Multiporous Structure Research Articles

Hydrogen adsorption of O/N-rich hierarchical carbon scaffold decorated with Ni nanoparticles: Experimental and computational studies

Hierarchical carbon scaffold (HCS) with multi-porous structures, favoring hydrogen diffusion and physisorption is doped with 2–10 wt % Ni for storing hydrogen at ambient temperature. Due to N- and O-rich structure of melamine-formaldehyde resin used as carbon precursor, homogeneous distribution of heteroatoms (N and O) in HCS is achieved. 2 wt % Ni-doped HCS shows the highest hydrogen capacity up to 2.40 wt % H2 (T = 298 K and p (H2) = 100 bar) as well as excellent reversibility of 18.25 g H2/L and 1.25 wt % H2 (T = 298 K and p (H2) = 50 bar) and electrical production from PEMFC stack up to 0.7 Wh upon eight cycles. Computations and experiments confirm strong interactions between Ni and heteroatoms, leading to uniform distribution small particles of Ni. This results in enhancing reactive surface area for hydrogen adsorption and preventing agglomeration of Ni nanoparticles upon cycling. Ni K-edge XANES spectra simulated from the optimized structure of Ni-doped N/O-rich carbon using DFT calculations are consistent with the experimental spectra and suggest electron transfer from Ni to hydrogen to form Ni–H bond upon adsorption. Considering low desorption temperature (323 K), not only chemisorbed hydrogen is involved in adsorption mechanisms but also physisorption and spillover of hydrogen.

Recycled Energy Storage Materials for the Supercapacitors from Waste Coffee Sludge

Coffee is one of the largest agricultural products generally used in beverages. The international production of coffee is approximately 120 billion bags per year (60 kg per bag) from the International Coffee Organization. It corresponds to an annual production of approximately 8 million metric tons of coffee; therefore, coffee can be considered as a significant agricultural commodity. However, the majority of the produced coffee is disposed of waste sludge by beverage manufacturers. Herein, we report the use of graphitic porous carbon materials that have been derived from waste coffee sludge for developing an energy storage electrode based on a hydrothermal recycling procedure. Waste coffee sludge is used as a carbonaceous precursor for energy storage due to its lower cost, greater abundance, and easier availability as compared to other carbon resources. In addition, excluding the oil components, coffee sludge is mainly composed of cellulose-based materials with many heteroatoms (e.g., nitrogen, oxygen, and sulfur). It is considered good precursors for the fabrication of functionalized carbon materials. The unique graphite porous carbon production by hydrothermal carbonization of coffee sludge is particularly attractive as it addresses waste handling issues, offers a cheaper recycling method, and reduces the requirement for landfills. Therefore, we recycled the coffee slurry into hydrated carbon via sequential hydrothermal carbonization (HTC) as an activation process. The HTC reaction converts the cellulose-based biomass into hydrochar, bio-liquid, and gas at a relatively low temperature range (180°C~230°C). Hydrochar has various surface functional groups; so, it has been investigated for alternative fuels, carbon dioxide sequestration, and heavy metal immobilization for environmental remediation. During sequential hydrothermal activation, a porous and graphitic structure of the hydrochar can be developed, where these features are the most important characteristics of materials for electron accumulation. The porous and graphitic property of carbonaceous materials promotes electron accumulation for capacitive reactions. The electrical double-layer capacitive (EDLC) reaction has attracted considerable interest for next-generation energy storage systems such as supercapacitors. Our investigations revealed that the graphitic porous carbon, which is derived from spent coffee sludge, was employed in EDLCs by manipulating its unique microstructure which has a high hierarchical porous nature and graphitic edges. To activate the synthesized material, the dried hydrochar was mixed with 1 M KOH at a mass ratio of 1:3.5. The mixed sample was also heated at 700°C for 2 h in the hydrothermal reactor. After that, the activated hydrochar (AHC) was washed with pure water until a pH value of 7 was reached; subsequently, it was dried in an oven at 105°C for 24 h. After activation process, to gain deeper insights into the microstructure of HC and AHC regarding the specific surface area and pore size distribution, N2 adsorption/desorption isotherms were conducted. In Figure c, the TEM image of AHC has graphitized structure, which indicates easy pathways for ion and electron transport. AHC provides a higher electrochemical performance as an EDLC electrode than that demonstrated by the HC because of the high surface area (~1067 m2 g−1) and a hierarchical multi-porous structure of AHC as shown in Figure d. In addition, the conductivity of AHC is superior to that of HC; that is expected because AHC has a connected graphitized structure, which is not observed for HC, as confirmed by the TEM data (Figure a-c). The tangent to the curve in the low frequency region for AHC is higher than that for HC in Figure f. This indicates AHC has a better ion propagation and more ideal supercapacitive performance than HC. Figure a-c show the morphological differences due to the activation reaction, suggesting the existence of a well-developed hierarchical porous structure in AHC as compared to that the structure of HC. When the porous electrode is dipped into the electrolyte, the interconnections between the macropores not only provide sites for localization of the electrolyte, but also form pathways. The specific capacitance of the AHC based supercapacitors was 140 F g-1 in Figure e. Also, it demonstrated a good cyclic performance with 3% reduction over 1500 cycles at current density of 0.3 A g-1. Thus, AHC from waste coffee sludge could be an environmentally friendly technique associated with energy storage systems.This research was funded and conducted under the Competency Development Program for Industry Specialists of the Korean MOTIE, operated by KIAT (No. P0012453, Next-generation Display Expert Training Project for Innovation Process and Equipment, Materials Engineers). Figure 1

