Phenol Concentration In Water Research Articles

Effect of Silica Sodalite Loading on SOD/PSF Membranes during Treatment of Phenol-Containing Wastewater.

In this study, silica sodalite (SSOD) was prepared via topotactic conversion and different silica sodalite loadings were infused into the polysulfone (PSF) for application in phenol-containing water treatment. The composite membranes were fabricated through the phase inversion technique. Physicochemical characteristics of the nanoparticles and membranes were checked using a Scanning Electron Microscope (SEM), Brunauer Emmett–Teller (BET), and Fourier Transform Infrared (FTIR) for surface morphology, textural properties, and surface chemistry, respectively. A nanotensile test, Atomic Force Microscopy (AFM), and contact angle measurement were used to check the mechanical properties, surface roughness, and hydrophilicity of the membranes, respectively. SEM results revealed that the pure polysulfone surface is highly porous with large evident pores. However, the pores decreased with increasing SSOD loading. The performance of the fabricated membranes was evaluated using a dead-end filtration device at varying feed pressure during phenol-containing water treatment. The concentration of phenol in water used in this study was 20 mg/L. The pure PSF displayed the maximum phenol rejection of 95 55% at 4 bar, compared to the composite membranes having 61.35% and 64.75% phenol rejection for 5 wt.% SSOD loading and 10 wt.% SSOD loading, respectively. In this study, a novel Psf-infused SSOD membrane was successfully fabricated for the treatment of synthetic phenol-containing water to alleviate the challenges associated with it.

Hydrothermal gasification of phenol with Ru added carbon-metal oxide composite-supported Ni catalysts prepared by sol-gel method

Ru promotion effect on carbon-metal oxide composite-supported Ni catalysts were tested for hydrothermal gasification of phenol in aqueous phase as a model process of wastewater treatment. The catalysts were prepared by the combination of aluminum, titanium and zirconium alkoxide, and polyethylene glycol as an organic template, with the addition of active metals, nickel nitrate hexahydrate and ruthenium chloride. In the hydrothermal gasification at 350 °C, pressure 20 MPa and phenol concentration in water 20 g/L, the effect of the addition of Ru to Ni/C/oxide was observed and the conversion of phenol increased. When the effect of metal oxide was compared at 5 wt% of Ru and 16 wt% of Ni contents, the conversion of phenol increased in the order ZrO2 < Al2O3 < TiO2. The activity of Al2O3 -supported catalysts increased with increasing Ru content while that of TiO2 -supported catalysts did not change with the Ru content.

A Promising Solution for Food Waste: Preparing Activated Carbons for Phenol Removal from Water Streams.

Phenol and its derivatives are highly toxic chemicals and are widely used in various industrial applications. Therefore, the industrial wastewater streams must be treated to lower the concentration of phenol before discharge. At the same time, food waste has been a major environmental problem globally and the scientific community is eagerly seeking effective management solutions. The objective of this study was to understand the potential of utilizing food waste as a renewable and sustainable resource for the production of activated carbons for the removal of phenol from water streams. The food waste was pyrolyzed and physically activated by steam. The pyrolysis and activation conditions were optimized to obtain activated carbons with high surface area. The activated carbon with the highest surface area, 745 m2 g–1, was derived via activation at 950 °C for 1 h. A detailed characterization of the physicochemical and morphological properties of the activated carbons derived from food waste was performed and a comprehensive adsorption study was conducted to investigate the potential of using the activated carbons for phenol removal from water streams. The effects of pH, contact time, and initial concentration of phenol in water were studied and adsorption models were applied to experimental data to interpret the adsorption process. A remarkable phenol adsorption capacity of 568 mg g–1 was achieved. The results indicated that the pseudo-second-order kinetic model was better over the pseudo-second-order kinetic model to describe the kinetics of adsorption. The intraparticle diffusion model showed multiple regions, suggesting that the intraparticle diffusion was not the sole rate-controlling step of adsorption. The Langmuir isotherm model was the best model out of Freundlich, Temkin, and Dubinin–Radushkevich models to describe the phenol adsorption on activated carbons derived from food waste. This study demonstrated that food waste could be utilized to produce activated carbon and it showed promising capacity on phenol removal.

