Removal of Petroleum Aromatic Hydrocarbons by Surfactant‐modified Natural Zeolite: The Effect of Surfactant (original) (raw)
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CLEAN - Soil, Air, Water, 2011
In this paper, a novel adsorbent developed by means of granulating of natural zeolite nanoparticles (i.e., clinoptilolite) was evaluated for possible removal of the petroleum monoaromatics (i.e., benzene, toluene, ethylbenzene, and xylene, BTEX). To do this, the natural zeolite was ground to produce nanosized particulate, then modified by two cationic surfactants and granulated. The effect of various parameters including temperature, initial pH of the solution, total dissolved solids (TDS), and concentration of a competitive substance (i.e., methyl tert-butyl ether, MTBE) were studied and optimized using a Taguchi statistical approach. The results ascertained that initial pH of the solution was the most effective parameter. However, the low pH (acidic) was favorable for BTEX adsorption onto the developed adsorbents. In this study, the experimental parameters were optimized and the best adsorption condition by determination of effective factors was chosen. Based on the S/N ratio, the optimized conditions for BTEX removal were temperature of 408C, initial pH of 3, TDS of 0 mg/L, and MTBE concentration of 100 mg/L. At the optimized conditions, the uptake of each BTEX compounds reached to more than 1.5 mg/g of adsorbents.
Minerals Engineering, 2010
This paper describes studies of surface modification of a natural Chilean zeolite with cetyl trimethylammonium bromide (CTAB), to investigate the adsorption efficiency for the removal from aqueous solution of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS), at bench scale. Modification of the zeolite with CTAB (named ZMS) was based on the external cation exchange capacity (ECEC) of 0.11 meq g À1 . The medium pH influences the SDBS ions adsorption rate onto ZMS and the adsorption followed the pseudo-second-order kinetic model. Equilibrium data showed excellent correlation with the Langmuir isotherm model. The adsorption capacities depended on maximum uptakes followed the CTAB concentration or coverage ranging from 40% to 660% of the ECEC. The maximum adsorption capacity of 30.7 mg SDBS g À1 was obtained at 660% of ECEC value. These data contribute for the understanding of mechanisms involved in zeolite modification and provide same practical clues to improve the adsorption efficiency (uptake capacity) of anionic surfactants. Results were discussed in terms of interfacial and solution chemistry phenomena.
Journal of Chemical & Engineering Data, 2014
The adsorption of aqueous solutions of BTEX (benzene, B; toluene, T; ethyl benzene, E; and xylenes, X) on hydrophobically modified zeolite was investigated. Multicomponent kinetics and equilibrium studies were carried out using a batch system. Furthermore, a mathematical model was studied that considers the mass transfer kinetics in a fixed-bed adsorption system. The influences of external mass transfer as well as the constant adsorption equilibrium and intraparticle diffusion resistance on breakthrough curves were evaluated. The adsorption kinetics was adjusted to the homogeneous diffusion model. The breakthrough times of the BTEX compounds increased with an increase in the bed height of the adsorbent and decreased with an increase in the flow. The mathematical model and numerical methodology that were applied represented the data of the present adsorption process with good accuracy.
Increases in environmental pollutants led to use of natural low cost materials such as zeolite, which prove their effective in water treatment. Natural zeolite obtained from Jabal Hannoun (local) and imported zeolites, clinoptilolite-rich tuff obtained from U.S.A, Syrian zeolitic tuff, and synthetic faujasite-13X were used as adsorbent. Characterization of raw and modified zeolite has been studied to verify their physical chemical and mineralogical properties, in order to note any changes occur during the modification of zeolite. The feasibility of using surfactant-modified zeolite to remove aniline and its derivatives from water in the broad band of concentrations (5-200 mg L-1) was evaluated by batch experiments. The results showed that a significant increase in aniline and its derivatives sorption capacity could be achieved at the loading level of hexadecyltrimethylammonium, a cationic surfactant, on zeolite surfaces at monolayer coverage. Adsorption equilibrium was carried out at different initial concentrations and different pH varies from 3 to 11. Langmuir and Freundlich adsorption isotherms were applied to the experimental data. The data best fitted the Freundlich model. It was found that the aniline removal efficiency by using clinoptilolite-rich tuff has the highest maximum adsorption 50% compared to the other zeolite. The maximum efficiency removal for N-Methylaniline reached upto 69.5% by using Syrian-zeolite. A decrease in N,N-Dimethylaniline removal by surfactant-modified zeolite, and the maximum efficiency removal was 16% by using Jordanian-Faujasite. The results show that the optimum pH of the adsorption of aniline and its derivatives by surfactant-modified zeolite was almost in acidic and neutral pH conditions. Characterization of raw and surfactant-modified zeolite was carried out using several techniques such as cation exchange capacity, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and Fourier Transform Infrared Spectroscopy. UV/VIS spectrophotometer was used in equilibrium analysis.