Synergistic engineering of defects and architecture in Co3O4@C nanosheets toward Li/Na ion batteries with enhanced pseudocapacitances

Abstract Constructing robust 2D−based energy storage nanomaterials by well−defined pore architectures and rational surface modification are critical yet daunting challenges for rechargeable alkali−ion batteries. Herein, a new−type 2D interwoven multi pores decorated Co3O4@N−doped carbon nanosheet with rich surface defects is proposed as lithium/sodium ion anodes for the first time. The combining experimental researches, microscopic structure characterization and dynamics analysis demonstrate that the multi porous structure provides large numbers of channels to accelerate Li+/Na+ transport, rational surface design creates abundant active sites for fast ions reactions, while robust carbon shell offers excellent ionic/electrical conductivity and structural integrity. The obtained bifunctional composites deliver superior rate performance and long−term cycle stability (~529 mA h g−1 after 2000 cycles in LIBs and ~166 mA h g−1 after 1700 cycles in SIBs) due to the synergistic contribution of the unique structure and surface defects. Furthermore, it still remains a high reversible capacity (>610 mA h g−1 after 1000 cycles) in full cell. Kinetic analysis reveals the designed anode exhibits prominent pseudocapacitive behavior, enabling ultra−fast lithium/sodium storage and ultrahigh−rate capability. This work offers valuable insights for developing high performance energy storage devices.

Interconnected Micro, Meso, and Macro Porous Activated Carbon from Bacterial Nanocellulose for Superior Adsorption Properties and Effective Catalytic Performance.

The porous carbon (bacterial cellulose (BC)-activated carbon (AC)(BA)) prepared via two-step activation of bacterial nanocellulose by treatments with potassium hydroxide (KOH) and then phosphoric acid (H3PO4) solutions showed superior adsorption properties and effective performance as catalyst support. BC-AC(BA) had an open and interconnected multi-porous structure, consisting of micropores (0.23 cm3/g), mesopores (0.26 cm3/g), and macropores (4.40 cm3/g). The BET surface area and porosity were 833 m2/g and 91.2%, respectively. The methylene blue adsorption test demonstrated that BC-AC(BA) was superior in its mass transfer rate and adsorption capacities. Moreover, BC-AC(BA) modified by H3PO4 treatment showed a significant enhancement of catalytic performance for dehydration of ethanol. At the reaction temperature of 250–400 °C, 30P/BC-AC(BA) gave ethanol conversion at 88.4–100%, with ethylene selectivity of 82.6–100%, whereas, high selectivity for diethyl ether (DEE) at 75.2%, at ethanol conversion of 60.1%, was obtained at the reaction temperature of 200 °C.

