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Saturated packing is a random packing state of particles widely applied in investigating the physicochemical properties of granular materials. Optimizing particle shape to maximize packing density is a crucial challenge in saturated packing research. The known optimal three-dimensional shape is an ellipsoid with a saturated packing density of 0.437 72(51). In this work, we generate saturated packings of three-dimensional asymmetric shapes, including spherocylinders, cones, and tetrahedra, via the random sequential adsorption algorithm and investigate their packing properties. Results show that the optimal shape of asymmetric spherocylinders gives the maximum density of 0.4338(9), while cones achieve a higher value of 0.4398(10). Interestingly, tetrahedra exhibit two distinct optimal shapes with significantly high densities of 0.4789(19) and 0.4769(18), which surpass all previous results in saturated packing. The study of adsorption kinetics reveals that the two optimal shapes of tetrahedra demonstrate notably higher degrees of freedom and faster growth rates of the particle number. The analysis of packing structures via the density pair-correlation function shows that the two optimal shapes of tetrahedra possess faster transitions from local to global packing densities. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) are crystalline, three-dimensional structures with high surface areas and tunable porosities. Made from metal nodes connected by organic linkers, the exact properties of a given MOF are determined by node and linker choice. MOFs hold promise for numerous applications, including gas capture and storage. M2(4,4′-dioxidobiphenyl-3,3′-dicarboxylate)—henceforth simply M2(dobpdc), with M = Mg, Mn, Fe, Co, Ni, Cu, or Zn—is regarded as one of the most promising structures for CO2 capture applications. Further modification of the MOF with diamines or tetramines can significantly boost gas species selectivity, a necessity for the ultra-dilute CO2 concentrations in the direct-air capture of CO2. There are countless potential diamines and tetramines, paving the way for a vast number of potential sorbents to be probed for CO2 adsorption properties. The number of amines and their configuration in the MOF pore are key drivers of CO2 adsorption capacity and kinetics, and so a validation of computational prediction of these quantities is required to suitably use computational methods in the discovery and screening of amine-functionalized sorbents. In this work, we study the predictive accuracy of density functional theory and related calculations on amine loading and configuration for one diamine and two tetramines. In particular, we explore the Perdew–Burke–Ernzerhof (PBE) functional and its formulation for solids (PBEsol) with and without the Grimme-D2 and Grimme-D3 pairwise corrections (PBE+D2/3 and PBEsol+D2/3), two revised PBE functionals with the Grimme-D2 and Grimme-D3 pairwise corrections (RPBE+D2/3 and revPBE+D2/3), and the nonlocal van der Waals correlation (vdW-DF2) functional. We also investigate a universal graph deep learning interatomic potential's (M3GNet) predictive accuracy for loading and configuration. These results allow us to identify a useful screening procedure for configuration prediction that has a coarse component for quick evaluation and a higher accuracy component for detailed analysis. Our general observation is that the neural network-based potential can be used as a high-level and rapid screening tool, whereas PBEsol+D3 gives a completely qualitatively predictive picture across all systems studied, and can thus be used for high accuracy motif predictions. We close by briefly exploring the predictions of relative thermal stability for the different functionals and dispersion corrections. [ABSTRACT FROM AUTHOR]

Nanomaterials have excellent adsorption performance due to nano-effect and have been widely used in many fields. The adsorption performance of nanomaterials depends on their adsorption thermodynamics and kinetics. Here, the thermodynamic and kinetic equations of adsorption for spherical nanoparticles are first derived in theory. The mechanisms and regularities of influences of nano-effect on thermodynamics and kinetics, using nano-CdS adsorption of methylene blue as a probe, were investigated. The results show that there are significant influences of nano-effect (i.e., interface area effect and interface tension effect) on the thermodynamics and kinetics of nanoparticle adsorption. When the particle radius is larger and beyond the nanometer scale (∼100 nm), the nano-effect can be neglected. When the radius of the nanoparticle is within 10–50 nm, the nano-effect of adsorption is mainly the interface area effect. When the radius is less than 10 nm, the influences of both the interface area effect and the interface tension effect on adsorption thermodynamics and kinetics become more significant. The theoretic equations and experimental insights in the present work could provide a significant basis and reference for improving and perfecting the adsorption theory involving nanomaterials and provide guidelines for the explanations of adsorption mechanisms as well as the selection of adsorbents. [ABSTRACT FROM AUTHOR]

Methylene blue (MB) is a prevalent pollutant in organic wastewater. For this research, eucalyptus wood was used as a template, into which quartz powder dissolved in NaOH was grown, resulting in a low-cost and efficient porous silica adsorbent material (PSAM). This PSAM successfully replaces expensive materials for MB removal from water. Through the application of Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis, it became evident that PSAM displays a porous slit pore structure characterized by numerous active sites, leading to an impressive maximum specific surface area of 88.05 m²/g. The central objective of this research was to investigate the impact of experimental temperature, initial dye concentration, and pH on the adsorption process. The adsorption kinetics were analyzed using the pseudo-first-order and pseudo-second-order models, as well as the Langmuir model. Remarkably, PSAM exhibited a substantial maximum adsorption capacity of 90.01 mg/g at 293 K, achieving an adsorption rate of over 85% within a mere 10-minute timeframe. The thermodynamic analysis revealed that the adsorption of MB onto PSAM was characterized by spontaneity and accompanied by heat absorption. Fourier Transform Infrared (FTIR) and SEM comparisons of PSAM before and after adsorption indicated that MB adsorption primarily occurred through electrostatic gravitational binding. In comparison to other adsorbents, PSAM exhibited exceptional efficacy in removing MB from water. [ABSTRACT FROM AUTHOR]

In this study, the clay was interwoven with cellulose to change its structure. The product clay/cellulose was used to assess the efficacy of the methylene blue (MB) dye removal from aqueous solutions (CC25). The response surface methodology and Box-Behnken design were used to optimize the influence of crucial parameters (cellulose load, adsorbent dosage, solution pH, temperature, and contact duration) (RSM-BBD). The greatest removal effectiveness was 98.76% for a cellulose loading of 25.0% and the following working conditions, i.e., adsorbent dosage of 0.06 g/L, pH 7, temperature of 45 °C, and contact length of 20 min. At the time, the maximum adsorption capacity was 254.8 mg/g. The pseudo-second-order adsorption model, according to the adsorption kinetics research, was used to describe the process. The MB adsorption process was endothermic and spontaneous, according to computed thermodynamic functions. The developed composite material, according to our results, has a very high capacity for the color absorption and removal. [ABSTRACT FROM AUTHOR]

Treatment of heavy metal pollution in complexed states within water bodies presents significant challenges in the current water treatment field. Adsorption as a means for the removal of heavy metals is characterized by its simplicity of operation, stable effluent, and minimal equipment requirements. Metal–organic frameworks (MOFs) as adsorbents hold significant interest for applications in water treatment. In this study, we investigated a green synthesis approach for the ball-milling pretreated synthesis of UiO-66(Zr) at room temperature, abbreviated as UiO-66(Zr)-rm. Besides having the same thermal stability and crystal structure as the product from microwave-assisted synthesis (UiO-66(Zr)-mw), the resulting UiO-66(Zr)-rm features smaller particle size and superior mesoporous structure. The adsorption efficiency and mechanism for removing EDTA-chelated copper (EDTA–CuII), a complexed heavy metal in water, were extensively analyzed. UiO-66(Zr)-rm presented a maximum adsorption capacity over EDTA–CuII of 43 mg g−1 and a much higher adsorption rate (0.16 g (mg h)−1) than UiO-66(Zr)-mw (0.06 g (mg h)−1). Hierarchically mesostructured defects allow the sorbate to have more effective diffusion in a shorter time to achieve faster adsorption kinetics. Benefiting from the mild synthesis conditions and nontoxic solvents, UiO-66(Zr) has the potential to be produced at a scaled-up level, thereby exhibiting excellent adsorption performance for the removal of complexed heavy metals in the future. [ABSTRACT FROM AUTHOR]

