Impregnation Concentration Research Articles

Pyrolysis characteristics and hydrogen production mechanism of biomass impregnated with transition metals

The application of metal impregnation pretreatment to improve the quality of biomass pyrolysis gas production is considered as a promising upgrading technology. Transition metals have been well developed for the unique structural characteristics. After impregnation pretreatment, the product distribution of biomass pyrolysis was changed, and the transfer path of H atoms and the formation mechanism of H2 can be revealed through analysis. The effects of impregnation pretreatment with three different transition metals (iron, cobalt, and nickel) on the pyrolysis characteristics of corn straw were evaluated in this work. Three transition metal solutions with concentrations of 0.5 M, 1 M, and 2 M were used to explore the influence of impregnation concentration on the yield and composition of the pyrolysis products. The results showed that iron promoted the formation of liquid products, whose proportion increased by 37.29% upon increasing the impregnation solution concentration. The addition of cobalt and nickel led to more pyrolysis gas generation. When the impregnation solution concentration was greater than 0.5 M, the gas production rate exceeded 45 wt%. Nickel simultaneously promoted the generation of H2 and CH4 in pyrolysis gas, whose yields were increased by 63% and 20% respectively compared with raw materials. Py-GC/MS analysis showed that Co-CS had strong decarboxylation characteristics during pyrolysis. Metal impregnation decreased the content of aromatic compounds in tar, which increased the stretching vibrations of C-H bonds in char. Ring-opening rearrangements of polycyclic aromatic hydrocarbons were promoted, which formed more -H. Nickel catalyzed the removal of CH3 and H groups and the rearrangement of C-O in volatile products, which formed more H2 and CH4. These findings provide an avenue to optimize the metal impregnation conditions to produce hydrogen via biomass pyrolysis.

An economical preparation strategy of magnetic biochar with high specific surface area for efficient removal of methyl orange

Magnetic biochar (MBC) was obtained from pepper straw by impregnation-microwave pyrolysis method. The pyrolysis temperature and FeCl3 impregnation concentration were investigated on the structural properties of MBC and the adsorption of methyl orange (MO) in water. Characterization results showed that pyrolysis temperature and iron species significantly increased the specific surface area of MBC, which could reach the maximum of 2038.61 m2/g, and also provided more active adsorption sites by promoting the generation of graphitized structures and surface polar functional groups. MBC0.2–900 was selected as the adsorbent for MO with the maximum adsorption capacity reached 437.18 mg·g−1, 3.4 times higher than the virgin biochar. The adsorption process was dominated by chemisorption as well as spontaneous and exothermic. The adsorption mechanisms included pore-filling interaction, π-π EDA interaction, electrostatic interaction, hydrogen bonding, and Lewis acid-base electron interaction. In addition, MBC also exhibited excellent separability and reusability as a low-cost adsorbent. This study provided some theoretical foundation and technological support for producing high-performance biochar and developing pollutant removal technology in wastewater.

Regulating the concentration of silica sol to prepare high thermal insulation ceramic nanofiber aerogel composites

Abstract Ceramic aerogels can maintain excellent thermal insulation performance under extreme conditions due to their outstanding pore structure and specific surface area. However, the current application of ceramic aerogels is limited by their brittleness, easy collapse of the structure under external forces, and insufficient mechanical properties. In this study, ceramic nanofiber aerogels prepared by PEO as a polymer were used as building blocks, and silica sol was selected as a high-temperature binder. Through the sol impregnation-atmospheric pressure drying method and calcination treatment, we obtained ceramic nanofiber composites with excellent performance. It is found that when the impregnation concentration is 0.4wt%, the thermal conductivity at room temperature is as low as 27 m W·m-1·K-1, the cold surface temperature at 800°C is as low as 255°C, the tensile strength at 20% tensile strain is as high as 400 kPa, and the compressive strength at 80% compressive strain is as high as 32 kPa. Compared with the traditional ceramic fiber aerogel material, the material exhibits excellent high-temperature insulation performance and mechanical properties, which greatly broadens the application scene of ceramic aerogel.

