Boyd Model Research Articles

Cetyltrimethylammonium bromide-treated Phragmites australis powder as novel polymeric adsorbent for hazardous Eriochrome Black T removal from aqueous solutions

The potential of cetyltrimethylammonium bromide-treated Phragmites australis powder (CTAB-PA) as a novel polymeric sorbent for Eriochrome Black T (EBT) removal was studied. CTAB impregnation process increased adsorption sites availability that led to a better interaction of EBT dye and CTAB-PA. CTAB impregnation process increased the PA monolayer adsorption capacity from 57.14 to 89.93 mg g−1. Adsorption data were modeled using chemical reaction-based kinetic models (pseudo-first-order, pseudo-second-order, and Elovich models) and diffusion-based kinetic models (Weber–Morris and Boyd models). EBT sorption kinetics could be described by the pseudo-second-order model having film diffusion as the main rate-limiting step. Adsorption data for both adsorbents were fitted to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models, and best fitting was obtained with Langmuir model. Thermodynamic functions indicated that EBT adsorption onto PA and CTAB-PA was an exothermic and physical process. CTAB-PA burning behavior showed that this novel adsorbent can be considered as flame-retarding material. Adsorption–desorption experiments revealed that CTAB-PA could be reused up to five cycles with recovery percentage values maintained higher than 71%. CTAB-PA, a low-cost, durable, flame-retarding, and reusable material, was found to be an attractive candidate for EBT removal from water.

Synthesis of nitrogen-rich hollow microspheres for CO2 adsorption

The nitrogen-rich hollow microspheres (MFM) with different pore sizes have been synthesized by using melamine, m-phenylenediamine and paraformaldehyde as monomer, different particle sizes of SiO2 microsphere as template, and water as solvent. The specific surface area, pore volume and average pore size of the synthesized MFM were 183.67 m2/g, 0.91 cm3/g and 19.8 nm, respectively. After loading polyethyleneimine (PEI), its CO2 adsorption capacity could reach 2.68 mmol/g at 60 °C, with the corresponding utilization efficiency of amino as high as 40.66%. The kinetic simulation of pseudo-first-order, pseudo-second-order and Avrami kinetic model showed that the Avrami model could better describe the adsorption process of CO2, indicating both physical adsorption and chemical adsorption in the whole process. The diffusion mechanism was simulated by using the Boyd model, the intermolecular diffusion model and the intraparticle diffusion model, showing that the porous structure of MFM was beneficial to the diffusion of CO2 in the particles. After 5 cycles, 10 cycles, 15 cycles and even after 20 cycles of adsorption–desorption, the adsorption capacity of MFM-PEI at 30 °C was nearly the same as the capacity of the fresh one, indicating the regeneration stability of the adsorbent, with great advantages in practical production.

Statistical optimization of preparing marine macroalgae derived activated carbon/iron oxide magnetic composites for sequestering acetylsalicylic acid from aqueous media using response surface methodologys

This study focuses on the optimization of synthetic conditions for preparing marine macroalgae-derived activated carbon/iron oxide magnetic composites (AC/Fe-MC) and its feasibility for the removal of acetylsalicylic acid from aqueous media. Response surface methodology coupled with a 3k Box-Behnken design was applied to determine the optimal conditions (independent variables: impregnation ratio, activation temperature, and activation time) towards two response variables (production yield and adsorption capacity). According to the analysis of variance and numerical desirability function approaches, the optimal conditions were impregnation ratio of 2.62:1, activation temperature of 727 °C, and activation time of 129 min. Physicochemical properties of the prepared composite revealed that AC/Fe-MC possesses a porous structure and superparamagnetic property, which substantially contributed to the effective adsorption capacity and separation from the solution using an external magnetic field. Adsorption kinetics and equilibrium studies delineated that the pseudo-second-order and Sips isotherm models represent the adsorption behavior of AC/Fe-MC accurately. The maximum adsorption capacity of AC/Fe-MC was found to be around 127 mg/g at 10 °C, as fitted by Sips isotherm model, which is higher than that of other adsorbents reported in the literature. Intraparticle diffusion and Boyd models suggested that the adsorption process was mainly controlled by film diffusion mechanism. Lastly, thermodynamic and isosteric heat of adsorption analyses demonstrated that the adsorption process was controlled by physisorption and exothermic mechanisms.

