Methyl Tert-butyl Ether Adsorption Research Articles

Structural modification of graphene material by silicon mono-doping and codoping with heteroatoms as sensors for methyl tert-butyl ether (MTBE) as a fuel additive: Insights from DFT

Due to the association of methyl tert-butyl ether (MTBE) with groundwater contamination and environmental concerns, fuel additives, and recognized health hazards, including respiratory and central nervous system effects upon exposure, the implementation of mitigating measures becomes imperative on a global scale, particularly through the utilization of nano-oriented materials. Hence, to account for the sensitivity, detection, and adsorption of methyl tert-butyl ether (MTBE) pollutants, this research attempts to investigate the potential of silicon-doped graphene (Si@GP) engineered with boron, nitrogen, and phosphorous atoms by employing density functional groups at the ωB97XD/def2vsp level of theory. Interestingly, the results from several quantum descriptors were analysed to obtain comprehensive knowledge of the interactions between the adsorption complexes. The examined systems (MTBE-Si@GP, MTBE-SiB-GP, MTBE-SiN-GP, and MTBE-SiP-GP) produced Fermi energies of 0.4531 eV, 0.4531 eV, 0.5274 eV, and 0.3936 eV, respectively, providing valuable insights into their electronic structure and sensitivity to MTBE. Subsequent calculations revealed that MTBE-SiP-GP had a work function of 0.3936 eV, making it a superior surface for sensing MTBE compared to the other surfaces considered. The adsorption energies for MTBE-Si@GP, MTBE-SiB-GP, MTBE-SiN-GP, and MTBE-SiP-GP were 8.004 eV, 7.159 eV, 7.785 eV, and 5.027 eV, respectively. Despite their physisorption properties, MTBE-SiP-GP was highlighted as the preferable absorbent at the BSSE level. The comprehensive analysis presented in this study highlights the potential of the MTBE-SiP-GP dopant as a reliable sensing material for monitoring MTBE liquified gas in real-world environments. Our research aims to equip experimental researchers with valuable insights on the silver graphene dopant, and specifically, the MTBE-SiP-GP surface, as a promising candidate for detecting gas sensors.

Effective and selective adsorption of methyl tert-butyl ether on ZSM-5 zeolite: a comparative study.

The extensive use of methyl tert-butyl ether (MTBE) as a gasoline additive has caused serious environmental problems that need to be addressed urgently. The feasibility of remediation of MTBE-contaminated groundwater by ZSM-5 zeolite with SiO2/Al2O3 ratio of 50/130/360 was explored. The SiO2/Al2O3 ratio had a great influence on the physicochemical properties and structure, as well as the adsorption and mass transfer of MTBE on ZSM-5. The adsorption of MTBE on zeolites with SiO2/Al2O3 ratios of 50 and 130/360 followed the Langmuir and Freundlich models, respectively, and was controlled by different mass transfer processes. The morphology and adsorption capacity of ZSM-5 (50) and ZSM-5 (130) differed significantly, while the differences between ZSM5-(130) and ZSM-5 (360) were less pronounced. ZSM-5 (360) had higher adsorption capacity and adsorption efficiency for MTBE, and the larger BET surface area, pore volume and stronger hydrophobicity were the key factors to promote MTBE adsorption. Compared to activated carbon (AC), ZSM-5 (360) was more effective for MTBE removal at low concentrations (≤200mg·L-1) and had the advantage of selective adsorption of MTBE with the addition of BTEX. In column adsorption, decreasing the concentration had opposite effects on MTBE removal by ZSM-5 and AC. At 5-10mg·L-1, ZSM-5 (360) column reduced effluent concentration and improved bed utilization and removal efficiency.

Mesoporous magnesia sorbent for removal of organic contaminant methyl tert -butyl ether (MTBE) from water

ABSTRACT Methyl tertiary butyl ether (MTBE) is used as a gasoline additive formed by the reaction of isobutylene and methanol. Due to its high water solubility and low soil adsorption coefficient, leakages from storage facilities cause immediate groundwater contamination. The aim is to use alternative adsorbent for the removal of MTBE that causes various environmental and health problems. Mesoporous magnesia (MgO) that was synthesized via template-free hydrothermal method and commercial adsorbent Sepabeads-207 (SP-207) were used in this study. MTBE adsorption experiments were carried out at room temperature with a fixed sorbent/liquid ratio (0.1 g sorbent/10 mL aqueous solution) and 100–500 mg/L MTBE initial concentrations. Batch adsorption experiments showed that MgO and SP-207 have high MTBE adsorption capacity with a maximum adsorption amount of 333 and 233 mg MTBE/g adsorbent. Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models of adsorption isotherms were used to investigate the adsorption behavior and the Langmuir isotherm model showed a better fit. Adsorption kinetic studies were also performed, and the pseudo-second-order kinetics fitted well with experimental data. Gibbs free energy changes of adsorption were obtained as −48.4 and −60.3 kJ/mol for MgO and SP-207, respectively. Methanol was used to regenerate the used adsorbents, and the re-use of MgO demonstrated good performance.

