High Surface Area Research Articles

Magnetite Reduced Graphene Oxide/Ordered Mesoporous Carbon Nanocomposite as Effective Adsorbent for Removal of 2-Naphthol in Wastewater

Background: The wastewater released from various industries contains substantial amounts of organic compounds such as dyes and naphthols. However, naphthols are toxic to the environment and human health. So, it is essential to eliminate them, which will contribute to manufacturing and environmental management. Methods: In the work, an eco-friendly method is adapted to synthesize reduced graphene oxide (rGO) using Equisetum arvense plant extract as a strong reducing and stabilizing agent. Then, a hybrid nano adsorbent based on rGO and ordered mesoporous carbon (CMK-3) decorated with iron oxide nanoparticles (Fe3O4@rGO/CMK-3) was prepared as an adsorbent. We investigate the performance of Fe3O4@rGO/CMK-3 to remove 2-naphthol (2-NP). Results: The FE-SEM images exhibited spherical magnetite nanoparticles with sizes ranging from 31 to 47 nm on composite. Efficient removal (90%) of 2-NP from aqueous solution is demonstrated using high surface area Fe3O4@rGO/CMK-3 (initial concentration of 2-NP: 10 mg mL-1, pH: 5.0, time: 30 min, and amount of adsorbent dosage: 3 mg mL-1). The high surface area of Fe3O4@rGO/CMK-3, hydrogen binding, π-π stacking interaction between the benzene rings of 2-NP and graphitic skeleton of hybrid adsorbent facilitate the adsorption of 2-NP on the Fe3O4@rGO/CMK-3. The 2NP removal capacity by (Fe3O4@rGO/CMK-3) showed a significant decrease during five successive cycles. Conclusions: These results promise the potential of high surface area (Fe3O4@rGO/CMK-3) for efficient removal of 2-NP for wastewater treatment.

Emerging Technologies for Sensitive Detection of Organophosphate Pesticides: A Review

Abstract: The use of organophosphate pesticides (OPPs) in agricultural practices improves crop yield and controls pests, but their indiscriminate use and persistence in the environment pose significant health risks. Therefore, it has become increasingly important to develop reliable and efficient detection methods for OPPs to ensure food safety and monitor their presence. In recent years, OPP detection methods have undergone significant advancements. Sensors such as colorimetric, fluorescence, electrochemical, and impedometric offer several advantages over traditional methods, such as high sensitivity, selectivity, and portability. The purpose of this review paper is to provide an overview of recent developments in OPP detection methods. The paper discusses the different types of sensors that are available for the detection of OPPs, as well as their advantages and disadvantages. Many electrochemical methods have been employed to investigate OPP detection, including voltammetry, impedance spectroscopy, and amperometry. The integration of nanomaterials, such as carbon nanotubes, graphene, and metal nanoparticles, has significantly enhanced the performance of electrochemical sensors by providing high surface area, enhanced electron transfer, and specific analyte interactions. Furthermore, the review discusses the utilization of biomolecules, such as enzymes and aptamers, as recognition elements in sensor platforms for selective and sensitive OPP detection. The incorporation of these biomolecules offers high specificity and enables real-time monitoring of OPP residues in food samples and environmental matrices. It emphasizes the importance of continued research and development to optimize detection methods, improve sensor performance, and make these technologies more widely accessible for effective monitoring and control of OPP contamination in various domains.

A Sustainable and Cost-Effective Nitrogen-Doped Three-Dimensional Porous Carbon for High-Performance Lithium-Sulfur Batteries.