Adsorption of ionic liquids onto an activated carbon: kinetic modeling studies.

In this study, the uptake of hydrophobic bromide-based ionic liquids (ILs) (imidazolium, pyrrolidinium, and pyridinium) from aqueous solutions onto granulated and fabric-based microporous activated carbons (ACs). Surface characterization study shows that both ACs have basic pHpzc, like 8.7 for granulated AC and 8.0 for fabric AC. Granulated AC have ten times higher phenolic groups 0.2meqg-1 compared to fabric AC which is 0.03meqg-1. The kinetics of adsorption was remarkably slower for ILs on granulated/fabric AC than milled one. We also studied the effect of AC size on the rate of adsorption in the operating conditions. In order to improve the adsorption kinetics of ILs with ACs, different phenomenological and empirical kinetic models like as pseudo-first order, Boyd model, pseudo-second-order diffusion model and Elovich were applied on the kinetic experimental data. The analysis of kinetic specified that the adsorption mechanism of ILs onto ACs is controlled mainly by the mass transfer through the pores of ACs. So, the selection of appropriate adsorbent particle size of AC plays a main role for the development of viable IL adsorption. Graphical abstract ᅟ.

Optimization of Cu (II) biosorption onto sea urchin test using response surface methodology and artificial neural networks

Copper biosorption potential of the biomass prepared from shells of sea urchin from aqueous solutions at optimum process conditions was studied. Response surface methodology and artificial neural network combined with central composite design were used for modeling and optimization of biosorption and to study interaction effects of process variables. A two-level three-factor face-centered central composite design was used for the experimental design. The influence of pH, initial copper concentration and biosorbent dosage on biosorption of copper was investigated. Prediction capacities of both models were compared and found that response surface methodology showed better prediction performance than artificial neural networks. Kinetic data were well fitted to second-order rate equation showing maximum biosorption capacity of 15.625 mg/g for 100 mg/l metal solution concentration. It was further confirmed by fitting the data to Elovich model. Biosorption mechanism was investigated using intra-particle diffusion and Boyd models. The optimum copper removal efficiency of the biosorbent was found as 89.09%.

Removal of methylene blue from aqueous solution using cocoa (Theobroma cacao) nib-based activated carbon treated with hydrochloric acid

Chemical activation process was applied to prepare a cocoa nib-based activated carbon using potassium carbonate (K2CO3). The performance of the activated carbon in removing Methylene Blue from aqueous solution was investigated by batch adsorption studies. The adsorptive properties were studied in terms of initial concentration (C0: 100-300 mg/L) and contact time effects. The experimental isotherm data fitted well the Langmuir and Temkin models. The adsorption kinetic followed the pseudo-second-order model and Boyd model explained the mechanism of adsorption. The results indicate that the chemically produced activated cocoa nib carbon has significant potential to be used as an adsorbent material for adsorption of Methylene Blue from aqueous solution.

Removal of naphthenic acids using activated charcoal: Kinetic and equilibrium studies

This study proposes the use of activated charcoal made from Umbaúba wood as an adsorbent for the removal of naphthenic acid in an aviation kerosene model mixture. The activated charcoal was characterised as mesoporous with a carbon graphite profile and presented pHpzcequal to 10.5. The best working conditions were obtained for activated charcoal levels of <0.09 mm and 300 r min−1. The system reached the equilibrium after 360 min, without significant statistical difference for the pseudo-first- and pseudo-second-order kinetic models. The Weber–Morris and Boyd models corroborated the conclusion that adsorption is not controlled only by the intraparticle diffusion step. For the equilibrium study, the adsorptive capacity obtained was of 1.1 g g−1, with the Brunauer–Emmett–Teller model better correlating with the experimental data. Given the results obtained, the activated charcoal demonstrated to have a remarkable potential for removing naphthenic acid in an aviation kerosene model mixture.

