Adsorption Of Ions Research Articles

The Effects of Foaming Agent and Surfactant on Alkali Activated Materials as an Adsorbent for Lead Ions Adsorption

Lead, a hazardous environmental metal, has been widely used in various applications, either pure or alloyed with other metals. This study investigates the impact of foaming agents and surfactants content on the physical properties of metakaolin-based alkali activated materials. Additionally, it seeks to assess the effectiveness of metakaolin-based AAM adsorbent in removing lead ions. The research uses varying percentages of foaming agents (1 wt.%, 1.25 wt.%, and 1.5 wt.%) and surfactants (1 wt.%, 3 wt.%, and 5 wt.%). Water absorption, density and porosity tests were used to evaluate the metakaolin-based alkali activated adsorbent’s physical properties. Scanning Electron Microscopy (SEM) was used to study the morphology of the adsorbent. In addition, the adsorption test was investigated to determine the lead ion removal in the AAM adsorbent. The ion removal performance of metakaolin based alkali activated materials was evaluated based on different amounts of foaming agent and surfactant. A lead (II) solution was prepared in distilled water and used in the adsorption test. An adsorption test was carried out to determine the effectiveness of AAM with a foaming agent and surfactant, which showed that it could be suited to many harsh conditions. This study successfully identified the optimal parameters for achieving maximum efficiency in lead ion removal, featuring a concentration of 1.25 wt.% of foaming agent and 3 wt.% of surfactants. These findings hold significant promise for the advancement of effective adsorbents, particularly in the realm of wastewater treatment processes.

Hydrogen Peroxide Modification Enhances the Ability of Metakaolin based Alkali Activated Materials Adsorbent to Remove the Ni2+ Ions

The presence of nickel ions in wastewater is a significant environmental concern due to its toxicity, which can cause severe health problems. Metakaolin is a pozzolanic material that can be activated by alkali to produce a highly porous and reactive material that can be utilised as a heavy metal ion adsorbent. However, the adsorption capacity of metakaolin-based adsorbents is limited by their surface chemistry and porosity. Metakaolin-based alkali-activated materials adsorbent modified with hydrogen peroxide can effectively remove nickel ions from wastewater. The modification process increases the surface area and porosity of the adsorbent, enhancing its adsorption capacity. The modified adsorbent (1.00 wt.% H2O2) showed a higher sorption capacity of 26.57 mg/g and efficiency of 85.22% compared to the non-modified adsorbent (10.55 mg/g) sorption capacity and 45.63% nickel removal efficiency, indicating the potential of hydrogen peroxide-modified adsorbents as an economical and ecologically sustainable solution for environmental applications, particularly for metal immobilization.

Ultrastable Seawater Oxidation at Ampere-level Current Densities with Corrosion-resistant CoCO3/CoFe Layered Double Hydroxide Electrocatalyst.

Hydrogen is an essential energy resource, playing a pivotal role in advancing a sustainable future. Electrolysis of seawater shows great potential for large-scale hydrogen production but encounters challenges such as electrode corrosion caused by chlorine evolution. Herein, a durable CoCO3/CoFe layered double hydroxide (LDH) electrocatalyst is presented for alkaline seawater oxidation, showcasing resistance to corrosion and stable operation exceeding 1,000 h at a high current density of 1 A cm-2. The results indicate that CoCO3 within the electrocatalyst undergoes conversion into CoOOH and releases CO3 2- during electrolysis. The incorporation of CO3 2- within its layers and the anchoring of the electrocatalyst's surface prevent the adverse adsorption of chloride ions, enhancing resistance to chloride ion corrosion, thereby protecting the active sites of the electrocatalyst effectively.

