Search

Silica aerogels have attracted widespread attention for their distinct nanoporous networks, composed of interconnected silica nanoparticles and high-volume nanosized pores. Nonetheless, producing silica aerogels with low costs and simple processes still remains a considerable challenge. Herein, the mesoporous silica aerogels were prepared from inorganic silicon source through the freeze-drying. Using sodium silicate as the silica precursor, the gel was formed by the ion exchange and sol-gel in sequence. The regeneration of the weak acidic ion exchange resin produced the sodium acetate solution, which can be potentially used as carbon source for sewage treatment. To eliminate the collapse of microstructure of the silica hydrogel during freeze-drying, the tert-butanol aqueous solution was used as the freeze-drying medium. Particularly, the direct mixing of tert-butanol and silica sol to generate wet gel avoids prolonged and material-consuming solvent replacement. The pore structure of mesoporous silica aerogel can be adjusted by changing the concentration of tert-butanol solution. The 18 wt % tert-butanol solution results in the most favorable mesoporous structure of silica aerogel, owing to the eutectic behavior within the gel, which was verified by differential scanning calorimetry (DSC) analysis, and also due to the superior and uniform mesoporous structure of wet gel, which was validated by the cryogenic scanning electron microscopy (cryo-SEM) observation. Under optimal process conditions, the obtained silica aerogel exhibited a high porosity (97.74%) and typical mesoporous structure with the large pore volume (4.84 cm3 g−1) and an average pore diameter of 24.40 nm. The proposed cost-effective preparation strategy could elevate the potentials for large scale applications of silica aerogels in the fields of thermal insulation for building, industrial catalysis and adsorption, etc. [ABSTRACT FROM AUTHOR]

This study introduces an innovative approach to enhance operational efficiency and reduce the energy consumption of seawater desalination through electrodialysis (ED) by expanding the beneficial outputs beyond desalinated water. In addition to hydrogen (H 2) gas production, the system is designed to generate nutrient-rich water for hydroponic farming by selectively recovering essential ions from seawater. The core innovation lies in integrating Monovalent Selective Membranes-Electrodialysis (MVS-ED) with ion-exchange resins (IEX-R). The new configuration allows for the selective removal of monovalent ions while preventing the leakage of multivalent ions such as magnesium and calcium, which are captured by the IEX-Rs. The ED cell simultaneously generates hydrogen gas at the cathode, with the separation of anolyte and catholyte solutions facilitating efficient gas collection. Several experiments are conducted using seawater under varying current densities and voltages, achieving a 96.23% removal of harmful ions (NaCl) from the seawater. The results reflect that the maximum H 2 gas generation rate achieved is 18 mmol/h while applying 15 mA/cm2 of current density and 8 V of applied potential. The system's minimum net energy consumption was calculated as 6.43 kWh/m3 of desalinated seawater with the benefit of producing carbon-free H 2 gas. The specific energy consumption for ion removal was 0.521 kWh/g, with energy and exergy efficiencies of 20.73% and 29.57%, respectively. This integrated MVS-ED and IEX-R system represents a significant advancement in sustainable desalination technology, offering a dual benefit of clean energy production and nutrient recovery, paving the way for resource-efficient agricultural practices and a sustainable future. • MVS-ED reduces energy consumption to 6.43 kWh/m³ while producing H₂. • IEX-R + MVS-ED emerges asa potential way to tackle water scarcity and energy issues. • Maximum energy efficiency of MVS-ED is achieved as 20.73%. • Maximum exergy efficiency of MVS-ED is achieved as 29.57%. • Maximum hydrogen production rate is achieved as 18 mmol/h. [ABSTRACT FROM AUTHOR]

We present a study on the hydrothermal synthesis of BaTiO 3 utilizing NaTi 3 O 6 (OH)- (H 2 O) 2 nanowires, which was conducted by controlling temperature, alkalinity and time. Initially, increased temperature has promoted the synthesis of BaTiO 3 and induce a change in the morphology. When the temperature increases within the range of 90 °C–210 °C, the morphology of the product transitions from nanoparticle to spindle-shaped to nanowires. Then, a time-dependent experiment was conducted to investigate the mechanisms involved in the transformation of the morphology. The formation of nanoparticle occurs through the process of dissolution-crystallization, while the formation of BaTiO 3 nanowires is attributed to hydrothermal ion exchange. Also, the hydrothermal process is characterized by grain aggregation and grain growth. By investigating the synthesis and morphology evolution of BaTiO 3 , this work holds significant potential for the synthesis of BaTiO 3 nanowires or other perovskite-type MTiO 3 employing titanate as a precursor. [ABSTRACT FROM AUTHOR]

