The reaction between chlorite and thiourea could display batch oligooscillation and CSTR oscillation of pH.Batch pH peak has the same character with pH oscillation in a CSTR.The oxidation of thiourea produced intermed...The reaction between chlorite and thiourea could display batch oligooscillation and CSTR oscillation of pH.Batch pH peak has the same character with pH oscillation in a CSTR.The oxidation of thiourea produced intermediates such as HOSC(NH)NH2,HO2SC(NH)NH2,HO3S(NH)NH2 and bisulfite.The valence change of sulfur has close relation with pH dynamics.Through the mechanistic analysis,a general model of sulfur(－ II) oxidation,which consists of negative hydrogen ion feedback(S(－ II) to S(0)),a transition process of S(0) to S(IV) and positive proton feedback from S(IV) to S(VI),could simulate batch oligooscillation and CSTR oscillation.This result is setting up a new channel to uncover the reaction mechanism and simulate the nonlinear phenomena in the reactions between chlorite and Sulfur(－ II).展开更多
In recent years,nonlinear chemical reactions,mechanisms and complex phenomena inunhalogen aqueous reaction systems have attracted much attention.Jesen oscillator andsulfide-sulfite-oxygen-methylene blue oscillator aro...In recent years,nonlinear chemical reactions,mechanisms and complex phenomena inunhalogen aqueous reaction systems have attracted much attention.Jesen oscillator andsulfide-sulfite-oxygen-methylene blue oscillator aroused great interest in nonlinear reactionsystems without halogen.Later,hydrogen peroxide-thiocyanate-copper sulfate reaction wasdesigned to display bistability and oscillation.According to the experimental results at展开更多
Two kinds of different mechanistic oscillations can be displayed in the H_2O_2-KSCN-CuSO_4-NaOH system. One discovered by this study is the pH oscillation in a continuous flow stirred tank reactor(CSTR) resulting from...Two kinds of different mechanistic oscillations can be displayed in the H_2O_2-KSCN-CuSO_4-NaOH system. One discovered by this study is the pH oscillation in a continuous flow stirred tank reactor(CSTR) resulting from the oxidation of KSCN. The other is the oscillation of H_2O_2 decomposition in both CSTR and batch reactors(reported by Orbáin in 1986). Under appropriate experimental conditions, the system exhibits a birhythmicity in a CSTR. Two different pH oscillations are reported here. The pH oscillations which accompany the decomposition of H_2O_2 exist in the batch reactor and the CSTR at a high flowrate, but the pH oscillations in a CSTR at a low flowrate originates from proton positive and negative feedback in the oxidation of KSCN. The oscillation of non-catalyzed oxidation of KSCN by hydrogen peroxide in a CSTR can be found. Also we have observed whether Cu^(2+) exists or not in the batch system, the pH increases to near neutral ultimately after pH drops twice.展开更多
采用电位计法比较了活性纳米碳酸钙pH值测试过程中过滤、暴露时间、乙醇浸润量、温度、回旋振荡时间等对活性纳米碳酸钙pH值测试结果的影响。较佳的测试条件为:取(10±0.01)g活性纳米碳酸钙经乙醇浸润,加入100 m L无CO_2的水,在(50&...采用电位计法比较了活性纳米碳酸钙pH值测试过程中过滤、暴露时间、乙醇浸润量、温度、回旋振荡时间等对活性纳米碳酸钙pH值测试结果的影响。较佳的测试条件为:取(10±0.01)g活性纳米碳酸钙经乙醇浸润,加入100 m L无CO_2的水,在(50±1)℃下回旋振荡30 min,待悬浮液冷却至(25±1)℃,过滤,测试滤液的pH值。展开更多
