Adsorbent For Removal Of Phenol Research Articles

Adsorptive removal of phenol from synthetic wastewater using hexadecyltrimethylammonium bromide-functionalized cellulose nanocrystal (HDTMA-Br/CNCs)

Phenol is nonetheless considered a major pollutant and, therefore should be treated to eliminate the phenol in wastewater to save the environment, people, and organisms from the negative impacts of phenol. This study, for the first time, investigates the synthesis and performance evaluation of hexadecyltrimethylammonium bromide-functionalized cellulose nanocrystals (HDTMA-Br/CNCs) adsorbent for removing phenol from synthetic phenol-containing wastewater. The CNCs were prepared from as-received cellulose, by mixed acid hydrolysis consisting of sulfuric acid, glacial acetic acid, and deionized water in a mass ratio of 1:7:2. The prepared CNCs were functionalized by adding 20 g of the produced CNCs to the HDTMA-Br solution and stirred for 120 min . The synthesized and HDTMA-Br-functionalized CNCs were characterized using different analytical techniques, such as Scanning Electron Microscopy (SEM-EDX) to examine the surface morphology and the elemental composition of the modified and unmodified adsorbents. Fourier Transform Infrared (FTIR) was used to examine the attachment of the functional group. X-ray diffraction (XRD) was used to analyze the crystalline structure of the adsorbent. To evaluate the performance of the synthesized adsorbent in batch mode, 1 g/L of phenol was used to prepare the synthetic phenol-containing wastewater. The analysis of the feed and permeate was done using pre-calibrated High-Performance Liquid Chromatography (HPLC). The multi-BET surface area of CNCs was 24.11 m2 g−1, meanwhile, fCNCs possessed a higher surface area of 201.4 m2 g−1 with a pore volume of 0.069 cm3 g−1. About ∼75 ± 1.4% phenol removal was obtained for the functionalized CNCs compared to the non-functionalized CNCs adsorbent having ∼43 ± 0.1% phenol removal at 35 °C reaction temperature. It could be observed that the spent adsorbent a shows percentage phenol removal of 70.0 ± 0.8% and 35.5 ± 1.4%, for fCNCs and CNCs at the 3rd cycle. The Langmuir and Freundlich isotherms best match the experimental data, while the pseudo-first-order kinetic model provided the greatest fit to the kinetic data. Thus far, the results suggest that modified CNCs may be an alternative adsorption material for phenol removal in wastewater.

GO-Fe3O4-CeO2-CTAB nanocomposite as a high-performance adsorbent for removal of phenol from aqueous solutions

ABSTRACT This study aimed to assess GO-Fe3O4-CeO2-CTAB nanocomposite adsorption efficiency for removing the phenol molecules from the aqua solution. The researcher performed the batch investigations to estimate the percentage of phenol removal from wastewater with the variation of pH value from 3 to 10, adsorption time from 5.000 to 100.000 min, the adsorbent dose from 0.003 to 0.040 g, the phenol concentration from 20.000 to 440.000 mg L−1 and temperature from 25 to 60°C. The GO-Fe3O4-CeO2-CTAB nanocomposite produced by a Co-precipitation method was used to adsorb and remove phenol molecules from an aqueous solution. The synthesised nano-sorbent was investigated by different methods including FTIR, XRD, SEM, EDX, VSM and BET techniques. The gained data show that the best removal efficiency of phenol by GO-Fe3O4-CeO2-CTAB nanocomposite was obtained at pH = 8, the absorbent dosage of 400.000 mg L−1 (0.020 g), contact time = 60 min and temperature of 25°C. For the equilibrium study, based on the obtained coefficients correlation of definition from fitted models, the highest value is obtained for the Langmuir model, (KL = 0.048 L mg−1, qm = 492.000 mg g−1, RL = 0.509 and R2 = 0.992), so, phenol adsorption on the surfaces of GO-Fe3O4-CeO2-CTAB nanocomposite was a monomolecular adsorbed layer. Based on obtained R2 values, it can be concluded that the pseudo-second-order kinetic model seemed to be match well with the adsorption of phenol molecules at the surface of GO-Fe3O4-CeO2-CTAB nanocomposite in three concentrations of 50.000, 100.000 and 125.000 mg L−1 (qe2 = 52.080, 103.090 and 129.870 mg g−1, k2 = 0.005, 0.003 and 0.002 g mg−1 min−1, R2 = 0.999, 0.999 and 0.999 respectively).

