Morris Intraparticle Diffusion Research Articles

Energy-Efficient Synthesis of Copper Terephthalate Metal–Organic Frameworks Using Sorbitol and Choline Chloride-Based Deep Eutectic Solvents for Methylene Blue Removal

AbstractMetal–organic frameworks (MOFs) are considered promising candidates for organic pollutant remediation due to their adaptable topology, large surface area, porous structure and unsaturated metal sites. This study presents a novel, safe, environmentally friendly and energy-efficient method for synthesizing copper terephthalate metal–organic frameworks (Cu-BDC). The synthesis utilizes choline chloride/sorbitol deep eutectic solvent (DES), a green solvent, which allows for milder synthesis conditions. The use of DES in Cu-BDC synthesis was calculated to provide up to 99% energy savings compared to traditional method, showcasing the energy efficiency of this approach. Methylene blue (MB) adsorption using the synthesized samples was investigated. MB was selected as a model molecule because of its toxicity and persistence in the aquatic environment. Compared to Cu-BDC, Cu-BDC-D (synthesized form in DES) showed greater effectiveness in adsorption of MB with 98.7% removal at 10 g/L catalyst dosage, pH 7, 100 mg/L MB initial concentration and at 25 °C. The effects of various parameters, including adsorbent dosage, pH and temperature, on adsorption capacity were examined. The kinetic data were analyzed using both pseudo-first-order and pseudo-second-order kinetic models. The results indicated that the adsorption kinetics followed the pseudo-second-order model, and the Weber and Morris intraparticle diffusion model and Chrastil diffusion models were employed to further investigate the diffusion processes involved in adsorption. Additionally, the Langmuir, Freundlich and Sips isotherm models were analyzed, with the Langmuir isotherm providing the best fit. Desorption experiments demonstrated that the adsorbent could be reused up to three times. This study highlights the potential of MOF obtained in DES as an effective and sustainable adsorbent for dye removal in water treatment applications.

Enhancing Sodium Removal from Greywater using Modified Tripoli Adsorbents

Greywater, a byproduct of domestic activities, contains various contaminants including sodium ions which can adversely affect soil and plant health and industrial processes. This study explores the use of Tripoli, a sedimentary rock abundant in Jordan and its modified forms as potential adsorbents for sodium removal from greywater. X-ray fluorescence analysis revealed significant changes in chemical composition of Tripoli upon treatment with sulfuric acid and hydrochloric acid. Kinetic studies using the Weber and Morris intra-particle diffusion model demonstrated a high degree of agreement between experimental data and model predictions, with the rate constant (K) indicating enhanced intra-particle diffusion in samples treated at 1000°C. These findings highlight the potential of Tripoli and its modified forms as cost-effective and environmentally friendly adsorbents for sodium removal from greywater.

Investigation of boundary layer effect of intra-particle diffusion on methylene blue adsorption on activated carbon

Methylene blue (MB) is a model dye used in many adsorption studies, and it is chemisorbed on activated carbon (AC) adsorbent. The adsorption of an adsorbate by a natural adsorbent is a phenomenon where kinetics is often complex despite the necessity of having reliable information on such reactions which is much needed to predict the efficiency of industrial processes of which rate of adsorption plays an integral part. Such information is, at times, not available under different experimental conditions, limiting desired applications. The research reported herein was thus performed to investigate rate of adsorption of MB onto coconut shell activated carbon by fitting experimental data to kinetics and diffusion models. According to the regression analysis of linearized pseudo-order models applied for various experimental conditions, the pseudo first order (PFO) model is found to be best suited to describe the kinetics of the MB-AC system having rate constants in the range 0.0799 – 0.2437 min−1 under different experimental conditions at the ambient temperature. The rate constants determined through the PFO model at different solution temperatures are indicative of chemisorption of MB on AC surface. Application of the Webber and Morris intra-particle diffusion (IPD) model, which accounts for the boundary layer effect on mass transfer, indicates that adsorption kinetics may be controlled by both film diffusion and intra-particle diffusion sequentially, and that the thickness of the boundary layer on the AC surface, which is a measure of the intercept of the linearized Webber and Morris IPD model, is sensitive to experimental conditions. Consequently, experimental parameters would be able to control the adsorption behaviour of the MB-AC system, which can be investigated by monitoring the magnitude of the initial adsorption factor.