Affordable clean energy is one of the major sustainable development goals that can transform our world. At present, researchers are working to develop cheap electrode materials to develop energy storage devices, the Lithium-sulfur (Li-S) battery is considered a promising energy storage device owing to its excellent theoretical specific capacity and energy density. Herein, utilizing the ramie degumming waste liquid as raw materials, after freeze-drying and high-temperature calcination, a sustainable and cost-effective three-dimensional (3D) porous nitrogen-doped ramie carbon (N-RC) was synthesized. The N-RC calcined at 800 °C (N-RC-800) shows a superior high specific surface area of 1491.85 m2 ⋅ g-1 and a notable high pore volume of 0.90 cm3 ⋅ g-1. When employed as a sulfur host, the S@N-RC-800 cathode illustrates excellent initial discharge capacity (1120.6 mAh ⋅ g-1) and maintains a reversible capacity of 625.4 mAh ⋅ g-1 after 500 cycles at 1 C. Simultaneously, the S@N-RC-800 cathode also shows excellent coulombic efficiency and ideal rate performance. Such exceptional electrochemical performance of S@N-RC-800 can be primarily attributable to N-RC's high specific surface area, high porosity, and abundant polar functional groups. This green and low-cost synthesis strategy offers a new avenue for harnessing the potential of waste biomass in the context of clean energy storage.

Engineering hierarchical snowflake-like multi-metal selenide catalysts anchored on Ni foam for high-efficiency and stable overall water splitting.

The development of excellent bifunctional electrocatalysts is an effective way to promote the industrial application of electrolytic water. In this work, a free-standing W-doped cobalt selenide (W-CoSe300/NF) electrocatalyst with a snowflake-like structure supported on nickel foam was prepared by a hydrothermal-selenization strategy. Benefiting from the high specific surface area of the 3D snowflake-like structure and the regulation of tungsten doping on the electronic structure of the metal active center, W-CoSe300/NF shows remarkable electrocatalytic water decomposition performance. In 1.0 M KOH, the W-CoSe300/NF electrocatalyst achieved an efficient HER and OER at a current density of 50 mA cm-2 with overpotentials as low as 84 mV and 283 mV, respectively. More importantly, W-CoSe300/NF acts as both the anode and cathode of the electrolytic tank, requiring only a potential of 1.54 V to obtain 10 mA cm-2 and can operate continuously for more than 120 hours at this current density. This study proposes a new way for the design of high efficiency and affordable bifunctional electrocatalysts.

Recent Progress in Using Covalent Organic Frameworks to Stabilize Metal Anodes for Highly-Efficient Rechargeable Batteries.

Alkali metals (Li, Na, and K) and multivalent metals (Zn, Mg, Ca, and Al) have become star anodes for developing high-energy-density rechargeable batteries due to their high theoretical capacity and excellent conductivity. However, the inevitable dendrites and unstable interfaces of metal anodes pose challenges to the safety and stability of batteries. To address these issues, covalent organic frameworks (COFs), as emerging materials, have been widely investigated due to their regular porous structure, flexible molecular design, and high specific surface area. In this minireview, we summarize the research progress of COFs in stabilizing metal anodes. First, we present the research origins of metal anodes and delve into their advantages and challenges as anodes based on the physical/chemical properties of alkali and multivalent metals. Then, special attention has been paid to the application of COFs in the host design of metal anodes, artificial solid electrolyte interfaces, electrolyte additives, solid-state electrolytes, and separator modifications. Finally, a new perspective is provided for the research of metal anodes from the molecular design, pore modulation, and synthesis of COFs.

Recent Progress in Using Covalent Organic Frameworks to Stabilize Metal Anodes for Highly‐Efficient Rechargeable Batteries

AbstractAlkali metals (e.g. Li, Na, and K) and multivalent metals (e.g. Zn, Mg, Ca, and Al) have become star anodes for developing high‐energy‐density rechargeable batteries due to their high theoretical capacity and excellent conductivity. However, the inevitable dendrites and unstable interfaces of metal anodes pose challenges to the safety and stability of batteries. To address these issues, covalent organic frameworks (COFs), as emerging materials, have been widely investigated due to their regular porous structure, flexible molecular design, and high specific surface area. In this minireview, we summarize the research progress of COFs in stabilizing metal anodes. First, we present the research origins of metal anodes and delve into their advantages and challenges as anodes based on the physical/chemical properties of alkali and multivalent metals. Then, special attention has been paid to the application of COFs in the host design of metal anodes, artificial solid electrolyte interfaces, electrolyte additives, solid‐state electrolytes, and separator modifications. Finally, a new perspective is provided for the research of metal anodes from the molecular design, pore modulation, and synthesis of COFs.