Batch adsorption of methyl tert-butyl ether (MTBE) from aqueous solution by combined CNT and zeolite

Batch adsorption of methyl tert-butyl ether (MTBE) from aqueous solution by combined CNT and zeolite

Cellulose-Nanofiber-Mediated Sorption-Benefitting Holed Silicalite-1 Crystals.

Silicalite-1-type zeolites with unique intracrystal holes or cracks were successfully prepared using a cellulose nanofiber (CNF) as an additional mediating material, and their vapor phase adsorption properties toward methyl tert-butyl ether (MTBE) and n-nitrosodimethylamine (NDMA) were examined. It was found that the mixing protocol of CNF and structure-directing agents (SDAs), the addition amount of CNF, and the CNF/SDAs amount ratio play important roles in forming the holed silicalite-1. The synthesis route that preliminarily mixes CNF with SDAs in a series of controlled conditions is particularly beneficial for the formation of the holed silicalite-1 with mesoporosity and larger pores because the CNF-SDAs composite structure benefits the zeolite growth closely encompassing CNF inside the crystal structure. It also promotes the preferential formation of the orthorhombic phase vicinal to the CNF surface, namely, the surface of the formed internal holes or cracks, with the twin-type crystal size reduced as compared to the non-CNF-templated sample. On the contrary, the synthesis route that mixes CNF with SDAs–silicate composite ions tends to modify the twin-type crystal shape at the same time to form small but uniform well-crystallized particles with less holes or cracks and a dominative monoclinic phase. It was considered that both the inter-subunit structural defect and silanol defect whose content is increased with CNF addition influence the adsorptivity of MTBE and NDMA. Owing to the small twin-type crystal size, the smaller crystal subunits, and the favored short path from the surface of internal holes or cracks, the holed silicalite-1 derived from the CNF and SDA premixture assures the easiest access of adsorbate molecules to the most energetically favored sites and is most appropriate for the adsorption of both MTBE and NDMA among the examined zeolites.

Adsorption of methyl tert-butyl ether (MTBE) onto ZSM-5 zeolite: Fixed-bed column tests, breakthrough curve modelling and regeneration

ZSM-5, as a hydrophobic zeolite, has a good adsorption capacity for methyl tert-butyl ether (MTBE) in batch adsorption studies. This study explores the applicability of ZSM-5 as a reactive material in permeable reactive barriers (PRBs) to decontaminate the MTBE-containing groundwater. A series of laboratory scale fixed-bed column tests were carried out to determine the breakthrough curves and evaluate the adsorption performance of ZSM-5 towards MTBE under different operational conditions, including bed length, flow rate, initial MTBE concentration and ZSM-5 dosage, and regeneration tests were carried out at 80, 150 and 300 °C for 24 h. Dose-Response model was found to best describe the breakthrough curves. MTBE was effectively removed by the fixed-bed column packed with a ZSM-5/sand mixture with an adsorption capacity of 31.85 mg g−1 at 6 cm bed length, 1 mL min−1 flow rate, 300 mg L−1 initial MTBE concentration and 5% ZSM-5 dosage. The maximum adsorption capacity increased with the increase of bed length and the decrease of flow rate and MTBE concentration. The estimated kinetic parameters can be used to predict the dynamic behaviour of column systems. In addition, regeneration study shows that the adsorption capacity of ZSM-5 remains satisfactory (>85%) after up to four regeneration cycles.

Water remediation contaminated with MTBE using a catalytic oxidation process in batch reactor: influence of the cerium loading on the activity and CO2 selectivity.

Destruction of methyl tert-butyl ether (MTBE) in liquid phase and in a batch reactor was studied using ruthenium catalysts over alumina support, modified with different cerium loadings. Ce loading increment causes an increase in the particle size from 1.26 nm to 2.3 nm, enhancing the MTBE oxidation (at 150 °C), and the selectivity toward CO2. The high catalytic activity of Ru/ACe10 is attributed to the species Ce4+-O2--M that could favor the oxygen transfer between the catalyst surface and the adsorbed species by a redox mechanism. Thus, CeOx plays an important role in both enhancing the affinity between MTBE and catalyst during MTBE adsorption and promoting the catalytic activity for MTBE oxidation.

