Industrial Adsorption Research Articles

Trace Level Adsorption of Toxic Sulfur Compounds, Carbon Dioxide, and Water from Methane

This paper presents breakthrough curves and isotherms of the adsorption of sulfur compounds, carbon dioxide, and water from a carrier gas (methane) on a fixed solid bed at 298 K and 1.3 bar. For the investigation two industrial adsorbents (silica–alumina gel, zeolite 5A) were used. The adsorptives were prepared in trace level concentrations up to 2000 mol-ppm. Common isotherm equations were fitted to the adsorption capacities which were obtained from breakthrough curves by mass balances. Binary systems (one adsorptive in methane) and ternary systems (two adsorptives in methane) are included. Methane is used to duplicate conditions of industrial scale natural gas treatment as far as possible. Though methane is a very weak adsorptive on oxidic adsorbents the reported adsorptive capacities might be slightly lower than pure component loadings accessible from a volumetric or gravimetric method. The adsorption isotherms of the binary systems show distinctly different capacities depending on the polarity of the ...

“Multi-temperature” method for high-pressure sorption measurements on moist shales

A simple and effective experimental approach has been developed and tested to study the temperature dependence of high-pressure methane sorption in moist organic-rich shales. This method, denoted as "multi-temperature" (short "multi-T") method, enables measuring multiple isotherms at varying temperatures in a single run. The measurement of individual sorption isotherms at different temperatures takes place in a closed system ensuring that the moisture content remains constant. The multi-T method was successfully tested for methane sorption on an organic-rich shale sample. Excess sorption isotherms for methane were measured at pressures of up to 25 MPa and at temperatures of 318.1 K, 338.1 K, and 348.1 K on dry and moisture-equilibrated samples. The measured isotherms were parameterized with a 3-parameter Langmuir-based excess sorption function, from which thermodynamic sorption parameters (enthalpy and entropy of adsorption) were obtained. Using these, we show that by taking explicitly into account water vapor as molecular species in the gas phase with temperature-dependent water vapor pressure during the experiment, more meaningful results are obtained with respect to thermodynamical considerations. The proposed method can be applied to any adsorbent system (coals, shales, industrial adsorbents) and any supercritical gas (e.g., CH4, CO2) and is particularly suitable for sorption measurements using the manometric (volumetric) method.

A Template-Free, Ultra-Adsorbing, High Surface Area Carbonate Nanostructure

We report the template-free, low-temperature synthesis of a stable, amorphous, and anhydrous magnesium carbonate nanostructure with pore sizes below 6 nm and a specific surface area of ∼ 800 m2 g−1, substantially surpassing the surface area of all previously described alkali earth metal carbonates. The moisture sorption of the novel nanostructure is featured by a unique set of properties including an adsorption capacity ∼50% larger than that of the hygroscopic zeolite-Y at low relative humidities and with the ability to retain more than 75% of the adsorbed water when the humidity is decreased from 95% to 5% at room temperature. These properties can be regenerated by heat treatment at temperatures below 100°C.The structure is foreseen to become useful in applications such as humidity control, as industrial adsorbents and filters, in drug delivery and catalysis.

Synergistic effect in the simultaneous removal of binary cobalt–nickel heavy metals from effluents by a novel e-waste-derived material

Simultaneous removal of heavy metals coupled with high adsorption capacity of an adsorbent material is an ultimate target in industry for the purification of wastewater. A novel adsorbent prepared from an electronic waste-based material has been used for this purpose. The results exhibit very high removal capacities of the adsorbent for both cobalt and nickel in the single-component systems. These capacities have been compared with those of three widely-used industrial adsorbents and it has been shown that the removal capability of this novel material is well above those of the industrial ones. Moreover, the effect of pH has also been explored and it has been shown that the pH value has a drastic effect on the metal removal capacity at pH values lower than 3. Furthermore, a synergistic effect of two metals has been observed and studied in the binary metal system. The results indicate that not only the simultaneous presence of the two metals does not reduce the adsorption capacity, but also enhances their removal from the effluent.Moreover, the adsorption equilibrium modeling for the single and binary systems have been presented and it has been inferred that the Langmuir-type models can fit the single component experimental data, while the binary system can be fitted only by the modified extended Freundlich model.