Removal of microbial aerosol using titania/chitosan composites in air conditioning systems

The humid environment of the air conditioning system promotes the growth of microorganisms on the filter media. Using filter media with antibacterial properties can solve this problem. As a photocatalytic material, TiO2 is often added to certain products as an antimicrobial. Chitosan (CS) is an antibacterial substance that can be processed into fibers, so it can be considered as a substitute for polypropylene (PP) fiber, which is currently commonly used as a filter medium. Unlike previous studies, this study used an air duct experiment system to simulate the operating conditions of air conditioning systems, and TiO2 was supported by CS and PP fiber, respectively. Results show that TiO2/CS exhibited better filtration and antibacterial properties at a 3% TiO2 impregnation concentration. When the basic weight of CS is 190 g/m2, the filtration efficiency can reach 96.8% with only 6 W ultraviolet, but the pressure drop is only 28 Pa. At the same time, the survival of bacteria on CS filter media is about 60% lower than that on PP and bacterial shedding is decreased by more than 35%. Due to the excellent filtration and antibacterial properties of TiO2/CS composite, its use in air conditioning systems will be of interest.

Hydroxyethylidene diphosphonic acid‐modified starch‐based flame retardant in improving the flame retardancy of insulating paper

AbstractIn order to improve the flame‐retardant performance of insulating paper and reduce the fire risk, hydroxyethyl diphosphate and dicyandiamide were used to modify starch to prepare a new starch‐based flame retardant (SHPD). The combustion, mechanical, and electrical properties of SHPD treated flame‐retardant insulating paper were investigated. The results showed that when the impregnation concentration of SHPD was 25.0%, the limiting oxygen index of the insulating paper was increased from 18.3% to 38.3% and reached the level of UL‐94 V‐0. The tensile index and burst index of the flame‐retardant insulating papers were only 10.17% and 12.5% lower than that of the control insulating paper. The ring crush strength and alternating current breakdown strength in air of the flame‐retardant insulating papers were 63.3% and 1.8% higher than that of the control insulating paper. The SHPD flame retardant has a good application prospect in insulating paper.

Optimal fabrication of carbon paper by different lengths of chopped carbon fibers and its enhanced performance in proton exchange membrane fuel cell

Carbon paper as a macroporous substrate of gas diffusion layer in proton exchange membrane fuel cells directly impacts the output performance of cells. In this study, we present a straightforward strategy to improve the overall performance of carbon paper by mixing short/long (6mm/10 mm) chopped carbon fibers at an optimal concentration of phenolic resin. The results show that incorporating longer carbon fibers can increase the porosity, conductivity, gas flux, and mechanical properties of carbon paper. The membrane electrode assembly achieved a peak power density of 1182.61 mW cm−2 at 60% RH using carbon paper with a long carbon fiber content of 40 wt% and an impregnation concentration of 10 wt%. This outperforms commercially available carbon paper. Based on electrochemical impedance spectroscopy results, it was confirmed that our carbon paper had a lower mass transfer resistance of only 32.17 mΩ cm−2 under conditions of 2 A cm−2 and 60% RH. This was due to its sparser three−dimensional network-like pore structure which was created by mixing different lengths (6mm/10 mm) of carbon fibers. This work provides new insights into preparing high−performance carbon papers.

Arsenic removal from coal-fired flue gas by metal oxides modified wood chips coke: Experimental and DFT study

Coal-fired power plant is one of the main anthropogenic arsenic emission sources, where gaseous As2O3 is the main form in the flue gas to the atmosphere. In this work, a series of metal salt impregnated wood chips coke (Me-BC) were developed for As2O3 removal from flue gas, which selected BC with low cost and high arsenic removal potential as the carrier and modified by metal nitrate through impregnation and pyrolysis to load active components. The results indicate that As2O3 removal performance of the Me-BC obeys Fe-BC-0.15 > BC > Al-BC-0.15 > Ca-BC-0.15 > K-BC-0.15 under the basic flue gas composition (N2 + O2 + CO2) at 150℃, with the highest As2O3 removal capacity (141.5 μg/g) and efficiency (92.9%) for Fe-BC-0.15 compared to 92.4 μg/g, 60.7% of the BC. The arsenic removal ability of Fe-BC firstly increases and then decreases as Fe(NO3)3 impregnation concentration increases with its maximum value at 0.15 mol/L. Generally, the NO has a significant inhibitory effect on the arsenic removal of Fe-BC-0.15 due to consumption of surface active oxygen species by or the competitive adsorption between NO and As2O3. Low-concentration SO2 complete with As2O3 for the adsorption on active sites while high-concentration SO2 will promote SO3 and Oβ formation which benefits for As2O3 capture. Overall, Oɑ and Oβ and C-O play an important promoting role in the arsenic removal by adsorbents. DFT calculations indicates that C-O have strongest adsorption energy for As2O3 among oxygen-containing functional groups. The adsorption of SO2 and NO on naked BC and BC-O is easier than As2O3. Both Fe2O3 and BC play an important role in the arsenic removal process by Fe-BC-0.15.

