Natural minerals receive growing attention as inexpensive, green, and efficient catalysts for degradation of organic pollutants. Mechanical activation of natural chalcopyrite was conducted for improving the catalytic ...Natural minerals receive growing attention as inexpensive, green, and efficient catalysts for degradation of organic pollutants. Mechanical activation of natural chalcopyrite was conducted for improving the catalytic performance.Tetracycline degradation was evaluated in the presence of hydrogen peroxide and mechanically activated chalcopyrite.Tetracycline degradation at 100 min is 55.52%(Chp10), 68.97%(Chp30), 77.79%(Chp60), and 86.43%(Chp120),respectively, and the rate constant of pseudo-first-order kinetics is 0.0079, 0.0109, 0.0137 and 0.0192 min^(-1), respectively.Chalcopyrite samples were examined by multiple characterizations. Mechanical activation of natural chalcopyrite induces the decline of particle size and slight increase of surface area, smaller grain size, lattice strain, and partial sulfur oxidation. The relationship between catalytic activity and property change manifests that the improved catalytic ability is mainly ascribed to the increase of surface area and surface oxidation induced by mechanical activation. This work provides novel insights into the improvement of catalytic performance of natural minerals by mechanical activation.展开更多
The North Tibet plateau is the world highest plateau with a unique alpine grassland and water environment. To obtain a better understanding of the correct supply of Molybdenum（Mo） to livestock in north Tibet,we inve...The North Tibet plateau is the world highest plateau with a unique alpine grassland and water environment. To obtain a better understanding of the correct supply of Molybdenum（Mo） to livestock in north Tibet,we investigated the content and geographical variation of Mo in different families of pasture plants（n=1017） and water（n=40）,then discuss the Cuprum（Cu）：Mo ratio in different plant families,and calculate the total Mo intake of the yak in north Tibet. The average Mo concentration in five families preferred for grazing are： Compositae（2.71 μg g^（-1））,Leguminosae（2.70 μg g^（-1））,Gramineae（2.48 μg g^（-1））,Cyperaceae（1.63 μg g^（-1））,and Rosaceae（1.51 μg g^（-1））. There was a strong geographical variation in Mo concentration（p 0.001）. The mean value of Mo in north Tibet surface water from 15 sites is 0.89 μg L^（-1）. The Mo ingestion by yak through these plants and water in north Tibet is about 9586 μg day^（-1） which means the toxicity of Mo does not exist in the average daily diet. However,the large geographical variation found may cause some toxicity of Mo in the average daily intake of north Tibet pasture plants in some areas. The Cu：Mo ratio of 2：60 is considered the limit for risk of Mo hyperactivity,while extremely high Cu：Mo ratios may lead to chronic copper poisoning. Our survey of plant samples found 43.29% below and 29.3% above the limiting Cu：Mo ratio of 60 indicating some risk to north Tibet livestock.展开更多
基金Project(2020YFC1908802) supported by the National Key Research and Development Project of China。
文摘Natural minerals receive growing attention as inexpensive, green, and efficient catalysts for degradation of organic pollutants. Mechanical activation of natural chalcopyrite was conducted for improving the catalytic performance.Tetracycline degradation was evaluated in the presence of hydrogen peroxide and mechanically activated chalcopyrite.Tetracycline degradation at 100 min is 55.52%(Chp10), 68.97%(Chp30), 77.79%(Chp60), and 86.43%(Chp120),respectively, and the rate constant of pseudo-first-order kinetics is 0.0079, 0.0109, 0.0137 and 0.0192 min^(-1), respectively.Chalcopyrite samples were examined by multiple characterizations. Mechanical activation of natural chalcopyrite induces the decline of particle size and slight increase of surface area, smaller grain size, lattice strain, and partial sulfur oxidation. The relationship between catalytic activity and property change manifests that the improved catalytic ability is mainly ascribed to the increase of surface area and surface oxidation induced by mechanical activation. This work provides novel insights into the improvement of catalytic performance of natural minerals by mechanical activation.
基金Key Science and Technology Research Program of Tibet(ZDZX2017000122,XZ201801NA02)Natural Science Foundation of Tibet(2016ZR-15-76)Key Science and Technology Research Program of Tibet(Z2016C01G01)
文摘The North Tibet plateau is the world highest plateau with a unique alpine grassland and water environment. To obtain a better understanding of the correct supply of Molybdenum（Mo） to livestock in north Tibet,we investigated the content and geographical variation of Mo in different families of pasture plants（n=1017） and water（n=40）,then discuss the Cuprum（Cu）：Mo ratio in different plant families,and calculate the total Mo intake of the yak in north Tibet. The average Mo concentration in five families preferred for grazing are： Compositae（2.71 μg g^（-1））,Leguminosae（2.70 μg g^（-1））,Gramineae（2.48 μg g^（-1））,Cyperaceae（1.63 μg g^（-1））,and Rosaceae（1.51 μg g^（-1））. There was a strong geographical variation in Mo concentration（p 0.001）. The mean value of Mo in north Tibet surface water from 15 sites is 0.89 μg L^（-1）. The Mo ingestion by yak through these plants and water in north Tibet is about 9586 μg day^（-1） which means the toxicity of Mo does not exist in the average daily diet. However,the large geographical variation found may cause some toxicity of Mo in the average daily intake of north Tibet pasture plants in some areas. The Cu：Mo ratio of 2：60 is considered the limit for risk of Mo hyperactivity,while extremely high Cu：Mo ratios may lead to chronic copper poisoning. Our survey of plant samples found 43.29% below and 29.3% above the limiting Cu：Mo ratio of 60 indicating some risk to north Tibet livestock.
