Sorption Of Phenol Research Articles

Adsorption of phenol from aqueous solutions by Na–bentonite: kinetic, equilibrium and thermodynamic studies

ABSTRACT Adsorption of phenol from aqueous solution onto the Na-bentonite was investigated in a batch system. Equilibrium, thermodynamics and kinetic studies were conducted by considering the effects of pH, initial phenol concentration, contact time, and temperature. The results showed that the uptake of the phenol increased with an increase in initial phenol concentration. The pH for optimum adsorption was 3 for the phenol (Q = 8.76 mg/g). Langmuir isotherm described the adsorption of phenol onto the Na-bentonite (R2 = 0.93) is better than the Freundlich model (R2 = 0.77). Adsorption kinetics data obtained for the phenol sorption were fitted using pseudo-first-order and pseudo-second-order. It was found that the kinetics data fitted well into the pseudo-second-order kinetics. Thermodynamic parameters such as Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) were evaluated. The result showed that adsorption of the phenol onto Na-bentonite was spontaneous and endothermic in nature. The results indicate that there is significant potential for Na–bentonite as an adsorbent material for phenol removal from aqueous solutions.

Nonlinear sorption of phenols and anilines by organobentonites: Nonlinear partition and space limitation for partitioning

Organobentonites, i.e., bentonites coated with surfactants such as cetyltrimethylammonium (CTAB), are superior and low-cost sorbents for removal of organic contaminants from wastewater. Nonlinear sorption of polar organic compounds such as phenols and anilines by organobentonites were widely observed and interpreted by adsorption mechanism. However, in this study, it was observed that the nonlinear sorption of phenols and anilines by CTAB coated bentonites (CTAB-bentonites) should be attributed to nonlinear partition mechanism with the additional space limitation in CTAB-bentonites for nonlinear partitioning, rather than adsorption mechanism. This nonlinear partition mechanism is supported by that (i) organobentonites is a partition medium, identified by the linear isotherms of polycyclic aromatic hydrocarbons (PAHs) and nitrobenzenes; (ii) sorption coefficients (logKd), the ratio of adsorbed amount (qe) to equilibrium concentration (Ce), and Dubinin-Ashtakhov (DA) model fitted sorption capacity (logQ0) of organic compounds, by a given CTAB-bentonite, are positively correlated with their octanol-water distribution coefficients (logKOW) and solubility in octanol (logSo) respectively; (iii) logKd and logQ0 of a given organic compound by CTAB-bentonites are positively correlated with organic carbon contents (foc) of CTAB-bentonites, but not specific surface area. Specific interaction (i.e., hydrogen-bonding interaction), in addition to van der Waals force, is responsible for the nonlinear partitioning of phenols and anilines into CTAB-bentonites, because of the positively linear relationship between DA model fitted sorption affinity (E) and hydrogen-bonding donor parameter (αm) of organic compounds. These results could help the recognizing of the nonlinear sorption behaviors of organic compounds by organobentonites and promote their environmental applications in wastewater treatment.

Effect of iron treatment and equilibrium pH on the kinetics of removal of some substituted phenols from synthetic wastewater onto Nostoc sp. biomass.

Substituted phenols, such as 4-Nitrophenol (4-NP) and 2,4-Dichlorophenol (2,4-DCP), that are present in industrial wastewaters are considered as priority pollutants due to their toxic effects. Their removal by biosorption presents an eco-friendly, cost-effective method. The kinetics of removal of 4-NP and 2,4-DCP by untreated Nostoc sp. (UNB) and Fe-treated Nostoc sp. biomass (FNB) were studied at three different pH (4.0, 7.0 and 9.0). The highest sorption of both phenols (2.28 mg 4-NP and 1.51 mg 2,4-DCP g-1) coupled with the lowest cumulative percentage desorption was recorded with FNB at pH 7.0. The sorption of both phenols by UNB and FNB was best accounted for by pseudo-second-order kinetics. Compared to UNB, FNB had significantly higher equilibrium sorption capacities for both phenols at all the three pH values and also higher sorption rate constants of 4-NP at pH 4 and 9 and of 2,4-DCP at pH 4 and 7. The Fourier transform infrared spectroscopy (FTIR) analysis showed that -OH and COO- groups of UNB interacted with Fe+3. The sorption of 4-NP and 2,4-DCP on UNB was likely through H-bonding/structural cation bridging with the phenolic group, while their sorption onto FNB appeared to be a complexation reaction with very low reversibility.

