHWW was investigated as a treatment option and was evaluated for its energy recovery potential through methane production. Sequencing batch reactors were subjected to increasing initial chemical oxygen demand (COD) levels from 1000 mg COD L−1 to 8000 mg COD L−1, to allow for gradual biomass adaptation to the substrate recalcitrance and toxicity. The highest COD removal rate was observed for an initial COD level of 4000 mg COD L−1. Under this condition, the average methane yield was 187 ± 13 mLCH4 g−1 CODadded, with average COD and total phenols removal efficiencies of 60 ± 1% and 48 ± 4%, respectively. A kinetic evaluation revealed that the methane yield decreased sharply for initial phenolic compounds concentrations above 900 mg GAE L−1. Methane production represented a 22.8% increase in the energy recovered from SCG.

Effects of large salinity fluctuations on an anaerobic membrane bioreactor treating phenolic wastewater

High salinity is becoming more common in industrial process water and final effluents, particularly when striving to close water loops. There is limited knowledge on the anaerobic treatment of chemical wastewaters characterized by distinct salinity fluctuations. This study investigates the high and fluctuating salinity effects on the conversion capacity and membrane filtration performance of an anaerobic membrane bioreactor (AnMBR) in treating phenol-containing wastewater. The AnMBR operated for 180 days with sodium concentrations between 8 and 37 gNa+.L−1. At ≤ 26 gNa+.L−1, approximately 99% COD and phenol removal efficiencies were achieved. At 37 gNa+.L−1, phenol and COD removal efficiencies decreased to 86 and 82%, respectively, while the biomass specific methanogenic activity was 0.12 ± 0.05 gCOD-CH4.gVSS−1.d−1. Due to large salinity fluctuations, phenol and COD removal efficiencies reduced to ≤ 45% but recovered to ≥ 88%. Compared to phenol conversion, methanogenesis was more severely affected. Calculations showed a maximum in-situ phenol conversion rate of 25.5 mgPh.gVSS−1.d−1. Concomitantly, biomass integrity was compromised, and the median particle size severely dropped from 65.6 to 4.3 μm, resulting in a transmembrane pressure increase above 400 mbar. Cake layer resistance to filtration contributed to 85% of the total resistance. Nonetheless, all biomass was effectively retained in the AnMBR. A change in salinity ≥ 14 gNa+.L−1 substantially reduced the microbial richness and diversity. The microbial community was dominated by Bacteria belonging to Clostridiales and Archaea of the orders Methanosarcinales and Methanobacteriales. Our findings demonstrate AnMBRs as suitable techniques for treating chemical process water, with possible subsequent reclamation, characterized by high phenols concentrations and largely fluctuating salinity levels.

New composite material based on Kaolinite, cement, TiO2 for efficient removal of phenol by photocatalysis

Photocatalysis is one of the most important process and was used to eliminate various organic pollutants as phenol in water. In this research study, a new composite containing Kaolinite, cement, and wood fibers modified by titanium oxide TiO2 was elaborated in order to be used in addition of building materials, as photocatalyst for the degradation of phenol. Different kinds and amounts of TiO2 (PC500, P90, and C-TiO2) were immobilized by a simple method inside the composite materials based. The matrix of the hybrid materials was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), N2 adsorption-desorption (BET), and scanning electron microscope (SEM). These investigations confirmed the dispersion of titania in the new composite materials. The FTIR result has shown that clay particles were successfully treated before their insertion in the composite, by the appearance of two peaks at 2921-2851 cm-1. The XRD results reveal the identification of crystalline phase of TiO2 as anatase. The photocatalytic activity of the composite materials was investigated towards degradation of phenol in aqueous solution under UV light irradiation (369 nm). It has been found that photocatalytic efficiency was significantly enhanced when TiO2 is added. The highest photocatalytic activity has been shown by 3% P90-comp of 41.65% in comparison with 3% PC500 and 3% C-TiO2 which are 29.88% and 22.64 %, respectively. It was shown that the experimental data of kinetic reaction are well fitted by first-order model.

