Large Porous Structure Research Articles

Preparation, properties and applications of porous hydrogels containing thiol groups for heavy metal removal

A novel porous hydrogel adsorption material, called PAM/PAA/PDMTM gel, has been developed for the removal of heavy metal ions in complex systems. The gel is composed of polyacrylamide, polyacrylic acid, and poly(2,4-dimercapto-6-mercaptopropenyl-1,3,5-triazine) monomer. This hydrogel material features a large pore structure, abundant active functional groups, high swelling properties, good thermal stability, and remarkable regeneration ability. More importantly, the hydrogels contain a variety of active groups, they show good complex adsorption properties for heavy metals. The PAM/PAA/PDMTM gel demonstrated excellent adsorption performance, with the maximum adsorption capacity of Cu2+, Cd2+ and Pb2+ reaching 92.33, 110.08 and 200.97 mg g−1 (pH 5, 298 K), respectively. And the adsorption was in accord with the pseudo-second-order model and Langmuir model. Notably, the PAM/PAA/PDMTM gel also demonstrated remarkable adsorption capacity for Pb even in soil, making it an efficient adsorption material for removing heavy metals from both water and soil samples.

Nanocomplexes with anchored [formula omitted]-tetraethylene pentamine electrochemiluminescence system: Self-enhanced coupled photothermal strategy detection of thyroglobulin

A synergistic amplified electrochemiluminescent (ECL) immunoassay was constructed byutilizing an efficiently self-enhanced signal tag and sensing substrate with satisfactory photothermal property for thyroglobulin ultrasensitive detection. Concretely, tetraethylene pentamine (TEPA) was first attempted for the coreactant of Rubpy32+, and mesoporous silica nanostars with large surface area and porous structure was designed as a support material to integrate Rubpy32+ and TEPA, forming a self-enhanced signal tag to improve ECL efficiency. Additionally, magnetic beads with excellent photothermal effect was used as ideal sensing substrate to obtain the further amplified ECL signal because of the accelerated electron diffusion and reaction process induced by increased electrode temperature under the near-infrared laser irradiation. With the self-enhanced and photothermal synergistic amplified strategy, the proposed ECL sensor showed a wide linear range from 10−5 to 10 ng/mLwith a low detection limit of 3.3 × 10−6 ng/mL. This work will provide a promising avenue to simplify the synthesis of self-enhanced ECL emitter complexes, and pave the avenue for achieving synergistic enhancement of ECL signals by incorporating probe substrates.

Simple synthesis of hydrangea-like CuO structure constructed by porous nanosheets for rapid detection of NO2 at low temperature

It is of great significance to develop gas sensors with fast and high response under low energy consumption for practical monitoring of harmful gases in industrial production and environment. In this work, hydrangea-like CuO material constructed by porous nanosheets with a specific surface area of 42.45 m2 · g−1 was synthesized by a simple one-step solution method without the addition of surfactant. It has good sensing performance to 10 ppm NO2 (S = 133.6) and short response time (4 s) at near room temperature (50 ℃), which is significantly superior to most CuO based NO2 gas sensors reported so far. The good gas sensing properties may be attributed to the synergistic effect of large specific surface area and two-dimensional porous structure. Therefore, hydrangea-like CuO may become a popular sensitive material capable of rapid detection of NO2, and the synthesis method of this material can also meet large-scale production.

Template-free route to fabricate extra-lightweight ceramsite with a single large pore structure

As a lightweight aggregate, single-pore ceramsite is used in the construction industry, which can effectively solve the problems of traditional porous ceramsite with high bulk density, poor thermal insulation performance and easy leakage. However, preparing single-pore ceramsite by template method brings high cost, complicated process, and serious pollution problems. To overcome these challenges, in this work, we used copper tailings (60 wt%) and clay (40 wt%) as raw materials to prepare extra-lightweight single-pore ceramsite by template-free method. By adding 0.7 wt% SiC to the raw material and sintering at 1180 °C for 15 min, the extra-lightweight single pore structure with 200 density class in GB/T 17431.1–2010 can be obtained. Based on the thermodynamics and the sintered morphology, the mechanism of the single-pore structure formed by the pores sealed by the liquid phase is summarized. Template-free method is beneficial to save the preparation cost, simplify the process flow and reduce carbon emissions. As a result, template-free method provides a new, green, economical, and simple way for single-pore ceramsite production.

