The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed ...The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed by UV-VIS spectrophotometric measurements at controlled operating conditions. The organic content of reaction samples was measured to verify the process efficiency in dye mineralization. According to current results, almost complete color removal was obtained for ozonation within about 1 h reaction time. The reduction of the organic load was almost 80% from its original while initial sulphur content decreased to 32.5%. Dye conversion of 100% was obtained by means of a photocatalytic process using TiO2 as catalyst at 294 nm irradiated UV light. This complete color removal for the catalytic process was observed within 7 min of reaction time. The calculated initial rate of reaction of photocatalysis treatment was 8 times faster than that of ozonolysis. However, the remaining organic load of photocatalysis was almost 88% from its original while the final sulphur content was 27.3%. This contrasting behavior of the performance of the type of oxidation process stressed importance of physicochemical phenomena and intermediates molecules present during dye degradation. An insightful and mechanistic aspect of the dye oxidation was developed by performing quantumchemical calculations.展开更多
Long-term research on key techniques of clean utilization of potassic rocks from over twenty localities has been performed to settle the shortage of soluble potassium resources in China. The results show that K-feldsp...Long-term research on key techniques of clean utilization of potassic rocks from over twenty localities has been performed to settle the shortage of soluble potassium resources in China. The results show that K-feldspar as the principal mineral enriched in potassium could be decomposed in the media of Ca（OH）_2, NaOH, KOH-H_2O solution via hydrothermal treatment, into tobermorite, hydroxylcancrinite, and kalsilite respectively. By further processing, these compounds are feasible for being as slow-release carrier of potassium nitrate, extracting alumina, and preparing farm-oriented fertilizers of potassium sulphate and nitrate. Correspondingly, the filtrate is KOH,（Na, K）_2SiO_3, and K_2SiO_3 solution, from which potassium carbonate, sulphate, nitrate, and phosphate could be easily fabricated. As NaO H and KOH are recycled in the processing chains by causticizing sodium and/or potassium metasilicate solutions, the hydrothermal alkaline techniques as developed in this research have several advantages as lower consumption of disposable mineral resources and energy, maximized utilization of potassic mineral resources, as well as clean productions etc. Based on the approaches presented in this paper, the technical system of efficiently utilizing insoluble potassium resources has been established. The hydrothermal alkaline methods are feasible to be industrialized on a large scale, thus resulting in decreasing imports of potash fertilizers, improving the pattern of potassium fertilizer consumption, and enhancing the supplying guarantee of potassium resource in China.展开更多
Agricultural potassium sulphate is one of the most important non-chloride potash, which is the main fertilizer of avoid chlorine crop. Soluble potassium resource is bare in China, while insoluble potassium resource wi...Agricultural potassium sulphate is one of the most important non-chloride potash, which is the main fertilizer of avoid chlorine crop. Soluble potassium resource is bare in China, while insoluble potassium resource with the main mineral of microcline is extremely abundant. The microcline powder used is collected from Mountain Changling, Luonan county of Shaanxi Province. The chemical analysis results showed that the main chemical components of the powder are SiO2, Al2O3 and K2O, the K2O content is up to 13.56% (shown in table 1).展开更多
Potassium bismuth titanate nanosized powders were prepared by the hydrothermal method using Ti(C_4H_9O)_4 and Bi(NO_3)_3·5H_2O as raw materials in alkaline solution.The phase composition,particle size and morphol...Potassium bismuth titanate nanosized powders were prepared by the hydrothermal method using Ti(C_4H_9O)_4 and Bi(NO_3)_3·5H_2O as raw materials in alkaline solution.The phase composition,particle size and morphology of the powders were studied by XRD and TEM analysis.The results showed that the powders were well crystallized and dispersed.The crystal phase of the powders was K_(0.5)Bi_(0.5)TiO_3 with the grain size of about 50 nm～100 nm.Hydrothermal temperature and alkaline concentrations had great effects on the phase composition and morphology of the resultant powders.Pure K_(0.5)Bi_(0.5)TiO_3 powders could be synthesized at 170℃～180℃with KOH concentration of 8 mol/L～12 mol/L.展开更多
Nanostructured K2Ti6O13 film photoelectrode produced in situ was prepared on indium-tin oxide (ITO) glass substrate by a sol-gel process and characterized by thermogravimetry (TG) and differential scanning calorimetry...Nanostructured K2Ti6O13 film photoelectrode produced in situ was prepared on indium-tin oxide (ITO) glass substrate by a sol-gel process and characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC), X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Visible diffuse reflectance and Raman spectrometry. The photoelectrochemical performance of K2Ti6O13 film was assessed by electrochemical method. The analytical results showed that the K2Ti6O13 film had a strong and wide absorption in the ultraviolet and visible light range. The band gap energy (Eg) of the film shifted from 3.45 eV (bulk) to 3.05 eV (film). The flat-band potential (Efb) of K2Ti6O13 film was -0.67 V [vs. saturated calomel electrode (SCE)]. The transport of photogenerated electrons and holes was better in K2Ti6O13 film electrode than that in TiO2 film electrode. The photoelectrochemical response of K2Ti6O13 photoelectrode was increased in electrolyte solution with KOH, compared with that in the solution without KOH. The adsorption of OH- on the nanofilm acted as the surface activity center. The mechanism of photolysis was analyzed in terms of photoelectrochemical behavior.展开更多
文摘The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed by UV-VIS spectrophotometric measurements at controlled operating conditions. The organic content of reaction samples was measured to verify the process efficiency in dye mineralization. According to current results, almost complete color removal was obtained for ozonation within about 1 h reaction time. The reduction of the organic load was almost 80% from its original while initial sulphur content decreased to 32.5%. Dye conversion of 100% was obtained by means of a photocatalytic process using TiO2 as catalyst at 294 nm irradiated UV light. This complete color removal for the catalytic process was observed within 7 min of reaction time. The calculated initial rate of reaction of photocatalysis treatment was 8 times faster than that of ozonolysis. However, the remaining organic load of photocatalysis was almost 88% from its original while the final sulphur content was 27.3%. This contrasting behavior of the performance of the type of oxidation process stressed importance of physicochemical phenomena and intermediates molecules present during dye degradation. An insightful and mechanistic aspect of the dye oxidation was developed by performing quantumchemical calculations.