Statistical hydrology for evaluating peatland water table sensitivity to simple environmental variables and climate changes application to the mid-latitude/altitude Frasne peatland (Jura Mountains, France)

Peatlands are habitats for a range of fragile flora and fauna species. Their eco-physicochemical characteristics make them as outstanding global carbon and water storage systems. These ecosystems occupy 3% of the worldwide emerged land surface but represent 30% of the global organic soil carbon and 10% of the global fresh water volumes. In such systems, carbon speciation depends to a large extent on specific redox conditions which are mainly governed by the depth of the water table. Hence, understanding their hydrological variability, that conditions both their ecological and biogeochemical functions, is crucial for their management, especially when anticipating their future evolution under climate change. This study illustrates how long-term monitoring of basic hydro-meteorological parameters combined with statistical modeling can be used as a tool to evaluate i) the horizontal (type of peat), ii) vertical (acrotelm/catotelm continuum) and iii) future hydrological variability. Using cross-correlations between meteorological data (precipitation, potential evapotranspiration) and water table depth (WTD), we primarily highlight the spatial heterogeneity of hydrological reactivity across the Sphagnum-dominated Frasne peatland (French Jura Mountain). Then, a multiple linear regression model allows performing hydrological projections until 2100, according to regionalized IPCC RCP4.5 and 8.5 scenarios. Although WTD remains stable during the first half of 21th century, seasonal trends beyond 2050 show lower WTD in winter and markedly greater WTD in summer. In particular, after 2050, more frequent droughts in summer and autumn should occur, increasing WTD. These projections are completed with risk evaluations for peatland droughts until 2100 that appear to be increasing especially for transition seasons, i.e. May–June and September–October. Comparing these trends with previous evaluations of phenol concentrations in water throughout the vegetative period, considered as a proxy of plant functioning intensity, highlights that these hydrological modifications during transitional seasons could be a great ecological perturbation, especially by affecting Sphagnum metabolism.

Photocatalytic degradation of phenol using silica SBA-16 supported TiO2

Silica SBA-16, an efficient photocatalyst support with cubic (bottle-ink) mesoporous structure, large specific surface area, large pore volume and uniform pore size and titanium oxide (TiO2), a semiconductor compound as the active site were synthesized facilely via one-pot method and photocatalysts denoted as x%TiO2/SBA-16 where x = 2, 5, 10 and 20, in order to examine their photocatalytic ability for phenol degradation in different experimental conditions such as different phenol concentration in water (ppm), various pH of the solution and amount of applied photocatalyst (g/l). In order to confirm the correct structure of the SBA-16 support and prepared photocatalysts, various types of characterization analyses such as N2 adsorption/desorption, X-ray diffraction (XRD), TEM, SEM–EDX, UV–VIS and FT-IR were applied. Based on the employed analyses, it can be claimed that the SBA-16 support and synthesized photocatalysts demonstrated mesoporous structures with cubic pores that are in agreement with reliable literature. After carrying out all of the experimental factors for the phenol degradation process, it was found that the 10%TiO2/SBA-16 photocatalyst in the specific experimental conditions including pH 7, phenol concentration of 100 ppm and 1 g/l photocatalyst dosage achieved the highest performance which was approximately 90% degradation of phenol. Hence these mentioned conditions were chosen as the optimum experimental conditions. COD and TOC tests were employed to study the final products of the process and their results showed that the 10%TiO2/SBA-16 photocatalyst was able to reduce the COD and TOC of phenol solution up to 80% and 85%, respectively, means that the major amount of phenol converted to water and CO2 that are the final products of phenol degradation process.

Direct Optical Research Methods in the Analytics of Phenol

The possibility of determining phenol in water by direct optical methods without the use of wet chemistry and concentration methods is considered. The bounds for determining the concentration of phenol in water from the absorption and luminescence spectra are estimated. As a reason limiting the use of the direct luminescent method for determining phenol, the influence of Raman effect of the solvent is considered, which becomes comparable with the luminescent signal even at phenol concentrations in water at a level of 10 μg/L, despite the fact that the sensitivity of the method is sufficient to determine concentrations that are 50 times less.

