Bentonite Adsorbents Research Articles

Purification of used Cooking Oil using a Combination of Activated Carbon and Bentonite Adsorbents

The repeated use of cooking oil at high temperatures can significantly degrade its quality, as indicated by darkened color, unpleasant odor, elevated peroxide value (PV), and free fatty acid (FFA) levels. This deterioration can contribute to health risks such as obesity, high cholesterol, heart disease, and cancer. This study investigated the effectiveness of combined activated carbon and bentonite adsorbent in reducing peroxide value and free fatty acid levels in used cooking oil. The purification method involved an adsorption process using a combination of activated carbon derived from mangosteen peel waste and bentonite. The carbonization process was carried out at 600°C for 3 hours, followed by chemical activation with H?PO? at varying concentrations of 1M, 3M, and 5M. Bentonite was activated using 5M HCl. The results demonstrated that 5 grams of activated carbon from mangosteen peel, treated with 5M H?PO?, and bentonite activated with 5M HCl, were highly effective in lowering the peroxide value and free fatty acid levels in used cooking oil. Initially, the PV of the untreated used cooking oil was 16 meq O?/kg, reduced to 3.6 meq O?/kg after treatment with the combined adsorbents. Similarly, the FFA content decreased from 2.2% to 0.09%. Both peroxide value and free fatty acid levels met the standards set by SNI 3741:2013. In conclusion, using activated carbon and bentonite is an efficient method for purifying used cooking oil, as their strong adsorption capacity effectively reduces peroxide value and free fatty acid levels.

Parametric analysis on the sulfone adsorption of using iron impregnated bentonite

Abstract Sulfur left in liquid fuel is oxidized during combustion and released into the atmosphere, contributing to the worsening of global warming. To address this, oil refineries make use of hydrodesulfurization (HDS) to reduce sulfur content in the fuel. Alternatives to HDS are being studied due to its extreme operating conditions. An alternative for treating sulfur in fuel is oxidative desulfurization, which converts sulfur to sulfones and can be extracted using adsorption methods. This study focuses on the use of bentonite modified with Fe3+ to improve its adsorptive performance for removing dibenzothiophene sulfone (DBTO) in model oil. The prepared Fe3+-bentonite adsorbents resulted in lower removal of sulfur compared to raw bentonite. This is due to Fe3+ being a hard acid, thus lowering the affinity of bentonite in adsorbing DBTO, which is a soft base. Three parameters were varied in this study, namely adsorption time, adsorbent dosage, and temperature. Results showed that DBTO removal increased with adsorption time as the DBTO molecules occupy more adsorption sites. Increasing adsorbent dosage also increases sulfur removal as it introduces more reaction sites for DBTO removal. The DBTO and bentonite system was also found to be endothermic as desulfurization increased with the temperature rise. With the data collected in this study, it is recommended to explore the possible upscaling of adsorptive desulfurization.

Penggunaan Adsorben Bentonit pada Proses Pencucian Kering dalam Pemurnian Biodiesel Minyak Jelantah

Biodiesel can be made by utilizing used cooking oil through a chemical process, namely through a transesterification reaction, namely changing the oil (triglycerides) into fatty acid methyl esters. Washing must be done to remove the remaining impurities in biodiesel. The dry washing method is purification by utilizing the adsorption process to remove impurities in crude biodiesel. Bentonite is an alternative adsorbent that can be used as dry washing in the biodiesel refining process because it is cheaper, abundant in nature and has a layered structure with the ability to swell. The purpose of the study was to determine the ability of bentonite activated with acid as a dry washing agent in biodiesel purification. The research method used is the dry washing process method using bentonite adsorbents. The application of bentonite adsorbent as much as 6 grams with a contact time of 3 hours is the best operating condition to produce biodiesel with a pH of 6 and a clarity value of 96.7.