Kinetic and equilibrium modelling of MTBE (methyl tert-butyl ether) adsorption on ZSM-5 zeolite: Batch and column studies

The intensive use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in serious environmental problems due to its high solubility, volatility and recalcitrance. The feasibility of permeable reactive barriers (PRBs) with ZSM-5 type zeolite as a reactive medium was explored for MTBE contaminated groundwater remediation. Batch adsorption studies showed that the MTBE adsorption onto ZSM-5 follows the Langmuir model and obeys the pseudo-second-order model with an adsorption capacity of 53.55 mg g−1. The adsorption process reached equilibrium within 24 h, and MTBE was barely desorbed with initial MTBE concentration of 300 mg L−1. The mass transfer process is found to be primarily controlled by pore diffusion for MTBE concentrations from 100 to 600 mg L−1. pH has little effect on the maximum adsorption capacity in the pH range of 2–10, while the presence of nickel reduces the capacity with Ni concentrations of 2.5–25 mg L−1. In fixed-bed column tests, the Dose-Response model fits the breakthrough curve well, showing a saturation time of ∼320 min and a removal capacity of ∼18.71 mg g−1 under the conditions of this study. Therefore, ZSM-5 is an extremely effective adsorbent for MTBE removal and has a huge potential to be used as a reactive medium in PRBs.

Removal of methyl tert-butyl ether (MTBE) from aqueous medium in the presence of nano-perfluorooctyl alumina (PFOAL): Experimental study of adsorption and catalytic ozonation processes

Abstract In this study, two types of nano- perfluorooctyl alumina (PFOALG and PFOALB) powders were synthesized using Wieserman and ultrasound assisted methods. XRD, SEM, BET, FT-IR and CHNOS analyses were used to characterize the nano-PFOALs. The performances of these samples were investigated for removal of MTBE from aqueous solutions using adsorption and catalytic ozonation processes. Four different adsorption isotherms, namely, Freundlich, Langmuir, BET multilayer adsorption and Temkin adsorption isotherms were used to modeling the adsorption equilibrium. The results showed that the equilibrium data of MTBE adsorption on nano-PFOALG adsorbent were well described by the BET isotherm model. The kinetics of MTBE adsorption on nano-PFOALG is best described by pseudo-second order model. Finally, the catalytic ability of nano-PFOALs was investigated for catalytic ozonation of MTBE. The removal percentage of MTBE by nano-PFOALs/O3 systems was about two times higher than ozonation alone after 90 min. Results showed that nano-PFOALs have high efficiency in catalytic ozonation of MTBE and suggested as suitable catalyst for contaminants removal in water using catalytic ozonation process.

Organoclay-based nanoparticles from montmorillonite and natural clay deposits: Synthesis, characteristics, and application for MTBE removal

This study introduces organoclay-based submicron- and nanosized particles prepared from montmorillonite (SWy2) and naturally occurring clay deposits using sequential steps of wet ball milling, ultrasonication and sedimentation followed by an ion exchange process using two surfactants, long alkyl chain HDTMA+ (hexadecyltrimethylammonium bromide) and short alkyl chain TMA+ (tetramethylammonium bromide). The resultant organoclay-based nanoparticles were characterized using X-ray diffraction (XRD), thermogravimetric-differential thermal analysis (TG-DTA) and Fourier-transform infrared (FTIR) spectroscopy. The adsorption of MTBE (methyl tert-butyl ether) by organo-montmorillonite with different surfactant loadings (0.5–2.0 CEC) in aqueous solution was also investigated. The results of XRD analysis for organoclay-based nanoparticles showed that the value of d (001) increased with increasing alkyl chain length and surfactant loading. FTIR results showed that the functional groups of the organoclays changed due to the intercalation of the long alkyl chain surfactant HDTMA+ between clay layers. The removal of MTBE is highly dependent upon surfactant type and loading. The results indicated that the organo-montmorillonite-based nanoparticles prepared from HDTMA+ have a higher affinity for MTBE in aqueous solution than the organo-montmorillonite prepared from TMA+. Therefore, long alkyl chain HDTMA+ can be considered to be the most suitable organo-modifier for enhancing the adsorption characteristics of montmorillonite for MTBE removal.

