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This study focuses on the development of eco-friendly biobased adsorbents through a sustainable hydrothermal and freeze-drying synthesis process, utilizing cost-effective bio-sourced materials to minimize energy consumption and waste. The biobased adsorbents were elaborated using hydroxyethyl cellulose-ionic liquids and bentonite clay. The elaborated biocomposites were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy/attenuated total reflection (FTIR/ATR), thermogravimetric analysis (TGA), and electron microscopy-energy dispersive X-ray (SEM–EDX), Brunauer–Emmett–Teller (BET) and zeta potential (ZP). Structural analysis confirms the intercalation and incorporation of HEC-ILs polymeric chains into Be-Na matrix and the formation of biocomposites. The [HEC-ILs/Be-Na] composite was subsequently employed for solid-phase extraction of Co(II) by investigating the effect of pH, initial Co(II) concentrations, time, temperature, and the presence of co-existing ions (Na(I), Li(I), Mn(II), Ni(II), and Al(III)). The adsorption kinetics of Co(II) metal ions were suitably characterized using the pseudo-second-order model (with R2 > 0.99). Furthermore, the adsorption isotherms conformed to the Langmuir model (with R2 > 0.97), suggesting a chemisorption process with an adsorption capacity of 69.8 mg/g. The thermodynamic study reveals that the adsorption process exhibits characteristics of spontaneity and endothermicity (ΔH° = 74.197 kJ mol−1, ΔG° < 0 kJ mol−1). The proposed mechanism for Co(II) adsorption on the developed biocomposite involves electrostatic interactions, ion exchange, and anion-π interactions. The biobased composite exhibited remarkable selectivity for Co(II) and demonstrated great potential as an adsorbent for industrial applications. [ABSTRACT FROM AUTHOR]

A pH responsive monometallic‐clay nanocomposite hydrogel, sodium alginate‐cl‐poly (N‐hydroxy ethyl acrylamide‐co‐methacrylic acid) @ Au/ montmorillonite clay (SANCHG@Au/MMT) is synthesized in situ using sodium alginate (SA) as a polysaccharide. Two other nano composite hydrogels namely sodium alginate‐cl‐poly (N‐hydroxy ethyl acrylamide‐co‐methacrylic acid) @ Au (SANCHG@Au) and sodium alginate‐cl‐poly (N‐hydroxy ethyl acrylamide‐co‐methacrylic acid) @ montmorillonite clay (SANCHG@MMT) are also prepared. All the synthesized nano composite hydrogels are characterized using various techniques. Water swelling of the three hydrogels along with their textile dye adsorption properties is evaluated in congo red (CR), benzopurpurin (BP) and tartrazine (TZ) from their aqueous solutions. Among the three hydrogels the % water swelling of SANCHG@Au/MMT is superior (396% at pH = 8) and also the adsorption capacity over the other two. The dye adsorption property of SANCHG@Au/MMT is found to be pH sensitive. Adsorption follows both the Langmuir adsorption isotherm with Qmax values 512.19 mg.g−1 for CR at pH = 4, 476.09 mg.g−1 at pH = 4 for BP and 454.79 mg.g−1 at pH = 6 for TZ respectively and Dubinin–Radushkevich isotherm model. The kinetic data fit with pseudo second order kinetic model. Thermodynamic parameters like negative ∆G0 and positive ∆H0 values suggest that the adsorption process is spontaneous and endothermic in nature. [ABSTRACT FROM AUTHOR]

The present study investigated the capability of cassava peel (Manihot Esculenta Crantz) in Pb(II) and Cr(VI) removal. The comparative study was conducted using batch method observing some parameters. The results indicated that the optimum adsorption of Pb(II) occurred at pH 5, initial concentration of 1000 mg/L, and contact time of 50 min. On the other hand, the optimal adsorption of Cr(VI) was achieved at pH 2, initial concentration of 1200 mg/L, and contact time of 70 min. The adsorption isotherms of both metals tended to follow the Langmuir model, while the adsorption kinetics suited to pseudo-second-order model. Thermodynamic parameters indicated that the adsorption process was spontaneous (ΔG° negative), endothermic (ΔH° positive), and exhibited surface dispersion on the biosorbent (ΔS° positive). Characterization using Fourier Transform Infrared (FTIR), X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), and Thermogravimetry (TGA) provided evidence of both physical and chemical adsorption. The adsorption capacity of cassava peel was also tested on samples collected approximately 30 m from the bay shoreline, resulting in a removal percentage of 94.67% for Pb(II) and 82.28% for Cr(VI) under optimal pH and contact time conditions. [ABSTRACT FROM AUTHOR]

This article presents the unique research results of the comprehensive analysis of the porous structure of activated carbons obtained from biomass waste materials from the wood industry during activation in an air atmosphere. The porous structure was analysed on the basis of nitrogen and argon adsorption isotherms via complementary multi-method analysis, i.e. the new numerical clustering-based adsorption analysis, the non-local density functional theory and the quenched solid density functional theory methods. The analytical results for the prepared activated carbons were compared with analogous results obtained for commercial activated carbon. On the basis of the conducted studies it has been determined that the new numerical clustering-based adsorption analysis method gives credible and valuable information on the textural properties of activated carbons which are in strict correlation and mutually complement with the results of the analysis with the use of the quenched solid density functional theory method. The research results obtained in this paper, it has also been shown that from waste materials of the wood industry, in a relatively cheap and cleaner production process, it is possible not only to obtain carbonaceous materials almost comparable to commercial activated carbon, but also to manage the waste in accordance with the principles of a closed-loop economy and sustainable development. The paper pays also attention to the often overlooked economic and ecological aspects, which should nevertheless be taken into account when comparing different adsorbents, rather than their textural properties alone. [ABSTRACT FROM AUTHOR]

In this study, metal-doped quaternary nano ferrites (Co0.5Zn0.25M0.25Fe2O4, M = Ba, Cu, Mn, Ni and Sr) were synthesized and evaluated for their efficiency in removing Direct Orange-108 Acid Dye from aqueous solutions. The adsorption performance of these materials was systematically investigated under various conditions. Optimal pH levels for dye removal were found to be pH 2 (41.45 mg/g), pH 2 (36.37 mg/g mg/g), pH 4 (31.13 mg/g), pH 4 (44.75 mg/g), and pH and 3 (39.62 mg/g) at optimal dosage of 0.05 g/50 mL and at an initial concentration of at 75 ppm and 50 ppm for Co0.5Zn0.25Ba0.25Fe2O4, Co0.5Zn0.25Cu0.25Fe2O4, Co0.5Zn0.25Mn0.25Fe2O4, Co0.5Zn0.25Ni0.25Fe2O4 and Co0.5Zn0.25Sr0.25Fe2O4 respectively. Additionally, the study revealed that an optimum temperature of 40 °C enhanced the adsorption efficiency, resulting in adsorption capacities of 41.92 mg/g, 40.56 mg/g, 33.22 mg/g, 48.00 mg/g, and 43.71 mg/g for Co0.5Zn0.25Ba0.25Fe2O4, Co0.5Zn0.25Cu0.25Fe2O4, Co0.5Zn0.25Mn0.25Fe2O4, Co0.5Zn0.25Ni0.25Fe2O4 and Co0.5Zn0.25Sr0.25Fe2O4 respectively. The shaking time with optimal results were obtained at 45 and 60 min. Similarly, as a photocatalyst have optimal pH at 2, 3 and 4, optimum dose 0.05 g/50 mL, initial concentration of dye was 50 and 75 ppm with contact time of 45 and 60 minutes at 40 °C as optimum temperature. The pseudo second order adsorption kinetic model and Langmuir adsorption equilibrium isotherm displayed strong fitting for experimental data. While degradation kinetic follow BMG and second kinetic model. NH4OH solution showed maximum desorption The thermodynamic study demonstrated the exothermic character. The adsorption study of real textile effluents was also conducted that yielded valuable information. Highlights: Novel metal doped quaternary nano ferrites Co0.5Zn0.25M0.25Fe2O4 (M = Ba, Cu, Mn, Ni and Sr) were synthesized, characterized, and used for dye adsorption. Langmuir adsorption isotherm and pseudo second order kinetic model fitted best and proved most appropriate for this study. The size, changeable properties and shape are the most notable characteristics of nano ferrites, therefore the use of ferrites in many applications is enhancing day by day. [ABSTRACT FROM AUTHOR]

In this study, we report the facile synthesis of diglycolamic acid (DGA)-coated titanium dioxide (TiO2) microspherical nano-particles (TMP-DGA) for effective extraction of uranium (U(VI)) from aqueous solutions. The physical properties of the as-prepared adsorbents were carefully investigated using BET and XRD, and the presence of DGA groups was verified using FTIR, TG–DTA, and SEM–EDAX. Batch experiments were performed to assess the extraction efficiency of U(VI). The Langmuir adsorption isotherm capacity of TMP-DGA towards U(VI) was determined to be 175.87 mg g−1 at pH 6, which is substantially greater than the maximum adsorption capacity of commercial TiO2. The addition of DGA groups to TiO2 enhanced the number of active sites and enabled excellent coordination with the U(VI) species. In the presence of several contemporaneous metal ions, it has also displayed strong selectivity towards U(VI). The plausible mechanism include electrostatic attraction between U(VI) species and the DGA groups. The results of these studies show that the reported material has a remarkable ability to be utilized as an adsorbent for the removal of U(VI) from aqueous medium. [ABSTRACT FROM AUTHOR]