Mesoporous carbon nitride (MCN-K) was prepared using mesoporous KIT-6 material as a template and ethylenediamine and carbon tetrachloride as N and C sources, respectively. The synthesized MCN-K was treated with sulfuric acid under different experimental conditions, thus obtaining sulfonated MCN-KS adsorbents. The effects of initial solution pH, initial dye concentration, adsorbent amount, and temperature on Rhodamine-B (Rh-B) dye removal were investigated. The XRD, FT-IR, and N2 adsorption–desorption analyses confirmed that the mesoporous carbon nitride structure was successfully synthesized. The high nitrogen content (C/N molar ratio: 4.0) of the MCN-K sample was confirmed by (carbon, hydrogen, nitrogen and sulfur) CHNS elemental analysis. The XPS analysis was used to characterize the chemical states of the C, N and S atoms in the MCN-K and MCN-KS sorbents. It was found that there was not much difference between the removal percentages (93.13–89.92%) obtained in the pH range (4–12) studied. This result was attributed to the zwitter-ion form of Rh-B. The exothermic nature of the adsorption process of Rh-B on the MCN-K sorbent was determined by adsorption experiments performed at different temperatures. Adsorption capacities obtained from the Langmuir model were 185.2–104.2 mg/g in the studied temperature range. The kinetic behavior of the adsorption process was explained by the pseudo-second-order kinetic model in terms of both correlation coefficients (R2 > 0.91) and qe (35.59–190.26 mg/g) values. When the percentages of dye removal of the un-sulfonated and sulfonated samples were compared, it was found that sulfonation increased the adsorption rate considerably but did not contribute positively to the dye removal percentage. [ABSTRACT FROM AUTHOR]

Herein, a newly synthesized intermediate, piperazine-based Schiff base (PBSB) gas sensor was fabricated by the Schiff base condensation of amino functionalized methylpiperazine with aromatic aldehyde containing nitro substituent. This organic sensor material was structurally identified with spectroscopic techniques such as FTIR, HRMS, 1H- and 13C-NMR. The designed sensor candidate was explored for its optical response to chlorinated volatile organic compounds, namely trichloroethylene, dichloromethane and chloroform in the light of structure–property relationship investigation by using surface plasmon resonance (SPR) technique. The results showed that Schiff bases could be candidates for chlorinated vapour sensing materials with their good response and reversibility. Concordantly, compound PBSB exhibited good response against chlorinated solvent vapours aided by the electron-withdrawing group on benzene ring that promoted better intermolecular interactions and opened up a new strategy to create a novel set of responsive materials for gas sensing applications. In addition, the adsorption kinetics of SPR data obtained from PBSB spun film on exposure to these chlorinated vapours at different concentrations was also evaluated using the Elovich Model. The values of the initial adsorption rate, a and Elovich constant, b were analysed depending on the concentration values and the highest values were obtained for dichloromethane between 372.92 and 4377.53 ppm/mm2. [ABSTRACT FROM AUTHOR]

This study focuses on the construction of polyvinyl chloride microcrystalline nanocellulose (PVC/NC@TALCM) nanocomposite membranes with titanium gamma aluminate (TGAL) for the adsorption and filtration of the cationic dye MB. The adsorption ability of the nanocomposite membrane was investigated by varying the dosage of the adsorbent, pH, and dye concentration. The PVC-MCNC@TGAL membrane, loaded with 5% titanium aluminate at pH 10, demonstrated a 98.6% removal efficiency for the MB dye using a dead-end filtration system. The adsorption kinetics study revealed that the adsorption process followed pseudo-second-order kinetics, indicating a chemisorption process. The Freundlich isotherm model was found to be more suitable than the Langmuir model based on the R2 value. Finally, the PVC-MCNC@TGAL nanocomposite membrane was found to be a cost-effective and eco-friendly adsorbent for the removal of MB from industrial wastewater. Additionally, the self-cleaning property of the membrane contributes to sustainability by reducing the usage of chemicals. [ABSTRACT FROM AUTHOR]

Constructing a hierarchically porous MOF@COF (HP MOF@COF) structure for enhancing the gas-adsorption kinetics. [Display omitted] For ethylene purification, C 2 H 6 -selective metal–organic frameworks (MOFs) show great potential to directly produce polymer-grade C 2 H 4 from C 2 H 6 /C 2 H 4 mixtures. Most C 2 H 6 -traping MOFs are ultra-microporous structures so as to strengthen multiple supramolecular interactions with C 2 H 6. However, the narrowed pore channels of C 2 H 6 -traping MOFs cause large guest diffusion barriers, greatly hampering their practical applications. Herein, we present a feasible strategy by precisely constructing hierarchically porous MOF@COF core–shell structures to address this issue. Additional mesoporous diffusion channels were incorporated between MOF crystals through the construction of the COF shell, thereby enhancing the gas adsorption kinetics. Notably, designing a core–shell MOF@COF structure with an optimal coating amount of mesoporous COF shell will further improve the gas diffusion rate. Breakthrough experiments reveal that the tailored MOF@COF composites can effectively achieve C 2 H 6 /C 2 H 4 separation and maintain its separation performance over five continuous measurement cycles. This investigation opens up a new avenue to solve the diffusion/transfer issues and provides more opportunities and potentials for MOF@COF composites in practical separation applications. [ABSTRACT FROM AUTHOR]

To investigate chlorine adsorption from water onto resins, some batch adsorption tests were considered. The mechanisms and characteristic parameters of the adsorption process were analyzed using isotherm models which revealed the following order (based on the coefficient of determination): Flory–Huggins (0.99) > Fowler‐Guggenheim (0.98) >, and Langmuir (0.38).The experimental data were examined using two kinetic models, including first‐ and second‐order ones with R2 value of 0.88, 0.1 respectively. According to the adsorption isotherm study, the Flory–Huggins isotherm model better fit adsorption on the surface of resin, as compared to other models. Assessing the thermodynamic parameters found out that the adsorption of Cl onto resins became an exothermic and spontaneous process. The results were then obtained. Similarly, the results of the experiment were provided via the computational fluid dynamics evaluation. Moreover, the results obtained by computational fluid dynamics were compared with the experimental data, and their accuracy was proved. Subsequently, the effects of changing the design and operating parameters, including flow rate (3, 6, 10 L min−1) and bed height (10, 20, 40 cm) on the performance of this tower were studied. The results showed that by reducing the adsorbent, the adsorbed Cl increased and a longer bed was required for adsorption, which was not cost‐effective. The amount of adsorption decreased as the flow rate increased, indicating that there was little contact between the Cl and the adsorbent. [ABSTRACT FROM AUTHOR]

This study investigates the removal of heavy metals, particularly copper and nickel, from acidic aqueous solutions using the weakly base polymeric chelating resin Dowex M-4195. The research conducts comprehensive cost–benefit and statistical analyses of various kinetic and isotherm adsorption models. The results show that the PSO and general order models provide high accuracy for the Cu2⁺ adsorption kinetics, while the Avrami fractional order model excels for Ni2⁺. In terms of the isotherm models, the Langmuir and Jovanovic models are highly accurate for both metals, with the Toth model being particularly effective for Ni2⁺ due to its ability to account for surface heterogeneity and multi-layer adsorption. This study also reveals that the kinetic adsorption process is more economically beneficial than the isotherm adsorption process, highlighting the importance of model selection for optimizing heavy metal removal. Incorporating circular economy principles, this research emphasizes the sustainability of using regenerable and reusable adsorbents like Dowex M-4195. The findings provide valuable insights for designing efficient adsorption systems, promoting environmental sustainability, and ensuring public health safety. [ABSTRACT FROM AUTHOR]

Phosphogypsum is a by-product of the wet-process phosphoric acid production, and it is rich in Ca and S. Long-term storage of Phosphogypsum can cause serious pollution to the environment; therefore, promoting the sustainable utilization of Phosphogypsum is crucial. This study proposes the use of Phosphogypsum and silicic acid in a sodium hydroxide solution for the hydrothermal synthesis of porous calcium silicate hydrate adsorbent, which is used for adsorbing Fe2+ from simulated hydrochloric acid pickling wastewater. Under the optimal synthesis conditions (37.5 g/L of NaOH, calcium/silicon ratio of 1.0, liquid/solid ratio of 15:1 mL/g, 110 °C, and 4 h), the conversion rate of SO42− in Phosphogypsum is 87.41%. Porous calcium silicate hydrate exhibits excellent OH− release capability in Fe2+-containing pickling wastewater. The adsorption process for Fe2+; is mainly chemical adsorption, involving ion exchange between Ca2+ and Fe2+, as well as complexation reactions of O-Si-O group, -OH group, and Si-O group with Fe2+. This technology aims to provide a solution for the sustainable utilization of Phosphogypsum and the recovery of Fe2+ from pickling wastewater, which has significant practical importance. [ABSTRACT FROM AUTHOR]

