Phenol removal by enhanced electrocoagulation process with persulfate salt

Introduction. Phenol is classified as priority pollutant. Phenol and its derivatives are stable in water, environmental contamination, and health concerns that are used as raw material in many chemical industries. This study investigated the removal of phenol by the reactivity of free sulfate radicals (SO4•–), activated by electrochemically generated Fe2+/Fe3+ ions which furthermore are evaluated to destroy phenol in aqueous solution. Materials and methods. In the present experimental study, electrocoagulation reactor by iron electrodes is used in the pre­sence of persulfate ions to phenol removing from aqueous solutions. In this regard, the effect of four independent variables including pH, electric current, persulfate dosage, and initial phenol concentration were studied on phenol removal. Results. The study determined the optimum conditions for maximum phenol removal using electro-persulfate process (EPS) as pH 3, 7.4 mM persulfate dosage, 27.78 mA/cm2 current density, and 100 mg/L initial phenol concentration at 30-min reaction time. The results showed that the efficiency of phenol removal was directly related to the initial persulfate dosage. In addition, the pH values, less than the phenol pKa, has slight effect onto the phenol removal. However, it was inversely correlated with a highly alkaline pH and higher phenol concentration. Conclusions. The study concluded that electro-persulfate process is an effective and robust process that can be used for handling of phenol containing wastewater.

Effect of Nickel as Stress Factor on Phenol Biodegradation by Stenotrophomonas maltophilia KB2

This study focuses on the phenol biodegradation kinetics by Stenotrophomonas maltophilia KB2 in a nickel-contaminated medium. Initial tests proved that a nickel concentration of 33.3 mg·L−1 caused a cessation of bacterial growth. The experiments were conducted in a batch bioreactor in several series: without nickel, at constant nickel concentration and at varying metal concentrations (1.67–13.33 g·m−3). For a constant Ni2+ concentration (1.67 or 3.33 g·m−3), a comparable bacterial growth rate was obtained regardless of the initial phenol concentration (50–300 g·m−3). The dependence µ = f (S0) at constant Ni2+ concentration was very well described by the Monod equations. The created varying nickel concentrations experimental database was used to estimate the parameters of selected mathematical models, and the analysis included different methods of determining metal inhibition constant KIM. Each model showed a very good fit with the experimental data (R2 values were higher than 0.9). The best agreement (R2 = 0.995) was achieved using a modified Andrews equation, which considers the metal influence and substrate inhibition. Therefore, kinetic equation parameters were estimated: µmax = 1.584 h−1, KS = 185.367 g·m−3, KIS = 106.137 g·m−3, KIM = 1.249 g·m−3 and n = 1.0706.

Biodegradation of Phenol by Bacillus simplex: Characterization and Kinetics Study

Phenol is one of the main pollutants that have a serious impact on the environment and can even be very critical to human health. The biodegradation of phenol can be considered an increasingly important pollution control process. In this study, the degradation of phenol by Bacillus simplex was investigated for the first time under different growth conditions. Six different initial concentrations of phenol were used as the primary substrate. Culture conditions had an important effect on these cells' ability to biodegrade phenol. The best growth of this organism and its highest biodegradation level of phenol were noticed at pH 7, temperature 28 °C, and periods of 36 and 96 h, respectively. The GC-MS analysis of the bacterial culture sample revealed that further degradation of the catechol by 1,2-dioxygenase produce a cis, cis-mucconic acid via ortho-pathway and/or by 2,3-dioxygenase into 2-hydroxymucconic semialdehyde via meta-pathway. The highest biodegradation rate was perceived at 700 mg/L initial phenol concentration. Approximately 90% of the phenol (700 mg / L) was removed in less than 96 hours of incubation time. It was found that the Haldane model best fitted the relationship between the specific growth rate and the initial phenol concentration, whereas the phenol biodegradation profiles with time could be adequately described by the modified Gompertz model. The obtained parameters from the Haldane equation are: 1.05 h−1, 9.14 ppm, and 329 ppm for Haldane's maximum specific growth rate, the half-saturation coefficient, and the Haldane’s growth kinetics inhibition coefficient, respectively. The Haldane equation fitted the experimental data by minimizing the sum of squared error (SSR) to 1.36 X 10-3.

Packed Bed Column Adsorption of Phenol Onto Corn Cob Activated Carbon: Linear and Nonlinear Kinetics Modeling