Enhanced removal of methylene blue dye from its aqueous solutions using humic acid-functionalized alumina nanoparticles

Recently, greater emphasis has been laid on the designing of nano-materials to improve the efficiency of treatment processes. Therefore, in the wake of technological improvement, a novel adsorbent humic acid-functionalized alumina (HAFA) nanoparticles were designed and have been tested for their decolorisation potential for methylene blue dye from aqueous solutions. HAFA nanoparticles were synthesized by the precipitation method and the qualitative aspect of the synthesized nanoparticles were explored by using various techniques, namely N2 adsorption–desorption measurements, Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis and zero point charge analysis. The effects of different parameters like pH value, initial contact time and concentration of the adsorbent solution were investigated to optimized the removal of methylene blue. Rate constants determination were explored by employing pseudo-first-order, and pseudo-second-order kinetic models and the latter was found to be the best simulated. Moreover, for gaining insight into the adsorption interaction, sorption data were further interpreted through Weber–Morris and Boyd models. The adsorption equilibrium data were best elucidated by Freundlich’s isotherm model and the maximum adsorption capacity of the HAFA nanoparticles was evaluated as 438.4 mg/g at 323 K. An adsorbent reusability study suggested that HAFA nanoparticles could be efficiently used for up to five cycles without compromising the adsorption capacity. Moreover, column investigation was also conducted, and results suggested that the breakthrough time could be easily enhanced by controlling the column bed height and effluent flow rate. A maximum breakthrough of 23 h was achieved with a column bed height of 7.5 cm.

Trimellitated sugarcane bagasse: A versatile adsorbent for removal of cationic dyes from aqueous solution. Part I: Batch adsorption in a monocomponent system

Trimellitated-sugarcane bagasse (STA) was used as an environmentally friendly adsorbent for removal of the basic dyes auramine-O (AO) and safranin-T (ST) from aqueous solutions at pH 4.5 and 7.0. Dye adsorption was evaluated as a function of STA dosage, agitation speed, solution pH, contact time, and initial dye concentration. Pseudo-first- and pseudo-second-order, Elovich, intraparticle diffusion, and Boyd models were used to model adsorption kinetics. Langmuir, Dubinin-Radushkevich, Redlich-Peterson, Sips, Hill-de Boer, and Fowler-Guggenheim models were used to model adsorption isotherms, while a Scatchard plot was used to evaluate the existence of different adsorption sites. Maximum adsorption capacities for removal of AO and ST were 1.005 and 0.638 mmol g−1 at pH 4.5, and 1.734 and 1.230 mmol g−1 at pH 7.0, respectively. Adsorption enthalpy changes obtained by isothermal titration calorimetry (ITC) ranged from −21.07 ± 0.25 to −7.19 ± 0.05 kJ mol−1, indicating that both dyes interacted with STA by physisorption. Dye desorption efficiencies ranged from 41 to 51%, and re-adsorption efficiencies ranged from 66 to 87%, showing that STA can be reused in new adsorption cycles. ITC data combined with isotherm studies allowed clarification of adsorption interactions.

Equilibrium, Kinetic and Adsorption Mechanisms of Chromium (VI) on Characterized Activated Carbon Synthesized from Phosphoric Acid Activation of Coconut Shells

Over the years, water pollution due primarily to the discharge of toxic heavy metals from industrial activities has served as a major challenge in our quest to provide clean drinking water to millions of people across the world. Numerous cheap and environmentally friendly methods and technologies have been developed for the treatment of wastewater contaminated with heavy metals. Key among these technologies is the use of adsorbent as it is the most economical and efficient. In this present study, coconut shells were used to develop microporous adsorbent (activated carbon) through chemical activation by phosphoric acid (H3PO4). An analysis of the effect of various process parameters such as pH, temperature, initial metal ion concentration, adsorbent dose and contact time was conducted through batch adsorption of hexavalent chromium [Cr (VI)] on prepared AC sample. Initial Cr (VI) concentration was investigated through a range of 10 – 50 mg/L with the study showing an optimum concentration for AC of 20 mg/L for percentage removal (93.3%) but adsorption capacity (Qe) was highest for 50 mg/L (4.512 mg/g). The optimum conditions for adsorbent dose, contact time and temperature were determined as 6 g/L, 100 minutes and 30°C respectively for the prepared AC. Maximum adsorption was recorded for pH (2) at 88.2 5% (removal) and 4.41 mg/g (adsorption capacity) for AC. The experimental data obtained were modelled using various isotherms, including adsorption equilibrium isotherms, adsorption kinetic study and adsorption mechanisms with positive correlations (better fit) obtained for Freundlich isotherm, D-R isotherm (slightly), pseudo-second-order kinetic and Boyd models.