In this investigation, composites consisting of polypyrrole (PPy), polyaniline (PAN), and sodium alginate combined with rice husk (RH) biomass were fabricated, utilizing them as adsorbents for naphthalene. The optimization of key process variables, including pH, pesticide concentration, composite dosage, contact time, and temperature were systematically undertaken to enhance the removal efficiency of naphthalene. Notably, the composites exhibited promising efficacy in adsorbing naphthalene, with native rice husk and PPy/RH (at pH 4), PAN/RH (at pH 5), and Na-alginate/RH (at pH 6) displaying the highest removal rates. Optimized conditions for composite dosage, temperature, and contact time were determined as 0.05 g, 30 °C, and 90 min, respectively, ensuring efficient removal of naphthalene. The adsorption capacities for naphthalene were found to be 22.04, 23.15, 23.89 and 21.67 (mg/g) for RH, PAN/RH, PPY/RH and Na-alginate/RH, respectively. The Langmuir isotherm and pseudo-first-order kinetics models aptly described the adsorption process onto the composite material. The surface morphology and functional groups involved in the biocomposite formation were examined through scanning electron microscope (SEM) and Fourier-transform infrared (FTIR) techniques. These analyses confirmed that PPy, PAN, and Na-alginate composites with RH biomass exhibit high effectiveness in naphthalene removal, showcasing their potential application in the remediation of naphthalene from effluents. [ABSTRACT FROM AUTHOR]

In this research, composite materials were prepared by combining polypyrrole (PPY) and polyaniline (PAN) with Oryza sativa (OS). These biocomposites were utilized for the adsorption of Nitenpyram (insecticide), from aqueous solutions. The study involved the optimization of various process variables including contact time, pH, adsorbent dose and initial Nitenpyram concentration. The maximum sorption efficiency of OS for Nitenpyram was observed at pH 2, biosorbent dose of 0.05 g, an initial Nitenpyram concentration of 125 mg/L and contact time of 30 min. To analyze the Nitenpyram adsorption process, the adsorption data for OS and its composites (OS-PPY and OS-PAN) were subjected to equilibrium isotherms and kinetics models (pseudo-first and pseudo-second-orders). The Langmuir isotherm and pseudo-second-order explained the Nitenpyram adsorption data. Furthermore, the feasibility of the adsorption was evaluated by employing thermodynamic studies. The outcomes of the study demonstrated the promising efficiency of the synthesized biocomposites for Nitenpyram removal, which was 37.03, 43.0 and 35.71 (mg/g) in the case of OS, OS-PPY and OS-PAN composites. These findings suggest that the composites have promising potential for the removal of pesticides from wastewater, contributing to the development of effective strategies for environmental remediation. [ABSTRACT FROM AUTHOR]

In this study a low cost and easily available Black Poplar Sawdust (Populus nigra L.) was converted into an efficient adsorbent for the removal of acetamiprid (AMR) and imidacloprid (ICR) pesticides from aqueous solutions. The effect of adsorption effecting parameters including initial pesticides concentration, variations in the adsorbent amount, time of contact, and pH were investigated to understand the adsorption process of both pesticides. Further the kinetic, thermodynamic, and isotherm models were used to get an insight into the process of adsorption taking place. The results of the study suggested that the isotherm data align effectively with both the Langmuir and Temkin isotherm models (both pesticides). The maximum adsorption capacity (qm) for AMR was found to be 25.22 mg g−1, while for ICR, it was 25.65 mg g−1. Furthermore, the adsorption kinetics were best described by the pseudo-second-order model with value of R2 = 0.9934 & 0.9964 respectively for AMR and ICR. The thermodynamic analysis confirmed the spontaneity and feasibility of the adsorption process, evident from the negative ∆G° values at different temperatures. The thermodynamics parameter values also suggested that the adsorption process is physisorption and exothermic due to the negative ∆H° value. From the results it was concluded that the devised adsorbent could be effectively used in reclamation pesticides contaminated water subjected to further verifications through testing against other pesticides. [ABSTRACT FROM AUTHOR]

The present work reports the solution combustion synthesis of negatively charged cobalt oxide nanoparticles (CONPs) using glycine as a fuel. The morphology, composition, crystallinity, and surface characteristics of synthesized CONPs were confirmed. The particles were oval in shape with an average size of 10 ± 2 nm and negatively charged functional groups (C-H and N = N = N) on their surface. Batch experiments were performed to estimate the optimum values of parameter to estimate the maximum Cu(II) adsorption of CONPs, which was found to be 523 ± 12.72 mg g−1. The acid treatment achieved regeneration of loaded CONPs, and their sustainability was checked by performing adsorption–desorption experiments up to 4 cycles. The obtained results showed only a 14.4% reduction in adsorption capacity up to 4 cycles. Further, the diversified application of CONPs was examined by exposing them to synthetically prepared textile industry effluent containing multiple metal ions. The batch study data were fitted to various isotherm and kinetic models to understand the adsorption kinetics. The possible mechanism for the adsorption of Cu(II) onto CONPs has also been discussed. The antimicrobial assay results advocated that the disposal of CONPs is harmless to the ecosystem. [ABSTRACT FROM AUTHOR]

Pollutants are removed from the environment in a short time when water or biological fluids contain certain substances enter the hydrogel. In this research, we synthesized four kinds of acrylic hydrogels (performance about 50%) and applied for the kinetic sorption study of methylene blue (MB) from aqueous solutions. The adsorption of MB on the developed adsorbents (containing Fe3O4, ZnSe, and starch) was examined in a batch system. Characterization of the prepared acrylic adsorbents was performed by UV, FT-IR, SEM and XRD analyzes. The results showed that the four hydrogels could efficiently remove MB from solutions. The residual concentration of MB was analyzed by UV–Vis spectrophotometry at 662 nm (λmax). First the calibration curve of methylene blue dyes was obtained. Then the UV spectrum was taken from the mixture of gel and methylene blue at different concentrations (78,125, 13,950 and 19,531 ppm) and different time intervals (0–10 min) and the graph of the adsorption changes was obtained for each one. These graphs showed the kinetics of adsorption and showed this fact that the adsorption process has followed the Langmuir isotherm (the adsorption values qmax of 42 mg.g−1), and in some cases the Freundlich model. Among the kinetic models applied, the pseudo-second-order (k about 0.3 M−1.min−1) kinetic model was identified with the highest regression coefficients (the first in the high concentrations and the second in the low concentrations). A proposed adsorption mechanism to acrylic hydrogel was illustrated based on the chemical structure of MB and related hydrogel. The stability and reusability of hydrogels and the recovery of absorbed pollutants are among the advantages of this method which shows its economic efficiency. [ABSTRACT FROM AUTHOR]

Slug pellets contain metaldehyde, a potent substance that kills molluscs, which also harms the environment and human health by polluting water systems. Metaldehyde removal from wastewater has emerged as a possible treatment strategy utilizing activated carbon materials such as powdered activated carbon (PAC) and granular activated carbon (GAC). This study aims to compare and analyze the adsorption mechanisms and kinetics of these materials. SEM studies of PAC and GAC revealed unique morphological characteristics, with PAC having a finely textured surface and a well‐defined porosity structure, and GAC having a granular structure with irregularly shaped particles. According to the BET analysis, PAC had a larger surface area and pore volume than GAC, which had a lower surface area and pore volume. The FTIR spectra of PAC and GAC samples reveal different types of bonds such as ―OH, O―H, C―H, C═O, C═C, and C―O which potentially affect their reactivity and interaction with metaldehyde. PAC performed better than GAC in removing metaldehyde from water, as it had a higher surface area and a wider range of pore sizes. The Langmuir isotherm and the pseudo‐second‐order kinetic model fit the experimental data well for this adsorption study. [ABSTRACT FROM AUTHOR]