Effect of the presence of inorganic anions on the degradation of phenol by dielectric barrier discharge plasma combined with RGO-TiO2

In this study, RGO-TiO2 composites was combined with dielectric barrier discharge plasma for phenol degradation, and the effects of initial reaction conditions and some concomitant inorganic anions (Cl−, CO32−, SO42− and NO3−) on the removal efficiency of phenol were investigated. RGO-TiO2 composite materials were prepared by sol-gel method and characterized by XRD, SEM, FTIR and PL firstly. The experimental results showed that when the input voltage was 90 V and the catalyst dosage was 1.5 g/L, the removal efficiency of 1.06 mM phenol reached 94.7 % after 20 min during reaction. The presence of Cl− and SO42− had a significant inhibitory effect on the degradation of phenol at low concentration, while the inhibitory effect of NO3− could be ignored. Surprisingly, after 10 mM CO32− added, the synergetic system completely degraded the phenol solution within 16 min. The radical quenching experiments was carried out, and the variation of O3 and H2O2 during the degradation of phenol were detected. Finally, the intermediate products of phenol degradation were analyzed by HR-LC–MS, and the possible degradation path of phenol was proposed.

Enhanced removal efficiency of NaY zeolite toward phenol from aqueous solution by modification with nickel (Ni-NaY)

The present work was designed to synthesize novel NaY and Ni modified NaY (Ni-NaY) zeolites for efficient removal of phenol from aqueous solution. The Ni-NaY (FAU, Si/Al = 2.56) was prepared by ion-exchange method at 873 K and pH = 5.8. The characterization of NaY and Ni-NaY was done by EDX, FTIR, ATD/TGA, BET, SEM, and XRD. Characterization results revealed that Ni-NaY showed an increased surface area and pore volume compared to NaY. The phenol adsorption reached the equilibrium within 2 h at pH = 4. A comparative study indicated that Ni-NaY exhibited a high adsorption capacity of phenol compared to NaY, with an average removal of 77.20% and 88.79% by NaY and Ni-NaY, respectively. The low coordination number of Ni cations in NaY structure and the ability of this zeolite to stabilize Ni cations in low-valence states were the main reasons for its superior adsorption performance compared with NaY. The experimental adsorption data were applied to different adsorption and kinetic models to understand the adsorption mechanism. Results indicated that the Freundlich model and pseudo-second order fited the adsorption of phenol on NaY and Ni-NaY. The phenol adsorption on NaY and Ni-NaY zeolite was mediated principally via hydrogen bonding between the hydroxyl (OH) group of phenol and silanol groups of the Ni-NaY zeolite surface. Results also showed that after 5 cycles of regeneration, Ni-NaY had a removal efficiency higher than 90%, which demonstrated an excellent reproducibility of modified zeolite as an adsorbent.

Adsorption of phenol over bio-based silica/calcium carbonate (CS-SiO2/CaCO3) nanocomposite synthesized from waste eggshells and rice husks

