Fluorine is in the dynamic balance of two geochemical processes, enrichment and leaching, reflecting the adsorption and desorption of fluoride by clay minerals, respectively. The two geochemical processes of fluorine ...Fluorine is in the dynamic balance of two geochemical processes, enrichment and leaching, reflecting the adsorption and desorption of fluoride by clay minerals, respectively. The two geochemical processes of fluorine in soil are influenced by factors including geochemical characteristics of soil and clay minerals, pH and sanity of soil solutions, climate, grazing and agriculture activities. Main factors controlling enrichment and leaching process of fluorine in soil can be found with interaction consideration.展开更多
Methiopyrisulfuron is a novel sulfonylurea herbicide with good activity for annual broadleaf and gramineal weeds control. Present study was to investigate the effects of organic amendments （including peat （PE）, sew...Methiopyrisulfuron is a novel sulfonylurea herbicide with good activity for annual broadleaf and gramineal weeds control. Present study was to investigate the effects of organic amendments （including peat （PE）, sewage sludge （SS）, and humic acid （HA）） on adsorption, desorption and leaching of methiopyrisulfuron in soils. The batch equilibration technique was applied for adsorption-desorption experiments and the leaching was tested through soil column simulated experiments under laboratory conditions. The Freundlich model may well describe adsorption-desorption of methiopyrisulfuron on organic amendments, the natural soil, and amended soils. Organic amendments could not only greatly increase the adsorption capacity of methiopyrisulfuron, but also significantly enhance the hysteresis of desorption of methiopyrisulfuron. The correlations between Kf_ads and organic matter content of amended soils were significant, and the correlations between H and soil organic matter in amended soils with PE, SS, and HA were significant too. The results of soil column experiments indicated that organic amendments greatly decreased leaching of methiopyrisulfuron. This study suggested that PE, SS, and HA could greatly influence environmental behavior of methiopyrisulfuron in soils. Use of organic amendments might be an effective management practice for controlling potential pollution of methiopyrisulfuron to environment.展开更多
The recovery of Ge from lignite by microorganism includes two stages: (1) thebreaking-down of Ge complex of humus in lignite into simple compounds assisted by microorganism;(2) the desorption of Ge compounds from the ...The recovery of Ge from lignite by microorganism includes two stages: (1) thebreaking-down of Ge complex of humus in lignite into simple compounds assisted by microorganism;(2) the desorption of Ge compounds from the lignite. The recovery rate of Ge has been enhanced by 14percent since the discovery of adsorption and desorption of Ge from coal. The effects of pH,leaching agents, and coal size on the recovery of Ge were experimentally investigated, and theoptimized process parameters were obtained. The reaction heat of Ge adsorption and desorption inlignite was determined. It is about 23-53 kJ/mol, which reveals that the adsorption belongs tophysical process. The recovery rate of Ge from lignite with direct microorganism leaching can reachabout 85 percent, which is higher than that of 60 percent reported elsewhere. A potential processfor leaching Ge in lignite was suggested.展开更多
Biochar is produced from the pyrolysis of carbon-rich plant- and animal-residues under low oxygen and high temperature conditions and has been increasingly used for its positive role in soil compartmentalization throu...Biochar is produced from the pyrolysis of carbon-rich plant- and animal-residues under low oxygen and high temperature conditions and has been increasingly used for its positive role in soil compartmentalization through activities such as carbon sequestration and improving soil quality. Biochar is also considered a unique adsorbent due to its high specific surface area and highly carbonaceous nature. Therefore, soil amendments with small amounts of biochar could result in higher adsorption and, consequently, decrease the bioavailability of contaminants to microbial communities, plants, earthworms, and other organisms in the soil. However, the mechanisms affecting the environmental fate and behavior of organic contaminants, especially pesticides in biochar-amended soil, are not well understood. The purpose of this work is to review the role of biochar in primary processes, such as adsorption–desorption and leaching of pesticides. Biochar has demonstrable effects on the fate and effects of pesticides and has been shown to affect the degradation and bioavailability of pesticides for living organisms. Moreover, some key aspects of agricultural and environmental applications of biochar are highlighted.展开更多
基金supported by the Key Project of International Cooperation of the Ministry of Science and Technology of China(2010DFB30530)Social Development Project of Guizhou Province,China(SZ[2009]3045)Science and Technology Foundation of Guizhou Province,China(J[2008]2312)
文摘Fluorine is in the dynamic balance of two geochemical processes, enrichment and leaching, reflecting the adsorption and desorption of fluoride by clay minerals, respectively. The two geochemical processes of fluorine in soil are influenced by factors including geochemical characteristics of soil and clay minerals, pH and sanity of soil solutions, climate, grazing and agriculture activities. Main factors controlling enrichment and leaching process of fluorine in soil can be found with interaction consideration.
