Adsorption Isotherms Of Phenol Research Articles

Development of Molecularly Imprinted Polymer in Porous Film Format for Binding of Phenol and Alkylphenols from Water

Molecularly imprinted polymers (MIPs) were fabricated on glass slides with a “sandwich” technique giving ~20 μm thick films. Methanol/water as a solvent, and polyethyleneglycol and polyvinylacetate as solvent modifiers, were used to give a porous morphology, which was studied with scanning electron microscopy and gravimetric analysis. Various MIPs were synthesized through non-covalent imprinting with phenol as the template; itaconic acid, 4-vinylpyridine, and styrene as monomers; ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and pentaerythritol triacrylate (PETA) as cross-linkers. Binding and imprinting properties of the MIPs were evaluated based on phenol adsorption isotherms. Since phenol has only one weakly acidic hydroxyl group and lacks unique structural characteristics necessary for binding specificity, the preparation of selective MIPs was challenging. The recognition of phenol via hydrogen bonding is suppressed in water, while hydrophobic interactions, though promoted, are not specific enough for highly-selective phenol recognition. Nevertheless, the styrene-PETA MIP gave modest imprinting effects, which were higher at lower concentrations (Imprinting Factor (IF) = 1.16 at 0.5 mg·L−1). The isotherm was of a Freundlich type over 0.1–40 mg·L−1 and there was broad cross-reactivity towards other structurally similar phenols. This shows that phenol MIPs or simple adsorbents can be developed based on styrene for hydrophobic binding, and PETA to form a tighter, hydrophilic network.

Development of olivestones-activated carbons by physical, chemical and physicochemical methods for phenol removal: a comparative study

ABSTRACTOlive stones, an agricultural waste, have successively undergone a chemical activation by ZnCl2 (coals CZ), a physical activation by CO2 (coals CP) and a combined activation by ZnCl2 followed by CO2 (coals CC) in order to compare the efficiency of these activating agents in the production of activated carbons for their applications in polluted water treatment. The obtained results show that the larger the ratio of ZnCl2 to olive stones (coals CZ and CC), and the duration of preservation of CO2 (coals CP), the more developed the porous texture. These results are confirmed by immersion calorimetry in cyclohexane and tri-2,4-xilyl phosphate. The adsorption of phenol in aqueous solution on all activated carbons at 25°C was investigated. The adsorption kinetics data were well described by the pseudo-second-order model, and all phenol adsorption isotherms on various activated carbons perfectly fit the Langmuir equation. Furthermore, the phenol adsorption capacities of activated carbons obtained by physi...

Adsorption behavior of phenol on activated carbons prepared from Algerian coals

Activated carbons were prepared by chemical activation of two Algerian coals (Menouna and Didi), using different chemical agents: Cs2CO3, Rb2CO3, and H3PO4. The mass losses during pyrolysis of the two coals are perfectly correlated to the heat of immersion of the obtained materials in the benzene; indeed, effective activation leads to important weight loss, developed porosity and then easy wetting by benzene. Besides, the obtained results show that the cesium hydroxide is the most effective activating agent. The efficiency of this last one is confirmed by the phenol adsorption isotherms which show a bigger capacity of adsorption. Finally, the values of adsorption capacities of the obtained activated charcoals, toward the phenol, are higher than those of the coals obtained without activating treatment.

Adsorption of phenol with the crosslinked polymer of P(MMA-MAh)-PEG33

ABSTRACTThe adsorption of phenol with the crosslinked polymer of P(MMA-MAh)-PEG33 was studied. Through the research, it was found the adsorption was favored in acidic aqueous solution and almost needed 35 h to reach the equilibrium. The calculated thermodynamic parameters suggested that the adsorption of phenol onto P(MMA-MAh)-PEG33 was spontaneous and exothermic in nature. From the kinetic research, the adsorption of phenol with the crosslinked polymer belonged to the first-order reaction. The adsorption isotherms of phenol with polymer well accorded with the Freundlich model.

Adsorption of phenol and 1-naphthol onto XC-72 carbon

XC-72 carbon (XC-72) was characterized by SEM, XPS, N2 adsorption-desorption, particle size distribution analysis and potentiometric acid-base titration. The adsorption of phenol and 1-naphthol on XC-72 was studied as a function of contact time, pH, adsorbent content and temperature. The kinetic adsorption data were described well by the pseudo-second-order model. The adsorption isotherms of phenol were described well by Freundlich model, while the adsorption isotherms of 1-naphthol were fitted well by Langmuir model. The results demonstrated that XC-72 had much higher adsorption capacity for 1-naphthol than for phenol. The adsorption thermodynamic data were calculated from the temperature-dependent adsorption isotherms at T=293, 313 and 333 K, and the results indicated that the adsorption of phenol was an exothermic process, whereas the adsorption of 1-naphthol was an endothermic process. XC-72 is a suitable material for the preconcentration of phenol and 1-naphthol from large volumes of aqueous solutions.