Preparation of amino-silane and thiosemicarbazide modified graphene oxide composite for high uptake adsorption of Hg(II) and Pb(II)

Seeking new modification adsorbents of graphene oxide with high uptake for some heavy metal ions is still the current hot-pot in adsorption technique. An amino-silanized and thiosemicarbazide modified graphene oxide adsorbent (TSCGO) was synthesized by silanized and crosslinking reaction of graphene oxide. The structure, morphology and thermostability of TSCGO were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and BET methods. The characteristic results verified that TSCGO was successfully acquired. The adsorption experiments of TSCGO for Hg2+, Pb2+, Cd2+, Zn2+ and Cu2+ showed that TSCGO owned higher uptake for Hg2+ and Pb2+ than the other ions. Main factors affecting adsorption of TSCGO for Hg2+ and Pb2+ were analyzed. The adsorption kinetics was studied using pseudo-first-order, pseudo-second-order, Elovich, Boyd, Weber and Morris models. The adsorption followed the pseudo-second-order kinetic and Weber and Morris intraparticle diffusion models. The adsorption isotherms were fitted using Langmuir, Freundlich, Temkin, Redlich-Peterson and Hill models. The best isothermal models should be Hill model for Hg2+ and Redlich-Peterson model for Pb2+. The maximum uptakes of Hg2+ and Pb2+ obtained from the Hill model were 933.2 and 890.4 mg g−1, respectively, which were much higher than those of some reported adsorbents from the Langmuir model. The adsorption of TSCGO for Hg2+ and Pb2+ was an endothermic and spontaneous chemical process. TSCGO could be effectively regenerated with EDTA. Hence, TSCGO would be a promising adsorbent for removal of Hg2+ and Pb2+ from wastewaters.

Removal of Arsenic by Adsorption using Activated Carbon Derived from Zea mays

The toxic pollutant arsenic ions present in the soil and water induce severe environmental and health issues in the North East of India and most of the Asian countries. This demand exploring the adsorption of arsenic ions in an aqueous medium by using a low-cost and non-pollutant adsorbent that is activated carbon obtained from the Poaceae family species (Zea mays). Activated carbon with calcium oxide (CaO) has been synthesized by pyrolysis at 650 ºC in the inert atmosphere. The characterization of activated carbon was done using a powder X-ray diffractometer, Fourier scanning electronic microscope, energy dispersive X-ray analysis and an inductively coupled plasma-mass spectrometer. The adsorption mechanism and efficacy of activated carbon were explored under optimized parameters such as pH of 5, 1 mg/mL of activated carbon dosage and 10 ppm of As(III) ions concentration at ambient temperature. The adsorption capacity of the activated carbon from the non-linear Sips model was found to be 8.4 mg/g and the linear Langmuir model was 29.85 mg/g. The adsorption mechanism from the non-linear, linear kinetic studies and Web Morris intraparticle diffusion model suggested the adsorption of arsenic ions by mass transfer, a diffusion mechanism as well as pseudo-second-order kinetics. Based on the results of desorption experiments, it is possible that the adsorbent can be reused for adsorption process for two cycles.

Separation of Spherical Nanosilica from Agricultural Wastes in Vietnam via Ultrasonic-Assisted Precipitation and Application for Effective Removal of Methylene Blue from Aqueous Solution

Agricultural wastes including bagasse and rice husk ashes are employed for synthesizing spherical nanosilica materials via the ultrasonic-assisted precipitation process in the present study. The comparison between them and nanosilica prepared from pure sodium silicate is also carried out. The role of the NH4OH : ethanol volume ratio is demonstrated. The obtained nanosilica is characterized by modern methods including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), infrared spectroscopy (IR), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms (BET). The nanosilica material is employed as an effective adsorbent for the removal of methylene blue (MB) from an aqueous solution. The suitable pH and adsorbent dosage are determined at 8 and 0.375 g·L−1. The adsorption isotherm study is surveyed based on Langmuir and Freundlich isotherm models. Pseudo-second-order kinetic model and Weber–Morris intraparticle diffusion model well describe the chemical nature of the adsorption. The thermodynamic parameters of the reaction are determined based on the Van’t Hoff equation.