PURIFICATION OF WATER FROM PHENOL BY BACTERIA OF THE GENUS PSEUDOMONAS IMMOBILIZED ON NATURAL AND SYNTHETIC CARRIERS

Aim. Optimization of the process of water purification from phenol using bacteria of the genus Pseudomonas (P. cepacia ONU327, P. fluorescens ONU328, P. maltophilia ONU329) immobilized on natural and synthetic carriers. Methods. The concentration of phenol in water was determined by extraction-photometric method using 4-aminoantipyrin. For purification of water from phenol (with a concentration of 200 mg / l) non-pathogenic individual strains of bacteria P. fluorescens ONU328, P. maltophilia ОNU329, P. cepacia ОNU327, immobilized on carriers of different nature (zeolite, mussel doors, river sand, ceramic rings, activated carbon, high peat, synthetic carrier type "VIYA"). Results. There were experimentally confirmed that adhesion of cells of the bacterial strains of P. cepacia ONU327, P. fluorescens ONU328, P. maltophilia ONU329 to zeolite, river sand (which practically do not sorb phenol) contributed to the effective biodegradation of phenol by 96–100% (depending on the selected strain bacteria). The residual concentration of phenol in water during its treatment (for 11 days) by cells of P. fluorescens ONU328 strain or P. maltophilia ONU329 strain immobilized on zeolite decreased from 200 mg / l to 8.0±0.95 mg / l (water purification from phenol (α) – 96%) and up to 2.0±0.14 mg / l (α = 99%) – when using immobilized cells of the strain P. cepacia ONU327. It was established that when river microorganisms-destructors were immobilized on the river sand, the residual concentration of phenol in water on the 11th day of treatment was 6.0 ± 0.55 mg / l (α = 97%) and 2.0±0.14 mg / l (α = 99%) – respectively for the strains of P. maltophilia ONU329 and P. fluorescens ONU328; and reached the level of maximum permissible concentration (MPC = 0.001 mg / l) – in the case of river cells of strain P. cepacia ONU327 immobilized in the sand of the river. It was established experimentally that the acceleration of water purification from phenol occurred when using cells of bacteria of the genus Pseudomonas (P. cepacia ОNU327, P. fluorescens ONU328) immobilized on ceramic tubes and a fibrous nozzle of the “VIYA” type. Within 5 days of exposure, the degree of water purification from phenol immobilized on the fibrous attachment of the VIYA type by destructive microorganisms, taking into account the control correction (native unmodified sorbent of the VIA type) reached 97% – as a result of the action of the strain P. cepacia ONU327; and 99% – as a result of the strain P. fluorescens ONU328. Conclusion. To accelerate the purification of water from phenol (for 5 days) by 97–99%, it is recommended to use the strains of the bacteria P. cepacia ONU327 and P. fluorescens ONU328 immobilized on a fibrous nozzle of the type "VIYA". Full dephenolization of water is observed when it is treated with the strains of bacteria P. cepacia ONU327, P. fluorescens ONU328, which are immobilized separately on activated carbon, river sand (for the strain P. cepacia ONU327) and on the mussel doors (for the strain P. fluorescens ONU328), respectively.

DESTRUCTION OF PHENOL AT THE FORMATION OF POLYVIDOUS BIOFILM ON NATURAL AND SYNTHETIC CARRIERS IN THE BIOFILTER

Aim. To determine the effectiveness of the process of water purification from phenol by microorganisms-destructors in the formation of a polyvidiofilm biofilm on natural and synthetic carriers in a biofilter. Methods. An association of phenol bacterium destructors — Aeromonas ichthiosmia ONU552, Basillus subtilis ONU551, Pseudomonas maltophilia ONU329, Pseudomonas fluorescens ONU328, Pseudomonas cepacia ONU327 was used. Stained biofilms were stained with 1% acridine orange solution. Microscopy of the samples was carried out under a Carl Zeiss fluorescence microscope and a Carl Zeiss, Primo Star light microscope with photo fixation. The concentration of phenol in water was determined by the extraction-photometric method using 4-aminoantipyrin. Results. Using fluorescence microscopy, it was confirmed that bacteria used for purification of water from phenol - destructors formed a biofilm in a biofilter on carriers of different nature – ceramic tubes, mussel valves, peat, zeolite, activated carbon, synthetic media such as "VIYA", sand. In laboratory conditions, the effectiveness of the operation of a column-based biofilter of flow-up-stage type with layer-by-layer complex loading of sorbents during purification of phenol-containing water (initial concentration of phenol – 300 mg/l) was confirmed. After 2 hours of the biofilter operation, the degree of water purification was 40% (residual phenol concentration in water 180±17.2 mg/ l), which was associated with phenol sorption on carriers; during biodegradation, it reached 90% (residual phenol concentration in water – 29.5±2.8 mg/l) on the 6th day. In the following days, the efficiency of the biofilter with continuous intake of phenol-contaminated water was at the level of 50–75%, and in the stationary-cyclic mode reached 80–90% (the concentration of phenol in the water varied from 29.5±2.8 to 60±5.7 mg/l). Conclusion. The new microbial consortium forms a biofilm on natural and synthetic filter carriers, which contributes to the effective purification of water from phenol and the flow-through biofilter operation time (up to 2 months) without additional regeneration.

