Desorption Of Phenol Research Articles

Design parameters for the treatment of phenolic wastes by carbon columns (obtained from fertilizer waste material)

The waste slurry generated in fertilizer plants in India has been converted into a cheap carbonaceous adsorbent material. The practical applicability of this product has been investigated in the column operations and the mass transfer kinetic approach has been successfully used for the determination of various parameters necessary for designing a fixed bed adsorber. The value of breakthrough capacity is more than the batch capacity. The total time ( t x ) involved for the establishment of the primary adsorption zone (PAZ), the time ( t δ ) required for the movement of PAZ down its length, the fractional capacity ( f), the length of (PAZ) primary adsorption zone ( δ), and percentage saturation of column at break point have been evaluated for carbon columns for the removal of phenols viz., 2,4,6-trinitrophenol, 4-nitrophenol, 4-chlorophenol and 1,3-dihydroxybenzene. Studies have also been performed for the recovery of phenols and chemical regeneration of the spent column. It was observed that 70 mL of 5% w/w NaOH or 50 mL of acetone are sufficient for almost complete desorption of phenols. After regeneration with 1M HNO 3 the sorption capacity of the column is almost the same as that of virgin adsorbent material.

Adsorption of phenol by bentonite

The potential of bentonite for phenol adsorption from aqueous solutions was studied. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, initial concentration, pH, presence of solvent, and the desorption characteristics of bentonite. The adsorption of phenol increases with increasing initial phenol concentration and decreases with increasing the solution pH value. The adsorption process was significantly influenced by the solvent type in which phenol was dissolved. The affinity of phenol to bentonite in the presence of cyclohexane was greater than that in water and was lowest in the presence of methanol. Methanol was used to extract phenol from bentonite. The degree of extraction was dependent on the amount of phenol adsorbed by bentonite. X-ray diffraction analysis showed that the crystalline structure of bentonite was destroyed when cyclohexane was used. The ability of bentonite to adsorb phenol from cyclohexane decreased as the water to cyclohexane ratio was increased. Furthermore, hysteresis was observed in phenol desorption from bentonite in aqueous solutions. The equilibrium data in aqueous solutions was well represented by the Langmuir and Freundlich isotherm models. The removal of phenol from aqueous solutions was observed without surface modification.

Supercritical Extraction of Phenols from Organically Modified Smectite

Supercritical extraction has been performed in a fixed column to desorb phenol and 4-nitrophenol from organically modified smectite. The experiments were carried out in the sequence of adsorption of hexadecyltrimethylammonium (HDTMA) to montmorillonite, adsorption of phenols to organoclay in aqueous solutions, desorption of phenols from loaded organoclay using supercritical carbon dioxide, and adsorption of phenols to regenerated organoclay. The desorption characteristics of phenols were investigated at various pressures up to 420 bar; at temperatures of 40, 60, and 70°C, and at low concentrations of a cosolvent. The extraction percentages of phenols reached up to 90% in 3 hours of extraction. The results showed that under the experimental conditions investigated, the activity of HDTMA was intact during the supercritical extraction of phenols, and hence HDTMA-modified montmorillonite exhibited undiminished adsorption power toward phenols after several regeneration cycles.

Desorption by ultrasound: Phenol on activated carbon and polymeric resin

AbstractAn experimental feasibility study of using ultrasound to accomplish the dificult desorption of phenol from activated carbon and polymeric resin adsorbents is discussed. The desorption rates of activated carbon were found to significantly increase by ultrasound at 40 kHz and 1.44 MHz. Attrition of the activated carbon due to cavitation could be prevented by operating at a higher frequency and with an intensity below the threshold of the pulverization of carbon. According to the structural stability study of Amberlite XAD‐4 and Dowex Optipore L‐493 resins to withstand the abrasive cavitational effects of ultrasound at 40 kHz, the Dowex Optipore resin was stable under experimental conditions and phenol desorption rates were enhanced significantly with sonication. The ultrasonic desorption rates were favored by decreased temperature, aerated liquid medium, and increased ultrasound intensity. The desorption rates obtained without ultrasound appeared to be limited by pore diffusion, whereas those obtained in the presence of ultrasound were limited by surface reaction. The rate enhancement was due to an increase in diffusive transport within the pores caused by acoustic vortex microstreaming. The activation energy for desorption decreased with an increase in ultrasonic power density, thus making the ultrasound weaken the adsorption bond.