Eggshell as a New Biosorbent for the Removal of Pharmaceuticals From Aqueous Solutions

The suitability of chicken eggshell as a novel sorbent for removal of pharmaceuticals (dexamethasone (DEX), febantel (FEB), praziquantel (PRAZ), procaine (PROC), and tylosin (TYL)) from water is investigated. Batch sorption experiments are performed to detect the effect of the initial concentration of pharmaceuticals, contact time, and temperature on the eggshell sorption capacity. The eggshell sample is characterized using Fourier transform IR spectroscopy, scanning electron microscopy combined with energy dispersive spectroscopy, and with particle and pore size distribution analyses. Equilibrium data are analyzed using Freundlich and Dubinin–Radushkevich isotherms. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) are calculated in order to predict the sorption nature. The results indicate that the sorption process is spontaneous and exothermic for PROC; spontaneous and endothermic for DEX, FEB, TYL; and non‐spontaneous and exothermic for PRAZ. According to the experimental results, chicken eggshell as mesoporous sorbent can be successfully used as an alternative and low‐cost biosorbent. The kinetic experimental data are fitted by Lagergren's and Ho's pseudo‐second‐order model. Kinetic parameters, rate constants, equilibrium sorption capacities, and correlation coefficients are estimated and discussed for both kinetic models. The pseudo‐second‐order model is suitable for prediction of sorption capacities. The mechanism of the sorption process is determined by the Weber–Morris intraparticle diffusion model and Boyd model. The sorption rate of investigated pharmaceuticals to chicken eggshells is influenced by both diffusion types: intraparticle and film diffusion.

Preparation and characterization of distillers’ grain based activated carbon as low cost methylene blue adsorbent: Mass transfer and equilibrium modeling

In this study, an orthogonal array design method was employed to optimize carbon preparation from distillers’ grain (DGAC). The physical and chemical properties of the produced DGAC were characterized using scanning electron microscopy (SEM), N2 adsorption–desorption technique (Brunauer-Emmett-Teller, BET), and fourier transform infrared spectroscopy (FTIR). The BET surface area of DGAC was found to be 1430 m2/g, with average pore diameter of 2.19 nm. Batch experiments were carried out to study the adsorption of methylene blue (MB) onto DGAC. External mass transfer model, internal diffusion model, Boyd model and pseudo-second-order model were used to fit the adsorption kinetic process of MB adsorption onto DGAC. The results shows the external mass transfer model could only describe the adsorption for the initial 5 min, and later the internal diffusion in the pores of the carbon particles became a main resistance, chemisorption was also involved in the adsorption process. The adsorption equilibrium was described best by Langmuir isotherm with maximum adsorption capacity of 934.6 mg/g of MB at 55°C, thermodynamic studies confirmed that the adsorption of MB onto DGAC was spontaneous and thermodynamically favourable. These findings support the potential of using distillers’ grain as raw material to prepare well-developed porous texture adsorbent with huge MB removal capacity.

Detailed kinetics study of arsenate adsorption by a sequentially precipitated binary oxide of iron and silicon

ABSTRACTThis paper comprises a comprehensive kinetic study for the adsorptive removal of As (V) from aqueous medium by mixed oxide (MO) of iron and silicon. The multi-linearity of the intraparticle diffusion model pointed towards the likelihood of both the pore and film diffusion. The Boyd model validated film diffusion to be the principal mechanism responsible for controlling the rate of the arsenate adsorption on MO. The negative entropy of activation (ΔS#) suggested the adsorption mechanism to be associative in nature. The non-negative values of ΔG# suggested the presence of an energy barrier to be surmounted for the reaction to occur.