The objective of this study was to produce hydrophobic porous wood ceramics as adsorbents for CO2 through the resin treatment of pine. The prepared samples underwent analysis using various methods to determine their structure and properties. An orthogonal experimental approach was employed to obtain adsorbents with optimal preparation process. The highest adsorption capacity was determined to be 1.36 mmol/g at a temperature of 30 ℃ and a CO2 concentration of 15 vol%. The effect of temperature on the microstructure of wood ceramics was studied by characterization. Increasing temperatures adversely affected the adsorption capacity. Nevertheless, the hydrophobic nature of wood ceramics resulted in little impact of humidity on CO2 absorption. The CO2 adsorption kinetics of wood ceramics were analyzed using kinetic studies, which demonstrated that the kinetics can be accurately fitted by both the pseudo-first-order and Avrami models. The findings of the adsorption isotherm analysis showed that the Langmuir model fit was optimal. Following 30 cycles of adsorption-desorption in the presence of simulated gas, the CO2 sorption capacity of the wood ceramics was maintained at over 90%. In terms of CO2/N2 selectivity, the wood ceramics showed a clear preference for CO2, especially at 30 °C, where the CO2/N2 selectivity ratio reached 24.50. [ABSTRACT FROM AUTHOR]

This study explored cefuroxime sodium (CXM) adsorption on sepiolite-rich dolomite, assessing the impact of various conditions like pH, contact time, temperature, and initial CXM concentration. The research utilized data mining, kinetic and isotherm models, and analytical techniques such as FTIR, SEM, and EDX to understand the adsorption mechanism and behavior. Findings indicated that pH significantly influenced CXM adsorption, with the highest efficiency at pH 5. Additionally, the adsorption kinetics were consistent with a pseudo-first-order model, showing that adsorption was rapid and cooperative and reached equilibrium within 60 minutes, while the Freundlich isotherm model best described the adsorption isotherm. The adsorption mechanism was mainly governed by the electrostatic attraction, ion exchange, and pore-filling processes, influenced by the adsorbent's surface heterogeneity and texture characteristics, the adsorbate functional groups, and the bulk solution. Thermodynamic parameters revealed the adsorption to be spontaneous, exothermic, and entropy-driven, suggesting a predominantly physical process. While the presence of negative ΔG values showed that adsorption preferred low temperatures, the presence of a positive ΔS value showed increased randomness at the solid-liquid interface during adsorption. SEM and FTIR results confirmed the changes in the sepiolite-rich dolomite's surface properties and functional groups after CXM adsorption. EDX analysis revealed that CXM's adsorption involved the replacement of Ca2+ ions by CXM's functional groups. The study proved that sepiolite-rich dolomite can be a very effective and environmentally friendly adsorbent to remove CXM and treat bacterial infections from domestic waste or wastewater. [ABSTRACT FROM AUTHOR]

The presence of bound water in clay has a significant impact on the physical and chemical properties of clay, particularly its strength, permeability, and creep behavior. In this paper, the bound water in clay has been studied from the perspective of water potential. Initially, the adsorption isotherms of powders and consolidated samples for Na- and Ca-bentonite and illite were measured, and the bound water content was determined by subtracting the capillary water in the isotherms, with the capillary water being calculated by mercury intrusion porosimetry tests. The results indicated that bound water is independent of the void ratio and pore structure of clay, which is consistent with previous studies. Then, metadynamics was conducted to determine the adsorption free energy landscapes of the three clays, and the lowest suctions of the three clay minerals were determined to be −1.7 , −5.4 , and −2.1 GPa , respectively. Finally, through a comparison of the simulations and experiments in this study and in the literature, three important conclusions were drawn. Firstly, the lowest water potential for montmorillonite exhibits a linear relationship with the hydration free energy of exchangeable cations. Secondly, the critical water potential for tightly bound water is determined as the first inflection point in the relationship between water potential and water content, and the critical value of montmorillonite is found to be correlated to the valence of exchangeable cations. Lastly, the boundary between loosely bound water and capillary water is determined as the starting point of capillary water formation. Overall, this research highlights the importance of considering water potential as a key factor in understanding the behavior of bound water in clay. [ABSTRACT FROM AUTHOR]

Phase pure sodium trititanate (Na2Ti3O7) and hexatitanate (Na2Ti6O13) nanorods were controllably synthesized using sodium carbonate and titanic acid as sodium and titanium precursors by calcination at 850 °C for 12 h. The adsorption properties of trititanate and hexatitanate nanorods for the removal of heavy metal ions, Ni2+ and Pb2+ from simulated wastewaters at pH of 3‒7 and 20‒65 °C were investigated. The adsorption of Ni2+ and Pb2+ ions on sodium trititanate and hexatitanate nanorods are through ion exchange and electrostatic adsorption. The adsorption of Ni2+ and Pb2+ ions could be well fitted by the pseudo-second order adsorption kinetics and Langmuir adsorption isotherm. Based on the Langmuir adsorption isotherm, the adsorption capacities of naked sodium trititanate nanorods for Ni2+ and Pb2+ from simulated wastewaters at 20 °C and pH 7 are 104.17 and 89.85 mg∙g‒1 while the adsorption capacities of naked sodium hexatitanate nanorods are 95.69 and 76.69 mg∙g‒1, respectively. Sodium trititanate nanorods exhibit higher adsorption capacities for heavy metal ions from wastewaters than sodium hexatitanate nanorods because the former has richer Na+ ions for ion exchange with heavy metal ions than the latter. The adsorption processes of Ni2+ and Pb2+ on sodium trititanate and hexatitanate nanorods are spontaneous. The phase pure sodium titanate nanorods may have practical application for the removal and enrichment of metal ions from wastewaters. [ABSTRACT FROM AUTHOR]

In this study, kaolin-supported nanoscale zero-valent iron (K-nZVI) was tested as an adsorbent for the removal of phosphate from aqueous solutions. The influences of various parameters, including the kaolin to nZVI mass ratio, the solution's initial pH, the amount of K-nZVI, the initial phosphate concentration and various anions on the phosphate removal by K-nZVI were investigated. The optimum K-nZVI amount and initial pH at the initial phosphate concentration of 16 mg P/L were 0.5 g/L and pH 3, respectively, corresponding to a phosphate removal of 98.75%. The highest phosphate adsorption capacity was determined to be 82.19 mg P/g for an initial phosphate concentration of 62 mg P/L at pH 3 and 45 °C. The adsorption isotherm and kinetic followed the Freundlich and pseudo-second-order (PSO) models, respectively. A thermodynamic study demonstrated that the phosphate adsorption onto K-nZVI is spontaneous as well as endothermic. In the presence of sulfate, nitrate, and chloride anions, no phosphate removal was blocked. Instead, the removal was negatively impacted by the presence of the bicarbonate anion. The maximum phosphate desorption of 65.5% was achieved at pH 13. The results indicated that K-nZVI can be used as an efficient material for treating phosphate-rich waters. [ABSTRACT FROM AUTHOR]

Removing contaminated Arsenazo III dye from contaminated effluent is a challenge and of great interest due to its hazard and environmental impact. Therefore, the biggest challenge was producing highly efficient, easy to recycle, and economically inexpensive adsorbent materials for the contaminated dye. Three chemically stable zirconium nanocomposites with unique properties were synthesized by gel-precipitation technology. The composition, chemical, and physical properties of zirconium molybdate, tungstate, and silicate nanocomposites have been extensively proven using many different and appropriate devices such as XRD, SEM–EDX, TEM, FT-IR, BET, DLS, TGA-DTA, and zeta potential. By utilizing the most effective adsorption techniques, Azo-dye was successfully bound to ZrMo-NPs, ZrW-NPs, and ZrSi-NPs composites. The uptake capacities for these composites were measured at 0.29, 0.79, and 1.61 mmol.g−1, respectively. The sorption parameters were optimized as follows: a feed solution pH of 3 for ZrMo-NPs, a pH of 2.3 for ZrW-NPs, and a pH of 2.3 for ZrSi-NPs. The stirring time was set at 30 min, the metal ion concentration was 1.64 mmol L−1, and the sorbent dose was 7.5 mg. The adsorption results agreed well with the Langmuir isotherm and the pseudo-second-order reaction models and demonstrated the endothermic nature and kinetic improvement by increasing temperatures. The three nanocomposites effectively eliminated tainted dye from lab wastewater, offering promise for their potential applications in the future. [ABSTRACT FROM AUTHOR]