基金granted by China Geological Survey Project(12120113087700)Fundamental Research Funds for the Central Universities(2652014017)+10 种基金the National Eleventh Five-year Supporting Plan for Science and Technology(2006BAD10B04)Specialized Research Funds for Doctoral Program of Higher Education(1999049114)supported by the Provincial Science and Technology Programs of Henan(0524250042)Inner Mongolia(20020307)Shanxi(001065)Beijing(953500400)enterprises of Shaanxi Daqin Potassium Industry CorporationTongling Chemical Industry Group CorporationShanxi Ziguang Potassium Industry CorporationHenan Qianhe Mining Corporationthe Geological Survey of Tianjin
文摘Long-term research on key techniques of clean utilization of potassic rocks from over twenty localities has been performed to settle the shortage of soluble potassium resources in China. The results show that K-feldspar as the principal mineral enriched in potassium could be decomposed in the media of Ca（OH）_2, NaOH, KOH-H_2O solution via hydrothermal treatment, into tobermorite, hydroxylcancrinite, and kalsilite respectively. By further processing, these compounds are feasible for being as slow-release carrier of potassium nitrate, extracting alumina, and preparing farm-oriented fertilizers of potassium sulphate and nitrate. Correspondingly, the filtrate is KOH,（Na, K）_2SiO_3, and K_2SiO_3 solution, from which potassium carbonate, sulphate, nitrate, and phosphate could be easily fabricated. As NaO H and KOH are recycled in the processing chains by causticizing sodium and/or potassium metasilicate solutions, the hydrothermal alkaline techniques as developed in this research have several advantages as lower consumption of disposable mineral resources and energy, maximized utilization of potassic mineral resources, as well as clean productions etc. Based on the approaches presented in this paper, the technical system of efficiently utilizing insoluble potassium resources has been established. The hydrothermal alkaline methods are feasible to be industrialized on a large scale, thus resulting in decreasing imports of potash fertilizers, improving the pattern of potassium fertilizer consumption, and enhancing the supplying guarantee of potassium resource in China.
基金Project supported by National Key Technologies Research and Development Program for 11th Five-year Plan (No. 2006 BAD10B04)China Geological Survey Project (No. 12120113087700)
文摘Agricultural potassium sulphate is one of the most important non-chloride potash, which is the main fertilizer of avoid chlorine crop. Soluble potassium resource is bare in China, while insoluble potassium resource with the main mineral of microcline is extremely abundant. The microcline powder used is collected from Mountain Changling, Luonan county of Shaanxi Province. The chemical analysis results showed that the main chemical components of the powder are SiO2, Al2O3 and K2O, the K2O content is up to 13.56% (shown in table 1).
文摘Potassium bismuth titanate nanosized powders were prepared by the hydrothermal method using Ti(C_4H_9O)_4 and Bi(NO_3)_3·5H_2O as raw materials in alkaline solution.The phase composition,particle size and morphology of the powders were studied by XRD and TEM analysis.The results showed that the powders were well crystallized and dispersed.The crystal phase of the powders was K_(0.5)Bi_(0.5)TiO_3 with the grain size of about 50 nm～100 nm.Hydrothermal temperature and alkaline concentrations had great effects on the phase composition and morphology of the resultant powders.Pure K_(0.5)Bi_(0.5)TiO_3 powders could be synthesized at 170℃～180℃with KOH concentration of 8 mol/L～12 mol/L.
基金Supported by the National Natural Science Foundation of China (No. 20246002 20236010)+1 种基金National High Technology Research and Development Program of China (No. 2003CB615700)The Key Science Foundation of Jiangsu Province (No. BK 2004215)
文摘Nanostructured K2Ti6O13 film photoelectrode produced in situ was prepared on indium-tin oxide (ITO) glass substrate by a sol-gel process and characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC), X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Visible diffuse reflectance and Raman spectrometry. The photoelectrochemical performance of K2Ti6O13 film was assessed by electrochemical method. The analytical results showed that the K2Ti6O13 film had a strong and wide absorption in the ultraviolet and visible light range. The band gap energy (Eg) of the film shifted from 3.45 eV (bulk) to 3.05 eV (film). The flat-band potential (Efb) of K2Ti6O13 film was -0.67 V [vs. saturated calomel electrode (SCE)]. The transport of photogenerated electrons and holes was better in K2Ti6O13 film electrode than that in TiO2 film electrode. The photoelectrochemical response of K2Ti6O13 photoelectrode was increased in electrolyte solution with KOH, compared with that in the solution without KOH. The adsorption of OH- on the nanofilm acted as the surface activity center. The mechanism of photolysis was analyzed in terms of photoelectrochemical behavior.