The capacity of mesoporous fly ash grafted with ultrathin film of polydiallyldimethyl ammonium for enhanced removal of phenol from aqueous solutions

This study investigates the feasibility of coating cationic polydiallydimethyl ammonium chloride (PDDA) onto mesoporous acid-treated fly ash (AFA) and its capacity to adsorb phenol from aqueous solution. The PDDA-FA and its AFA substrate were characterized using a scanning electron microscope with energy-dispersive x-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and thermogravimetric analysis (TGA) to ascertain successful film coating. Batch adsorption studies were carried out to evaluate the effects of solution pH, initial concentration, adsorbent dosage, contact time, shaking speed and temperature on the removal of phenol using PDDA-FA and AFA. Characterization revealed that the coating of cationic polyelectrolyte film onto FA introduced surface polarity which enhanced the mass transfer of phenol to the PDDA-FA surfaces. Importantly, the results showed that synthesized PDDA-FA is 4-fold more efficient than precursor AFA in removing phenol from aqueous solution. The sorption equilibrium isotherm of adsorbent was described by Freundlich, Langmuir and Temkin models. The adsorption rate of both adsorbents followed the pseudo-second-order kinetic model, while the thermodynamic studies of PDDA-FA sorption of phenol indicated a favorable endothermic and physical adsorption mechanism. The PDDA-FA also has a higher adsorption capacity than other reported modified FA. In conclusion, an ultrathin coating of fly ash with cationic polyelectrolyte offers a viable potential as an alternative adsorbent from waste. This work has the advantages of cleaner production of adsorbents from waste, and wastewater decontamination.

The modified Song isotherm model: application to multisolute sorption of phenols in organoclays using the ideal adsorbed solution theory

ABSTRACT The three-parameter (K, b, and n) Song isotherm model was slightly modified to make it possible to obtain analytical integration of the spreading pressure integral. The modified Song model (MSM) allows more efficient and accurate calculation of the ideal adsorbed solution theory (IAST). The MSM also satisfies the Henry’s law and the Freundlich model at low and high concentrations, respectively, and reverts to the Langmuir and the linear models when n equals zero and one, respectively. Approximate values of each parameter could be estimated from a plot of log (q/c) versus log c; the partition coefficient in the Henry’s law region (K) and the Freundlich index (n) can be estimated from the ordinate value of the low-concentration asymptote and the slope of the high-concentration asymptote, respectively, and the parameter (b) can be estimated from the solution-phase concentration of the intersection point of the two asymptotes. The MSM was fitted to the single-solute sorption of 2-chloro-, 3-cyano-, and 4-nitrophenol onto montmorillonites modified with either HDTMA cation or TMA/HDTMA dual cations. The ideal adsorbed solution theory (IAST) combined with either dual-mode model, Khan model or MSM as a single-solute isotherm model was used to predict three bisolute and one trisolute sorption to organoclays. The Sheindorf-Rebhun-Sheintuch (SRS) and Murali-Aylmore (M-A) were also used to predict bisolute sorption to organoclays. The IAST predictions were generally in good agreement with the multisolute sorption data. The advantages of MSM over other three-parameter models were fully discussed.

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.

Extraction of Phenols From Aqueous Solutions by Magnetic Sorbents Modified with Humic Acids

Sorption of phenol, 4-nitrophenol, pentachlorophenol, and nonylphenol is studied using a magnetic sorbent based on Fe3O4 nanoparticles modified with humic acids (HAs) isolated from various natural sources (brown coal, peat, chernozem, and sapropel). The properties of the resulting sorbents, namely, specific surface area, saturation magnetization, and content of hydroxyl and carboxyl groups, as well as nitrogen, are studied. The best conditions for the extraction of all phenols are achieved at pH 3–6, except for pentachlorophenol, for which the highest degree of extraction is achieved at pH 3–4. The maximum recoveries of phenol, 4-nitrophenol, pentachlorophenol, and nonylphenol are 61, 68, 89, and 94%, respectively.