The study aimed to determine the feasibility of using compost as a 'green adsorbent' for the removal of five anionic azo dyes belonging to the monoazo, disazo and trisazo classes: Direct Red 81 (DR-81), Direct Blue 74 (DB-74), Reactive Blue 81 (RB-81), Reactive Red 198 (RR-198) and Acid Black 194 (ABk-194) from aqueous solutions. The adsorption capacity of the compost was determined using a batch method with initial dye concentrations ranging from 1 to 1000 mg/L. The kinetics of dye removal followed a pseudo-second-order model, indicating chemisorption as the rate-limiting step. The monoazo dyes RB-81, RR-198 and ABk-194 with the smaller molecule size were adsorbed the fastest. The Langmuir and Sips models best fit the adsorption system with maximum adsorption capacities in the range of 12.64 mg/g (RR-198)—20.92 mg/g (ABk-194) and 12.57 mg/g (RR-198)—25.43 mg/g (ABk-194), respectively. The adsorption depended on the dye structure, especially on the ratio of the numbers of proton donors to proton acceptor locations in functional groups. The differences in the adsorption mechanism could be explained by thermodynamic properties such as dipole moments, HOMO–LUMO energy gap, polarizability, electron affinity, ionization potential, electronegativity and chemical hardness obtained by Density Functional Theory. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine how well activated carbon made from kluwak shell (Pangium edule Reinw) works as an adsorbent to remove Pb(II) and Cu(II) heavy metal ions from wastewater used in laboratories. Kluwak shell was selected as an agricultural waste material due to its high carbon content, which makes it a promising material for activated carbon that can lower Pb(II) and Cu(II) heavy metal levels. Finding the ideal contact time, pH, and adsorption capacity as well as the kinetics and adsorption isotherm model are the main goals of this study. Using 25% KOH for carbonization and chemical activation, Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), and Surface Area Analyzer (SAA) for characterization are some of the research methods used. FTIR results showed the presence of O-H, C-H, C = C and C-O functional groups, while SEM showed more open pores after activation. SAA analysis indicated an activated carbon surface area of 3.11 m²/g, pore volume of 0.006 cm³/g, and pore diameter of 4.08 nm, categorized as mesoporous. The optimum condition for adsorption of Pb(II) ions is at pH 5 with contact time of 10 minutes and adsorption capacity of 21.83 mg/g. As for Cu(II) ions, the optimum condition is at pH 4 with a contact time of 20 minutes and adsorption capacity of 10.82 mg/g. The adsorption of metal ions is in accordance with the Langmuir isotherm model and pseudo second-order kinetics. The adsorption effectiveness of Pb(II) and Cu(II) ions from laboratory wastewater was 1.69 mg/g and 1.73 mg/g. It is concluded that activated kluwak shell can be used as Pb(II) and Cu(II) metal adsorbent. [ABSTRACT FROM AUTHOR]

The present work aimed to highlight an efficient, readily accessible, and cost-effective adsorbent derived from Dalbergia sissoo (DS) leaf powder for removing the environmentally hazardous dye "alizarin red S" (ARS) from hydrous medium. A variant of the adsorbent is activated via sulfuric acid and composited with magnetic iron oxide nanoparticles (DSMNC). Both adsorbents are thoroughly characterized using techniques such as Fourier transform infrared spectroscopy, point of zero charge, energy-dispersive X-ray spectroscopy, and scanning electron microscopy, which show that they have a porous structure rich in active sites. Different adsorption conditions are optimized with the maximum removal efficiency of 76.63% for DS and 97.89% for DSMNC. The study was highlighted via the application of various adsorption isotherms, including Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich, to adsorption data. Pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were utilized to investigate the kinetics and mechanism of adsorption. The Freundlich model and pseudo-second-order kinetics exhibited the best fit, suggesting a combination of physical interactions, as confirmed by the D–R and Temkin models. The dominant adsorbate–adsorbent interactive interactions responsible for ARS removal were hydrogen bonding, dispersion forces, and noncovalent aromatic ring adsorbent pi-interactions. Thermodynamic parameters extracted from adsorption data indicated that the removal of the mutagenic dye "ARS" was exothermic and spontaneous on both DS and DSMNC, with DSMNC exhibiting higher removal efficiency. [ABSTRACT FROM AUTHOR]

Background: The study investigated the inhibitory action of Datura discolor leaf extract against the corrosion of low-carbon steel in 0.5 M solutions of three acids. The purpose was to ascertain the effect of extract concentration, immersion time and temperature variation on corrosion inhibitory efficiency, and to relate to existing reports which show that organic molecules in most plant extracts inhibit corrosion. Extraction of the leaves was done by maceration using methanol, and solvent was removed by evaporation to dryness. Classical gravimetric (mass loss) experiments were used, and experimental data were fitted to adsorption isotherm models to ascertain the best approximation. Surface examination of the low-carbon steel substrates was carried out using the atomic force microscope. Results: Inhibitory protective efficiency of extract was found to appreciate with increasing Datura discolor leaf extract concentration at a fixed temperature, with values ranging 77.6–88.8%, 91.35–98.08% and 19.64–44.64% in H2SO4, HCl and HNO3 solutions respectively at 27 °C. Elevation of temperature was found to depreciate the inhibitor efficiency at constant inhibitor concentration. Best isotherm model fitting was obtained with Langmuir model both at 27 °C and 60 °C and in all the hostile media, while Temkin model gave good approximation only at 60 °C and in H2SO4 and HCl solutions only. The negative values of free energy of adsorption (Δ G ads 0) suggested that the adsorptive interaction of the inhibitor with the substrate surface was very spontaneous. Values of Δ G ads 0 were all consistent, fluctuating between − 16.35 and − 17.63 kJ mol−1 in both H2SO4 and HCl solutions, and between − 9.76 and − 10.25 kJ mol−1 in HNO3 solution, and this suggests that adsorption of the inhibitor molecules occurred via physisorption. Values of the activation energy of the corrosion reaction (E act) are all < 40 kJ mol−1, suggesting that the inhibition occurred by a physical adsorption mechanism. Conclusions: The study concludes that Datura discolor crude leaf extract suppressed the corrosion reactions, and the inhibition was found to arise from the physisorptive interaction of the organic molecules with the substrate/solution interface, forming a stabilize inhibitor film on the substrate surface as revealed by the atomic force micrographs. [ABSTRACT FROM AUTHOR]

A d10 Cu(I) two‐dimensional (2D) metal–organic framework (MOF) with chemical formulas, {[Cd(L)(tcm)(H2O)]⋅2H2O}n (1) (L = 1,3,5‐tris(4‐pyridylethynyl)benzene; tcm−1 = tricyanomethanide) was synthesized and structurally characterized by single crystal X‐ray diffraction method. In 1, the coordination geometry of Cu(I) ion is distorted tetrahedral coordinated to four N atoms from three L and one tcm− ligands. A 2D puckered honeycomb‐like layer is formed via the bridges of Cu(I) ions and L ligands with tris‐monodentate coordination mode. Two 2D layers are mutually interpenetrated via the π–π stacking interaction between benzene ring of L ligand and pyridyl ring of neighboring L ligand to form a two‐fold interpenetrated 2D net and then arranged orderly to construct its 3D supramolecular network. Thermal stability and in‐situ temperature‐dependent structural variations of 1 are performed by TG analysis associated with temperature‐dependent PXRD measurement. The water vapor ad‐/de‐sorption isotherm and CO2 adsorption isotherm of 1 are measured and discussed. [ABSTRACT FROM AUTHOR]

Vermiculite is extensively utilized for several applications, including as a hydroponic substrate, for soil conditioning, oil cleansing, and addressing trace metal pollution. In this study, the expansion of natural vermiculite was easily achieved by utilizing hydrogen peroxide (H2O2) with the aid of microwave technology. The characterization of expanded vermiculite involved the use of X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), nitrogen adsorption isotherm (BET), and energy dissipation X‐rays (EDX). The vermiculite has been enlarged to have a structure resembling flakes, and its surface area measures 73.9 m2/g. The adsorption of Alizarin Red S onto expanded vermiculite was investigated under varying conditions, such as pH, starting concentration, adsorbent content, and duration of exposure. The enlarged vermiculite achieved a maximum adsorption capacity of 182.5 mg/g for Alizarin Red S. Out of the three adsorption isotherm models, both the Freundlich and Temkin models accurately describe the adsorption of Alizarin Red S onto expanded vermiculite. When studying adsorption kinetics, the second‐order adsorption kinetic model is more appropriate than the first‐order adsorption kinetic model, as indicated by an R2 value of 0.8964. [ABSTRACT FROM AUTHOR]

