采用碱中和滴定法合成羟基铝的过程中影响十三聚铝[Al_(13)]^(7+)含量的因素较多。选取了总铝浓度、碱化度、反应温度和碱化率等4个主要因素进行了综合优化研究,分析各因素的敏感性影响程度,最终确定合成[Al_(13)]^(7+)的最佳条件组合。...采用碱中和滴定法合成羟基铝的过程中影响十三聚铝[Al_(13)]^(7+)含量的因素较多。选取了总铝浓度、碱化度、反应温度和碱化率等4个主要因素进行了综合优化研究,分析各因素的敏感性影响程度,最终确定合成[Al_(13)]^(7+)的最佳条件组合。对4个因素分别选取了代表性的3个水平,运用正交试验设计原理建立了9组实验方案,根据确立的方案合成羟基铝溶液并进行27Al-NMR检测,然后以各铝形态的含量为指标进行极差分析。分析结果表明,4个因素中碱化度影响最显著,总铝浓度次之,反应温度和碱化率显著性较弱;合成[Al_(13)]^(7+)的最佳因素组合为总铝浓度为0.1 mol/L、反应温度为60℃、碱化度为2.5和碱化率为50 m L/min。展开更多
In this paper a polyaluminum chloride solution with high Al13 content was prepared and used as raw material for preparation ofγ-Al2O3.The texture and crystalline phase of the prepared alumina samples were characteriz...In this paper a polyaluminum chloride solution with high Al13 content was prepared and used as raw material for preparation ofγ-Al2O3.The texture and crystalline phase of the prepared alumina samples were characterized by energy dispersive X-ray spectroscopy(EDX) ,X-ray diffraction,transmission electron microscope(TEM) and nuclear magnetic resonance(NMR) analyses.The effects of alkaline solution and calcination temperature were investigated.The results showed that alkaline solution including NH3·H2O and NaOH had little effect on the alumina sample formation.The impurities of NH4Cl and NaCl in solution can be removed through repeated washing by EDX analysis.Calcination temperature had a significant effect on alumina crystal phase.The alumina sample can transform completely toγ-Al2O3 in the subsequent heating from 600°C to 800°C.It is very interesting that Al13 can be existed inγ-Al2O3 phase even after calcinations.The results indicate that polyaluminum chloride with high Al13 content is an effective material to prepareγ-Al2O3.展开更多
The optimum conditions for preparation of Al 13 sulfate were investigated.Some important parameters such as the ratio of n( OH - ) / n( Al ) ,reaction temperature,base injection rate,mixing intensity and ageing tim e ...The optimum conditions for preparation of Al 13 sulfate were investigated.Some important parameters such as the ratio of n( OH - ) / n( Al ) ,reaction temperature,base injection rate,mixing intensity and ageing tim e were identified.The hydroxyl ligand number and aging time are determinate fac tors for the forming of Al 13 .The nice tetrahedral sulfate was characterized by XRD and SEM,and the mol ecular formula was inferred to be[NaAlO 4 Al 12 (OH) 24 (H 2 O) 12 ](SO 4 ) 4 .This crystal was used as standard matter for preparation of polynuclear Al species(Al 13 ).The purity,stability and storage condition of the polynuclear Al 13 solution were explored.展开更多
Poly(aluminum chloride)(PAC) solutions of different basicity were prepared from pure aluminum foil and hydrochloric acid. Aluminum species were investigated by 27Al NMR spectroscopy and the tridecameric polycation Al ...Poly(aluminum chloride)(PAC) solutions of different basicity were prepared from pure aluminum foil and hydrochloric acid. Aluminum species were investigated by 27Al NMR spectroscopy and the tridecameric polycation Al 13 was detected. With the increase of PAC′s basicity, the molar ratio of Al 13 to Al m in PAC increases. The jar tests with kaolin water and water from Huangpu River at the same PACs dosage showed that the more basicity and content of Al 13, the more effective the coagulation effect on water with middle-high turbidity, while only less effect of the basicity was observed on water with low turbidity.展开更多
文摘采用碱中和滴定法合成羟基铝的过程中影响十三聚铝[Al_(13)]^(7+)含量的因素较多。选取了总铝浓度、碱化度、反应温度和碱化率等4个主要因素进行了综合优化研究,分析各因素的敏感性影响程度,最终确定合成[Al_(13)]^(7+)的最佳条件组合。对4个因素分别选取了代表性的3个水平,运用正交试验设计原理建立了9组实验方案,根据确立的方案合成羟基铝溶液并进行27Al-NMR检测,然后以各铝形态的含量为指标进行极差分析。分析结果表明,4个因素中碱化度影响最显著,总铝浓度次之,反应温度和碱化率显著性较弱;合成[Al_(13)]^(7+)的最佳因素组合为总铝浓度为0.1 mol/L、反应温度为60℃、碱化度为2.5和碱化率为50 m L/min。
基金Supported by National Natural Science Foundation of China（50708109 40673003） the Scientific Research Foundation for the Returned Overseas Chinese Scholars State Education Ministry（ITLXHG2009071702） the Special Fund from the State Key Laboratory of Environmental Aquatic Chemistry（09Y02ESPCR）
文摘In this paper a polyaluminum chloride solution with high Al13 content was prepared and used as raw material for preparation ofγ-Al2O3.The texture and crystalline phase of the prepared alumina samples were characterized by energy dispersive X-ray spectroscopy(EDX) ,X-ray diffraction,transmission electron microscope(TEM) and nuclear magnetic resonance(NMR) analyses.The effects of alkaline solution and calcination temperature were investigated.The results showed that alkaline solution including NH3·H2O and NaOH had little effect on the alumina sample formation.The impurities of NH4Cl and NaCl in solution can be removed through repeated washing by EDX analysis.Calcination temperature had a significant effect on alumina crystal phase.The alumina sample can transform completely toγ-Al2O3 in the subsequent heating from 600°C to 800°C.It is very interesting that Al13 can be existed inγ-Al2O3 phase even after calcinations.The results indicate that polyaluminum chloride with high Al13 content is an effective material to prepareγ-Al2O3.
文摘The optimum conditions for preparation of Al 13 sulfate were investigated.Some important parameters such as the ratio of n( OH - ) / n( Al ) ,reaction temperature,base injection rate,mixing intensity and ageing tim e were identified.The hydroxyl ligand number and aging time are determinate fac tors for the forming of Al 13 .The nice tetrahedral sulfate was characterized by XRD and SEM,and the mol ecular formula was inferred to be[NaAlO 4 Al 12 (OH) 24 (H 2 O) 12 ](SO 4 ) 4 .This crystal was used as standard matter for preparation of polynuclear Al species(Al 13 ).The purity,stability and storage condition of the polynuclear Al 13 solution were explored.
文摘Poly(aluminum chloride)(PAC) solutions of different basicity were prepared from pure aluminum foil and hydrochloric acid. Aluminum species were investigated by 27Al NMR spectroscopy and the tridecameric polycation Al 13 was detected. With the increase of PAC′s basicity, the molar ratio of Al 13 to Al m in PAC increases. The jar tests with kaolin water and water from Huangpu River at the same PACs dosage showed that the more basicity and content of Al 13, the more effective the coagulation effect on water with middle-high turbidity, while only less effect of the basicity was observed on water with low turbidity.
