以一种腈纶基弱碱性离子交换纤维为材料,探讨了纤维型式（氯型、氢氧型）对吸附量和再生性能的影响。考察了溶液pH、温度对氯型纤维吸附量的影响,并进行相应的动力学实验。结果表明：转为氯型的纤维吸附与再生性能明显优于相应的氢氧型...以一种腈纶基弱碱性离子交换纤维为材料,探讨了纤维型式（氯型、氢氧型）对吸附量和再生性能的影响。考察了溶液pH、温度对氯型纤维吸附量的影响,并进行相应的动力学实验。结果表明：转为氯型的纤维吸附与再生性能明显优于相应的氢氧型纤维,该纤维在pH 2~3时吸附性能最好,温度越高吸附量越大。吸附过程符合准二级动力学模型（R2〉0.998）,吸附在30 min内基本达到平衡。纤维对六价铬的吸附容量可达376 mg g 1（pH=2,C0=300 mg L 1）,明显高于国外商品化的Fiban A-1离子交换纤维（152.9 mg g 1）;且经100次含铬电镀废水吸附再生循环后,六价铬去除率与纤维质量基本保持不变。展开更多
The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microsc...The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.展开更多
The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge f...The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge factor （fractional change in resistance per unit strain） of PAN-based carbon fibers is 1.38, which is lower than that of the commonly-used resistance strain gauge. These may due to that the electrical resistivity of carbon fibers decreases under tensile stress. In addition when the carbon fibers are stretched, the change of its resistance is caused by fiber physical dimension and the change of electric resistivity, and mainly caused by the change of physical dimension. The mechanical properties of carbon fiber monofilament were also measured.展开更多
The nanopore structures in precursors Four carbon-fiber precursors are prepared. They are crucial to the performance of PAN-based carbon fibers are bath-fed filaments （A）, water-washing filaments （B） hot-stretchin...The nanopore structures in precursors Four carbon-fiber precursors are prepared. They are crucial to the performance of PAN-based carbon fibers are bath-fed filaments （A）, water-washing filaments （B） hot-stretching filaments （C） and drying-densification filaments （D）. Synchrotron radiation small angle X-ray scattering is used to probe and compare the nanopore structures of the four fibers. The nanopore size, discrete volume distribution, nanopore orientation degree along the fiber axis and the porosity are obtained. The results demonstrate that the nanopores are mainly formed in the water-washing stage. During the processes of the subsequent production technologies, the slenderness ratio of nanopores and their orientation degree along the fiber axis increase further and simultaneously, the porosity decreases. These results are helpful for improving the performance of the final carbon fibers.展开更多
When the PAN-based stabilized fiber(PAN-SF) was converted to the carbon fiber, the effect of some of the carbonizing parameters on the structure and properties of the resulting carbon fibers, such as the molecular str...When the PAN-based stabilized fiber(PAN-SF) was converted to the carbon fiber, the effect of some of the carbonizing parameters on the structure and properties of the resulting carbon fibers, such as the molecular structure development, element contents, morphology and mechanical properties, was discussed. The results show that the carbonizing temperature, the purity of the inert gas and the de-oil pretreatment of the tiber have a great influence on them.展开更多
文摘以一种腈纶基弱碱性离子交换纤维为材料,探讨了纤维型式（氯型、氢氧型）对吸附量和再生性能的影响。考察了溶液pH、温度对氯型纤维吸附量的影响,并进行相应的动力学实验。结果表明：转为氯型的纤维吸附与再生性能明显优于相应的氢氧型纤维,该纤维在pH 2~3时吸附性能最好,温度越高吸附量越大。吸附过程符合准二级动力学模型（R2〉0.998）,吸附在30 min内基本达到平衡。纤维对六价铬的吸附容量可达376 mg g 1（pH=2,C0=300 mg L 1）,明显高于国外商品化的Fiban A-1离子交换纤维（152.9 mg g 1）;且经100次含铬电镀废水吸附再生循环后,六价铬去除率与纤维质量基本保持不变。
基金Sponsored by the Scientific Research Foundation of Harbin Institute of Technology(Grant No. HIT. 2003.57)
文摘The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.
基金Funded by the National Natural Science Foundation of China (No.10672128 and 50878170)
文摘The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge factor （fractional change in resistance per unit strain） of PAN-based carbon fibers is 1.38, which is lower than that of the commonly-used resistance strain gauge. These may due to that the electrical resistivity of carbon fibers decreases under tensile stress. In addition when the carbon fibers are stretched, the change of its resistance is caused by fiber physical dimension and the change of electric resistivity, and mainly caused by the change of physical dimension. The mechanical properties of carbon fiber monofilament were also measured.
基金Supported by National Natural Science Foundation of China (10835008)Knowledge Innovation Program of Chinese Academy of Sciences (KJCX3-SYW-N8)Momentous Equipment Program of Chinese Academy of Sciences (YZ200829)
文摘The nanopore structures in precursors Four carbon-fiber precursors are prepared. They are crucial to the performance of PAN-based carbon fibers are bath-fed filaments （A）, water-washing filaments （B） hot-stretching filaments （C） and drying-densification filaments （D）. Synchrotron radiation small angle X-ray scattering is used to probe and compare the nanopore structures of the four fibers. The nanopore size, discrete volume distribution, nanopore orientation degree along the fiber axis and the porosity are obtained. The results demonstrate that the nanopores are mainly formed in the water-washing stage. During the processes of the subsequent production technologies, the slenderness ratio of nanopores and their orientation degree along the fiber axis increase further and simultaneously, the porosity decreases. These results are helpful for improving the performance of the final carbon fibers.
文摘When the PAN-based stabilized fiber(PAN-SF) was converted to the carbon fiber, the effect of some of the carbonizing parameters on the structure and properties of the resulting carbon fibers, such as the molecular structure development, element contents, morphology and mechanical properties, was discussed. The results show that the carbonizing temperature, the purity of the inert gas and the de-oil pretreatment of the tiber have a great influence on them.