The role of mesopores in MTBE removal with granular activated carbon

This activated carbon research appraised how pore size and empty-bed contact time influenced the removal of methyl tert-butyl ether (MTBE) at part-per-billion (ppb) concentrations when MTBE was the sole organic impurity. The study compared six granular activated carbons (GACs) from three parent sources; these GACs contained a range of pore volume distributions and had uniform slurry pHs of 9.7–10.4 (i.e. the carbons' bulk surface chemistries were basic). Several of these activated carbons had been specifically tailored for enhanced sorption of trace organic compounds. In these tests, MTBE was spiked into deionized-distilled water (∼pH 7); MTBE loading was measured by isotherms and by rapid small-scale column tests (RSSCTs) that simulated full-scale empty-bed contact times of 7, 14, and 28 min. The results showed that both ultra-fine micropores and small-diameter mesopores were important for MTBE adsorption. Specifically, full MTBE loading during RSSCTs bore a strong correlation (R2 = 0.94) to the product (mL/g × mL/g) of pore volume ≤4.06 Å wide and pore volume between ∼22 Å and ∼59 Å wide. This correlation was greater than for the product of any other pore volume combinations. Also, this product exhibited a stronger correlation than for just one or the other of these two pore ranges. This multiplicative relationship implied that both of these pore sizes were important for the optimum GAC performance of these six carbons (i.e. favorable mass transfer coupled with favorable sorption).The authors also compared MTBE mass loading during RSSCTs (μg MTBE/g GAC) to isotherm capacity (μg MTBE/g GAC). This RSSCT loading “efficiency” ranged from 28% to 96% for the six GACs; this efficiency correlated most strongly to pores that were 14–200 Å wide (R2 = 0.94). This correlation indicated that only those carbons with a sufficient volume of 14–200 Å pores could adsorb MTBE to the extent that would be predicted from isotherm data.

Kinetic and equilibrium modeling of single and binary adsorption of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) onto nano-perfluorooctyl alumina

Wide spread use of methyl tert-butyl ether (MTBE) has led to pollution of drinking water sources and has received great attention. In this study, single-component and binary competitive adsorptions of MTBE and tert-butyl alcohol (TBA) onto two novel adsorbents, i.e., nano-perfluorooctyl alumina prepared by using nano-γ-alumina (nano-PFOALG) and nano-boehemite (nano-PFOALB) as the supports were investigated. In single-component experiments, experimental data were modeled with five isotherm equations (Langmuir, Freundlich, modified BET for liquid phase, Sips and Dubinin–Radushkevich). Results revealed that the adsorption isotherms of both components on two adsorbents were best described by the modified BET isotherm. The multicomponent data were fitted to seven different predictive models, especially an extended form of modified BET, has been used in the present work. For the binary adsorption system, it is found that the quality of respective single-component isotherms for each component has significant effect onto the predicting multicomponent adsorption via Ideal Adsorbed Solution Theory (IAST). Accordingly, IAST-BET provided an accurate description of MTBE/TBA binary adsorption experimental data, hence being a reliable isotherm for the design of industrial adsorption equipment for wastewater treatment especially in high concentration ranges. The kinetic study was also conducted and two common kinetic models (pseudo first-order and pseudo second-order) were used to determine kinetics parameters. The mechanism of the adsorption process was described from the intraparticle diffusion model. The kinetic data showed a closer fitness to the pseudo-second order model. Maximum values for the rate constant, k2, were obtained for MTBE and TBA adsorption, as 0.252 and 1.494 (gmg−1min−1), respectively.

The interactions of methyl tert-butyl ether on high silica zeolites: a combined experimental and computational study