Combined experimental and molecular dynamics removal processes of contaminant phenol from simulated wastewater by polyethylene terephthalate microplastics

ABSTRACT Microplastics (MPs) and phenolics are pollutants found ubiquitously in freshwater systems. MPs oftentimes serve as a vector for pollutants across ecosystems and are now being explored as alternative adsorbents for pollutant removal. This strategy would reflect the ‘reuse’ of an existing waste stream into a potentially useful product while at the same time helping to minimize plastic waste in the marine environment. In this study, the adsorption of phenol onto pristine (Pr-PET), modified (Mod-PET), and aged (Ag-PET) Polyethylene Terephthalate (PET) microplastics was examined experimentally and theoretically. Kinetics, isotherms, and thermodynamics models were used to investigate the adsorption process while Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were employed to investigate molecular level alterations. The result showed that the Ag-PET MPs had the best removal efficiency due larger surface area and the adsorption occurred in a pseudo-second-order manner, showing that the rate of phenol adsorption is directly proportional to the number of surface-active sites on the surface of PET MPs while the intraparticle diffusion defined rate-limiting step. However, the maximum monolayer adsorption capacity followed Mod-PET (38.02 mg/g) > Ag-PET (8.08 mg/g) > Pr-PET (6.84 mg/g). The adsorption process proceeded spontaneously and thermodynamically favourable. GCMC-MD simulations revealed that PET MPs are capable of successfully adsorbing the phenol molecule through Van der Waals and electrostatic interactions and can be adopted as novel adsorbents for phenol removal in aqueous solutions.

High‐Efficiency Adsorptive Removal of Phenol from Aqueous Solution Using Natural Red Clay and ZnO Nanoparticles

AbstractPhenol, a highly toxic compound, is a common hazardous chemical. Hence, eco‐friendly and cost‐effective technology for phenol elimination is required. The present study presents a comprehensive study to eliminate phenol compounds via an adsorption technique using ZnO nanoparticles and natural red clay as adsorbents. X‐ray diffraction (XRD), X‐ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and Burnauer‐Emmett‐Teller (BET) analyses were conducted for adsorbent surfaces characterization. The impacts of various effects, such as pH and the adsorbent dose on the phenol removal efficiency are described. The results reveal that both ZnO and clay adsorbents removed 99.4 % of phenol at the optimum adsorbent dose of 0.6 g\L and 1 g\L with pH 8 and 2, respectively. The isotherm adsorption data for phenol fitted into Langmuir for the two adsorbents. Yet, the ZnO nanoparticle surface showed a higher capacity (342.72 mg\g) than the natural clay surface (84.01 mg\g). ZnO nanoparticles removed phenol from polluted water at a smaller dose (0.6 g\L) than natural clay (1 g\L). In conclusion, the two adsorbents showed high efficiency in the phenol compound removal.

Removal of phenol from aqueous solution using reduced graphene oxide as adsorbent: isotherm, kinetic, and thermodynamic studies.