A bio-based Silica/Calcium Carbonate (CS–SiO2/CaCO3) nanocomposite was synthesized in this study using waste eggshells (ES) and rice husks (RH). The adsorbents (ESCaCO3, RHSiO2and, CS-SiO2/CaCO3) characterized using XRD show crystallinity associated with the calcite and quartz phase. The FTIR of ESCaCO3shows the CO−23group of CaCO3,while the spectra of RHSiO2 majorly show the siloxane bonds (Si–O–Si) in addition to the asymmetric and symmetric bending mode of SiO2. The spectra for Chitosan (CS) show peaks corresponding to the C=O vibration mode of amides, C–N stretching, and C–O stretching. The CS–SiO2/CaCO3nanocomposite shows the spectra pattern associated with ESCaCO3and RHSiO2.The FESEM micrograph shows a near monodispersed and spherical CS–SiO2/CaCO3nanocomposite morphology, with an average size distribution of 32.15 ± 6.20 nm. The corresponding EDX showed the representative peaks for Ca, C, Si, and O. The highest removal efficiency of phenol over the adsorbents was observed over CS–SiO2/CaCO3nanocomposite compared to other adsorbents. Adsorbing 84–89% of phenol in 60–90 min at a pH of 5.4, and a dose of 0.15 g in 20 ml of 25 mg/L phenol concentration. The result of the kinetic model shows the adsorption processes to be best described by pseudo-second-order. The highest correlation coefficient (R2) of 0.99 was observed in CS-SiO2/CaCO3nanocomposite, followed by RHSiO2and ESCaCO3. The result shows the equilibrium data for all the adsorbents fitting well to the Langmuir isotherm model, and follow the trend CS-SiO2/CaCO3> ESCaCO3> RHSiO2. The Langmuir equation and Freundlich model in this study show a higher correlation coefficient (R2= 0.9912 and 0.9905) for phenol adsorption onto the CS–SiO2/CaCO3nanocomposite with a maximum adsorption capacity (qm) of 14.06 mg/g compared to RHSiO2(10.64 mg/g) and ESCaCO3(10.33 mg/g). The results suggest good monolayer coverage on the adsorbent’s surface (Langmuir) and heterogeneous surfaces with available binding sites (Freundlich).

Improvement in phenol adsorption capacity on eco-friendly biosorbent derived from waste Palm-oil shells using optimized parametric modelling of isotherms and kinetics by differential evolution

Phenolic pollution is very common, and toxic and water-soluble compounds and their derivatives can have significant harmful effects on humans, aquatic life, and the environment. The adsorption method is the most efficient way of handling, but the high cost of biosorbents obstructs the feasibility of this approach. In this study, biomass waste derived from Palm-oil shells is synthesized as an eco-friendly biosorbent for phenol adsorption. A novel inverse modelling method based on differential evolution optimization (DEO) is used to estimate the isotherm and kinetic model parameters, which facilitates to identify the inherent mechanisms in the adsorption process for removing phenol from wastewater. The DEO based model parameters provides an accurate prediction that is very close to experimental data, thus resulting in higher regression coefficient, R2, and relatively low Pearson’s Chi-square, χ2& root mean square error (RMSE). Phenol adsorption found to be following Langmuir isotherm (R2 = 0.995; χ2 = 0.429; RMSE = 4.420) and Pseudo 2nd order kinetic model (R2 = 0.992; χ2 = 0.346; RMSE = 15.58). With a biosorbent size of 0.85 mm resulted in phenol removal efficiency of 98 %. For large scale industrial process, a design methodology is developed to estimate the amount of biosorbent (Palm-oil shell-based GAC) required to meet the desired phenol removal concentration.

Effect of contacting pattern and various surfactants on phenol extraction efficiency using emulsion liquid membrane

Abstract Emulsions prepared using different surfactants, including Span-80, BKC and CTAB, are studied for their stability and phenol remsoval efficiency. The effect of contacting pattern on ELM extraction efficiency is compared in Beaker – Stirrer apparatus and Bubble Flow Recirculation column. The emulsion prepared using Span-80 is relatively more stable than emulsions prepared using other surfactants. The emulsion stability during the extraction process is relatively higher in the Bubble Flow Recirculation column (15 min) than in the Beaker – Stirrer apparatus (10 min). At optimized conditions, the phenol removal efficiency of the emulsion prepared using Span-80 in Beaker – Stirrer apparatus is 96% and in Bubble Flow Recirculation column is 78%. Kinetic studies reveal that the extraction follows zeroth-order kinetics with an average phenol effective diffusivity of 0.0004 s at an initial phenol concentration ranging from 100–500 PPM.