The single-doped Cu+ glass obtained by ion exchange preparation process was studied. The exchange depth of copper ions in the glass reached 50 μm–150 μm (prepared at 370 °C–530 °C, 16 h). XPS and Raman testing showed that the glass network polymerization degree of the thin glass (thickness 0.2 mm) was lower than that of the thick glass (thickness 2 mm), and the optical alkalinity of the thin glass surface was lower than that of the thick glass. The proportion of monovalent Cu ions coordinated in octahedra in the thin glass sheet was higher than that in the thick glass sheet. PL studies had shown that under the condition of ion exchange at 370 °C for 16 h, the fluorescence intensity and fluorescence quantum efficiency of thin glass samples were higher than those of thick glass samples. The fluorescence quantum efficiency of thin glass samples reaches 56.88%, and they also have good thermal stability. [ABSTRACT FROM AUTHOR]

Recently, the pivotal to electrocatalytic water splitting is developing efficient and earth-abundant electrocatalysts to accelerate the sluggish kinetics of hydrogen and oxygen evolution reactions (HER and OER). In this work, (NH 4) 2 MoS 4 derived from polyoxometalates ((NH 4) 6 Mo 7 O 24 ·4H 2 O) were immobilized onto the ion exchange resin D314, and highly dispersed Co-molybdenum disulfide (Co–MoS 2 @NG-4) on nitrogen-doped graphene catalyst was prepared. The optimized Co–MoS 2 @NG-4 shows excellent electrocatalytic performance for HER and OER. Specifically, the low overpotentials of 202 and 352 mV are required to drive the current density of 10 mA cm−2 with the small Tafel slope of 77.30 and 153.50 mV dec−1 for HER and OER, respectively. The Co–MoS 2 @NG-4 demonstrates excellent stability, maintaining a robust operation for 5000 cyclic tests with no detectable stability decay. Porous structure endows Co–MoS 2 @NG-4 with more active centers, increasing its specific surface area and ultimately improving its catalytic performance. [Display omitted] • Synthesized Co–MoS 2 @NG-4 catalyst using ion-exchange and thermal reduction methods. • The porous structure and heteroatom doping improve the electrocatalytic activity. • The Co–MoS 2 @NG-4 exhibits excellent electrochemical activity for both HER and OER. • The Co–MoS 2 @NG-4 exhibits exceptional stability. [ABSTRACT FROM AUTHOR]

This work aimed to optimize, produce and characterize Cu-doped bioactive glasses which are antibacterial without the addition of antibiotics obtained via ion exchange in an aqueous solution. According to morphological, compositional and structural analyses, 0.001 M was selected as the most optimal concentration of the ion exchange solution. The doped glass was then compared to the undoped one to investigate the effect of Cu-doping on the glass surface composition and bioactivity. Cu-doping was found to enhance the bioactivity kinetics and the following hydroxyapatite formation, evidenced by X-ray diffraction, energy dispersive X-ray spectroscopy, and zeta potential measurements. Besides that, the zeta potential titration measurements confirmed that the Cu-doping did not alter the surface chemical stability of the glass both in the inflammatory and physiological pH range. Moreover, the leaching ability of Cu2+-ions, both in physiological and inflammatory-mimicking conditions, was measured, followed by an in-depth study of the antibacterial properties, using two protocols to distinguish between the antiadhesive, antibacterial, and antibiofilm effects. For both protocols, a reduction of metabolic activity and Colony-Forming Unit after 24 h against Staphylococcus aureus Multi-Drug resistance strain was evidenced. These results showed that Cu-doped glass could show potential as a bioactive and antibacterial surface for bone surgery applications. [ABSTRACT FROM AUTHOR]

Through this work, we show the potency of Quintinite (Mg–Al-Layered Double Hydroxide with Mg/Al ratio ∼2) as an efficient toxic dye (Amido Black 10B) adsorbent. Our strategy involves a facile, scalable synthesis of Layered Double Hydroxide (LDH) with magnesium as divalent and aluminium as trivalent ions in Mg/Al ratio ∼2 that forms a layered structure of metal hydroxides balanced by anions which develops a net positive charge on the surface in an aqueous medium. Adsorption behaviour examined via UV–Visible Spectrometry showed rapid dye adsorption for low dye concentrations (∼99% in 2 min) and displayed a high adsorption capacity of 207 mg/g at higher dye concentrations. These adsorption results were one of the highest reported ever to date with quintinite or any pristine Mg–Al-LDH processed below 100 °C. The mesoporous adsorbent surface together with a net positive charge in an aqueous medium provided an additional advantage in possessing more active adsorbing sites on the adsorbent (Mg–Al-LDH). We attempt to unravel the fact that, the LDH with appropriate preparation conditions can deliver maximum efficiency without any additional modification. [Display omitted] [ABSTRACT FROM AUTHOR]

