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91.
Electrochemical and spectroscopic characteristics of dissolved organic matter in a forest soil profile 总被引:2,自引:0,他引:2
Dissolved organic matter (DOM) represents one of the most mobile and reactive organic compounds in ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Electrochemical methods were first employed to evaluate DOM redox properties, and spectroscopic approaches were utilized to obtain information concerning its composition and structure. DOM was extracted from a forest soil profile with five horizons. Differential pulse voltammetry indicated that there were more redox-active moieties in the DOM from upper horizons than in that from lower horizons. Cyclic voltammetry further showed that these moieties were reversible in electron transfer. Chronoamperometry was employed to quantify the electron transfer capacity of DOM, including electron acceptor capacity and electron donor capacity, both of which decreased sharply with increasing depth. FT-IR, UV-Vis and fluorescence spectra results suggested that DOM from the upper horizons was enriched with aromatic and humic structures while that from the lower horizons was rich in aliphatic carbon, which supported the findings obtained by electrochemical approaches. Electrochemical approaches combined with spectroscopic methods were applied to evaluate the characteristics of DOM extracted along a forest soil profile. The electrochemical properties of DOM, which can be rapidly and simply obtained, provide insight into the migration and transformation of DOM along a soil profile and will aid in better understanding of the biogeochemical role of DOM in natural environments. 相似文献
92.
对上海市不同区域疏浚泥的颗粒粒径、化学成分、毒性、养分等理化性质进行测定,继而对其资源化可利用性进行了分析。结果表明,上海市疏浚泥可定性为粘质粉土和粉质粘土;3个采样区的样品均没有达到清洁疏浚泥的标准。内河航道疏浚泥养分充足但镉污染稍显严重,采取重金属预防措施后适宜作为农作地和湿地矿山修复用地;黄浦江码头前沿和长江码头前沿疏浚泥有机质严重不足,仅适于在绿地、绿化带、防护林等处使用;3处疏浚泥均可制陶粒和制砖,亦可用于围内吹填工程,但需事先对疏浚泥里的重金属成分进行固化。 相似文献
93.
通过对龙江县海洋林场生态公益林不同林分类型理化性质测定,得出物理指标中的总孔隙度较大,化学指标的P极度缺乏,K较缺乏,N中等水平的结论,并探讨生态公益林对土壤理化性质、蓄水能力的影响。 相似文献
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95.
酿酒酵母吸附Pb(Ⅱ)的表面特性研究 总被引:1,自引:1,他引:0
为深入探讨酿酒酵母吸附Pb(Ⅱ)的微观作用机制,本文利用表面显微分析技术(SEM-EDS、TEM-EDS、AFM)研究了酿酒酵母细胞吸附重金属离子Pb(Ⅱ)前后的细胞表面变化.研究结果表明,酿酒酵母细胞与Pb(Ⅱ)作用后,细胞表面除吸附Pb(Ⅱ)外,同时产生大量更高浓度的含Pb(Ⅱ)沉淀,导致Pb(Ⅱ)从溶液中被去除.酵母与Pb(Ⅱ)反应前,酵母细胞表面可检测到的主要元素包括C、O、N、P、S、K、Mg;酵母与Pb(Ⅱ)作用后,细胞表面始终保持C、O、P吸收峰,而N、K、Mg、S吸收峰随反应条件不同而减弱、消失或增强.P作为细胞表面组分可能与Pb(Ⅱ)结合.酵母与Pb(Ⅱ)作用过程中,重金属离子促进酵母细胞释放细胞内含物.原子力显微镜(AFM)证实,云母片表面对酵母吸附Pb(Ⅱ)后细胞的铺展变形作用明显增大. 相似文献
96.
97.
The Cu2+-loaded montmorillonite clays (MMT-Cu) may be a good material for the adsorbed and eliminated pathogenic bacteria from aqueous solution. 相似文献
98.
Surfactant-enhanced remediation (SER) is an effective method for the removal of volatile organic compounds (VOCs) from contaminated soils and groundwater. To reuse the surfactant the VOCs must be separated from the surfactant solutions. The water solubility of VOCs can be enhanced using reversible surfactants with a redox-acive group, (ferrocenylmethyl)dodecyldimethylammonium bromide (Fcl2) and (ferrocenylmethyl)tetradecanedimethylammonium bromide (Fcl4), above and below their critical micelle concentrations (CMC) under reducing (I+) and oxidative (I2+) conditions. The CMC values of Fcl2 and Fcl4 in I+ are 0.94 and 0.56 mmol/L and the solubilization of toluene by Fcl2 and Fcl4 in I+ for toluene is higher than the solubilization achieved with sodium dodecyl sulfate, cetyltrimethylammonium bromide and Trition X-114. The solubilization capacity of the ferrocenyl surfactants for each tested VOCs ranked as follows: ethylbenzene > toluene > benzene. The solubilities of VOCs by reversible surfactant in I+ were 30% higher than those in I2+ at comparable surfactant concentrations. The effects of Fcl4 concentrations on VOCs removal efficiency were as follows: benzene > toluene > ethylbenzene. However, an improved removal efficiency was achieved at low ferrocenyl surfactant concentrations. Furthermore, the reversible surfactant could be recycled through chemical approaches to remove organic pollutants, which could significantly reduce the operating costs of SER technology. 相似文献
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100.