By employing a synergistic blend of experimental and theoretical methodologies, we investigated the corrosion inhibition efficacy of a synthesized pyrazole derivative (BM-01) in a solution of hydrochloric acid (1 M). We utilized molecular dynamics (MD) simulations, scanning electron microscopy (SEM), density functional theory (DFT), complexation, plus electrochemical impedance spectroscopy (EIS). We conducted weight loss (WL) measurements from 298 to 328 K. Inhibition efficacy reached a maximum at a BM-01 concentration of 10−3 M, achieving 90.0% (EIS), 90.40% (WL), and 90.38% (potentiodynamic polarization (PDP)). SEM unveiled the shielding of the carbon-steel surface from acid-induced damage by BM-01. The Langmuir adsorption isotherm exhibited a robust fit with a low sum of squares, standard deviation, and a high correlation coefficient. PDP findings indicated that BM-01 acted as a mixed-type inhibitor, predominantly favoring the cathodic process, suggesting potential corrosion-mitigation properties. Theoretical analyses involving DFT, MD simulations, and radial distribution function were conducted to postulate a mechanism and identify an inhibitory layer. Theoretical outcomes aligned closely with experimental data, thereby reinforcing the validity of our findings. [ABSTRACT FROM AUTHOR]

AbstractThe present study used low-cost, abundant, and nontoxic kaolin and kaolin-based PVA/alginate composite (KPA) as adsorbents to remove U(VI) and Sr(II) ions from aqueous solutions. The characterization of the adsorbents was performed by several techniques. The results showed that PVA/alginate enhanced the functional groups and changed the surface morphology. Adsorption isotherm parameters were determined through both linear and non-linear regression analyses, from which it was inferred that the Langmuir model provides a better fit than other ones. The uranium removal capacity of KPA significantly improved as compared to that of kaolin, reaching 104.17 mg/g under the conditions of 30 min, pH 4.0, 298 K, and a solid-to-liquid ratio of 1.2 g/L. The strontium removal capacity of kaolin was significantly high as compared to that of KPA, reaching 68.96 mg/g under the optimum conditions. Removal of the radionuclides on both adsorbents was better described by the pseudo-second-order kinetic model, showing the ions to be immobilized on the adsorbents through chemical adsorption. Kaolin was not affected by interfering metals for U(VI) and Sr(II) adsorption, but KPA composite was influenced by the other metals. The adsorbents display potential as candidates to remove uranium and strontium from wastewater. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are superior sorbents for water adsorption‐based applications. The unique step‐like water isotherm at a MOF‐specific relative pressure allows easy loading and regeneration over a small range of temperature and pressure conditions. With good hydrothermal stability and cyclic durability, it stands out over classical sorbents used in applications for humidity control, water harvesting, and adsorption‐based heating and cooling. These are easily regenerated at moderate temperatures using "waste" heat or solar heating. The isotherm thermodynamics and adsorption mechanisms are described, and the presence of MOFs in the water–air system is explained. Based on six selection criteria ≈40 reported MOFs and one COF are identified for potential application. Trends and approaches in further synthesis optimization and production scale‐up are highlighted. No‐MOF‐fits‐all, each MOF has its own specific step location matching only with a certain application type. Most applications are technically feasible and demonstrated on the bench‐scale or small pilot. Their maturity is benchmarked by their technology readiness level. Retrofitting existing applications with MOFs replacing classical desiccants may lead to rapid demonstration. Studies on techno‐economic analysis and life cycle analysis are required for a rational evaluation of the feasibility of promising applications. [ABSTRACT FROM AUTHOR]

In this paper, cattle hair waste (CHW) was collected and physically milled into different meshes of ultrafine cattle hair powder (UCHP). The reuse of CHW reaches the purpose of treating pollution with waste by using bio-base adsorbent. It was characterized by using scanning electron microscope-energy dispersive spectrometer (SEM–EDS), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), and X-ray diffraction (XRD). The adsorption studies were carried out under different conditions of temperature, time, pH, concentration of dye solution, mesh size, and dosage of cattle hair powder, respectively. The pseudo-first and pseudo-secondary kinetics and intra-particle diffusion models were employed to analyze the adsorption kinetic. The Langmuir, Freundlich, and Temkin adsorption isotherm was used to analyze the adsorption isotherm. The results showed that the adsorption capacity of UCHP for acidic metal complex (Trupoxane Brown R6) dyes increased with the decreasing pH solution. The adsorption capacity of 200 mesh UCHP was 379.5 mg.g−1 when the adsorption conditions were as follows: 100 mL dye solution with the initial concentration of 1000 mg·L−1, the dosage of adsorbent was 0.1 g, the pH was 3 for 12 h at 40 °C. The kinetic model fitting results showed that the adsorption of dyes by UCHP conformed to the pseudo-second-order kinetic model. Adsorption thermodynamics study showed that the Langmuir model has the highest fitting result. The amino group contained on the surface of cattle hair powder and the amide bond contained in the molecular chain of peptide chain have better electrostatic adsorption binding force for acid metal complex dyes, and the binding between them is mainly electrostatic attraction. The experimental results show that the ultrafine powder has better adsorption property, which provides a high-value conversion way for recycling waste cattle hair. [ABSTRACT FROM AUTHOR]

There is a necessity for an eco‐friendly inhibitor technology to safeguard mild steel from corrosion. Redox‐active Oligoanilines, namely diamine‐capped trimer (DCTA) and tetramer (DCTAni) have been synthesized and incorporated into the polyurethane backbone derived from polyethylene glycols (PEG, Mw = 2050, 4000) and toluene diisocyanate (TDI). The four water‐soluble polyurethanes, resulting from PEG, TDI, and DCTA/DCTAni, were denoted as IH‐1, IH‐2, IH‐3, and IH‐4. The corresponding redox‐active polyurethanes were rationally characterized using FTIR, and UV–visible spectroscopies. Scanning electron microscopy (SEM) was employed to investigate the surface morphology. The electrochemical properties of these inhibitors were characterized by cyclic voltammetry (CV). All the inhibitors were studied for their corrosion inhibition efficiency using Tafel potentiodynamic polarization analysis and weight loss methods. These demonstrated high efficacy at a low concentration of 200–300 ppm. The absorptivity of polymers on the mild steel were confirmed by Langmuir adsorption isotherms with a well‐fitting (R2 = 99.9%). The SEM analysis showed the adsorption capacity of inhibitors as protective layers for the mild steel panels. Overall, this work paves the way for innovative ideas for producing more water‐soluble and electrochemically active polymer additives as excellent corrosive inhibitors for mild steel surfaces. [ABSTRACT FROM AUTHOR]

Two water‐stable indium metal‐organic frameworks, (NH2Me2)3[In3(BTB)4] ⋅ 12DMA ⋅ 4.5H2O (In‐MOF‐1) and (NH2Me2)9[In9O6(BTB)8(H2O)4(DMSO)4] ⋅ 27DMSO ⋅ 21H2O (In‐MOF‐2) (BTB=4,4′,4′′‐benzene‐1,3,5‐tribenzoate) with 3D interpenetrated structure has been constructed by regulating solvents. Structure analysis revealed that In‐MOF‐1 has a three‐dimensional (3D) structure with a single metal core, while In‐MOF‐2 features an octahedron cage constructed by three kinds of metal clusters to further form a 3D structure. The fluorescence investigations showed that In‐MOF‐1 and In‐MOF‐2 are potential MOF‐based fluorescent sensors to detect acetone and Fe3+ ions in EtOH or water with high sensitivity, excellent selectivity, recyclability and a low limit of detection. Moreover, the fluorescence mechanisms of In‐MOF‐1 and In‐MOF‐2 toward acetone and Fe3+ ions were further explained. In addition, In‐MOF‐2 has higher thermal and framework stability than In‐MOF‐1. The activated In‐MOF‐2 presents a high BET surface area of 998.82 m2g−1 and a pore size distribution of 8 to 16 Å. At the same time, In‐MOF‐2 exhibits high selective CO2 adsorption for CO2/CH4 and CO2/N2, respectively. Furthermore, the adsorption sites and adsorption isotherms were predicted using grand canonical Monte Carlo (GCMC) simulations, and the adsorption energy of the lowest‐energy adsorption configuration was calculated using molecular dynamics (MD) simulations. [ABSTRACT FROM AUTHOR]

AbstractTwo new quinoxaline derivatives namely (E)-3-(2-chlorostyryl)quinoxalin-2(1H)-one (CSQO) & (E)-3-(2-(thiophen-2-yl)vinyl)quinoxaline-2(1H)one (TVQO) were synthesized and identified through the following methods like infrared (IR) analysis, mass spectrometry,1H NMR and 13C NMR. Weight loss, electrochemical techniques [PDP&SIE], surface analytical techniques [SEM&UV-Visible], quantum chemical calculations [DFT], and MD simulations have all been used to examine the effectiveness of CSQO and TVQO in preventing the corrosion of mild steel. According to the findings of the experiments, the inhibitors CSQO and TVQO effectively suppress the corrosion of mild steel in 1 M HCl solution, with maximum corrosion inhibition of 97.0 and 95.5% at 10−3 M for CSQO and TVQO, respectively. Based on PDP investigations, CSQO and TVQO function as mixed-type inhibitors, and their adsorption on the MS surface follows the Langmuir adsorption isotherm and the mode of adsorption is chemisorption. Both surface investigations (SEM and UV-Visible) have validated the protective layer that developed on the metal surface. DFT calculations and MD simulations were used to study the association between inhibitor molecular structure [CSQO and TVQO] and inhibitory efficacy, and they closely match the experimental findings. [ABSTRACT FROM AUTHOR]

