查找使用阿拉丁产品的科研文献

Hydrogen-Bonding Assembly of Rigid-Rod Poly(p-sulfophenylene terephthalamide) and Flexible-Chain Poly(vinyl alcohol) for Transparent, Strong, and Tough Molecular Composites

Mao Peng,Guohua Xiao,Xinglei Tang,Yang Zhou

Molecular composites comprising poly(p-sulfophenylene terephthalamide) (sPPTA), a sulfonated polyaramid rigid-rod polyelectrolyte, and flexible-chain poly(vinyl alcohol) (PVA) were prepared by a green and easy-to-scale-up water casting method. Influence of sPPTA on the microstructure and properties of the molecular composites was systematically investigated. Fourier transform infrared spectroscopy confirms the existence of hydrogen bonding between sPPTA and PVA. Wide-angle X-ray diffraction patterns do not show the characteristic of neat sPPTA crystalline aggregates in the composites even when the sPPTA content is as high as 33 wt %, suggesting that the strong interaction between sPPTA and PVA prevents the self-aggregation of sPPTA and leads to the formation of PVA/sPPTA complexes inside the composites. Transmission electron microscopy shows that sPPTA has good compatibility with PVA, and nanoscale fibril-like supramolecular assemblies dispersing uniformly in the composites become observable with the increase of sPPTA content. Moreover, the PVA/sPPTA complexes have a strong effect on the melt point, crystallinity, mechanical properties, and thermal stability of PVA. The PVA/sPPTA composites exhibit both high strength and high ductility. When the content of sPPTA is 5 wt %, the PVA/sPPTA composite exhibits the best mechanical properties, with a tensile strength of 169 ± 13 MPa, which is 54% higher than that of neat PVA (110 ± 10 MPa). Surprisingly, the reinforcement factor is even superior to that of multiwalled carbon nanotubes, vapor grown carbon fibers, and nanodiamonds previously reported for the reinforcement of PVA nanocomposites. Moreover, the PVA/sPPTA molecular composites have a relatively low modulus but a much larger elongation at break than prefabricated nanocomposites, showing good ductility. The strong and tough PVA/sPPTA molecular composites can be potentially used as high performance membranes or fibers in the future.

Three-phases Fe3O4@TiO2-P(VDF-HFP) composite films with high energy storage density at low filler fraction under low operating electric field

Shixin Wei,Qiong Fu,Yang Liu,Qian Ji,Yafei Hou,Laihui Luo,Weiping Li

An enhanced energy storage ability, under a low operating electric field, was achieved in Fe3O4@TiO2-P(VDF-HFP) composite films. The low conductivity TiO2 layer was coated onto the high polarization Fe3O4 to construct Fe3O4@TiO2 core–shell fillers for decreasing filler fraction and alleviating conductivity contrast. For instance, the 2 vol.% Fe3O4@TiO2-P(VDF-HFP) film shows a discharged energy density and energy efficiency of 8.6 J cm−3 and 61.7%, respectively, under a low operating electric field of 261.9 kV mm−1. The coated TiO2 and modified –OH groups not only restrict the adverse effects (such as high conductivity, easy agglomeration, etc) caused by Fe3O4, but also contribute greatly to the improvement of polarization and breakdown strength, leading to a significantly improved energy storage performance. Additionally, the present work might possess great potential applications for energy storage owing to the low filler fraction, simple, and low electric filed operation.

Batch and fixed-bed column study for p-nitrophenol, methylene blue, and U(VI) removal by polyvinyl alcohol–graphene oxide macroporous hydrogel bead

Chen Dan,Zhou Jun,Wang Hongyu,Yang Kai

There is an increasing need to explore effective and clean approaches for hazardous contamination removal from wastewaters. In this work, a novel bead adsorbent, polyvinyl alcohol–graphene oxide (PVA-GO) macroporous hydrogel bead was prepared as filter media for p -nitrophenol (PNP), dye methylene blue (MB), and heavy metal U(VI) removal from aqueous solution. Batch and fixed-bed column experiments were carried out to evaluate the adsorption capacities of PNP, MB, and U(VI) on this bead. From batch experiments, the maximum adsorption capacities of PNP, MB, and U(VI) reached 347.87, 422.90, and 327.55 mg/g. From the fixed-bed column experiments, the adsorption capacities of PNP, MB, and U(VI) decreased with initial concentration increasing from 100 to 400 mg/L. The adsorption capacities of PNP, MB, and U(VI) decreased with increasing flow rate. Also, the maximum adsorption capacity of PNP decreased as pH increased from 3 to 9, while MB and U(VI) presented opposite tendencies. Furthermore, the bed depth service Time (BDST) model showed good linear relationships for the three ions' adsorption processes in this fixed-bed column, which indicated that the BDST model effectively evaluated and optimized the adsorption process of PVA-GO macroporous hydrogel bead in fixed-bed columns for hazardous contaminant removal from wastewaters.

