铝酸钠溶液中Al(OH)_3吸附草酸盐行为研究
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摘要
通过模拟拜耳法晶种分解过程研究了铝酸钠溶液中Al(OH)_3对草酸盐的吸附平衡和动力学行为,并考察了草酸盐初始浓度和Al(OH)_3粒度对吸附的影响规律.结果表明:Al(OH)_3对草酸钠有较大的吸附能力,随草酸钠浓度的升高和Al(OH)_3粒度的细化,草酸钠吸附率随之升高,达到平衡的时间也相应缩短;不同粒度Al(OH)_3的吸附能力不同,这跟Al(OH)_3的比表面积有很大关系; Al(OH)_3对草酸钠的等温吸附符合Freundlich模型,吸附动力学符合准二级动力学方程,吸附行为为多分子层吸附,同时存在物理和化学吸附过程.
The adsorption equilibrium and kinetics of oxalate on Al(OH)_3 in sodium aluminate solution were studied by simulating the seed precipitation of the Bayer process,and the effects of initial oxalate concentration and the particle size of Al(OH)_3 on adsorption were also investigated.The results showed that Al(OH)_3 has a good adsorption ability on sodium oxalate. With increasing initial sodium oxalate concentration and decreasing particle size of Al(OH)_3,the equilibrium adsorption rate increases and the equilibrium adsorption time decreases. The adsorption capacity for different particle size of Al(OH)_3 is different due to the different specific surface area. The adsorption isotherm pattern of sodium oxalate on Al(OH)_3 fits the Freundlich model well and the adsorption process can be described by the pseudo-second-order equation. The adsorption of oxalate on Al(OH)_3 is a multilayer adsorption,associated with physical and chemical adsorption processes.
The adsorption equilibrium and kinetics of oxalate on Al(OH)_3 in sodium aluminate solution were studied by simulating the seed precipitation of the Bayer process,and the effects of initial oxalate concentration and the particle size of Al(OH)_3 on adsorption were also investigated.The results showed that Al(OH)_3 has a good adsorption ability on sodium oxalate. With increasing initial sodium oxalate concentration and decreasing particle size of Al(OH)_3,the equilibrium adsorption rate increases and the equilibrium adsorption time decreases. The adsorption capacity for different particle size of Al(OH)_3 is different due to the different specific surface area. The adsorption isotherm pattern of sodium oxalate on Al(OH)_3 fits the Freundlich model well and the adsorption process can be described by the pseudo-second-order equation. The adsorption of oxalate on Al(OH)_3 is a multilayer adsorption,associated with physical and chemical adsorption processes.
引文
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[2] Power G,Loh J S,Vernon C. Organic compounds in the processing of lateritic bauxites to alumina. Part 2:effects of organics in the Bayer process[J]. Hydrometallurgy,2012,127/128:125-149.
[3] Taylor M,Harris D J,Chen H T,et al. Methods and compositions for the removal of impurities and water from the Bayer process:7972580[P]. 2011-07-05.
[4] Fu W,Vaughan J,Gillespie A. In situ AFMinvestigation of heterogeneous nucleation and growth of sodium oxalate on industrial gibbsite surfaces in concentrated alkaline solution[J]. Chemical Engineering Science,2015,126:399-405.
[5]武小玲.硫酸高铈容量法测定草酸钠[J].新疆医科大学学报,1999,22(2):148-149.(Wu Xiao-ling. The method of measuring sodium oxalate by ceric sulfate[J]. Journal of Xinjiang Medical University,1999,22(2):148-149.)
[6] Salmi T,Tolvanen P,Warna J,et al. Mathematical modeling of starch oxidation by hydrogen peroxide in the presence of an iron catalyst comple[J]. Chemical Engineering Science,2016,146(2):19-25.
[7]梁明华,苗健.一种咪唑啉缓蚀剂对油口用P110钢CO2腐蚀的缓蚀行为[J].腐蚀与防护,2013,34(5):396-398.(Liang Ming-hua,Miao Jiang. Corrosion inhibition behavior of an iimidazoline iihibitor for P110 steel CO2[J]. Corrosion and Protection,2013,34(5):396-398.)
[8]韩冲,杨合,薛向欣.亚甲基蓝在CaTiO3上的吸附动力学[J].东北大学学报(自然科学版),2015,36(1):74-76.(Han Chong,Yang He,Xue Xiang-xin. Adsorption kinetics of methylene blue on CaTiO3[J]. Journal of Northeastern University(Natural Science),2015,36(1):74-76.)
[9] Do D D. Adsorption analysis:equilibria and kinetics[M].London:Imperial College Press,1998:33-72.
[10] Elsherbiny A S. Adsorption kinetics and mechanism of acid dye onto montmorillonite from aqueous solutions:stoppedflowmeasurements[J]. Applied Clay Science,2013,83/84:56-62.