TSMBC(Thermal Simulated Moving Bed Concentrator)를 이용한 페놀 농축

일반적인 SMB 공정은 여러 개의 크로마토그래피 컬럼을 갖는 4개의 구역으로 구성되어 있다. SMB는 회분식 크로마토그래피와는 달리 연속적으로 이성분계 물질 분리가 가능한 것이 가장 큰 장점이다. SMB 공정을 이용하여 목적 물질의 높은 생산성과 높은 순도의 물질을 얻어낼 수 있다. 이러한 SMB의 특징을 더욱 부각시키려는 연구들이 현재 진행되고 있다. 본 연구에서는 기존 SMB 공정에 온도의 변화를 추가한 Thermal Simulated Moving Bed Concentrator (TSMBC) 공정의 모사를 연구하였다. TSMBC의 장점으로는 온도의 변화를 통하여 등온 흡착식의 조작을 가할 수 있으며, 목적 물질에 따른 적용 분야가 다양하다는 것이다. 본 연구에서는 환경 친화적 공정으로 TSMBC의 적용 가능성을 시험하기 위해서 페놀 폐수로부터 순수한 용매인 물을 얻어내고 용질인 페놀은 농축시키는 모사 과정을 연구하였다. 고정상과 목적물질인 DOWEX <TEX>$1{\times}4$</TEX>와 페놀을 선정하고 고정상에 대한 페놀의 등온 흡착식을 측정하였다. 모사 과정에서는 총 세 가지 종류의 컬럼을 사용하였고 주입 시료 대비 2.29배, 2.28배, 그리고 1.31배의 목적 물질 농축을 확인할 수 있었다. 그러나 solvent port에서 용질의 배출도 발견되어 DOWEX <TEX>$1{\times}4$</TEX> 고정상이 상온에서 갖는 페놀의 흡착식에 대한 한계점을 확인하였다. Conventional SMB process is operated using 4-zone having several chromatography columns in each zone. Unlike batch chromatography, SMB process can continuously separate binary materials. Both high productivity and purity are obtainable by using SMB process. In this study, the simulation on Thermal Simulated Moving Bed Concentrator (TSMBC) which is a SMB process with thermal swing adsorption was carried out. The advantage of TSMBC is that adsorption isotherm can be easily controlled by thermal wave or direct heating. Recovery of pure water and concentration of phenol was studied in simulation. To verify environmental-friendly potential of TSMBC, DOWEX <TEX>$1{\times}4$</TEX> was chosen as an adsorbent and phenol was selected as a target material. When 3 columns were used in this study, concentration of phenol is 2.29, 2.28 and 1.31 times higher than injected sample. However, a contamination of phenol in solvent port was found, probably due to the restriction of adsorption isotherm of phenol on DOWEX <TEX>$1{\times}4$</TEX>.

Adsorption Isotherms of Phenol Onto Adsorbents Derived from Egg Shell and Palm-Oil Shell

The adsorption isotherms of phenol from aqueous solution onto adsorbents obtained from egg shell (ESA) andpalm shell (PSA) were investigated. The objectives of the investigation were to understand the effect of bothadsorbents on solution pH and to study the adsorption equilibrium of phenol onto the adsorbents. The effect ofadsorbent on pH of solution was studied by shaking the adsorbent of 0.1 to 1.5 g with 100 ml of acidic aqueoussolution for 30 min at room temperature. The adsorption experiments were performed by stirring appropriateamount of adsorbent with 100 ml of 50 mg/l concentration of phenol at constant temperature and pressure. TheLangmuir and Fraundlich adsorption models were applied to experimental data and the isotherm constants werecalculated using linier regression analysis. The results showed that the adsorption capacity of the adsorbentsincreases with increasing of dosage and contact time. Also, pH of solution affected the adsorption isotherm ofphenol, where maximum adsorption was observed at pH values lower than 9.

