采用KCl作为添加剂,根据差示扫描量热仪（DSC）测得的DSC曲线,对非等温动力学微分方程采用Achar-Brindley-Sharp-Wendworth法拟合实验数据,逻辑选择确定KCl-Na OH混合碱熔分解锆英砂的最可几微分机制函数及动力学参数,并对碱熔分解过程...采用KCl作为添加剂,根据差示扫描量热仪（DSC）测得的DSC曲线,对非等温动力学微分方程采用Achar-Brindley-Sharp-Wendworth法拟合实验数据,逻辑选择确定KCl-Na OH混合碱熔分解锆英砂的最可几微分机制函数及动力学参数,并对碱熔分解过程进行动力学分析。研究结果表明：KCl-Na OH混合碱熔分解锆英砂在分解深度为0.01~0.09范围内时,最可几微分机制函数为f（a）=（1-a）2,表观活化能和指前因子分别为199.7 k J·mol-1和1×1010.39s-1。当分解深度为0.29~0.60时,最可几微分机制函数转变为f（a）=3/2[（1-a）-1/3-1]-1,表观活化能和指前因子转变为139.25 k J·mol-1和1×108.52s-1。KCl的加入改变了碱熔分解反应的表观活化能和指前因子,使得碱熔分解反应表观活化能降低,碱熔体系的反应速率增大。KCl-Na OH混合碱熔分解锆英砂反应在609~665℃时,为化学反应控速。随着碱熔分解反应的继续进行,当反应温度为730~811℃时,锆英砂表面不断被产物层包裹,反应机制转变为三维扩散,球形对称,扩散控制过程。展开更多
Soil dissolved organic matter （DOM） consists of many organic compounds and plays an important role in contaminant transport in the ecosystem. However, the effects of different extraction conditions on contents of di...Soil dissolved organic matter （DOM） consists of many organic compounds and plays an important role in contaminant transport in the ecosystem. However, the effects of different extraction conditions on contents of different DOM components are poorly understood. We extracted DOM from three soils using different extraction times, solid to liquid ratios （SLR）, and extraction solution （KC1） concentrations, and evaluated the extractions using three-dimensional excitation-emission matrix （EEM） fluorescence spectroscopy. The sum of the contents of the main DOM components （protein-, fulvic-, and humic-like compounds） increased by 0.6-3.5, 2.5-3.9, and 0.11 0.37 times （P 〈 0.05） when SLR decreased from 1：2 to 1：10, the extraction solution concentration increased from 0.01 to 1.5 mol L-1, and extraction time increased from 10 to 300 rain, respectively. The three-dimensional EEM fluorescence spectroscopy is a useful tool to characterize the components of DOM and evaluate DOM extraction in soils.展开更多
Gypsum crystallization along with the simultaneous regeneration of KCl was investigated by the reaction of CaCl2 solution with K2SO4.Well developed sheet structure gypsum crystals were produced when K2SO4 solution was...Gypsum crystallization along with the simultaneous regeneration of KCl was investigated by the reaction of CaCl2 solution with K2SO4.Well developed sheet structure gypsum crystals were produced when K2SO4 solution was added into the CaCl2 solution by slow titration or in multiple stages over 2-8 h followed by 2 h equilibration.In order to regenerate KCl solution as concentrated as possible,K2SO4 solid was added into the given CaCl2 solution instead of K2SO4 solution,obtaining gypsum crystals with almost the same quality by multistage addition with[SO4 2-]/[Ca 2+]molar ratio no larger than 0.8.However,impurity of K2SO4·CaSO4·H2O was detected by XRD and was further confirmed by SEM-EDS in the produced crystals when the[SO4 2-]/[Ca 2+] ratio increased to 1.1.It is proved that appearance of the double sulfate is attributed to the relatively high concentration of K2SO4.So,it is essential to properly control the[SO4 2-]/[Ca 2+]ratio and make sure[Ca 2+ ]in excess to suppress the solubility of CaSO4 even at the expense of low calcium removal rate.展开更多
