To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NH...To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups(1.33 at%),specific surface area(1792.47 m2/g),and pore volume(1.18 cm^(3)/g).NHPC exhibited a higher Cr(Ⅵ)adsorption affinity than the HPC(without nitrogen doping)or the pristine loofah sponge carbon(LSC)did.The influence of process parameters,including pH,dosage,time,temperature,and Cr(Ⅵ)concentration,on Cr(Ⅵ)adsorption by NHPC were evaluated.The Cr(Ⅵ)adsorption kinetics matched with the pseudo-second-order model(R^(2)≥0.9983).The Cr(Ⅵ)adsorption isotherm was fitted with the Langmuir isotherm model,which indicated the maximum Cr(Ⅵ)adsorption capacities:227.27,238.10,and 285.71 mg/g at 298K,308K,and 318K,respectively.The model analysis also indicated that adsorption of Cr(Ⅵ)on NHPC was a spontaneous,endothermal,and entropy-increasing process.The Cr(Ⅵ)adsorption process potentially involved mixed reductive and adsorbed mechanism.Furthermore,computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI)(-0.84 eV)was lower than that of HPC(-0.51 eV),suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).展开更多
Three-dimensional(3D)porous piezoresistive sensors are widely used because of their simple fabrication and convenient signal acquisition.However,because of the dependence on organic skeleton materials and the complexi...Three-dimensional(3D)porous piezoresistive sensors are widely used because of their simple fabrication and convenient signal acquisition.However,because of the dependence on organic skeleton materials and the complexity of conductive coating preparation,the electrical and mechanical properties of 3D wearable piezoresistive sensors have gradually failed to accommodate many emerging fields.Here,a new flexible 3D piezoresistive sensor(NF3PS)with high sensitivity and a wide measurement range is proposed,which comprises a natural porous loofah as a flexible framework and carbon fiber/carbon nanotube(CF/CNT)multiscale composite as a conductive coating.Composed of cellulose and lignin,the irregular,porous loofah has excellent mechanical strength,elasticity,and toughness,ensuring a repeated compression/recovery behavior of the NF3PS.In addition,compared with the single-size carbon coating,the coupling of multiscale CF/CNT composite coating improves sensitivities over a range of pressures.The NF3PS demonstrates a sensitivity of 6.94 kPa^(-1) with good linearity in the pressure range of 0–11.2 kPa and maintains a sensitivity of 0.28 kPa^(-1) in an ultrawide measurement range of 11.2–84.6 kPa.Considering flexibility,robustness,and wide-ranging linear resistance variation,the feasibility of the NF3PS in human activity monitoring,mechanical control,and smart homes is verified.This work provides a novel strategy for a new generation of 3D flexible pressure sensors for improving sensitivity and measurement range and demonstrates attractive applications in wearable sensors.展开更多
锂硫电池由于具有较高的能量密度、较低的原材料成本而备受关注。本文采用三种不同的生物质材料高温热解制备了锂硫电池用生物质碳材料。采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、FT-IR、BET、TGA进行了物理表征,并采用恒流充放...锂硫电池由于具有较高的能量密度、较低的原材料成本而备受关注。本文采用三种不同的生物质材料高温热解制备了锂硫电池用生物质碳材料。采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、FT-IR、BET、TGA进行了物理表征,并采用恒流充放电性能测试、循环伏安测试(CV)、交流阻抗测试的手段,研究了不同来源的生物质材料和高温制备的生物碳材料在锂硫电池中电化学性能的发挥。研究结果表明,以丝瓜瓤高温热解得到的丝瓜基生物碳材料,具有最高的比表面积661.5 m^(2)·g^(-1)和最大的孔容积0.4228 cm^(3)·g^(-1),并作为载体与硫复合后得到了最优的电化学性能,其首周放电比容量为910.3 m Ah·g^(-1),循环200周后比容量仍可达到554.1 m Ah·g^(-1),显示出了良好的循环性能,同时也表现出了较好的倍率性能。展开更多
以丝瓜基因组DNA为模板,采用正交试验设计,对SRAP(sequence related amplified polymorphism,序列相关扩增多态性)反应体系中的4种关键因素(dNTPs、Taq酶、引物、模板)进行优化,建立了适合于丝瓜基因组SRAP分子标记的扩增体系:反应总体...以丝瓜基因组DNA为模板,采用正交试验设计,对SRAP(sequence related amplified polymorphism,序列相关扩增多态性)反应体系中的4种关键因素(dNTPs、Taq酶、引物、模板)进行优化,建立了适合于丝瓜基因组SRAP分子标记的扩增体系:反应总体积10μl,其中含Taq酶1.0U、模板DNA 50.00ng、dNTPs 0.3mmol/L、引物0.30μmol/L。该体系能很好地满足丝瓜基因组SRAP标记的要求,可应用于丝瓜的分子生物学研究。展开更多