Preparation, characterization, and phenol adsorption of activated carbons from oxytetracycline bacterial residue

The oxytetracycline bacterial residue–activated carbon (OBR-AC) prepared from oxytetracycline bacterial residue with K2CO3 under chemical activation was studied. The effects of activation temperature, activation time, and activation ratio on the specific surface area (SSA) and methylene blue adsorption (MBA) were studied. Characterization of the optimum OBR-AC was performed by using scanning electron microscopy (SEM), pore structure (PS,) and Fourier-transform infrared spectroscopy (FT-IR). The optimum parameters were as follows: 800°C activation temperature, 3 hr activation time, and 1:3 activation ratio. The SSA and MBA under optimum conditions were 1593.09 m2/g and 117.0 mg/g, respectively. Adsorption equilibrium and kinetics data were determined for the adsorption of phenol from the synthetically prepared phenol solution. The results showed that the Langmuir model gave the best fit for equilibrium isotherm, whereas the kinetics data were well fitted by the pseudo-second order model. Implications In the past, the bacterial residues have been used for feed additives in China. Unfortunately, doubts of its suitability as a feedstock have been raised because of the small amount of antibiotics, a large number of the fermentation by-products and metabolic products and by-products remaining in the bacterial residues. So Oxytetracycline Bacterial Residue (OBR) is one of hazardous wastes in China. In order to solve the problem of OBR, the preparation of OBR-AC is studied, and OBR-AC under optimum operation parameters is characterized by Scanning Eldctron Microscopy (SEM), Pore Structure (PS) and Fourier Transfer-Infra Red (FT-IR). Moreover, the phenol adsorption isotherms and kinetics models for OBR-AC under optimum operation parameters are studied.

The Use of Sawdust as by Product Adsorbent of Organic Pollutant from Wastewater: Adsorption of Phenol

Locally available sawdust, a very low cost and promising material was tested experimentally as an adsorbent, after carbonization, for the removal of phenol from industrial waste waters for a safe disposal. The experiments were performed batchwise to remove phenol from synthesized aqueous solutions. The equilibrium adsorption level was determined as a function of the solution pH, temperature, contact time, adsorbent dose and the initial adsorbate concentration. Adsorption isotherms of phenol on adsorbents were determined and correlated with the usual isotherm equations such as Langmuir and Freundlich. The optimum conditions for the removal of phenol were worked out along with the kinetics of the process.

Thermodynamics of Phenol Adsorption onto Activated Carbon Fiber

The adsorption of phenol onto activated carbon fiber (ACF) from aqueous solutions were studied. The adsorption isotherms of phenol onto ACF at 298.15 K,303.15 K and 308.15K follow the Freundlich and Langmuir isotherm equation. The Freundlich model was verified to be the best to describe the adsorption data.Values of ∆G0 for phenol adsorption onto ACF are-8.549、-7.899 and -7.516 kJ•mol-1 at 298.15,303.15and 308.15K , respectively. The values of ∆H0 and ∆S0 are -39.30 kJ•mol-1 and -103.3 J.mol-1.k-1, respectively. The adsorption process is spontaneous and exothermic. Negative △S0 values suggested the randomness of phenol molecules at solid-liquid interface and an decrease in the degree of freedom of the adsorbed species.

Adsorption of phenol onto surfactants modified bentonite

Bentonite was modified with hexadecyltrimethylammonium bromide or bencylhexadecyldimethylammonium chloride. Phenol adsorption kinetic and isotherms experiments were performed; in both cases, phenol was determined in the aqueous solutions by UV–Vis spectroscopy. The results showed that the adsorption of phenol depends on the kind of surfactant, and pH of the solutions. The adsorption was higher for the clay modified with bencylcetyldimethylammonium chloride than hexadecyltrimethylammonium bromide.

Adsorption behavior of phenol for mono, bis and tris (2,2' -bipyridine )nickel (II )- and tris(ethylenediamine)nickel(II)-saponite intercalation compounds from aqueous solution