Reversibly Switchable Magnetically Controlled Solid‐Liquid Triboelectric Nanogenerator Using Hierarchical Ecoflex/NdFeB Magnetic Polymer Surface

AbstractDroplet‐driven triboelectric nanogenerator (TENG) with reversible switching capability has been widespread concerned; particularly magnetically controlled solid‐liquid TENG, due to its fast and highly reversible responses. Herein, a hierarchical composite structured magnetic polymer surface (HCSMPS) is developed using template method and magnetic field induction, and construct a HCSMPS‐based TENG (HCSMPS‐TENG). The HCSMPS‐TENG shows different states—fallen, upright, and no magnetic field—when applying different magnetic fields. The wetting properties of HCSMPS under three states vary significantly. The current output of the HCSMPS‐TENG driven by deionized water and potassium chloride (KCl) solution varies across these states due to changes in the droplet contact area. As KCl concentration increases, the current signals of the HCSMPS‐TENG initially rise due to the increased free charges but subsequently decrease due to a screening effect caused by ion adsorption. For practical application, a real‐time monitoring system is developed for KCl concentration based on the HCSMPS‐TENG, integrating a convolutional neural network. This system, equipped with a compact current collection circuit capable of remote data transmission and a user‐friendly interface developed with LabVIEW, achieves 98.64% recognition accuracy. The HCSMPS‐TENG is applied to intravenous potassium supplementation, demonstrating its potential for medical KCl concentration and infusion flow rate monitoring.

Rare Earth Elements Induce Drought Tolerance in Dicranopteris pedata from Ion-Adsorbed Rare Earth Mining Area in Southern China

The ion adsorption rare earth (IARE) mining areas in southern China frequently experience severe seasonal drought, posing significant challenges to plant growth. This study investigates the hypothesis that rare earth elements (REEs) present in these mining areas induce drought resistance in Dicranopteris pedata (D. pedata). An experiment was designed with three drought stress intensities (0%, 5%, and 10% PEG6000) and three levels of rare earth element (REE) addition (none, low, and high). After 72 h of drought stress, physiological indices and metabolomic profiles of D. pedata were examined. The results showed that under drought conditions, the REE additions increased the catalase and peroxidase activities of D. pedata by 99.04% and 81.25%, respectively, and the contents of proline, soluble proteins, and soluble sugars by 97.52%, 71.24%, and 61.81%, respectively. Metabolomic analysis revealed up-regulation of lipid and lipid-like molecules, as well as flavonoid metabolism, which contribute to improved drought resistance in D. pedata under stress. Furthermore, REE addition further up-regulated flavonoid and anthocyanin synthesis compared to drought stress alone, enhancing the plant’s resilience to drought. These findings suggest that D. pedata responds to drought stress by modulating enzyme activities, osmoregulatory substances, and metabolic pathways upon REE exposure. This study underscores the dual role of REEs in enhancing both the drought tolerance and enrichment capacity of D. pedata in IARE mining areas, which is crucial for sustaining plant growth amidst drought stress, and provides new ideas for the ecological restoration and sustainable development of IARE mining areas.

Kinetic and Thermodynamic Study of Ag+, Cu2+, and Zn2+ Ion Adsorption on LTA for High-Performance Antibacterial Coating

Antibacterial powder coatings have attracted increasing attention with the awakening of people’s health awareness. Silver antibacterial agent has been widely used in coating system due to its superior stability and durability. However, silver ions have the problems of excessive release rate and the tendency to cause yellowing of the coating film. The addition of Cu2+ and Zn2+ can effectively alleviate these two phenomena. In this paper, the ternary exchange kinetics of Ag+, Cu2+, and Zn2+ were studied to provide a theoretical basis for the synthesis of LTA-Ag-Cu-Zn. The reaction kinetics study shows that the selectivity and the adsorption capacity of LTA to Ag+ is higher than that of Cu2+ and Zn2+. The thermodynamic analysis discovers that LTA has the highest selectivity for Ag+, and the exchange between the two is spontaneous. In contrast, the selectivity of LTA to Cu2+ and Zn2+ is concentration-dependent. By establishing the three-ion competitive adsorption curve, it is found that the selectivity of Ag+ is the highest, and the selectivity of copper and zinc is similar. These trends result from Ag+ ions’ low hydration energy, small hydration radius, and strong electronegativity. This research lays the groundwork for developing high-performance LTA-Ag-Cu-Zn tri-ion exchange antibacterial agents.