Leachability of Fast-Growing Wood Impregnated with Low Concentrations of Furfuryl Alcohol

Furfurylation can effectively improve the quality of fast-growing wood, but its leachability is unclear. In this study, fast-growing poplar (Populus sp.) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) were impregnated with low concentrations of 5%–20% furfuryl alcohol (FA), and the chemical and microscopic changes during leaching tests were analyzed by UV spectra and confocal laser scanning microscopy (CLSM). The results show that FA impregnation can regulate the weight percentage gain, but its effectiveness in regulating the cell wall bulking coefficient decreased as the impregnation concentration was increased. Impregnation with 15% and 20% FA showed no significant difference in the effect on volume swelling efficiency. The inverse relationship between the concentration of FA and the leaching rate was demonstrated by leaching tests, UV spectra, and CLSM. Notably, the leaching rate of poplar and Chinese fir wood was more than 30% when impregnated with 5% FA. Although the entirety of the furfuryl alcohol was deposited in the cell wall when impregnated with low concentrations of FA, the binding was not stable. The weight percentage gain of furfurylated Chinese fir was greater than that of poplar, but its leaching rate was lower, indicating that the cured furfuryl alcohol resin in poplar was not as stable as that in Chinese fir. Therefore, differences in tree species should be considered in low-concentration FA impregnation, as the improvement effect of concentrations below 10% on the properties of fast-growing wood is weak and the leaching rate of FA is significant.

Synthesis of Eugenol Ethyl Ether by Ethylation of Eugenol with Diethyl Carbonate over KF/γ-Al2O3 Catalyst

A KF/γ-Al2O3 solid base catalyst was prepared by wet impregnation and applied to the synthesis of eugenol ethyl ether (EEE) from eugenol and diethyl carbonate. By measuring the yield of eugenol ethyl ether, we investigated the effects of the catalyst active component, impregnation temperature, KF impregnation concentration, impregnation time, and calcination temperature on catalyst performance. The results showed that the KF/γ-Al2O3 catalyst can adequately facilitate the conversion of eugenol to EEE. The characterizations of the catalysts were examined by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterizations of EEE were examined by nuclear magnetic resonance spectrometry (H1-NMR), gas chromatography–mass spectrometer (GC-MS) and Fourier-transform infrared spectroscopy (FT-IR). It was found that the KF/Al2O3 catalyst (impregnation temperature 60 °C, KF impregnation concentration 40%, impregnation time 8 h, and calcination temperature 450 °C) showed the best effect. The yield of EEE remained 51.2% after recycling the supported catalyst three times.

A tailored and rapid approach for ozonation catalyst design

Catalytic ozonation is widely employed in advanced wastewater treatment owing to its high mineralization of refractory organics. The key to high mineralization is the compatibility between catalyst formulation and wastewater quality. Machine learning can greatly improve experimental efficiency, while fluorescence data can provide additional wastewater quality information on the composition and concentration of organics, which is conducive to optimizing catalyst formulation. In this study, machine learning combined with fluorescence spectroscopy was applied to develop ozonation catalysts (Mn/γ-Al2O3 catalyst was used as an example). Based on the data collected from 52 different catalysts, a machine-learning model was established to predict catalyst performance. The correlation coefficient between the experimental and model-predicted values was 0.9659, demonstrating the robustness and good generalization ability of the model. The range of the catalyst formulations was preliminarily screened by fluorescence spectroscopy. When the wastewater was dominated by tryptophan-like and soluble microbial products, the impregnation concentration and time of Mn(NO3)2 were less than 0.3 mol L−1 and 10 h, respectively. Furthermore, the optimized Mn/γ-Al2O3 formulation obtained by the model was impregnation with 0.155 mol L−1 Mn(NO3)2 solution for 8.5 h and calcination at 600 °C for 3.5 h. The model-predicted and experimental values for total organic carbon removal were 54.48% and 53.96%, respectively. Finally, the improved catalytic performance was attributed to the synergistic effect of oxidation (•OH and 1O2) and the Mn/γ-Al2O3 catalyst. This study provides a rapid approach to catalyst design based on the characteristics of wastewater quality using machine learning combined with fluorescence spectroscopy.

