Excellent Surface Area Research Articles

Electrochemical measurement of morphine using a sensor fabricated from the CuS/g-C3N5/Ag nanocomposite

Morphine, as one of the most important narcotic drugs, significantly affects the nervous system and increases euphoria, which raises the likelihood of its misuse. Therefore, its measurement is of great importance. In this work, a new electrochemical sensor based on a nanocomposite of CuS/g-C3N5/AgNPs was developed for modifying Screen printed carbon electrodes (SPCEs) and used for the measurement of morphine through cyclic voltammetry and differential pulse voltammetry. Various analytical methods initially characterized the nanocomposite. The prepared sensor, which also has an extensive surface area, achieved a detection limit of 0.01 µM for morphine in a concentration range of 0.05–100 µM at pH 7. Besides its excellent capability in measuring morphine in real samples, the sensor exhibits good stability, reproducibility, and repeatability. The presence of CuS, due to its excellent high surface area alongside silver nanoparticles, leads to an increase in the conductivity of the g-C3N5 modified electrode, resulting in an increased oxidative current of morphine at the surface of the prepared sensor. Therefore, measuring low concentrations of morphine with this sensor was made possible. Additionally, measuring morphine without interference from various species is a strong point of the electrochemical sensor for morphine detection, and combined with the simplicity and ease of the method, it allows for morphine measurements to be conducted in the shortest possible time.

Dendrite-Free Lithium Batteries Enabled by an Artificial High-Dielectric Biopolymer Interface Layer.

Lithium (Li) metal batteries face challenges, such as dendrite growth and electrolyte interface instability. Artificial interface layers alleviate these issues. Here, cellulose nanocrystal (CNC) nanomembranes, with excellent mechanical properties and high specific surface areas, combine with polyvinylidene-hexafluoropropylene (PVDF-HFP) porous membranes to form an artificial solid electrolyte interphase (SEI) layer. The porous structure of PVDF-HFP equalizes the electric field near metallic lithium surfaces. The high mechanical modulus of CNC (6.2 GPa) effectively inhibits dendrite growth, ensures the uniform flow of lithium ions to the lithium metal electrode, and inhibits the growth of lithium dendrites during cycling. The synergy of high polarity β-phase poly(vinylidene fluoride) (PVDF) and CNC provides over 1000 h of stability for Li//Li batteries. Moreover, Li//LiFePO4 (LFP) full cells with this artificial protective layer perform well at 5 C, showcasing the potential of this film in lithium metal batteries.

Dual metal centers within a water-stable Co/Ni bimetallic metal-triazolate framework contribute to durable photocatalysis for water treatment.

Bimetallic metal-organic frameworks (MOFs) have been studied extensively in various fields, including photocatalytic and electrocatalytic applications. The enhanced catalytic activity is typically attributed to the synergistic effect of the two metals, often without further explanation. Here, we demonstrate a CoNi-bimetallic triazolate MOF with fixed metal occupancy within the MOF's secondary building unit. Due to the difference in electronegativity and so on, the charge redistribution between the two metal centers could be responsible for the enhanced photocatalytic activity. In addition, the metal(II)-triazolate MOFs we synthesized exhibit unique metal-N coordination and a strong bond between the metal center and triazole ring. Therefore, their crystal structure and high porosity are highly retained even after exposure to humid environments for several months or stirring in water for several days. Overall, the CoNi-bimetallic triazolate MOF combines the excellent water stability and high surface area of its two monometallic counterparts. It can be further tailored to yield the highest colloidal stability during photocatalytic water treatment. As a result, the dual metal centers within the bimetallic MOF, combined with boosted colloidal stability, demonstrate the highest reactive oxygen species generation and promising antibacterial performance compared to their Ni- or Co-based counterparts. These findings shed light on the future design of robust MOF-based photocatalysts, particularly bimetallic ones.