Phase change materials embedded in expanded clay aggregates to develop energy storage concrete: A review

Thermal energy storage (TES) based on phase change materials (PCM) is an effective strategy to reduce energy consumption in buildings. The efficient implementation of TES in building through PCMs, requires modification of their thermal performance, appropriate design and evaluation of their thermal and economic efficiency. One major challenge in the application of PCMs is the selection of high-performance and environmental-friendly supporting materials to overcome the most critical drawback of PCMs (solid-to-liquid transition and resulting leakage). This review focuses on expanded clay (EC) lightweight aggregate (LWA), as one of the promising supporting materials for development of form-stabilized PCM (FSPCM) in the lightweight concrete (LWC) industry. The large specific surface area and porous structure of expanded clay can maintain considerable amount of PCM. In addition, mechanical properties and compatibility with various PCMs make EC a suitable carrier. A detailed review of available researches is presented to elucidate the properties of PCMs embedded in EC for thermally efficient cement-based concrete. Various combinations of EC with the most used PCMs, thermal and mechanical properties of matrices containing PCM-EC, strategies to improve the efficiency of PCM performance, and finally the impact of PCM-EC based concretes on the thermal comfort of buildings are critically summarized.

Ultrasensitive detection and efficient removal of mercury ions based on covalent organic framework spheres with double active sites

In present work, a new spherical covalent organic framework (TFPB−APTU COF) with good photoelectric property and double active sites (secondary amine (−NH−) group and sulfur (S) atom) was prepared for ultrasensitive detection and efficient removal of mercury ions (Hg2+). The –NH− group and S atom can capture free Hg2+ by coordination and chelation interaction, and the related steric hindrance effect reduces the photocurrent signal of the TFPB−APTU COF, resulting in the highly sensitive photoelectrochemical analysis of Hg2+ with a wide linear response range (0.01−100000 nM) and low detection limit (0.006 nM). On the other hand, the developed TFPB−APTU COF has large removal capacity (2692 mg g−1), good regeneration capability, and high removal speed for Hg2+ removal based on the double active sites (−NH− group and S atom), large specific surface area and porous spherical structure. The developed TFPB−APTU COF spheres show great potential in monitoring and treatment of environmental pollution of Hg2+.

In situ irradiated XPS proved efficient charge transfer on graphdiyne (CnH2n-2) based tandem NiFe PBA/CuI/GD S-scheme heterostructure for photocatalytic hydrogen production

Due to its abundant carbon chemical bonds, large conjugated system and natural pore structure, graphdiyne (GD, CnH2n-2) shows great advantages in growth, assembly and performance regulation, and is a key material to promote innovative development in catalysis, energy and other fields. In this study, NiFe PBA cube was prepared by coprecipitate method, and then NiFe PBA/CuI/GD ternary composite photocatalyst was formed by tightly coating NiFe PBA and CuI with graphitylene material. In situ irradiated X-ray photoelectron spectroscopy characterizes the change in electron cloud density of a catalyst under illumination, so as to determine the series-type transfer path of photogenerated electrons between three single photocatalysts, thus revealing the formation of double S-scheme heterojunction. Photocurrent and fluorescence tests have confirmed that the photogenerated carriers in NiFe PBA/CuI/GD can be transferred rapidly and utilized efficiently to participate in the photocatalytic reaction under the action of strong interfacial electric field. In addition, the three-dimensional structure of NiFe PBA and CuI and the surface carbon layer synergistic effect to expand the utilization rate of visible light catalyst. This work provides a new idea for the construction of S-scheme heterojunction and the application of new carbon materials in the field of photocatalysis.