Activated natural zeolites for petroleum hydrocarbons adsorption
Studia Universitatis Babeș-Bolyai Chemia
This study was carried out with the aim of increasing and determining the activated zeolites' adsorption capacity by testing their efficiency on petroleum hydrocarbons. Natural zeolite samples were sequentially studied after thermal and chemical activations. The results indicated that after the activations, the zeolite samples gained an increasing adsorption capacity of petroleum hydrocarbons. Furthermore, the zeolites with small particulate sizes (<10 µm) have a higher adsorption capacity than the zeolites with a granulometry of 1-3 mm. The metal content ranged between 4200-7400 mg/kg Na, 15090-22990 mg/kg Ca, 2670-3950 mg/kg Mg, 19470-19670 mg/kg K, 6140-7210 mg/kg Fe and 149-178 mg/kg Mn. Mineralogical analyzes (X-ray diffraction-XRD and scanning electron microscopy-SEM) were applied for the characterization of the zeolites. According to the XRD results, the zeolites are characterized by a 64 % crystallization level. The main mineral which was determined was Clinoptilolite-Ca. The SEM micrographs indicate the morphology of zeolite surfaces.
Health Scope, 2016
Background: High concentrations of natural organic matter (NOM) may cause the production of harmful compounds in treated drinking water. Surfactant-modified zeolites (SMZs) with various loadings of sodium dodecyl sulfate (SDS) have been used as adsorbents to remove NOM from aqueous solution. SMZ has presented higher NOM adsorption more efficiency than natural zeolite. NOM affects the quality of drinking water in several points. Objectives: The purpose this study was to investigate the SDS-modified isotherm of natural Iranian zeolite obtained from Semnan mines, for the removal of NOM from aqueous solution. Materials and Methods: The adsorption of NOM onto SDS-modified zeolite as a function of contact time, initial NOM concentrations, adsorbent dose and solution pH was investigated. The isotherm experiments were carried out with fixing the adsorbent dose and varying the initial concentration of NOM. Results: The results indicated that SDS-modified zeolite showed greatly enhanced adsorption capacity. Findings revealed that the Langmuir isotherm best described the NOM adsorption on the adsorbent. The adsorption isotherm was well fitted to the Langmuir model. The maximum adsorption capacity of SMZ with surfactant bilayer coverage for NOM was 111 mg/g at 25°C and pH = 5. Conclusions: The findings of this study showed that the modification of natural zeolites can achieve higher adsorption capacity for organics. In addition, based on the results, natural zeolite being modified with SDS as a cationic surfactant had good efficiency for the adsorption of NOM.
Jundishapur Journal of Health Sciences, 2015
Background: The presence of natural organic matter (NOM) in raw water sources is unfavorable and has long been a problem for water supply industries. Natural zeolite is a low cost material that can be found in nature. Zeolite can be modified and used for removal of NOM from aqueous solutions. Objectives: In this study, for the first time, the efficiency of modified natural Iranian zeolite obtained from Semnan mines was investigated for removal of NOM from aqueous solution. Materials and Methods: In this study, batch studies were set up to evaluate the effects of initial pH, contact time and also the initial NOM concentrations on adsorption behavior. The effective initial pH values were in acidic ranges for adsorption of the NOM by surfactant modified zeolite (SMZ). Kinetic studies showed that the adsorption of NOM by SMZ was a gradual process. Results: The batch kinetics experiments showed that NOM adsorption by the adsorbents followed the pseudo-second order model. Results showed that the acidic pH is optimum for adsorption of NOM by SMZ. Conclusions: The findings of this study show that natural zeolite modified with sodium dodecyl sulfate, as a cationic surfactant, is a promising adsorbent for removal of NOM.
The main aim of this study was to evaluate different facile and cost-effective physicochemical methods in enhancing the adsorption capacity of natural zeolite and subsequently demonstrate the removal of methylene blue (MB). Four different physicochemical methods, namely: acid treatment (AT), base treatment (BT), combined acid-thermal (ATT) and base-thermal treatments (BTT) were investigated. This was followed by understanding the impact of the physicochemical methods on the surface characteristics and properties of modified zeolite through advanced characterisations using field emission-scanning electron microscopy, Fourier-transformed infrared spectroscopy and BrunauereEmmetteTeller specific surface area and porosity measurements. Batch adsorption studies were carried out using the modified zeolite adsorbents, in order to evaluate the highest removal efficiency of MB under varying adsorption conditions of: pH, initial MB concentration and modified zeolite loading. Results showed that both the physicochemical methods of AT (using 0.4 M HCl) and BT (using 4.0 M NaOH) are able to enhance the adsorption capacity of natural zeolite from 41% to 98.8% and 52.2%, respectively. Surprisingly, the combined physicochemical methods of ATT and BTT showed a reduction in adsorption performance when benchmarked to AT and BT alone. The adsorption data were analysed and modelled using Lang-muir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models, also the adsorption kinetics were evaluated using pseudo-first and pseudo-second order models. It was found that the adsorption data and kinetics were best represented using the Koble-Corrigan and pseudo-second order models. The improvements yielded through both the AT and BT modified zeolites were found to be promising and have the potential to be used as low-cost adsorbents for wastewater treatment.
Methyl Tert-Butyl Ether Adsorption On Surfactant Modified Natural Zeolites
2010
Abstract: Surfactant-modified clinoptilolite-rich tuff was used for the removal of methyl tert-butyl ether (MTBE) from aqueous solutions. Clinoptilolite zeolite from Miyaneh region of Iran was treated with sodium chloride and then modified with hexadecyltrimethylammonium chloride (HDTMA-Cl) and n-Cetylpyridinium bromide (CPB) to be used in different experimental conditions.