Nanoporous Anodic Alumina As a Three-dimensional Nanostructured material for the Remote Optical Sensing of Urea

Millions of people in the world suffer from some form of kidney disease [1]. Due to reduce the economic losses caused by this disease and also to improve the public health, the fabrication of a device to diagnose kidney disease is important for every government. Up to now, several biosensors have been reported for the determination of urea [2,3]. However, no of them is remote biosensor. The most advantage of the remote sensor is, analyzing the real samples without getting any fungal/virus/bacterial infection that can be in it. Infection. The interferometric reflectance spectroscopy (IRS) is one of the remote sensing devices. IRS is a physical method based on the interference of white light at porous thin substrates, which is used to investigate molecular interaction. This investigation is detected by the charge-coupled device (CCD) detector. Macroporous silicon (MPS) and nanoporous anodic alumina (NAA) are two of the interesting porous thin substrates for the fabrication of biosensor based on IRS [4-6]. However, NAA has become gradually influential in the IRS biosensors due to its high surface area, biocompatibility, easy functional ability, versatile, durable and low-cost substrate.Herein, we fabricated a remote optical biosensor for the determination of urea. For this purpose first, the self-orderednanoporous anodic alumina (NAA) was fabricated by electrochemical anodization of aluminum substrates in a two-step anodization process [7, 8]. The morphological characterization of the NAA was examined by SEM. The surface of NAA has a hexagonal multi-pore structure. The average diameter pore size of NAA was 41 nm. Then, the NAA pore walls were functionalized with 3-aminopropyl tri-methoxy silane (NAA-NH2). After that, the urease enzyme was immobilized to the pore walls of NAA-NH2 by the use of glutaraldehyde as cross-linker. After that, fluorescein 5(6)-isothiocyanate (FLITC) as the pH-sensitive optical probe was attached to urease enzyme to fabricate a novel urea and trypsin biosensor. The operation principle of the proposed biosensor is based on a change in the pH of the solution during the reaction of urease and urea and then change in the absorption properties of the FLITC. The reaction of urease with urea lets to increase the pH of its environment because of producing ammonia, which is basic. So, the absorption property of FLITC that is a pH-sensitive opt-probe will increase by increasing the urea in solution due to the increase of pH solution during urease/urea reaction. Consequently, the residence of light intensity that will be detected by the CCD detector in the presence of urea is less than in the absence of it. The proposed biosensor exhibited a good response to the concentration of urea in the range of 0.12 to 3.0 mM. The limit of detection (LOD) for urea was 0.06 mM (Fig.1).To examine its applicability in real sample analysis, the urease biosensor was used for the determination of urea in normal human urine with the standard addition method. Briefly, 1.0 mL of the filtered urine solution added to 9.0 mL of NaAC solution (0.1 M, pH 6.4) and then the solution was pumped into the analytical cell to be analyzed by NAA-NH-GLA-urease-FLITC. The concentration of urea was determined to be 192 mM. The recovery of the analysis was 92 %, considering the value determined by the fluorescent-based sensor [9].The NAA-NH-GLA-urease-FLITC exhibited good reproducibility in the detection of urea. The effect interfering compounds were also studied on the response of biosensor. No interference was observed with 0.1 mM of L-cysteine, dopamine, glucose, and nicotinamide adenine dinucleotide and common cations and anions (0.1 mM of Na+, Al+3, K+, Cl-, NO3 -, SO4 -2).The proposed biosensor exhibited good selectivity, linear range responsibility, and stability.References(1) https://www.worldkidneyday.org/2019-campaign/2019-wkd-theme/.(2) Mishra, G.K., Mishra, R.K., Bhand, S., 2010. Biosens Bioelectron.26, 1560-1564.(3) Parashar, U.K., Nirala, N.R., Upadhyay, C., Saxena, P.S., Srivastava, A., 2015. Appl Biochem Biotechnol. 176, 480-492.(4) Amouzadeh Tabrizi, M., Ferré-Borrull, J, Marsal, L. F., 2019. Biosens Bioelectron 137, 279-286.(5) Amouzadeh Tabrizi, M., Ferré-Borrull, J, Marsal, L. F., 2020. Biosens Bioelectron 137, 111828.(6) Ferré-Borrull, J, Pallarès, J, Macías, G, Marsal, L. F., 2014 Materials 7, 5225-5253.(7) Santos, A., Vojkuvka, L., Alba, M., Balderrama, V. S., Ferré‐Borrull, J, Pallarès, J., Marsal, L.F., Physica Status Solidi (a) 209, 2045-2048.(8) Santos, A., Macías, G., Ferré-Borrull, J., Pallarès, J., Marsal, L.F., 2012. Appl. Mater. Interfaces 4, 3584-3588.(9) Deng, H.-H., Li, K.-L., Zhuang, Q.-Q., Peng, H.-P., Zhuang, Q.-Q., Liu, A.-L., Xia, X.-H., Chen, W., 2018. Nanoscale 10, 6467-6473. Figure 1