Surface-modified composites of metal–organic framework and wood-derived carbon for high-performance supercapacitors

The renewable nature, high carbon content, and unique hierarchical structure of wood-derived carbon make it an optimal self-supporting electrode for energy storage. However, the limitations in specific surface area and electrical conductivity defects pose challenges to achieving satisfactory charge storage in wood-derived carbon electrodes. Therefore, exploring diverse and effective surface strategies is crucial for enhancing the electrochemical energy storage performance. Herein, a decoration technique for enhancing aesthetic appeal involves applying a metal–organic framework (Ni/Co-MOF) containing nickel and cobalt onto the inner walls of wood tracheids. The sequential modification steps include carbonization, oxidation activation, and acid-etching. The Ni/NiO/CoO-CW-4 electrode, made by acid-etching carbonized wood (CW) doped with nickel, nickel oxide, and cobalt oxide for 4 h, has excellent surface area and pore size distribution, high graphitization degree, and exceptional conductivity. Furthermore, surface modification optimizes the surface chemistry and phase composition, resulting in a 0.8 mm thick Ni/NiO/CoO-CW-4 electrode with an exceptionally high areal capacitance of 16.76 F cm−2 at 5 mA cm−2. Meanwhile, the fabricated solid-state supercapacitor achieves an impressive energy density of 0.67 mWh cm−2 (8.38 mWh cm−3) at 2.5 mW cm−2 (31.25 mW cm−3), surpassing representative modified wood-based carbon electrodes by approximately 2–7 times. Additionally, the supercapacitor demonstrates exceptional stability, maintaining 96.21 % of capacitance even over 10,000 cycles. The parameters presented here demonstrate a significant improvement compared to those typically observed in most modified wood-derived carbon-based supercapacitors, effectively addressing common issues of low energy density and suboptimal cycling performance with wood carbon composites.

Characterization of Adsorbents Based on Pahae Natural Zeolite and Candlenut Shell Activated Carbon for Peat Water Purification

Abstract The importance of developing effective adsorbents for environmental applications cannot be overstated, particularly in the context of water and wastewater treatment. Previous research has extensively explored various natural and synthetic materials for their adsorption capabilities. Pahae natural zeolite, a naturally occurring aluminosilicate mineral, is known for its excellent ion-exchange properties and high surface area, making it a promising candidate for pollutant removal. Similarly, activated carbon derived from agricultural by-products, such as candlenut shells, has been recognized for its superior adsorption characteristics due to its porous structure and large surface area. This study focuses on the synthesis and characterization of an innovative adsorbent combining Pahae natural zeolite and candlenut shell activated carbon. The goal is to harness the synergistic effects of both materials to enhance the adsorbent’s performance. By investigating various compositions of these two materials, the research aims to optimize the adsorbent’s physical properties, particularly porosity and water absorption capacity. The findings reveal that a composition of 75% Pahae natural zeolite and 25% candlenut shell activated carbon yields optimal results, with a porosity of 57.26% and a water absorption capacity of 56.70%. These results underscore the potential of this composite adsorbent in improving water treatment processes and contribute to the growing body of knowledge on sustainable and efficient adsorbent materials.

Two-dimensional MXene Nanosheets and their Composites for Antibacterial Textiles: Current Trends and Future Prospects

Abstract: As a novel two-dimensional (2D) nanosheet (NS), MXene has attracted attention in antibacterial applications due to its excellent high surface area, remarkable hydrophilicity, strong flexibility, and excellent antibacterial properties. This review intends to provide valuable insight into the further development of antibacterial MXenes and their composite materials. In this paper, we review the antibacterial mechanisms of MXenes and their composite materials and summarize the research progress of antibacterial finishing fabrics, fibers and dressings based on MXene NSs. Due to the rich oxygen-containing groups, 2D MXene NSs and its composites exhibited significant antibacterial activity against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis so they have been widely used in antibacterial textiles including finishing fabrics, fibers, and dressings. 2D MXene NSs have showed some antibacterial properties based on cell experiments or blood tests. The antibacterial mechanisms mainly include physical sterilization and chemical oxidative stress sterilization. The future direction of antibacterial textiles based on MXenes was proposed.

Hydrophobic ZIF-8 nanoparticles loaded on chitosan for improved methanol adsorption from fermented wine.