The emerging problem of nickel allergy is increasingly widespread due to the increase in nickel content in everyday foods. The physicochemical structure of the zeolites makes it possible to adsorb nickel ions in solution. The properties of molecular sieves, together with those of a size and a chemical composition compatible with the human gastrointestinal tract, are present in a particular zeolite called clinoptilolite. In this work, a type of natural clinoptilolite was characterized before and after being subjected to two different conditioning processes with NaCl to increase its adsorption efficiency and specificity against nickel. The three forms of clinoptilolite, natural, conditioned, and biconditioned, were compared based on analysis of absolute density, X-ray diffraction pattern, granulometry, porosity, chemical composition, and grain morphology. Finally, nickel ion removal tests were performed in an aqueous solution that simulates the conditions of the gastrointestinal tract. The Ni2+ removal efficiency of natural clinoptilolite is 73.2%, while after conditioning it reaches 96.6%. Double conditioning with Na does not generate a considerable increase in removal efficiency which remains at 96.8%. [ABSTRACT FROM AUTHOR]

The ultra-high lime aluminum method (UHLA) is a method that can effectively adsorb chloride ions in a solution. Calcium oxide (CaO) and sodium aluminate (NaAlO2) were mixed and added to the sodium chloride solution. After the reaction lasted for some time, the content of chloride ions in the solution was significantly reduced. Through the experiment of chloride ion adsorption, it was found that when the mass ratio of calcium oxide to sodium aluminate was m(NaAlO2):m(CaO) = 1:2.5, the reaction temperature was 25°C, and the stirring time was 60 min, the adsorption effect on chloride ion was the best. The adsorption rate can reach 93.3% in a 100 mg/L sodium chloride solution. With the increased sodium chloride concentration, the time required to reach adsorption equilibrium becomes longer. In a 2,000 mg/L sodium chloride solution, this method's unit adsorption mass of chloride ion can reach 63.5 mg/g. Through SEM and XRD analysis, calcium oxide and sodium aluminate react in solution to form Ca4Al2(OH)14 with a layered structure. The OH- between the layers can exchange with external chloride ions. After Ca4Al2(OH)14 adsorbs chloride ions, the product is Friedel's salt (Ca4Al2Cl2(OH)12) with the same layered structure. [ABSTRACT FROM AUTHOR]

Ion exchange of a glass-ceramic system with a specific crystalline phase can lead to materials with superior chemical, physical and mechanical properties. The aim of this study is to characterize newly synthesised nepheline glass-ceramics for dental restorative applications. Four novel experimental glasses based on the nepheline composition were ground into fine powders and then sinter-crystallized into monolithic glass-ceramics. The developed glass-ceramics were characterized before and after ion exchange in a potassium nitrate bath using X-ray diffraction, EDX-SEM, and biaxial flexural strength, hardness and solubility testing in accordance with ISO-6872. The ion exchange process of nepheline containing glass-ceramic Al20 increased the characteristic strength by more than 163 % compared to the starting value. The experimental glass-ceramics increased in strength after ion exchange compared to their as-sintered values by 139 %, 24 % and 123 %. The strength scatter decreased after ion exchange for the nepheline-containing glass-ceramics by 10 %. The characterised glass-ceramics in this work require further investigation and have the potential to be developed into layered glass powders, which can be ion exchanged after sinter-crystallization to produce dental restorations with superior mechanical and chemical properties. [ABSTRACT FROM AUTHOR]

An ion exchange process in a power plant was investigated to provide a means to lower operating costs by optimizing exchange ratios of used resins. Ion exchange resins were obtained and tested according to ASTM standards to find the difference of capacity after long term use. Moreover, we used Fourier-transform infrared spectroscopy (FT-IR) methods to identify the adsorbed impurities and exhausted functional groups. The cation and anion exchange resins showed a drop of 0.39 and 0.53 eq/L in total capacity, respectively, also corresponding to the drop and increase of peaks found through FT-IR. Finally, a cost analysis was conducted to optimize the performance of ion exchange resins with the lowest cost possible. Our results showed that ion exchange processes are heavily related to operation costs. A proposed total cost of ownership model will help stakeholders decide on cost-effective ion exchange processes while being able to maintain ultrapure quality. Moreover, results conducted through standardized tests will be able to compare with the results provided. [ABSTRACT FROM AUTHOR]