The application of low-cost biosorbent of bamboo in methylene blue (MB) removal treatment is limited by its poor adsorption performance. In this study, bamboo parenchyma cell (BP) was isolated from bamboo powder by facile method of water separation and then incorporated with natural non-toxic vermiculite (VE) to prepare bamboo parenchyma cell-vermiculite (VEBP) composites. Much more nanopores were formed and more active adsorbed sites were introduced by filling with VE in BP lumen, which is favorable for improving the MB adsorption capacity. The MB adsorption isotherm of VEBP was preferably fitted with Langmuir model, yielding the highest equilibrium MB adsorption capacity of approximately 422 mg/g. As-obtained adsorption capacity is much higher than that of BP and various kinds of biosorbents in previous researches. Besides, the adsorption kinetics was closer to the pseudo-second-order model, indicating the dominant chemisorption process. Thermodynamic parameters implied the endothermic and spontaneous as well as entropy-governed adsorption process. Based on the analysis of adsorption behavior together with characterizations of VEBP, it can be confirmed that the predominant mechanisms for MB adsorption may involve electrostatic attraction, ion exchange, hydrogen bonding, pore filling, complexation reaction, and π-π interactions. Furthermore, the VEBP exhibited excellent reusability with MB removal efficiency of more than 80% after five cycles. Therefore, this study successfully provides a facile method for preparation of bamboo-based adsorbent with efficient MB adsorption performance. [ABSTRACT FROM AUTHOR]

Abstract\nSTATEMENT OF NOVELTYRemoval of Cd(II) and Pb(II) from aqueous solutions is a challenging task and the search for novel adsorbents is underway. This study examined the efficiency of nanobiochar (NB) and rice husk (RH) in the adsorption and removal of Cd(II) and Pb(II) from water. The effect of various physicochemical parameters such as initial pH, initial Cd and Pb concentration, adsorbent dosage, and contact time were tested. SEM/EDX images confirmed the adsorption of Pb and Cd with surface physical and chemical changes. The maximum Pb removal was noted at pH 6 using NB (96%) and at pH 8 for RH (90%), and the maximum Cd removal by NB was recorded at 8 pH (91%) and by RH at pH 6 (87%). The decline in adsorption intensity at lower pH suggested protonation of the adsorbent surface causing cation-cation repulsion. Most of the adsorption occurred within the initial 60 min. A continuous gradual increase in the adsorption with time suggested multilayer formation. Of the three isotherms, the Freundlich model fits the present data best, implying an infinite surface coverage and indicating the potential for multilayer adsorption of Pb and Cd on the surfaces of RH and NB adsorbents. In conclusion, this study highlights the promising potential of NB as a cost-effective adsorbent for the removal of Cd and Pb ions from aqueous solutions.This study explores the effectiveness of utilizing low-cost natural and agricultural waste biomasses for removing Cd(II) and Pb(II) ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

To enhance the physical and chemical properties and stability of magnetic MOFs, and to improve their adsorption and reuse performance, an innovative modification strategy involving hybridization with three-dimensional (3D) terminal carboxyl hyperbranched polymers was employed. A novel polymer composite material, Fe3O4@MOF/HBPC, was synthesized and its morphological characteristics were analyzed. The adsorption properties of Fe3O4@MOF/HBPC were tested by removing Malachite Green (MG) from aqueous solutions. Various influencing factors, including dosage, pH, and temperature, as well as adsorption kinetics, isotherms, and thermodynamics were investigated. The results showed that the stretching vibration peaks of Fe3O4@MOF/HBPC appeared at 1708 cm−1, 1408 cm−1, 1278 cm−1, 1112 cm−1, and 543 cm−1, corresponding to the C＝O, –COO−, O–H, C–O, and Fe–O bands, respectively. Fe3O4@MOF/HBPC exhibited a negative charge and a spherical structure. The composite material contained the elements O, C, Fe, and N, and the assembly process had a minimal impact on the crystal structure. For MG removal, the optimal reaction conditions were a dosage of 20 mg and pH 6. The adsorption process followed a pseudo-first-order kinetic model and a Langmuir isotherm model, and it was found to be endothermic and spontaneous, involving both physical and chemical adsorption. Regarding recycling and reuse, Fe3O4@MOF/HBPC demonstrated a recycling efficiency of over 90.8%, with a removing efficiency of MG of above 87.5% after three cycles, indicating excellent stability and reusability. [ABSTRACT FROM AUTHOR]

ABSTRACT This study developed a green and efficient surface protection method for Cu–Ni alloys. A zinc dibenzyl dithiocarbamate film was prepared on the surface of electrodeposited Cu–Ni alloys using the self‐assembly method to improve the material's corrosion resistance in seawater. The influence of zinc dibenzyl dithiocarbamate concentration and self‐assembly time on the corrosion resistance of the self‐assembled films was investigated through electrochemical testing. The findings revealed that at a zinc dibenzyl dithiocarbamate concentration of 10 mmol/L and a self‐assembly time of 20 min, the self‐assembled film exhibited the most robust corrosion resistance, achieving a maximum corrosion inhibition efficiency of 97.70%. The self‐assembly and adsorption mechanism of zinc dibenzyl dithiocarbamate were explored using molecular dynamics simulations and adsorption isotherms. The protective effect of self‐assembled films was visually observed through salt spray testing. Zinc dibenzyl dithiocarbamate self‐assembled film technology has high application prospects in the field of marine anti‐corrosion. [ABSTRACT FROM AUTHOR]

Due to the increasing fluoride concentrations in water bodies, significant environmental concerns have arisen. This study focuses on aluminum-based materials with a high affinity for fluorine, specifically enhancing metal–organic frameworks (MOFs) with amino groups to improve their adsorption and defluorination performance. We systematically investigate the factors influencing and mechanisms governing the adsorption and defluorination behavior of amino-functionalized aluminum-based MOF materials in aqueous environments. An SEM, XRD, and FT-IR characterization confirms the successful preparation of NH2-MIL-101 (Al). In a 10 mg/L fluoride ion solution at pH 7.0, fluoride ion removal efficiency increases with the dosage of NH2-MIL-101 (Al), although the marginal improvement decreases beyond 0.015 g/L. Under identical conditions, the fluoride adsorption capacity of NH2-MIL-101 (Al) is seven times greater than that of NH2-MIL-101 (Fe). NH2-MIL-101 (Al) demonstrates effective fluoride ion adsorption across a broad pH range, with superior fluoride uptake in acidic conditions. At a fluoride ion concentration of 7 mg/L, with 0.015 g of NH2-MIL-101 (Al) at pH 3.0, adsorption equilibrium is achieved within 60 min, with a capacity of 31.2 mg/g. An analysis using adsorption isotherm models reveals that the fluoride ion adsorption on NH2-MIL-101 (Al) follows a monolayer adsorption model, while kinetic studies indicate that the predominant adsorption mechanism is chemical adsorption. This research provides a scientific basis for the advanced treatment of fluoride-containing wastewater, offering significant theoretical and practical contributions. [ABSTRACT FROM AUTHOR]

To remove phosphate from water, a novel Fe-doped ZIF-8 was synthesized as a superior adsorbent. The Fe-doped ZIF-8 was fully characterized using different characterization techniques and it was found that the as-prepared Fe-doped ZIF-8 (denoted as ZIF-(2Zn:1Fe)) showed a polyhedral morphology with a large specific surface area of 157.64 m2/g and an average pore size of 3.055 nm. Analyses using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction showed that Fe atoms were successfully incorporated into the ZIF-8 skeleton. Batch experiments demonstrated that the molar ratio of Fe and Zn has effects on phosphate adsorption. The adsorption kinetics conformed to a pseudo-second-order model with a high correlation coefficient (R2 = 0.9983). The adsorption isotherm matched the Langmuir model (R2 = 0.9994) better than the Freundlich model (R2 = 0.7501), suggesting that the adsorption of phosphoric acid by ZIF-(2Zn:1Fe) can be classified as a chemisorption on a homogeneous surface. The adsorption amount was 38.60 mg/g. It was found that acidic environments favored the adsorption reaction and the best adsorption was achieved at an initial pH of 2. Inhibition of adsorption by common anions is NO3-> CO32-> SO42-> Cl-. Characterization results indicate that the main mechanism of adsorption is surface complexation interactions. [ABSTRACT FROM AUTHOR]