REMOVAL OF PHENOL FROM WATER BY BACILLUS SUBTILIS ONU551 BACTERIA, ADHESIZED ON THE CARRIERS OF DIFFERENT NATURE

Aim. Investigation of the efficiency of removal phenol from water by bacteria Bacillus subtilis ONU551 adhered on the carriers of different nature. Methods. The concentration of phenol in water was determined by extraction-photometric method using 4-aminoantipyrin. The significance of the differences between the mean values of the residual concentration of phenol in water was determined by Student's criterion at a significance level of at least 95% (p ≤ 0.05). Data processing was performed using the program Microsoft Office Excel 2003. Results. The ability of a B. subtilis ONU551 bacterial strain isolated from waste water produced by pharmaceuticals to oxidize phenol was experimentally established. The concentration of phenol in water during its treatment with free cells of the B. subtilis ONU551 bacterial strain in the amount of 5.5×105 CFU/ml for 5 days of exposure decreased from 200.0 to 112.0±5.5 mg/l (by 44% ), reaching maximum on the 15th day – the degree of phenol removal from water was 99-100%. Adhesion of B. subtilis ONU551 bacteria to the surface of natural (zeolite, peat, activated carbon, sand), synthetic (ceramic tubes, fibrous nozzles of the “VIYA” type) of carriers accelerated the removal of phenol from water 1.4–2.5 times , compared to the treatment of water by free bacterial cells. The residual concentration of phenol in water during its treatment with B. subtilis ONU551 bacteria adhered on sand and on “VIYA” type fiber packing decreased for 6 days from 200.0 mg/l to 9.0±0.25 mg/l and 6.0±0.54 mg/l, respectively (by 95–96%) and on the 11th day was at the level of maximum permissible concentration (0.001 mg/l). The degree of removal of phenol from water by B. subtilis ONU551 bacteria adhered on mussel doors, peat and zeolite at the end of cleaning (11 days) ranged from 87% to 99%; and reached 100% – when used as the carriers of activated carbon, ceramic tubes. Conclusion. The use of B. subtilis ONU551 bacteria adhered on natural and synthetic carriers – mussel shutters, peat, sand and fibrous attachment of “VIYA” type ensures 100% removal of phenol from water.

Optic fiber with Er3+:YAlO3/SiO2/TiO2 coating and polymer membrane for selective detection of phenol in water

We present a high-selectivity photochemical fiber-optic sensor in which a plastic optical fiber (POF), TiO2-based composite, and polymer membrane are coupled for detection of phenol concentrations in water. A thinned POF is coated with TiO2-based composite, which is composed of Er3+:YAlO3/SiO2/TiO2 (EYST) and acts as the sensing region. The EYST coating shows good light-inducing capacity at the core–coating interface and high photocatalytic activity in the visible light region. The polymer membrane is synthesized using PEBA2533 doped with β-cyclodextrin and shows high phenol selectivity and permeability; thus, phenol molecules can freely permeate the membrane and are then transferred, become attached to the surface of TiO2 nanoparticles, and are photocatalytically degraded. Photocatalytic degradation of phenol improves the refractive index (RI) and absorbance of the solution because of the photocatalytic byproducts; consequently, the transmitted output light intensity of the sensor changes, and the phenol concentration is accurately detected by measuring the change in the light intensity. Experimental results indicate that the prepared device detects phenol in water with high selectivity and pH independence; in phenol detection, the novel sensor shows a sensitivity of −0.195 × 10−3 (mg/L)−1 and a low limit of detection of 40 μg/L.