Fabrication of a waterborne, superhydrophobic, self-cleaning, highly transparent and stable surface.

Superhydrophobic surfaces have received tremendous attention worldwide. However, the synthesis of a superhydrophobic surface possessing two paradoxical characteristic properties - stability and transparency, is a vital aspect that has been addressed in this paper. The surface was fabricated by an environmentally friendly process, which used distilled water for the dissolution of SiO2 nanoparticles in the presence of surfactants, instead of organic solvents. Moreover, the surface was transparent and had self-cleaning properties and stability. The optimal balance of roughness and multi-porous structure imparted excellent transparency to this surface. Importantly, both the conformal coating and the SiO2 nanoparticles embedded in the half solidified conformal coating contributed to the excellent stability, thus overcoming the paradox. The surface could withstand a temperature of 150 °C for 24 h and also different temperature regimes between 0-200 °C for 2 h. In addition, this surface could resist repeated scratches and abrasion as well as strong acids and alkali. The surface achieved its self-cleaning ability due to the introduction of surfactants containing the F element. This simple but novel strategy and surface have the advantages of high safety, low cost and environmental-friendliness.

Enhanced thermal performance of form-stable composite phase-change materials supported by novel porous carbon spheres for thermal energy storage

Abstract n-Octadecane/novel porous carbon composite phase-change materials (PCMs) containing a novel porous carbon as the supporting material for n-octadecane were successfully fabricated by vacuum impregnation. The novel porous carbon was first prepared using functionalized polystyrene nanoparticles as a template and soluble starch as a carbon source. The porous carbon spheres can adsorb n-octadecane, preventing them from leaking during the phase-change procedure, and providing them with high thermal conductivity as well as good mechanical and thermal stability. Results show that the novel porous carbon possesses a multi-porous and regular spherical structure with a specific surface area of 1100 cm2/g. Fourier-transform infrared spectroscopy and scanning-electron-microscopy images prove that n-octadecane/novel porous carbon composite PCMs were successfully prepared and exhibited a regular spherical profile. Differential scanning calorimetry reveals that the composite PCMs have an excellent energy storage property, and the latent heat can reach 170.5 J/g, which is higher than the theoretical value. Furthermore, the composite PCMs exhibited an outstanding thermal stability after 100 repeated thermal cycles, and the thermal conductivity were improved up to 0.631 W/(m∙K), which enhanced by 266% compared with n-octadecane. The composite PCMs also displayed a good shape stability without any leakage during heating at 40 °C. These results confirm that the composite PCMs are promising for thermal energy-storage application systems.

Controlled Focused Ion Beam Milling of Composite Solid State Nanopore Arrays for Molecule Sensing.