In the present study, linear and nonlinear regression analysis for packed bed column adsorption of phenol onto corn cob activated carbon was investigated. The activation of the corn cob provided the activated carbon with enhanced surface area and micropore volume of 903.7m2/g and 0.389 cm3/g respectively. The analysis of the physical properties of the corn cob activated carbon (CCAC) revealed that it contained 33.47% of fixed carbon. SEM images indicated the presence of interspatial pores within the matrix of the adsorbent, while the FTIR analysis revealed that the major functional groups in CCAC were alkanol, alkanes, alkyls, carboxylic acids, ethers, esters, and nitro compounds. The effect of the process parameters influencing the dynamic adsorption process was investigated at flow rates (9 – 18mg/min), initial phenol concentration (100-300mg/l), bed height (5 – 10cm), and particle size (300-800µm). Breakthrough time and adsorption capacity increased with an increase in bed height but decreased with an increase in flow rate, initial phenol concentration, and particle size. At 9mg/min flow rate, 100mg/l initial phenol concentration, 10 cm bed height, and 300µm, the breakthrough and saturation points adsorption capacities were 2.143 and 8.570 mg/g respectively, the volume of effluent treated at saturation point was 12.96L, the length of mass transfer zone (MTZ) was 7.50cm, while 66.13% phenol removal efficiency was achieved. The linear and nonlinear regression analysis of the dynamic column adsorption models viz. Thomas, Adam Bohart, and Wolborska fitted better with the experimental data as compared to Yoon–Nelson. Generally, the nonlinear regression analysis proved to be a better tool for dynamic adsorption model analysis because the model parameters it predicted are in higher proximity to the experimental data when compared to those obtained via linear regression analysis. Conclusively, this study has shown that CCAC can successfully be used for the removal of phenol from aqueous solutions. It also provided experimental evidence that for a more accurate analysis of dynamic adsorption models nonlinear regression tool should be considered.

STUDI PERTUMBUHAN DAN DEGRADASI FENOL OLEH KULTUR TUNGGAL AKTINOMISETES DARI TANAH GAMBUT

AbstrakFenol adalah senyawa organik yang bersifat toksik dan larut dalam air, sehingga mudah menimbulkan pencemaran pada perairan dan menurunkan kualitas air. Penelitian ini bertujuan untuk melihat potensi tiga isolat aktinomisetes asal tanah gambut Riau dalam Minimal Salt Medium yang mengandung fenol pada konsentrasi 0 ppm, 200 ppm, 400 ppm, dan 600 ppm serta mengetahui kemampuan aktinomisetes dalam mendegradasi fenol pada konsentrasi 600 ppm menggunakan metode folin ciocalteau. Potensi pertumbuhan isolat L121, L18, L11 menunjukkan total populasi tidak berbeda nyata dengan penambahan 400 ppm dan 600 ppm fenol, tetapi berbeda nyata terhadap 0 ppm dan 200 ppm fenol. Potensi pertumbuhan tertinggi terdapat pada isolat L121 dan terendah pada isolat L11. Kemampuan degradasi fenol oleh masing-masing isolat adalah L121 sebesar 570,80 ppm (95%), L18 sebesar 218,85 ppm (36%) dan L11 sebesar 97,21 ppm (16%) dari konsentrasi fenol awal 600 ppm pada Minimal Salt Medium. Isolat aktinomisetes ini berpotensi dikembangkan untuk penanggulangan pencemaran di lingkungan.Abstract Phenol is an organic compound is toxic and easily soluble in water so easy to cause pollution in a waters such as water quality degradation. The aim of this research is to see the potential of three isolates of actinomycetes from Riau peat soil in Minimal Salt Medium containing phenol concentration 0 ppm, 200 ppm, 400 ppm and 600 ppm and to know the ability of actinomycetes in degradation of phenol at the concentration of 600 ppm using folin ciocalteu. The growth potential of L121, L18, L11 isolates showed the total population was not significantly different with the addition of 400 ppm and 600 ppm of phenol but significantly different from 0 ppm and 200 ppm of phenol. The highest growth potential was found in L121 isolate and lowest in L11 isolate. The degradation ability of phenols by each isolate was L121 570.80 ppm (95%), L18 218.85 ppm (36%) and L11 was able to degrade phenol 97.21 ppm (16%) from the initial phenol concentration of 600 ppm at Minimum Salt Medium.These actinomycetes have the potential to be developed for the overcome of pollution in the environment.

Biosorption of phenol by modified dead leaves of Posidonia oceanica immobilized in calcium alginate beads: Optimal experimental parameters using central composite design

This study reports the biosorption of phenol using dead leaves of Posidonia oceanica (PO), an endemic seagrass in the Mediterranean Sea. The PO dead leaves were pre-treated with sulfuric acid and carbonized at 500°C for 2 h to increase their adsorptive capacity. Leaves were then immobilized in calcium alginate beads to address problems that arise when free particulate biosorbents are used. Response surface methodology (RSM) based on central composite design (CCD) was carried out to optimize key variables, viz., initial phenol concentration (100–500 mg/L), biosorbent dosage (0.05–0.1 g/50 mL), and alginate beads to solution ratio (1/10–2/10). The effect of the operating variables on phenol biosorption capacity was studied in a batch system and a mathematical model showing the influence of each variable and their interactions was obtained. The predicted second-order quadratic model for the response variable was significant (p < 0.01). Further, an adjusted squared correlation coefficient, R2 (adj) of 97.7% indicated a satisfactory fit of the model. The results of CCD showed maximum biosorption capacity of about 127 mg/g at 500 mg/L initial phenol concentration, 1 g/L biosorbent dosage, and at 1.85/10 composite beads to solution ratio. This work demonstrates the suitability of using PO dead leaves as an effective low-cost biosorbent for the removal of phenol.