The bentonite clay has been activated by acid treatment and utilized as a lower‐cost and eco‐friendly adsorbent required to remove Fast Green FCF dye from the aqueous solution. At first acid activated bentonite clay minerals were analyzed by various analytical techniques like Fourier Transform Infrared Spectroscopy (FTIR), x‐ray diffraction (XRD), and x‐ray fluorescence (XRF) analysis. The batch adsorption research was performed to investigate the Fast Green FCF dye adsorption onto the acid‐treated (Bent) bentonite clay. Sorption studies investigated the impacts of adsorbent dosage, initial pH, and time of contact on Fast Green FCF color elimination. The adsorption capacity decreased as the pH was above 7 and then remained almost the same after a pH value of 9. At acidic conditions (below pH value 7), the capacity of adsorption diminished by a decrease in the pH of the solution. The results indicated that the maximum capacity of adsorption has been obtained at an adsorbent dosage of 0.1 g. As the dosage of the adsorbent was improved, several active sites that were available at the time of the dye adsorption increased. As a result, the dye percentage that was removed from the clay increased. Besides these, adsorption kinetics, adsorption equilibrium isotherm, and thermodynamics studies have been also conducted. While studying the adsorption kinetics pseudo‐2nd‐order kinetics has been seen to be more appropriate as compared to pseudo‐1st‐order model. The experimental findings indicated that the attachment of the dye to the clay surface followed the "Langmuir adsorption" isotherm rather than the Freundlich adsorption isotherm with a monolayer coverage of 18.93 mg/g. From the thermodynamics study, it was revealed that the process of adsorption takes place instantly at high temperatures. [ABSTRACT FROM AUTHOR]

Extensive use of dyes by the textile industries poses a serious threat to the aquatic flora and fauna. Low‐cost bio‐sorbent derived from marine red, Gracilaria verrucosa (RAC), and green macroalgae, Enteromorpha intestinalis (GAC) have been used for effective removal of unsafe Malachite Green (MG) dye. Batch study was conducted to determine the different bio‐sorption parameters such as biochar dosage, pH, initial concentration of MG, and contact time including MG bio‐sorption capacities. The physicochemical characterization results show the presence of lower crystallite sizes, and active functional groups such as carbonyl, hydroxyl, carboxyl, sulfate and amine with the mesoporous morphology of the algal biochar. The FT‐IR, XRD and SEM analyses were also performed to characterize the structural investigation of adsorbents. The kinetics of adsorption such as pseudo‐first‐order and pseudo‐second‐order were analyzed and pseudo‐second‐order confirms about the nature of process to be chemisorption. The bio‐sorption test for 20 mg/L of initial MG at an equilibrium time of 90 min by RAC showed maximum removal efficiency of about 97.49% at pH 8 whereas GAC showed a removal efficiency of 93.37% at pH10. Thus, marine macroalgae RAC and GAC can be a substitute for the commercially available adsorbents for degradation of dyes from textile effluents. [ABSTRACT FROM AUTHOR]

At present, developing countries, including Ethiopia, are undergoing a phase of industrial transformation. As a result, there has been a significant rise in the presence of harmful pollutants in groundwater. The release of deleterious heavy metals, such as Cr (VI), into the surrounding ecosystem is a result of various industrial operations. The present investigation utilized activated sodium bentonite clay as an adsorbent agent to facilitate the elimination of Cr (VI). The clay was subjected to acidification and thermal modification techniques to enhance its adsorption capacity. The investigation involved an examination of the particular surface area, capacity for cation exchange, crystalline properties, functional groups on the surface, and structural morphology. The methylene blue test method was employed to ascertain the maximum specific surface area and cation exchange capacity of the adsorbent, which were found to be 512 m2/g and 65.5 meq/100 g, respectively. The clay mineral composition was analyzed using X‐ray diffraction, which indicated that the primary constituent was montmorillonite. The presence of impurities such as quartz, feldspar, muscovite, cristobalite, and hematite was also detected. The study employed response surface methodology, Box–Benkhen design (RSM‐BBD) to investigate the impact of operational parameters, including agitation time, initial Cr (VI) concentration, and adsorbent dosage. Under the optimal conditions, a removal efficiency of 98.05% was achieved for Cr (VI) for a contact duration of 120 min, a dosage of 3.913 g/L, and an initial concentration of 50 mg/L. The sodium bentonite clay that was activated demonstrated a maximum capacity for adsorption of 22.72 mg/g in regards to the adsorption of Cr (VI). The experimental data were best fitted by the Langmuir isotherm, which exhibited a correlation coefficient of 0.9699. The adsorption kinetics were assessed and determined to adhere to a pseudo‐second‐order pattern, exhibiting a coefficient of determination (R2) value of 0.999. Furthermore, the activated sodium bentonite clay demonstrated remarkable potential for repeated utilization in the adsorption of Cr (VI) ions in aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, sugarcane bagasse ash (SCBA), obtained as residue from the sugar mill, was used as an adsorbent for Acid Red 27 (AR27) removal from aqueous solutions. The ash characterization data showed 23.63% of organic compounds and silica (α-SiO2) as the most expressive inorganic compound (confirmed by X-ray diffractogram), the BET surface area had a value of 62.79 m2.g−1 and the pHpzc was 8.45. Regarding the adsorptive tests, the optimal initial pH to the dye removal was 2.0. The adsorption equilibrium reached in about 4 h contact time and optimum SCBA dosage was found to be 4 g.L−1. The pseudo-second order model best represented the adsorption kinetics. The Freundlich equation presented the best fit to the equilibrium data for the removal of AR27 by ash, with maximum adsorption capacity of 15 mg.g−1 at pH 2.0. Thermodynamic study indicate that AR27 adsorption on SCBA occurs through a physisorption mechanism, with ΔHºads < 15 kJ.mol−1. The ΔHºads evaluated by Vant' Hoff equation was explained as a combination of water desorption enthalpy, ΔHºW and isosteric like enthalpy, ΔHºD for the dye adsorption in liquid environment. The ΔHºD = 9.2 kJ.mol−1 was calculated from Clausius-Clapeyron approach. The effects of coexisting anions on the adsorption and regeneration and reuse of the adsorbent were also investigated. This study suggests that SCBA, which was used without any pretreatment, has the potential to be applied as a low-cost adsorbent to mitigate effluents contamination with AR27 dye at low concentrations. [ABSTRACT FROM AUTHOR]

The removal of dyes from effluents of textile industries represents a technological challenge, due to their significant environmental impact. The application of halloysite (Hal) and palygorskite (Pal) clay minerals as adsorbents for the removal of Congo red (CR) and methylene blue (MB) was evaluated in this work. The materials were applied both in natural and acid-treated forms, and characterized by XRD, XPS, SEM–EDS, FTIR, and N2 adsorption–desorption isotherm techniques to identify their properties and main active sites. The adsorbents showed potential to remove CR (> 98%) and MB (> 85%) within 180 min, using 0.3 g adsorbent and initial dye concentration of 250 mg L−1. Semi-empirical quantum mechanical calculations (SQM) confirmed the interaction mechanism between dyes and the adsorbents via chemisorption (− 69.0 kcal mol−1 < Eads < − 28.8 kcal mol−1), which was further observed experimentally due to the high fit of adsorption data to pseudo-second order kinetic model (R2 > 0.99) and Langmuir isotherm (R2 > 0.98). The use of Pal and Hal to remove dyes was proven to be economically and environmentally viable for industrial application. [ABSTRACT FROM AUTHOR]

Nano-biocomposite hydrogel samples were produced using graphene oxide (GO) and agar and applied as adsorbents of organic components in water. The hydrogels were prepared by varying the wt% of Agar and GO. The samples were characterized, and batch adsorption experiments evaluated the effect of initial pH, equilibrium isotherms, and kinetics for the adsorption of the anionic dye Acid Orange 7 (AO) and the cationic dyes Nile Blue A (NB) and methylene blue (MB) in an aqueous medium. Overall, both hydrogel samples exhibited satisfactory results for removing NB and MB; however, there was no effective removal for the anionic dye AO. Adsorption equilibrium isotherms were obtained, and Freundlich, Langmuir, and Sips models were fitted to the experimental equilibrium data; moreover, kinetic data were adjusted to driving force models and particle mass balance. The maximum experimental adsorption capacities, 141.48 mg·g−1 (MB) and 284.69 mg·g−1 (NB), were obtained, on a dry basis, for the sample produced with 70 wt% of agar and 30 wt% of GO. Both hydrogels exhibited remarkable regenerative potential for NB and MB, with the adsorption capacity remaining constant, even after five adsorption/desorption cycles. [ABSTRACT FROM AUTHOR]