Adsorption of Amido Black 10B from aqueous solution using polyaniline/SiO2 nanocomposite: Experimental investigation and artificial neural network modeling

The present work focused on the performance of Polyaniline/SiO2 nanocomposite for removing Amido Black 10B dye from aqueous solution. The effect of different variables, such as adsorption time, the mass of adsorbent, solution pH and initial dye concentration was studied and also was optimized by an Artificial Neural Network (ANN) method. Lagergren, pseudo-second order, Intra-particle Diffusion, Elovich and Boyd models were tested to track the kinetics of the adsorption process. The experimental data were fitted to different two-parameter, and three-parameter isotherm models, namely, Langmuir, Freundlich, Temkin, D-R, Hill, Sips and Redlich-Peterson models, and their validity was examined. The results showed that the dye adsorption process was well described by Redlich-Peterson isotherm model. Thermodynamic studies revealed that the adsorption of Amido Black 10B onto Polyaniline/SiO2 nanocomposite was endothermic. The comparison of the adsorption efficiencies obtained by the ANN model and the experimental data evidenced that the ANN model could estimate the behavior of the Amido Black 10B dye adsorption process under various conditions.

Biosorption of toxic metals using the alginate extraction residue from the brown algae Sargassum filipendula as a natural ion-exchanger

In order to aggregate extra value to dealginated seaweed waste (RES1 and RES2) and to establish a new usage for the process waste, this study evaluated the use of this biomass in the removal of toxic metals from contaminated wastewater. Both residues showed similar affinity for almost all metallic ions studied, and the comparison revealed that the largest reduction in the percentage removal was found for cadmium. It was identified a behavior typical of ion exchange, where sodium was the most released ion, mainly in the presence of Cr and Cd. The kinetic study also showed a maximum adsorption peak of nickel and zinc and this uncommon behavior may be related to the properties of each metal ion, such as strength of ionic bonds and diffusivity. The Boyd model fits indicated that the removal of chromium and cadmium is predominantly controlled by the internal diffusion, while the External Mass Transfer Resistance model showed that the Ni and Zn uptake are mainly controlled by the external diffusion. In relation to the pseudo-first order and pseudo-second model, the first better describes Ni and Zn experimental data, whereas the last one is more representative to Cd and Cr data.

Sulfate decontamination from groundwater by metal layered double hydroxides functionalized high phosphorus iron ore waste as a new green adsorbent: Experimental and modeling

The reuse of mine wastes is an efficient method to reduce disadvantages of the mining operation. High phosphorous iron ore (HPI) waste as a common waste of iron mine has been modified by Ni-Al and Ni-Fe hydroxide metals and utilized as a sulfate adsorbent. These adsorbents were characterized by XRD, XRF, FTIR, SEM, BET and TGA analyses. According to characterization studies, by loading Metal Layered Double Hydroxides (Ni-Al and Ni-Fe hydroxide metals) onto HPI Ore Waste appropriate adsorptive spaces and pores were emerged on the surface of Ni-Fe and Ni-Al HPI which were shown by enhancement intensity of OH bending vibrations in FTIR analysis, increase of Loss On Ignition (L.O.I) value in XRF analysis and the thermal stability reduction in TGA. The RSM method based on central composite design (CCD) was used to investigate the optimum condition. The amount of adsorption in optimum condition led to 34 and 29.89mg/g for Ni-Al and Ni-Fe HPI, respectively. The equilibrium studies have been carried out by the consideration of Langmuir, Freundlich, Temkin, D-R, Redlich-Peterson, Khan, and Koble–Corrigan isotherm models, which displayed that sulfate adsorption onto both adsorbents were performed favorably and chemically. Sulfate adsorption on to Ni-Al and Ni-Fe HPI occurred by the homogenous and heterogeneous process, respectively. Kinetic studies were performed by applying pseudo-first-order, pseudo-second-order and Boyd models which indicated the chemisorption interaction for all three adsorbents by a controlling step of the film diffusion. The adsorption process was modeled by the extended geometric method by an acceptable estimation fitted well with experimental data. Thermodynamic studies indicate that sulfate adsorption process onto Ni-Al and Ni-Fe HPI were exothermic and associative.