2D/3D porphyrin-based porous polyaniline derivatives for highly efficient adsorption of Au3+ ions

Developing multi-functional porous organic polymers (POPs) to solve metal ions environmental pollution still faces challenges. In this work, two-dimensional (2D) and three-dimensional (3D) porphyrin-based porous polyaniline derivatives were obtained by chemical oxidation polymerization. Benefiting from their large pore structure, good hydrophilic properties and excellent coordination ability, they showed excellent adsorption properties. The adsorption results show that they have high adsorption selectivity and efficiency for Au3+ ions. The maximum adsorption efficiency of Au3+ ions was 99.7%, and the maximum adsorption capacity was 1152 mg g−1. The adsorption mechanism was investigated and discussed, providing theoretical support for the design of novel porphyrin-based POPs for Au3+ ions adsorption. This work opens up a new path for the development of novel porphyrin-based POPs.

ZnO-based Cu metal-organic framework (MOF) nanocomposite for boosting and tuning the photocatalytic degradation performance.

Although metal-organic frameworks (MOFs) are a viable choice for photocatalysts with large surface area and tunable pore structure, the rapid recombination of excited photogenerated charges results in low activity towards photodegradation. Aiming at improving the photocatalytic activities of MOFs, different strategies to incorporate MOF with light-harvesting semiconductors have been developed. In this research, we report an effective photocatalyst designed by incorporating Cu-MOF with ZnO for the photocatalytic degradation of Rose Bengal exhibiting excellent degradation efficiency of 97.4% in 45min under natural sunlight with catalyst dosage of 320mg/L. The optical, morphology and surface characteristics of the prepared nanocomposite were studied using scanning electron microscopy (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET) analysis, thermogravimetric (TGA) analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and ultraviolet diffused reflectance spectroscopy (UV-DRS) techniques. Further studies showed that the degradation followed first-order kinetics with a rate constant of 0.077869min-1. The degradation mechanism was investigated by photoluminescence (PL) study, XPS, zeta potential and quenching experiment in presence of different scavengers. Meanwhile, the fabricated composite displayed good recovery and reuse properties up to 5 cycles as revealed by XRD analysis proving itself a potential MOF-based photocatalyst towards environmental remediation process.

Preparation of Fe3O4 Magnetic Material Modified by Fulvic Acid and Its Adsorption Performance for Methylene Blue

AbstractIn this paper, a kind of Fe3O4 magnetic nano material modified by fulvic acid (FA) was prepared and used for removing methylene blue in wastewater. The structure and morphology of the material were characterized by FT‐IR, PXRD, BET, XPS, VSM, SEM and TEM. The results showed that FA successfully coated on the surface of Fe3O4 magnetic nano particles. The newly prepared magnetic material had large specific surface area and porous structure. The specific surface area of the material was 92.15 m2/g. The average pore size of the material was 8.917 nm. Its saturation magnetization could reach to 55.74 emu/g. The magnetic responsiveness of the material was obvious. The magnetic material could be recovered by the magnet so it was easy to separate with the solution. The adsorption kinetic data fitted better with pseudo second order kinetic equation. The isothermal adsorption processes of the modified material to methylene blue had better linear correlation with Langmuir isothermal adsorption model. The thermodynamic parameter results indicated that the adsorption processes of the material to methylene blue were spontaneous exothermic processes. The results of the cyclic experiments indicated that the material had a certain value for reuse.

CeO2-Based Porous Carbonaceous Frameworks as Antioxidant Nanozymes for Scavenging Reactive Oxygen Species and Adsorbing Benzo[a]pyrene.