Adsorption of Naphthalene, Phenanthrene and Pyrene from Aqueous Solution Using Low-Cost Activated Carbon Derived from Agricultural Wastes

In this work, the adsorption of polycyclic aromatic hydrocarbons (PAHs) from aqueous solution by rice husk activated carbon (RHAC) was compared with adsorption using conventional, powdered activated carbon as the adsorbent. The adsorbent capacity of RHAC was found to be higher than all other agricultural and industrial adsorbents evaluated. The kinetics of PAHs was similar even after 24 hours. The removal of PAH occurred in the following order: naphthalene < phenanthrene < pyrene. Our study results show that molecular weight and solubility play vital roles in the adsorption of PAH on RHAC. The study results pointed to the occurrence of an intra-particle mechanism in all cases. The isotherm models that best represented the data obtained were Freundlich for naphthalene, Redlich-Peterson for phenanthrene, and Langmuir for pyrene. The results of this study were compared with previous studies.

Potential Theory of Adsorption for Associating Mixtures: Possibilities and Limitations

The applicability of the multicomponent potential theory of adsorption (MPTA) for the prediction of the adsorption equilibria of several associating binary mixtures on different industrial adsorbents was investigated. In the MPTA, the adsorbates are considered to be distributed fluids subject to an external potential field emitted by the adsorbent. In this work, the theory was extended to include the cubic-plus-association (CPA) equation of state (EoS) for the description of the fluid–fluid interactions of associating mixtures. The Dubinin–Radushkevich–Astakhov (DRA) potential function was utilized to describe the solid–fluid interactions. The potential was extended to include adsorbate–absorbent-specific capacities rather than an adsorbent-specific capacity. Correlations of pure-component isotherms were generally found to be excellent with individual capacities, although adsorption on silicas at different temperatures still poses a challenge. The quality of the correlations was usually found to be independent of the applied EoS. Predictions for binary mixtures indicate that MPTA + SRK is superior when adsorption occurs on nonpolar or slightly polar adsorbents, whereas MPTA + CPA performs better for polar adsorbents or when the binary mixtures contain only associating compounds. Predictions were typically improved by about 3% when individual capacities were employed, but improvements in some cases were as large as 45%. When individual capacities and the best-performing EoS were used, average absolute deviations of the selectivity were as low as 7–12%. Predictions of the selectivity were generally found to be superior to predictions of the adsorbed amounts. The sensitivity of the model was also tested, and it was concluded that the predictions are very sensitive to the adsorption energies.

Resin-asphaltene concentrates as base for carbon sorbent production

Products with a substantial content of resinous-asphaltenic compounds were obtained by redox reaction of acid tar and asphalt of petroleum residue deasphaltization with propane and gasoline. Addition of their polycondensates with furfural to the charge makes it possible to produce finely porous carbon adsorbents characterized by higher selectivity in gold and silver extraction from multicomponent polymetallic solutions in comparison with industrial adsorbents.

Carbon adsorbents from of shale oils and phenols

The liquid products of shale conversion—shale oil and shale phenols (a mixture of alkylresorcinols) and their solutions in commercial furfural, which are used as a new binding agent—make it possible to form carbon adsorbents with high mechanical strength (to 97%), microporosity (to 0.70 cm3/g), and higher sorption capacity than that of industrial adsorbents. The medium-combustion-loss samples exhibited higher selectivity in the extraction of noble metals from the multicomponent polymetallic solutions than those formed of traditional wood tar. They also outperform industrial adsorbents in these characteristics. It is possible to apply them to the absorption and concentration of aromatic hydrocarbons and to use them at atomic power plants, transport, and air conditioning plants for food and vegetable storage.

Sorption Study of a Basic Dye “Gentian Violet” from Aqueous Solutions Using Activated Bentonite

Various industries like textiles, papers, food, plastics, leather, etc are great water and organic colorant users. Hence, the resulting effluents could be an important source of environmental problems, since they may contain stable and non biodegradable contaminants, like organic dyes. The treatment of which is the main scope of the present study. Different ways of dye removal from these effluents do exist, such as flotation, reverse osmosis, chemical flocculation and adsorption etc. Adsorption is used in this work for the removal of a particular basic dye, known as Gentian violet (GV) from an aqueous solution, by means of a natural clay material. The influence of various key parameters like contact time, temperature, ionic strength, etc. on the adsorbed amount of the dye was investigated, for batch conditions. A kinetic study was also carried out, the obtained experimental results were tested against the pseudo first order and the pseudo second order equations. An analysis of the obtained equilibrium data showed that the dye adsorption is best described by the Langmuir model. The obtained results showed that temperature did enhance the Gentian violet dye retention process onto the considered bentonite whereas the obtained thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. The simultaneous presence of methylene blue, which is another colorant compound, with the Gentian violet was also considered. The clay materials showed a better affinity for the first one i e. methylene blue. In conclusion and according to the obtained results, the clay material may be recommended as an industrial adsorbent for the treatment of effluents containing Gentian violet (GV).