Enhanced removal of phenol by novel magnetic bentonite composites modified with amphoteric-cationic surfactants

Magnetic bentonite (MBent) was modified by both amphoteric surfactant (BS) and cationic surfactant (CT). The structural characteristics of BS-CT-MBent were explored along with the factors primarily influencing their effectiveness in phenol sorption. The results indicated that BS-CT-MBent showed high separation potential and good stability. The carbon contents of BS-CT-MBent increased while specific surface areas decreased with increasing the BS and CT loading level. The sorption capacities of BS-CT-MBent for phenol (198.74–205.81 mmol kg−1) were improved compared to MBent (16.34 mmol kg−1). The phenol sorption capacities on BS-CT-MBent increased with an increase of BS or CT loading level, while the phenol sorption efficiency decreased at high BS and CT loading level. The phenol sorption capacities decreased with an increase of pH, temperature and with a decrease of background electrolyte concentration. Hydrophobic phases formed by surfactants were the main phenol sorption domains and the hydrophobic partition was the key mechanism.

Activated carbons synthesized from unaltered and pelletized biomass wastes for bio-tar adsorption in different phases

The activated carbons were synthesized from rice husk (RH) and rice husk pellet (RHP) by the two-step pyrolysis (carbonization followed by KOH activation). Based on their textural properties, the activated carbons were comparatively studied for sorption of phenol (tar model compound) in different phases. The surface area (SBET) and pore volumes of RH and RHP chars could be significantly improved with increasing the amount of KOH. Particularly, the RH char-3 showed a highest SBET (1818.45 m2/g) with a higher micro-porosity (93.3%), so the KOH activation of RH char favored the development of microporous structures. Compared with the RH char-3, the RHP char-3 with relatively low SBET (1320 m2/g) showed a meso-microporous structure along with a lower micro-porosity (69.2%), contributing to a higher breakthrough adsorption capacity (740 mg/g) of gaseous phenol. Generally, the adsorption capacity of phenol in the gas phase was higher than that in the liquid phase. RHP favored to form the hierarchical porous carbon enhancing the phenol molecules transportation via the outer layer and then the phenol molecules uptake by the adsorption sites on the inner layer. Also, the appropriate moisture in biochar benefited for adsorption, while the excessive water formed the liquid film, controlling the molecules transport.

Fabrication of novel chitosan-g-PNVCL/ZIF-8 composite nanofibers for adsorption of Cr(VI), As(V) and phenol in a single and ternary systems

The chitosan-grafted-poly(N-vinylcaprolactam) (chitosan-g-PNVCL) nanofibers were synthesized via electrospinning method. ZIF-8 metal-organic frameworks nanoparticles were incorporated into the nanofibers for adsorption of Cr(VI), As(V) and phenol from water. The BET, FTIR, XRD and SEM analysis were carrfried out to obtain the characteristics of nanofibers. The optimum parameters of ZIF-8 content, pH, contact time, adsorbent dosage, and initial concentration of adsorbates on the Cr(VI), As(V) and phenol removal were studied. The reusability of synthesized nanofibers for five sorption-desorption cycles was also examined. The maximum experimental adsorption capacity of the chitosan-g-PNVCL/ZIF-8 nanofibers for Cr(VI), As(V) and phenol sorption were 269.2, 258.5 and 152.3 mg g−1, respectively under ZIF-8 concentration of 3 wt.%, adsorbent dosage of 0.5 g/L, pH of 3, equilibrium times of 30 min, and temperature of 25 °C. The kinetic, and isotherm parameters of adsorption process using chitosan-g-PNVCL/ZIF-8 nanofibers were evaluated. In ternary system, the central composite design was applied to investigate the interaction influence of initial concentrations of selected metal ions and phenol on the performance of nanofibrous adsorbent. The obtained results showed the high capability of nanofibers for the removal of heavy metals and organic pollutants from water.