Heterogeneous Porous Synergistic Photocatalysts for Organic Transformations.

Recent interest has surged in using heterogeneous carriers to boost synergistic photocatalysis for organic transformations. Heterogeneous catalysts not only facilitate synergistic enhancement of distinct catalytic centers compared to their homogeneous counterparts, but also allow for the easy recovery and reuse of catalysts. This mini-review summarizes recent advancements in developing heterogeneous carriers, including metal-organic frameworks, covalent-organic frameworks, porous organic polymers, and others, for synergistic catalytic reactions. The advantages of porous materials in heterogeneous catalysis originate from their ability to provide a high surface area, facilitate enhanced mass transport, offer a tunable chemical structure, ensure the stability of active species, and enable easy recovery and reuse of catalysts. Both photosensitizers and catalysts can be intricately incorporated into suitable porous carriers to create heterogeneous dual photocatalysts for organic transformations. Notably, experimental evidence from reported cases has shown that the catalytic efficacy of heterogeneous catalysts often surpasses that of their homogeneous analogues. This enhanced performance is attributed to the proximity and confinement effects provided by the porous nature of the carriers. It is expected that porous carriers will provide a versatile platform for integrating diverse catalysts, thus exhibiting superior performance across a range of organic transformations and appealing prospect for industrial applications.

Single-step, in-situ fabrication of flower-like NiCuMn hybrid oxyhydroxide electrodes for enhanced supercapacitor performance

The rational design of highly active and low-cost electrode material is very promising for energy storage applications. The development of supercapacitors with high energy/power density is an imperative and challenging research objective. Herein, we report a highly facile synthesis approach for developing unique nano-porous hybrid NiCuMn oxyhydroxide architecture with remarkable electrochemical energy storage characteristics. The process involves dealloying of Ni15Cu15Mn70 alloy in an oxygen rich environment, resulting in a uniform 3-dimensional flower like morphology. The dealloyed electrode demonstrates ultra-high specific capacitance of 4110 F cm−3 at a high current density of 20 mA cm−2. A symmetric device exhibits a high volumetric capacitance of 365 F cm−3 at a current density of 10 mA cm−2 with a large potential window of 1.7 V. Even at very high-power density of 850 W l−1, the device exhibits a high energy density of 146 Wh l−1 along with remarkable cyclic stability of 95.4% after 10 000 cycles. The superior performance of nano-porous hybrid NiCuMn oxyhydroxide architecture was attributed to its unique microstructure that provides high surface area, and marginal internal resistance ensuring rapid charge transport.

Biotemplated Fe/La-co-doped TiO2 for photocatalytic depth treatment of compressed leachate from refuse transfer station.

Compressed leachate is a contaminated liquid containing various organic and inorganic pollutants produced in municipal refuse transfer stations, which pollute soil and groundwater, posing serious risks to the environment and human health. The Environmental Technology Co., Ltd. (Shenzhen, Guangdong Province, South China) treated compressed leachate obtained from a refuse transfer station. The chemical oxygen demand (COD) (641.2mg/L) of treated compressed leachate did not meet the wastewater quality standards in China for discharge into municipal sewers (COD ≤ 500mg/L) and the company's design discharge requirements (COD ≤ 400mg/L). Therefore, their further in-depth treatment is necessary. To this end, waste tobacco leaves were used as the biotemplate herein, and Fe/La-co-doped TiO2 (xFe,yLa)-TTiO2(g) was synthesized using a solvothermal-assisted biotemplating method. The photocatalytic depth treatment of compressed leachate was performed under simulated solar light using the prepared catalysts. After (3Fe,3La)-TTiO2(g) treatment, the COD of the leachate decreased from 641.2 to 280.1mg/L, and the COD removal rate was 1.2, 1.1, and 1.6 times higher than that of pure Fe-doped, La-doped and non-biological template TiO2, respectively. Characterization confirmed that the biological template endowed the catalyst with a unique morphology and high specific surface area. Its rich activity sites are conducive to enhancing the adsorption capacity of pollutants and providing an ideal place for photocatalytic reactions. Co-doping with iron and lanthanum ions altered the band structure of TiO2 and promoted the interconversion of Fe3+/Fe2+ and La3+/La2+ during photocatalysis. First-principles density functional theory simulations demonstrated that co-doping Fe and La in TiO2 created impurity levels that facilitated the transfer of photogenerated electrons. This study provides a new purification pathway for the depth treatment of compressed leachate.