Supercritical Fluid Extraction and Temperature-Programmed Desorption of Phenol and Its Oxidative Coupling Products from Activated Carbon

Activated carbon remains one of the most economical adsorbents for the removal of contaminants from water. In particular, activated carbon is known to have an extremely high affinity for phenol and its derivatives. This has been shown to be the result of a catalytic process wherein activated carbon catalyzes the oxidative coupling reactions of phenol in aqueous solution when molecular oxygen is present. These reactions are believed to be the source of the difficulty of regenerating activated carbon loaded with phenol. This paper reports on efforts toward using supercritical fluids to regenerate activated carbon combined with a concurrent temperature-programmed desorption study to identify reaction products and their binding strength to the carbon surface. The results show unequivocally that part of the phenol is chemisorbed on the surface and part of it undergoes polymerization. Dihydroxybiphenyls and phenoxyphenols are the major reaction products present on the surface. Isotope studies showed that surface carbon atoms do not directly participate in these reactions. Supercritical extraction was found to perform as well as solvent extraction for the regeneration of activated carbon loaded with phenol. However, due to the chemisorbed nature of these oxidative coupling products, the reduced mass-transfer limitations afforded by supercritical extraction cannot improvemore » the overall extent of extraction even though the rate is improved with the addition of cosolvents.« less

Detection ofsalmonella typhimurium by hand-held ion mobility spectrometer: A quantitative assessment of response characteristics

Salmonella typhimurium was determined with the use of a combination of an enzyme-linked inmmunosorbent assay (ELISA), a phosphatase mediated end step, and a hand-held ion mobility spectrometer for detecting phenol, the ELISA reaction product. Elevated temperature and low solution pH improved the efficiency for thermal desorption of phenol from filter paper strips; still, the thermal desorption profile was broad and occurred over a 2–3.5-min range. As a result, the detection limits were restricted to ∼104 bacteria in 10-μl aliquots of sample. Precision of quantitative response with a hand-held ion mobility spectrometry (IMS) analyzer ranged from 0.7%–42% relative standard deviation (RSD) for 0–10 μg of phenol, and the precision mean was 12% RSD. Thermal and hydrolytic stability of phenylphosphate, the substrate for ELISA reactions, was excellent in buffer solution, without detectable degradation for over 60 days at temperatures from −70 to 45 °C. Response to increasing levels of S. typhimurium antigen by IMS correlated with a traditional optical spectrophotometric method and showed comparable detection limits. Calculations portend a 100-fold improvement in detection limits through only improved engineering of an ELISA-IMS interface. © 1997 John Wiley & Sons, Inc.

Desorption of Phenol from Activated Carbon by Hot Water Regeneration. Desorption Isotherms

Adsorption of phenol from aqueous solutions at high temperatures on activated carbon was studied. The adsorption capacities were determined by the semicontinuous desorption experiments carried out in a fixed bed adsorber, which was operated in liquid-full mode at a pressure of 25 bar and at temperatures up to 190 °C. It was found that in the range of phenol concentrations from 0.005 to 30 g/L the five-parameter Redlich−Petersen adsorption model is equivalent to the six-parameter Fritz−Schlünder adsorption model when describing liquid−solid adsorption on the Filtrasorb (F-400) activated carbon. By hot water regeneration, 95% recovery of initial adsorption capacity of activated carbon was obtained. It is also demonstrated that the proposed experimental method for determination of adsorption capacities at high temperatures can be used as an alternative to the traditional method by taking breakthrough curves.

Study of the desorption of phenol and phenolic compounds from activated carbon by liquid-phase temperature-programmed desorption

The thermal desorption in water of phenol, 2-dichlorophenol, 2,6-dichlorophenol, 4-nitrophenol and 2,6-dichloro-4-nitrophenol adsorbed onto an activated carbon is studied by temperature-programmed desorption (TPD) in liquid phase and by temperature-programmed adsorption-desorption (TPAD). The TPAD thermograms indicate that the desorption in water of the five compounds is complete before a temperature of 300 °C is reached. The five phenolic compounds are stable below 260 °C. Application of the interruption test shows that diffusion controls the desorption of these compounds in water. High-temperature adsorption isotherms and TPAD thermograms indicate that readsorption occurs during thermal desorption. Study of TPAD permits the calculation of the activation energies of adsorption and desorption. The values of these energies afford values for the adsorption bonding energy that lie within the range of the hydrogen bond.

Optimisation and validation of an automated solid phase extraction technique coupled on-line to enzyme-based biosensor detection for the determination of phenolic compounds in surface water samples

A fully integrated screening system for phenolic compounds was developed incorporating on-line solid phase extraction, fractionation and biosensor detection. Two different types of biosensors, solid graphite and carbon paste electrodes incorporating the enzyme tyrosinase, were compared and used in the screening system. Interfacing of the solid phase extraction and fractionation with the biosensor detection was given special attention since the biosensors were not compatible with the organic modifier used for desorption of phenols from the solid phase extraction step. The system was validated with conventional analytical techniques. Surface water samples from the Ebro river were spiked with 1,10, and 25μg L−1 of catechol, phenol,p-cresol, respectively. Three out of seven samples were spiked and the correct samples were identified, containing phenols equivalent to the spiked concentrations.

