The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied.Response surface methodology,in combination with central composite face-c...The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied.Response surface methodology,in combination with central composite face-centred design（RSM-CCF）,was used to optimise the operating parameters.The leaching temperature,sulphide ion concentration and solid concentration were chosen as the variables,and the response parameters were antimony and tin recovery,and the time required to achieve 90% Sb dissolution.It was confirmed that the leaching process was strongly dependent on the reaction temperature as well as the sulphide ion concentration without any significant dependence on the solid concentration.Furthermore,a mathematical model was constructed to characterise the leaching behaviour.The results from the model allow identification of the most favourable leaching conditions.The model was validated experimentally,and the results show that the model is reliable and accurate in predicting the leaching process.展开更多
Objectives:Due to health issues related to cholesterol and the emphasis on manufacture of low cholesterol food products,the research was undertaken for the extraction of cholesterol from cream powder using supercritic...Objectives:Due to health issues related to cholesterol and the emphasis on manufacture of low cholesterol food products,the research was undertaken for the extraction of cholesterol from cream powder using supercritical fluid extraction(SCFE)process.Materials and Methods:Face centered composite design(FCCD)was used to design the experiments with three independent variables viz.,extraction temperature(40˚C-75˚C),extraction pressure(100-250 bar)and dynamic time(2.5-3.5 h)taking two responses(cholesterol and fat content).The standardized flow rate and static time were 5 L/min(expanded CO_(2) gas)and 30 min,respectively.Response surface methodology was used for optimizing the process variables.Results:It was found that higher operating pressure,low extraction temperature and moderate amount of dynamic time facilitated the removal of cholesterol.The optimized process conditions of 75˚C,204 bar and 3.5 h dynamic time yielded 39%reduction in cholesterol content and 10.6%reduction in total fat content of the cream powder.Conclusions:Thus,a low cholesterol cream powder was developed with health benefits for people suffering from cardiovascular diseases.展开更多
Dehydrogenation of formic acid (FA) is considered to be an effective solution for efficient storage and transport of hydrogen. For decades, highly effective catalysts for this purpose have been widely investigated, bu...Dehydrogenation of formic acid (FA) is considered to be an effective solution for efficient storage and transport of hydrogen. For decades, highly effective catalysts for this purpose have been widely investigated, but numerous challenges remain. Herein, the Pd_(x)Au_(1−x) (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) alloys over the whole composition range were successfully prepared and used to catalyze FA hydrogen production efficiently near room temperature. Small PdAu nanoparticles (5–10 nm) were well-dispersed and supported on the activated carbon to form PdAu solid solution alloys via the eco-friendly slow synthesis methodology. The physicochemical properties of the PdAu alloys were comprehensively studied by utilizing various measurement methods, such as X-ray diffraction (XRD), N2 adsorption–desorption, high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), X-ray photoelectrons spectroscopy (XPS). Notably, owing to the strong metal-support interaction (SMSI) and electron transfer between active metal Au and Pd, the Pd0.5Au0.5 obtained exhibits a turnover frequency (TOF) value of up to 1648 h−1 (313 K, nPd+Au/nFA = 0.01, nHCOOH/nHCOONa = 1:3) with a high activity, selectivity, and reusability in the FA dehydrogenation.展开更多
文摘The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied.Response surface methodology,in combination with central composite face-centred design（RSM-CCF）,was used to optimise the operating parameters.The leaching temperature,sulphide ion concentration and solid concentration were chosen as the variables,and the response parameters were antimony and tin recovery,and the time required to achieve 90% Sb dissolution.It was confirmed that the leaching process was strongly dependent on the reaction temperature as well as the sulphide ion concentration without any significant dependence on the solid concentration.Furthermore,a mathematical model was constructed to characterise the leaching behaviour.The results from the model allow identification of the most favourable leaching conditions.The model was validated experimentally,and the results show that the model is reliable and accurate in predicting the leaching process.
文摘Objectives:Due to health issues related to cholesterol and the emphasis on manufacture of low cholesterol food products,the research was undertaken for the extraction of cholesterol from cream powder using supercritical fluid extraction(SCFE)process.Materials and Methods:Face centered composite design(FCCD)was used to design the experiments with three independent variables viz.,extraction temperature(40˚C-75˚C),extraction pressure(100-250 bar)and dynamic time(2.5-3.5 h)taking two responses(cholesterol and fat content).The standardized flow rate and static time were 5 L/min(expanded CO_(2) gas)and 30 min,respectively.Response surface methodology was used for optimizing the process variables.Results:It was found that higher operating pressure,low extraction temperature and moderate amount of dynamic time facilitated the removal of cholesterol.The optimized process conditions of 75˚C,204 bar and 3.5 h dynamic time yielded 39%reduction in cholesterol content and 10.6%reduction in total fat content of the cream powder.Conclusions:Thus,a low cholesterol cream powder was developed with health benefits for people suffering from cardiovascular diseases.
基金the National Natural Science Foundation of China(Grant Nos.52176131 and 51888103),the Natural Science Foundation of Shaanxi Province,China(Grant Nos.2021JLM-18,2020JC-04,and 2023KXJ-228)the National Science and Technology Major Project of China(No.J2019-III-0018-0062)Xi’an Jiaotong University Special Research Project for Basic Research Business Expenses(No.xzy022022043).
文摘Dehydrogenation of formic acid (FA) is considered to be an effective solution for efficient storage and transport of hydrogen. For decades, highly effective catalysts for this purpose have been widely investigated, but numerous challenges remain. Herein, the Pd_(x)Au_(1−x) (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) alloys over the whole composition range were successfully prepared and used to catalyze FA hydrogen production efficiently near room temperature. Small PdAu nanoparticles (5–10 nm) were well-dispersed and supported on the activated carbon to form PdAu solid solution alloys via the eco-friendly slow synthesis methodology. The physicochemical properties of the PdAu alloys were comprehensively studied by utilizing various measurement methods, such as X-ray diffraction (XRD), N2 adsorption–desorption, high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), X-ray photoelectrons spectroscopy (XPS). Notably, owing to the strong metal-support interaction (SMSI) and electron transfer between active metal Au and Pd, the Pd0.5Au0.5 obtained exhibits a turnover frequency (TOF) value of up to 1648 h−1 (313 K, nPd+Au/nFA = 0.01, nHCOOH/nHCOONa = 1:3) with a high activity, selectivity, and reusability in the FA dehydrogenation.