Influência do adsorvente bentonita associado a antioxidantes hepáticos na saúde e produção de vacas leiteiras alimentadas com dietas contendo micotoxinas naturalmente produzidas

As mycotoxins are consistent contaminants in the dairy cow diet, the use of adsorbents is recommended, although there are no ideal adsorbents. Although there are studies on this subject, few have focused on chronic natural intoxications. Here, we evaluated the effect of bentonite adsorbents associated with liver antioxidants on the health and milk production of dairy cows fed a diet containing naturally-produced fumonisin, zearalenone, and deoxynivalenol. Eighteen dairy cows (bodyweight 550 ±50 kg, 5 ± 2 years old, and 30 ± 1,25 kg/day milk production) in the middle of lactation were divided into groups: treatment (TG, n = 9, 22 g/day of supplement added to diet) and control (CG, n = 9, without supplement). A physical examination was performed, weekly over 56 days and blood was collected for liver and immune assessments. Milk was harvested to evaluate milk production and content (fat protein, somatic cell count, and lactose). The additive promoted beneficial effects on the liver from the 24th day due to a decrease in the enzymatic activities of gamma-glutamyltransferase and lactate dehydrogenase and increased serum protein and albumin levels. There were improvements in health, evidenced as fewer clinical manifestations of the disease, greater leukocyte oxidative metabolism capacity, and a lower neutrophil lymphocytes ratio. The treatment also promoted a 19% increase in milk volume. It was concluded that the additive promoted health benefits and milk production in dairy cows.

Adsorption of methyl violet dye from wastewater using poly(methacrylic acid-co-acrylamide)/bentonite nanocomposite hydrogels

In this study, nanocomposite hydrogels of poly(methacrylic acid-co-acrylamide) (Poly(MAA-co-AAm)) containing different weight percent bentonite clay nanoparticles (0, 5, 10, and 15 wt. %) were used to remove methyl violet (MV) dye. FTIR, SEM, TGA, and XRD were used to analyze the properties of adsorbents. Results showed that bentonite nanoparticles were successfully distributed in the hydrogel system. Bentonite nanoparticles at 10 wt. % gave the maximum MV dye adsorption efficiency. The highest adsorption was obtained at a pH of 5, an adsorbent dosage of 1.5 g/L, a temperature of 25 °C, a contact time of 60 min, and a pollutant concentration of 10 mg/L. In thermodynamics studies, a negative values of Gibbs free energy (ΔG°) indicating that the adsorption process was spontaneous. In addition, Poly(MAA-co-AAm) hydrogels and Poly(MAA-co-AAm)/bentonite nanocomposite hydrogels gave the adsorption enthalpy (ΔH°) of –61.24 and –36.14 kJ/mol witch shows that the adsorption process is exothermic in the temperature range 25–45 °C using both adsorbents. Langmuir isotherm model was successfully applied in describing the equilibrium behavior of the adsorption process. The kinetic study showed that the pseudo-second-order model was more successful in describing the kinetic behavior of the adsorption process than pseudo-first-order and Elovich models. Poly(methacrylic acid-co-acrylamide) and poly(methacrylic acid-co-acrylamide)/bentonite adsorbents gave the α parameter values of 0.4276 and 22.15 mg.(g.min)−1, respectively indicating the high adsorption capacity of these adsorbents.

Novel Pilot-Scale Technology for Refinery Flare Flue Gas Carbon Capture and Storage Using Cost-Effective Adsorbents

This paper introduced the use of two new adsorbents, Akrosorb soda-lime and Bentonite clay, for refinery flare flue gas capture and storage. This study also developed a novel pilot plant model with 409.7149 kg/h capacity refinery flare emission capture with a novel adsorption column configuration using Akrosorb soda-lime and Bentonite clay adsorbents. The flare flue gas adsorption unit was designed, fabricated, test run, and commissioned. The adsorption column temperature is 28 ± 10 °C and has a pressure of 131.7 kPa. The novel plant RSM optimization result shows that 93.24% of CO2 and 62.18% of CO were absorbed, while 86.14% of NOx and 55.87% of HC were absorbed. The established optimum conditions of CO2, NOx, HC, and CO removal efficiency are 22 °C, 2 atm, and 60 min. The variation in flare gas emission could impact the removal efficiency of the plant. The results show the maximum adsorption ability or capacity of 314.30 mg/g, and 68.90 mg/g was reached at 60 min for Akrosorb soda-lime and molded Bentonite adsorbents. Therefore, the developed novel technology for CO2 and other GHG capture is technically feasible and friendly. The combined usage of both adsorbents will enhance the capture of GHG at a low cost compared to using Akrosorb alone as an adsorbent.

