A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natur...A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.展开更多
The assay of trace volatile low molecular weight(MW) compounds in human breath or in ambient atmosphere typically involves gas chromatography with flame ionization detection (FID). This paper introduced a direct assa...The assay of trace volatile low molecular weight(MW) compounds in human breath or in ambient atmosphere typically involves gas chromatography with flame ionization detection (FID). This paper introduced a direct assay which can overcome the difficulties of collection low concentration samples. In order to pre concentrate the trace low MW compounds, a small trapping column filled with absorbent must be used before thermal desorption of the collected samples onto chromatographic column(packed with Porapak Q) for separation. It has been proved that the characteristic of absorbent mainly influence the recoveries and the linear range of this method is from 0 05 ng to 5200 ng for pentane, methanol, ethanol and acetone.展开更多
以壳寡糖为诱导物处理烟草植株,利用高效液相色谱 电化学(库仑电极)阵列检测技术检测不同处理时间植物体内内源激素的变化情况及其他小分子物质的差异显示。所用色谱柱为HypersilBDSC18柱(4.6mmi d ×200mm,5μm),八通道电化学阵列...以壳寡糖为诱导物处理烟草植株,利用高效液相色谱 电化学(库仑电极)阵列检测技术检测不同处理时间植物体内内源激素的变化情况及其他小分子物质的差异显示。所用色谱柱为HypersilBDSC18柱(4.6mmi d ×200mm,5μm),八通道电化学阵列检测器(八个电极)的检测电势依次为-200,300,400,500,600,700,800,850mV。结果表明,茉莉酸(JA)和赤霉酸(GA)含量在用壳寡糖处理6h时达到高峰,吲哚乙酸(IAA)含量在处理8h时达到高峰。处理后烟草植株产生的其他一些未知的小分子物质尚有待定性和进一步考察其变化规律。展开更多
基金the National High Technology Research and Development Program of China(Grant No.2009AA063003)the National Nature Science Foundation of China(Grant No.20677039) for financial support
文摘A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.
文摘The assay of trace volatile low molecular weight(MW) compounds in human breath or in ambient atmosphere typically involves gas chromatography with flame ionization detection (FID). This paper introduced a direct assay which can overcome the difficulties of collection low concentration samples. In order to pre concentrate the trace low MW compounds, a small trapping column filled with absorbent must be used before thermal desorption of the collected samples onto chromatographic column(packed with Porapak Q) for separation. It has been proved that the characteristic of absorbent mainly influence the recoveries and the linear range of this method is from 0 05 ng to 5200 ng for pentane, methanol, ethanol and acetone.
文摘以壳寡糖为诱导物处理烟草植株,利用高效液相色谱 电化学(库仑电极)阵列检测技术检测不同处理时间植物体内内源激素的变化情况及其他小分子物质的差异显示。所用色谱柱为HypersilBDSC18柱(4.6mmi d ×200mm,5μm),八通道电化学阵列检测器(八个电极)的检测电势依次为-200,300,400,500,600,700,800,850mV。结果表明,茉莉酸(JA)和赤霉酸(GA)含量在用壳寡糖处理6h时达到高峰,吲哚乙酸(IAA)含量在处理8h时达到高峰。处理后烟草植株产生的其他一些未知的小分子物质尚有待定性和进一步考察其变化规律。