Tingui biochar (TB) activated with potassium hydroxide (TB-KOH) was synthesized in the present study. The adsorption capacity of TB-KOH was evaluated for the removal of acetaminophen and caffeine in monocomponent and bicomponent solutions. As a result, the study of the TB-KOH characterization as well as the adsorption kinetics, isotherm, thermodynamics, and a suggestion of the global adsorption mechanism are presented. TB-KOH was characterized through physical–chemical analysis to understand its surface morphology and how it contributes to the adsorption of these drugs. Furthermore, modelling using advanced statistical physical models was performed to describe how acetaminophen and caffeine molecules are adsorbed in the active sites of TB-KOH. Through the characterizations, it was observed that the activation with KOH contributed to the development of porosity and functional groups (-OH, C-O, and C = O) on the surface of TB. The monocomponent adsorption equilibrium was reached in 90 min with a maximum adsorption capacity of 424.7 and 350.8 mg g−1 for acetaminophen and caffeine, respectively. For the bicomponent solution adsorption, the maximum adsorption capacity was 199.4 and 297.5 mg g−1 for acetaminophen and caffeine, respectively. The isotherm data was best fitted to the Sips model, and the thermodynamic study indicated that acetaminophen removal was endothermic, while caffeine removal was exothermic. The mechanism of adsorption of acetaminophen and caffeine by TB-KOH was described by the involvement of hydrogen bonds and π-π interactions between the surface of TB-KOH and the molecules of the contaminants. [ABSTRACT FROM AUTHOR]

In this study, silica sorbents obtained from paddy waste ash were functionalized with (3-Aminopropyl) trimethoxysilane (APTMS) and 3-Glycidyloxypropyl) trimethoxysilane (GPTMS), and used in the adsorption of Remazol Turquoise GN (RTGN) dye in a batch system. The effects of pH (2–8) and the concentration of dye (20–100 mg/L) on the dye removal were investigated. To explain the adsorption mechanism, Langmuir, Freundlich, Temkin and Henry adsorption isotherm models were used. The Langmuir model for Si-APTMS and the Henry model for Si-GPTMS were found to be in agreement with the experimental data. Pseudo first and second-order kinetic models were used for the investigating the adsorption kinetics. It was seen that the adsorption process with Si-APTMS and Si-GPTMS was expressed by Pseudo second-order kinetic model. The dye removal capacities of these sorbents were obtained as 273.87 and 27.51 mg/g, respectively. The dye adsorption behavior of the modified silica sorbents was confirmed by Thermogravimetric (TG), Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyzes. The higher dye removal ability of Si-APTMS sorbent was correlated with the amine functionality of this sorbent. According to the analysis results and proposed adsorption mechanism, it was determined that the electrostatic interaction between the charged -NH3+ in the sorbent surface and the -SO3− groups in anionic dye molecule was mainly responsible for the adsorption process. [ABSTRACT FROM AUTHOR]

Nano-attapulgite (ATP) is a layered silicate mineral with abundant reserves, large specific surface area, and low cost. The unique structure of ATP has attracted wide attention in the field of adsorption. In this study, a preparation technology of ATP grafting basalt fiber (BF) was proposed by chemical grafting method based on the idea of plant root bionics. The optimal preparation process of ATP grafting BF was determined through the tests of asphalt absorption performance, thermal stability performance, and segregation dispersion performance. The mechanism of ATP grafting BF was analyzed by micro-morphology, functional group changes, and elemental composition. Finally, the adsorption performance of ATP grafting BF was investigated on the basis of adsorption kinetics model and molecular dynamics simulation. The study results indicated that ATP-BFHCl had better compatibility and wettability with asphalt. The quasi-second-order kinetic equation could better fit the adsorption process of ATP-BFHCl on asphaltene, which indicated that ATP-BFHCl adsorbed asphaltene with chemisorption or ion exchange. The diffusion coefficient and diffusion activation energy of the saturate and the aromatic were larger, indicating a smaller molecular weight and faster movement, and lightweight components of asphalt are more easily adsorbed on the surface of ATP. The diffusion activation energy of asphaltene is the smallest and the reaction is the easiest to take place, which indicates that it is the first to react during temperature increase. The research results can provide a theoretical basis and technical support for BF surface treatment technology. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) is a polymer structurally like plant cellulose, but with superior physicochemical properties. BC and the several functionalization possibilities exhibited by cellulosic polymers have led to new versatile multifunctional materials. Several studies have investigated modifications to the BC surface to make it effective, for example, in antibacterial and adsorption terms, so, BC was functionalized with the silanes 3-Aminopropyltriethoxysilane and 3-glycidyloxypropyltrimethoxysilane in three different proportions. Although the diffractograms of the modified samples did not exhibit significant changes, this indicates FTIR spectra, with primary amino groups and stretching the vibration of Si–O–Si. Regarding drug adsorption kinetics, the samples exhibited a better fit with the pseudo-second-order model the increase in pH value promoted an increase in the maximum amount of adsorption, with values of q = 98.92 mg g−1 for Ibuprofen and q = 98.50 mg g−1 for Ketoprofen. In the in vitro release tests using gastric fluid, the release rate achieved higher values compared to PBS environments. The highest release values were observed with the samples modified by method 2 and particularly, the BC70-A sample showed the highest percentage of drug release. Controlled release can provide a smoother and prolonged release profile, resulting in a more stable response to the medication. Silanized BC showed greater inhibition for Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

BACKGROUND: To investigate the recovery of molybdate from water and hydrodesulfurization catalysts, a novel synthesized phosphonate Schiff base, 4,4′‐(((2,2‐dimethylpropane‐1,3‐diyl) bis(azaneylylidene)) bis(methaneylylidene)) bis(2‐methoxyphenol) (HMI) and 4‐(((3‐((4‐(((S)‐hydroxyhydrophosphoryl)oxy)‐3‐methoxybenzylidene) amino)‐2,2‐dimethylpropyl)imino)methyl)‐2‐methoxyphenyl hydrogen phosphonate (HIMP), was utilized. This study aimed to assess the structural and property aspects of this synthesized compound using diverse characterizations, including FTIR, Thermogravimetric Analysis (TGA), mass spectrometry (GC–MS), fluorescence transfer spectra, scanning electron microscopy (SEM), and 1H‐NMR, 13C‐NMR, and 31P‐NMR. RESULTS: The study systematically examined several factors controlling molybdate recovery, including temperature, adsorbent dosage, pH, interaction time, and molybdate concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 2, with an interaction time of 40 min, a 0.06 g adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (Qe) of 372.54 mg of Mo per gram, with empirical data fitting the Langmuir and D‐R adsorption models. The kinetics of molybdate uptake followed second‐order kinetics. Thermodynamic aspects, including ΔG°, ΔS°, and ΔH°, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Additionally, molybdate adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified phosphonate Schiff base for molybdate removal. CONCLUSION: The study underscores the potential of the modified phosphonate Schiff base as a crucial adsorbent for molybdate elimination from both solutions and spent hydrodesulfurization catalysts. The findings offer important insights into the adsorption kinetics, thermodynamics, and selectivity of the adsorbent, enhancing our understanding of molybdate recovery processes and their broader applications. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

AbstractThe performance capability of granular activated carbon (GAC) adsorption in terms of disinfection by-product (DBPs) removal was investigated with synthetic water containing 1) trihalomethanes (THMs), 2) haloacetronitriles (HANs), and 3) Mix-THMs & HANs. The initial 20 min of adsorption resulted in the maximum adsorption rate, with the total THMs, total HANs, and total Mix–THMs & HANs being 4.972, 2.071, and 6.460 µg/gGAC-min, respectively. GAC dosage affects the adsorption selectivity of THMs and HANs. Under a low GAC dosage, the selectivity of GAC adsorbs more bromo-THMs than chloro-THMs. The adsorption selectivity of THMs on GAC following bromoform > dibromochloromethane > bromodichloromethane > chloroform was investigated. As the GAC concentration increased, the selectivity of THM adsorption by GAC became comparable. Chloro-HAN, in contrast to THMs, has a higher adsorption selectivity than bromo-HAN. Trichloroacetonitrile was removed by GAC more rapidly than the other HAN species when the GAC dose was increased. The toxin of bromoform was primarily eliminated through GAC adsorption, caused by a greater removal rate than that of the other THMs. As an implemented measure, GAC is introduced to reduce THMs and HANs and the toxic contents associated with THMs and HANs. [ABSTRACT FROM AUTHOR]