This work focuses on the batch adsorption study of phenol from an aqueous solution. Here, reduced graphene oxide (RGO) is used as an adsorbent. To synthesize reduced graphene oxide from graphene oxide, hydrazine monohydrate is used as a reducing agent. The synthesized samples were characterized using SEM, EDX, XRD, FTIR, BET surface area analyzer, RAMAN spectra, and zeta potential. The effects of solution pH, adsorption time, temperature, adsorbent dosage, and initial phenol concentration on adsorption characteristics were systematically studied. The optimized adsorption parameters were 0.4g/L of adsorbent dosage, pH of 8.0, adsorption time 75min, and temperature of 30°C. The adsorption isotherm data follows the Langmuir isotherm model, and the maximum adsorption capacity (qm) was 602.41mg/g. The kinetic data of the adsorption follows the pseudo-second-order kinetic model. The Boyd model confirmed that film diffusion was the rate-limiting step in the adsorption process. The thermodynamic study of phenol adsorption using RGO confirms the endothermic nature of the process. The negative values of Gibb's free energy (ΔGo) confirm that the process was spontaneous. The positive value of change in entropy (ΔSo = 346.885J/K) suggests that the randomness was increased at the solution/solid interface. The most important feature of this adsorbent was it could be easily and efficiently regenerated from phenol-loaded adsorbent with a negligible effect on removal efficiency. This study evidenced an effective use of RGO as an adsorbent for phenol removal.

Prediction of chlorophenols adsorption on activated carbons by representative pores method.

The specification of a particular activated carbon adsorbents for removal of phenol and related derivatives, from dilute aqueous solutions, is still based on lengthy trial and error experimental tests. A predictive model of adsorption of these compounds would considerably reduce the carbon selection time and could also bring new information to support more efficient carbon synthesis. The use of molecular simulation and the methodology of representative pores proved to be adequate for quantitative prediction of phenol adsorption. Here the methodology is being extended to chlorophenols, an important class of phenol-derived pollutants. A set of ortho- and para-chlorophenol isotherms were simulated for different representative pores in order to predict carbon adsorption and determine the most significative pore size. At low concentrations (1 × 10-4mol/L), the pores of 8.9 and 18.5Å are the most effective. For concentrations above 3 × 10-4mol/L, pores in the range of 27.9Å must be present in the activated carbon. The simulation predicts a step for the 27.9Å pore that can be correlated with experimental steps in literature. Finally, the adsorption isotherms of chlorophenols for other activated carbons were predicted with the help of the model.

Adsorptive removal of phenol from aqueous solution using chemically modified Saccharum officinarum biomass: modelling and process optimisation

ABSTRACT This article proposes a way to extract phenol from aqueous solution as synthetic wastewater through the biomass (saccharum officinarum)-derived ZnCl2-activated carbon named as SBAC. The surface area and pore radius of SBAC were found to be 415.960 m2/g and 0.725 nm, respectively. Batch adsorption studies were carried out to analyse the percentage removal of phenol under various conditions, such as initial concentration (50–500 mg/L), initial pH (2–12), adsorbent dosage (2–40 g/L), temperature (283–303 K) and contact time (30–360 min). The proposed study has achieved ~94% of maximum phenol extraction, with the adsorption capacity of 9.44 mg/g at an initial concentration of 50 mg/L, dose of 5 g/L, pH of 5.5, contact time of 60 min and temperature of 303 K. The kinetic and equilibrium studies confirmed pseudo-second-order reaction and Radke-Prausnitz isotherm as the best fit. In thermodynamic study, the negative values of ΔG0 ads (−21.448 to −24.330 kJ/mol), ΔH0 (−1.059 kJ/mol) and positive value of ΔS0 (0.072 kJ/mol K) confirmed the spontaneity, exothermic nature and randomness of adsorption process, respectively. Regeneration and reusability of SBAC showed 86.45% removal of phenol till fifth consecutive cycles. Cost analysis revealed that the developed SBAC was 14 times less expensive (~718 INR/ 9 $) than commercial activated carbon. From the present study, the developed adsorbent found to be good for wastewater treatment under ambient reaction conditions to achieve clean water.

Synthesis of Succinylated Starches and Their Application as Adsorbents for the Removal of Phenol

Succinylated starches (SS) were prepared by the reaction of normal starch (NS) and porous starch (PS) with succinic anhydride (SA) in the presence of DMF solvent and base pyridine, respectively. The proton nuclear magnetic resonance and Fourier transform infrared were used to confirm the successful synthesis of the SS (SS1, SS2, SS3 and SS4, respectively). The X-ray diffractometer XPert PRO (Cu Kα, λ = 1.54 A) was used to study the crystallinity of NS, PS and SS. The XRD analysis showed that the SS exhibited amorphous nature after succinylation. Thermogravimetric analysis and differential thermal analysis of NS, PS and SS showed that succinylation decreased the thermal stability. The morphology of the NS, PS and SS was studied by SEM. These SS were used as adsorbents for phenol removal. The adsorption efficiencies for phenol by NS, SS1, SS2, SS3 and SS4 were found to be 0.084 g/g, 0.165 g/g, 0.173 g/g, 0.183 g/g and 0.189 g/g, respectively.