Performance optimization and kinetic analysis of HNO3 coupled with microwave rapidly modified coconut shell activated carbon for VOCs adsorption

As a typical carbon-based material, activated carbon (AC) has satisfied adsorption performance and is of great significance in the field of volatile organic compounds (VOCs) pollutants removal. In order to further reveal the optimization mechanism of AC adsorption performance, coconut shell-based AC was selected as the research object, and different concentrations of HNO3 coupled with microwave were used for rapid modification and activation. The characteristic changes of pore structure and surface chemical of AC before and after rapid modification were analyzed, and the performance changes of VOCs absorption were discussed from the perspective of reaction kinetics. The pore structure and surface chemical properties of before and after modification were analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmeta-Teller (BET) analysis, Fourier Transform Infrared Spectroscopy (FTIR), and Boehm titration. The results showed that HNO3 coupled with microwave could significantly eliminate impurities in the pores of AC. After impregnation in HNO3 at a concentration of 1.5 mol L−1 and under microwave irradiation of 900 W, the number of micropore on the surface of samples increased slightly. When the impregnation concentration of HNO3 continued to increase, the two adjacent pore structures of the samples merged, which lead to a large decrease in the number of micropore and a corresponding increase in the proportion of mesoporous. Meanwhile, the specific surface area SBET of the modified NAC-6 sample increased to 1,140.40 m2 g−1, and the total acidic oxygen-containing functional groups on the surface increased by 0.459 mmol g−1 compared to that of the unmodified raw carbon. Furthermore, by analyzing the experimental results of formaldehyde adsorption on AC samples, it was concluded that the saturated adsorption capacity of the modified NAC-6 sample was 43% higher than that of the raw carbon. This study provides a more convenient and faster modification method for AC in the field of gas phase pollutants purification, which is helpful to realize the practical engineering application of AC with high efficiency, energy saving and sustainable.

Fabrication of SiCN(O) Aerogel Composites with Low Thermal Conductivity by Wrapping Mesoporous Aerogel Structures over Mullite Fibers.

Silicon-based ceramic aerogels obtained by the polymer pyrolysis route possess excellent thermophysical properties, but their poor mechanical properties limit their broader applicability in thermal insulation materials. Herein, SiCN(O) ceramic aerogels were prepared under the toughening effect of a crosslinker (hexamethylene diisocyanate, HDI), which maintains the structural integrity of the aerogel during the wet gel-to-aerogel conversion. The aerogel maintained a high surface area (88.6 m2 g-1) and large pore volume (0.21 cm3 g-1) after pyrolysis. Based on this, mullite-fiber-reinforced SiCN(O) aerogels composites with outstanding thermal insulation properties and better mechanical performance were synthesized via ambient pressure impregnation. Furthermore, the effect of the impregnation concentration on the mechanical and insulation properties of the composites was investigated. The results revealed that the composite prepared with a solution ratio of 95 wt.% exhibited a low density (0.11 g cm-3) and a low thermal conductivity (0.035 W m-1 K-1), indicating an ~30% enhancement in its thermal insulation performance compared to the mullite fiber; the mesoporous aerogel structures wrapped on the mullite fibers inhibited the gas thermal conduction inside the composites.

Preparation of Pr2NiO4+δ-La0.6Sr0.4CoO3-δ as a high-performance cathode material for SOFC by an impregnation method

As a Ruddlesden-Popper (RP) phase solid oxide fuel cell (SOFC) cathode material, Pr2NiO4+δ (PNO) is a critical challenge for SOFC commercialization due to the lack of oxygen vacancies and insufficient redox reaction (ORR) activity. In this paper, various concentrations of La0.6Sr0.4CoO3-δ (LSC) nanoparticles are coated on the surface of PNO by an impregnation method, and the ORR kinetics of PNO is found to be improved by constructing a composite cathode with heterointerfaces. The formation of the heterointerface effectively enhances the transfer of interstitial oxygen in the PNO and the oxygen vacancies in LSC, which can promote the conduction of O2− in the cathode and thus improves the ORR activity of the material. When the impregnation concentration of LSC reached CLSC = 0.2 mol L−1, the ORR activity can reach the highest level. At 700 °C, the area-specific resistance of PNO-LSC reaches 0.024 Ω cm2, which is 83.4% lower than that of PNO (0.145 Ω cm2). And the peak power density of PNO-LSC reaches 0.618 W cm−2, which is 1.89 times larger than that of PNO (0.327 W cm−2). Therefore, the construction of composite cathodes with heterointerfaces via impregnation provides an alternative strategy for enhancing the ORR activity of the cathode materials in SOFC.

