Bishnupada Mandal

Owing to its severe toxicity and environmental persistence, Pb2+ poses a critical threat among waterborne heavy-metal contaminants. To address this challenge, we developed a bimetallic cerium/molybdenum metal–organic framework (CM(1:1)) via an in situ approach for rapid, efficient, and selective Pb2+ removal. The composite exhibited a high removal efficiency, reducing Pb2+ concentrations below the WHO limit within 1 (∼2.83 ppb) and 3 min (∼2.57 ppb) for 10 and 100 ppm, respectively. The adsorption behavior followed the Langmuir isotherm most closely, yielding a maximum uptake capacity of 991.67 ± 20.25 mg/g and confirming a monolayer adsorption mechanism. The closer the conformity with the pseudo-first-order model, the more consistent it is with a fast surface-controlled process. High-resolution XPS detected Pb-bound surface species, accompanied by slight shifts in O 1s and C 1s signals, confirming the involvement of oxygenated groups in Pb2+ uptake. Thermodynamic parameters demonstrated that the Pb2+ uptake was spontaneous and exothermic. The composite also exhibited remarkable selectivity toward Pb2+ in the presence of competing ions (Na+, K+, Mg2+, Cd2+, Zn2+, and Ni2+) and maintained more than 80% removal efficiency through the sixth regeneration cycle. To complement the experimental findings, we constructed an artificial neural network (ANN) predictor for Pb2+ adsorption based on key operating variables (contact time, initial pH, initial metal ion concentration, adsorbent dose, and temperature). The model employed a three-layer backpropagation multilayer perception (MLP) trained with the Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization algorithm, and achieved high predictive accuracy (R2 = 0.993) with low prediction error, demonstrating strong consistency between experimental and modeled outcomes and supporting process optimization. These results highlight CM(1:1) as a promising, durable adsorbent for Pb2+ remediation and advanced wastewater treatment.

This study reports the preparation of MIL-100(Fe)-GO composites by a one-pot synthesis approach at room temperature, assisted by ultrasonication. The synthesized MIL-100(Fe)-GO composites were utilized as a filler for the preparation of a sulfonated polyether ether ketone (SPEEK)-based proton exchange membrane (PEM). The in situ development of MIL-100(Fe) on GO creates a strong interaction between GO and MIL-100(Fe), which enhances the surface roughness (confirmed from the AFM study) of the SPEEK membrane with its incorporation as a filler. The resulting SPEEK membrane containing MIL-100(Fe)-GO exhibits a hydrophobic-hydrophilic phase-separated structure, delivering impressive performance as a PEM. Notable characteristics include high proton conductivity, low methanol crossover, high selectivity, and high power density compared with pure SPEEK membranes. Specifically, the composite membranes, particularly SPEEK with 3% (w/w) MIL-100(Fe)-GO (SMGO3), demonstrate reduced methanol crossover (0.22 × 10^-6 cm²/s) and enhanced proton conductivity (10.90 mS/cm), resulting in superior selectivity of 4.9 × 10⁴ S·s·cm^-3 over Nafion-117 (0.65 × 10⁴ S·s·cm^-3) benchmark membranes. Durability experiments and Fenton's test for the oxidative stability of the SMGO3 membrane were also performed. In direct methanol fuel cell applications, the SPEEK/MIL-100(Fe)-GO membrane significantly outperforms pristine SPEEK, indicating its potential as a promising candidate for PEMs.

High-performing zeolite materials for carbon dioxide capture are promising for applications such as flue gas CO₂ capture. Potassium carbonate–loaded zeolites can offer a plethora of benefits. In this work, for the first time, zeolite-Y impregnated with K₂CO₃ was studied as a gas adsorbent (CO₂, CH₄, and N₂) and characterized using TGA (thermogravimetric analyzer), XRD, BET, FTIR, FETEM (Field-Emission Transmission Electron Microscope), and XPS. The effect of carbonate loading, temperature, and pressure was particularly targeted and assessed. Accordingly, for a variation in K₂CO₃ loading from 5 to 15 wt.%, the CO₂ adsorption capacity reduced from 3.61 to 1.73 mmol g⁻¹ in the synthesized adsorbents. Among all the cases, KYZC10 exhibited very good cyclic adsorption–desorption performance and thermal stability. Further equilibrium modeling studies indicate that the stable and optimally K₂CO₃-loaded adsorbent (KYZC10) demonstrates effective adsorption isotherm behavior, making it suitable for different temperature variation processes in commercial carbon dioxide capture applications. The KYZC10 adsorbent’s stable performance at varying temperatures contributes to its enhanced economic feasibility. This study also used the ideal adsorbed solution theory (IAST) to predict CO₂ selectivity over other gases (CH₄ and N₂). Graphical Abstract

We present the synthesis and characterisation of three Ce-based metal–organic frameworks (Ce–MOFs) using fumaric acid (Fu), terephthalic acid (BDC), and trimesic acid (H₃BTC) as linkers. The use of different linkers influenced the size of the MOF particles, surface area, crystallinity, and microporous structure. The successful implementation of Ce–Fu, Ce–BDC, and Ce–H₃BTC MOFs for fluoride ion removal from wastewater was carried out, in which Ce–Fu MOFs exhibited a maximum adsorption capacity (AC) of 64.2 mg g⁻¹. The study also reveals that the use of ultrasound as a mediator for adsorption study over conventional method gives rapid adsorption rate, in which 85% of the fluoride uptake took place just in 10 min and achieved maximum AC in 30 min. The kinetics data were most accurately explained by the pseudo-second-order model (PSO). The existence of co-ions such as NO₃⁻, Cl⁻, HCO₃⁻, SO₄²⁻, Br⁻, CO₃²⁻, and PO₄³⁻ has a substantial effect on fluoride removal. The mechanism between the fluoride ions and the MOF surface took place via the electrostatic force and the ion exchange process, confirmed using X-ray photoelectron spectroscopy (XPS) and delsa nano. The material is sustained its relatively higher F⁻ ions removal efficiency up to the five cycles. This research might help in the development of novel microporous Ce-based MOFs since it possesses a highly stable crystalline structure in water, suggesting a promising role in aqueous applications. Graphical Abstract

Growing concern about global warming and greenhouse effects has led to persistent demands for increased energy efficiency and reduced carbon dioxide emissions. As a result, energy-intensive processing of carbon dioxide separation became imperative. Accordingly, energy-efficient, economically viable carbon dioxide separation technologies are sought as carbon dioxide capture options for future industrial process schemes. The article provides an overview of current technology for the separation of carbon dioxide, specifically focusing on adsorption. In this study, amine-loaded Zeolite-Y adsorbents were evaluated to enhance carbon dioxide adsorption capacity through synthesis, characterization, and the adsorption of carbon dioxide, within the context of current trends in separation technology. This study aims to study the ability of amine-loaded Zeolite-Y to adsorb carbon dioxide using three different loadings ethanolamine, diethanolamine, and triethanolamine. The amine-loaded materials were characterized by various technologies, including X-ray diffraction pattern (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and field emission scanning electron microscope (FESEM) studies. The study suggests that monoethanolamine-loaded Zeolite-Y is a promising and cost-effective adsorbent for carbon dioxide adsorption in comparison to other synthesized amine-loaded adsorbents. The adsorbent has been able to adsorb carbon dioxide in the range of 1.14–2.26 mmol g⁻¹ at 303 K and 1 bar for a loading of 1, 5, and 10 wt.% amine groups.