High Responsivity and High Rejection Ratio of Self-Powered Solar-Blind Ultraviolet Photodetector Based on PEDOT:PSS/β-Ga2O3 Organic/Inorganic p–n Junction

Hebin Wang,Hongyu Chen,Li Li,Yuefei Wang,Longxing Su,Wanpeng Bian,Bingsheng Li,Xiaosheng Fang

A high responsivity self-powered solar-blind deep UV (DUV) photodetector with high rejection ratio was proposed based on inorganic/organic hybrid p–n junction. Owing to the high crystallized β-Ga2O3 and excellent transparent conductive polymer PEDOT:PSS, the device exhibited ultrahigh responsivity of 2.6 A/W at 245 nm with a sharp cutoff wavelength at 255 nm without any power supply. The responsivity is much larger than that of previous solar-blind DUV photodetectors. Moreover, the device exhibited an ultrahigh solar-blind/UV rejection ratio (R245 nm/R280 nm) of 103, which is two orders of magnitude larger than the average value reported in Ga2O3-based solar-blind photodetectors. In addition, the photodetector shows a narrow bandpass response of only 17 nm in width. This work might be of great value in developing a high wavelength selective DUV photodetector with respect to low cost for future energy-efficient photoelectric devices.

An integrated strategy for corncob pretreatment and coproduction of furfural and monosaccharides based on p-toluenesulfonic acid and a deep eutectic solvent system

Liping Luo,Wenxuan Wu,Yanan Shen,Yuheng Tao,Liqun Wang,Qing Qing

High-value valorization of cellulose and hemicellulose fractions in lignocellulosic biomass is crucial for a feasible biomass refinery scheme. In this study, an integrated strategy was developed for pretreatment of corncob and coproduction of furfural and high-concentration fermentable sugars. The hemicellulose fraction in raw corncob was selectively extracted to produce a xylose-rich hydrolysate via pretreatment with dilute p-toluenesulfonic acid (p-TsOH) under optimal reaction conditions (0.5% p-TsOH, 160 °C, and 30 min). Thereafter, the xylose hydrolysate was subjected to catalytic conversion in a DES (TEBAC : LA = 1 : 4) system at 190 °C for 10 min. Notably, 78.6% furfural yield was achieved, and the corresponding xylose conversion was close to 100.0%. In addition, the pretreated corncob residue exhibited excellent enzymatic digestibility as the yields of reducing sugar and glucose were 90.7% and 97.0%, respectively, at a high solid loading of 12%. This proposed approach represents an integrated strategy for coproduction of multiple products from agriculture residues.

Gas Chromatography-Mass Spectrometric Analysis of Nematicidal Essential Oil ofValeriana amurensis P Smirn ex Kom (Valerianaceae) Roots and its Activity against Heterodera avenae

YC Li,H Ji,HT Li

Interface-Promoted Direct Oxidation of p-Arsanilic Acid and Removal of Total Arsenic by the Coupling of Peroxymonosulfate and Mn-Fe-Mixed Oxide

Ming-Kun Ke,Gui-Xiang Huang,Shu-Chuan Mei,Zhao-Hua Wang,Ying-Jie Zhang,Tian-Wei Hua,Li-Rong Zheng,Han-Qing Yu

As one of the extensively used feed additives in livestock and poultry breeding, p-arsanilic acid (p-ASA) has become an organoarsenic pollutant with great concern. For the efficient removal of p-ASA from water, the combination of chemical oxidation and adsorption is recognized as a promising process. Herein, hollow/porous Mn–Fe-mixed oxide (MnFeO) nanocubes were synthesized and used in coupling with peroxymonosulfate (PMS) to oxidize p-ASA and remove the total arsenic (As). Under acidic conditions, both p-ASA and total As could be completely removed in the PMS/MnFeO process and the overall performance was substantially better than that of the Mn/Fe monometallic system. More importantly, an interface-promoted direct oxidation mechanism was found in the p-ASA-involved PMS/MnFeO system. Rather than activate PMS to generate reactive oxygen species (i.e., SO4·–, ·OH, and 1O2), the MnFeO nanocubes first adsorbed p-ASA to form a ligand–oxide interface, which improved the oxidation of the adsorbed p-ASA by PMS and ultimately enhanced the removal of the total As. Such a direct oxidation process achieved selective oxidation of p-ASA and avoidance of severe interference from the commonly present constituents in real water samples. After facile elution with dilute alkali solution, the used MnFeO nanocubes exhibited superior recyclability in the repeated p-ASA removal experiments. Therefore, this work provides a promising approach for efficient abatement of phenylarsenical-caused water pollution based on the PMS/MnFeO oxidation process.