Barbecue smoke, car exhaust, cigarette smoke, and other waste gases contain toxic reactive oxygen species (ROS) and polycyclic aromatic hydrocarbons (PAHs). Herein, CeO2-based porous carbonaceous frameworks (CeO2 PCFs) were explored as antioxidant nanozymes to scavenge ROS and absorb benzo[a]pyrene (B[a]P). Using cerium-based frameworks as the precursors, CeO2 PCFs were constructed by high-temperature calcination. Due to excellent superoxide dismutase-like and catalase-like activity, CeO2 PCFs could effectively eliminate superoxide radical, hydroxyl radical, and hydrogen peroxide. The 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) free radical scavenging assay had substantiated free radical scavenging ability of CeO2 PCFs. In addition, with a large surface area and porous structure, CeO2 PCFs could adsorb B[a]P efficiently. The designed CeO2 PCFs may provide a new opportunity as scavengers of ROS and absorbents of PAHs in some harmful gases.

Biocarbon with large specific surface area and tunable pore structure from binary molten salt templating for supercapacitor applications

Tailoring the pore structure while maintaining a large specific surface area (SSA) of biocarbon remains a challenge, especially forsingle activating/templating system. Herein, a new binary ZnCl2-CaCl2 (Zn-Ca) molten salt system is explored for one-step carbonization of chitin to manufacture biocarbon with hierarchically tunable micro/mesoporous structure. By adjusting the salt to chitin ratio, biocarbon with large SSA (>1000 m2/g), controllable mesopore fractions (19.3%–67.9%) and high yield (up to 35%) has been fabricated. The optimal SSA, total pore and mesopore volume are obtained at 1671 m2/g, 1.32 cm3/g and 0.64 cm3/g, respectively, showing the synergistic effect of Zn-Ca on achieving well-balanced pore characteristics. Besides, the total nitrogen contents could also be enhanced. Such balanced physicochemical properties lead to excellent supercapacitor performance, achieving 301.2 F/g specific capacitance at a current density of 0.5 A/g as measured from a three-electrode system. The assembled supercapacitor cell also shows a notable rate capability of 70.2% at an ultrahigh current density of 50 A/g with a low internal resistance, which can reach a remarkable power density of 27 kW/kg. The outstanding capacitive performance is attributed to the modulated micro-mesoporous structure for efficient ion diffusion and adsorption, as well as appropriate heteroatoms for pseudo-capacitance contribution.

Enhanced electrochemical hydrogen storage properties of Ti49Zr26Ni25 quasicrystal alloy by doping with CO2-activated porous graphene

Ti49Zr26Ni25 quasicrystal alloy was fabricated via mechanical alloying and subsequent annealing. In order to enhance the electrocatalytic activity and conductivity of Ti49Zr26Ni25, the porous graphene (PoRGO) material was synthesized by a facile CO2 activation treatment of reduced graphene oxide (RGO). The composites of Ti49Zr26Ni25 doping with different amount of PoRGO were manufactured through ball milling. During the electrochemical hydrogen storage test, the porous Ti49Zr26Ni25 + PoRGO exhibited higher discharge capacity than Ti49Zr26Ni25 + CRGO and conventional Ti49Zr26Ni25 alloy. Moreover, the additive amount of PoRGO had great influence on the electrochemical properties of Ti49Zr26Ni25. Eventually, 5 wt% PoRGO modified Ti49Zr26Ni25 alloy electrode achieved a highest discharge capacity of 270 mAh/g. The large specific surface area and distinctive porous structure of porous graphene could offer more electrochemical active sites and facilitate the hydrogen diffusion. In the meantime, the cycling stability, high-rate dischargeability (HRD) and kinetic properties of Ti49Zr26Ni25 were also improved after PoRGO loading. Consequently, porous graphene can be potential used as the dopant for the modification of hydrogen storage alloys.

Modification of metal–organic frameworks Zn(BDC) with 8-hydroquinoline and their application in lymph node imaging in vivo

The large surface area and porous structure of MOF materials could provide binding sites for fluorescent moieties for bioimaging. Herein, we reported the preparation of fluorescent MOF material Zn(BDC) by 8-hydroquinoline modification [Zn(BDC)-8HQ]. Zn(BDC)-8HQ emitted strong fluorescence at 507 nm. The fluorescent Zn(BDC)-8HQ had a hydrodynamic radius of 255 nm, suitable for lymph node tracing. After subcutaneous injection, a bright spot could be distinguished at the injection site. The injections to front extremities resulted in sentinel lymph node accumulations. The low toxicity of Zn(BDC)-8HQ was evidenced by serum biochemical index and histopathological observations.