• Lithium leaching efficiencies peaked at calcination temperature of 600 °C and leaching temperature of 80 °C; • A lithium leaching efficiency of 96.18% was obtained by mixed solution of H 2 SO 4 and FeCl 3 ; • As the calcination temperature rises, mineral structures became collapsed, amorphous, activated, and subsequently turned into stable; • Lithium leaching is considered to be caused by ion exchange; • The entry of Fe3+ into the mineral interlayer not only released Li+ but also increased the interlayer spacing and facilitated the ion exchange. The demand for lithium resources continues to grow owing to the extensive application of lithium-ion batteries in the clean energy industry, and in consequence the development of lithium extraction technologies is significant. In this study, the mixed solution of H 2 SO 4 and FeCl 3 was found to have a synergistic effect on the lithium extraction from a clay lithium ore. Upon calcination at 600 °C for 60 min, followed by leaching with a mixture of 10.5 w% H 2 SO 4 and 2 w% FeCl 3 at a liquid-to-solid ratio of 5 mL/g for 90 min at 80 °C, a lithium leaching efficiency of 96.18 % was obtained, better than using individual H 2 SO 4 and FeCl 3 at higher concentrations. The TG-DTG-DSC, FTIR, BET and XRD results showed that with the increase of calcination temperature the structures of partial minerals such as kaolinite and cookeite became collapsed, amorphous, unstable and activated, which favored for the release of lithium. With the further increase of calcination temperature, the mineral structure continued to collapse and tends to be stable, making the interlayer lithium tightly fixed and difficult to be released. The XRD and SEM results indicated that the lithium extraction is an ion exchange process rather than mineral dissolution. The synergistic effect of H 2 SO 4 and FeCl 3 on the lithium extraction was attributed to the fact that the entry of Fe3+ into the interlayer of the layered structure of clay minerals not only released Li+, but also increased the interlayer spacing, conducive to the access of H+ to the interlayer, and consequently facilitated the ion exchange of H+ and Li+. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cationic covalent organic framework with triazine and pyridine (COF-Tys) is designed by directly introducing quaternary ammonium. • COF-Tys demonstrates excellent chemical stability and radiation resistance. • COF-Tys exhibits high efficiency and remarkable selectivity in capturing 99TcO 4 -/ReO 4 - from diverse contaminated water. • The predominant adsorption mechanism for 99TcO 4 -/ReO 4 - is proved to be anion exchange. Efficient elimination of 99TcO 4 - is crucial for radioactive waste management and environmental protection, but achieving outstanding stability and high selectivity remains a major challenge for the reported adsorbents. In this study, we report a cationic covalent organic framework based on pyridine and triazine (COF-Tys) for the selective extraction of 99TcO 4 -/ReO 4 - (a non-radioactive surrogate of 99TcO 4 -). COF-Tys exhibits excellent stability under acidic or irradiation conditions. Experimental results reveal that COF-Tys possesses high adsorption capacity (422.61 mg/g for ReO 4 -), rapid kinetics (removing over 99% of 99TcO 4 - within 5 min), and promising recyclability (less than a 1.5% decrease in ReO 4 - removal after five adsorption/desorption cycles). Notably, COF-Tys demonstrates remarkable selectivity, adsorbing more than 90% of 99TcO 4 - even in simulated radioactive solutions with excess competing ions. Furthermore, COF-Tys achieves 97.5% and 80.4% removal of 99TcO 4 - from contaminated groundwater and seawater within 10 min, respectively. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses confirm that the primary mechanism of 99TcO 4 -/ReO 4 - adsorption involves anion exchange between Cl- and 99TcO 4 -/ReO 4 -. In conclusion, COF-Tys holds tremendous potential as a high-performance adsorbent for the separation of 99TcO 4 - from radioactive wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Supply risk associated with critical elements including Sb, Bi, In, Ga, Ge, and Te is discussed. • The characteristics of tailings generated during sulfide ore processing are summarized. • Recent advancements and limitations in extraction technologies for the selected critical elements are thoroughly reviewed. • Influencing factors affecting the extraction processes are analyzed. • Potential areas of future research for critical minerals recovery from mining and metallurgical wastes are introduced. Modern industries that are involved in the design and development of high-technology products rely heavily on the availability of critical materials. As a result, there has been a growing global interest in the exploration and development of diversified production processes to meet the future demand for these essential elements. Due to the continuous depletion of primary sources and the associated supply risks, the reprocessing of secondary repositories has emerged as a promising solution. This approach offers both economic and environmental advantages by providing a sustainable supply of critical elements and addressing environmental concerns. One significant source of critical elements is the tailings generated from the physical beneficiation (mineral processing) and downstream processing (extractive metallurgy) of polymetallic sulfide minerals which is the focus of this article. This review article provides a systematic understanding of the potential recovery of selected critical elements, namely Sb, Bi, In, Ga, Ge, and Te from the sulfide ore supply chain and assess the feasibility of recovering them from tailings. It also discusses the main separation processes for these elements with specific emphasis on froth flotation and hydrometallurgy practices that involve physical separation, leaching, precipitation, solvent extraction, and ion exchange techniques. Furthermore, the review addresses the various challenges and opportunities, as well as emerging trends that are likely to influence future research directions in this field. The insights gained from this analysis are invaluable for researchers aiming to develop effective methods for extracting these critical elements from non-traditional and unconventional resources. [ABSTRACT FROM AUTHOR]