Adsorption of phenol on mono, bis and tris(2,2'-bipyridine)nickel(II)- and tris(ethylenediamine)-nickel(II)-saponite intercalation compounds from aqueous solution was examined. Mono, bis and tris(2,2'-bipyridine)nickel(II)-saponites were prepared by the reactions of Ni(II)-form of a synthetic saponite (Sumecton SA) with 2,2'-bipyridine at the molar 2,2'-bipyridine to Ni(II) ratios of 1:1, 2:1 and 3:1. Tris(ethylenediamine)nickel(II)-saponite was prepared by the reactions of the Ni(II)-saponite with ethylenediamine at the molar ratio of 3:1 (ethylenediamine:Ni(II)). X-Ray diffraction and thermal analysis indicated that 2,2'-bipyridine and ethylenediamine were intercalated into Ni(II)-saponite to form mono, bis and tris(2,2'-bipyridine)nickel(II) and tris(ethylenediamine)nickel(II) complexes. The adsorption isotherms of phenol for the mono, bis and tris(2,2'-bipyridine)nickel(II)-saponites followed Langmuir type, indicating strong adsorbate-adsorbent interactions. The basal spacings of the mono, bis and tris(2,2'-bipyridine)nickel(II)-saponites did not change by the adsorption of phenol, indicating that the adsorbed phenol existed in the interlayer micropore formed by the pillaring with the complexes. The adsorption of phenol on the tris(ethylenediamine)nickel(II)-saponite was less effective than those on the (2,2'-bipyridine)nickel(II)-saponites, suggesting that the interactions between pyridine rings and phenol played an important role in the adsorption of phenol.

Study of Control for Phenol and Chlorophenols Sudden Pollution in Drinking Water by Using PAC Adsorption

Phenol and chlorophenols (CPs) are main toxic organic pollutants detected generally in source water. In the present studies, removal efficiency of phenol and CPs by using PAC adsorption was investigated, base on the control of drinking water sudden pollution. The results showed that the removal of phenol and CPs was essentially complete within 2 hours, and that the adsorption ratio in proper order was: 2, 4, 6- TCP &gt; 2, 4- DCP &gt; 2- MCP &gt; PCP &gt; phenol. The adsorption isotherm of phenol and CPs by PAC was consistent with the Freundlich and Langmuir adsorption mode. The study on the raw water collected from a lake in a university also provided the evidence that water quality affected the adsorption rate and adsorption capacity apparently. The phenol and CPs in sudden water pollution accidents was removed by addition of 20mgL-1 PAC. Results provided technical solution for water pollution accidents to cope with phenol and CPs sudden.

Adsorption heats of phenol on activated carbon using adapted method of immersion calorimetry

Simple adaptation of the technique of immersion calorimetry enables determining both integral and differential adsorption heats as well as the course of the adsorption isotherm of phenol on activated carbon. The innovative aspect of the applied procedure consists in bringing the phenol aqueous solution to contact with the suspension of carbon with water. Thus, the “interfering” heat effect of carbon interaction with water is eliminated, and only the net adsorption heat of phenol is monitored. The value of −52.5 kJ mol−1 was ascertained as the molar differential adsorption heat at the low surface coverage (cca 0.2 mmol g−1) of the sample of microporous carbon. As the adsorption process continues, for adsorption uptakes exceeding the value of about 1 mmol g−1, molar differential adsorption heats appear to be established at a level of about −20 + 5 kJ mol−1.

Adsorption of Phenol and Basic Dye on Carbon Nanotubes/Carbon Fabric Composites from Aqueous Solution

The liquid-phase adsorption of phenol and dye (basic violet 10) onto carbon nanotube (CNT)-activated carbon fabric (ACF) composites, prepared by a catalytic chemical vapor deposition (CCVD) approach, has been investigated. The CCVD technique enables the decoration of CNTs on microscaled ACFs, creating a hierarchy CNT-ACF composite. The as-grown nanotubes were found to have a tortuous shape and to be several micrometers in length. The deposition of CNTs efficiently shifts the micropore size distribution of ACFs to mesoporosity. The adsorption isotherms for phenol and BV10 on ACF and CNT-ACF adsorbents are well characterized by the Dubinin-Radushkevich and Langmuir models. The surface accessibility, the equilibrium rate constant, and the adsorption energy are significantly enhanced due to the deposition of CNTs, as analyzed by these models. Accordingly, the existence of CNTs on ACF adsorbent plays a positive role in facilitating pore accessibility to adsorbate and providing more adsorptive sites for the liquid-phase adsorption.