Synthesis and properties of alumina-hydroxyapatite composites from natural phosphate for phenol removal from water

Phenol is very abundant in the aquatic environment and therefore requires an effective treatment using porous and low-cost adsorbents. Alumina-hydroxyapatite composites were prepared from natural phosphate ore in the presence of Al3+ ions via a wet-chemical method. Porous composites were characterized and the Al-surface modification was produced by facile and inexpensive route to uptake adjacent toxic species. Supplementary active sites on their surface may improve their phenol remediation. Nanocomposites exhibit higher phenol sorption rates than pure hydroxyapatite. It is concluded that the specific surface area, surface charge and Al content are suitable for phenol removal from aqueous solution using Alumina-hydroxyapatite composites. The results show that the retention power of these composites depends on a complex interaction between intermolecular and molecule-solid interactions. These findings are relevant to better understand the contribution of alumina content in Alumina-hydroxyapatite composites to the fate and uptake of phenol from aquatic environments.

Synthesis of high-performance hierarchically porous carbons from rice husk for sorption of phenol in the gas phase

Phenol as a semi-volatile organic compound (SVOC) extensively presents in industrial wastewater. Moreover, it is a main compound of tar existing in the vapor phase from biomass pyrolysis or gasification. So far, most of works on the phenol adsorption by activated carbons have been conducted in the liquid phase. However, the adsorption of phenol in the gas phase has not been reported. This work aims to synthesize the hierarchically porous carbons from the unaltered and pelletized rice husk (RH) via a facile pyrolysis followed by the ball-milling-assisted KOH activation. Herein, the silica nanoparticles in RH acted as a self-template to remarkably increase specific surface areas and pores, thereby giving rise to the formation of hierarchically porous carbons, which showed a relatively high adsorption capacity (maximum value: 1919 mg/g) of phenol in the vapor phase. Generally, the process of phenol adsorption onto porous carbons in the gas phase followed with various interactions, including pore filling, electrostatic interaction, hydrophobic effect, and functional groups effect (e.g., π-π interaction). And the pseudo-second-order model could well describe the adsorption kinetic. It is noted that the pelletized RH was more favorable to develop the porous carbons with the hierarchically meso-microporous structures that could enhance the transfer of the phenol molecules via the outer layer and subsequent uptake by the adsorption sites on the inner layer. Further, the SVOC phenol was hard to volatilize under ambient conditions due to its relatively higher boiling point (181.7 °C), so the thermal desorption was a potential way to regenerate the spent activated biochars.

Sorption Properties of Polydivinylbenzene Polymers Towards Phenolic Compounds and Pharmaceuticals

Highly cross-linked polymers are commonly used in purification and separation techniques because of their many useful features. In order to better adjust their porosity to adsorption of specific compounds, methods like surface functionalization or imprinting are used. In this work, a series of highly cross-linked polydivinylbenzenes (pDVB) were prepared using a suspension method. Toluene was applied as a pore-forming diluent. Some part of toluene (1 mL) was replaced with phenol (F), 2,4,6-trichlorophenol (T) or their mixture (M) to prepare polymers with porosity more suitable for phenols sorption. Another approach was an introduction of sulfone groups onto the polymer surface (pDVB-SO3H). The physicochemical characteristics of the synthetized adsorbents included CHN, FTIR, DSC and porosimetric analyses. Afterwards, to evaluate sorption properties of the prepared adsorbents towards phenols, ibuprofen and salicylic acid the solid phase extraction (SPE) experiments were performed. The polymers had the specific surface areas of about 440–560 m2/g created mainly by mesopores with widths ca. 3.75 and 4.75–7.15 nm. Materials obtained with the addition of porosity modifiers (phenol, trichlorophenol, mixture) had more uniform porous structure and their sorption capacity toward phenols increased ca. 5%. Similar sorption capacities were obtained for ibuprofen. Salicylic acid had low affinity to the surface of the tested polymers.