Eco friendly adsorbents for removal of phenol from aqueous solution employing nanoparticle zero-valent iron synthesized from modified green tea bio-waste and supported on silty clay

The present research investigated a novel route for the synthesis of nanoparticle zero-valent iron (NZVI) utilizing an aqueous extract of green tea waste as a reductant with ferric chloride. Also, the supported nanoparticle zero-valent iron was synthesized using natural silty clay as a support material (SC-NZVI). The NZVI and SC-NZVI were characterized by infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and zeta potential ( ζ ). The interpretation of the results demonstrated that the polyphenol and other antioxidants in green tea waste can be used as reduction and capping agents in NZVI synthesis, with silty clay an adequate support. Additionally, the experiments were carried out to explore phenol adsorption by NZVI and SC-NZVI. To determine the optimum conditions, the impact of diverse experimental factors ( i.e. , initial pH, adsorbent dose, temperature, and concentration of phenol) was studied. Langmuir, Freundlich, and Tempkin isotherms were used as representatives of adsorption equilibrium. The obtained results indicated that the adsorption processes for both NZVI and SC-NZVI well fitted by the Freundlich isotherm model. The appropriateness of pseudo_first_order and pseudo_second_order kinetics was investigated. The experimental kinetics data were good explained by the second-order model. The thermodynamic parameters (Δ H 0 , Δ S 0 , and Δ G 0 ) for NZVI and SC-NZVI were determined. The maximum removal rates of phenol at optimum conditions, when adsorbed onto NZVI and SC-NZVI, were found to be 94.8% and 90.1%, respectively.

Adsorptive removal of phenol from wastewater using guava tree bark.

The phenol removal by adsorption through the guava tree bark has been studied in this research. The surface characterizations of the guava tree bark were assessed through BET, FTIR, and SEM apparatus. The phenol removal percentage was investigated in batch experiments taking phenol content (30-150mg/L), time (30-180min), pH (4-9), adsorbent dose (1-6g/L), and temperature (30-50°C). The maximum percentage of phenol removal was obtained at 90.67% at the phenol concentration of 30mg/L, the contact time of 120min, pH of 7, adsorbent dose of 4g/L, and temperature of 50°C. The kinetic study indicated that the second-order was superior to the first order. The isotherm study exhibited that the Freundlich isotherm fitted best among the Langmuir, D-R (Dubinin-Radushkevich), and Temkin isotherms. The value of adsorption energy evaluated by the D-R isotherm supported physical adsorption; however, the mechanism seemed to be weaker since the correlation coefficient of the D-R model was found to be quite less than the correlation coefficients of other isotherm models. The adsorption mechanisms through film diffusion and chemisorption were well established as tested by the Reichenberg model, the Elovich model, the Fick model, the Furusawa and Smith model, and the Boyd model. The adsorption thermodynamics concluded that the adsorption method supported endothermic, random, and spontaneous. The scale-up design, the procedure for safe disposal of spent adsorbent, and the regeneration of the adsorbent were deliberated in this research. The research determined that the guava tree bark is suitable for the removal of phenol from wastewater.