为优化pH值的测试影响因素,采用GB/T7573-2009和JIS L 1096-2010两种方法,选择试样大小、振荡时间和萃取液静置时间为自变量,pH值为响应面值,通过单因素试验、Box-Benhnken中心组合试验和响应面分析法,指明了影响pH值测试的显著性因素,...为优化pH值的测试影响因素,采用GB/T7573-2009和JIS L 1096-2010两种方法,选择试样大小、振荡时间和萃取液静置时间为自变量,pH值为响应面值,通过单因素试验、Box-Benhnken中心组合试验和响应面分析法,指明了影响pH值测试的显著性因素,并探讨了3个因素交互作用对pH值测试的影响,得到二次多元回归方程,确定了pH值的较优测试条件:试样大小0.5mm×0.5mm,振荡时间1h,萃取液静置时间1h。GB/T7573-2009的测试结果与JIS L 1096-2010的测试结果对比表明,GB/T7573-2009的测试结果一般稍大于JIS L1096-2010的结果。展开更多
文摘The reaction between chlorite and thiourea could display batch oligooscillation and CSTR oscillation of pH.Batch pH peak has the same character with pH oscillation in a CSTR.The oxidation of thiourea produced intermediates such as HOSC(NH)NH2,HO2SC(NH)NH2,HO3S(NH)NH2 and bisulfite.The valence change of sulfur has close relation with pH dynamics.Through the mechanistic analysis,a general model of sulfur(－ II) oxidation,which consists of negative hydrogen ion feedback(S(－ II) to S(0)),a transition process of S(0) to S(IV) and positive proton feedback from S(IV) to S(VI),could simulate batch oligooscillation and CSTR oscillation.This result is setting up a new channel to uncover the reaction mechanism and simulate the nonlinear phenomena in the reactions between chlorite and Sulfur(－ II).
基金supported by the National Natural Science Foundation of China.
文摘In recent years,nonlinear chemical reactions,mechanisms and complex phenomena inunhalogen aqueous reaction systems have attracted much attention.Jesen oscillator andsulfide-sulfite-oxygen-methylene blue oscillator aroused great interest in nonlinear reactionsystems without halogen.Later,hydrogen peroxide-thiocyanate-copper sulfate reaction wasdesigned to display bistability and oscillation.According to the experimental results at
基金Supported by NSFC(29573109) and Research fund of CUMT.
文摘Two kinds of different mechanistic oscillations can be displayed in the H_2O_2-KSCN-CuSO_4-NaOH system. One discovered by this study is the pH oscillation in a continuous flow stirred tank reactor(CSTR) resulting from the oxidation of KSCN. The other is the oscillation of H_2O_2 decomposition in both CSTR and batch reactors(reported by Orbáin in 1986). Under appropriate experimental conditions, the system exhibits a birhythmicity in a CSTR. Two different pH oscillations are reported here. The pH oscillations which accompany the decomposition of H_2O_2 exist in the batch reactor and the CSTR at a high flowrate, but the pH oscillations in a CSTR at a low flowrate originates from proton positive and negative feedback in the oxidation of KSCN. The oscillation of non-catalyzed oxidation of KSCN by hydrogen peroxide in a CSTR can be found. Also we have observed whether Cu^(2+) exists or not in the batch system, the pH increases to near neutral ultimately after pH drops twice.
文摘采用电位计法比较了活性纳米碳酸钙pH值测试过程中过滤、暴露时间、乙醇浸润量、温度、回旋振荡时间等对活性纳米碳酸钙pH值测试结果的影响。较佳的测试条件为:取(10±0.01)g活性纳米碳酸钙经乙醇浸润,加入100 m L无CO_2的水,在(50±1)℃下回旋振荡30 min,待悬浮液冷却至(25±1)℃,过滤,测试滤液的pH值。
文摘为优化pH值的测试影响因素,采用GB/T7573-2009和JIS L 1096-2010两种方法,选择试样大小、振荡时间和萃取液静置时间为自变量,pH值为响应面值,通过单因素试验、Box-Benhnken中心组合试验和响应面分析法,指明了影响pH值测试的显著性因素,并探讨了3个因素交互作用对pH值测试的影响,得到二次多元回归方程,确定了pH值的较优测试条件:试样大小0.5mm×0.5mm,振荡时间1h,萃取液静置时间1h。GB/T7573-2009的测试结果与JIS L 1096-2010的测试结果对比表明,GB/T7573-2009的测试结果一般稍大于JIS L1096-2010的结果。