Carbon nanotubes as superior sorbent for removal of phenol from industrial waste water

Organic pollutant substances have direct effect on humans and animals. Wastewater containing organic pollutant like phenol compound can contaminate ground water resource and thus lead to a serious ground water problem. This study present the adsorption technique of (MWCNTs) which is used as adsorbents for the removal of phenol compounds from synthetic contaminated water. Many parameters are studied like pH, agitation speed, contact time and adsorbent concentration to determine their influence on the removal of phenol and on adsorption rate .The concentration of phenol in water before and after treatment was determined (analyzed) using high performance liquid chromatography technique (HPLC).The kinetic studies for adsorption followed the pseudo-second order model. The adsorption isotherm fit with Langmuir isotherm. The optimum conditions using MWCNTs were contact time 120 min, pH 7, agitation speed 130 rpm and dose of adsorbent 0.3 g. The removal percentage was 85.54%.

Plackett-Burman Factorial Design for the Optimization of a Spectrophotometric Flow Injection Method for Phenol Determination in Tap and Bottled Water Using 4-Aminoantipyrine

Plackett-Burman and Quarter fraction 25-2 factorial designs were applied to evaluate a spectrophotometric flow injection method in order to determine phenol in water by using 4-aminoantipyrine (4-aap) as derivatizing reagent. With a minimum number of experiments, the designs enabled the best conditions for phenol analysis: 80 cm and 180 cm reactors; flow-rates being: NH3 1.0 mL min-1; 4-aap 0.35 mL min-1 and K3[Fe(CN)6] 0.35 mL min-1, [NH3] 0.064 mol L-1, [4-aap] 9.84 × 10−3 mol L-1, [K3[Fe(CN)6]] 0.02 mol L-1, and an injection volume of 200 μL. With the optimized method it was possible to increase the lineal range from 0.3 μg mL-1 to 30 μg mL-1 and also to quantify the maximum allowable phenol concentration in water in comparison with other standard and flow injection methods whose lineal range are from 0.5 μg mL-1 to 20 μg mL-1 and from 0.5 μg mL-1 to 16 μg mL-1, respectively. The detection limit was of 0.13 μg mL-1 and the regression coefficient was of 0.9999, making possible a throughput of 36 determinations an hour with a minimum consume of reagent. With the proposed method, a distillation step was not necessary to remove sulfates but, when the sulfate:phenol ratio was higher than 83, the analytical signal for phenol increased 8%, but hypochlorite interfered with the signal when the ypochlorite:phenol ratio was higher than 1.

Real Time Quantification of Phenol in Aqueous Solutions Using a Quartz Crystal Microbalance

Phenol (C6H5OH) is an organic compound which is widely used in the industrial production of plastics, paints, rubber, paper, and soaps; However, due to its characteristics of toxicity and persistence in the environment is registered in the list of hazardous substances of the Environmental Protection Agency (EPA) [1,3]. One of the main effluents in which phenol is found are industrial wastewater by which the permissible limits established by the competent environmental authorities are reached, which causes serious problems in the health of people living in places nearby the points of water dump. There are several techniques and methods for determining phenol concentration in water. Conventional techniques include visible ultraviolet spectrophotometry (UV-VIS), High Performance Liquid Chromatography (HPLC), and Gas Chromatography coupled with Mass Spectrometry (GC-MS). These techniques, although characterized by their precision, require a sample pretreatment, high cost equipment and consumed long analysis times [1,3], which makes it difficult to obtain results in real time that allow the control in the concentration of phenol in water before of being poured. One of the systems that has gained importance for measuring organic compounds in water and in real time is the Quartz Crystal Microbalance (QCM). This technique comprises a thin quartz crystal sandwiched between two metal electrodes and senses the changes in frequency that suffers the quartz crystal when a certain amount of mass is deposited on its surface [1,3]. In order to improve the sensitivity of the QCM, there have been used coatings on quartz crystal electrode surface, for example for phenols determination polymethylmethacrylate (PMMA) is used. The main objective of this research is to determine in real time and in continuous flow the concentration of phenol in water using the technique QCM with PMMA as coating on quartz crystal electrode surface. This work is conducted in two stages mainly:1. Determination of a suitable layer of PMMA to use as coating on quartz crystal electrode surface, and 2. Determination of the concentration of phenol using the coating of PMMA prepared in the stage 1.Results have shown that the PMMA films are more uniform when is used dichloroethane as solvent instead of chloroform, and the stability and sensitivity in the measurements are improved due to its vapor pressure that allows more dispersion of the polymer during spin coating, which is consistent with other authors [2]. The coating of 0.2% w/v of PMMA/dicloroethane allowed the shortest response time with adequate sensitivity. Finally, increase in the concentration of phenol increases the changes in frequency of the quartz crystal in a linear way as shown in Figure 1, which is consistent with other authors [1]. Figure 1. Change of frequency changing concentration of phenol Keywords : Quartz crystal microbalance, PMMA, phenol, water, real time. Mirmosheni, A., Oladegaragoze, A. Application of the quartz crystal microbalance for determination of phenol in solution. 2003. Sensors and Actuators, B: Chemical, Vol.98 (1), p. 28-36.Mohajerani, E. Morphological and thickness analysis for PMMA spin coated films. 2007. Journal of optoelectronics and advanced materials, Vol. 9 (12), p. 3901-3906.Reddy, S. Detection of phenol in aqueous solution using an AT-cut quartz thickness shear mode sensor. 2000. Materials Science and Engineering C, Vol. 12 (1), p. 23-28. Figure 1