Various nanoscale fabrication techniques are elaborated to form artificial nanoporous/nanochannel membranes to be applied for biosensing: one of the most prevalent is the micro-electromechanical systems (MEMS) compatible focused ion beam (FIB) milling. This technique can be easily adopted in micro- and nanomachining process sequences to develop composite multi-pore structures, although its precision and reproducibility are key points in the case of these thick multi-layered membranes. This work is to demonstrate a comprehensive characterisation of FIB milling to improve the reliability of the fabrication of solid state nanopore arrays with precisely predetermined pore geometries for a targeted molecule type to be recognised. The statistical geometric features of the fabricated nanopores were recorded as the function of the process parameters, and the resulting geometries were analysed in detail by high resolution scanning electron microscope (SEM), transmission electron microscope (TEM) and ion scanning microscopy. Continuous function of the pore diameter evolution rate was derived from the experimental results in the case of different material structures, and compared to former dissentient estimations. The additional metal layer was deposited onto the backside of the membrane and grounded during the ion milling to prevent the electrical charging of dielectric layers. The study proved that the conformity of the pore geometry and the reliability of their fabrication could be improved significantly. The applicability of the developed nanopore arrays for molecule detection was also considered by characterising the pore diameter dependent sensitivity of the membrane impedance modulation based measurement method.

Crucial Factors for Seed-Directed Synthesis of CON-type Aluminoborosilicate Zeolites Using Tetraethylammonium

Designing efficient synthesis methodologies, without using expensive organic structure-directing agents (OSDAs), for industrially important zeolites is of high significance not only to realize their commercialization but also to control their structural properties. Herein, we present a systematic study on seed-directed synthesis of aluminoborosilicate CON-type zeolites using tetraethylammonium hydroxide (TEAOH) as a simple OSDA, by particularly focusing on the precise size control of CIT-1 seeds, which allowed us to improve the overall production efficiency and to reach the highest solid yield of 38 wt %. It is revealed that the use of a certain amount of seeds jointly with TEAOH is the key factor governing the synthesis, where seeds act as growth centers to promote the crystallization, while TEAOH stabilizes the structure by charge-compensating with framework atoms. These findings provide insight into the synthesis of multipore structures from simple OSDA, which can be further extended to many other systems currently requiring complex OSDAs.

Polyamide 6 and thermoplastic polyurethane recycled hybrid Fibres via twin-screw melt extrusion

The sorting of multi-component textile waste into individual components limit the recycling potential of textile waste. Thermo-mechanical processes can be applied to recycle mixed waste, without sorting, to extrude hybrid fibres. This research reports on the mixing of polyamide 6 (PA6) and thermoplastic polyurethane (TPU) polymers to produce hybrid fibres by melt extrusion process. Two different blending compositions; namely PA6–80 and PA6–50, were produced. SEM images show the development of interconnected multi-porous hybrid fibre structures with average PA6–80 and PA6–50 fibre diameter of 136 and 126 μm, respectively. Differential scanning calorimetry (DSC), TGA and ATR-FTIR results show the changes in the thermal and chemical properties of the blends, demonstrating the interactions that happen between PA6 and TPU. Mechanical testing shows properties of the novel hybrid fibres are in between that of the fibres spun from the constituent polymers. The multicomponent melt extrusion can be potentially applied to the mixed polymer waste.

Fabrication of a Porous Ni-Based Metal with a Multi-pore Structure by a Screen Printing Process

Porous metals are commonly considered as having relatively excellent characteristics, such as a large surface area, light, lower heat capacity levels, high toughness, and good permeability. Ni alloys have high corrosion resistance, good heat resistance and chemical stability for high-temperature applications. In this study, porous Ni-based metals for hydrogen reformer catalyst support are developed with Ni alloys, in this case Ni–Cr powder (28 μm), NiO powder (2 μm), and a fine Ni powder (< 1 μm). Ni–Cr powders are spread onto Al2O3 substrate by a printing process. Ni-based foam is then placed on the printed powder and a loading plate. These are sintered at 1200 °C under a high vacuum condition. The NiO powder and the fine Ni powder slurry are then screen-printed sequentially on the double structure (NiCr-coated Ni foam). In this study, the fine Ni powder is printed one, three, and five passes. The porous Ni alloys, which have double-pore structure, triple-pore structure and quadruple-pore structure, are fabricated by screen printing processes. With increased stacking of the pore structure, the porosity decreased from 86 to 82%, and the pore sizes decreased from 6.25 to 0.3 μm. The porosity and pore size of the multi-pore structure can be controlled by the size of powder and screen printing process.