The development of in situ techniques to quantitatively characterize the heterogeneous reactions is essential for understanding physicochemical processes in aqueous phase. In this work, a new approach coupling in situ UV–vis spectroscopy with a two‐step algorithm strategy is developed to quantitatively monitor heterogeneous reactions in a compact closed‐loop incorporation. The algorithm involves the inverse adding‐doubling method for light scattering correction and the multivariate curve resolution‐alternating least squares (MCR‐ALS) method for spectral deconvolution. Innovatively, theoretical spectral simulations are employed to connect MCR‐ALS solutions with chemical molecular structural evolution without prior information for reference spectra. As a model case study, the aqueous adsorption kinetics of bisphenol A onto polyamide microparticles are successfully quantified in a one‐step UV–vis spectroscopic measurement. The practical applicability of this approach is confirmed by rapidly screening a superior adsorbent from commercial materials for antibiotic wastewater adsorption treatment. The demonstrated capabilities are expected to extend beyond monitoring adsorption systems to other heterogeneous reactions, significantly advancing UV–vis spectroscopic techniques toward practical integration into automated experimental platforms for probing aqueous chemical processes and beyond. [ABSTRACT FROM AUTHOR]

To address ciprofloxacin's (CPF) persistent presence in water and potential ecological and health hazard, the challenge is to develop an effective method for its removal from wastewater. This work is aimed at optimizing the adsorptive removal of ciprofloxacin (CPF) utilizing a layered double hydroxide pine cone biochar composite (LDH/PCBC). Response surface methodology (RSM) is employed to design the experiments to obtain optimal experimental conditions for improved adsorption processes. The CPF removal efficiency of LDH/PCBC from aqueous solution is found to be 97.6% under the optimized conditions (pH = 7, adsorbent dose = 0.45 g L−1, initial CPF concentration = 52 mg L−1 and temperature = 303 K). The Freundlich isotherm confirms the best fit, and the Langmuir adsorption capacity of the LDH/PCBC is determined to be 476.2 mg g−1 at 303 K. The pseudo-second-order model fitted the best for adsorption kinetics, suggesting that the adsorption process is directed by chemisorption. The thermodynamic investigation confirmed the endothermic and spontaneous adsorption process (ΔH° = 56.9 kJ and ΔG° from −3.2 kJ at 278 K to −10.8 kJ at 318 K). The study reveals that LDH/PCBC can be reused effectively with insignificant loss of removal efficiency (∼6%). The cost of the development and large-scale application of LDH/PCBC for the removal of CPF is $988.75 per ton. The results indicate that the LDH/PCBC outperforms the reported adsorbents for sustainable removal of CPF from aqueous solutions. This is the first report on the use of LDH/PCBC as a cheaper and environment friendly method for the removal of CPF from water. [ABSTRACT FROM AUTHOR]

Abstract\nNovelty statementThe article details a feasibility study of removing Brilliant Green (BG), a mutagenic dye from an aqueous solution by adsorption using low-cost coriander seed spent as a by-product in the nutraceutical industry. The study includes an analysis of the parameters that affect the adsorption process. The variables that have been identified include pH, dye concentration, process temperature, adsorbent amount, and particle size of the adsorbent. To obtain information on the adsorption process and to design the mechanism of the adsorption system on experimental equilibrium, 10 isotherm models, namely, Langmuir, Freundlich, Jovanovic, Dubinin–Radushkevich, Sips, Redlich–Peterson, Toth, Vieth–Sladek, Brouers–Sotolongo, and Radke–Prausnitz were applied. It was discovered that the experimental adsorption capacity, qe, was roughly 110 mg g−1. The result has a maximum adsorption of 136.17 mg g−1 as predicted by Dubinin–Radushkevich isotherm. Diffusion film models, Dumwald–Wagner and Weber–Morris models, and pseudo-first- and second-order models, were used to determine the adsorption kinetics. It was realized that the adsorption kinetics data fit into a pseudo-second-order model. Thermodynamic analysis with a reduced enthalpy change suggests a physical process. The values of the thermodynamic parameters ΔG0, ΔH0, and ΔS0 demonstrated an endothermic and nearly spontaneous process of adsorption. The small valuation of ΔH0 specifies that the process is physical. FTIR spectroscopy and SEM imaging were used to confirm that the BG dye had been adsorbing on the adsorbent surface. The study concludes that NICSS is an effective adsorbent to extract BG dye from wastewater solutions, offers insights into numerous dye and adsorbent interaction possibilities and indicates that the process can be scaled to fit into the concept of circular economy.An attempt has been made to link the concept of circular economy through design and execution of the experiments in the laboratory scale. The following highlights will justify the newer approach adopted by the authors.The experiments are designed by intention to suit the concept of circular economy.The use of NICSS, a nutraceutical industrial spent, which has no feed, fertilizer, or fuel value suits the sustainability concept.The reuse of “waste” from the remediation process replaces the “end-of-life” concept in circular economy.An attempt has been made to link the concept of circular economy through design and execution of the experiments in the laboratory scale. The following highlights will justify the newer approach adopted by the authors.The experiments are designed by intention to suit the concept of circular economy.The use of NICSS, a nutraceutical industrial spent, which has no feed, fertilizer, or fuel value suits the sustainability concept.The reuse of “waste” from the remediation process replaces the “end-of-life” concept in circular economy. [ABSTRACT FROM AUTHOR]

Ciprofloxacin (CIP) is the commonly prescribed fluoroquinolone antibiotic and one of the top ten emerging pharmaceutical contaminants in the world. It can pose a potential health risk if its residues enter the body. In this study, the adsorption of CIP onto magnetic iron oxide nanoparticles coated with silver (Fe3O4@AgNPs) was evaluated. Fe3O4@AgNPs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X‐ray Diffraction (XRD), and Scanning Electron Microscope (SEM). The parameters affecting the adsorption of CIP on nanoadsorbent were investigated including the adsorbent dose, pH, contact time, the salt content, and mixing speed. The highest efficiency of removal was achieved at pH 6, adsorbent dose of 3 mg l−1, salt content of 1 % (W/V) and shaking rate of 100 rpm. The adsorption process of CIP on the nanoadsorbent followed the Freundlich adsorption isotherm model, the adsorption kinetics was pseudo‐second order and the maximum adsorption capacity was 125 mg g−1. [ABSTRACT FROM AUTHOR]

The design and development of new large-capacity and selective materials for extracting rare precious metals via electronic waste is practically essential. In this paper, a new efficient UiO-66-NCS has been obtained as a consequence of the modification of the classical Zr-MOF (UiO-66-NH2), and its ability to recover gold has been investigated. These batch results adequately illustrated that UiO-66-NCS exhibited good adsorption capacity (675.5 mg g−1) and exceptional selectivity. In addition, UiO-66-NCS achieved faster adsorption equilibrium times of about 120 min. Adsorption kinetics and isotherms demonstrated that the pseudo-second-order adsorption scheme and a Langmuir-type procedure were shown by the adsorption of Au(III) on UiO-66-NCS. Characterized by pH effect experiments, TEM, XRD, and XPS, the adsorption of UiO-66-NCS with Au(III) relies on coordination, which further results in reduction, and the generated Au(0) is uniformly dispersed in the MOF. The adsorbent has considerable advantages for cyclic regeneration. Finally, DFT fitting results showed that the adsorption binding energy of UiO-66-NCS with [AuCl4]− was −8.63 kcal mol−1 for the adsorption process. UiO-66-NCS is likely to be an ideal substance for gold recovery. [ABSTRACT FROM AUTHOR]

In the current work, the adsorption of acid black 1 (AB1), a hair dye, and methyl orange (MO) on anion exchange membrane BII (AEM-BII) in a binary system was studied experimentally. The effects study for contact time, adsorbent's and adsorbates' concentration, and temperature of aqueous media on the AB1 and MO removal, AEM-BII recovery, and reusability were also investigated. The highest removal was observed at optimum conditions, 150-min contact time and 5 g L−1 of adsorbent for AB1 (91.2%) and MO (83.4%). Adsorption kinetics was estimated by pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetics. The experimental findings were fitted well by PSO kinetics with an adsorption capacity of 19.45 ± 0.93 and 19.34 ± 0.84 mg g−1 for ABI and MO, respectively. Moreover, the adsorption isotherm study confirmed that AB1 and MO adsorption by AEM-BII from the binary system was followed by Langmuir isotherms. Adsorption thermodynamics revealed that adsorption of both AB1 and MO by AEM-BII was endothermic and spontaneous. Moreover, the desorption phenomenon of ABI and MO from the loaded AEM-BII showed that dye removal from AEM-BII was found to be 74.95%, demonstrating AEM-BII can be considered as good adsorbent for acidic dyes from the binary system. [ABSTRACT FROM AUTHOR]