Solvent-free synthesis of covalent-framework 2D crown ether and its application for polylactic acid nanocomposites having antibacterial property

This study showed the synthesis of a covalent-frameworked 2D crown ether, named C2O, consisting of carbon and oxygen in a 2:1 mol ratio, using solvent-free synthesis for the first time. The synthesized C2O is distinguished by its structure, which includes numerous phenol groups akin to phlorotannins, conferring high antibacterial property through contact-based mechanisms and biocompatibility. The inherent crown ether structure of C2O facilitates efficient metal adsorption, allowing for the easy facile preparation of C2O containing Cu atom (Cu@C2O). Cu@C2O exhibits enhanced antibacterial property at much lower concentrations compared to the native C2O. For practical application, polylactic acid (PLA) nanocomposite films were prepared using C2O as a filler, achieving 99.99 % of antibacterial property at just 0.1 wt% concentration. When the PLA nanocomposite films were prepared using Cu@C2O as the filler, the required concentration was further reduced to 0.03 wt%, while still demonstrating 99.99 % of antibacterial property. Additionally, the excellent copper ion adsorption capacity of Cu@C2O ensures minimal leaching, thus mitigating cytotoxicity concerns. Given their high and long-term antibacterial properties, biocompatibility, these materials represent promising candidates for various biomedical, packaging and antifouling paint applications, demonstrating significant potential across diverse domains.

Sustainable synthesis and environmental application of chitosan-Ocimum basilicum leaves-ZnO composite membrane for permanganate ion removal in wastewater treatment.

This study introduces a novel and environmentally friendly method for developing a cross-linked chitosan-Ocimum basilicum leaves-ZnO (ChOBLZnO) composite membrane, specifically designed for the adsorption of permanganate ions (MnO4-) from wastewater. Various characterization techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) surface area analysis, were employed to confirm the membrane's synthesis quality, structural integrity, and surface properties crucial for adsorption. The BET analysis revealed a surface area of 228.64 m2/g, indicating a highly porous structure. The membrane exhibited a high adsorption capacity of 142.8mg/g and an outstanding removal efficiency of 98.5%. The adsorption kinetics were best described by the pseudo-second-order model, with a correlation coefficient (R2) of 0.998, while the Freundlich isotherm model provided the most accurate fit for the adsorption behavior, with an R2 of 0.995. Thermodynamic studies indicated that the adsorption process is spontaneous and endothermic, with negative Gibbs free energy and positive enthalpy and entropy values. Reusability tests showed that the ChOBLZnO composite membrane maintained a high removal efficiency across five cycles, with minimal performance loss. These results demonstrate the ChOBLZnO composite membrane's potential as an efficient and sustainable solution for wastewater treatment, offering both high efficiency and durability.

Improving copper ions adsorption using Ca-modified NaY zeolite synthesized from calcined rice husk ash

Improving copper ions adsorption using Ca-modified NaY zeolite synthesized from calcined rice husk ash

Mentioned Magnesium Oxide Nanomaterials for Effective Adsorption of Congo Red Dye and Fluoride Ions From Aqueous Solutions

This study investigates the synthesis of nanostructured magnesium oxide (MgO) using the auto-combustion method with urea (MgO-U), glycine (MgO-G), and citric acid (MgO-C) as fuels, followed by subsequent calcination. The selection of fuel plays a crucial role in determining the morphology of the nanostructures.X-ray diffraction (XRD) analysis confirms that the samples exhibit a well-crystallized structure with the desired phase and are free of impurities. Field emission scanning electron microscopy (FESEM) shows that MgO-U nanoparticles have diameters ranging from 10 to 20nm, MgO-C nanoparticles from 60 to 80nm, and MgO-G nanoparticles from 80 to 100nm. These MgO nanomaterials are specifically engineered for adsorption applications, aimed at removing toxic organic dyes and fluoride ions from aqueous solutions. Results demonstrate that MgO-G nanoparticles exhibit superior adsorption activity compared to MgO-U and MgO-C nanoparticles, with maximum uptake capacities of 1429 and 14mg/g, respectively. The adsorption processes adhere to second-order kinetic model. These findings highlight the potential application of the synthesized MgO nanoparticles for mitigating water pollution by adsorbing pollutants from aqueous media.