• The pore structure of MIL-53 was tuned by solvent change, creating abundant free 1D channels. • The Mn cluster was feasibly incorporated into the MIL-53 by exchanging BDC2- ligands under mild conditions. • The content of hydroxy group and open metal sites (OMS) were tuned by monocarboxylic modification and ion exchange. • The Al/Mn bimetallic MIL-53 showed superior uptake on trace benzene and remarkable hydrophobicity. The removal of trace benzene under humidity is still challenging in air treatment. Generally, MOFs have shown superior capture capacity than other adsorbents, but their uptake and hydrophobicity still need to be satisfied. Here, we reported a facile ion exchange method to obtain Al/Mn bimetallic MIL-53. The ion exchange of Mn under low temperatures could optimally maintain the structural integrities of obtained samples. Moreover, the in-situ monocarboxylic modulation could decrease the hydroxy content, improving the trace uptake while weakening the hydrophobicity. After ion exchange, the contents of OMS (open metal sites) and hydroxy both increased, upgrading the efficiency of trace benzene capture and improving the hydrophobicity under medium humidity. The optimal sample, Mn-A-25, performed well in trace benzene removal with 161 mg/g capacity under RH = 60 %, beyond two folds of MIL-53. Moreover, its hydrophobicity nearly equals that of MIL-53 (Q wet /Q dry = 0.96). The adsorption mechanism verified that increased adsorption enthalpy caused improved affinity on benzene. However, the adsorption was still driven by physical forces, which allowed for the visible desorption and superior regenerability of this adsorbent. [ABSTRACT FROM AUTHOR]

Liquid-liquid extraction is a well-established technique for removing hexavalent chromium (Cr(VI)) from aqueous solutions. However, conventional extractants often face limitations such as low extraction efficiency, poor reversibility, and organic vapor contamination due to their volatility. In this work, we prepared five types of hydrophobic deep eutectic solvents (HDESs) with excellent thermal stability by employing methyltrioctylammonium chloride (N 8881 Cl) as the hydrogen bond acceptor (HBA). We thoroughly investigated their thermophysical properties and performance in Cr(VI) extraction. The kinetic and thermodynamic results of the Cr(VI) extraction process revealed that these HDESs can achieve extraction equilibrium within 5 min, with increasing efficiency at higher temperatures. Among the tested HDESs, N 8881 Cl-MPD(1:1) exhibited an extraction efficiency of 99.9 % with a Cr(VI) concentration of 500 mg·L−1 at a low oil-to-water ratio of 1:50 (pH=2). This performance surpasses traditional extractants by more than four times. Analysis of extraction mechanisms revealed that ion exchange and electrostatic interactions primarily drive the extraction process. This research presents a sustainable alternative to the conventional organic solvent extraction of Cr(VI), offering a more efficient and environmentally friendly approach. [Display omitted] • Hydrophobic deep eutectic solvents (HDESs) for effective Cr(VI) extraction. • Up to 99.9 % extraction efficiency for Cr(VI) was obtained using HDESs. • Ion exchange and electrostatic interactions drive rapid Cr(VI) removal. • N 8881 Cl-MPD(1:1) maintains over 90 % Cr(VI) extraction efficiency across 14 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Submicron-scale ionic covalent organic polymer sheet-loaded agarose hydrogel blocks are prepared. • The mICOP-1/agarose composite hydrogel blocks show a stronger ability to adsorb iodine than powder porous materials. • Continuous dynamic removal of iodine in solution is achieved based on the processability of the composite hydrogel materials. In this work, monodisperse submicron-scale ionic covalent organic polymer (mICOP-1) sheets were obtained by dispersing ionic covalent organic polymer (ICOP-1) powders in ethanol and then subjected to low-speed centrifugation. The mICOP-1 sheets were dispersed into agarose hydrogels to obtain mICOP-1/agarose (mICOP-1@agar) composite hydrogel blocks. The composite hydrogel blocks can be used to adsorb I 3 − ion directly in aqueous solution or adsorb I 2 in cyclohexane after stepwise solvent exchange. As the agarose hydrogel provides the dispersed carrier of mICOP-1 sheets, the maximum adsorption capacity of mICOP-1 sheets in the composite hydrogel towards iodine is 1028.1 mg·g−1 in aqueous solution and 1152.5 mg·g−1 in cyclohexane, both of which are higher than that of ICOP-1 powders with 649.2 mg·g−1 in aqueous solution and 695.5 mg·g−1 in cyclohexane. Raman spectroscopy and X-ray photoelectron spectroscopy prove that the adsorption of I 3 − by mICOP-1@agar hydrogel blocks in aqueous solution is in the form of ion exchange, while in cyclohexane, it mainly relies on the formation of complexes between Cl− ions and I 2 , such as [I 2 Cl]− and [2I 2 Cl]−. Given that the plasticity of the mICOP-1@agar hydrogel materials, it can be made into hollow cylinder mounted on the peristaltic pump lines to achieve large-scale and continuous dynamic removal of iodine from solution. [ABSTRACT FROM AUTHOR]