Oxygen plasma-assisted contra-diffusion self-assembly of covalent organic framework pervaporation membranes for organic-solvent dehydration

Pervaporation is considered to have great potential for application in the field of organic-solvent dehydration. In this study, a type of keto-enamine-linked covalent organic framework TpPa (synthesized using the Schiff-base reaction of 1,3,5-triformylphloroglucinol [Tp] with p-phenylenediamine [Pa]), was fabricated on commercial polyacrylonitrile (PAN) ultrafiltration membranes through an oxygen-plasma assisted contra-diffusion self-assembly strategy for organic-solvent dehydration. The PAN membranes with a glycerol exhibited a better separation factor for dehydration of organic solvents than those without a glycerol layer. The influence of oxygen plasma and glycerol on the formation of the TpPa membrane was investigated. The best plasma treatment condition and optimum glycerol impregnation concentration were determined as a device power of 60 W and 30 wt%, respectively. Defect-free TpPa membrane formation took only 24 h. The as-prepared TpPa membrane exhibited a separation factor of 1491 and a high permeation flux of 2530 g m−2 h−1 for a 90 wt% isopropanol–water mixture. The separation performance of the TpPa membrane was stable for >100 h, exhibiting great potential in organic-solvent dehydration.

Investigation on water vapor adsorption performance of carbon based composite adsorption material ACF-silica sol-LiCl

The composite adsorption material ACF-silica sol-LiCl (ASL) is prepared by impregnating activated carbon fiber (ACF) with silica sol and LiCl to improve the water vapor adsorption performance. The silica sol provides support to the soft ACF and solidifies it. The silica sol also increases the adhesion area in the ACF for the LiCl. The LiCl can effectively improve the water vapor adsorption performance of the ACF. The adsorption performance of the ASL is optimum when the LiCl impregnation concentration is 430 mg/L. Scanning electron microscope images show that the silica sol and LiCl fill the fibers pores and spaces between the fibers in the ACF after impregnation. And adsorption kinetics of the ASL is characterized using a linear driving force (LDF) model and experiments. Results show that ASL has a high dynamic water absorption rate and adsorption rate coefficient (k). The k of the ASL reaches 1.58 × 10−4−2.05 × 10−4, which is 0.27 × 10−4−0.59 × 10−4 higher than that of the ACF. Meanwhile, the results of water vapor isothermal adsorption tests show that the impregnation of silica sol and LiCl increases the hydrophilicity of the ACF, and thus greatly enhances its water vapor adsorption capacity. The adsorption capacity of the ACF is almost 0 at P/P0 < 0.2 and reaches a maximum of 0.5479 g/g at P/P0 = 0.65. The adsorption capacity of the ASL steadily increases with the relative pressure. When the relative pressure is close to 1, the adsorption capacity of the ASL reaches 2.2876 g/g, which is 2.67 times the maximum for the ACF.

Preparation of polydopamine-derived carbon-based nano-Fe catalysts and its catalytic conversion of toluene for hydrogen production

Carbon-based metal catalysts have excellent catalytic performance due to their porous structure and high dispersion of metal particles. In this paper, polydopamine (PDA) microspheres as carbon supports and Fe as the metal phase are used to synthesize carbon-based nano-Fe catalysts for catalytic cracking of toluene. The PDA derived carbon-based metal catalysts has more regular spherical shape when compared with biomass derived catalyst. The effect of activation steam concentration and Fe load on the characteristics of catalyst have been studied. As the concentration of activated steam increases from 7.5% to 15%, the specific surface area of the carbon support increases significantly, and the number of micropores also increases. When the Fe impregnation concentration is less than 5%, the dispersion of the metal particles on the surface of the carbon support is very good, and when the Fe impregnation concentration is greater than 5%, the metal particles on the surface of the carbon support begin to agglomerate. The introduction of this catalyst can significantly increase the removal efficiency of toluene and the hydrogen content of tail gas. The carbon-based metal catalysts before and after the toluene catalytic cracking experiments are characterized and found that the microporous structure played an important role in the removal of toluene, and the C─O functional groups and ─OH groups on the catalyst surface also played an important role in the catalytic process. The addition of Fe species can increase the specific surface area and promote the formation of surface functional groups, and can also strengthen the π-π interaction and electrostatic interaction on the catalyst surface. The lattice oxygen introduced by iron oxide can provide oxygen source for the oxidation reaction of toluene.