Adsorption of H2S from Hydrocarbon Gas Using Doped Bentonite: A Molecular Simulation Study.

Hydrogen sulfide is a commonly occurring impurity in hydrocarbon gases such as natural gas or landfill gas. Apart from its toxicity, H2S can cause problems in downstream processing because of corrosion of piping in the presence of moisture. Removing this contaminant using a cost-effective and energy-efficient technique such as adsorption using commonly occurring adsorbents would be beneficial both for processing and refinement of hydrocarbon gases and for their use as an energy source. In this work, grand canonical Monte Carlo simulations were performed using an ab initio forcefield to predict adsorption isotherms for methane, hydrogen sulfide, and nitrogen in bentonite doped with K+, Li+, and Na+ cations with a view to aiding the development of low-cost pressure-swing adsorption systems for the targeted removal of H2S from landfill gas or natural gas. Pure species simulations were done, in addition to considering mixtures at conditions approximating real-world natural gas fields. Highly selective targeted adsorption of hydrogen sulfide was achieved for all three doped bentonites, with the adsorbed phase consisting of almost pure H2S, although the volume of gas adsorbed differed between adsorbents. The results suggest the following ranking for the three doped bentonite adsorbents in terms of their overall performance: K+ > Li+ > Na+. By considering both the composition of the adsorbed phase and the total quantity of adsorbed gas, there may be an interplay between the gas–gas and gas–solid interactions that becomes somewhat noticeable at low pressures.

Synergistic modification of bentonite by acid activation and hydroxyl iron pillaring for enhanced dye adsorption capacity.

Despite the fact of natural abundance, low cost and environmental friendliness, the far-from-sufficient adsorption capacity of natural bentonite (BT) has limited such a promising application to remove dye pollutants. In this paper, we proposed a facile modification strategy to enhance adsorption performance of bentonite utilizing synergistic acid activation and hydroxyl iron pillaring, by which the adsorbent (abbreviated as S-Fe-BT) exhibited the highest adsorption capacity (246.06 mg/g) and a high rapid adsorption rate for a typical organic dye, Rhodamine B (RhB). This could be ascribed to the increased interlayer spacing, the increased specific surface area, and the optimized OH/Fe ratio after the synthetic modification of the pristine BT. The adsorption behavior of RhB onto S-Fe-BT was well described by the pseudo-second-order kinetic model, indicating a chemical-adsorption-controlled process. Furthermore, its adsorption isotherm matched well with the Langmuir model due to a monolayer adsorption process. This paper opens a promising direction to remove the dye pollution using low cost bentonite adsorbents treated by such a convenient modification strategy.

Removal of the residual xanthate from flotation plant tailings using modified bentonite

Xanthates are the most widely used collectors for flotation of sulfide minerals. It has been estimated that about half of the organic reagents (including xanthate) added to the flotation circuits are consumed, while the remaining half are discharged into the plant tailing. The residual xanthate in the flotation tailing can cause environmental issues through contaminating of the nearby water resources as a result of poor design of the tailings dams. In this communication two modified bentonite adsorbents, namely acid-activated (H-Be) and aluminum-pillared (Al-Be) bentonite, were synthesized and used for the removal of the residual xanthate (potassium amyl xanthate) from the synthetic and real solutions.Al-Be was found superior to H-Be in terms of adsorption performance and under optimum conditions (adsorbent dosage: 7500 mg/L; xanthate concentration: 2000 mg/L; pH = 12.2; time = 45 min) and more than 99% of the residual xanthate was removed. The kinetics data were best described by pseudo-second order model for the both adsorbents. The adsorption equilibrium isotherms were fitted by Freundlich, Langmuir, and Temkin models. The isotherm data were best-fitted to the Langmuir model, indicating monolayer adsorption of the xanthate on homogenous surfaces of the both adsorbents. The thermodynamics studies indicated that the adsorption was spontaneous, exothermic with the reducing entropy. The adsorption tests on the real samples taken from the tailing stream of a copper flotation plant (Qaleh-Zari in Iran) proved that both adsorbents are capable of removing more than 90% of the residual xanthate.