Metal-organic frameworks (MOFs) have great potential for the adsorption of minor molecular alcohols in the vapor phase. However, the drawbacks of powdered MOFs, including low recyclability and problematic separation, limit their application in fermented wine. Chitosan (CS) is a low-cost, eco-friendly, moldable matrix used in the food industry. In this study, a novel CS@ZIF-8 adsorbent with excellent microporous surface area was successfully synthesized by incorporating hydrophobic ZIF-8 into CS. The results showed that CS@ZIF-8 beads had a high adsorption affinity for methanol at a Zn2+/2-methylimidazole molar ratio of 1:5. The adsorption mechanism of methanol on CS@ZIF-8 beads was systematically studied by X-ray photoelectron spectroscopy, isotherms, and kinetics. The Langmuir model calculated the maximum adsorption of methanol to 56.8mg/g. Adsorption kinetics are consistent with pseudo-second-order models. Furthermore, CS@ZIF-8 beads presented excellent recyclability for removing methanol for five consecutive cycles. It could treat 60 bed volumes of Chinese yellow wine in column filtration experiments to make the concentration below 50mg/L. In summary, the highly efficient CS@ZIF-8 adsorbent has great potential for methanol adsorption from fermented wines. PRACTICAL APPLICATION: Methanol will exhibit adverse symptoms such as weakness and headaches after it is ingested. Therefore, methanol control is an important safety factor in the production of fermented wine. The adsorption method is recognized as a widely used technique due to its high efficiency and selectivity. The CS@ZIF-8 adsorbent synthesized in this paper provides a new idea for methanol removal.

The N,N,N′,N′-tetraphenylbenzidine-based conjugated hypercrosslinked polymers for adsorping iodine and fluorescence sensing 2,4-dinitrophenol, iodine

Although progress has been made in the development of hypercrosslinked polymers (HCPs) for iodine uptake, their fluorescence performance and fluorescence sensing performance are rare due to the lack of conjugated behavior in common HCPs. Herein, the N,N,N′,N′-tetraphenylbenzidine-based conjugated hyper-crosslinked polymers (conjugated TPB-based HCPs) were efficiently fabricated via a one-step Friedel-Crafts arylation reaction by selecting N,N,N′,N′-tetraphenylbenzidine (TPB) and N,N′-diphenyl-N,N′-di(m-tolyl)benzidine (DPDB) as the basic building blocks and p-dimethoxybenzene (DMB) as an external crosslinker which will lead to the formation of the conjugated structures. The derived TPB-based HCPs (denoted as, TPB-DMB and DPDB-DMB) possessed excellent stability and high surface areas, Their iodine adsorption capacities are up to 4.25 and 3.56 g·g−1. The high iodine adsorption is caused by chemical adsorption. The fully conjugated structure and the 3D aryl network give the conjugated TPB-based HCPs excellent luminescence properties and fluorescence sensing properties for 2,4-dinitrophenol and iodine. The fluorescence sensing mechanisms of the conjugated TPB-based HCPs for DNP and I2 includes photo-induced electron process and the resonance energy transfer process. This study provides a viable approach for the development of highly efficient iodine sorbents and fluorescence sensors of DNP and iodine for addressing environmental issues.

Chemically Stable NiMoO4/NRGO Asymmetric Capacitor

AbstractIn this work, a chemically stable NiMoO4/NRGO nanocomposite was prepared via a facile hydrothermal method. The flower‐like structure of NiMoO4 (NMO) nanoparticles is randomly distributed on the surface of nitrogen‐doped reduced graphene oxide (NRGO) sheets, as observed in FESEM images. Compared to related reports, the NMO/NRGO (II) nanocomposite exhibits an excellent high surface area of 368.9 m2 g−1 and a mesoporous nature, as shown in N₂ adsorption‐desorption isotherms. The specific capacitance of the NMO/NRGO (II) electrode is 721 F g−1 at 1 A g−1 using a 6 M KOH electrolyte, retaining 91.2 % of its initial value after 5000 cycles. Electrochemical impedance spectroscopy (EIS) reveals that the electrode has a lower charge‐transfer resistance, indicative of good electrochemical behavior. An asymmetric device consisting of NMO/NRGO (II) || activated carbon (AC) electrodes exhibits a high energy density of 49.1 Wh kg−1 at 524.4 W kg−1 within a voltage range of 1.4 V, retaining 89 % of its initial capacitance after 5000 cycles, demonstrating good cyclic durability. These results suggest that the NMO/NRGO (II) electrode is a promising active material for supercapacitor devices.