Separation of CO2–CH4 mixtures in the mesoporous MIL-100(Cr) MOF: experimental and modelling approaches

Carbon dioxide is the main undesirable compound present in raw natural gas and biogas. Physisorption based adsorption processes such as pressure swing adsorption (PSA) are one of the solutions to selectively adsorb CO(2) from CH(4). Some hybrid crystalline porous materials that belong to the family of metal-organic frameworks (MOFs) show larger CO(2) adsorption capacity compared to the usual industrial adsorbents, such as zeolites and most activated carbons, which makes them potentially promising for such applications. However, their selectivity values have been most often determined using only single gas adsorption measurements combined with simple macroscopic thermodynamic models or by means of molecular simulations based on generic forcefields. The transfer of this systematic approach to all MOFs, whatever their complex physico-chemical features, needs to be considered with caution. In contrast, direct co-adsorption measurements collected on these new materials are still scarce. The aim of this study is to perform a complete analysis of the CO(2)-CH(4) co-adsorption in the mesoporous MIL-100(Cr) MOF (MIL stands for Materials from Institut Lavoisier) by means of a synergic combination of outstanding experimental and modelling tools. This solid has been chosen both for its fundamental interests, given its very large CO(2) adsorption capacities and its complexity with a combination of micropores and mesopores and the existence of unsaturated accessible metal sites. The predictions obtained by means of Grand Canonical Monte Carlo simulations based on generic forcefields as well as macroscopic thermodynamic (IAST, RAST) models will be compared to direct the co-adsorption experimental data (breakthrough curve and volumetric measurements).

The Effect of Thermal Treatment on the Structure of Palygorskite Used for Flue Gas SO&lt;sub&gt;2&lt;/sub&gt; Removal

Palygorskite is widely used as industrial adsorbent and also potential for flue gas desulfurization by adsorption of SO2. The effect of thermal treatment on Palygorskite’s structural properties and its performance in SO2 adsorption were investigated. The textural and structural properties of the prepared palygorskite adsorbent were characterized by X-ray diffraction, transmission electron microscopy and temperature programmed desorption. The result showed the channel of Palygorskite is partial collapsed and the structure is not changed ultimately when thermally treated below 300 °C. The structure of Palygorskite is Gradually changed when the treating temperature is higher than 300 °C and is damaged entirety till 800 °C. As a result, the adsorption capacity of SO2 on Palygorskite decreased drastically. It is suggested that the presences of surface adorbed water and zeolitic water which occupy a large number of adsorption sites are disadvantage for the adsorption of SO2, and dissimilarly the presence of crystal-bonded water is favorable.

Adsorption of Lactic Acid from Model Fermentation Broth onto Activated Carbon and Amberlite IRA-67

The aim of this study was to compare the adsorption efficiency of lactic acid onto activated carbon and Amberlite IRA-67, and to define the adsorption isotherms. Activated carbon is a well-known industrial adsorbent and was used in this study; Amberlite IRA-67 is a weakly basic polyacrylic resin with a tertiary amine functional group. Adsorption efficiencies of activated carbon and Amberlite IRA-67 were compared with respect to their percentage of removal acid. The result of this comparison is that Amberlite IRA-67 is more efficient than activated carbon. Each of these adsorbents is in compliance with both the Freundlich and Langmuir isotherms.