Adsorption‐desorption behavior of phenols on novel polymers containing the pyrrolidinone moiety

AbstractCrosslinked polymers having a pyrrolidinone moiety (CPS, CPES, and CVP) were synthesized by radical copolymerization of 4‐(2‐oxo‐1‐pyrrolidinyl)methylstyrene, 4‐[2‐(2‐oxo‐1‐pyrrolidinyl)ethoxy]methylstyrene, or 2‐vinylpyrrolidinone with divinylbenzene in the presence of AIBN as a radical initiator. The adsorption‐desorption behavior of phenols on these polymers was investigated. The polymers with spacers between the polymer main chain and pyrrolidinone moiety appeared to have a superior adsorption capability to those without such spacers. The amount of phenol adsorbed on the polymers in a solvent decreased in the following order: water > chloroform > methanol. In methanol, the interaction between the polymers and phenol was suggested to come only from charge‐transfer stacking (C–T stacking), whereas in chloroform the interaction was caused mainly by both hydrogen bonding and C–T stacking. The interaction in water was attributed not only to both hydrogen bonding and C–T stacking, but also to a hydrophobic interaction. Characterization of polymers (CVP) containing adsorbed phenol was carried out by thermogravimetric analysis (TGA). The TGA curves indicated a two step weight‐decrease, namely the first step in the temperature ranging from ca. 100‐200°C was attributed to the desorption of phenol while the second step in the temperature ranging from ca. 350‐500°C was based on thermal decomposition of the polymers. The desorption of phenol adsorbed on the polymers in water indicated an inverse tendency to the adsorption; that is, the amount of phenol desorbed from the polymers without a spacer was more than those from the polymers with spacers. © 1994 John Wiley & Sons, Inc.

Kinetics of Phenol and Aniline Adsorption and Desorption on an Organo-Clay

The use of organo-clays in wastewater treatment, as alternatives to activated C for sorbing pollutants, and in clay liners is of great interest to soil and environmental scientists. There is a lack of information, however, on the kinetics and mechanisms of organo-clay interactions with pollutants. Accordingly, in this study, the time-dependent adsorption and desorption of phenol and aniline on hexadecyltrimethylammonium-montmorillonite (HDTMA-Montmorillonite) from aqueous solutions were determined in a stirred-flow chamber. The experiments were conducted at two concentration levels, 0.001 and 0.01 mol L-1 for aniline, phenol, and their mixed solutions. Carbon-labeled (14C) solutes were used in the study. Adsorption of both phenol and aniline was completed within 40 min and desorption in 20 min. When the sorptives were mixed, the rates of adsorption-desorption were not significantly affected. The rate of phenol adsorption was influenced by sorptive concentration while the rate of aniline adsorption was independent of sorptive concentration. Various mechanisms appear to be involved in the adsorption processes.

EFFECTIVE DIFFUSIVITY OF PHENOL IN ACTIVATED CARBON

The desorption of phenol from activated carbon in aqueous systems is studied here at various temperatures and adsorbed concentration levels in a stirred batch system. It is found that at sufficiently rapid stirring rates the desorption is controlled by intraparticle mass transfer. The effective diffusivity value is estimated to be 2.1 × 10−10m2/s at 30°C and increases to 6.7 × 10−10m2/s at 80°C, yielding tortuosity values that are essentially temperature independent

Behavior of phenol and aniline on selected sorbents and energy-related solid wastes

The sorption and desorption of phenol and aniline on selected soils and soil components and on some energy-related solid wastes were investigated. Isotherms were generally nonlinear and were described usually by the Freundlich equation. Most partition coefficients were low, and no significant correlation was shown with organic C content, pH, cation exchange capacity, or particle-size of the sorbent. It appears that sorption of small polar aromatic compounds, such as phenol and aniline, cannot be defined by a single sorbent characteristic, but is affected by both the organic and mineral components of the sorbents. Hysteresis was observed in most sorption-desorption experiments; a fraction of the sorbate was irreversibly held by the sorbent.

Solvent regeneration of spent activated carbon in wastewater treatment.

Ethanol regeneration was applied to spent activated carbon which had adsorbed an organic compound in aqueous solutions, including an industrial wastewater. High regeneration efficiency was achieved except for aromatic compounds substituted by electron-donating groups. In the case where ethanol regeneration was not effective, efficient regeneration was possible using an electron-donating solvent such as N,N-dimethylformamide.From the viewpoint of practical use, the solvent regeneration of carbon which had adsorbed phenol was studied using fixed-bed runs. It was found that ethanol and toluene showed high regeneration efficiency. The column desorption of phenol was simulated and gave good agreement with observed results. The regeneration efficiency of ethanol and toluene fell to 80% after five regeneration cycles. The influence of phenol concentration in solvent on the regeneration efficiency was experimentally determined, and the results suggested that the amount of solvent can be minimized by using countercurrent multistage operation.