Ресурсосберегающая технология обезвреживания фенолсодержащих промышленных сточных вод

We have developed a resource-saving, low-waste technology for the disposal of highly toxic phenol-containing wastewater that enables to utilize phenol and formaldehyde as an organic binder. The technology involves the use of technogenic raw materials («overresin» water from the production of phenol-formaldehyde resins, soft wood waste, waste from the production and processing of laminated plastics) and processes of regeneration, recovery and conversion of phenol. The optimal technological parameters of phenol sorption on wood sorbent and secondary poly/condensation were experimentally established. This in turn provides a high degree of neutralization and extraction of resin-forming components from wastewater and subsequent production wood-polymer thermoplastic structural composite and sodium phenolate on their basis.

Analysis of structure and properties of DVB\u2013GMA based porous polymers

Polar porous polymeric microspheres divinylbenzene–glycidyl methacrylate (DVB–GMA) were synthesized with a suspension method. Two kinds of polymers differing in chemical composition and physical properties were obtained. The molar ratios of monomers in the polymers were 50:50 and 75:25, respectively. Next, the prepared materials were chemically treated with phosphoric or sulphuric acid in order to additionally modify their surface. Consequently, the polymers gained acidic character and cation exchange properties. The prepared materials were characterized by: elemental analysis, ATR-FTIR, DSC, low temperature nitrogen sorption and SPE experiments. CHN and ATR-FTIR confirmed the chemical structures of the polymers. The DSC analyses revealed their network was highly cross-linked. Porous structure parameters of the studied materials strongly depended on their chemical composition. All the materials were mesoporous with bimodal pore size distribution (3.7 nm and 5.5–7.5 nm). Highly cross-linked DVB–GMA 75:25 and its acidic derivatives had twice higher specific surface areas (320–370 m2/g) than their less cross-linked counterparts DVB–GMA 50:50 (140–190 m2/g). The prepared materials were tested for the sorption of phenolic compounds (phenol, 2-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol) and popular pharmaceuticals—aspirin, paracetamol and ibuprofen. The process of dynamic sorption of phenols depended on both porous structure and surface chemistry of the polymers. And the less polar character of the polymeric surface was balanced by its higher porosity to maintain the sorption ability on the same level. In case of pharmaceuticals dependence of sorption properties on porosity and/or surface chemistry was more diversified and additionally chemical nature of adsorbate had to be taken into account.

Purification of aqueous media from toxicants carbon-mineral sorbent

To purify aquatic environments from various toxicants, we obtained a carbon-mineral sorbent from the reed stems of the South (Phragmitesaustralis) by carbonization. At the stage of carbonization of the crushed reed, a carcass, containing carbon and silicate constituents, is formed. Depending on the type of feedstock and the carbonization temperature of the organic component, the content of the silicate component varies in the range of 20-30%. The process is carried out until a sorbent containing 70-80% of the carbon component, 29-19% of the silicate component and 1% of water is obtained. The adsorption capacity of the obtained carbon-mineral sorbent towards to medium and macromolecular organic compounds, and heavy metals was studied. As a result, it was established that the carbon-mineral sorbent obtained from the reed stems of the South (Phragmitesaustralis) has moderately distributed sizes of macro- and micropores. The presence of two constituents, carbon and silicate, in the structure of the obtained sorbent promotes the sorption of phenols, hydrocarbons, barbiturates, cholesterol derivatives, aminoglycosides, anthracyclines and other compounds, as well as ions of heavy metals, which makes it possible to use a sorbent in the chemical industry for purification of sewage, natural waters and it can be proposed for the purification of biological fluids.

Sorption, kinetic, thermodynamics and artificial neural network modelling of phenol and 3-amino-phenol in water on composite iron nano-adsorbent

Sorption, kinetic, thermodynamics and artificial neural network modelling of phenol and 3‑amino‑phenol in water on composite iron nano-adsorbent are described. The optimized conditions were 100g/L conc., 40min contact time, 11 pH, 5mg/10mL nanoparticles amounts, and 298K temperature. The data followed Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models. The values of ΔG0 (average value=−7.14kJmol−1 for phenol and 7.07kJmol−1 for amino-phenol), ΔH0 (−4.92kJmol−1 for phenol and−4.00kJmol−1 for amino-phenol) and ΔS0 (−7.0×10−3kJmol−1K−1 for phenol and 6.89×10−3 for amino-phenol) confirmed spontaneous adsorption. The mechanism of sorption was through film diffusion. The maximum percent uptakes of phenol and p‑amino‑phenol and were 85.0 and 80.0%. The method is fast, economic and capable to work at natural water pH. Therefore, the presented method may be used for the removal of phenol and amino-phenol from any water source.