Adsorption of ferrous ions onto phosphoric acid-activated biochar

Adsorption of ferrous ions onto phosphoric acid-activated biochar

In situ evolved high-valence Co active sites enable highly efficient and stable chlorine evolution reaction

The chlor-alkali process is crucial in the modern chemical industry, yet it is highly energy-intensive, consuming about 4 % of global electricity due to the significant overpotential and low selectivity of existing chlorine evolution reaction (CER) electrocatalysts. Although advanced electrocatalysts have reduced the energy demands of the chlor-alkali process, they typically incorporate precious metals. Here, we introduce a novel precious metal-free electrocatalyst, (CoZn)3V2O8@C, with a hollow nanocube structure that exhibits outstanding CER performance. It features an overpotential of just 69 mV, a selectivity exceeding 90 %, and a high durability of 250 h at a current density of 10 mA/cm2, surpassing commercial dimensionally stable anodes (DSA) and some precious metal-based electrocatalysts. Comparative experiments and physical characterizations reveal that during the CER, high-valence Co evolves in situ due to the formation of adjacent Zn vacancies from the partial dissolution of Zn in (CoZn)3V2O8@C. Density functional theory further confirms that Zn vacancies can modify the electronic structure of the adjacent Co, enhancing the adsorption and activation of chloride ions, reducing the energy barrier of the reaction, and thereby improving the catalytic performance of CER.

Charge injection dynamics in oxygen-functionalized and heteroatom-doped reduced graphene oxide and their impact on supercapacitor performance: An experimental and DFT investigation

To elucidate the synergistic effects of oxygen functional groups (OFGs) and heteroatoms (HAs) on charge injection dynamics and the electrochemical performance of reduced graphene oxide (rGO), a combination of experimental techniques and density functional theory (DFT) analyses were employed. GO was synthesized using a modified Hummers method and the sample reduced hydrothermally at 150 °C demonstrated the highest areal capacitance of 817 mF/cm2. To understand the diffusion and charge transfer characteristics, the diffusion coefficient and distribution of relaxation time studied using the Electrochemical Impedance Spectroscopy data. Further the X-ray photoelectron spectroscopy (XPS) confirmed the incorporation of OFGs and HAs in the rGO. A partially oxygen-functionalized, nitrogen, and sulfur-doped graphene (NS-POG) model was constructed based on the XPS data and analyzed using DFT. The projected density of states analysis revealed a Fermi level shift, indicating the introduction of excess electrons due to incorporating OFGs and HAs in graphene, thereby improving the charge carrier concentration in the partially reduced or oxidized systems. The NS-POG system exhibited a quantum capacitance of 85.92 μF/cm2. Additionally, potassium ion (K+) adsorption studies indicated that the adsorption energy was highest near sulfur atoms, suggesting that electrolyte ions exhibit enhanced electrochemical activity in proximity to sulfur. These findings provide insight into the mechanisms by which OFGs and HAs enhance the performance of rGO and highlighting the potential of NS-rGO in supercapacitor applications.

Hybrid organic - inorganic filter system for cadmium ions adsorption from aqueous solutions