This study systematically investigates the optimization of synthesis parameters for ternary layered double hydroxide (LDH) to achieve a pure phase and high crystallinity. The [Co0.52+Al0.253+Fe0.253+(OH)2].(CO32−)0.125.mH2O$[{\mathrm{Co}}_{0.5}^{2 + }{\mathrm{Al}}_{0.25}^{3 + }{\mathrm{Fe}}_{0.25}^{3 + }({\mathrm{OH}})_2 ].({\mathrm{CO}}_3^{2 - })_{0.125}.{\mathrm{m}}{\mathrm{H}}_2{\mathrm{O}}$, LDH is synthesized using the coprecipitation method and applied for wastewater treatment. The ternary LDH is synthesized at 60 °C for 24 h and exhibited maximum crystallinity with a crystallite size of 4 nm. The crystallinity index (CI) is a quantitative indicator of crystallinity, which is calculated using the X‐ray diffraction (XRD) method. The influence of reaction time on the structural characteristics of this LDH was thoroughly investigated, mainly focusing on achieving well‐crystalline LDH. Experimental results revealed a direct correlation between reaction time and crystallinity. This study highlights the significant influence of controlled synthesis and reaction time on producing high crystalline ternary LDH. The role of different parameters, such as solution pH, adsorbent dosage, contact time, and dye concentration, has been investigated. The adsorption isotherm data is analyzed using different isotherm models, which shows this material having a significant adsorption capacity of 82.92 mg/g for Congo Red dye. [ABSTRACT FROM AUTHOR]

The current work was designed to eliminate reactive yellow 18 dye (RY‐18) via adsorption from water, and CO2 from the gas stream, using the tragacanth gum‐based Cr doped NiO N.P.s/Clay (GCNC) composite. The one‐pot synthesis approach was used to produce the adsorbent, and physical and chemical properties were assessed using techniques like XRD, FTIR, UV‐visible spectroscopy, SEM, DLS, Zeta Potential, and adsorption–desorption isotherm. The GCNC composite demonstrated an impressive adsorption potential and percentage removal of 398 mg/g and 91.28%, respectively. Temkin and intraparticle diffusion models with R2 values of 0.98401 and 0.99918 were the most effective at fitting the experimental adsorption model. The thermodynamics parameters, including the change in enthalpy (H), entropy (S), and Gibbs free energy (G), demonstrated the endothermic and spontaneous nature of the adsorption process. A positive H value indicates an endothermic process, while a negative G value indicates a spontaneous process. According to the isotherms fitting model, the capacity for adsorbing CO2 at 25 °C and 1 atm was 4.8 mmol/g. The significant correlation between the slope in the log‐linear plot of the isosteric heat of adsorption and CO2 adsorption performance indicates that the isosteric heat of adsorption can be used as a predictive tool for CO2 adsorption performance. These significant results underscore the potential of the GCNC composite to revolutionize the water treatment field and CO2 capture, offering hope for a more sustainable and cleaner future. [ABSTRACT FROM AUTHOR]

Green processes for synthesizing nanocomposites are a hot area of research today as traditional processes are expensive, inefficient, harmful for synthesizing organic and inorganic molecules, and unsuitable for large-scale operations. The present study investigates the capacity of green synthesized Calcium oxide nanoparticles (CaO NPs) for efficiently removing Rhodamine B. Chemical reduction was replaced with Mulberry (Morus nigera) leaf extract as an environmentally friendly reaction mechanism. CaO NPs are characterized by various analytical techniques including EDX, BET, SEM, FTIR, TGA, Zeta Potential, Point of Zero Charge (PZC), and XRD. Maximum adsorption of Rhodamine B by CaO NPs is revealed at an initial concentration of Rhodamine B of 80 ppm, a temperature of 343 K, and contact time of 60 min, 0.4 g of adsorbent at a pH value of 7. Maximum removal of Rhodamine B by CaO NPs was found to be 98.2% which is promising with this small amount of adsorbent (0.4 g). Diverse Kinetic and adsorption isotherms are employed in this study to determine the requirement and significance of the adsorption process. Various adsorption isotherms such as Freundlich, Temkin, Dubinin–Radushkevich (D–R), and Langmuir models have been employed. Among the kinetic adsorption isotherms Elovich, Intraparticle kinetic model, pseudo 1st order, and pseudo 2nd order models were applied. The current study investigates the thorough understanding of the Rhodamine B adsorption process including the mechanism of adsorption using condition optimization, characterization, and model applications. The proposed adsorbent can be employed for the green removal of Rhodamine B from wastewater of industry with maximum efficiency and favorable regeneration properties. [ABSTRACT FROM AUTHOR]

Ternary bio-adsorbent was synthesized by using sisal fiber as a base with the integration of conductive polymer; polyaniline (PANI), supported with zero-valent iron nanoparticles by chemical activation with potassium hydroxide. The activation temperature impact on adsorption properties of Sisal fiber composite activated carbon was studied. The activation temperatures had a major effect on adsorption process as 100% removal efficiency was attained at 800 °C activated temperature. Scanning electron microscopy (SEM) was used for surface analysis of the adsorbent. Adsorption isotherms (Langmuir, Freundlich and Temkin) were examined and the negative values of 1 / n F demonstrated that the adsorption data does not match with Freundlich model for chemisorption. The pseudo second order and Elovich kinetics correlation coefficients for the retention of Fe and Cd to solid-phase interface at SF-800/NP/PANI (C) offered a better correlation for the bio-adsorption of Fe and Cd than pseudo first order kinetic. However, the pseudo second order kinetic attained a surpassing interaction for the bio-adsorption of Fe (0.989) than Cd (0.966); while the Elovich kinetic attained a surpassing interaction for the bio-adsorption of Cd (0.975) than Fe (0.945). The recovery and recycling stability of the bio-adsorbent composites were studied. [ABSTRACT FROM AUTHOR]

AbstractIn this study, copper-bismuth oxide/iron oxide (CuBi2O4@Fe3O4) nanocomposites were prepared by microwave-assisted synthesis and used as adsorbents for the adsorptive removal of cadmium from textile wastewater. The pH/volume of buffer solution, mixing type/period and adsorbent dosage were optimized univariately to enhance the removal efficiency of the adsorbent and determined as 1.5 mL of pH 8.0 buffer solution, vortexing for 60s, and 30 mg of CuBi2O4@Fe3O4 nanocomposite material. Following the determination of the optimum parameters, equilibrium adsorption studies were performed at five different initial concentrations of cadmium within the range of 0.50 − 10 mg L−1 in textile wastewater. A matrix-matching calibration strategy was utilized for the accurate and precise quantification of cadmium in the wastewater matrix with a R2 value of 0.9961. The percent removal efficiencies were calculated within the range of 77.2 − 81.5% for the adsorptive removal of cadmium ions from textile wastewater in the equilibrium adsorption experiments. Furthermore, the Langmuir, Freundlich, and Sips adsorption isotherm models were employed for modeling the equilibrium data, and the results showed that all the models fitted well with the experimental data with R2 values higher than 0.99. The simple and efficient batch adsorption process developed was successfully utilized to remove cadmium ions from textile wastewater. [ABSTRACT FROM AUTHOR]

The corrosion inhibition action of Phalaris canariensis extract on 316 L stainless steel in the H2O-35 (wt%) LiCl mixture at different temperatures has been evaluated with the aid of weight loss, potentiodynamic polarization curves, linear polarization resistance and electrochemical impedance spectroscopy tests. These studies were complemented by Fourier Transformed Infrared spectroscopy, FTIR, gas/mass chromatography analytical techniques and detailed scanning electronic microscopy studies. Results have indicated that Phalaris canariensis extract is an efficient inhibitor, with an efficiency that increases with its concentration, but it decreases as the temperature increases. Phalaris canariensis extract is physically adsorbed onto stainless steel according to a Temkin type of adsorption isotherm. Phalaris canariensis extract affected both anodic and cathodic electrochemical reactions with a stronger effect on the anodic ones, acting, thus, as a mixed type of inhibitor. Main compounds contained in the Phalaris canariensis extract were palmitic and oleic acids, responsible for its inhibitory properties. [ABSTRACT FROM AUTHOR]

Phosphonic acid (PA) self‐assembled monolayers (SAMs) were deposited onto Pt/Al2O3 catalysts to modify the support to enable control over CO2 adsorption and CO2 hydrogenation activity. Significant differences in catalytic activity toward CO2 hydrogenation (reverse water‐gas shift, RWGS) were observed after coating Al2O3 with PAs, suggesting that the reaction was mediated by CO2 adsorption on the support. Amine‐functionalized PAs were found to outperform their alkyl counterparts in terms of activity, however there was little effect of amine location in the SAM (i. e., spacing between the amine functional group and phosphonate attachment group). One amine‐PA and one alkyl‐PA, aminopropyl phosphonic acid (C3NH2PA) and methyl phosphonic acid (C1PA), respectively, were investigated in more detail. The C3NH2PA‐modified catalyst was found to bind CO2 as a combination of carbamate and bicarbonate. Additionally, at 30 °C, both PAs were found to reduce CO2 adsorption uptake by approximately 50 % compared to unmodified 5 %Pt/Al2O3. CO2 adsorption enthalpy was measured for the catalysts and found to be strongly correlated with hydrogenation activity, with the trend in binding enthalpy and CO2 hydrogen rate trending as uncoated >C3NH2PA>C1PA. PA SAMs were found to have weaker effects on CO binding and CO selectivity, consistent with selective modification of the Al2O3 support by the PAs. [ABSTRACT FROM AUTHOR]