Flexible aqueous Cr-ion hybrid supercapacitors with remarkable electrochemical properties in all climates.

The integration of hostless battery-like metal anodes for hybrid supercapacitors is a realistic design method for energy storage devices with promising future applications. With significant Cr element deposits on Earth, exceptionally high theoretical capacity (1546 mAh g-1), and accessible redox potential (-0.74 V vs. reversible hydrogen electrode) of Cr metals, the design of Cr anodes has rightly come into our focus. This work presents a breakthrough design of a flexible Cr-ion hybrid supercapacitor (CHSC) based on a porous graphitized carbon fabric (PGCF) substrate prepared by K2FeO4 activation. In the CHSC device, PGCF acts as both a current collector and cathode material due to its high specific surface area and superior conductivity. The use of a highly concentrated LiCl-CrCl3 electrolyte with high Cr plating/stripping efficiency and excellent antifreeze properties enables the entire PGCF-based CHSC to achieve well-balanced performance in terms of energy density (up to 1.47 mWh cm-2), power characteristics (reaching 9.95 mW cm-2) and durability (95.4% capacity retention after 30,000 cycles), while realizing it to work well under harsh conditions of -40 °C. This work introduces a new concept for low-temperature energy storage technology and confirms the potential application of Cr anodes in hybrid supercapacitors.

Wood-Structured Nanomaterials as Highly Efficient, Self-Standing Electrocatalysts for Water Splitting.

Electrocatalytic water splitting (EWS) driven by renewable energy is widely considered an environmentally friendly and sustainable approach for generating hydrogen (H2), an ideal energy carrier for the future. However, the efficiency and economic viability of large-scale water electrolysis depend on electrocatalysts that can efficiently accelerate the electrochemical reactions taking place at the two electrodes. Wood-derived nanomaterials are well-suited for serving as EWS catalysts because of their hierarchically porous structure with high surface area and low tortuosity, compositional tunability, cost-effectiveness, and self-standing integral electrode configuration. Here, recent advancements in the design and synthesis of wood-structured nanomaterials serving as advanced electrocatalysts for water splitting are summarized. First, the design principles and corresponding strategies toward highly effective wood-structured electrocatalysts (WSECs) are emphasized. Then, a comprehensive overview of current findings on WSECs, encompassing diverse structural designs and functionalities such as supported-metal nanoparticles (NPs), single-atom catalysts (SACs), metal compounds, and heterostructured electrocatalysts based on engineered wood hosts are presented. Subsequently, the application of these WSECs in various aspects of water splitting, including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall water splitting (OWS), and hybrid water electrolysis (HWE) are explored. Finally, the prospects, challenges, and opportunities associated with the broad application of WSECs are briefly discussed. This review aims to provide a comprehensive understanding of the ongoing developments in water-splitting catalysts, along with outlining design principles for the future development of WSECs.

Crosslinked Polydiallyldimethylammonium Chloride Adsorbent for the Selective Separation of Rhenium Ions from Pregnant Leach Solutions.