The study reflects on the problem of heavy metals, namely cadmium, polluting the natural environment. The goal was to select the most efficient adsorber enabling ion exchange between calcium and cadmium in an aqueous environment and subsequently design a material hybrid organic-inorganic, particle-fiber system that adsorbs cadmium from aqueous environments and will be easily included in the technological process. The novelty of this study lies in the use of waste food material – eggshells as a source of biogenic nanoparticles. These are applied to a nanofibrous structure made of polyvinyl butyral in amounts of 8 to 10 %wt by weight by the AC electrospinning. (The experiment was performed with these boundary conditions: temperature was 23°C, and humidity was 42%. The high-electrical voltage amplifier generated a sinusoidal waveform with a frequency of 50 Hz and an amplitude of 32 kV) and were used for ion exchange. In ion exchange, cadmium ions are exchanged with calcium ions based on the principle of chemical similarity of the two elements expressed by the z/r ratio (charge/ radius ratio), the z/r ratio is 2.02 for calcium ions Ca2+ and 2.06 for cadmium Cd2. Separateted nanoparticles of calcium carbonate obtained by burning eggshells (727°C) with dimensions from 100 to 200 nm and a specific surface area of 3.9 m2/g showed the highest adsorption capacity of 99.8%, synthetic calcium carbonate at 71.8%, and ground eggshells the lowest at 25.0%. Designed and laboratory-tested filter system of nanoparticles - nanofibers captures 95.6% and 96.8% of cadmium ions from an aqueous solution within 10 minutes and 90 minutes, respectively, at a concentration of cadmium ions of 10 mg/l, and at several nanoparticles of 0.3 g. The ion exchange is carried out only on the filter surface, and after a specific time, the calcium carbonate nanoparticles are released from the filter probably due to absence of chemical bond between nanoparticles and nanostructures or the low density of the nanofibrous structure. SEM, EDX, FTIR, BET and TGA analysis were used for material evaluation. The adsorption capacity of used nanoparticles and filter adsorbers was evaluated according to residual amounts of cadmium ions in aqueous solutions using ICP-IOS.

Studies of the kinetics and isotherms of copper ions adsorption on APTES-modified silica materials

Studies of the kinetics and isotherms of copper ions adsorption on APTES-modified silica materials

Physicochemical analysis and sequential extraction of rare earth elements from Malaysian ion-adsorption clays

Abstract The growing demand for Rare Earth Elements (REEs) has spurred the search for new sources, including ion adsorption clays. This research focused on characterizing ion-adsorption clay minerals and sequentially extracting samples from Kelantan, Malaysia, to assess their potential for REE extraction. Techniques such as XRF, XRD, and ICP-MS were used to analyze the samples, which primarily consisted of Si, Al and Na. XRD results indicated that kaolinite and quartz were the main components of ion adsorption clay. Sequential extraction revealed that most REEs were in the ion exchangeable fraction, with lanthanum, cerium, and neodymium showing higher concentrations. This study advances REE extraction methods and lays the groundwork for future research

Jackfruit waste derived oxygen-self-doped porous carbon for aqueous Zn-ion supercapacitors

To fully harness the benefits of high energy density, strategic fabrication of hierarchical porous carbon (PC) materials is essential and highly impactful. In this study, oxygen-self-doped PC materials are synthesized from jackfruit waste (JK) through pyrolysis combined with chemical activation. The resulting material (JKPC-4) features abundant interfacial active sites and a short ions/electrons transfer distance, enhancing the ion adsorption capacity and kinetic behavior of the cathode. Additionally, the oxygen-rich functional groups contribute to increased pseudocapacitance and enhance the wettability and conductivity of the material. Consequently, the assembled JKPC-4//JKPC-4 symmetric supercapacitor in 2M Na2SO4 electrolyte exhibits a high energy density of 36.06 Wh kg−1 at 647.94 W kg−1. Furthermore, the JKPC-4//Zn device demonstrates a notable capacity of 225 mAh g−1 at 0.1 A g−1, exceptional rate capability (93 mAh g−1 at 10 A g−1), high energy density (154 Wh kg−1), and impressive cycle stability, retaining 97 % of its capacity after 10,000 cycles at 10 A g−1. The electrochemical process is studied using ex-situ characterization. Mechanistic studies have shown that the outstanding energy storage capability and charge-transfer processes of JKPC-4 stem from the synergistic interplay between oxygen heteroatoms and suitable pore structure.