Rapid industrialization has led to significant environmental challenges, including the disposal of effluents with high zinc ion concentrations. This study investigates the use of hydroxyapatite nanoparticles as an adsorbent for Zn (II) ions from aqueous solutions at neutral pH. These nanoparticles are characterized by their high purity, mesoporous structure, and a specific surface area of 60.97 ± .40 m2 g−1. Their thermal stability was confirmed by thermogravimetric analysis, and zeta potential measurements indicated a surface charge close to the isoelectric point. Adsorption experiments showed that the kinetics fit well with the pseudo‐second‐order model, with a rate constant of 2.58 ± .49 min−1 mg−1 and a determination coefficient (R2) of 1.00. Isotherm analyses using Redlich–Peterson, Langmuir, and Freundlich models revealed the highest adsorption capacity and best fitting with the Redlich–Peterson model, showing maximum capacities of 30.36 mg g−1 (linear fitting) and 32.11 mg g−1 (nonlinear fitting). These fits achieved R2 values of .9949 and .9923, respectively, suggesting efficient and reliable adsorption profiles. This research highlights the potential of hydroxyapatite nanoparticles for effective zinc ion removal, supporting their application in sustainable industrial practices and environmental remediation. [ABSTRACT FROM AUTHOR]

Phosphonic acid (PA) self‐assembled monolayers (SAMs) were deposited onto Pt/Al2O3 catalysts to modify the support to enable control over CO2 adsorption and CO2 hydrogenation activity. Significant differences in catalytic activity toward CO2 hydrogenation (reverse water‐gas shift, RWGS) were observed after coating Al2O3 with PAs, suggesting that the reaction was mediated by CO2 adsorption on the support. Amine‐functionalized PAs were found to outperform their alkyl counterparts in terms of activity, however there was little effect of amine location in the SAM (i. e., spacing between the amine functional group and phosphonate attachment group). One amine‐PA and one alkyl‐PA, aminopropyl phosphonic acid (C3NH2PA) and methyl phosphonic acid (C1PA), respectively, were investigated in more detail. The C3NH2PA‐modified catalyst was found to bind CO2 as a combination of carbamate and bicarbonate. Additionally, at 30 °C, both PAs were found to reduce CO2 adsorption uptake by approximately 50 % compared to unmodified 5 %Pt/Al2O3. CO2 adsorption enthalpy was measured for the catalysts and found to be strongly correlated with hydrogenation activity, with the trend in binding enthalpy and CO2 hydrogen rate trending as uncoated >C3NH2PA>C1PA. PA SAMs were found to have weaker effects on CO binding and CO selectivity, consistent with selective modification of the Al2O3 support by the PAs. [ABSTRACT FROM AUTHOR]

This study presents the use of novel Ganga-sand-encapsulated polyaniline granules for effective remediation of textile and pharmaceutical wastewater. The prepared Ganga-sand-encapsulated polyaniline granules were characterised using scanning electron microscope (morphology) and Fourier transform infrared techniques. The effect of adsorbent dose, contact time, pH and concentration influence on the adsorption performance of Ganga-sand-encapsulated polyaniline granules for the removal of methylene blue dye (textile waste) and doxycycline antibiotic (pharmaceutical waste) was studied. Kinetic and isotherm studies were also carried out to investigate the adsorption process further. The maximum adsorptive removal efficacy of methylene blue and doxycycline was found as 98.2% and 85.1%, respectively, at the optimised condition of adsorbent dose: 8 g/L, time: 120 min, pH: 12 and concentration: 50 ppm. From adsorption kinetics, it was established that the adsorption process followed pseudo-second-order (PSO) rather than pseudo-first-order (PFO). The correlation coefficient values for PFO and PSO models were 0.9012 and 0.9992, respectively, for methylene blue dye adsorption on Ganga-sand-encapsulated polyaniline granules. The adsorption isotherm study established that the adsorption process followed the Langmuir model rather than the Freundlich model. This study found that Ganga-sand-encapsulated polyaniline granules can be a promising adsorbent for textile and pharmaceutical wastewater treatment. [ABSTRACT FROM AUTHOR]

This study investigated the adsorption properties of graphene oxide in a magnetic-assisted adsorber for the depollution of water containing heavy metals. Two samples of graphene oxide with different surface chemistry were synthetized and assessed using the magnetic-assisted adsorption systems. One graphene oxide sample exhibited a dual magnetic behavior presenting both diamagnetic and ferromagnetic phases, while the other graphene oxide was diamagnetic. The adsorption properties of these graphene oxide samples for removing Pb2+ and Cu2+ were tested and compared with and without a magnetic field exposure. The results showed that the Pb2+ removal increased using both graphene oxide samples in the magnetic-assisted configuration, while Cu2+ adsorption was less sensitive to the application of the magnetic field. A monolayer model was used to simulate all the heavy metal adsorption isotherms quantified experimentally. It was concluded that the adsorption mechanism designed to remove Pb2+ and Cu2+ using tested graphene oxide samples was mainly multi-ionic where two metallic cations could interact with one active site (i.e., oxygenated functional groups) from the adsorbent surface. The oxygenated surface functionalities of graphene oxide samples played a relevant role in determining the impact of magnetic field exposure on the heavy metal removal efficacy. Magnetic-assisted adsorption using graphene oxide is an interesting alternative to reduce the concentration of Pb2+ in polluted effluents, and it can also be applied to improve the performance of adsorbents with a limited concentration of oxygenated functional groups, which usually show poor removal of challenging water pollutants such as toxic heavy metals. [ABSTRACT FROM AUTHOR]

Owing to the toxicity and widespread use of copper, the pollution caused by copper ions has become a long-standing environmental and industrial challenge. In this study, a new adsorbent was developed to dispose of and remove copper ions from water. The modified chitosan–carboxymethyl starch (MCTS-CMS) polymer was characterised, and FTIR and SEM-EDS confirmed the successful graft modification of the receptor. The adsorption behaviour was investigated through various parameters, and the results showed that the optimal parameters were pH > 4.0, an adsorption time of 30 min, a reaction temperature of 293 K, and an initial concentration of 100–120 mg/L. The experimental data exhibited a good fit with pseudo-second-order models, and the Langmuir isotherm revealed that the polymer was found to be highly suitable for adsorption, with a maximum adsorption capacity of 321.16 mg/g. Thermodynamic analysis revealed that the adsorption process was exothermic and spontaneous. XRD and XPS confirmed the generation of posnjakite after the adsorption and the predominant roles of nitrogen- and sulphur-containing groups in the adsorption. Further analysis confirmed the existence of chemisorption and physical adsorption, with chemisorption mainly facilitating the Cu(II) absorption of the polymer. MCTS-CMS showed an excellent removal efficiency of 98% in acidic solutions. On the basis of these findings, the MCTS-CMS polymer demonstrates excellent performance and high selectivity in the removal of copper ions from industrial wastewater or polluted water bodies. This work recommends expanding the polymer's practical applications to contribute to water purification efforts. [ABSTRACT FROM AUTHOR]

Context: In this comparative study of the adsorption of l-phenylalanine (l-Phe) on two modified low-activated carbons (ACK and ACZ) at four temperatures (293–313 K), steric and energetic characteristics of adsorption were investigated. An advanced statistical physics multilayer model involving single-layer and double-layer adsorption scenarios was developed to interpret the l-Phe adsorption phenomenon. Modeling results indicate that two and three l-Phe layers were arranged depending on the tested adsorption systems. The estimated number of l-Phe molecules per leading adsorption site varied from 1.71 to 2.09 and from 1.76 to 1.86 for systems l-Phe-ACK and l-Phe-ACZ, respectively. The results show that a multimolecular adsorption mechanism might connect this amino acid molecule on ACZ and ACK surfaces in a non-parallel location. These parameters changed as follows, according to the adsorbed quantity at saturation analysis: Qasat (l-Phe-ACK) ˃ Qasat (l-Phe-ACZ). This indicates that ACK material was more efficient and valuable for l-Phe adsorption than ACZ. It was also shown that the adsorption capacity decreases as the temperature increases, proving the exothermicity of the adsorption process. This analytical substantiation is confirmed by calculating the binding energies, suggesting the occurrence of physical bonds between l-Phe amino acid molecules and ACK/ACZ binding sites and among l-Phe–l-Phe molecules. Pore size distribution was interpreted and calculated by applying the Kelvin theory to data from single adsorption isotherms. All used temperatures depicted a distribution of pores below 2 nm. The docking analysis involving l-Phe and the ACZ and ACK adsorbents reveal a significant resemblance in how receptors detect ligands. Consequently, the findings from the docking process confirm that the calculated binding affinities fall within the spectrum of adsorption energy. Methods: This study analyzed the adsorption capacity of the l-Phe through a model proposed by statistical physics formalism. Molecular docking was used to determine the various types of interactions between the two activated carbons. Two aspects, including orientation of l-Phe on the site, number of molecules per site n, interaction energy, density of receptor site, and adsorption capacity, were discussed to elucidate the influence of activation on the two adsorbents. [ABSTRACT FROM AUTHOR]