Those That Remain: Sorption/Desorption Behaviour and Kinetics of the Neonicotinoids Still in Use

In January 2023, the derogation loophole was closed on "emergency authorisations" for the use of three out of five neonicotinoids in all EU states. In this study, we analysed the sorption/desorption behaviour and kinetic parameters of acetamiprid and thiacloprid, the two neonicotinoids that are still approved for use, either regularly or under emergency authorisations in the EU, and widely used worldwide. Sorption and desorption curves in four soils with different organic matter content were analysed using four kinetic models, namely, Lagergren's pseudo first-order model, two-site model (TSM), Weber-Morris intraparticle diffusion model and Elovich's model. Kinetic parameters were correlated to soil physico-chemical characteristics. To determine the mutual influence of soil characteristics and sorption/desorption parameters in the analysed soils, a factor analysis based on principal component analysis (PCA) was performed. Even though the two insecticides are very similar in size and chemical structure, the results showed different sorption/desorption kinetics. The model that best fits the experimental data was TSM. Thiacloprid showed a more rapid sorption compared to acetamiprid, and, in all soils, a higher proportion sorbed at equilibrium. Intra-particle diffusion seemed to be a relevant process in acetamiprid sorption, but not for thiacloprid. Desorption results showed that acetamiprid is more easily and more thoroughly desorbed than thiacloprid, in all soils. The kinetic behaviour differences stem from variations in molecular structure, causing disparate water solubility, lipophilicity, and acid-base properties.

Studies of kinetic models and adsorption isotherms: application on the interaction of insulin with synthetic hydroxyapatite

The non-stoichiometric, calcium-deficient hydroxyapatite was prepared through a low-temperature from aqueous solutions method and characterized using Physico-chemical methods. The potential of this hydroxyapatite to adsorb and release insulin from aqueous solutions was evaluated under physiological conditions. The effect of contact time and initial concentration were studied in batch experiments. The adsorption rate reached up to 81±5% in the first half-hour of contact, while the release rate of insulin incubation was about 41 ± 5% after 1 hour. The pseudo-first-order, pseudo-second-order, Elovich equation, Weber and Morris intraparticle diffusion model and Bangham’s pore diffusion model were applied to study the kinetics of the adsorption process. The pseudo-second-order kinetic model provided the best correlation R2(0.998) of the used experimental data compared to the other models. The adsorption of insulin onto hydroxyapatite was correlated well R2(0.998) with the Langmuir model as compared to Freundlich, Temkin and Dubinin–Kaganer–Radushkevich (D-K-R) models, with a maximum adsorption capacity of 24.46 mg/g. The isotherms parameters values of ΔG0, b_t and E show that the adsorption process is favorable, spontaneous, exothermic, and controlled by physisorption. The point of zero charge (pHZPC) of hydroxyapatite and the isoelectric point (pI) of insulin indicate that the interaction of insulin molecules with prepared apatite can be well described as an ions exchange reaction.

A comparative study of adsorption behavior of rifampicin, streptomycin, and ibuprofen contaminants from aqueous solutions onto chitosan: Dynamic interactions, kinetics, diffusions, and mechanisms

Adsorptive removal and dynamic interaction of three different pharmaceutical pollutants, namely rifampicin (RIF), streptomycin (STM), and ibuprofen (IBU) onto chitosan were systematically investigated using a batch adsorption technique at different processing parameters. In this study, chitosan was derived from mud-crab shells, as an innovative way to use the waste from marine foods as adsorbents. The kinetics, intraparticle diffusion, mechanism, and thermodynamics of the adsorption were systematically evaluated and analyzed using kinetic models, Boyd mass transfer and Weber–Morris intraparticle diffusion models, Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models, and the Gibbs equation. The adsorption isotherm of the larger molecules, RIF and STM, could be explained by the Langmuir isotherm model, in contrast, that of IBU, which is a much smaller molecule, followed the Freundlich isotherm model. The maximum adsorption capacity of RIF, STM, and IBU on chitosan was estimated to be 66.91 mg g−1, 11.00 mg g−1, and 24.21 mg g−1, respectively, which are higher compared to those on a variety of agricultural wastes, suggesting that this biopolymer is a potential practical and economical adsorbent to remove the pharmaceutical compounds from wastewater. The adsorption mechanism of the pharmaceutical compounds on chitosan is proposed based on the vibrational spectroscopic analyses, XRD patterns, and DSC thermograms of the biopolymer before and after adsorption process.