Modelling diffusion and adsorption of As species in Fe/GAC adsorbent beds

AbstractBACKGROUND: Arsenic decontamination of drinking water by adsorption is a simple and robust operation. When designing packed bed adsorbers for arsenic, the main problems are the slow diffusion kinetics of As in microporous media and the lack of simple equations for predicting the performance of the equipment. Commercial iron‐doped granular activated carbon adsorbents (Fe/GAC) for groundwater arsenic abatement were studied in this work. Basic parameters for arsenate (AsV) adsorption were measured and their performance at larger scale was simulated with an approximate analytical model.RESULTS: In the 0–300 µgAs L−1 range, the AsV adsorption isotherm on Fe/GAC was found to be approximately linear. Assuming Henry's law for adsorption and homogeneous surface diffusion with constant diffusivity for intrapellet mass transfer, an approximate model for flow and adsorption of arsenate inside packed bed adsorbers was developed, and reduced to an analytic compact solution using the quasi‐lognormal distribution (Q‐LND) approximation. The use of this model with fitted and reported parameters enabled the approximate simulation of industrial adsorbers and home point‐of‐use filters. Results show that industrial adsorbers meet the breakthrough condition with incomplete utilization of the adsorbent unless convenient process configurations are used. In point‐of‐use systems with short residence times intraparticle diffusion would drastically reduce the adsorbent performance.CONCLUSION: Assuming linear adsorption of AsV over Fe/GAC, an analytical approximate solution for flow and adsorption in packed beds can be obtained. The model seems to represent correctly the main features of industrial and home filters, however, more experimental data is necessary for scale‐up purposes. Copyright © 2011 Society of Chemical Industry

Alteration of cameroonian clays under acid treatment. Comparison with industrial adsorbents

In view to evaluate an alternative local cheaper source for vegetable oil refiners, three cameroonian clays containing swelling (smectites) and non-swelling (kaolinite) clay minerals were treated with sulphuric acid solutions at concentrations of 1, 2, 4 and 8 N at 80 °C for 2 h. Their alteration and resulting products were characterized by XRD, FT-IR-spectroscopy, chemical analyses, along with TEM-EDS, nitrogen adsorption isotherms at 77 K, and compared with industrial bleaching earths. Acid treatment of Cameroonian clays leads to the classically observed cristallochemical and textural modifications. The plot of TEM-EDS data in Al 2O 3/SiO 2 and Fe 2O 3/Al 2O 3 diagrams indicate that upon acid treatment, clay particles principally move towards the SiO 2 pole, consistent with the formation of an amorphous compound mainly siliceous as the result of acid activation. Concomitantly, a progressive decrease in cation exchange capacity (CEC) was observed with increasing sulphuric acid concentrations while both specific surface area and mesoporosity of the studied materials increase. Elemental analyses, X-ray and spectroscopy data reveal that acid activation affects both the octahedral and the tetrahedral sheets. The analysis of their reactivity shows that clays with high amounts of smectite are more sensitive to acid leaching than those with relative large kaolinite contents. Further, upon acid treatment, most trace and rare earth elements are leached, and the amount of toxic elements (e.g. Cd, Pb, Ni, Cu, As, Zn) in the by-products is low (< 50 mg/kg). Mineralogy, chemical analyses and textural properties of the activated products match the specifications of industrial adsorbents. Therefore, activated Cameroonian clays are expected to perform well in respect with decolorization of vegetable oils.

Characterisation of lignite as an industrial adsorbent

An alternative use of the abundant and inexpensive lignite (also known as brown coal) as an industrial adsorbent has been characterised. The adsorptive properties of two Victorian lignite without any pre-treatment were investigated using the cationic methylene blue dye as a model compound in aqueous solutions. Two commercial activated carbon products were also studied for comparison. The adsorption equilibrium of the four adsorbents was better described by the Langmuir isotherm model than the Freundlich model. The adsorption capacities of the two untreated lignite adsorbents, Loy Yang and Yallourn, calculated using Langmuir isotherms were 286 and 370mg/g, respectively, higher than a coconut shell-based activated carbon (167mg/g), but lower than a coal-based activated carbon (435mg/g). Surface area results suggested that larger micropores and mesopores were important for achieving good methylene blue adsorption by the activated carbons. However, FTIR and cation exchange capacity analyses revealed that, for the lignite, chemical interactions between lignite surface functional groups and methylene blue molecules occurred, thereby augmenting its adsorption capacity.

How does CO capture process on microporous NaY zeolites? A FTIR and DFT combined study

Reliable experimental IR and theoretical approaches, both investigating CO adsorption on NaY faujasites, are supporting that CO capture occurs through the completion of the vacant coordination of Na(+) cations located in the accessible S(II) sites. As a result, carbonyl adsorbed species are formed by the capture of one, two or three CO molecules and are experimentally discernable by their respective IR positions that are down-shifted by an average 11-12 cm(-1) value for each captured CO molecule. DFT analysis is proposed for comparison and reproduces well the observed experimental shift of the ν(CO) positions of the different polycarbonyls of interest. In addition, the effect of Si or Al composition surrounding the SII Na(+) cation is investigated and results suggest that polycarbonyls that are formed might be in connection with the acidic strength of the cationic sites. This combined study completes and improves the understanding of the complex issue of CO adsorption at 80 K widely used as a model to explain how physical adsorption takes place in NaY faujasites working as an efficient industrial adsorbent in gas separation or gas purification processes.