Optimization of dendritic TS-1/Silica micro–mesoporous composites for efficient hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene

A novel composite material (TD) composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres (DMSNs) was successfully prepared. The TD composite material had open pore structure and large specific surface area, which was conducive to the mass transfer of reactants and products. The Ti element in TS-1 could be used as an electron assistant, and the spillover d-electrons were conducive to the improvement of the sulfidation and dispersion of MoS2, thereby forming more type II MoS2 active phases. The incorporation of Ti could bring more Brønsted (B) and Lewis (L) acid, which was conducive to the hydrogenation pathway (HYD) selectivity (41.2%) of dibenzothiophene (DBT) hydrodesulfurization (HDS) and isomerization (ISO) route selectivity (21.9%) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS, thus improve the HDS activity of DBT and 4,6-DMDBT. NiMo/TD-70 (Aging temperature = 70 °C) had the best HDS activities of DBT (99.0%) and 4,6-DMDBT (93.7%) due to its large open pore structure, good acidity, suitable metal-support interaction (MSI) and perfect dispersion of the metallic active sites.

Biowaste-based Porous Carbon for Supercapacitors: Synthesis, Fabrication and Electrochemical Performances: A Review

Abstract: The development of low-cost, high-efficiency electrode materials for supercapacitors is motivated by the growing need for green and affordable clean energy (SDG goal 7). Developing new energy conversion and storage technologies, such as supercapacitors, batteries, and fuel cells, is a viable option for meeting energy demands while addressing environmental concerns. Recent advances in carbonaceous materials derived from biowaste for supercapacitor applications have piqued the interest of academics and industry alike. Because of their large surface area and porous structure, activated carbon-based electrode materials can be used in various applications, including supercapacitors, fuel cells, and batteries. Carbonaceous materials such as carbon nanotubes, graphene, and activated carbon, exhibit EDLC-like behavior mainly due to ion adsorption at the electrode interface. In recent years, several potential strategies for the synthesis and structural architecture of biowaste-derived porous carbons have been tested with varying degrees of success. Thus, it is critical to evaluate the prospects for biowaste-derived porous carbon materials used as supercapacitor electrodes. In this review, we highlight how different biowaste-derived porous carbon affects the surface properties of carbon nanostructures and how this affects their electrochemical performance. Additionally, the extent to which various biowastes have been utilized as porous carbon for supercapacitor electrodes is addressed. The different synthesis techniques, such as hydrothermal carbonization, physical activation, chemical activation, and microwave-assisted activation, are briefly described in this review. Finally, we highlight fabrication techniques as well as electrochemical performance measurements such as CV, GCD, EIS, energy density, and power density.

Synthesis and Characterization of Metal-Organic Framework as Battery Electrodes

Metal organic framework-derived carbons (MOFDCs) are materials with great potential and can be used as electrochemical energy storage because these have a large surface area and pore structure that can be adapted to needs. MOFs have porous crystals in which metal ions or clusters are linked by organic ligands. The purpose of this study was to determine the physical and electrochemical properties of MOF5 synthesized at different temperatures. The MOFs synthesis method which is classified as complicated can be simplified and the use of hazardous solvents can be reduced by means of partial substitution using water solvents. To prepare MOFs can be done in several ways, such as liquid phase epitaxy, supersonic cold spraying, direct gas phase preparation, and interface-assisted synthesis. MOFs have applications in optics, sensing, catalysis, adsorption, and modeling, as well as electrochemical energy storage. Potential application as an interesting electrode material to be studied through the synthesis method. In this study, MOF5 was synthesized at temperatures between 200°C-600°C. To prepare MOF5, zinc nitrate tetrahydrate and acetic acid were dissolved in DMF (N, N-dimethyl formamide). The remaining precipitate (MOF) was immersed three times in DMF and three times in chloroform for 24 hours for each immersion. In general, different MOF5 synthesis affects the microstructure, elemental content, optical properties (transmittance and absorbance), electrical properties, and electrochemical properties