Crab shell-based hierarchical micro/meso-porous carbon as an efficient nano-adsorbent for CO2/CH4 separation: experiments and DFT modeling

In this study, we prepared a range of nanoporous carbon nano-adsorbents from crab shells (CSs) using KOH activation and evaluated their suitability for selective adsorption of CO2/CH4 gas mixtures. We employed various characterization techniques, including XRD, FT-IR, SEM, Raman, TGA, and BET analysis, to assess the properties of these nano-adsorbents. Our investigation includes the systematic study of various parameters, such as activation time, activation temperature, and the KOH to CS activating agent ratio. The nanoporous carbons were evaluated for their CO2 adsorption capabilities at 1–10 bar and 25 ℃ condition. The results demonstrated that the CS-2-2-900 sample, activated for 1 h at 900 ℃ with a 2:1 ratio of KOH to CS, exhibited the highest gas adsorption capacity, reaching 7.217 mmol/g at a pressure of 10 bar under room temperature conditions. Additionally, the synthesized CS-2-2-900 sample displayed excellent surface area (914.85 m2/g), a pore volume of 1.1 cm3/g, and an average pore diameter of 4.82 nm. Furthermore, we functionalized the CSs to enhance their selectivity for ammonia adsorption. Using the Myers and Pravnitz theory, we calculated that the FCS-2-2-900 sample exhibited the highest selectivity, reaching 18.99 at 25 ℃ under pressures of up to 10 bar. To gain a more comprehensive understanding of the interactions between the adsorbents and the adsorbed molecules, as well as to identify the active sites involved in the adsorption process, we employed density functional theory (DFT). Our DFT calculations revealed that pyrrolic nitrogen and carboxylic sites played a significant role in enhancing the separation of CO2 in binary mixtures. In summary, nanoporous carbons derived from crab shells outperformed those derived from other waste materials. These functionalized porous nanocarbons represent promising adsorbents for the selective adsorption of CO2 gas in CO2/CH4 mixtures due to their nitrogen content, high porosity, stability, and economic efficiency.

Construction of intelligent response gene vector based on MOF/Fe3O4/AuNRs for tumor-targeted gene delivery

Metal-organic frameworks (MOFs) have the potential to efficiently carry cargo due to their excellent porosity and high surface area. Nevertheless, conventional MOFs and their derivatives exhibit low efficiency in transporting nucleic acids and other small molecules, as well as having poor colloidal stability. In this study, a ZIF-90 loaded with iron oxide nanoparticles and Au nanorods was prepared, and then surface-functionalized with polyethyleneimine (PEI) to create a multifunctional nanocomposite (AFZP25k) with pH, photothermal, and magnetic responsiveness. AFZP25k can condense plasmid DNA to form AFZP25k/DNA complexes, with a maximum binding efficiency of 92.85 %. DNA release assay showed significant light and pH responsiveness, with over 80 % cumulative release after 6 h of incubation. When an external magnetic field is applied, the cellular uptake efficiency in HeLa cells reached 81.51 %, with low cytotoxicity and specific distribution. In vitro transfection experiments demonstrated a gene transfection efficiency of 44.77 % in HeLa cells. Following near-infrared irradiation, the uptake efficiency and transfection efficiency of AFZP25k in HeLa cells increased by 21.3 % and 13.59 % respectively. The findings indicate the potential of AFZP25k as an efficient and targeted gene delivery vector in cancer gene therapy.

Enhanced removal of sulfamethoxazole via adsorption and photodegradation using biochar-modified iodine-doped TiO2 photocatalysts under simulated sunlight

This study aimed to prepare a biochar-modified iodine-doped titanium dioxide composite photocatalyst (B/I-TiO2) via hydrothermal reaction and evaluate its performance in sulfamethoxazole (SMX) degradation under simulated sunlight. Biochar was prepared from four agricultural wastes using hydrothermal and pyrolysis technologies, resulting in 3–30 graphite layers with a d-spacing of 0.35 nm. Hydrothermal activation transformed the disordered structure into a graphite microcrystalline structure, producing biochar with a quasi-three-dimensional graphene structure. Doping with 1–15 wt% of this biochar shifted the characteristic wavelength of B/I-TiO2 to 423–426 nm and increased the specific surface area by 1.25–1.94 times. The 5LB700H2I1T composite photocatalyst found the highest SMX removal efficiency of 40 %, and the 5WB900H2I1T composite photocatalyst found the highest SMX photodegradation efficiency of 30 %, respectively, irradiated with simulated sunlight of 3 hours. The wavelength redshift and degradation performance enhancement primarily resulted from iodine doping and the biochar's excellent crystallinity and high surface area. SMX removal was achieved through adsorption and photodegradation, with hydroxyl radicals and electron holes playing a significant role compared to superoxide radicals.