Synthesis of carbon nanotubes grafted with PEG and its efficiency for the removal of phenol from industrial wastewater

Carbon nanostructures have a great potential in various applications. They are considered as promising sorbents of contaminants owing to their unique physical and chemical behaviors. In this work, a hybrid adsorbent was successfully prepared by oxidizing carbon nanotube (CNT) and grafted with polyethylene glycol (PEG). The performance of the hybrid material (CNT/PEG) as an adsorbent was investigated for the phenol removal in a batch system. The effects of contact time, initial solution pH, the initial concentration of phenol, and adsorbent dosage on the efficiency of phenol removal were investigated. The phenol adsorption by CNT/PEG was pH-dependent and under optimum conditions, high adsorption efficiency (≈100 %) was achieved at a contact time of 30 min. The magnitude of R2 acquired with the pseudo-second-order model is high (>0.99) which indicates the process follows this model. Both the Langmuir and Freundlich isotherm models show a good fit to the adsorption experimental data. However, Freundlich model shows a better fit to the experimental results than the Langmuir model (R2 > 0.98). The prepared hybrid material (CNT/PEG) demonstrated to be an efficient adsorbent for removal of phenol from water as well as for simultaneous removal of phenol with pollutants such as Cu, Hg, Cr, Fe, Co, Ni, Al and Pb from industrial wastewater.

Adsorptive removal of phenol using faujasite-type Y zeolite: Adsorption isotherms, kinetics and grand canonical Monte Carlo simulation studies

Phenol and its derivatives are hazardous pollutants commonly found in industrial wastewaters. Their removal is a high priority for avoiding adverse impacts on the environment. Herein, the removal of phenol from wastewater, used as a model organic contaminant, onto faujasite-type Y zeolite (NaY) was investigated using experimental and theoretical techniques. The surface morphology was studied by scanning electron microscope (SEM). Mineralogical information and the crystal structure of zeolite were determined by X-ray diffraction (XRD). Surface area measurements were obtained by employing the nitrogen adsorption method. The phenol adsorption at different adsorption temperatures and pH was studied through batch experiments. The isotherm analysis results showed that the Langmuir adsorption isotherm model was the most suitable to describe the adsorption of phenol on zeolite NaY. The results indicated that the adsorption kinetic data were followed more closely the Pseudo-second order and intra-particle diffusion models. Grand Canonical Monte Carlo (GCMC) simulations were used to simulate the adsorption isotherm of the phenol in the zeolite at different temperatures. From the simulation study, density distribution profiles, the isosteric heat of adsorption and the sorption energy distribution were investigated. The results are very promising and point to the need for further investigation.

Adsorption of Phenol from Wastewater Using Modified Layered Double Hydroxide Clay

Phenol and its derivatives are some of the organic pollutants found in wastewater and they pose health risks to human beings and animals if left untreated. This work investigates the use of modified Layered Double Hydroxide clay as an adsorbent for removal of phenol from wastewater. High exchange capacities, capability to be modified with surfactants and through calcination, and the ability to regenerate are some of the properties of the clay reported in literature which make it an ideal adsorbent for phenol removal from wastewater. Modification of neat clay with silane increased the adsorption percentage from 6 % to 19 %, however the extent of adsorption was reduced from 87 % to 35 % when calcined clay was coated with a silane material. Calcination of the clay increased its BET surface area from 8.71 m2/g to 29.74 m2/g. The adsorption kinetics were best fitted by the pseudo second order model. The equilibrium isotherms which best fitted the adsorption data were the Freundlich isotherm and the Three Parameter Langmuir-Freundlich isotherm. The maximum adsorption capacity of 59.1 mg/g was observed using the Three Parameter Langmuir-Freundlich isotherm.

Adsorptive removal of phenol using banyan root activated carbon

Adsorption is an easy and efficient technique for phenolic wastewater treatment. The present study highlights the preparation, characterization and application of activated carbon obtained from the banyan tree’s aerial root waste for phenol removal studies. The banyan root activated carbon (BRAC) was chemically modified using potassium hydroxide (KOH) as the activation agent. Various characterization studies revealed the highly porous structure of BRAC with a considerable amount of functional groups present on its surface. Surface area analysis showed a specific surface area of 988 m2/g (BET method) and average pore radius of 24 nm (BJH method). Studies on the relationship between adsorption parameters and adsorption performance indicated that the BRAC possessed a maximum phenol removal efficiency of 89.2% for the optimized values of the adsorption parameters. Thermodynamic investigations showed that the adsorption process was spontaneous and exothermic in nature. Further, the phenol adsorption on BRAC conformed to Langmuir model with a theoretical maximum adsorption capacity of 26.95 mg/g. Kinetic analysis revealed that the phenol adsorption on BRAC followed pseudo-second order model. Reusability studies revealed that BRAC can be reused for a maximum of three cycles for continual phenol adsorption from its aqueous streams. Thus, banyan root waste assures to be a potential and economical biomass for production of activated carbon towards the adsorptive treatment of phenol contaminated wastewater streams.