Copper-exchanged zeolites have been subjected to several investigations because of their application as selective redox-active catalysts, and sensors. However, the ability of different types of zeolites to exchange Cu ions remains a matter of debate. All-atom molecular dynamics (MD) simulations, energy dispersive X-ray spectroscopy (EDS), and X-ray Fluorescence (XRF) methods have been used to evaluate the exchange of Cu(II) in mordenite and clinoptilolite zeolites using an aqueous method in the current study. Several parameters of copper ions have been measured for both types of zeolites, such as ion exchange ratio, mean square displacement (MSD), diffusion coefficient, and radial distribution function (RDF). These parameters were calculated for each zeolite system at different Cu ion concentrations in the feed solution. Copper exchange ratio and RDF analyses revealed a higher exchange ratio of copper ions in the mordenite framework. Analysis of the potential energy indicates the major adsorption sites for mordenite and clinoptilolite, which are located in the largest cavities of the zeolites. The adsorption energy of the mordenite sites (1.52 eV) was larger than that of clinoptilolite (1.28 eV). The stronger attraction between the copper ions and mordenite sites is consistent with the lower diffusion coefficients of the ions in this zeolite. The ion-exchange abilities of the zeolites were examined using EDS analysis. According to the EDS results, the mordenite zeolite exchanged more copper ions than the clinoptilolite, which is in agreement with the computational results. [Display omitted] • Mordenite framework adsorbs more copper ions compared with clinoptilolite. • Major adsorption site of zeolites is located at the largest cavity. • Adsorption energies of the mordenite sites are larger than those of clinoptilolite. • Copper exchange ability of mordenite and clinoptilolite was experimentally compared. [ABSTRACT FROM AUTHOR]

New formulations of unsupported tetrametallic catalysts derived from layered double hydroxides (LDH) compounds were synthesized by a constant pH coprecipitation method, characterized, and evaluated in the selective hydrodesulfurization (HDS) of thiophene in the presence of cyclohexene. The layered double hydroxides were prepared using terephthalate (C 8 H 8 O 2)2- as the interlayer anion with nominal aluminum molar fraction of 0.5, and nominal cobalt to MII (M = Zn or Mn) ratios of 0.2, 0.4 and 0.6. Molybdenum introduction in the LDH precursor was accomplished by an ion exchange process using the heptamolybdate anion. The calcined Mn samples showed a higher surface area than those obtained from Zn. The sulfidation was carried out in situ with a heating ramp up to 673 K and the catalysts were evaluated in a tubular flow reactor. The catalytic evaluation of Zn and Mn-based materials for simultaneous thiophene HDS and cyclohexene hydrogenation (HYD) was conducted at 573 K and 20 bar. The results show that the Zn-based unsupported catalysts synthesized here exhibited higher selectivity for the HDS reaction than an industrial one. [Display omitted] • New selective catalysts for naphtha hydrodesulfurization from hydrotalcite-type compounds were synthesized. • Textural and MoS 2 lamellae stacking differences were observed for materials with different divalent cations. • Catalysts containing zinc cation appear to be more selective for naphtha HDS. [ABSTRACT FROM AUTHOR]