Evaluation of Crosslinked Sulfonated Polymers Derived from Different Resins for Removal of Ammonium Ions

AbstractAmmoniacal nitrogen is an environmental pollutant present in various effluents, such as landfill leachate. It is possible to use ion‐exchange resins in systems for tertiary treatment of effluents containing NH4+ ions and as support for NH3 recovery after treatment of these effluents by employing air stripping. This article presents an exploratory study of sorption of NH4+ ions by sulfonic resins prepared from styrene‐divinylbenzene (Sty‐DVB) copolymers with varied morphological structures: hypercrosslinked resin, a macroporous copolymer prepared by conventional aqueous suspension polymerization, and a polyHIPE copolymer. These three resins are sulfonated by employing concentrated sulfuric acid. The sulfonic resin derived from hypercrosslinked resin has the highest cation exchange capacity (5.06 meq g−1) and is selected for batch studies and column tests. The best result (removal rate of 87%) is achieved with 20 g of resin, time of 20 min, and concentration of 100 ppm. Kinetic behavior and sorption processes are best described by the pseudo‐second‐order, Weber–Morris intraparticle diffusion, and Langmuir models. The saturation point occurs when 900 mL of the NH4+ solution at 2500 ppm (15 mL min−1) is percolated through the column. The working capacity of this resin is 14.06 g cm−3. The resin can be reused during five cycles with removal efficiency between 71% and 82%.

Kinetics of Ion-Exchange Extraction of Lithium from Aqueous Solutions by Protonated Potassium Polytitanates

In this work, protonated forms of potassium polytitanate were obtained by treating the precursor in HCl solution at pH 2.0, 3.0, 4.0, 5.0, 6.0, or 7.0. The synthesized materials were studied using XRD, FTIR, and XRF. The ion-exchange properties were studied using a LiCl solution with a concentration of C(Li+) = 0.01 mol/L. It was shown that extraction of lithium by potassium polytitanates is dependent on their protonation degree. It has been established that the samples with the highest degree of protonation obtained at pH = 2.0 and 3.0 have the highest efficiency in the ion-exchange extraction of Li+ ions from an aqueous solution. For determination of exchange ion rates and the mechanism of the ion-exchange process, pseudo-first- and pseudo-second-order models as well as the Weber–Morris intraparticle diffusion model, were employed. Experimental data with their participation are in good agreement with the pseudo-second-order kinetic model. The calculated kinetic parameters were qe = 0.47–0.52 mmol/g and k2 = 0.25–0.43, depending on the protonation degree of potassium polytitanate. The obtained experimental and calculated values of the sorption capacity were compared with the cation-exchange capacity of materials studied. According to the kinetics study, the mechanism of lithium adsorption by potassium polytitanates with a higher protonation degree is the ion-exchange chemical reaction. Low-cost protonated potassium polytitanates are promising to extract Li+ ions from aqueous solutions with a low concentration, as confirmed by the analysis of the results.

Effective removal of nanoplastics from water by cellulose/MgAl layered double hydroxides composite beads

Micro/nanoplastic pollution is an emerging concern all over the world as it has a certain impact on the eco-environment and human health. In this study, cellulose/MgAl layered double hydroxides (LDHs) composite beads were prepared for the removal of polystyrene nanoparticles by utilizing the porous properties of cellulose and the unique positive charge of LDHs. The effects of pH, contact time, initial concentration, temperature, humic acid, and ionic strength on the attachment of nanoplastics were studied. The microstructure characteristics of the beads were also analyzed before and after the attachment of nanoplastics. The results indicate that nanoplastic attachment probably involves pore diffusion, hydrogen bonding, and electrostatic interactions. The attachment behavior can be successfully explained using the pseudo-second-order kinetic model (R2 = 0.964), Webber–Morris (intra-particle diffusion) model, and Langmuir isotherm model (R2 = 0.978). The maximum attachment capacity can reach 6.08 mg/g. Therefore, the cellulose/LDHs composite beads can be a promising adsorbent for removing micro/nanoplastics.

