The particle size of sediment is one of the main factors that influence the phosphorus physical adsorption on sediment. In order to eliminate the effect of other components of sediment on the phosphorus physical adsor...The particle size of sediment is one of the main factors that influence the phosphorus physical adsorption on sediment. In order to eliminate the effect of other components of sediment on the phosphorus physical adsorption, the sediment mineral matrices were obtained by removing inorganic matter, metal oxides, and organic matter from natural sediments, which were collected from the Nantong reach of the Yangtze River. The results show that an exponential relationship exists between the median particle size （Ds0） and specific surface area （Sg） of the sediment mineral matrices, and the fine sediment mineral matrix sample has a larger specific surface area and pore volume than the coarse sediment particles. The kinetic equations were used to describe the phosphorus adsorption process of the sediment mineral matrices, including the Elovich equation, quasi-first-order adsorption kinetic equation, and quasi-second-order adsorption kinetic equation. The results show that the quasi-second-order adsorption kinetic equation has the best fitting effect. Using the mass conservation and Langmuir adsorption kinetic equations, a formula was deduced to calculate the equilibrium adsorption capacity of the sediment mineral matrices. The results of this study show that the phosphorus adsorption capacity decreases with the increase of Ds0, indicating that the specific surface area and pore volume are the main factors in determining the phosphorus adsorption capacity of the sediment mineral matrices. This study will help understand the important role of sediment in the transformation of phosphorus in aquatic environments.展开更多
This paper investigated the influence of steam explosion pretreatment with or without acid as the catalyst on the chemical composition and sugar contents of corn stalks.The fiber characteristics of the pretreated corn...This paper investigated the influence of steam explosion pretreatment with or without acid as the catalyst on the chemical composition and sugar contents of corn stalks.The fiber characteristics of the pretreated corn stalks were analyzed with a scanning electron microscope,a FS-300 automatic fiber analyzer and a fully automatic surface and pore analyzer.The results showed that the steam explosion pretreatment did not change the cellulose content of the corn stalks.However,hemicellulose was degraded and a portion of lignin was solubilized in the steam explosion pretreatment process.When acid was added in the steam explosion process,the fiber surface and cell wall structure of corn stalks were damaged,the specific surface area and pore size increased,and fiber length decreased,all of which were beneficial to subsequent enzymatic hydrolysis with cellulase.However,content of polysaccharides decreased after acid steam explosion pretreatment.展开更多
基金supported by the National Natural Science Foundation of China (Grants No. 51179055,51239003, and 51125034)the Special Fund of State Key Laboratory of China (Grant No. 2010585512)
文摘The particle size of sediment is one of the main factors that influence the phosphorus physical adsorption on sediment. In order to eliminate the effect of other components of sediment on the phosphorus physical adsorption, the sediment mineral matrices were obtained by removing inorganic matter, metal oxides, and organic matter from natural sediments, which were collected from the Nantong reach of the Yangtze River. The results show that an exponential relationship exists between the median particle size （Ds0） and specific surface area （Sg） of the sediment mineral matrices, and the fine sediment mineral matrix sample has a larger specific surface area and pore volume than the coarse sediment particles. The kinetic equations were used to describe the phosphorus adsorption process of the sediment mineral matrices, including the Elovich equation, quasi-first-order adsorption kinetic equation, and quasi-second-order adsorption kinetic equation. The results show that the quasi-second-order adsorption kinetic equation has the best fitting effect. Using the mass conservation and Langmuir adsorption kinetic equations, a formula was deduced to calculate the equilibrium adsorption capacity of the sediment mineral matrices. The results of this study show that the phosphorus adsorption capacity decreases with the increase of Ds0, indicating that the specific surface area and pore volume are the main factors in determining the phosphorus adsorption capacity of the sediment mineral matrices. This study will help understand the important role of sediment in the transformation of phosphorus in aquatic environments.
基金support from the Special Support Plan for High-Level Talent Cultivation of Guangdong Province (No.2014TQ01N603)Key Laboratory of Pulp and Paper Science&Technology of Ministry of Education of China (No.KF201508)Guangdong province science&technology plan projects (No.2015B020241001).
文摘This paper investigated the influence of steam explosion pretreatment with or without acid as the catalyst on the chemical composition and sugar contents of corn stalks.The fiber characteristics of the pretreated corn stalks were analyzed with a scanning electron microscope,a FS-300 automatic fiber analyzer and a fully automatic surface and pore analyzer.The results showed that the steam explosion pretreatment did not change the cellulose content of the corn stalks.However,hemicellulose was degraded and a portion of lignin was solubilized in the steam explosion pretreatment process.When acid was added in the steam explosion process,the fiber surface and cell wall structure of corn stalks were damaged,the specific surface area and pore size increased,and fiber length decreased,all of which were beneficial to subsequent enzymatic hydrolysis with cellulase.However,content of polysaccharides decreased after acid steam explosion pretreatment.