Cationization of celluloisc fibers in respect of liquid fuel purification

Abstract Fuel upgrading is one of the globally requirements due to struggle the environmental impacts and to protect the humanity. Presence of oxygenated compounds such as phenol in liquid fuel caused serious problems in the fuel combustion and gums formation in the interior engines and consequently blocking the fuel filter. These problems are directly affected on both of the human's life and environment. Herein, functionalized viscose fibers were designed and applied for liquid fuel purification from phenol. Viscose fibers was firstly cationized by interaction with N-2-chloroethyl N,N diethyl ammonium chloride to produce cationized fibers with nitrogen contents of 0.32–0.52%. Sorption of phenol from n-octane by using the cationized fibers was systematically studied. Sorption capacities were significantly affected by the degree of substitution and were linearly increased with nitrogen contents. The maximum sorption capacities were 178.6 and 206.2–282.5 mg/g for untreated and cationized fibers, respectively. Sorption was obeyed to pseudo-second order and signified that cationization process accelerates the phenol removal process. Sorption of phenol onto fibers were well followed Langmuir isotherm profile which reflected the monolayer sorption. Sorption was taken place via weak interactions between phenol molecules and substituted functional groups of fibers achieving physisorption process. However, the maximum capacity was diminished by regeneration process, the maximum removal of phenol was 80% after 4 regenerated cycles. Cationized viscose fibers can be considered as quite good template to purify liquid fuel from phenols, able to apply several times with good economic viability.

Comparison of Amphoteric-Cationic and Amphoteric-Anionic Modified Magnetic Bentonites:Characterization and Sorption Capacity of Phenol

Magnetic bentonite is modified by an amphoteric surfactant (dodecyl dimethyl betaine, BS-12), then modified by a cationic surfactant (Cetyl Trimethyl Ammonium Bromide, CTMAB) and anionic surfactant (Sodium lauryl sulfonate, SDS). Amphoteric-cationic modified magnetic bentonite (BS-CT-MBT) and amphoteric-anionic modified magnetic bentonite (BS-SDS-MBT) are obtained. Structural identification of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analyses (TG), Fourier transform infrared spectra (FTIR), and vibrating sample magnetometer (VSM). The carbon-nitrogen content, specific surface area, and pore volume were also evaluated. Batch isotherm studies were conducted to evaluate the sorption of phenol. The results show that BS-CT-MBT and BS-SDS-MBT can be separated by magnetic separation. The carbon content-nitrogen content and content of surfactants of the BS-CT-MBT increase, while surface area and pore volume decrease compared to those of BS-MBT. Compared with BS-MBT, the carbon-nitrogen content, content of surfactants, and pore volume of BS-SDS-MBT are decreasing and surface area is increasing. The desorption rate of the surfactants is less than 9% at pH 6.0 and in 0.1 mol·L-1 NaCl solution. The Henry equation is the optimal description for the phenol sorption isotherms, implying a partitioning sorption process. The amount of phenol sorption follows the order:BS-CT-MBT > BS-MBT > BS-SDS-MBT > BT > MBT, which significantly correlates with the variation of the content of surfactant. Amphoteric magnetic bentonites modified by CTMAB have better absorption performance for phenol than those modified by SDS.

Recovery of Phenols From Waste Waters by an Encapsulated Magnetic Sorbent

Magnetic nanoparticles of an iron oxide (Fe3O4) encapsulated in hyper-cross-linked polystyrene (PS) were used as a sorbent for recovery of phenols from waste waters. The encapsulated magnetic sorbent Fe3O4-PS was prepared by suspension polymerization. Sorption of phenol and 4-nitrophenol onto Fe3O4-PS was studied under dynamic and static conditions. The recovery of 4-nitrophenol was 96%; of phenol, 64%.