Efficient Removal of Lead and Chromium From Aqueous Media Using Selenium Based Nanocomposite Supported by Orange Peel

This study presents the synthesis of activated orange peel, derived from bio-waste (orange peel) and its doping with selenium nano-particles to enhance the adsorption capacity. The synthesized nanocomposite orange peel/Selenium (OP/Se) was applied as adsorbents for the removal of Lead (Pb) and Chromium (Cr) from synthetic waste water as an economical water cleaning technology. Orange peel/Selenium nanocomposite was characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). Scanning electron microscopy results showed the porous structure of OP/Se nanocomposite and distinct peaks observed in XRD and FTIR spectra depicted the successful synthesis of nanocomposite. Batch experiments were conducted to figure out the effect of different parameters on adsorption of Pb and Cr by using Atomic Absorption Spectroscopy. The maximum adsorption capacity of 99.9% was achieved for both lead and chromium at acidic pH. While at temperature of 60°C the maximum adsorption of 98.3 and 95.9% was found for Pb and Cr respectively. Furthermore the experimental data was examined with Pseudo-first order, first-order and Pseudo-second order kinetic model, as well as Morris Intraparticle diffusion model where the pseudo second order was best fitted which indicated the chemisorption mechanism in adsorption process. The adsorption process followed the Langmuir isotherm model verified that OP/Se nanocomposite was found to be favorable for the process of adsorption. The adsorption thermodynamics indicate that adsorption of heavy metals ions is spontaneous (ΔG° < 0) and the adsorption increases with increase in temperature which means that reaction was endothermic in nature. This study revealed that the synthesized bio-activated nanocomposite was an efficient adsorbent material for the removal of heavy metals from waste water.

Applicability of new sustainable and efficient alginate-based composites for critical raw materials recovery: General composites fabrication optimization and adsorption performance evaluation

Based on the 2020 list of raw materials for the EU, there are 30 critical minerals on the critical raw materials list, among which the rare earth elements group is placed. This study demonstrates a viable approach to the increasing possibility of the critical materials recovery through biosorption. The environmentally friendly biosorbents were prepared modifying calcium alginate with biochar and clinoptilolite. Firstly, the optimization procedure was applied for obtaining new biocomposites. After that the adsorption studies of La(III), Ce(III), Pr(III), and Nd(III) ions as a function of solution pH, biosorbent mass, interaction time, initial metal concentration, temperature, and competing ions presence were carried out using the batch mode. The kinetic studies were analyzed using the pseudo-first order, pseudo-second order, Weber and Morris intraparticle diffusion, Boyd as well as Dumwald-Wagner kinetic models. The experimental equilibrium data were fitted using the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The thermodynamic functions, i.e. ΔG°, ΔH°, and ΔS° were also determined. Importantly, the biocomposite beads were readily regenerated using diluted mineral acids (exemplary 0.1 mol/dm3 HNO3) and moreover, the adsorption effectiveness was very satisfactory even after six adsorption–desorption cycles (97%). New biocomposites as potential sorbents were characterized with ATR/FT-IR and XPS spectroscopy, SEM, EDX, OM and AFM microscopy, nitrogen adsorption, TG/DTG, CHNS, XRD as well as the sieve analysis and pHpzc measurements. After the interactions of the alginate composites with La(III) ions, a possible sorption mechanism was analyzed by ATR/FT-IR, XPS, and EDX spectroscopy.

Rapid and selective recovery of Ag(I) from simulative electroplating effluents by sulfydryl-rich covalent organic framework (COF-SH) with high adsorption capacity

The aim of current work was to explore a new material for the fast, efficient and selective recovery of precious metal silver (Ag(I)) from electroplating effluents to alleviate its high consumption and mitigate its environmental pollution. In this study, the sulfydryl-rich covalent organic framework (COF-SH) was prepared by solvothermal method. Its Ag(I) adsorption performance was evaluated by batch adsorption experiments that the effects of initial Ag(I) concentration, ratio of adsorption dosage to solution volume, adsorption time and reacting temperature were studied. The isothermal data fitted well with the Langmuir model and the maximum adsorption capacity at 298 K was up to 609.89 mg/g. The adsorption rate was very fast almost achieving adsorption equilibrium within 16 min. The adsorption rate and adsorption capacity increased with the increase in reaction temperature. The perfect fitting with pseudo-second-order kinetic model indicated the adsorption process was dominated by chemisorption process. Weber–Morris intraparticle diffusion model divided the adsorption process into three stages and temperature had a positive correlation with the first stage, external surface diffusion. The thermodynamic fitting results suggested that the adsorption process was endothermic, disordered and spontaneous. In terms of application, COF-SH achieved highly selective adsorption of Ag(I) in simulated electroplating wastewater with coexistence of multiple metal ions, especially at high acidity (≥1 M HNO3), and the increase in concentration of competing ions had no affects. In addition, 1 M HNO3 + 0.3 M thiourea (TU) could be used as desorption agent with 100% Ag(I) desorbed from the adsorbed adsorbent COF-SH-Ag.