Photocatalytic hydroxylation of benzene to phenol over titanium oxide entrapped into hydrophobically modified siliceous foam

The selective photocatalytic conversion of benzene to phenol was achieved on titania incorporated in hydrophobically modified mesocellular siliceous foam (MCF). Titanium oxide nanoparticles entrapped into mesocellular siliceous foam (TiO2@MCF) were prepared by “co-condensation” method using block copolymer as a template. TiO2@MCF was further modified by surface organo-grafting with silylation agent to make it hydrophobic (TiO2@MCF/CH3) and the grafted organic functional groups on the surface of TiO2 were selectively removed by post UV-irradiation to obtain the catalyst (TiO2@MCF/CH3/UV) that has a higher selective activity for benzene oxidation. By modifying the hydrophobicity of the mesoporous siliceous cage environment, both the adsorption of reactants (benzene) and the desorption of the desired products (phenol) on photocatalytic sites can be facilitated with an increase in selectivity and yield of phenol production. The titania nanoparticles incorporated into MCF cage were characterized by X-ray diffraction, nitrogen adsorption–desorption, high-resolution transmission electron microscopy, energy-dispersive X-ray analysis, and UV–visible diffuse reflectance spectroscopy. The hydrophobic modification of the catalysts was confirmed by Fourier transform infrared spectroscopy, water contact angle measurement, and thermo-gravimetric analysis. The adsorption isotherms of benzene and phenol on various catalysts suspended in aqueous solution were measured to investigate the effect of hydrophobic MCF cage. The hydrophobically modified TiO2@MCF/CH3/UV sample showed the highest selectivity and yield for the photocatalytic hydroxylation of benzene to phenol in aqueous solution. This could serve as an efficient and green photocatalyst for the selective oxidative conversion of a hydrophobic reactant to a hydrophilic product.

Influence of the solvation process on solute adsorption in reversed phase liquid chromatography

The adsorption isotherms of phenol were acquired by frontal analysis on six different reversed phase adsorbents from five different organic solvent solutions. The end-capped octadecyl columns only differed in the bonding density of the C 18 ligands. The inverse method was used to confirm the estimated isotherm parameters derived from the frontal experiments. The effect of the bonding density of the end-capped octadecyl bonded phase on the adsorption properties of phenol from different mobile phase compositions was investigated. The adsorption behavior of phenol has changed from Langmuir type to BET type with the change of the organic modifier and the bonding density of the adsorbent.

Adsorption and Stabilization of Phenol by Modified Local Clay

Phenol is a common pollutant that was listed by US Environmental Protection Agency (EPA) among the priority pollutants. Classical methods employed for phenol removal are either costly or limited to large-scale applications such as biological and thermal decomposition methods. In this study, adsorption of phenol by a type of clay that is extracted from a local soil called Khoweldi was investigated. The X-Ray diffraction revealed that the studied clay is mainly muscovite. The study showed that the local clay could be used as matrix for long-term storage of organic pollutants. Phenol adsorption isotherms conducted on natural and modified clay with Hexadecyltrimethylammonium (HDTMA) revealed that HDTMA enhanced the adsorption capacity of the clay for phenol.To prevent the migration of the adsorbed pollutants into the environment, encapsulation of the modified clay by organosilane was found to be very effective.

π-Selective stationary phases: (II) Adsorption behaviour of substituted aromatic compounds on n-alkyl-phenyl stationary phases

The frontal analysis method was used to measure the adsorption isotherms of phenol, 4-chlorophenol, p-cresol, 4-methoxyphenol and caffeine on a series of columns packed with home-made alkyl-phenyl bonded silica particles. These ligands consist of a phenyl ring tethered to the silica support via a carbon chain of length ranging from 0 to 4 atoms. The adsorption isotherm models that fit best to the data account for solute–solute interactions that are likely caused by π–π interactions occurring between aromatic compounds and the phenyl group of the ligand. These interactions are the dominant factor responsible for the separation of low molecular weight aromatic compounds on these phenyl-type stationary phases. The saturation capacities depend on whether the spacer of the ligands have an even or an odd number of carbon atoms, with the even alkyl chain lengths having a greater saturation capacity than the odd alkyl chain lengths. The trends in the adsorption equilibrium constant are also significantly different for the even and the odd chain length ligands.

Characterization of macroporous carbon-cryostructured particle gel, an adsorbent for small organic molecules

Preparation of a new type of cryostructured carbon particle macroporous gel with one-step sub-zero cross-linking was studied in this work. Aggregation of nano- and micro-particles of poly(N-isopropylacrylamide-co-allylamine) was used to form a polymeric network to integrate activated carbon particles. The cryostructured particle gel was compared with the conventional composite cryogel. The unique macroporous structure of the gel in combination with retained porosity of the carbon particles makes it suitable in separation and environmental applications. The adsorption isotherm of phenol was studied and the advantages of cryostructured particle gel over conventional composite structures were compared in this study. The developed new gels were characterized by scanning electron microscopy, mercury porosimetry and texture analysis.