3D multiporous Co,N co-doped MoO2/MoC nanorods hybrids as improved electrode materials for highly sensitive simultaneous determination of acetaminophen and 4-aminophenol

3D multiporous Co, N co-doped MoO2/MoC (3D Co,N-MoO2/MoC) nanorods hybrids were successfully synthesized via carburizing core-shell ZIF-67-cladded MoO3 nanorods precursor at high temperature. As-fabricated Co,N-MoO2/MoC nanorods coated glassy carbon electrodes (GCE) was demonstrated to possess superior electrocatalytic activity for the electro-oxidation of acetaminophen (AC) and 4-aminophenol (4-AP). Such excellent electrochemical performance was largely attributed to the synergistic effect of the unique multiporous structure, the optimal component and abundant active sites of the nanorods. The corresponding electrode reaction mechanisms were studied in detail in this article. Under optimal conditions, the linear detection ranges were 0.05–200.0 μmol/L for AC and 0.05–140.0 μmol/L for 4-AP, respectively, with the low detection limits of 0.013 μmol/L and 0.012 μmol/L. Furthermore, the 3D Co,N-MoO2/MoC/GCE revealed excellent sensitivity, good reproducibility, stability and anti-interference ability. The developed electrode was evaluated towards the detecting AC and 4-AP in biological fluids, environment water and pharmaceutical formulations with satisfactory recovery, which had a broad application prospect.

Excellent detection of H2S gas at ppb concentrations using ZnFe2O4 nanofibers loaded with reduced graphene oxide

Cost-effective fabrication of sensors and detection of ultralow concentrations of toxic gases are important concerns for environmental monitoring. In this study, the reduced graphene oxide (RGO)-loaded ZnFe2O4 nanofibers (ZFO-NFs) were fabricated by facile on-chip electrospinning method and subsequent heat treatment. The multi-porous NFs with single-phase cubic spinel structure and typical spider-net morphology were directly assembled on Pt-interdigitated electrodes. The diameters of the RGO-loaded ZFO-NFs were approximately 50–100 nm with many nanograins. The responses to H2S gas showed a bell-shaped behaviour with respect to RGO contents and annealing temperatures. The optimal values of the RGO contents and the annealing temperatures were found to be about 1.0 wt% and 600 °C, respectively. The response of the RGO-loaded ZnFe2O4 NFs to 1 ppm H2S gas was as high as 147 at 350°C while their cross-gas responses to SO2 (10 ppm), NH3 (100 ppm), H2 (250 ppm), C3H6O (1000 ppm), and C2H5OH (1000 ppm) were rather low (1.8−5.6). The high sensor response was attributed to formation of a heterojunction between RGO and ZnFe2O4 and due to the fact that NFs consisted of many nanograins which resulted in multi-porous structure and formation of potential barriers at grain boundaries.

In situ formation of a multiporous MOF(Al)@γ-AlOOH composite material: A versatile adsorbent for both N- and S-heterocyclic fuel contaminants with high selectivity

We report here for the first time an in situ green synthetic approach for the formation of a multiporous (mesoporous) composite, Al(OH)(1,4-NDC)@γ-AlOOH, via a direct hydrothermal reaction between 1,4-H2NDC (1,4-naphthalene dicarboxylic acid) and millimeter-sized porous γ-Al2O3 beads. This composite material has been well characterized using various analytical techniques. It has been used for the stationary solid phase adsorption of sulfur-containing (SCCs) and nitrogen-containing compounds (NCCs) from both a model oil and a real fluid cracking (FCC) oil. The adsorption capacities decreased in the order of benzothiophene > dibenzothiophene > 4,6-dimethyldibenzothiophene > thiophene for the SCCs and pyridine > quinoline > indole > acridine for the NCCs. The composite material exhibited chemical stability, mechanical strength and recyclability for both the model oil and the real FCC oil. It is an active heterogeneous adsorbent for heterocyclic SCCs and NCCs with a high selectivity for aromatics. By using 2 g of this material, 97.4% (Ci = 77 ppmwN) and 58.3% (Ci = 350 ppmwS) for NCCs and SCCs, respectively, were removed from 20 g of real FCC oil in 2 h at ambient conditions. The main factors accountable for this excellent adsorption are the multiporous structure of the material with its enhanced surface area and porosity, its unique structural interactions, specific pore size and the presence of unsaturated Lewis acid metal (Al) sites.