Study on the SBA-15 Silica and ETS-10 Titanosilicate as Efficient Adsorbents for Cu(II) Removal from Aqueous Solution

The efficiency of Cu(II) removal from aqueous solution by two adsorbents, silica SBA-15 and titanosilicate ETS-10, was investigated. Effects of various experimental parameters such as: contact time, pH, initial copper concentration, adsorbent dosage, temperature were investigated in order to determine the maximum adsorption capacity of the adsorbents. The maximum adsorption capacity of silica SBA-15 was achieved at pH 5.0, and of titanosilicate ETS-10 at pH 6.0. The Freundlich, Langmuir, and Temkin isotherm models were applied in order to describe the equilibrium adsorption of Cu(II) by the studied adsorbents. Equilibrium data fitted well to the Langmuir model with a higher adsorption capacity of ETS-10 (172.53 mg·g−1) towards Cu(II) than SBA-15 (52.71 mg·g−1). Pseudo-first- and pseudo-second-order, Elovich, and Weber–Morris intraparticle diffusion models were used for description of the experimental kinetic data. It was found that the pseudo-first-order and pseudo-second-order kinetic models were the best applicable models to describe the adsorption kinetic data. Thermodynamic parameters that characterize the process indicated that the adsorption of Cu(II) onto the two adsorbents is spontaneous and endothermic.

Biosorption investigation of Cu(II) ions from aqueous solutions using sericin–alginate particles: Kinetic, equilibrium, and thermodynamic

In this study, sericin–alginate particles are produced for use as a biosorbent to remove Cu(II) ions from an aqueous solution in a batch biosorption system. Sericin is a protein present in silkworm cocoons and is considered a byproduct of the silk industry. Its use in the production of biosorbents has emerged as an environmentally friendly alternative. Sericin–alginate particles are characterized using N2 physical adsorption analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and point of zero charge. Additionally, they are evaluated via kinetic, isothermal, and thermodynamic biosorption tests. Kinetic modeling is performed using Lagergren pseudo-first-order, pseudo-second-order, Weber–Morris intraparticle diffusion, homogeneous solid diffusion, and external liquid-film diffusion models. For equilibrium modeling, the Langmuir, Freundlich, and Temkin isotherm models are applied. The Cu(II) ions biosorption is spontaneous and exothermic, as biosorption capacity decreases with temperature: 87.27 mg g-1 (20 °C), 82.54 mg g-1 (40 °C), and 76.18 mg g-1 (60 °C). Based on kinetic modeling, it is verified that internal mass transfer limits the biosorption rate. The Langmuir isotherm model shows a better fit for the biosorption equilibrium, indicating that biosorption occurs in the monolayer. Tests to evaluate the reusability of sericin–alginate particles are performed. It is discovered that even after five adsorption–desorption cycles, the biosorbent shows excellent biosorption capacity. The obtained results and a comparison of the biosorption capacity of different biomaterials demonstrate the high potential of the sericin–alginate particles as a biosorbent for Cu(II) ions.

Sorption of Ce(III) by Silica SBA-15 and Titanosilicate ETS-10 from Aqueous Solution

The adsorption capacity of two sorbents, silica SBA-15 and titanosilicate ETS-10, toward Ce(III) was tested. The obtained sorbents were characterized using X-ray diffraction, nitrogen adsorption-desorption, Scanning electron microscopy, and Fourier-transform infrared spectroscopy. The effects of solution acidity, cerium concentration, time of contact, and temperature on Ce(III) sorption were investigated. The maximum Ce(III) removal by silica SBA-15 was achieved at pH 3.0 and by titanosilicate ETS-10 at a pH range of 4.0–5.0. The Freundlich, Langmuir, and Temkin isotherm models were applied for the description of equilibrium sorption of Ce(III) by the studied absorbents. Langmuir model obeys the experimentally obtained data for both sorbents with a maximum sorption capacity of 68 and 162 mg/g for silica SBA-15 and titanosilicate ETS-10, respectively. The kinetics of the sorption were described using pseudo-first- and pseudo-second-order kinetics, Elovich, and Weber–Morris intraparticle diffusion models. The adsorption data fit accurately to pseudo-first- and pseudo-second-order kinetic models. Thermodynamic data revealed that the adsorption process was spontaneous and exothermic.