基金supported by the National Natural Science Foundation of China(No.31371165 and 31571179)the Natural Science Foundation of Fujian Province+2 种基金China(No.2015J01313)the Youth Research Project of Fujian Provincial Department of HealthChina(No.2013-1-21)
文摘采用KCl作为添加剂,根据差示扫描量热仪（DSC）测得的DSC曲线,对非等温动力学微分方程采用Achar-Brindley-Sharp-Wendworth法拟合实验数据,逻辑选择确定KCl-Na OH混合碱熔分解锆英砂的最可几微分机制函数及动力学参数,并对碱熔分解过程进行动力学分析。研究结果表明：KCl-Na OH混合碱熔分解锆英砂在分解深度为0.01~0.09范围内时,最可几微分机制函数为f（a）=（1-a）2,表观活化能和指前因子分别为199.7 k J·mol-1和1×1010.39s-1。当分解深度为0.29~0.60时,最可几微分机制函数转变为f（a）=3/2[（1-a）-1/3-1]-1,表观活化能和指前因子转变为139.25 k J·mol-1和1×108.52s-1。KCl的加入改变了碱熔分解反应的表观活化能和指前因子,使得碱熔分解反应表观活化能降低,碱熔体系的反应速率增大。KCl-Na OH混合碱熔分解锆英砂反应在609~665℃时,为化学反应控速。随着碱熔分解反应的继续进行,当反应温度为730~811℃时,锆英砂表面不断被产物层包裹,反应机制转变为三维扩散,球形对称,扩散控制过程。
基金the financial support of the Special Environmental Research Fund for Public Welfare of the State Environmental Protection Administration of China (No.201309035)the Natural Science Foundation of China (No.51408587)
文摘Soil dissolved organic matter （DOM） consists of many organic compounds and plays an important role in contaminant transport in the ecosystem. However, the effects of different extraction conditions on contents of different DOM components are poorly understood. We extracted DOM from three soils using different extraction times, solid to liquid ratios （SLR）, and extraction solution （KC1） concentrations, and evaluated the extractions using three-dimensional excitation-emission matrix （EEM） fluorescence spectroscopy. The sum of the contents of the main DOM components （protein-, fulvic-, and humic-like compounds） increased by 0.6-3.5, 2.5-3.9, and 0.11 0.37 times （P 〈 0.05） when SLR decreased from 1：2 to 1：10, the extraction solution concentration increased from 0.01 to 1.5 mol L-1, and extraction time increased from 10 to 300 rain, respectively. The three-dimensional EEM fluorescence spectroscopy is a useful tool to characterize the components of DOM and evaluate DOM extraction in soils.
基金Project(50974018)supported by the National Natural Science Foundation of ChinaProject(108007)supported by Key Project of the Ministry of Education of China
文摘Gypsum crystallization along with the simultaneous regeneration of KCl was investigated by the reaction of CaCl2 solution with K2SO4.Well developed sheet structure gypsum crystals were produced when K2SO4 solution was added into the CaCl2 solution by slow titration or in multiple stages over 2-8 h followed by 2 h equilibration.In order to regenerate KCl solution as concentrated as possible,K2SO4 solid was added into the given CaCl2 solution instead of K2SO4 solution,obtaining gypsum crystals with almost the same quality by multistage addition with[SO4 2-]/[Ca 2+]molar ratio no larger than 0.8.However,impurity of K2SO4·CaSO4·H2O was detected by XRD and was further confirmed by SEM-EDS in the produced crystals when the[SO4 2-]/[Ca 2+] ratio increased to 1.1.It is proved that appearance of the double sulfate is attributed to the relatively high concentration of K2SO4.So,it is essential to properly control the[SO4 2-]/[Ca 2+]ratio and make sure[Ca 2+ ]in excess to suppress the solubility of CaSO4 even at the expense of low calcium removal rate.