An innovative triple interface reinforced photocatalytic system based on BiOCl/BaTiO3@Co-BDC-MOF composite for the simultaneous detoxification of Cr(VI) and sulfamethoxazole

The development of effective photocatalysts for the reduction of Cr(VI) and the degradation of antibiotics remains a challenge. The present work reports the development of a novel heterojunction composite material, BiOCl/BaTiO3@Co-BDC-MOF (BOC/BTO@Co-MOF), based on solvothermal techniques. To characterize the surface and bulk features of the material, techniques such as FE-SEM, HR-TEM, BET/BJH, XPS, FT-IR, p-XRD, and UV–Vis-DRS were used. Based on the results, the BiOCl/BaTiO3 nanocomposites are uniformly dispersed on the rod-shaped Co-BDC MOF, resulting in a layered texture on the surface. A further advantage of the composite structure is the strong interfacial enhancement facilitating the separation of photoexcited electron-hole pairs. Also, compared to its pristine counterparts, the heterostructure material exhibited excellent surface area and pore properties. The photocatalytic efficiency towards reduction and degradation of Cr(VI)/SMX pollutants were evaluated by optimizing various analytical parameters, such as pH, catalytic loading concentrations, analyte concentration, and scavenger role. The specially designed BOC/BTO@Co-MOF composite achieved a 96.5% Cr(VI) reduction and 98.2% SMX degradation under 60.0–90.0 min of visible light illumination at pH 3.0. This material is highly reusable and has a six-time recycling potential. The findings of this study contribute to a better understanding of the efficient decontamination of inorganic and organic pollutants in water purification systems.

One Pot Facile Bio-Synthesis of Anti-angiogenic Iron Oxide Nanoparticles Using the Bio-Reductant Sida spinosa

Abstract Owing to the superior characteristics of the iron oxide nanoparticles Fe2O3 (SS-Fe) attracted a lot of attentions in various applications due to their unique physical and chemical properties. Moreover, due to their excellent surface area, compatible nano size spherical shape and ecofriendly synthesis route make them preferable and prudent in industrial and pharmacological applications. Based on this view, it aims to the bio-fabrication of iron oxide nanoparticles Fe2O3 (SS-Fe) by Sida spinosa extract as bio-reductant and stabilizing agent. The reports reveal that the nanoparticles have effective pharmacological applications. Highly economical and environmentally benign methodology supports the derivation of Fe2O3 (SS-Fe) nanoparticles in high yield. The SEM images reveals that, Fe2O3 (SS-Fe) nanoparticles possess spherical shape and the size of 81.72nm. The corresponding Fe-O band observed at 560.93 cm−1 indicates the formation of the nanoparticles. The EDX signals further confirms the nanoparticles by the peaks obtained for iron and oxygen atoms only. The absorbance peak at 374.00nm in UV-Visible spectrum evidently proves the synthesis of iron oxide nanoparticles. The λex = 645.18nm of the emission spectrum further supports the confirmation. The fabricated iron oxide nanoparticles show moderate antibacterial and a good antifungal efficacy. The iron oxide nanoparticles effectively inhibit the protein supply to the cancer cells which were injected to the egg yolk at 50µg/ml concentration gives 60.86% of inhibition.

CuFe2O4 Nanofiber Incorporated with a Three-Dimensional Graphene Sheet Composite Electrode for Supercapacitor and Electrochemical Sensor Application

The demand for regenerative energy and electric automotive applications has grown in recent decades. Supercapacitors have multiple applications in consumer alternative electronic products due to their excellent energy density, rapid charge/discharge time, and safety. CuFe2O4-incorporated three-dimensional graphene sheet (3DGS) nanocomposites were studied by different characterization studies such as X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The electrochemical studies were based on cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements. As prepared, 3DGS/CuFe2O4 nanocomposites exhibited an excellent surface area, high energy storage with appreciable durability, and excellent electrocatalysis properties. A supercapacitor with 3DGS/CuFe2O4-coated nickel foam (NF) electrodes exhibited an excellent specific capacitance of 488.98 Fg−1, a higher current density, as well as a higher power density. After charge–discharge cycles in a 2.0 M KOH aqueous electrolyte solution, the 3DGS/CuFe2O4/NF electrodes exhibited an outstanding cyclic stability of roughly 95% at 10 Ag−1, indicating that the prepared nanocomposites could have the potential for energy storage applications. Moreover, the 3DGS/CuFe2O4 electrode exhibited an excellent electrochemical detection of chloramphenicol with a detection limit of 0.5 µM, linear range of 5–400 µM, and electrode sensitivity of 3.7478 µA µM−1 cm−2.