Adsorption and Ion Exchange: Basic Principles and Their Application in Food Processing

A comprehensive overview of adsorption and ion exchange technology applied for food and nutraceutical production purposes is given in the present paper. Emanating from these fields of application, the main adsorbent and ion-exchange resin materials, their historical development, industrial production, and the main parameters characterizing these sorbents are covered. Furthermore, adsorption and ion exchange processes are detailed, also providing profound insights into kinetics, thermodynamics, and equilibrium model assumptions. In addition, the most important industrial adsorber and ion exchange processes making use of vessels and columns are summarized. Finally, an extensive overview of selected industrial applications of these technologies is provided, which is divided into general applications, food production applications, and the recovery of valuable bio- and technofunctional compounds from the byproducts of plant food processing, which may be used as natural food additives or for their potential health-beneficial effects in functional or enriched foods and nutraceuticals.

Alkali solid-state conversion of kaolin and zeolite to effective adsorbents for removal of lead from aqueous solution

The adsorption of lead [Pb(II)] ions onto adsorbents prepared by alkali solid-state conversion of kaolin and natural zeolite mixture was investigated. The adsorption isotherms were obtained and the Langmuir parameters were calculated in order to make a comparison between the adsorption capacities of synthesized adsorbents and those of their constituents. The synthesized adsorbents exhibit much higher adsorption capacity than kaolin and zeolite. Therefore, the low-cost adsorbent based on kaolin and Jordanian zeolite has important features since it has an extraordinary adsorption capacity towards Pb(II) ions (157 mg Pb(II)/g at pH 6.0 and 0.1 M ionic strength). Furthermore, the results implied the advantage of using zeolite as filler in kaolin-based geopolymers and the advantage of using kaolin as a binder for zeolite in their use as industrial adsorbents in water purification. The adsorption capacity of the synthesized adsorbents, unexpectedly, increases with pH decrease and ionic strength increase. The XRD pattern of the synthesized adsorbent prepared from Jordanian kaolin (JK) and zeolite indicates that it is amorphous.

Lipid adsorption capacities of magnesium silicate and activated carbon prepared from the same rice hull

AbstractThis study is a comparison of the lipid adsorption capacities of synthetic magnesium silicate and activated carbon produced from rice hulls of the same origin. The lipids examined were the free fatty acids, diacylglycerols and monoacylglycerols of frying oils. Pure oleic acid, an unused sunflower frying oil and a used sunflower frying oil were used in the experiments. The produced adsorbents, magnesium silicate and activated carbon, have surface areas of 680 and 43 m2/g, respectively. The lipid adsorption capacity of the produced magnesium silicate was found as 644 mg polar compounds/g adsorbent and it is higher than the capacities of the industrial adsorbents, Magnesol XL and activated carbon. This value is only 368 mg polar compounds/g adsorbent for the activated carbon produced from the same‐origin rice hull.

Experimental determination of the loss of krypton and xenon in an adsorption purification unit of a contemporary ASU

Results are provided for a study in a laboratory test unit of the adsorption dynamics for krypton, xenon, ethane and nitrogen hemioxide (lower oxide) from air in two-layer equipment simulating an industrial adsorber of a combined purification unit (CPU) of a contemporary air separation unit (ASU). As a result of the studies, it is established that the loss of krypton in a CPU is insignificant (about 0.25%) and it is mainly determined by the presence of this component in the gas phase (air) at the end of the purification stage before the start of switching over adsorbers. The loss of xenon is more marked and it depends on the ratio of the calculated adsorber operating time (before the start of the breakthrough carbon dioxide) to the actual adsorber operating time in the purification stage. According to experimental data, the maximum loss of xenon is about 8%. The data obtained point to a marked reduction in the loss of gases in a CPU compared with regenerators used in old ASU schemes within which the losses were about 10–11% for krypton and 25–30% for xenon. It has been established by experiment that during operation of adsorbers of an industrial CPU about 18% of nitrogen hemioxide and 10% ethane is retained within them, but methane is hardly retained. The data obtained may be used in designing units for primary enrichment of krypton and xenon in an ASU.