Biosorption of phenol by modified dead leaves of Posidonia oceanica immobilized in calcium alginate beads: Optimal experimental parameters using central composite design

This study reports the biosorption of phenol using dead leaves of Posidonia oceanica (PO), an endemic seagrass in the Mediterranean Sea. The PO dead leaves were pre-treated with sulfuric acid and carbonized at 500°C for 2 h to increase their adsorptive capacity. Leaves were then immobilized in calcium alginate beads to address problems that arise when free particulate biosorbents are used. Response surface methodology (RSM) based on central composite design (CCD) was carried out to optimize key variables, viz., initial phenol concentration (100–500 mg/L), biosorbent dosage (0.05–0.1 g/50 mL), and alginate beads to solution ratio (1/10–2/10). The effect of the operating variables on phenol biosorption capacity was studied in a batch system and a mathematical model showing the influence of each variable and their interactions was obtained. The predicted second-order quadratic model for the response variable was significant (p < 0.01). Further, an adjusted squared correlation coefficient, R2 (adj) of 97.7% indicated a satisfactory fit of the model. The results of CCD showed maximum biosorption capacity of about 127 mg/g at 500 mg/L initial phenol concentration, 1 g/L biosorbent dosage, and at 1.85/10 composite beads to solution ratio. This work demonstrates the suitability of using PO dead leaves as an effective low-cost biosorbent for the removal of phenol.

Isolation, Kinetics, and Performance of a Novel Phenol Degrading Strain

Efficient phenol-degrading bacteria is still the key to the biological treatment of phenol-containing wastewater. In this research, a novel phenol-degrading strain N8 was isolated. According to the 16S rDNA identification, it was concluded that the N8 strain was Bacillus sp. IARI-J-20. The wastewater treatment experiments showed that the phenol degrading rate of N8 reached 92.8 % at 24 h with the inoculation amount of 15 %, temperature of 30 °C, pH of 7.2, yeast extract addition of 0.08 %, and initial phenol concentration of 225 mg L–1. Haldane’s model was fit for the growth kinetics of the phenol-degrading strain N8 over a wide range of initial phenol concentrations (50–1200 mg L–1), with kinetic values μmax = 0.33 h−1, Ks = 79.16 mg L–1, and Ki = 122 mg L–1. The yield coefficient reached maximal value when the phenol concentration was 400 mg L–1. When the initial phenol concentration was more than 400 mg L–1, the inhibition effect of phenol became predominant.

Effect of Process Parameters on the Photocatalytic Degradation of Phenol in Oilfield Produced Wastewater using ZnO/Fe2O3 Nanocomposites.

The upstream processing of crude oil is often associated with the presence of phenolic compounds when not properly treated could result in adverse effects on human health. The objective of the study was to investigate the effect of process parameters on the photocatalytic degradation of phenol. The ZnO/Fe2O3 nanocomposite photocatalyst was prepared by sol-gel method and characterized using various instrument techniques. The characterized ZnO/Fe2O3 nanocomposite displayed suitable physicochemical properties for the photocatalytic reaction. The ZnO/Fe2O3 nanocomposite was employed for the phenol degradation in a cylindrical batch reactor under solar radiation. The photocatalytic runs show that calcination temperature of the ZnO/Fe2O3 nanocomposite, catalyst loading, initial phenol concentration and pH of the wastewater significantly influence the photocatalytic degradation of phenol. After 180 min of solar radiation, the highest phenol degradation of 92.7% was obtained using the ZnO/Fe2O3 photocatalyst calcined at 400 ºC. This study has demonstrated that phenol degradation is significantly influenced by parameters such as calcination temperature of the ZnO/Fe2O3 nanocomposite, catalyst loading, initial phenol concentration and pH of the wastewater resulting in highest phenol degradation using the ZnO/Fe2O3 nanocomposite calcined at 400 ºC, initial phenol concentration of 0.5 mg/L, catalyst loading of 3 mg/L and pH of 3. Copyright © 2020 BCREC Group. All rights reserved

Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part I. Evidences of an Autocatalytic Process

The present work is aimed at the understanding of the condensation by-products role in wet peroxide oxidation processes. This study has been carried out in absence of catalyst to isolate the (positive or negative) effect of the condensation by-products on the kinetics of the process, and in presence of oxygen, to enhance the oxidation performance. This process was denoted as oxygen-assisted wet peroxide oxidation (WPO-O2) and was applied to the treatment of phenol. First, the influence of the reaction operating conditions (i.e., temperature, pH0, initial phenol concentration, H2O2 dose and O2 pressure) was evaluated. The initial phenol concentration and, overall, the H2O2 dose, were identified as the most critical variables for the formation of condensation by-products and thus, for the oxidation performance. Afterwards, a flow reactor packed with inert quartz beads was used to facilitate the deposition of such species and thus, to evaluate their impact on the kinetics of the process. It was found that as the quartz beads were covered by condensation by-products along reaction, the disappearance rates of phenol, total organic carbon (TOC) and H2O2 were increased. Consequently, an autocatalytic kinetic model, accounting for the catalytic role of the condensation by products, provides a well description of wet peroxide oxidation performance.