基金funded by the National Natural Science Foundation of China(Grant No.41872169)the Project of Education Department of Henan Province(No.21A610002)the Innovation and entrepreneurship training plan for college students of Henan Province in 2020(No.S202011517004)。
文摘To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups(1.33 at%),specific surface area(1792.47 m2/g),and pore volume(1.18 cm^(3)/g).NHPC exhibited a higher Cr(Ⅵ)adsorption affinity than the HPC(without nitrogen doping)or the pristine loofah sponge carbon(LSC)did.The influence of process parameters,including pH,dosage,time,temperature,and Cr(Ⅵ)concentration,on Cr(Ⅵ)adsorption by NHPC were evaluated.The Cr(Ⅵ)adsorption kinetics matched with the pseudo-second-order model(R^(2)≥0.9983).The Cr(Ⅵ)adsorption isotherm was fitted with the Langmuir isotherm model,which indicated the maximum Cr(Ⅵ)adsorption capacities:227.27,238.10,and 285.71 mg/g at 298K,308K,and 318K,respectively.The model analysis also indicated that adsorption of Cr(Ⅵ)on NHPC was a spontaneous,endothermal,and entropy-increasing process.The Cr(Ⅵ)adsorption process potentially involved mixed reductive and adsorbed mechanism.Furthermore,computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI)(-0.84 eV)was lower than that of HPC(-0.51 eV),suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).
基金supported by the National Natural Science Foundation of China(Grant No.52175554)the Natural Science Foundation of Hebei Province(Grant No.F2021409007)+2 种基金the Hebei Province Foundation for the Returned Overseas Chinese Scholars(Grant No.C20220103)the School Research Fund Project(Grant Nos.ZDYY-2021-01,YKY-2022-33)。
文摘Three-dimensional(3D)porous piezoresistive sensors are widely used because of their simple fabrication and convenient signal acquisition.However,because of the dependence on organic skeleton materials and the complexity of conductive coating preparation,the electrical and mechanical properties of 3D wearable piezoresistive sensors have gradually failed to accommodate many emerging fields.Here,a new flexible 3D piezoresistive sensor(NF3PS)with high sensitivity and a wide measurement range is proposed,which comprises a natural porous loofah as a flexible framework and carbon fiber/carbon nanotube(CF/CNT)multiscale composite as a conductive coating.Composed of cellulose and lignin,the irregular,porous loofah has excellent mechanical strength,elasticity,and toughness,ensuring a repeated compression/recovery behavior of the NF3PS.In addition,compared with the single-size carbon coating,the coupling of multiscale CF/CNT composite coating improves sensitivities over a range of pressures.The NF3PS demonstrates a sensitivity of 6.94 kPa^(-1) with good linearity in the pressure range of 0–11.2 kPa and maintains a sensitivity of 0.28 kPa^(-1) in an ultrawide measurement range of 11.2–84.6 kPa.Considering flexibility,robustness,and wide-ranging linear resistance variation,the feasibility of the NF3PS in human activity monitoring,mechanical control,and smart homes is verified.This work provides a novel strategy for a new generation of 3D flexible pressure sensors for improving sensitivity and measurement range and demonstrates attractive applications in wearable sensors.
文摘锂硫电池由于具有较高的能量密度、较低的原材料成本而备受关注。本文采用三种不同的生物质材料高温热解制备了锂硫电池用生物质碳材料。采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、FT-IR、BET、TGA进行了物理表征,并采用恒流充放电性能测试、循环伏安测试(CV)、交流阻抗测试的手段,研究了不同来源的生物质材料和高温制备的生物碳材料在锂硫电池中电化学性能的发挥。研究结果表明,以丝瓜瓤高温热解得到的丝瓜基生物碳材料,具有最高的比表面积661.5 m^(2)·g^(-1)和最大的孔容积0.4228 cm^(3)·g^(-1),并作为载体与硫复合后得到了最优的电化学性能,其首周放电比容量为910.3 m Ah·g^(-1),循环200周后比容量仍可达到554.1 m Ah·g^(-1),显示出了良好的循环性能,同时也表现出了较好的倍率性能。