Insight into kinetics and thermodynamics properties of multicomponent lead(II), cadmium(II) and manganese(II) adsorption onto Dijah-Monkin bentonite clay

ABSTRACTMulticomponent adsorption of lead(II), cadmium(II) and manganese(II) by Nigerian Dijah-Monkin bentonite clay was investigated. The clay samples were characterized for elemental composition, cation exchange capacity and textural properties. Natural bentonite exhibits cation exchange capacity of 47.7 meq/100 g and specific surface area of 23.5 m2/g. Manganese(II) displays higher values of rate constant than lead(II) in multimetals adsorption. However, lead(II) is favorably adsorbed onto bentonite adsorbents at different concentrations studied. The multimetals adsorption onto bentonite clay samples is site selective and site specific. The pseudo-second-order kinetics model gave a better fit to the adsorption data, suggesting ion exchange and/or complex formation. The adsorption mechanism could be described by intraparticle diffusion with some restriction of metals diffusion due to film or boundary layer. Also, the multicomponent adsorption is endothermic and becomes more spontaneous as temperature increased from 303 to 338 K. Nigerian bentonite clay in its natural form is a promising adsorbent for multimetals removal in aqueous solution.

Adsorption of polynuclear aromatic hydrocarbons from aqueous solution: Agrowaste-modified kaolinite vs surfactant modified bentonite

. The adsorption efficiency of a new hybrid clay adsorbent for polynuclear aromatic hydrocarbons (PAHs) is compared with known modified clay adsorbents. The new hybrid clay adsorbent (HYCA) showed far higher adsorption capacities for the adsorption of various PAH molecules compared with sodium dodecyl sulfate modified and humic acid modified Bentonite clay adsorbents. With the new hybrid clay adsorbent (HYCA), the adsorption of some of the larger PAH molecules was complete in the first 1 h as compared with ≈ 62% and ≈ 76% observed for both humic acid modified and sodium dodecyl sulfate modified Bentonite clay adsorbents respectively. In 24 h adsorption of the PAHs was complete for all adsorbents with HYCA adsorbent showing better efficiency in the removal of the PAH molecules from aqueous solutions. No significant change was observed with increase in time up to 48 h. The adsorption was observed to be more spontaneous with HYCA adsorbent than with either modified Bentonite adsorbents. The enthalpy of adsorption did not follow any specific order and were not consistent for all PAH molecules considered. KEY WORDS: Adsorption, Polynuclear aromatic hydrocarbons, Enthalpy, Hybrid clay, Bentonite Bull. Chem. Soc. Ethiop. 2016, 30(3), 369-376DOI: http://dx.doi.org/10.4314/bcse.v30i3.5

Recent Modifications of bentonite Clay for Adsorption Applications

Adsorptive removal of toxic compounds makes practical and effective use of modified bentonite composite is a standout amongst the most appealing methodologies. Lately, the modified bentonite, a subset of advanced porous nanostructured materials, due to their unique characteristics are demonstrating awesome guarantee for better adsorption of different water contaminants. Given the significance of organic and inorganic removal, as a vital class of pollutants, this research article intends to review and summarize, quickly the as of late published research on the adequacy of various modified bentonite adsorbents under different physico-chemical process parameters in organic and inorganic contaminants adsorption. The impact of pH, the adsorption mechanism and the applicability of various adsorption kinetic and thermodynamic models are briefly discussed. The vast majority of the outcomes watched demonstrated that the adsorption kinetic and isotherm mostly followed the pseudo-second order and Langmuir models respectively.

Phosphorous adsorption using Al3+/Fe3+-modified bentonite adsorbents—effect of Al3+ and Fe3+ combinations

This study focused on assessing the impact of using a variety of Al3+ and Fe3+ combinations to prepare modified bentonite adsorbents to remove phosphorous from water. Eight adsorbents with various Al3+ and Fe3+ combinations were used; four where prepared by adding Al3+ then Fe3+ to the bentonite, and four were prepared by adding Fe3+ then Al3+ to the bentonite. The adsorption capacities and kinetics of the eight adsorbents were experimentally assessed and compared. The experimental results best fitted the Langmuir adsorption isotherm model and the kinetic data best fitted the pseudo-second-order kinetic model. The Langmuir maximum adsorption capacities of the various adsorbents were in the range of 5.6–11.3 mg P/g adsorbent. The results suggested that combining Al3+ and Fe3+ in preparing the adsorbents improved the adsorption capacity and adsorption rate compared to using Al3+ alone or Fe3+ alone. Furthermore, equal amounts of Al3+ and Fe3+ resulted in the maximum phosphorous adsorption capacities. Adding Al3+ then Fe3+ to the bentonite resulted in adsorbents with higher adsorption capacities and adsorption rates compared to adding Al3+ then Fe3+ to the bentonite. The adsorbent prepared using Fe3+ alone achieved higher adsorption capacity and adsorption rate than the adsorbent prepared using Al3+ alone, which achieved the least adsorption capacity among all adsorbents. The results confirmed that using Al3+ and Fe3+ to modify bentonite and produce phosphorus adsorbents is technically feasible and is subject to optimization.