This study investigates the removal efficiency of Cu2+ from wastewater using a composite hydrogel made of carbon nanotubes (CNTs), sodium alginate (SA), and polyacrylic acid (PAA) prepared by free radical polymerization. The CNTs@SA/PAA hydrogel's structure and properties were characterized using SEM, TEM, FTIR, XRD, rheology, DSC, EDS, elemental mapping analysis, and swelling. The adsorption performance for Cu2+ was tested in batch adsorption experiments, considering the pH, dosage, initial concentration, and contact time. The optimal conditions for Cu2+ removal were pH 5.0, an adsorbent dosage of 500 mg/L, and a contact time of 360 min. The adsorption followed pseudo-second order kinetics. Isotherm analyses (Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Sips, Toth, and Khan) revealed that the Freundlich isotherm best described the adsorption, with a maximum capacity of 358.52 mg/g. A thermodynamic analysis indicated that physical adsorption was the main interaction, with the spontaneity of the process also demonstrated. This study highlights the high efficiency and environmental friendliness of CNT@SA/PAA composites for Cu2+ removal from wastewater, offering a promising approach for water treatment. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSIn this study, the ability of live mycelia of Schizophyllum commune to remove heavy metals from aqueous solution was investigated. The influence of various experimental parameters, such as pH, temperature, and contact time on the biosorption process was investigated. The maximum biosorption capacity using live biomass was found as 81.5, 90.71, 70.18, and 66.18 mg/g for Pb(II), Sr(II), Zn(II), and Cd(II), respectively, at optimized conditions. The biosorption process reaches equilibrium between 180 and 240 min for the tested metal ions. The experimental data were used to study biosorption isotherm and kinetics models. The thermodynamic parameters, ΔG°, ΔH°, and ΔS°, showed that the biosorption process was endothermic and spontaneous at 303–343 K. SEM images revealed that the presence of metal ions altered the morphology of fungal hyphae. The presence of Pb(II), Sr(II), Zn(II), and Cd(II)on the fungal mycelia was confirmed using SEM-EDX. FTIR spectroscopy of biomass showed the involvement of functional groups like, -CH, amino acid, fatty acid, carboxyl group, and alkane and alkyl groups in adsorption of heavy metal ions. The adsorption capacity of S. commune for removal of heavy metals under the optimized conditions was Sr(II) > Pb(II) > Zn(II) > Cd(II). Thus, the study demonstrated an application of Schizophyllum commune for efficient removal of heavy metals from metal-contaminated water or industrial effluents.The maximum biosorption capacity were 81.5, 90.71, 70.18, and 66.18 mg/g for Pb(II), Sr(II), Zn(II), and Cd(II), respectively.Optimum conditions for the maximum adsorption were pH 4–5, temperature 60–70 °C, and contact time of 180–240 min.The biosorption process was endothermic and spontaneous at 303–343 K and fitted Langmuir isotherm model and pseudo-second-order kinetics.The functional groups including -CH, amino acid, fatty acid, carboxyl group, and alkane and alkyl groups were responsible for the adsorption of metal ions.The maximum biosorption capacity were 81.5, 90.71, 70.18, and 66.18 mg/g for Pb(II), Sr(II), Zn(II), and Cd(II), respectively.Optimum conditions for the maximum adsorption were pH 4–5, temperature 60–70 °C, and contact time of 180–240 min.The biosorption process was endothermic and spontaneous at 303–343 K and fitted Langmuir isotherm model and pseudo-second-order kinetics.The functional groups including -CH, amino acid, fatty acid, carboxyl group, and alkane and alkyl groups were responsible for the adsorption of metal ions. [ABSTRACT FROM AUTHOR]

Phosphorus in wastewater from pressed vegetables is a significant contributor to water pollution, emphasizing the importance of its removal and recycling for ecological management. In this study, an improved method of coprecipitation pyrolysis of Mg(OH)2 and FeCl3•6H2O was used to successfully synthesize iron-magnesium biochar composite (FeMg@BC2) from corn cob. Compared with iron-modified biochar (Fe@BC), magnesium-modified biochar (Mg@BC), and iron–magnesium-modified biochar (FeMg@BC1) prepared by traditional coprecipitation methods, the improved iron–magnesium biochar had higher yield, specific surface area, and crystallinity. The study investigated the impact of modified biochar dosage, initial solution pH, and coexisting ions on the adsorption capabilities of modified biochar for phosphate removal. The results demonstrated that the addition of 1.0 g/L FeMg@BC2 was highly effective in removing phosphate from simulated wastewater when the phosphate concentration was 80 mg/L, achieving a removal rate exceeding 95%. Using an adsorption isotherm model, the maximum phosphate adsorption capacities of Fe@BC, Mg@BC, FeMg@BC1, and FeMg@BC2 were estimated to be 40.76, 46.97, 96.78, and 107.97 mg/g, respectively. Particularly, FeMg@BC2 exhibited superior phosphate adsorption capacity, and its adsorption mechanism mainly included electrostatic attraction, surface precipitation, and ligand exchange. The desorption test of phosphorus-loaded modified biochar revealed that the desorption rates of FeMg@BC2 from simulated wastewater and pressed vegetable wastewater using a 0.5M NaOH solution were 92.2% and 84.8%, respectively. After three cycles of adsorption in pressed vegetable wastewater, the phosphorus removal efficiency of FeMg@BC2 at 1.0 g/L remained about 50%. Therefore, the utilization of FeMg@BC2 for phosphorus recovery from pressed vegetable wastewater showed promising potential. [ABSTRACT FROM AUTHOR]

A simple strategy is presented for the preparation of Prussian blue-modified g-C3N4. PB/g-C3N4 is synthesized as an efficient adsorbent for the adsorption of U (VI), and the effects of various conditions on the adsorption of U (VI) are investigated. Static adsorption experiments reveal that the adsorption of U (VI) by PB/g-C3N4 conforms to the Langmuir adsorption isotherm and pseudo-second-order adsorption model. The composition and morphology of the materials are characterized by XRD, FT-IR, XPS, SEM, and BET. This study demonstrates that PB/g-C3N4 is a promising material for uranium-containing wastewater treatment, with the advantages of low cost, environmental friendliness, and facile synthesis. [ABSTRACT FROM AUTHOR]

In this study, an adsorption method using a synergistic effect between ultrasound and negative pressure cavitation was developed for the efficient recovery of paclitaxel from the culture supernatants of Taxus chinensis onto an adsorbent Diaion HP-20. The equilibrium adsorption data were matched to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms, and the Langmuir model was found to be the best fit. As the ultrasonic power and negative pressure intensity increased, the adsorption capacity and adsorption rate constant increased, and the intraparticle diffusion resistance sharply decreased. The combined ultrasound and negative pressure cavitation method achieved the best adsorption, and the synergistic effect was up to 65% at ultrasonic powers/negative pressure intensities of 80 W/–50 mmHg to 250 W/–200 mmHg. Paclitaxel adsorption onto Diaion HP-20 was endothermic and spontaneous. In addition, the isosteric heat of adsorption does not depend on surface loading, so the adsorbent has an energetically homogeneous surface. [ABSTRACT FROM AUTHOR]

Rational utilization of fly ash, a widely emitted solid waste, was explored by investigating the effects of various factors on the types and properties of zeolites prepared from fly ash. Additionally, the mechanism for adsorption of ammonium nitrogen onto NaP zeolite synthesized via a one-step hydrothermal method was explored. The characterization studies included scanning electron microscopy (SEM), X-ray diffraction (XRD), and adsorption of ammonium nitrogen from wastewater. The effects of the crystallization time, solid‒liquid ratio, alkali concentration, and crystallization temperature on the performance of the fly ash-derived zeolites were systematically investigated. Adsorption isotherms and kinetic models were employed to analyze the adsorption behavior and mechanisms. The results indicated that the optimal conditions for the zeolite synthesis included a 24-hour crystallization time, a solid‒liquid ratio of 1:10, an alkali concentration of 3 mol/L, and a crystallization temperature of 150°C. Under these conditions, the zeolite exhibited intense diffraction peaks, a large surface area, a regular morphology, and an ammonia-nitrogen adsorption rate of 73.01%. An orthogonal test revealed that the alkali concentration had the most significant impact on the zeolite synthesis, with a range value of 14.28. The isothermal adsorption data for ammonia-nitrogen were consistent with the Freundlich model, while the kinetic studies showed that pseudosecond-order kinetics governed the process. [ABSTRACT FROM AUTHOR]