Highly efficient removal of Cu(II), Cd(II) and Pb(II) by carboxyl-modified multi-porous biochar

ABSTRACT The carboxyl-modified biochar derived from palm fiber was prepared through pyrolysis and oxidation. The adsorption behavior for Pb(II), Cu(II) and Cd(II) on the carboxyl-modified biochar was systematically investigated. The experimental results demonstrated that the carboxyl-modified biochar exhibited impressive adsorption performance owing to its multi-porous structure and abundant adsorption sites on the surface. The maximum adsorption capacities for Pb(II), Cu(II) and Cd(II) reached 218.5, 132.1 and 79.9 mg/g, respectively. The adsorption kinetics and isotherm could be well described by the pseudo-second-order model and the Langmuir isotherm model, respectively. After five successive adsorption/desorption cycles, the removal efficiency was still more than 90%, 86% and 83% for Pb(II), Cu(II) and Cd(II), respectively.

Improvement of Cr (VI) photoreduction under visible-light by g-C3N4 modified by nano-network structured palygorskite

In this paper, we firstly used the inorganic nano-network of palygorskite (IPAL) with multiporous structure fabricated from rigid nano-rods by ion beam bombardment to enhance the photoactivity of the graphitic carbon nitride (CN). Results of spectroscopy techniques show that the as-prepared sample (IPAL/CN) displays broader light absorption in the visible light region and low recombination of charge carriers. Photocatalytic illustrations of Cr (VI) (and methylene blue (MB)) in aqueous solution by IPAL/CN samples were investigated respectively. Results show that the IPAL/CN-1:6 composites exhibit a superior catalytic activity with 99.5% of Cr (VI) and 99.2% of MB removal efficiency in 100 min, which were almost 7.0 times and 9.5 times higher than that of pure CN, respectively. After four cycles, the IPAL/CN-1:6 exhibits great photoactivity. Moreover, the reaction can be conducted better under the low pH value of the solution, and the initial concentration can influence the reaction property. The theory of DLVO and zeta potential were used to analyze the dispersion effect on the samples. The higher photoactivity of the IPAL/CN samples could be attributed not only to the high adsorption capacity but also to the improved dispersion affected by the nano-network of IPAL. This study provides a new opportunity for the modification of photocatalyst by the inorganic nanomaterials formed easily by physical irradiation.

Adsorption of endocrine disrupting ethylparaben from aqueous solution by chemically activated biochar developed from oil palm fibre

ABSTRACTThe activated biochar (ABC) was prepared, characterized and examined the feasibility of removing ethylparaben (EP) from aqueous solution. The characterization results showed that ABC possessed multi-porous structure and high surface area. The adsorption isotherm was well fitted the Langmuir isotherm and the adsorption kinetic followed the pseudo-second-order model. The maximum adsorption capacity of EP onto ABC was 349.65 mg/g at 298 K. The adsorption capacity maintained 90.82% after five successive adsorption/desorption cycles. ABC possessed high adsorption capacity, usability and stability, which indicating that ABC has great potential to be a promising adsorbent for removal of EP from aqueous solution.

Chemoreception of Mouthparts: Sensilla Morphology and Discovery of Chemosensory Genes in Proboscis and Labial Palps of Adult Helicoverpa armigera (Lepidoptera: Noctuidae).