Hybrid material of surgical mask activated carbon (SMAC) and Fe2O3 (SMAC-Fe2O3) composite was prepared by simple co-precipitation method and used as potential material for the remediation of 2,4-dicholrophenol (2,4-DCP). The XRD patterns exhibited the presence of SMAC and Fe2O3, FTIR spectrum showed the FeO-carbon stretching at the wavenumber from 400 to 550 cm−1. UV–Vis DRS results showed the band gap was 1.97 eV and 2.05 eV for SMAC-Fe2O3 and Fe2O3, respectively. The SEM images revealed that the Fe2O3 doped onto the fiber morphology of SMAC. The outcomes of the BET examination exhibited a surface area of 195 m2/g and a pore volume of 0.2062 cm3/g for the SMAC/Fe2O3 composite. The batch mode study shows the maximum adsorption and photocatalytic degradation efficacies which were 97% and 78%, respectively. The experimental data was studied with both linear and nonlinear adsorption isotherm and kinetics models. The nonlinear Langmuir isotherm and pseudo-second-order kinetics (PSOK) models have well fit compared with other models. The Langmuir maximum adsorption capacity (qmax) was found 161.60 mg/g. Thermodynamic analysis shows that the 2,4-DCP adsorption onto SMAC-Fe2O3 was a spontaneous and exothermic process. The PSOK assumes that the adsorption process was chemisorption. The photocatalytic degradation rate constant of 2,4-DCP was calculated using pseudo-first-order kinetics (PFOK) and the rate constant for SMAC-Fe2O3 and Fe2O3 were 0.859 × 10−2 min−1 and 0.616 × 10−2 min−1, correspondingly. In addition, the obtained composite exhibited good reusability after a few cycles. These results confirmed that SMAC-Fe2O3 composite is an effective adsorbent and photocatalyst for removing 2,4-DCP pollutants. [ABSTRACT FROM AUTHOR]

Chlorophenols are one of the major organic pollutants responsible for the contamination of water bodies. This study explores the application of Ni-Zn/CeO2 nanocomposites, synthesized via the aqueous co-precipitation method, as effective adsorbents for the 4-chlorophenol removal from aqueous solutions. The nanocomposites' chemical and structural characteristics were assessed using different physical characterization methods, viz. X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, using a Box-Behnken design within response surface methodology, optimal conditions of pH 3, temperature 20 °C, contact time 120 min, adsorbent dosage 0.05 g, and 4-chlorophenol concentration 50 ppm are identified. Among the nanocomposites tested, NZC 20:10:70, with 20% Ni and 10% Zn, achieves enhanced performance, removing 99.1% of 4-chlorophenol within 2 h. Adsorption kinetics follow the pseudo-second-order model and equilibrium data fit the Freundlich isotherm. Thermodynamic analysis indicates an exothermic and spontaneous process. The adsorption capacity of NZC 20:10:70 shows significant enhancement, growing from 19.85 mg/g at 10 ppm to 96.33 mg/g at 50 ppm initial concentration. Physical characterization confirms NZC 20:10:70's superior properties, including a high surface area of 118.471 m2/g. Evaluating economic viability, NZC 20:10:70 demonstrates robust reusability, retaining 85% efficiency over eight regeneration cycles. These results highlight NZC 20:10:70 as a promising adsorbent for effective and sustainable chlorophenol removal in water treatment. [ABSTRACT FROM AUTHOR]

The selection of adsorbents is critical for developing an adsorption unit. In this study, a activated carbon fibers (ACF) and a granular‐activated carbon (GAC) were evaluated in dynamic toluene adsorption to determine their benefits and limitations. A variety of physicochemical approaches were used to characterize the samples. Adsorption under varied circumstances demonstrated that ACF has a larger adsorption capacity and a longer saturation time than GAC. The Langmuir isotherm suited equilibrium data well. Thermodynamic characteristics showed that adsorption was spontaneous and exothermic. The adsorption kinetics were found to be dominated by the pseudo‐first‐order model, with GAC having a greater sorption rate. Thermal regeneration appeared to be more favorable for ACF. [ABSTRACT FROM AUTHOR]

This study investigates the incorporation of algae-based activated carbon into polyurethane foam to improve a biocomposite for gasoil sorption. The biocomposites were thoroughly analyzed using various techniques to examine the properties of both the blank foam and the algae activated carbon foam with a carbon content of 4.41 mass% and particle diameter of 500 µm. These techniques included Scanning Electron Microscopy (SEM), thermogravimetric analysis (TGA), and density analysis. The TGA analysis revealed that the biocomposites had an impact on the onset temperature (Tonset) of the foams. Higher concentrations of the biocomposites resulted in a decrease in Tonset from approximately 310 °C in the blank foam (PUF0) to 300 °C in the composite (PUF3B). The final residue percentage also decreased from around 20% in PUF0 to 10% in PUF3B. Density analysis showed that the apparent density of the foam increased from 0.016 g/cm3 in the blank foam to 0.020 g/cm3 in the biocomposite (PUF3B), while the real density slightly decreased from 0.092 g/cm3 to 0.076 g/cm3, indicating a reduction in overall porosity from 82.5% to 74.4%. All foams that were modified showed an increase in their ability to absorb gasoil in a PUF/gasoil/water system. The optimized biocomposite (PUF1B), with 1.14 mass% of 500 µm algae carbon, displayed the highest sorption capacity, starting at approximately 50 g/g at 1.5 h and increasing to 53 g/g over 72 h. The analysis of adsorption kinetics revealed that by utilizing adsorption isotherms, particularly the Langmuir isotherm, a more accurate fit to the data was achieved. This allowed for the prediction of the maximum gasoil adsorption capacity. This study aims to further develop, analyze, and utilize biocomposites made from algae-based activated carbon and polyurethane. These materials offer a sustainable and environmentally friendly approach to cleaning up oil spills. [ABSTRACT FROM AUTHOR]

The expansion of vermiculite using microwave irradiation is an environmentally friendly and efficient method that can enhance the material's adsorption performance. This study investigated the microwave irradiation of vermiculite with five different particle sizes (4/2/1/0.5/0.2 mm) and found that the adsorption capacity for Pb2+ increased with larger particle sizes. The equilibrium adsorption capacity reached 15.98 mg/g at 4 mm, representing a 45.01% improvement compared to 0.2 mm. The pseudo-second-order kinetic model effectively described the adsorption kinetics. No significant differences were observed in the specific surface area and pore size distribution of all samples. Thermogravimetric quantitative analysis revealed that larger particle sizes retained interlayer water more effectively. As the particle size decreased, the interlayer water content generally showed a decreasing trend. Fourier-transform infrared spectroscopy analysis also indicated that the -OH groups in larger particle sizes exhibited higher stability. The results suggest that the high content and stability of -OH groups may be key factors in the enhanced adsorption performance for Pb2+. This provides new insights for the preparation of environmentally friendly adsorbent materials rich in hydroxyl groups. [ABSTRACT FROM AUTHOR]

The effective recovery of gallium from wastewater discharge in the Bayer process is promising for the long-term development of gallium resources. The adsorption and desorption behavior of gallium (Ga), vanadium (V), and aluminum (Al) ions on a strong acidic styrene cation exchange resin (JK resin) from a simulated Bayer solution was systematically investigated by static experiments. The results showed that the optimum conditions for separating Ga from V and Al were at low temperatures and short contact times, with 78.30%, 15.16%, and 6.63% of the adsorption efficiency at 25 °C and 60 min, respectively, for Ga, V, and Al. The adsorption kinetics of Ga3+ conformed to the pseudo-second order model, and the static saturation adsorption capacity was 18.25 mg/g. The Langmuir model fitted the adsorption isotherm of gallium well, and the maximum adsorption capacity was 1.11 mg/g at 25 °C. FT-IR spectroscopy and XPS showed that the mechanism of the Ga3+ adsorption was only related to the interaction of the oxygen atoms of the amide oxime group (C=NOH). The separation of Ga, V, and Al can be achieved by desorbing 98% of Al with low concentrations of ammonia and 90% of Ga with low concentrations of hydrochloric acid. The results indicate that JK resin is an efficient adsorbent for separating gallium and vanadium in alkaline solutions. [ABSTRACT FROM AUTHOR]

