当前位置: X-MOL 学术ACS Earth Space Chem. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Influence of pH and Temperature on Basaluminite Dissolution Rates
ACS Earth and Space Chemistry ( IF 2.9 ) Pub Date : 2018-01-16 00:00:00 , DOI: 10.1021/acsearthspacechem.7b00128
Patricia Acero 1 , Karen A. Hudson-Edwards 1
Affiliation  

The processes, rates, and controlling factors of basaluminite [Al4(SO4)(OH)10·4H2O] dissolution were assessed using batch dissolution experiments in both H2SO4 and HCl at pH values of 2.4, 2.9–3.1, 3.5–3.6, and 4.0–4.1 and temperatures of ca. 279, 293, 303, and 312 K. Basaluminite dissolution is incongruent over most of the studied pH range, giving generally a lower Al/S ratio in solution than in the pristine basaluminite sample. The lower Al/S ratio may be at least partially explained by the preferential release of sulfate compared to Al from dissolving basaluminite. The dissolution rates range between 10–7.6 and 10–9.1 mol m–2 s–1. At 291–293 K, the slowest rates were observed at pH 4.1 in H2SO4 solutions, while at pH 3.0, the slowest rates were observed at 279 K in HCl solutions. Decreases in pH and increases in temperature increase dissolution rates. The influence of pH and temperature on the basaluminite dissolution rate, expressed as Al release, can be described by the following expression: rateAl = 107.3 ± 0.5aH+0.64 ± 0.04e–78 ± 3/RT, where rateAl is the basaluminite dissolution rate based on the rate of Al release from dissolving basaluminite (mol m–2 s–1), aH+ is the activity of hydrogen ions in solution, R is the universal gas constant (kJ mol–1 K–1), and T is the temperature (K). In light of the calculated value for the activation energy (78 ± 3 kJ mol–1), basaluminite dissolution appears to be surface-controlled. The reaction for basaluminite dissolution under the experimental conditions is proposed to be Al4(SO4)(OH)10·4H2O + 10H+→ 4Al3+ + SO42– + 14H2O.

中文翻译:

pH和温度对硅铝矾石溶解速率的影响

在pH值为2.4、2.9-3.1的H 2 SO 4和HCl中,采用间歇溶解实验评估了玄武岩[Al 4(SO 4)(OH)10 ·4H 2 O]的溶解过程,速率和控制因素。,3.5–3.6和4.0–4.1以及温度约为。279、293、303和312K。在大多数研究的pH范围内,硅铝矾石的溶解度均不一致,因此,与原始的玄武岩样品相比,溶液中的铝/硫比通常较低。较低的Al / S比可以至少部分地由与溶解玄武岩相比Al优先释放硫酸盐来解释。溶出度范围为10 –7.6至10 –9.1 mol m–2 s –1。在291–293 K下,在H 2 SO 4溶液中,在pH 4.1时观察到最慢的速率,而在pH 3.0下,在HCl溶液中,在279 K下观察到最慢的速率。pH值降低和温度升高会增加溶解速率。pH和温度对玄武岩溶解速率的影响(表示为Al的释放)可以用以下表达式表示:速率Al = 10 7.3±0.5 a H + 0.64±0.04 e –78±3 / RT,其中Al为基于溶解玄武岩中铝释放速率的玄武岩溶出速率(mol m –2 s –1),一个H +是氢离子在溶液中的活性,- [R是通用气体常数(千焦耳摩尔-1 ķ -1),和Ť是温度(K)。根据活化能(78±3 kJ mol –1)的计算值,玄武岩的溶解似乎是受表面控制的。为在试验条件下basaluminite溶解反应建议是Al 4(SO 4)(OH)10 ·4H 2 O + 10H + →4AL 3+ + SO 4 2- + 14H 2 O.
更新日期:2018-01-16
down
wechat
bug