Selective hydrodeoxygenation of p-cresol as a model for coal tar distillate on Ni–M/SiO2 (M = Ce, Co, Sn, Fe) bimetallic catalysts

Liuyi Pan,Yulong He,Menglong Niu,Yong Dan,Wenhong Li

Ni–M/SiO2 with different binary metals M (M = Ce, Co, Sn, Fe) prepared by an incipient impregnation method was used in the hydrodeoxygenation (HDO) of low-temperature coal tar distillate, which is rich in phenolic compounds. p-Cresol, as a model compound of the distillate, was used to evaluate the activity and selectivity of BTX products on the series of reduced Ni–M/SiO2 catalysts in a fixed bed reactor. The properties of the catalysts were characterized by N2 adsorption–desorption, ICP-AES, XRD, H2-TPR, and XPS. Benzene and toluene as the direct deoxygenation (DDO) products and cyclohexane and methylcyclohexane as the hydrogenolysis (HYD) products were detected to evaluate the selectivity of the path in the deoxygenation process. In this series of catalysts, the order of reactivity was Ni–Ce > Ni–Sn > Ni–Co > Ni–Fe > monometallic Ni. Meanwhile, the addition of Ce and Co loaded in the Lewis acid sites of the catalyst affected the electron distribution of nickel atom and its atomic arrangement on the surface of the carrier. Compared to monometallic Ni, the DDO path become dominant on Ni–Ce and Ni–Co and the selectivity for BTX products increased from 58.8% to 77.4% and 71.1%, respectively. The binary metal Sn, unlike the former two metals, formed a Ni3Sn crystal form with Ni, which resulted in significant enhancement of the HYD path while obviously increasing the reactivity.

Fast, Sensitive, and Highly Selective Room-Temperature Hydrogen Sensing of Defect-Rich Orthorhombic Nb2O5–x Nanobelts with an Abnormal p-Type Sensor Response

Piaoyun Yang,Yijing Fan,Keyang Hu,Lei Jiang,Lun Tan,Zhao Wang,Ang Li,Shulin Yang,Yongming Hu,Haoshuang Gu

The research and development of low-power-consumption and room-temperature hydrogen sensors are of great significance for the safe application of hydrogen energy. Herein, orthorhombic Nb2O5–x nanobelts are prepared through a combined procedure of hydrothermal, ion exchange, and annealing treatment in Ar. The topological transformation process results in the formation of abundant surface defects including chemical defects such as Nb4+, oxygen vacancies, and disordered microregions, which lead to the abnormal p-type conducting and hydrogen sensing behavior. Moreover, the orthorhombic Nb2O5–x nanobelts exhibit fast and sensitive room-temperature hydrogen sensing performance, which shows greater advancement than the monoclinic, tetragonal, and hexagonal Nb2O5 one-dimensional (1D) nanostructures. The response time and lowest limit of detection of the as-fabricated room-temperature sensor decrease to 28 s and 3.5 ppm, respectively. The sensor also exhibits a highly selective hydrogen response against CO, CH4, ethanol, H2S, and NH3. The hydrogen response of the Nb2O5–x nanobelts can be attributed to the redox reaction between hydrogen and preadsorbed oxygens. The defective surface structure and the prolonged dimension of the nanobelts give rise to the highly reactive surface and the suppression of the negative nanojunction effect, which greatly improves the sensing performance. The orthorhombic lattice structure can also promote gas adsorption and diffusion behavior due to its specific catalytic and pathway effect. The results of this work can be helpful for the rational design and defect engineering of the Nb2O5-based 1D nanostructures for room-temperature hydrogen sensing applications.

Integrated N, P co-doped and dense carbon networks produced by a chemical crosslinking strategy: Facilitating high gravimetric/volumetric performance sodium ion batteries

Haijun Wang,Haocheng Yuan,Wenwei Zhan,Young-Seak Lee,Hee-Jae Shin,Xianbin Wei,Qing Cai,Jin-Le Lan,Yunhua Yu,Xiaoping Yang