Phenol Removal from Contaminated Wastewater Using Activated Carbon/Zeolite Composite Coated with Titanium Dioxide

Phenol and phenolic compounds in wastewater from various industries were toxic to water livings and human even in ppm concentration. A number of photocatalysts and adsorbents were applied for the low cost and good efficiency wastewater management to reduce phenol concentration in water. In this work titanium dioxide, one of high efficiency photocatalysts which is widely used in water treatement, was coated on the fabricated adsorbent composite substrate. The composite substrate composed of activated carbon and NaA zeolite presents high phenol adsorption because of high porosity and good ion exchange properties resulting in good adsorption property. Accordingly, the absorption could promote the photocatalytic activity of TiO2 catalyst. As the specimens were easily disposed after water treatment process, therefore, it was a good choice for lower energy consumption. The composite substrate was easily fabricated by simple extrusion and fired under non oxidation atmosphere at 650°C for 3 hours. Then polyurethane foam was inserted into the composite substrate to make it be able to float and be swirled by wind near water surface to get more UV excitation than deeper water. Phenol concentration was investigated by the UV absorbance at 270 nm using UV-Vis spectrophotometer. The XRD and SEM were used to study phase crystal structure and morphology of the composite.

Development of Simple Bacterial Biosensor for Phenol Detection in Water at Medium Concentration using Glass Microelectrode

Water is one of the most fundamental natural resources in earth. The availability of clean water becomes a global interest. Many human activities result in water pollution. One from many pollution substances in water is phenol. Phenol is a very common residual compound in industrial activity. Extensive use of phenol in industry degrades water quality. Regulation has been set in many countries to prevent further damage to the water resource caused by phenol and limiting phenol concentration in water before released into the environment. Therefor it is importance to develop a sensor which can detect phenol concentration in water to be used as a wastewater quality control system. This paper presents a development of bacterial biosensor using Pseudomonas putida and Pseudomonas fluorescens as a biological sensitive material. The sensor was made from glass micro electrode using Ag/AgCl electrode as reference electrode, silver electrode and cellulose ester. The Pseudomonas putida was entrapped inside the nutrient solution and separated by cellulose ester membrane from water containing phenol. It was found that the Pseudomonas putida in used must be growth in 10 hours to reach its optimum growth condition. Linear relationship between biosensor output voltages to phenol concentration was measured for phenol concentration below 200 ppm. The sensitivity of the developed biosensor was 72mV/ppm for Pseudomonas putida and 68.8 mV/ppm for Pseudomonas fluorescens .

Removal of Phenol from Water Different Types of Carbon – A Comparative Analysis

Toxic organic substances are considered among the pollutants that have direct effect on humans and animals. Industrial wastewaters containing dissolved phenol can contaminate groundwater resources and thus lead to a serious groundwater pollution problem. In the present research, the adsorption technique for the efficient removal of phenol pollutants at trace level in water was employed. Four type of micro and nanocarbon materials including carbon nanotubes (CNTs) and carbon nanofibers (CNFs) as nano carbon adsorbents, activated carbon (AC) and industrial carbon fly ash (CFA) as micro carbon adsorbents were used to remove phenol from water. Characterization of these adsorbents was performed by Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy(TEM), Thermogravimetric Analysis (TGA), BET specific surface area while the concentration of phenol in water before and after treatment was analyzed using UV-Spectroscopy. The pH (3-9) of the solution, was varied in order to determine their effect on the removal of phenol from water and hence on the adsorption rate.