文摘Methiopyrisulfuron is a novel sulfonylurea herbicide with good activity for annual broadleaf and gramineal weeds control. Present study was to investigate the effects of organic amendments （including peat （PE）, sewage sludge （SS）, and humic acid （HA）） on adsorption, desorption and leaching of methiopyrisulfuron in soils. The batch equilibration technique was applied for adsorption-desorption experiments and the leaching was tested through soil column simulated experiments under laboratory conditions. The Freundlich model may well describe adsorption-desorption of methiopyrisulfuron on organic amendments, the natural soil, and amended soils. Organic amendments could not only greatly increase the adsorption capacity of methiopyrisulfuron, but also significantly enhance the hysteresis of desorption of methiopyrisulfuron. The correlations between Kf_ads and organic matter content of amended soils were significant, and the correlations between H and soil organic matter in amended soils with PE, SS, and HA were significant too. The results of soil column experiments indicated that organic amendments greatly decreased leaching of methiopyrisulfuron. This study suggested that PE, SS, and HA could greatly influence environmental behavior of methiopyrisulfuron in soils. Use of organic amendments might be an effective management practice for controlling potential pollution of methiopyrisulfuron to environment.
基金This work is financially supported by the Yunnan Science Fund (No. 1999E0029M).
文摘The recovery of Ge from lignite by microorganism includes two stages: (1) thebreaking-down of Ge complex of humus in lignite into simple compounds assisted by microorganism;(2) the desorption of Ge compounds from the lignite. The recovery rate of Ge has been enhanced by 14percent since the discovery of adsorption and desorption of Ge from coal. The effects of pH,leaching agents, and coal size on the recovery of Ge were experimentally investigated, and theoptimized process parameters were obtained. The reaction heat of Ge adsorption and desorption inlignite was determined. It is about 23-53 kJ/mol, which reveals that the adsorption belongs tophysical process. The recovery rate of Ge from lignite with direct microorganism leaching can reachabout 85 percent, which is higher than that of 60 percent reported elsewhere. A potential processfor leaching Ge in lignite was suggested.
基金supported by the National High Technology R&D Program of China (No. 2013AA065202)Zhejiang Provincial Natural Science Foundation (No. LZ13D010001)+1 种基金the National Natural Science Foundation of China (Nos. 41271489 and 21477112)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120101110073)
文摘Biochar is produced from the pyrolysis of carbon-rich plant- and animal-residues under low oxygen and high temperature conditions and has been increasingly used for its positive role in soil compartmentalization through activities such as carbon sequestration and improving soil quality. Biochar is also considered a unique adsorbent due to its high specific surface area and highly carbonaceous nature. Therefore, soil amendments with small amounts of biochar could result in higher adsorption and, consequently, decrease the bioavailability of contaminants to microbial communities, plants, earthworms, and other organisms in the soil. However, the mechanisms affecting the environmental fate and behavior of organic contaminants, especially pesticides in biochar-amended soil, are not well understood. The purpose of this work is to review the role of biochar in primary processes, such as adsorption–desorption and leaching of pesticides. Biochar has demonstrable effects on the fate and effects of pesticides and has been shown to affect the degradation and bioavailability of pesticides for living organisms. Moreover, some key aspects of agricultural and environmental applications of biochar are highlighted.