Three new nonporous mercury(II) coordination polymers (CPs) containing the ditopic 1,1′-(1,4-phenylene)bis(3-(pyridin-4-yl)urea) ligand (4,4-pbubp), namely, {[Hg(4,4-pbubp)Cl2](DMSO)3}n (CP1), {[Hg(4,4-pbubp)Br2](DMSO)3}n (CP2) and {[Hg(4,4-pbubp)I2](DMSO)4}n (CP3) were synthesized and characterized structurally through infrared analysis, elemental analysis (CHNS), TGA, PXRD and single-crystal X-ray diffraction analysis. All of these compounds formed 1D polymeric zigzag chains self-assembled in the crystal into higher-dimensional structures through various hydrogen-bonding interactions involving the urea functional group and several DMSO solvent molecules. These CPs were examined as potential adsorbents for the reversible uptake of iodine from the solution. Theoretical analysis of the adsorption kinetics and isotherms was applied to examine the iodine adsorption data. The results correlated effectively with the pseudo-second-order kinetic model and the Freundlich isotherm model. Our results showed that in this family, the iodine uptake capacity was dependent on the anion (CP1 > CP2 > CP3), and the compound which contained chloride anions (CP1) showed the highest capacity to remove iodine. The maximum uptake capacity of 262.01 mg g−1 iodine over CP1 at room temperature based on the Freundlich model was achieved. After iodine adsorption, compounds@I2 were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) as well as Raman spectroscopy. [ABSTRACT FROM AUTHOR]

The adsorption of l-tryptophan (l-Trp) was studied based on the hydrophobic interaction/ion exchange/ion exclusion mixed-mode adsorption resin D301. Firstly, the interaction mode between l-Trp and resin was analyzed by studying the influence of pH variation on the adsorption capability and the dissociation state of l-Trp. Secondly, the adsorption mechanism was illuminated by studying the adsorption equilibrium and kinetic behaviors. The adsorption equilibrium and a kinetics model were constructed. The augmentation of pH gradually elicited an enhancement in the adsorption capacity of l-Trp. l-Trp existing in varied dissociation states could be adsorbed by the resin, and the interaction mode relied upon the pH of the solution. An integrated adsorption equilibrium model with the coadsorption of different dissociation states of l-Trp was developed and could predict the adsorption isotherms at various pH levels satisfactorily. Both external mass transfer and intra-particle diffusion collectively imposed constraints on the mass transfer process of l-Trp onto the resin. An improved liquid film linear driving force model (ILM) was constructed, and the model provided a satisfactory fit for the adsorption kinetics curves of l-Trp at various pH levels. l-Trp molecules had a high mass transfer rate at a relatively low solution pH. [ABSTRACT FROM AUTHOR]

A polyvinylimidazole-based cryogel is presented as a pioneering solution for efficient extraction and release of partially water-soluble polyphenols from olive byproducts. Specifically, oleuropein was used as model molecule to evaluate its recovery from water. The material merges the properties of interconnected cryogel structure in adsorbing molecules via fast diffusion flux, with the strong electrostatic interactions acted by imidazole moiety. Such cryogel achieves effective oleuropein binding likely through hydrogen bonding and π–π interactions. Comprehensive assessments of static adsorption kinetics, isotherms, and desorption kinetics underscore the cryogel's efficacy in oleuropein extraction and release, highlighting its pivotal role in valorizing olive wastewater through sustainable biotechnological applications. [ABSTRACT FROM AUTHOR]

Integration of more thermodynamically favorable valorization of biomass (e.g., glycerol), compared to sluggish oxygen evolution, with H2 production is of great significance for energy‐saving electrosynthesis of value‐added chemicals. However, its widespread deployment has been challenged by costly electrocatalysts and large overpotential reaching an industrial‐relevant current density (≥400 mA cm−2). Herein, carbon shell‐encapsulated manganese‐doped cobalt nitride nanoarrays immobilizing on nickel foam, denoted Mn‐CoN@C/NF, are crafted via hydrothermal method and ammoniation. As a bifunctional electrocatalyst, the Mn‐CoN@C/NF manifests extraordinary activity for glycerol oxidation reaction (GOR) with an ultralow potential of 1.37 V (versus RHE) at 400 mA cm−2, in conjunction with H2 evolution reaction (HER) with a low overpotential of 31 mV at 10 mA cm−2. A record high Faradaic efficiency (97.7%) for formate production of GOR is delivered at 1.35 V (vs RHE). Impressively, a two‐electrode electrolyzer capitalizing on the Mn‐CoN@C/NF as catalysts reaches 800 mA cm−2 at 1.83 V, delivering an electricity‐saving efficiency of 15.0% compared to pure water splitting. DFT calculations substantiate that Mn species within Mn‐CoN not only optimize hydrogen adsorption kinetics for HER, but also elevate Co3+ active sites' density for GOR. This work offers an energy‐saving and efficient electrosynthesis avenue for coproduction of valuable chemicals. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSRemoval of dyes has been a matter of great interest for researchers because of health and toxicity issues. In this research work, green biochar was produced using precipitation technique, and by the adsorption process, it was supported on layered double hydroxide (LDH). Biochar/LDH composites were synthesized from Neem, Amaltas, and Keekar stems, eggshells, and Eucalyptus (N, A, K, Egg, and Eu’s biochar/LDH-composite). These composites were employed to remove synthetic dyes from an aqueous solution. Recent studies have identified optimal conditions for LDH-composites under various parameters: pH 9 or 10 with a dosage of 0.05 g/50 mL yields higher adsorption capacities across different LDH composites, ranging from 40.74 to 48.30 mg/g at a reaction time of 90 min using a Pink-XFG dye concentration of 10 ppm, which is favorable. Temperatures of 303–308 K are suitable. Second-order kinetics, along with the Langmuir and Freundlich adsorption isotherms, along with exothermic reactions, presented good-fit results on adsorption kinetics and equilibrium data. The adsorption potential was significantly affected by various concentrations of electrolytes, surfactants, detergents, and heavy metal ions. 0.5 N hydrochloric acid was determined to be the most efficient agent for the process of desorption. These methods are very cost-effective, eco-friendly, and easy to manufacture.Utilizes eco-friendly biochar from natural sources for creating LDH nanocomposites.Establishes precise conditions (pH, temperature, etc.) for maximal dye removal.Demonstrates high capacity for toxic Pink-XFG dye removal from water.Assesses how electrolytes, heavy metals, and detergents affect adsorption efficiency.0.5 N hydrochloric acid is effective for desorption, enabling adsorbent reuse. [ABSTRACT FROM AUTHOR]

Tryptophan (an essential amino acid) and its clinically important metabolite—kynurenine contribute to several fundamental biological processes and methods that allow their determination in biological samples are in demand. The novelty of the work was a demonstration of the utility of two polymers: 4-vinylpyridine crosslinked with trimethylolpropane trimethacrylate (poly(4VP-co-TRIM)) or 1,4-dimethacryloyloxybenzene (poly(4VP-co-14DMB))—in terms of human serum clean-up for simultaneous LC–MS determination of tryptophan and kynurenine. The goal was to achieve a reduction of the matrix effect, which is responsible for signal suppression, with minimal capture of analytes. The adsorption properties of the polymeric beads were studied by evaluating the adsorption kinetics and isotherms in model matrices. Therefore, the adsorption capacities of both molecules were not efficient, the tested 4-vinylpyridine-based copolymers have shown great promise (especially poly(4VP-co-TRIM)) as sorbents for serum clean-up. In the model human serum matrix, poly(4VP-co-TRIM) provided good recoveries of tryptophan and kynurenine (76% and 87%, respectively) and allowed for the reduction of the matrix effect. Performances of both copolymers were compared to those of commercially available sorbents (octadecylsilane, activated charcoal, and primary secondary amine). [ABSTRACT FROM AUTHOR]