• Indium ions were introduced into ZIF-67 by a feasible ion exchange method. • Defect-Rich In 2 S 3 /CoS 2 composite was obtained after the hydrothermal sulfidation. • The composite exhibited an excellent rate capability and cyclability stability. • The sodium storage mechanism of the In 2 S 3 /CoS 2 composite was explored. Aiming to accelerate sodium-ion transport kinetics and improve electrochemical cyclability of batteries, an In 2 S 3 /CoS 2 bimetallic sulfide heterostructure was synthesized as anodes of sodium-ion batteries (SIBs) in this paper by a feasible ion exchange and subsequent hydrothermal vulcanization technique based on a cobalt metal-organic skeleton (ZIF-67) precursor. As-prepared In 2 S 3 /CoS 2 composite exhibited an excellent rate capability of 453.8 mAh g-1 at 10 A g-1 and outstanding cyclability of 464.06 mAh g-1 after 600 cycles at 2 A g-1. The built-in electric filed between heterogeneous interface of In 2 S 3 and CoS 2 plays a dominant contribution on improvement of electronic conductivity and charge transfer kinetics. Beyond that abundant defects derived from ion exchange and nanocrystallization of composite particles also have a positive synergistic effect on inducing additional active centers for adsorption of Na+ and shortening ion transport distance for further accelerating reaction kinetics. Based on exploring conversion and alloying mechanism of In 2 S 3 /CoS 2 composite via ex situ XRD and TEM, high-performance SIBs with heterostructure bimetallic sulfide anodes may be a prospective strategy. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesise composite coagulants for simultaneous removal of Cs+ and Sr2+ ions. • Operating agitated tubular reactor (ATR) in scope of process intensification. • ATR provided maximum removal efficiency of > 96% Cs+ and > 99.9 % Sr2+. • Physical characterisation and pressure filtration analysis also performed. • Smaller specific cake resistances measured for composite flocs than BaSO 4. Composite coagulants were synthesised in both a batch system and an agitated tubular reactor (ATR) using natural clinoptilolite with barite (BaSO 4) co-precipitation for the intensified simultaneous removal of Cs+ and Sr2+ ions. Ideal plug-flow characterisation of ATR was initially assessed under 3 and 5 Hz oscillations, showing pseudo plug-flow behaviour at the higher rate. Composite flocs were characterised by SEM and size analysis, while dewaterability was also studied by sedimentation and pressure filtration. Aggregate sizes were smaller, but denser and more monodisperse from the ATR than in batch. Composite flocs also gave measured specific cake resistances > 10 × smaller than pure BaSO 4. The higher metal removal performance was achieved using the ATR for Cs+ (95.7%) and Sr2+ (99.9%) at 5 Hz oscillation. A further enhancement for Cs+ removal was achieved by introducing Ba2+ ions into ATR after Na 2 SO 4 addition, achieving > 96% Cs+ and > 99.9% Sr2+ removal. Overall, this study highlights that composite flocs outperform pure BaSO 4 in Cs+ and Sr2+ ion removal while achieving greater dewaterability and filterability. Additionally, we show the ATR effectively intensified the co-precipitation process, potentially reducing plant size and cost, making it a suitable process for modular nuclear cleanup and post-management operations. [Display omitted] [ABSTRACT FROM AUTHOR]

• A simpler and green process for synthesis of titanosilicate is developed. • Citric acid acts complexing agent for binding Ti in the gel. • Citric acid enables to use anatase or titanium iso propoxide as titanium source. • Prepared titanosilicate shows efficient exchange capability for both Cs+ and Sr2+. This manuscript reports an environmentally benign method for the synthesis of Engelhard titanosilicate (ETS-4) using titanium isopropoxide or anatase as titanium source and citric acid as complexing agent. Slow release of Ti from the hydroxide or oxide precursors through the citric acid complex plays crucial role in formation of titanosilicate. Characterizations of the prepared material were carried out by powder X-ray diffraction (XRD), Scanning Electron Microscope – Energy Dispersive X-ray spectroscopy (SEM-EDS), Thermogravimetric – Differential Thermal Analysis (TG-DTA) and ion exchange studies. Caesium and strontium exchange capacities of the synthesised ETS-4 were found to be 220 mg/g and 76.2 mg/g, respectively. The saturation exchange equilibrium was attained within 60 min. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-doping of copper and sulfur tunes the electronic structure of catalysts. • S 0.5 -Cu-CoP shows 65/139 mV overpotentials at 10 mA cm−2 in acidic/alkaline HER. • S 0.5 -Cu-CoP for total water solution test, 10 mA cm−2 requires only 1.55 V voltage. • In neutral medium, S 0.5 -Cu-CoP retains good HER performance and stability. Developing non-noble metal electrocatalysts with high activity and durability for the hydrogen evolution reaction (HER) is crucial for the efficient use of renewable resources and effective water splitting. The catalytic efficiency depends on the interaction among various primary constituent elements and dopants. However, achieving excellent HER performance across a wide pH range through synergistic effects among these species remains a challenge. A series of S, Cu co-doped CoP nanowire catalysts were prepared via a facile ion exchange strategy, demonstrating enhanced catalytic performance for HER over a wide pH range compared to single-doped CoP materials. The doping of S at the interface led to the transfer of electrons from Co atoms to Cu atoms, regulating the adsorption energy of intermediates and effectively accelerating the conversion of electrons and protons. Experimental results show that the optimized S 0.5 -Cu-CoP sample exhibits overpotentials of 65 and 139 mV at 10 mA cm−2 in acidic and alkaline HER, respectively, with Tafel slopes of 38.13 and 91.65 mV dec-1. Even in neutral medium, it still exhibits acceptable HER performance and catalytic stability. Additionally, the cell voltage is as low as 1.55 V to attain 10 mA cm−2 when employing S 0.5 -Cu-CoP and commercial nickel–iron foam as cathode and anode, respectively. This material possesses significant potential for energy-related applications, contributing to promote the further development of multifunctional electrode materials. [ABSTRACT FROM AUTHOR]