Siphoning mouthparts, consisting of proboscis and labial palps, are the exclusive feeding organs and important chemosensory organs in most adult Lepidoptera. In this study, the general morphology of the mouthpart organs and precision architecture of the proboscis was described in adult Helicoverpa armigera. Three major sensilla types with nine subtypes including three novel subtypes were identified. The novel sensilla styloconica subtype 2 was the only one having a multiporous structure, which may play olfactory roles. For further understanding of the chemosensory functions of mouthpart organs, we conducted transcriptome analysis on labial palps and proboscises. A total of 84 chemosensory genes belonging to six different families including 4 odorant receptors (ORs), 6 ionotropic receptors (IRs), 7 gustatory receptors (GRs), 39 odorant binding proteins (OBPs), 26 chemosensory proteins (CSPs), and 2 sensory neuron membrane proteins (SNMPs) were identified. Furthermore, eight OBPs and six CSPs were identified as the novel genes. The expression level of candidate chemosensory genes in the proboscis and labial palps was evaluated by the differentially expressed gene (DEG) analysis, and the expression of candidate chemosensory receptor genes in different tissues was further investigated by quantitative real-time PCR (qRT-PCR). All the candidate receptors were detected by DEG analysis and qRT-PCR, but only a small part of the OR or IR genes was specifically or partially expressed in proboscis or labial palps, such as HarmOR58 and HarmIR75p.1, however, most of the GRs were abundantly expressed in proboscis or labial palps. The reported CO2 receptors such as HarmGR1, GR2, and GR3 were mainly expressed in labial palps. HarmGR5, GR6, and GR8, belonging to the “sugar receptor” clade, were mainly expressed in proboscis or antenna and were therefore suggested to perceive saccharide. The results suggest that the mouthparts are mutually cooperative but functionally concentrated system. These works contribute to the understanding of chemical signal recognition in mouthpart organs and provide the foundation for further functional studies.

Facile on-chip electrospinning of ZnFe2O4 nanofiber sensors with excellent sensing performance to H2S down ppb level

ZnFe2O4 nanofiber gas sensors are cost-effectively fabricated by direct electrospinning on microelectrode chip with Pt interdigitated electrodes and subsequent calcination under different conditions to maximize their response to H2S gas. The synthesized nanofibers of approximately 30-100 nm in diameter show typical spider-net-like morphology of the electrospun nanofibers. The ZnFe2O4 nanofibers comprise many 10-25 nm nanograins, which results in multi-porous structures. Moreover, the nanofibers exhibit the single phase of cubic-spinel-structure ZnFe2O4. The density, crystallinity and grain size of ZnFe2O4 nanofiber that strongly affect gas-sensing properties can be optimized by controlling electrospun time, annealing temperature, annealing time and heating rate. Under optimal conditions, the ZnFe2O4 nanofiber sensors exhibit high sensitivity and selectivity to H2S at sub-ppm levels. Excellent gas-sensing performances are attributed to effects of multi-porous structure, nanograin size and crystallinity, which is explained by the sensing mechanisms of ZnFe2O4 nanofiber sensors to H2S gas.

In Situ Generated Ni3Si2O5(OH)4 on Mesoporous Heteroatom-Enriched Carbon Derived from Natural Bamboo Leaves for High-Performance Supercapacitors

Hybrids consisting of mesoporous carbon and uniform sized, regular morphology and even distributed metal silicate have been a challenge, although they are a potential promising material for electrochemical supercapacitor. In this work, we have synthesized a hybridized supercapacitor electrode of layered nickel silicate Ni3Si2O5(OH)4 nanoparticles on the porous carbon derived from calcined natural bamboo leaves (C-SiO2). The good combination of C-SiO2 and in situ generated layered nickel silicate, which turned out to be an outstanding electrode, demonstrates high specific surface area, multiporous structure, good electrical conductivity, and prominent electrochemical performance. For instance, the obtained C-NiSi-3 showed 132.4 F g–1 at a current density of 0.5 A g–1 and significantly maintained 100% after 10000 cycles. Furthermore, a flexible all-solid-state asymmetric supercapacitor device was assembled by C-NiSi-3 and Ni(OH)2. The device was suited to various bending angles and achieved a high capacitan...