Synthesis and characterization of bentonite based inorgano–organo-composites and their performances for removing arsenic from water

Four modifiers, amorphous iron (hydr)oxides (Fex(OH)y), manganese oxides (MnxOy) and cationic surfactants, cetyltrimethylammonium bromide (CTMAB), and poly(dimethyldiallylammonium chloride) (PDMDAAC), were used to synthesize single and complex modified bentonite. Arsenic removal by modified bentonite was investigated through effects of the type, combination and adding level of modifiers. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption-desorption were used to explore the characteristics of the original and modified bentonite. It was found that the type, combination and adding amount of modifiers would have a noticeable influence on the structure and adsorption behavior of resulting bentonite adsorbents. The complex modified bentonite, with manganese oxides and then PDMDAAC at proper addition level, showed the best adsorption properties for arsenic, which could be due to a synergistic effect between PDMDAAC and manganese oxides during modification process. PDMDAAC was found to be favorable for coating of manganese oxides onto bentonite. The adsorbing capacity of modified bentonite depended not only on specific surface area (SSA), but mainly on composite components and/or their specific surface properties.

The Desulfurization of Model Oil Products by Ferric Chloride Modified Bentonite

This work mainly involved the investigation of the adsorption of propylmercaptan on bentonite adsorbents loaded Fe3+. Several factors that influence the desulfurization capability, including Fe3+ loading, calcining temperature, and the reaction temperature, were investigated. The desulfurization was enhanced by increasing the Fe3+ loading and the best result was obtained at the FeCl3 loading of 20 wt%. The adsorption capacity of propylmercaptan on bentonite loaded with Fe3+ increased with the temperature drop. Calcining of the sorbent could also improve the desulfurization capacity, and the optimum calcining temperature was 423 K. X-ray diffraction and thermogravimetric analysis showed that the iron compounds loaded on the surface of bentonite calcined at 423 K present mostly in the form of FeCl3 and exist as amorphous materials.

Desulfurization of Model Oil via Adsorption by Copper(II) Modified Bentonite

In order to further reduce the sulfur content in liquid hydrocarbon fuels, a desulfurization process by adsorption for removing dimethyl sulfide (DMS) and propylmercaptan (PM) was investigated. Bentonite adsorbents modified by CuCl2 for the desulfurization of model oil was investigated. The results indicated that the modified bentonite adsorbents were effective for adsorption of DMS and PM. The bentonite adsorbents were characterized by X-ray diffraction (XRD) and thermal analysis (TGA). The acidity was measured by FT-IR spectroscopy. Several factors that influence the desulfurization capability, including loading and calcination temperature, were studied. The maximum sulfur adsorption capacity was obtained at a Cu(II) loading of 15 wt %, and the optimum calcination temperature was 150 o C. Spectral shifts of the ν(C-S) and ν(Cu-S) vibrations of the complex compound obtained by the reaction of CuCl2 and DMS were measured with the Raman spectrum. On the basis of complex adsorption reaction and hybrid orbital theory, the adsorption on modified bentonite occurred via multilayer intermolecular forces and S-M (σ) bonds.