The depletion of valuable mineral reserves has rendered effluents generated from mining and industrial processing activities a promising resource for the production of precious elements. The synthesis and improvement of new adsorbents to extract valuable compounds from industrial wastes and pregnant leach solutions, besides increasing wealth, can play a significant role in reducing environmental concerns. In this work, a new and low-cost adsorbent for the selective extraction of rhenium (perrhenate ions, ReO4-) was synthesized by the free-radical polymerization (FRP) of a diallyl dimethylammonium chloride monomer (quaternary amine) in the presence of a crosslinker. Various methods were employed to characterize the polymeric adsorbent. The results revealed that the designed polymeric adsorbent had a high surface area and pores with nano-metric dimensions and a pore volume of 6.4 × 10-3 cm3/g. Four environments-single, binary, multicomponent, and real solutions-were applied to evaluate the adsorbent's performance in the selective separation of Re. Additionally, these environments were used to understand the behavior of molybdenum ions, the primary competitors of perrhenate ions in the ion exchange process. In competitive conditions, using variations in qe,mix/qe, an antagonism phenomenon (qe,mix/qe < 1) occurred due to the inhibitory effect of surface-adsorbed molybdenum ions on the binding of the perrhenate ions. However, across all conditions, the separation values for Re were higher than those for the other studied elements (Mo, Cu, Fe).

On the CO2 Harvesting from N2 Using Grazyne Membranes.

The separation of carbon dioxide (CO2) from nitrogen (N2) is at the core of any global warming remediation technology aimed at reducing the CO2 content in the atmosphere. Chemical membranes designed to differentially permeate both molecules have become quite appealing due to their simple use, although many membrane-based separations stand out as a promising solution for CO2 separation. These are environmentally friendly, with high active surface areas, compact design, easy to maintain and cost-effective, although the field is still growing due to the difficulties in the CO2/N2 separation. The present study poses grazynes, two-dimensional C-based materials with sp and sp2 C atoms, aligned along stripes, as suited membranes for the CO2/N2 separation. The combination of density functional theory (DFT) and molecular dynamics (MD) simulations allow tackling the energetics, kinetics, and dynamics of the membrane effectiveness of grazynes with engineered pores for such a separation in a holistic fashion. The explored grazynes are capable of physisorbing CO2 and N2, thus avoiding material poisoning by molecular decoration, while the diffusion of CO2 through the pores is found to be rapid, yet easier than that of N2, in the rate order of the s-1 in the 100-500 K temperature range. In particular, low-temperature CO2 separation even for CO2 contents below 0.5 % are found for [1],[2]{2}-grazyne when controlling the membrane exposure contact to the gas mixture, paving the way for exploring and using grazynes for air CO2 remediation.

Unlocking the Charge-storage Potential of a Phenanthraquinone-based Two-dimensional Covalent Organic Framework (2D COF).

The high surface area, open pore-structure and atomic-level organization inherent in many covalent organic frameworks (COFs) make them an attractive polymer platform for developing functional materials. Herein, a chemically robust 2D COF (TpOMe-DAPQ COF) containing phenanthraquinone moieties was prepared by condensing 2,4,6-trimethoxy-1,3,5-benzenetricarbaldehyde (TpOMe) and 2,7-diamino-9,10-phenanthraquinone (DAPQ) using the convenient mechanochemical method. The poor charge-storage capacity of the pristine TpOMe-DAPQ COF was substantially improved by first investigating its redox-site accessibility (RSA) using different conductivity-enhancement methods, and then optimizing the amount of EDOT needed to perform an in-situ polymerization. The resulting composite (0.4EDOT@TpOMe-DAPQ) was characterized and its enhanced charge-storage capabilities enabled it to be used as an anode material in an aqueous Mn beaker-cell battery capable of delivering 0.76 V. This work outlines the rational design approach used to develop a functional charge-storage material utilizing a COF-based polymerization platform.