In this work, the interactions of methyl tert-butyl ether (MTBE) on different dealuminated high silica zeolites were studied by means of both experimental and computational approaches. Zeolites with different textural and surface features were selected as adsorbents and the effect of their physico-chemical properties (i.e. pore size architecture and type and amount of surface OH sites) on sorption capacity were studied. High silica mordenite (MOR) and Y zeolites (both with a SiO2/Al2O3 ratio of 200) and ZSM-5 solid (SiO2/Al2O3 ratio of 500) were selected as model sorbents. By combining FTIR and SS-NMR (both (1)H and (13)C CPMAS NMR) spectroscopy it was possible to follow accurately the MTBE adsorption process on highly defective MOR characterized by a high concentration of surface SiOH groups. The adsorption process is found to occur in different steps and to involve isolated silanol sites, weakly interacting silanols, and the siloxane network of the zeolite, respectively. H-bonding and van der Waals interactions occurring between the mordenite surface and MTBE molecules were modeled by DFT calculations using a large cluster of the MOR structure where two adjacent side-pockets were fused in a large micropore to simulate a dealumination process leading to silanol groups. This is the locus where MTBE molecules are more strongly bound and stabilized. FTIR spectroscopy and gravimetric measurements allowed determination of the interaction strength and sorption capacities of all three zeolites. In the case of both Y and MOR zeolites, medium-weak H-bonding with isolated silanols (both on internal and external zeolite surfaces) and van der Waals interactions are responsible for MTBE adsorption, whereas ZSM-5, in which a negligible amount of surface silanol species is present, displays a much lower amount of adsorbed MTBE retained mainly through van der Waals interactions with zeolite siloxane network.

The Role of Silanols in the Interactions between Methyl tert-Butyl Ether and High-Silica Faujasite Y: An Infrared Spectroscopy and Computational Model Study

It is generally believed that the retention of methyl tert-butyl ether (MTBE) by zeolites is positively correlated to the silica content of these materials. Nevertheless, highly dealuminated zeolites can contain relevant amounts of silanol groups. In this study, the effect of these point defects in a zeolite Y (SiO2/Al2O3 = 200) on the adsorption of MTBE was evaluated by means of infrared spectroscopy, supported by DFT calculations. The adsorption process is found to occur in two steps, involving isolated silanol sites and the siloxane network of the zeolite, respectively, with an average loading of 1.3 molecules per cage in the first and 1.3 molecules in the second stage. Both external and internal isolated silanol groups (stretching at 3746 and 3738 cm–1, respectively) are involved in the MTBE adsorption process with the formation of H-bonded complexes and associated shifts (516 and 358 cm–1, respectively), consistent with a H-bonding strength higher for external than for the internal ones. However, MTBE is more tightly adsorbed on the internal silanols as a result of the cage confinement effect. The band assigned to the methyl symmetric stretching of the CH3O– group can be used to discriminate between H-bond and van der Waals MTBE–zeolite interactions (2843 and 2828 cm–1, respectively). Ab initio models were used to compute the harmonic frequencies of different MTBE–zeolite models and to simulate the cage confinement of one and three ether molecules.

Potential of granulated modified nanozeolites Y for MTBE removal from aqueous solutions: Kinetic and isotherm studies

Potential of granulated modified nanozeolites Y for MTBE removal from aqueous solutions: Kinetic and isotherm studies Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modified nanozeolites Y was investigated. Nanozeolite Y powders were converted into granulated zeolites and subsequently modified with two cationic surfactants (20 mmol/dm3), to be used as adsorbent. Granulated nanozeolites were characterized by BET surface area analysis, elemental analysis and X-ray diffractometer. -Hexade-cyltrimethylammonium (HDTMA-Cl) modified granulated zeolite had more effective performance than N-cetylpyridinium bromide (CPB) modified granulated zeolite. The most conventional adsorption isotherms and kinetic models were applied to describe MTBE adsorption and reaction dynamic, respectively. The equilibrium sorption data fitted the Langmuir 2 isotherm model and the kinetic study was followed the pseudo-second-order model. The maximum adsorption capacities for HDTMA-Cl modified zeolite and CPB modified granulated zeolite were 333.33 and 142.8 mg/g, respectively as calculated by the Langmuir model. This study demonstrated that the removal of mtbe by granulated modified nanozeolites Y is a promising technique.

VOCs removal from dilute vapour streams by adsorption onto activated carbon

Methyl tert-butyl ether (MTBE) is the basic oxygenated motor fuel additive in Europe and is a volatile organic compound (VOC). Many studies have been devoted to identify the sources of this polluting compound in the environment, with special concern to shallow groundwater contamination.In this work, original experimental data from the adsorption of vapours mixtures of MTBE, cyclohexane and air onto commercial activated carbon are reported. Equilibrium adsorption data for MTBE+air and cyclohexane+air systems have been obtained from breakthrough curves and have been correlated by means of the Langmuir isotherm. Furthermore, the pseudoternary system MTBE+cyclohexane+air has been studied and the experimental competitive equilibrium data have been successfully compared with those obtained from theory of adsorption for an ideal solution.The results showed that MTBE adsorption capacity of activated carbon is strongly reduced in the presence of cyclohexane. Information on the kinetics of the adsorption operation are also reported. In particular, MTBE showed a maximum excess concentration caused by the displacement of adsorbed MTBE by cyclohexane.