ТЕХНОЛОГІЧНИЙ ПРОЦЕС ОБЕЗФЕНОЛЮВАННЯ ПРОМИСЛОВИХ СТОКІВ

Розглянуто основні напрями глибокої очистки промислових стоків від фенолів. Наведеноїх недоліки. Показано, що перспективним методом очистки води від фенолів може бути їхокиснення на суспензійному MnO2.Basic trends in deep treatment of waste waters for elimination of phenols have been studied.Their limits of application are pointed out. Prospective method of phenol elimination by oxidationon MnO2 suspension has been proposed.Рассмотрены основные направления глубокой очистки промышленных стоков от фено-лов. Приведены их недостатки. Показано, что перспективным методом очистки воды отфенолов может быть их окисление на суспезионном MnO2.

Promotion of plant growth and in situ degradation of phenol by an engineered Pseudomonas fluorescens strain in different contaminated environments

We show that Pseudomonas fluorescens strain P13, a plant growth-promoting bacterium, enhanced the growth of corn in uncontaminated soil but not in contaminated soil, perhaps because of its inability to reduce phytotoxicity. Another bacterial strain, Pseudomonas aeruginosa strain SZH16, showed in situ phenol-degrading activity and contained a plasmid loaded with a gene encoding for catechol 2, 3-dioxygenase, an important enzyme in the degradation pathway of aromatic compounds. We implanted this biodegradation ability into strain P13, using horizontal gene transfer techniques using strain SZH16 as the donor and P13 as the recipient, to generate a phenol-degrading transconjugant which obtained the effective plasmid from strain SZH16. Introduction of the transconjugant P13 strain into an artificially phenol-spiked soil promoted the growth of corn and in situ phenol degradation, and the increase in plant biomass correlated with the decrease in soil phenol content. Furthermore, the transconjugant P13 strain was also found to stimulate corn growth and reduce phenol concentration in water containing phenol and in historically contaminated field soils, indicating that the transconjugant strain could promote plant growth in both contaminated and uncontaminated environments. The transconjugant P13 strain was more efficient than either strain P13 or SZH16, and shows how plant growth-promoting bacteria which show no, or only limited, ability to degrade organic pollutants may be modified. This technique is attractive for many environmental remediation and agronomic applications.

The role of mixing in high performance Adsorptive Micellar Flocculation

Two alternative mechanisms allow the capture of pollutants by Adsorptive Micellar Flocculation: adsorption of organic molecules as Al 3+-complexes onto the surface of micelles (e.g. benzoic acid), and solubilisation of organic molecules into the micelles, facilitated by higher hydrophobicity of the micellar phase and enhanced transfer through the palisade by complexation with Al 3+ (e.g. phenol). The impact of each of the mechanism is dependent on the mixing conditions, and the balance between them can be used to optimize the separation of different types of pollutants. The data obtained indicate that a seven-step AMF process operating within the same time scale (about 2 h) than a MEUF separation would reduce the concentration of phenol in water from 0.128 M (12,000 ppm) to about 0.0021 M (200 ppm), with an efficiency of more than 98%. The results represent the highest amounts of phenol removed from water by membrane or surfactant-mediated separation ever reported.

Measurements of Interface Stress of Silicon Dioxide in Contact with Water−Phenol Mixtures by Bending of Microcantilevers

We use the bending of silicon microcantilevers to measure changes in mechanical stress at interfaces between phenol-water mixtures and SiO(2). The curvature of the microcantilever is measured by an optical system that combines a rapidly scanning laser beam, a position-sensitive detector, and lock-in detection to achieve a long-time stability on the order of 6 mN m(-1) over 4 h and a short-time sensitivity of better than 1 mN m(-1). Thermally oxidized Si shows the smallest changes in interface stress as a function of phenol concentration in water. For hydrophilic SiO(2) prepared by chemical treatment, the change in interface stress at 5 wt % phenol in water is larger than that of thermally oxidized Si by -60 mN m(-1); for SiO(2) formed by exposure of the silicon microcantilever to ozone, the change in surface stress is larger than that of thermally oxidized Si by -330 mN m(-1).