Fabrication and characterization of Sb-doped MXene prepared by hydrothermal method for use as a sensing electrode for heavy metal detection

MXene, a two-dimensional material with favorable physicochemical characteristics, has demonstrated outstanding efficiency in a wide range of applications because of their superior properties, such as higher surface area and conductivity, and facile surface modification. In this study, antimony (Sb) doped MXenes were synthesized via a simple hydrothermal method, employing various Sb concentrations ranging from 5%w/w to 25%w/w. The successful preparation of the Sb-doped MXene (Sb@MXene) was confirmed by an X-ray diffraction (XRD) method. Physical morphologies examined through field-emission scanning electron microscopy (FE-SEM) depict the presence of Sb nanoparticles with the size of about 80 nm on the surface and interlayer of MXenes. The Sb@MXene composites demonstrated significant potential as electrochemical sensing materials for heavy metal detection. Both 5%Sb@MXene and 25%Sb@MXene composites were prepared as the screen-printed electrode (SPE) materials via drop-casting method to sense Pb2+, Cd2+, and Zn2+. The 25%Sb@MXene SPE show the highest sensitivity toward Pb2+(3.62 μA∙ppm‒1), Cd2+(2.53 μA∙ppm‒1), and Zn2+ (0.90 μA∙ppm‒1) solution, compared with that of 5%Sb@MXene SPE. This work not only demonstrates a simple preparation of Sb@MXene, but also applies the hybrid materials in electrochemical sensing application.

Synthesis of titanium dioxide nanoparticles for enhanced photocatalytic activity in the degradation of emerging contaminants

The study investigates the impact of calcination temperature and the addition of H2O2 on the properties of TiO2 synthesized through the sol–gel method. The photoactivity of TiO2 in degrading Paracetamol revealed that the optimal calcination temperature was identified as 350 °C, attributed to a smaller crystallite size, higher surface area, and the anatase phase. Adding H2O2 during TiO2 preparation influenced the porous structure and photoactivity. Transmission electron microscopy revealed nanoparticles with average sizes of 12 ± 3 nm. TiO2 prepared with H2O2 showed improved photoactivity, possibly due to surface modifications, removing 98 % of Paracetamol. The addition of scavengers influenced the degradation efficiency, confirming the involvement of reactive species such as hydroxyl radicals. In summary, the study provides valuable insights into the influence of calcination temperature and H2O2 addition on the properties and photoactivity of TiO2, emphasizing the importance of optimal synthesis conditions for enhanced performance in environmental remediation applications.

Biochar-mediated synthesis of ZSM-5 zeolite for the methanol-to-olefins reaction

The present study reports the successful synthesis of ZSM-5 zeolites with high external specific surface area by using biochar as a hard template. The physicochemical properties of the biochars (originated from grass, tea and lignin) were studied using XRD, SEM EDX, FTIR and other characterization techniques. The results showed that biochars obtained from different plants, due to the differences in morphology, particle size, composition and surface functional groups, led to significant effects on the morphology and acidity of the zeolite crystals. These ZSM-5 zeolites exhibited a significantly improved performance in the Methano-To-Olefins (MTO) reaction. Indeed, the catalyst lifetime of parent ZSM-5 started to decline after 6 h, whilst ZSM-5 modified by Grass-C only suffered a loss in conversion after 10 h on stream (at 400 °C, WHSV=8 h−1).

Leonardite humic acid activated carbon/MnO\(_{2}\) composite nanostructures for supercapacitors

Abstract This work reports the preparation and electrochemical studies of activated carbon derived from leonardite humic acid composited with MnO2 for supercapacitors. Activated carbon contains high conductivity, high specific surface area, and accommodates large volume expansion/contraction during charging/discharging process. Meanwhile, MnO2 has very high theoretical specific capacity (1370 F∙g‒1). Their composite could significantly improve both the storage performance and cycle stability of supercapacitors. Moreover, humic acid from leonardite was selected to add value to this waste and reduce environmental pollution. By varying the carbonization temperature (500℃ to 800℃), the prepared samples carbonized at 800℃ exhibited fascinating properties. The oxidation state of Mn ions was in the mixed state of Mn+2 (41.2%) and Mn+2, +3 (52.8%). A gravimetric capacitance of 329 F∙g‒1 and 294 F∙g‒1 were observed at 2 mVs-1 and 0.5 Ag-1, respectively. The remaining gravimetric capacitance of 193 F∙g‒1 was evaluated at 1000 cycles, indicating its high cycle performance. Moreover, the gravimetric energy of 37.51 Wh∙kg‒1 and gravimetric power of 272.96 W∙kg‒1 were observed. When combined, the interesting electrochemical properties of leonardite humic acid-activated carbon/MnO2 composite nanostructures make them important options for supercapacitor application.