FDU-12@AGA-Pd: A green, novel, recyclable, and highly versatile mesoporous catalyst for C[sbnd]C coupling reaction and synthesis of tetrazoles

Herein, we present an efficient, novel nanocatalyst through the immobilization of AGA-Pd onto the inside of mesoporous silica FDU-12 channels that were successfully synthesized by a simple procedure. The catalytic activity of FDU-12@AGA-Pd was investigated for the synthesis of 1H-tetrazole derivatives and the Suzuki reaction. The synthesized compounds were identified and confirmed with the help of 1H-NMR. In this research, the nanocatalyst was prepared by the immobilization of palladium into FDU-12 channels coated with 2-amino-5-guanidinovaleric acid (AGA). N2 adsorption-desorption isotherms indicated excellent BET surface area for FDU-12 and FDU-12@AGA-Pd, which is 627.27 and 106.69 (m2 /g), respectively. The physical and chemical properties of raw and modified samples (FDU-12, FDU-12@AGA-Pd) were characterized by Thermogravimetric analysis (TGA), N2 adsorption-desorption analysis, Inductively coupled plasma optical emission spectroscopy (ICP-OES), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transforms infrared spectroscopy (FT-IR), Mapping, and X-ray diffraction (XRD). The synthesized mesoporous nanocatalyst was recovered and reused in five continuous cycles without considerable change in its catalytic activity.SynopsisOur findings will help researchers and industrial factories to apply a green and sustainable mesoporous catalyst to produce a variety of valuable organic compounds and pharmaceutical products.

The Challenge of E-Spinning Sub-Millimeter Tubular Scaffolds-A Design-of-Experiments Study for Fiber Yield Improvement.

In tissue engineering, electrospinning has gained significant interest due to its highly porous structure with an excellent surface area to volume ratio and fiber diameters that can mimic the structure of the extracellular matrix. Bioactive substances such as growth factors and drugs are easily integrated. In many applications, there is an important need for small tubular structures (I.D. < 1 mm). However, fabricating sub-millimeter structures is challenging as it reduces the collector area and increases the disturbing factors, leading to significant fiber loss. This study aims to establish a reliable and reproducible electrospinning process for sub-millimeter tubular structures with minimized material loss. Influencing factors were analyzed, and disturbance factors were removed before optimizing control variables through the design-of-experiments method. Structural and morphological characterization was performed, including the yield, thickness, and fiber arrangement of the scaffold. We evaluated the electrospinning process to enhance the manufacturing efficiency and reduce material loss. The results indicated that adjusting the voltage settings and polarity significantly increased the fiber yield from 8% to 94%. Variations in the process parameters also affected the scaffold thickness and homogeneity. The results demonstrate the complex relationship between the process parameters and provide valuable insights for optimizing electrospinning, particularly for the cost-effective and reproducible production of small tubular diameters.

Sustainable graphene production for solution-processed microsupercapacitors and multipurpose flexible electronics

The growing demand for portable and wearable electronics, Internet of Things microdevices, and wireless sensor networks has led to the development of miniaturized energy storage devices, such as microsupercapacitors (mSCs). With excellent electrical conductivity and high surface area in a layered structure, graphene materials are ideal for mSCs, but current manufacturing methods still hinder their widespread integration. Here, we propose a sustainable approach for the rapid and eco-friendly production of few-layer graphene flakes based on the exfoliation of graphite in water by a combination of high-shear mixing and a high-pressure airless spray. An all-carbon composite paste with high electrical conductivity and tunable viscosity was designed to fabricate planar, interdigitated mSCs on polyethylene terephthalate (PET). The flexible, metal-free mSCs achieved a Coulombic efficiency close to 100%, with areal and volumetric capacitances of 6.16 mF cm−2 and 2.46 F cm−3, respectively. The maximum energy density exceeds 200 μWh cm−3 with 91.5% capacitance retention after 10000 galvanostatic chargedischarge cycles. The mSCs retain the same performance when subjected to a wide bending range and can be easily modularized to adjust the voltage and capacitance outputs. Finally, high-performance coatings for electromagnetic interference shielding and wearable strain sensors are also fabricated to demonstrate the multipurpose applicability of the graphene-based paste.