Removal of Pharmaceuticals from Water by Tomato Waste as Novel Promising Biosorbent: Equilibrium, Kinetics, and Thermodynamics

Tomato waste was studied as a low-cost biosorbent for the removal of five pharmaceuticals (dexamethasone, febantel, procaine, praziquantel, and tylosin) from water. Tomato waste was characterized chemically and microstructurally before and after simulated sorption. Sorption performance was interpreted as a function of the initial pharmaceuticals concentration, temperature, and physicochemical properties of the tomato waste. The linear, Freundlich, and Dubinin–Radushkevich (D-R) isotherms were used to describe the experimental results at different temperatures (298, 303, and 308 K). Thermodynamic parameters such as standard free energy (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were determined. Negative values of ΔG° in the temperature range of 298–308 K strongly indicate the spontaneous nature of the biosorption process. In addition, the values of ΔH° for the biosorption of dexamethasone, procaine, praziquantel, and tylosin on tomato waste were negative, indicating exothermic processes, while the positive value for febantel indicated an endothermic process. The kinetic data were analyzed using (i) kinetic models to determine the kinetic parameters (Lagergren’s pseudo-first order and Ho’s pseudo-second order) and (ii) adsorption–diffusion models to the describe transport mechanisms of pharmaceuticals from aqueous solution onto tomato waste as adsorbent (Weber–Morris intraparticle diffusion and Boyd film diffusion models).

Preparation and recycled simultaneous adsorption of methylene blue and Cu2+ co-pollutants over carbon layer encapsulated Fe3O4 /graphene oxide nanocomposites rich in amino and thiol groups

To find an efficient material to simultaneously remove the co-existed ionic dyes and toxic metal ions, in this paper, carbon layer encapsulated Fe 3 O 4 /graphene oxide nanocomposites rich in amino and thiol groups (Fe 3 O 4 @C /GO) was fabricated. With methylene blue (MB) and Cu 2+ as two different models of pollutants, the effects of time, initial concentration, pH values, and adsorbent dosage on the adsorption capacity of GO/ Fe 3 O 4 @C were conducted, respectively. A pseudo-second order rate model best simulated the kinetic adsorption process for both MB and Cu 2+ among the pseudo-first order, pseudo-second order, and Weber and Morris intra-particle diffusion models. The adsorption data were better fitted with the Langmuir adsorption isotherm model than Freundlich equation for both MB and Cu 2+ adsorption. The monolayer adsorption capacities analyzed from Langmuir model were 116.50 mg . g −1 and 76.86 mg . g −1 for MB and Cu 2+ , respectively. In MB- Cu 2+ binary system, resulted from the smaller separation factor (S F ) value of MB than Cu 2+ , MB had a suppression effect on Cu 2+ ions binding during the simultaneous adsorption process. But for the MB simultaneous adsorption and preloading, the impact of Cu 2+ ions on the MB adsorption capacity was almost negligible. Besides these important results, the easily magnetically separation and good regeneration property of Fe 3 O 4 @C /GO further indicated a kind of stable and efficient adsorbent with great potential in sewage treatment, while being very adaptable when compared with other magnetic carbon-based adsorbents. To find an efficient material to simultaneously remove the co-existed ionic dyes and toxic metal ions, carbon layer encapsulated Fe 3 O 4 /graphene oxide nanocomposites rich in amino and thiol groups were designed and synthesized as an adsorbent for recycled simultaneous removal of methylene blue (MB) and Cu 2+ co-pollutants, as well as the studies on parameters affecting adsorption capacity, kinetic, thermodynamic and mechanisms analysis. • Fe 3 O 4 @C /graphene oxide nanocomposites with amino/thiol-rich groups were fabricated. • The nanocomposites can simultaneously remove MB and Cu 2+ with a high efficiency. • Equilibrium data were well fitted by the Langmuir model for both MB and Cu 2+ . • A pseudo-second order rate model best simulated the kinetic adsorption process. • Suppression adsorption for Cu 2+ by MB was observed in the simultaneous adsorption process.