Optimizing electrochemical power generation: Harnessing synergies and surface innovation in NiTe-modified MOF nanoarchitectures

Metal-organic frameworks (MOFs) are considered potential electrocatalysts due to their high specific surface area (SSA) and the facilitation of efficient synergistic interactions. In this work, we have implemented a simple and cost-effective surface modification approach to design an efficient electrocatalyst for energy-conversion technologies, specifically water splitting. This work focuses on engineering a novel NiTe functionalized MOF structure wherein NiTe within the MOF channels is the core material, intricately intertwined with highly dispersed Ni particles enveloped by Ni MOF. This fusion of MOFs and NiTe within a designed configuration produces an efficient electrocatalyst with synergistic and surface interface effects and demonstrates bifunctional activity for water splitting. Among the prepared catalysts, one of the resulting catalysts (named Ni MOF/Ni/Ni10Te8) exhibits a low overpotential of 99 mV for the hydrogen evolution reaction (HER) and 180 mV for the oxygen evolution reaction (OER), both benchmarked against RHE @10 mA cm−2. This performance remains steady, with a stability of 99 % after 15 h of continuous operation. Furthermore, the Ni MOF/Ni/Ni10Te8 catalyst also operates in seawater electrocatalysis, requiring a low overpotential of 440 mV at 10 mA cm−2 to produce 70 mL of hydrogen and 34 mL of oxygen. Equally noteworthy are the Faradaic efficiencies achieved, with hydrogen production at 95.7 % and oxygen production at 92.9 %. Developing efficient and economically viable electrocatalysts like the Ni MOF/Ni/NiTe catalyst will advance a cleaner and more sustainable future.

Evaluating SiO2/Al2O3/poly(acrylic acid-co-glycidyl methacrylate) composite as a novel adsorbent for cobalt(II) radionuclides

Abstract A novel SiO2/Al2O3/poly(acrylic acid-co-glycidyl methacrylate), SiO2/Al2O3/P(AA-co-GMA), composite was synthesized and evaluated for its effectiveness in adsorbing Co(II) ions from aqueous solutions. The composite was analyzed using various techniques including FTIR, SEM, TGA, DTA, and XRD. The composite displays a high specific surface area of 17.451 m2/g, exceeding that of the corresponding copolymer, which measures 0.236 m2/g. Batch adsorption experiments were conducted to investigate the factors influencing the adsorption capacity of the composite for Co(II) ions. In the pH experiments, it was found that at a solution pH of 3.4, the P(AA-co-GMA) copolymer alone showed limited capability in adsorbing Co(II) ions, achieving only 3.82 mg/g. However, upon integration of SiO2/Al2O3 into the polymer matrix, the composite exhibited a significantly enhanced adsorption capacity of 103.54 mg/g. The adsorption process followed a pseudo-second-order kinetic model and attained equilibrium within 60 min. The Langmuir isotherm model was found to best describe the adsorption behavior, with a maximum adsorption capacity of 217.86 mg/g. The adsorption of Co(II) was significantly affected by the ionic strength, especially with Al3+ displaying a more pronounced impact on the adsorption of Co(II) ions compared to Na+, Ca2+, and Mg2+. Thermodynamic studies indicate that the adsorption process was spontaneous and endothermic. Overall, the SiO2/Al2O3/P(AA-co-GMA) composite material displayed significant adsorption ability for Co(II) ions, making it a suitable option for further development as an effective adsorbent in water treatment applications.