New insight into the photocatalytic degradation of organic pollutant over BiVO4/SiO2/GO nanocomposite

The nanocomposite of BiVO4-based material has been synthesized by one-step solvent method. The morphological, physical, chemical properties of the nanocomposite have been investigated. The results revealed that the surface area of BiVO4, BiVO4/SiO2 and BiVO4/SiO2/GO was 11.13, 28.47 and 43.93 m2/g, respectively. The structural test by XRD proved that the nanocomposites were monoclinic phase of bismuth vanadate. Adsorption and photocatalytic degradation were two main mechanisms that strongly related to pollutant removal efficiency (i.e., methylene blue and phenol). The BiVO4/SiO2/GO nanocomposite obtained the greatest MB removal efficiency due to its high adsorption ability from high surface area, whereas the photocatalytic degradation was insignificant mechanism. In contrast, the relatively low adsorption ability of BiVO4/SiO2/GO nanocomposite was observed when the pollutant was phenol due to negative charge and high stability of phenoxide ions, then the photocatalytic degradation became the main mechanism for phenol removal. The phenol removal efficiency reached approximately 70% in 6 h with H2O2 assistance. The combination of SiO2 and GO improved the surface property of BiVO4-based photocatalyst, however the excessive combination ratio generated the excellent adsorbent material rather than the photocatalyst. Hence, the optimal combination ratio is essential to archive the greatest nanocomposite for photocatalytic application.

Research on dynamics and mechanism of treatment on phenol simulated wastewater by the ultrasound cooperated electro-assisted micro-electrolysis.

In the research, the ultrasound was introduced to the electric-assisted micro-electrolysis system to improve the treatment efficiency of phenol simulated wastewater. The results showed that the phenol removal efficiency was significantly enhanced by the electric-assisted micro-electrolysis method in the presence of ultrasound, which could reach 88.61% under the initial value of pH 4, an iron dosage of 50g/L, a mass ratio of iron/carbon of 1:1, and the initial phenol concentration of 100mg/L. The degradation kinetics of phenol was in accordance with a second-order kinetic model. The synergistic effect of the ultrasonic and electric-assisted micro-electrolysis method was obvious with a synergistic factor at 98.02%. The degradation mechanism of phenol was that the treatment could effectively destroy the benzene ring structure of phenol in the liquid phase with ring-opening reaction and small molecules substances generated. PRACTITIONER POINTS: The article was the pretreatment of coking wastewater. First, the synergistic effects between ultrasound and electrochemical method through the removal ratio of phenol were found. Second, it was showed that the initial pH and applied intensity of voltage had the effects on removal ratio of phenol by the UEME method. Third, the synergy factor (Syn ) between ultrasonic and electrochemical method was 98.02%. Finally, the mechanism of the UEME degradation of phenol was researched. The technology could effectively improve the biodegradability of coking wastewater and provide conditions for subsequent biochemical treatment. So, we thought this article was suitable for the journal.

Colloidal activated carbon as a highly efficient bifunctional catalyst for phenol degradation

A preparation of colloidal activated carbon (CAC) for phenol remediation from groundwater was introduced. The CAC prepared by a simple pulverization technique was an excellent metal-free catalyst for persulfate (PS) activation due to high contact surface area. The removal efficiency of phenol in the PS/CAC system (~100%) was higher than that in the PS/activated carbon (AC) system (90.1%) and was superior to the conventional PS/Fe2+ system (27.9%) within 30 min. The phenol removal reaction occurred both in bulk solution and at the surface of the CAC, as confirmed by Langmuir–Hinshelwood (L–H) kinetic model fitting, FT−IR, and electron spin resonance (ESR) analyses. The downsizing of particle size from AC to CAC played a critical role in the radical oxidation mechanism by leading to the formation of predominant superoxide radical (O2•–) species in the PS/CAC system. Anions NO3–, SO42−, and Cl– slightly inhibited the phenol removal efficiency, whereas CO32−, HCO3− and PO43− did not. Ferulic acid (C10H10O4) was detected as an organic byproduct of phenol oxidation. The use of CAC as a metal-free bifunctional catalyst has an important implication in the PS activation for phenol degradation in groundwater.