Removal of phosphate from water using six Al-, Fe-, and Al-Fe-modified bentonite adsorbents

This study was part of a larger effort that involves evaluating alternatives to upgrading secondary treatment systems in the United Arab Emirates for the removal of nutrients. In this study, six modified bentonite (BNT) phosphate adsorbents were prepared using solutions that contained hydroxy-polycations of aluminum (Al-BNT), iron (Fe-BNT), and mixtures of aluminum and iron (Al-Fe-BNT). The adsorption kinetics and capacities of the six adsorbents were evaluated, and the adsorbents were used to remove phosphorus from synthetic phosphate solutions and from treated wastewater. The experimental adsorption kinetics results were well represented by the pseudo–second-order kinetic model, with R2 values ranging from 0.99 to 1.00. Similarly, the experimental equilibrium adsorption results were well represented by the Freundlich and Langmuir isotherms, with R2 values ranging from 0.98 to 1.00. The adsorption capacities of the adsorbents were dependent on the BNT preparation conditions; the types, quantities and combination of metals used; BNT particle size; and adsorption pH. The Langmuir maximum adsorption capacities of the six adsorbents ranged from 8.9–14.5 mg P/g-BNT. The results suggested that the BNT preparations containing Fe alone or in combination with Al achieved higher adsorption capacities than the preparations containing only Al. However, the Al-BNT preparations exhibited higher adsorption rates than the Fe-BNT preparation. Three of the six adsorbents were used to remove phosphate from secondarily treated wastewater samples, and the removal results were comparable to those obtained using synthetic phosphate solutions. The BNT adsorbents also exhibited adequate settling characteristics and significant regeneration potential.

Desulfurization of Model Gasoline on Modified Bentonite

This work mainly involved the investigation of the adsorption of propylmercaptan (PM) on modified bentonite adsorbents. The adsorbents were prepared by loading it separately with Cu2+, Cu+, Fe3+, and MnO4–. In general, these bentonite adsorbents tested for sulfur adsorption capacity at breakthrough followed the order: KMnO4–bentonite > Cu(I)–bentonite > Cu(II)–bentonite > Fe(III)–bentonite. Several factors that influence the desulfurization capability, including loading and baking temperature, were investigated. The results of X-ray diffraction (XRD), nitrogen sorption (BET), thermal analysis (TGA), and Fourier transform infrared (FT-IR) spectroscopy showed that the ability of modified bentonite to adsorb PM depends strongly on its surface chemistry, particularly on the presence of basic oxygen-containing groups and acid content. The high sulfur capacities of KMnO4–bentonite and Fe(III)–bentonite were because of the powerful oxidization of MnO4– and Fe3+. The high sulfur capacities of Cu(I)–bentonite and ...

Small-Sample Corrected Akaike Information Criterion: An appropriate statistical tool for ranking of adsorption isotherm models

Ranking of seven equilibrium isotherm models with various numbers of parameters (Langmuir, Freundlich, Redlich–Peterson, Sip, Langmuir–Freundlich, Fritz–Schlunder-3 parameter and Fritz–Schlunder-4 parameter) for the adsorption of Cu 2+ and Cd 2+ onto Bentonite and modified Bentonite clay was done using the small-sample-corrected Akaike information criterion (AIC c). It was observed that the Freundlich model ranked first among the adsorption isotherm models considered. In most cases, using the AIC c, the Langmuir model was ranked the second best isotherm model. Modification of Geothite, Humic acid, and Goethite + Humic acid with increase in temperature was observed to affect the Relative Akaike Weight (RAW) which describes the performance of adsorption models relative to the adsorption model with the minimum AIC c estimate. The AIC c was found to rank adsorption isotherm models better than error functions because it is more sensitive to model deviations and takes into consideration the number of parameters in an equilibrium isotherm model. AIC c was found to be more reliable in resolving very close performance of adsorption isotherms. This study showed that the conventional isotherm model, Freundlich, is a better model for describing experimental data from adsorption of Cu 2+ and Cd 2+ onto Bentonite and modified Bentonite adsorbents than models derived from them and having a higher number of parameters.

The adsorption characteristics and porous structure of bentonite adsorbents, determined from the adsorption isotherms of benzene vapor

The adsorption of benzene vapor on natural and acid activated bentonites was treated by the theory of volume filling of micropores. The micropore volume and characteristic values of the free energy of adsorptionwere determined from the adsorption isotherms. The Dubinin?Radushkevish?Stoeckli and Dubinin?Astakhov equations were used for this purpose. The results showed that natural bentonite has a more homogeneous micropore structure than the acid activated ones. The characteristic values of the free energy of adsorption for the natural bentonite were higher than those of the acid activated bentonite. This is due to differences in its structure and the pore size.