Adsorption of p-Cresol by Mesoporous Activated Carbon. II. Mechanism studies and data modeling

In this work, the adsorption mechanism of p-cresol from aqueous solution onto mesoporous activated carbon was investigated. The mechanism of the adsorption process was determined from Weber-Morris and Boyd models. By graphical and statistical analysis was demonstrated that both film-diffusion and intra-particle diffusion are concurrent in adsorption mechanism. The adsorption mechanism of p-cresol onto mesoporous activated carbon was sustained by FTIR analysis, Boehm titration and the point of zero charge of the GAC.

Metal–Organic Framework UiO-66 as an Efficient Adsorbent for Boron Removal from Aqueous Solution

Water-stable metal–organic framework (MOF) UiO-66 was studied in boron removal from water for the first time. XRD, SEM, nitrogen adsorption/desorption isotherms, and thermogravimetric analysis (TG) were employed to confirm the structure. The boron adsorption kinetics, isotherms, thermodynamics, mechanism, and recycling on UiO-66 were further investigated in batch adsorption process. UiO-66 exhibits great adsorption performance of 10.59 mmol·g–1 at 45 °C, and the adsorption process reaches equilibrium rapidly in 1 h. Pseudo-second-order model, intraparticle diffusion, and Boyd model are employed for kinetic analysis. The process is a spontaneous endothermic process controlled by entropy change rather than enthalpy change, which suggests intensive chemisorption. The adsorption capacity does not decrease obviously after four cycles. Characterization on exhausted UiO-66 with 11B MAS NMR reveals not solely interaction between boric acid and UiO-66. The XPS patterns suggest interaction with an Zr site, which is...

Synthesis, characterization and application of textile sludge biochars for oil removal

This study investigates removal of oil from wastewater using adsorbent produced from textile sludge. Textile sludge biochars (TSB) were prepared via carbonization in laboratory tube furnace for one hour under nitrogen flow. An optimization study was performed on the adsorption process by varying the type of adsorbent, contact time, pH, temperature, initial concentration of simulated oily wastewater and adsorbent dosage. Under the optimized conditions obtained, the maximum adsorption capacity of TSB was 173mg/g. The potential of TSB as oily wastewater adsorbent was proven by elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmet-Teller (BET) and Field Emission Electron Scanning Microscopy (FESEM) analyses. The kinetics of adsorption was described by pseudo-second order while adsorption equilibrium was represented by Langmuir isotherm. Boyd model and thermodynamic studies revealed that adsorption was controlled by film diffusion and physisorption. This study showed the capbility of TSB as oily wastewater adsorbent which can be regenerated using isopropanol.

Novel macroporous cryogels with enhanced adsorption capability for the removal of Cu(II) ions from aqueous phase: Modelling, kinetics and recovery studies

Novel macroporous cryogels based on jeffamine with various molecular weights were prepared via freeze-drying method and then functionalized by successful reductive amination to yield reduced cryogels. The reduced cryogels were characterized by FT-IR and SEM and then used as adsorbents for removal of Cu(II) ions from aqueous solution. Preliminary adsorption test revealed that reduced cryogels showed 5 times higher adsorption capacity than non-reduced cryogels. Maximum adsorption capacities for Cu(II) ion removal were determined as 55.00, 46.73, 34.10mg/g depending on the molecular weight of jeffamine used, at pH 5.5, temperature 55°C, dosage 80mg and initial concentration of 100ppm. Adsorption capacity of the reduced cryogels increases with increasing the initial concentration, pH, contact time and temperature but decreased with increasing adsorbent dosage. ΔH° values were calculated from the temperature dependence data and the obtained positive values indicated that the adsorption process was endothermic in nature. Performed recovery tests for the different cryogels resulted in a good response within the range of 56–70% recovery. The experimental adsorption data well fitted to Freundlich isotherm and pseudo-second-order kinetic model. The intraparticle diffusion and Boyd model confirmed that the adsorption process occurred via particle diffusion.