Low-cost sodium ion batteries (SIBs) have shown hopeful perspective for large-scale energy storage systems . However, the development of carbon anode materials with high gravimetric and volumetric capacity is still a challenge. Herein, we propose a novel dense and N, P co-doped carbon derived from high density crosslinked bacterial cellulose (BC) with hexachlorocyclotriphosphazene (HCCP), which simultaneously combines high gravimetric and volumetric capacity. The as-prepared electrode demonstrates a high reversible capacity of 223 mAh g −1 at 0.05 A g −1 and superior rate performance (145 mAh g −1 at 10 A g −1 ) based on the overall electrode materials. The full SIBs with this electrode show a high energy density (156.1 Wh kg −1 ) as well as a high Coulombic efficiency in the potential range of 0–4.2 V. Density functional theory (DFT) calculation and kinetic analysis reveals that the synergistic effect of N, P co-doped configurations contributes to the superior sodium storage performance. Moreover, this electrode possesses high pressing density of 1.40 g cm −3 , which increases the volumetric capacity greatly (from 97.2 to 312.2 mAh cm −3 ). This work proposes a new idea towards the development of low-cost bacterial cellulose that can be used in practical applications for high gravimetric and volumetric performance SIBs.

Synthetic novel, convenient and eco-friendly Si/P/N synergistic treatment agent to improve the flame retardancy and thermal stability of cotton fabrics

Zhang Zheng,Kong Dezheng,Sun Heng,Sun Ling,Dong Chaohong,Lu Zhou

Abstract Modified flame retardant cotton fabrics were prepared by introducing a novel aminoethylpiperazine spirocyclic pentaerythritol bisphosphonate functional heptamethyltrisiloxane (ASPBH). The structure of the synthesized ASPBH was characterized using nuclear magnetic resonance ( 1 H and 31 P) and Fourier transform infrared spectra (FTIR). ASPBH successfully attached to the surface of cotton fibers, which was proved by the results of scanning electron microscope (SEM) combined with energy dispersive X-ray spectroscopy. The flame retardancy of ASPBH-treated cotton fabrics was further improved. The limiting oxygen index (LOI) value reached 30.4%, the residual char length was reduced to 7.5 cm, and there was no afterflame and afterglow. However, the LOI of untreated cotton fabric is only 18%, and the vertical burning test cannot be completed. Thermogravimetric analysis results showed that the modified cotton fabrics has excellent thermal stability, which can also be seen from SEM analysis of char residues. In addition, addition of ASPBH caused the peak heat release rate and total heat release decrease from 232.1 to 177.2 kW/m 2 and from 6.5 to 5.0 MJ/m 2 , respectively. And the treated cotton fabrics released less smoke than untreated ones during the combustion, which would greatly reduce combustion harm. Based on analysis of condensed phase at different temperatures, the thermal degradation mechanism of ASPBH on cotton fabrics was presumed. Graphic abstract A novel aminoethylpiperazine spiro pentaerythritol bisphosphonate functional heptamethyltrisiloxane (ASPBH) can be dissolved in a mixed solution of ethanol and water to prepare a flame retardant treating solution. The original cotton fabric was immersed for a certain period of time under certain conditions, then it was dried and solidified to complete finishing process. Treated cotton can form a stable SiO 2 char layer at high temperature and release less smoke.

New strumming sleight for old tunes: Exploration on the sorption mechanisms of Cd(II) by hydroxyapatite synthesized with different molar Ca/P ratios

Youwen Zhang,Haoyue Tang,Qi Xiao,Yu Zhang,Xiaolan Zhao,Shitong Yang

Hydroxyapatite (HAP) has been widely used for the preconcentration and stabilization of various heavy metal pollutants in both the water and soil environment. Nonetheless, there still exists a gap between its synthesis conditions, physicochemical properties and removal performances. Under such a research background, three HAP materials were synthesized via a modified co-precipitation approach by varying initial Ca/P molar ratios (i.e., 4/3, 5/3 and 6/3) and used for capturing toxic cadmium (Cd(II)) from an aqueous solution. According to the experimental results, the three synthesized HAP samples were all the Ca-deficient type and the actual Ca/P molar ratio was in the increasing order of HAP4/3 < HAP5/3 < HAP6/3. In particular, the HAP4/3 sample exhibited higher Cd(II) removal performance due to its higher specific surface area (SSA) value and abundant Ca-deficient sites. More than 93% of Cd(II) was removed within an extremely short period of 5 min and a complete removal was achieved at a prolonged contact time of 24 h. The sorption behavior of Cd(II) was independent of ionic strength variation and scarcely influenced by various inorganic electrolyte ions, low molecular weight organic acids (LMWOAs) and competing heavy metal ions . The desorption data of Cd(II)-containing HAP phases, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses pointed to a predominant removal mechanism of lattice incorporation with a minor contribution of inner-sphere surface complexation. The experimental findings demonstrated the significant application potential of Ca-deficient HAP material for the cost-effective treatment of Cd(II)-polluted water systems.