Preparation of activated carbon from black wattle bark waste and its application for phenol adsorption

Black wattle bark waste is generated in large amounts by tannin extraction industries, which leads to an environmental problem. In literature there are few reports about reusing this waste, mainly in adsorption processes. An activated carbon from black wattle bark waste was produced, characterized and applied for phenol adsorption. Activated carbon was produced under different carbonization and activation conditions, being characterized and applied as an adsorbent for phenol removal from aqueous solution. The results showed that phenol adsorption capacity increased with the increase of carbonization temperature and of activating agent ratio and, decreased with the increase of carbonization time. Activated carbon presented a micro/mesoporous structure and the surface area was 414.97 m2 g−1. FTIR analysis showed that lactone and quinone groups compose the surface chemistry of the activated carbon. The adsorption kinetics followed the pseudo-second order model. The Weber-Morris model showed that the adsorption occurred by film and intra-particle diffusion, and the increase in stirring rate led to an increase in film diffusion. Temperature increase led to an increase in phenol adsorption capacity, and the highest value was around 98.57 mg g−1, obtained at 55 °C. The Freundlich isotherm model was the more suitable to represent the equilibrium data. Thermodynamic study indicated that phenol adsorption onto the developed activated carbon was a spontaneous, favorable, endothermic and entropy-controlled process. The activated carbon can be used in two cycles with a slight decrease in the equilibrium adsorption capacity and presented a good efficiency to remove phenolic compounds in a simulated industrial effluent.

Adsorptive Removal of Phenol by Activated Alumina and Activated Carbon from Coconut Coir and Rice Husk Ash

Phenol (C6H5OH) is considered as a serious environmental pollutant, and therefore, the study for its removal from wastewater by adsorption has gained momentum by many researchers. The purpose of this research was to study the phenol removal efficiency using three adsorbents viz. activated alumina and activated carbon from coconut coir and rice husk ash. Initially, the characterizations of the adsorbents were performed. The phenol removal percentage was then investigated in batch experiments with the change of process variables, e.g., initial phenol concentration, contact time, pH, temperature, and adsorbent dose. The experimental results showed that at optimum conditions, the maximum phenol removals for activated alumina and activated carbon from coconut coir and rice husk ash were 21.8%, 95.2%, and 94.23% respectively. These results were tested using several isotherms and kinetic and thermodynamic models. The test of kinetic models showed that pseudo-second-order model was fitted better than the pseudo-first-order model for all three adsorbents. The test of isotherm models showed that the Freundlich isotherm was better for activated alumina and activated carbon from coconut coir, whereas the Langmuir isotherm was better for rice husk ash. The thermodynamic study showed that the adsorption process was non-spontaneous, non-random, and exothermic for activated alumina; spontaneous, non-random, and exothermic for activated carbon from coconut coir; and spontaneous, random, and endothermic for rice husk ash. The safe disposals of the spent adsorbents were also deliberated in this study. The research discovered that the preference of adsorbents for phenol removal was rice husk ash, activated carbon from coconut coir, and activated alumina. The novelty of this study was that the paper had included exhaustive analysis using testing of numerous models viz. pseudo-first-order model, pseudo-second-order model, Reichenberg model, Fick model, Furusawa and Smith model, Elovich model, Boyd model, Langmuir model, Freundlich model, Temkin model, and Dubinin–Radushkevich model.

Removal of phenol and phosphate from aqueous solutions using activated carbons prepared from oily sludge through physical and chemical activation.