A porous TiC supported nanostructured complex metal oxide ceramic electrode for oxygen evolution reaction

Developing low-cost and high-performance electrodes with a customized size is greatly demanded to satisfy the industrial requirement of electrochemical water splitting. To meet this challenge, a novel binder-free electrode consisted of perovskite Sr2Fe1.4Ni0.1Mo0.5O6-δ (SFNMO) nanofibers or spinel NiCo2O4 (NCO) nanosheets tightly bonded on a porous TiC substrate has been developed to catalyze the oxygen evolution reaction in alkaline water electrolysis. The optimal SFNMO/TiC electrode requires a stable overpotential of ∼380 mV to achieve a current density of 30 mA cm−2 within 20 h of operation. The competitive OER performance of such electrode can be attributed to its unique large finger-like straight pore structure, which favors the mass transfer of electrolyte solution as well as produced oxygen bubbles. Furthermore, the strong adhesion between metal oxide catalysts and TiC substrate is derived from the interfacial reaction (form a TiCxOy solid solution), thus lowering the contact resistance of catalyst/substrate interface and promoting the charge transfer kinetics of electrodes, which leads to an outstanding catalytic performance.

Flower-like WSe2 used as bio-matrix in ultrasensitive label-free electrochemical immunosensor for human immunoglobulin G determination.

The abnormal concentrations of human immunoglobulin G (hIgG) refers to many kinds of diseases. Analytical methods with the characteristics of rapid response, easy operation and high sensitivity should be designed to accurately determinate the hIgG levels in human serum. In this work, a label-free electrochemical immunosensor based on WSe2/rGO was developed to sensitively detect human immunoglobulin G. First, the flower-like transition metal dichalcogenides (TMDCs) Tungsten Diselenide (WSe2) with large effective specific surface area and porous structure was synthesized by hydrothermal synthesis. As a bio-matrix, the flower-like WSe2 efficiently increased the active sites for loading antibodies. Meanwhile, reduced graphene oxide (rGO) obtained by tannic acid reduction was used to improve the current response of the sensing interface. WSe2 was combined with rGO and the electrochemical active surface area (ECSA) of the sensing interface was enlarged to 2.1 times that of GCE. Finally, the combination of flower-like WSe2 and rGO broadened the detection range and reduced the detection limit of the sensing platform. The immunosensor exhibited a high sensitivity with a wide linear range of 0.01-1000ng/mL and low detection limit of 4.72pg/mL. The real sample analysis of hIgG were conducted under optimal conditions, and the spiked recovery rates were between 95.5 and 104.1%. Moreover, satisfactory results were obtained by testing the stability, specificity and reproducibility of the immunosensor. Therefore, it can be concluded that the as-proposed immunosensor has the application potential of clinical analyze of hIgG in human serum.

Preparation of Reduced Graphene Oxide Sheets with Large Surface Area and Porous Structure for High-Sensitivity Humidity Sensor

Humidity sensors provide environmental conditions suitable for several applications. However, they suffer from a limited reliable range originating from the low electrical conductivity and low water-sensitive sites of humidity-sensing materials. In this study, we developed high-sensitivity humidity sensors based on holey-reduced graphene oxide (HRGO) with a large surface area (274.5 m2/g) and an abundant pore structure. HRGO was prepared via the H2O2-etching-reaction-assisted hydrothermal processing of graphene oxide sheets. The resulting humidity sensor exhibited high sensitivity (−0.04317 log Z/%RH, R2 = 0.9717), a fast response time (<3 s), and long-term stability over 28 days. The impedance responses of the humidity sensor were almost similar between the mechanically standard and bent states. Furthermore, electrochemical impedance spectroscopy was performed to understand the humidity-sensing mechanism of the HRGO materials.