Molecular receptors integrated bimodal porous polymer scaffolds as portable solid-state optical ion-sensors and extractors for the selective capturing of ultra-trace toxic copper ions

BackgroundEnvironmental contamination by heavy metal ions has caused growing ecological and public health concerns. In this line, monitoring of copper toxicity gains importance due to its application in industrial, agricultural, domestic, medical and technological sectors. Although noteworthy breakthroughs were made, critical issues, such as portability, the need for well-trained personnel, costly/complex instrumentations, long response time, and the introduction of secondary contaminants, required attention. Hence, developing a low-cost, user-friendly, real-time, portable analytical platform for rapid and on-site analysis remained imperative. Solid-state colorimetric sensors have gained widespread popularity due to their low cost, ease of use, and brilliant sensitivity/selectivity. ResultsWe have successfully unfolded an ultra-portable azomethine-infused structurally interwoven polymer monolith as the solid-state chromatic sensor for the quantitative naked-eye detection of ultra-trace Cu2+ in industrial/environmental samples. For the sensor fabrication, non-hygroscopic conjugated Schiff-base receptors, namely N-(1E,2E)-3-(4-dimethylamino)phenyl)allylidene)-3-nitrobenzohydrazide (DPAN) and 2,3-bis(((1E,2E)-3-(4-dimethylamino)phenyl)allylidene)amino)malononitrile (DPAM) were synthesized in-house and voluminously immobilized onto a crack-free porous poly(4VP-co-EGDMA) monolith framework. The topological structure and functionalities of the porous polymer monolith and chromatic sensor materials were examined using various surface analytical and microscopic techniques. The excellent surface area and intriguing interlaced porosity features of the tailor-made polymer monolith facilitated the voluminous anchoring of the chromatic receptors for the selective/sensitive targeting of Cu2+. The DPAN and DPAM receptor-loaded poly(4VP-co-EGDMA) sensors exhibited a linear range of 0–150 μg/L, with the limit of detection of 0.11 and 0.13 μg/L for Cu2+, respectively. The sensors manifested Cu2+ specificity amidst concomitant matrix ions to highlight the relevance of the proposed solid-state sensor. SignificanceThe sensor materials offered a reliable approach for detecting and quantifying environmentally toxic and industrially pertinent Cu2+ from aqueous samples, with the prospect of large-scale production, owing to the sensor's integrated compact design that can be reused for repeated real-time surveillance. The sensor's ability to sense/trap traces of toxic Cu2+ can provide an early warning about the growing toxicity in a particular resource, thereby providing an opportunity to initiate remediation protocols for speedy decontamination.

Physicochemical Characterization of Zeolite Materials Produced from Selected Low-Cost Agricultural Wastes

Zeolites play a crucial role in adsorption processes for eliminating pollutants from industrial effluents and are extensively utilized in catalytic activities across diverse syntheses. This study focused on the conversion of three agricultural wastes—corncob, groundnut shell, and sugarcane bagasse—into zeolitic materials through three analytical methods: hydrothermal, microwave sintering, and alkali fusion, respectively. Standard methods were employed to assess the physicochemical parameters of the resulting zeolites. Generally, the produced zeolites had excellent surface areas and porosities. However, zeolites synthesized from sugarcane bagasse via the alkali fusion method exhibited highest porosity (80.9%), whereas that derived from corncob demonstrated highest surface area (1335 m2/g). Point of zero charge for the produced zeolites was within the range of 7.9-9.8, with zeolite produced from groundnut shells via alkali fusion having the highest value (9.8). The elevated porosities and surface areas, and point of zero charge of the synthesized zeolites signify their enhanced adsorptive capacity, implying their suitability for application as adsorbents for the removal of organic and inorganic pollutants. These findings underscore the effectiveness of synthesized zeolites in reducing or completely removing pollutants such as phenols, dyes, pesticides, heavy metals, and inorganic anions from wastewater.