Non-carbonization annealing toward regulation of cobalt-based organic–inorganic hybrids as advanced electrocatalysts for water splitting

High-temperature carbonization typically used in the preparation of advanced electrocatalysts poses significant challenges in preserving abundant functional groups essential for reactant adsorption and component stabilization. To address this, a solvothermal synthesis followed by non-carbonization annealing approach is proposed to fabricate a series of cobalt-based organic–inorganic hybrids derived from cobalt-based glycerate nanospheres (GNs). Notably, annealing in phosphorous and inert atmospheres preserves the solid nanospherical structure, whereas treatment in sulfur-rich environments results in the formation of hollowed nanospheres. Among these hybrids, phosphorized solid cobalt GNs (Co-P-GNs) exhibit the highest catalytic activity for hydrogen evolution reaction (HER), achieving a low overpotential of 152 mV at 10 mA cm−2. Meanwhile, sulfurized hollow cobalt-iron GNs (Co-Fe-S-HGNs) demonstrate good performance in catalyzing oxygen evolution reaction (OER), with a low overpotential of 273 mV at 10 mA cm−2. Both catalysts exhibit robust stability and maintain 100 % Faradaic efficiency during operation in electrolyzers for water splitting. The high performance not only stems from the well-dispersed phosphide and sulfide crystallites, offering ample catalytic active sites; but also benefits from the partially thermolyzed organic matrix enriched with heteroatoms and functional groups, which facilitates ion adsorption to initiate the reactions and tightly clenches loaded components to stabilize the active species.

Atomic insights of structural, electronic properties of B, N, P, S, Si-doped fullerenes and lithium ion migration with DFT-D method.

Battery interface research can effectively guide battery design and material selection to improve battery performance. However, current electrode material interface studies still have significant limitations. In this paper, by employing DFT-D method, the influences of doping elements (boron, nitrogen, phosphorus, sulfur, and silicon) on the properties of C60 fullerene, such as structural stability, electronic properties, and the adsorption and migration of lithium ion, are comprehensively investigated. It is demonstrated that doping can bolster the fullerene molecule's structural integrity and enhance charge transfer comparing with C60, thereby augmenting the material's electrical conductivity. Among the five doping elements, B-doping exhibits the most favorable adsorption energies, indicating a strong lithium binding affinity. This observation is supported with energy barrier of lithium ion migration. B-doping leads to an elevated barrier (0.37eV) comparing with pristine C60 (0.19eV), whereas Si-doping significantly reduced barrier (0.038eV) indicates enhanced lithium-ion mobility. These findings solid the efficacy of doping as a strategy to enhance the performance of fullerene electrodes. All DFT calculations were performed using the VASP software package. The chosen computational technique was a combination of the generalized approximate gradient function PBE with the dispersion correction (DFT-D3) developed by Grimme. The results of the calculations were analyzed with the help of VASPKIT.

Extracted microbial exopolysaccharides: a sustainable approach to bioremediation of nickel, cobalt and copper ions; equilibrium, kinetics and thermodynamics studies

ABSTRACT The adsorption of nickel, cobalt and copper ions onto the surface of exopolysaccharides extracted from cyanobacterial mats has been studied to provide a sustainable and efficient approach for the remediation of heavy metals. The physical characterisation of the EPS surface, including SEM, EDX and FTIR, confirmed an irregular compact structure with multiple cracks, rough macropore structure and the existence of hydroxyl, amine, amide, polysulphide and carbonyl groups. The maximum adsorption capacity (q max 47.17 , 47.02 and 46.95 mg/g for Cu(II), Co(II) and Ni(II), respectively) was achieved at pH = 6, 0.3 g/L EPS dose, 120 min duration time and 35°C. The remediation affinity of EPS decreased in the order of Ni(II) > Co(II) > Cu(II). The Langmuir model (R 2 > 0.95) better fits the adsorption behaviour than the Freundlich model (R 2 < 0.90) and the Dubinin – Radushkevich isotherm model, indicating chemical adsorption between the biosorbent and metal ions. Kinetically, the pseudo-second-order model better describes adsorption than does the pseudo-first-order model. Finally, thermodynamic studies have demonstrated that the adsorption process is spontaneously endothermic, with positive enthalpy values (ΔH°) and negative free energy (ΔG°). The positive entropy values (ΔS°) indicate an increase in disorder at the solid-liquid interface during the adsorption process.