Non-metallic carbon-based catalysts for acetylene hydrochlorination: The effect of graphitization degree of carbonaceous material

Activated carbon fiber (ACF) carbon materials with different graphitization degrees were prepared by impregnation with iron salt solutions, where the graphitization degree was found to increase with the elevated impregnation concentration. Examining these materials for acetylene hydrochlorination demonstrated that their catalytic performances do not monotonically depend on the graphitization degree. Both density functional theory (DFT) calculations and experimental results revealed that the interface between the graphite layer and the support serves as the catalytic active site, and further clarified that the difference in the degree of exposure of the active interface results in the difference in catalytic activity.

Adsorption of chlortetracycline in aquaculture wastewater by lanthanum modified multi-walled carbon nanotubes

The lanthanum modified multi-walled carbon nanotubes (La-CNTs) prepared by an impregnation method were investigated for the adsorption of chlortetracycline (CTC) in aquaculture wastewater. The adsorbents were characterized by SEM, EDS, XRD and BET. The effects of some factors including La-containing impregnant concentration, adsorbent dosage, CTC adsorbate concentration, adsorption time, pH of the adsorbate solution and additional ions on the CTC adsorption by La-CNTs were investigated in detail, and the optimal adsorption conditions were determined. The adsorption kinetics obeyed the quasi-second-order kinetic model. The adsorption isotherms obeyed the Langmuir model and the fitted maximum capacity of La-CNTs for CTC adsorption was 55.3 mg/g.

Thiophene-functional hierarchical carbons for the removal of ionic and organic mercury in light hydrocarbon liquids: Synthesis, evaluation and adsorption mechanism

A simple synthesis of thiophene-functional zeolite-templated carbons (ZTCs) is proposed to remove ionic mercury (Hg2+) and organic mercury (Hgorg) from gasoline. Microporous zeolite (Beta) and mesoporous zeolite (MCM-41) were used to prepare porous carbon by impregnating with 2-thiophenemethanol (ThM) to explore the influence of template type on the quality of templated carbon. The amount of strong acidic sites in MCM-41 zeolite was more than Beta zeolite which promoted the catalytic polymerisation of the ThM in the pores structure of the zeolite and highly templated carbon was obtained. The impregnation concentration of ThM on the structure and functional groups of the samples was explored. It was found that increasing the concentration of ThM properly can promote the filling of zeolite pores by ThM and form more ordered templated carbons. In addition, the increased ThM promoted the formation of the S = O and C-O oxygen-containing functional groups. The optimal impregnation concentrations of ThM were 25% for B-Al (25%-B-Al-ZTC) and 75% for M−Al (75%-M−Al−ZTC). The 75%-M−Al−ZTC with sufficient S = O and C-O oxygen-containing functional groups showed excellent mercury adsorption capacity (617.49 μg/g) and a high intra-particle diffusion rate (294.10 h−1). The simultaneous adsorption of Hg2+ and Hgorg was also conducted and it was found that Hgorg had competitive adsorption for Hg2+ which led the total adsorption capacity to decrease. In addition, the 25%-B-Al-ZTC and 75%-M−Al−ZTC adsorbents had good regeneration ability and the adsorption capacity remained over 75% and 71% for Hg2+ and Hgorg after five desorption-sorption cycles, respectively. Thus, the new adsorbents with stable and efficient Hg removal performance have the potential for practical application by oil refineries.

Preparation and tensile conductivity of carbon nanotube/polyurethane nanofiber conductive films based on the centrifugal spinning method

Flexible conductive thin films have recently become a research area of focus in both academia and industry. In this study, a method of preparing nanofiber conductive films by centrifugal spinning is proposed. Polyurethane (PU) nanofiber films were prepared by centrifugal spinning as the flexible substrate film, and carbon nanotubes (CNTs) were used as the conducting medium, to obtain CNTs/PU nanofiber conductive films with good conductivity and elasticity. The effects of different CNT concentrations on the properties of the nanofiber films were investigated. It was found that the conductivity of the nanofiber conductive films was optimal when an impregnation concentration of 9% CNTs was used in the stretching process. Cyclic tensile resistance tests showed that the nanofiber conductive films have good durability and repeatability. Physical and structural property analysis of the CNT/PU conductive films indicate that the adsorption of the CNTs on the PU surface was successful and the CNTs were evenly dispersed on the surface of the matrix. Moreover, the CNTs improved the thermal stability of the PU membrane. The CNT/PU conductive films were pasted onto a human finger joint, wrist joint, and Adam’s apple to test the detection of movement. The results showed that finger bending, wrist bending, and laryngeal prominence movement all caused a change in resistance of the conductive film, with an approximately linear curve. The results indicate that the CNT/PU nanofiber conductive film developed in this study can be used to test the motion of human joints.