Performance Evaluation of a Combined Electrocoagulation– Electrooxidation Process for the Treatment of Petroleum Refinery Wastewater

The present study investigates the application of a combined electrocoagulation-electrooxidation (EC-EO) process for the treatment of wastewater generated from Al-Dewaniya petroleum refinery plant in Iraq. The EC-EO process was examined in terms of its ability to simultaneously produce coagulant and oxidant agents by using a parallel plate configuration system composed of stainless steel plates as cathode and pair of aluminum and graphite plates as anode at two different current concentrations (1.92A/l and 0.96A/l). The results showed that the best conditions for treatment of Al-Dewaniya petroleum refinery wastewater using the combined approach were current concentration of (0.96A/l), current density of (12mA/cm2), NaCl concentration of (2g/l), pH of (7), and electrolysis time of (60 min). In this case COD removal efficiency (93.75%), phenol removal efficiency (96.20%), TDS removal efficiency (6.88%) were obtained with lower specific energy consumption (29.45 kWh/kg COD) and lower aluminum consumption (0.587 x10−3kg/h). The combined process showed to be better than EC process in term of COD and phenol removal efficiencies as well as aluminium consumption. In addition, it was better than EO in term of energy consumption. The combined process also gave buffering effect regarding to pH hence no need for controlling the pH during the operation.

Removal of phenols and COD from petroleum refinery wastewater using electrocoagulation method

This study investigates the possibility of removing phenols and chemical oxygen demand (COD) from petroleum wastewater (refinery wastewater) using an electrocoagulation (EC) reactor supplied with aluminium electrodes. The influence of current density (CD) (4 to 12 mA/cm2), distance between electrodes (DBE) (20 to 40 mm), and treatment time (T) (up to 120 min) was investigated by carrying out several sets of batch flow experiments. The concentrations of COD and phenols were measured using the Hach-Lang spectrophotometer and standard cuvette tests (LCK 514, LCK 314, or APC 400 for COD, and LCK 346 or LCK 345 for phenols (according to the residual concentration). The results of the present study confirmed the ability of the electrocoagulation method to reduce the concentrations of both phenols and COD in petroleum wastewater within a relatively short treatment time. It has been found that the best removal efficiency of COD and phenols were 80% and 58%, respectively. The best removal efficiency was attended, after 100 min of electrolysing, at CD of 8 mA/cm2 and DBE of 20 mm.

Design of Intelligent Network to Predicate Phenol Removal from Waste Water by Emulsion Liquid Membrane

This research introduced Intelligent Network's proposed design for predicting efficiency in the removal of phenol from wastewater by liquid membrane emulsion. In the inner phase of W / O emulsions, phenol extraction from an aqueous solution was investigated using emulsion liquid membrane prepared with kerosene as a membrane phase, Span 80 as a surfactant, and NaOH as a stripping agent. Experiments were conducted to investigate the effect of three emulsion composition variables, namely: surfactant concentration, membrane phase to-internal (VM / VI) volume ratio, and removal phase concentration in the internal phase, and two process parameters, feed phase agitation speed at organic acid extraction rates, and emulsion-to-feed volume ratio (VE / VF). More than 98% of phenol can be extracted in less than 5 minutes. This article describes compares the performance of different learning algorithms such as GD, RB, GDM, GDX, CG, and LM to predict the efficiency of phenol removal from wastewater through the liquid emulsion membrane. The proposed neural network consisted of (7, 11, 1) neurons in the input , hidden and output layers respectively feed forward ANN with various types of back propagation training algorithms were developed to model the emulsion liquid membrane removal of phenols. The values predicted for the neural network model are found in close agreement with the results of the batch experiment using MATLAB program with a correlation coefficient ( R2) of 0.999 and Mean Squared Error (MSE) of 0.004.