This study introduces a highly efficient tripolyphosphate -tethered cellulose sorbent for cadmium (Cd2⁺) removal from aqueous solutions. Characterization through FTIR and SEM revealed the material's structural properties. The sorbent achieved 99% Cd2⁺ removal even at a minimal dosage of 0.05 g. Optimal sorption occurred within the pH range of 4–6, influenced by the sorbent's weak acidic functional groups. Rapid kinetics, reaching equilibrium within a minute, and a high sorption capacity (up to 18.03 mg/g at 50 °C) were observed. Langmuir isotherm modeling confirmed monolayer sorption, and thermodynamic studies indicated a spontaneous, endothermic process with increased randomness at the solid-liquid interface. Selectivity studies demonstrated strong Cd2⁺ removal performance in the presence of competing ions, with minimal interference from monovalent ions but notable effects from divalent ions. The sorbent exhibited consistent reusability over multiple cycles. XPS analysis conclusively established an ion exchange mechanism between Cd2⁺ and negatively charged P 3 O 10 5− groups as the primary removal pathway. This research highlights the potential of TPP-tethered cellulose as a promising sorbent for effective Cd2⁺ remediation. [Display omitted] • Novel TPP-tethered cellulose sorbent for efficient Cd2⁺ removal. • Rapid kinetic, achieving equilibrium within a minute. • Effective Cd2⁺ removal in the presence of competing ions. • Regenerable sorbent for sustainable Cd2⁺ remediation. [ABSTRACT FROM AUTHOR]

Removal of silica from the borated water of primary systems of the nuclear power plant remains a long-term challenge for the industry. The same was tried to solve by membrane technology, however, membrane technology has its issues like generations of additional radioactive wastes. To address this issue a specialized hybrid resin for selective silica removal from borated water was prepared and tested for its efficiency at a pilot scale on an inventory taken from the spent fuel pool of an operational nuclear power plant having 2110 ppm boron and 400 ppb silica. The developed hybrid resin technique offers a simple and easy procedure to overcome several problems encountered in other methods of silica removal such as additional equipment, additional waste handling and maintenance. The validation shows that the application of the developed technique has a silica removal efficiency of 38% without affecting boron concentration. [ABSTRACT FROM AUTHOR]

Environmental remediation has emerged as a critical concern, with dye removal via adsorption being a particularly effective approach. This study demonstrates that appropriately synthesized Mg–Al-Layered Double Hydroxides (LDHs) exhibit exceptional adsorption capacities for anionic dyes. We investigate the impact of different washing media on the material's morphology, surface area, and adsorption capabilities. Notably, washing LDH with ethanol (LDHE) instead of water (LDHW) results in a significant reduction in particle size (70 and 200 nm), a nearly fourfold increase in surface area (197 and 52 m2/g), and a doubling of the maximum adsorption capacity for Congo red (CR) dye. The adsorption studies reveal that LDHE maintains its high CR adsorption efficiency across a variety of pH levels, in the presence of co-existing ions, and in simulated industrial effluent. The ion exchange interaction between the R–SO 3 - bonds in CR and the cationic layers of LDH (with the loss of carbonate anions) may be responsible for the adsorption. The rapid dye removal at lower concentrations and the impressive maximum adsorption capacity of 2452 mg/g (one of the highest ever reported for pure/single LDH systems) at higher concentrations highlight the potential of LDHE as a valuable adsorbent for large-scale applications. [Display omitted] • Role of washing media on the structural and dye adsorption properties of LDH. • Remarkable dye removal ability in both quality (∼99.9%) and quantity (2452 mg/g). • Robust performance with anions, diverse pH, and simulated industrial effluent. • Efficacy of adsorption explained via ion exchange and structural modification. [ABSTRACT FROM AUTHOR]