Preparation and characterization of activated carbons (ACs) from oily sludge by physical and chemical activation using steam, ZnCl2 and FeCl3 were investigated. The characteristics of produced adsorbents were determined by iodine number, Brunauer-Emmett-Teller (BET) equation, Fourier transform infrared spectrometry and scanning electron microscopy analyses. Batch adsorption experiments for phenol and phosphate were performed to evaluate the efficiency of adsorbents. The optimum porous structure of adsorbents with a BET surface area of 1,259 m2 g-1, total pore volume of 1.22 cm3 g-1 and iodine number of 994 mg g-1 was achieved by ZnCl2 activation at 500 °C and impregnation ratio of 1:1. The adsorption data were well fitted to the pseudo-second-order kinetic model (R2>0.99) and Freundlich isotherm (R2>0.99). The maximum adsorption capacity of phenol (238 mg g-1) and phosphate (102 mg g-1) based on the Langmuir model was achieved at pH of 6.0 and adsorbent dose of 1 g L-1. Thermodynamic parameters were negative and showed that adsorption of phenol and phosphate onto the AC was feasible, spontaneous and exothermic. The results suggested that prepared AC was an effective adsorbent for removal of phenol and phosphate ions from the polluted water.

Magnetic porous polymer microspheres: Synthesis, characterization and adsorption performance for the removal of phenol

The magnetic poly(ethylene glycol dimethacrylate-n-vinylimidazole) (Fe3O4@poly (EGDMA@VIM)) microspheres were prepared by suspension polymerization method using magnetite Fe3O4 nano-powder and the porosity, morphology, chemical composition and structure of the magnetic polymer microspheres were characterized. The specific surface area and swelling ratio of the Fe3O4@poly(EGDMA@VIM) microspheres were found to be 278.6 m2·g–1 and 48%, respectively. The Fe3O4@poly(EGDMA@VIM) microspheres were used as an adsorbent for phenol removal. The effects of the parameters such as adsorbent dosage, temperature, pH and initial concentration of phenol solutions on the adsorption were investigated. The experimental adsorption equilibrium data obtained were fitted with Langmuir, Freundlich and Dubinin-Radushkevich isotherms and the pseudo-first-order, pseudo-second-order and intra–particle diffusion kinetic models. The adsorption equilibrium data agreed well with the Freundlich isotherm and the pseudo-second-order kinetic model. The maximum capacity of the Fe3O4@poly(EGDMA@VIM) microspheres was calculated to be 33.83 mg·g–1 at 298 K and natural pH from Langmuir isotherm. The Fe3O4@poly(EGDMA@VIM) microspheres were found to be reusable for removal of phenol after desorption for several times. The result indicated that the Fe3O4@poly(EGDMA@VIM) microspheres are potential candidate for removal of phenol in wastewaters.

Carbon gel monoliths with introduced straight microchannels for phenol adsorption

Adsorption of phenol using carbon adsorbents in the form of a packed bed of particles inherently suffers from the incompatibility between low hydraulic resistance and short diffusion path length. In this work, carbon gel monoliths made from resorcinol–formaldehyde gels with introduced straight microchannels in the range of 60–160 µm were successfully synthesized using polyesters fibers as templates. The advantage of this synthesis method is that both channel size and channel density can be tuned independently. Introduced microchannels were effective in minimizing the pressure drop of a fluid flowing through the sample to less than a hundredth of beds packed with particles having the same diffusion path length. Synthesized monoliths also possess sufficient mechanical strength (more than 12 kg per monolith) to be activated to increase their adsorption capacity. Adsorption experiments of phenol in a continuous flow system show that synthesized monoliths can be used as effective adsorbents for phenol removal. The tunable channel size and channel density of the proposed synthesis method has the potential for the synthesis of monoliths which could be used to fulfill various process demands.

Adsorptive removal of phenol from aqueous solutions using chemically activated rice husk ash: equilibrium, kinetic, and thermodynamic studies

Adsorptive removal of phenol from aqueous solutions using chemically activated rice husk ash: equilibrium, kinetic, and thermodynamic studies