Temperature-programmed-desorption of phenol from oxide surfaces

Interactions between phenol molecules and surfaces of SiO 2−Al 2O 3 (SA), MgC and ZrO 2 were studied by using a temperature-programmed-desorption (TPD) method and an infrared spectroscopy. Desorption of phenol gave a single peak in the TP[ profiles of SA and ZrO 2 at 363 and 783 K, respectively, but complicated profiles were found on MgO. A part of the adsorbed phenol was found to decompose to benzene and water at 803 K on ZrO 2, 853 K on MgO and above 873 K on SA, Desorption of water was also found below the decomposition temperatures; SA and ZrO 2 gave a similar profile in which the water desorption peak appeared at around 473 K. No desorption of water was found on MgO at lower temperatures for MgO evacuated at 1073 K but a new peak appeared at around 538 K for MgC evacuated at 873 K. The difference in the desorption temperatures on the three samples was explained by considering the individual surface acid-base properties and OH concentration at the surface. The relative difficulty for phenol desorption and easiness for its decomposition on ZrO 2 were interpreted in terms of its weak acid and weak base properties.

Adsorption of organic compounds by microbial biomass

The adsorptive capacity of phenol, chlorophenol, chlorobenzene and ethylbenzene by inert microbial biomass was studied. Desorption and reversibility of adsorption processes were also investigated. The experimental results suggest that the adsorption process of liquid organic compounds can be expressed by the Freudlich Adsorption Isotherm. Sorption capacity is strongly correlated to molecular properties such as water solubility and octanol/water partition coefficient. The combination of lower solubility and higher octanol/water partition coefficient favors the adsorption by microbial biomass. Desorption studies indicated that there are considerable amounts of desorption of phenol and chlorophenol but not chlorobenzene and ethylbenzene. Adsorption by microbial biomass is not completely reversible.

Adsorption and desorption of phenol on anion-exchange resin and activated carbon

Adsorption and desorption of phenol on activated carbon and strong base anion-exchange resin were investigated in a fixed-bed column. Phenol was effectively adsorbed on both adsorbents. Experimental breakthrough curves were compared with values calculated on the assumption of surface diffusion controlling. Two methods of regeneration of adsorbents were carried out, that is, caustic desorption and acid desorption. Regeneration by sodium hydroxide or hydrochloric acid was effectively performed for the resin. On the other hand, regeneration of the activated carbon by sodium hydroxide was not performed completely. The adsorption capacity for activated carbon decreased gradually during the repetition process of adsorption and desorption, while the capacity for anion-exchange resin remained constant. 14 references, 9 figures, 1 table.

Desorption of phenol from activated carbon by solvent regeneration

Desorption of phenol from activated carbon by solvent regeneration

Solvent regeneration of activated carbon

Nineteen solvents were evaluated in batch tests involving the desorption of a representative organic adsorbate (phenol) from activated carbon. Three of the better solvents which also possess complete miscibility with water (acetone, dimethylformamide, methanol) were tested further in fixed-bed runs. The effects of solvent temperature and solvent flow rate on phenol desorption were evaluated. In addition, the recovery of phenol adsorption capacity by an activated carbon bed operated cyclically using a sequence of phenol adsorption, desorption with methanol, and rinsing with water was determined. It was found that solvent temperature and flow rate are not critical variables. Solvent volume and type were the most important factors in phenol desorption. A modest volume of methanol restored 88% of the fixed-bed adsorption capacity for phenol after 1 regeneration, and the capacity essentially leveled off after 5 regenerations at a value of 81% of the capacity of fresh carbon. Methanol regeneration is effective, easy to perform and offers convenient solvent recovery. Thus, it is an attractive alternative to thermal regeneration methods.

ChemInform Abstract: THERMOANALYTICAL STUDY OF ACTIVATED CARBON REGENERATION. I. DESORPTION OF PHENOL AND ANILINE

Chemischer InformationsdienstVolume 10, Issue 31 Article ChemInform Abstract: THERMOANALYTICAL STUDY OF ACTIVATED CARBON REGENERATION. I. DESORPTION OF PHENOL AND ANILINE V. AMICARELLI, V. AMICARELLISearch for more papers by this authorG. BALDASSARRE, G. BALDASSARRESearch for more papers by this authorL. LIBERTI, L. LIBERTISearch for more papers by this author V. AMICARELLI, V. AMICARELLISearch for more papers by this authorG. BALDASSARRE, G. BALDASSARRESearch for more papers by this authorL. LIBERTI, L. LIBERTISearch for more papers by this author First published: July 31, 1979 https://doi.org/10.1002/chin.197931097AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume10, Issue31July 31, 1979 RelatedInformation