Adsorption Studies for the Removal of Methyl tert-Butyl Ether on Various Commercially Available GACs from an Aqueous Medium

This study highlights the potential of four commercially available granular-activated carbons (GACs) to remove Methyl tert-butyl ether (MTBE) from an aqueous medium. Thermodynamics and kinetics parameters were elucidated. The FT-IR spectra showed decrease in peak intensity after the adsorption. The decline in the peak intensity revealed that the adsorption occurred on available active sites over the surface of the GACs. The adsorption on GACs was maximum in the pH range 7–8, with maximum adsorption capacity (47.82 mg/g, pH 8) observed with CGAC. The contact time studies showed optimum adsorption of MTBE on CGAC (67.05 mg/g) at 300 mg/L initial MTBE concentration. The applicability of the Freundlich model illustrates a multilayer adsorption process. The adsorption process is endothermic in nature. The kinetics studies showed that the adsorption follows the pseudo-second-order model on GACs and the intraparticle diffusion is the rate-controlling mechanism on CGAC.

Adsorption of DCM and MTBE from Aqueous Phase on Granular Activated Carbons: A Comparative Study

ABSTRACT The laboratory scale batch adsorption studies were conducted to investigate and compare the adsorption potential of granular activated carbons (GACs) for the removal of dichloromethane (DCM) and methyl tert-butyl ether (MTBE) from aqueous medium. The effect of various parameters such as solution pH, initial adsorbate concentration, contact time, dose of GACs, and temperature on the adsorption was studied. The optimum adsorption of DCM and MTBE on lignite granular activated carbon (LGAC) was observed at pH 7 while, optimum adsorption on bituminous granular activated carbon (BGAC) was observed in the pH between pH 6 and 8. The equilibrium data was fitted to Langmuir, Freundlich and Temkin models. Freundlich model best described the equilibrium adsorption. Contact time studies showed comparatively lower equilibration time for the adsorption of DCM on GACs. Kinetics modeling was done by applying pseudo-first-order, pseudo-second-order and Elovich models. Good agreement between experimental and theoretical adsorption capacity values along with higher regression coefficient values showed the validity of pseudo-second-order kinetics model. The thermodynamics studies showed endothermic and spontaneous process with randomness at the solid/solution interface. The adsorption of DCM and MTBE on GACs was interpreted to represent a physical adsorption.

Ultrasound Irradiation Facilitated Adsorption of MTBE from Aqueous Solution using Exfoliated Graphite

AbstractWater pollution due to the fuel additive methyl tert‐butyl ether (MTBE), which is a suspected carcinogen, is often observed in surface and ground water. The removal of MTBE from aqueous solution at a concentration of 0.00143 g/mL by using exfoliated graphite (EG) as a novel adsorbent is reported. Experiments are carried out in batch mode and the effects of several factors on the removal of MTBE are evaluated. In addition, the influence of ultrasound irradiation on MTBE adsorption is investigated. The results show that an efficient removal of MTBE from aqueous solution could be achieved by implementing an ultrasound facilitated adsorption process using EG. A maximum removal efficiency of 97 % is achieved for MTBE in controlled conditions and it is found that applying ultrasound has a significant positive effect on the removal of MTBE from aqueous solutions.

Adsorptive Removal of Volatile Organic Contaminants from Aqueous Medium by Granular Activated Carbons

ABSTRACTIn order to investigate the adsorption of dichloromethane (DCM) and methyl tert-butyl ether (MTBE) form aqueous solution onto granular activated carbons (GACs), kinetics, thermodynamics, and competitive ions studies were carried out. The optimal pH range for the adsorption of DCM and MTBE on GACs was 5.0 to 8.0. Contact time studies showed comparatively lower equilibration time for the adsorption of DCM on GACs. Isotherm studies favored the applicability of Freundlich model. Kinetics studies at different concentrations showed that the adsorption of DCM and MTBE on GACs follow the pseudo-second-order kinetics model. Weber and Morris model showed that the adsorption of MTBE at different concentration on coconut granular activated carbon (CGAC) has intra-particle diffusion as the rate controlling step. The thermodynamics parameters for the adsorption of DCM onto CGAC showed the exothermic nature of the adsorption process. The adsorption of DCM and MTBE on CGAC and wood granular activated carbon (WGAC) was physical adsorption in nature. Competitive ions studies revealed significant potential of CGAC for the removal of DCM even at higher concentrations.