Behavior of ammonium adsorption by clay mineral halloysite

Ammonium pollution becomes severe during mining of ionic rare earth-ores in southern China. As one of the main clay minerals in soils of ionic rare earth mines, halloysite plays an important role in ammonium adsorption. In this study, the saturated adsorption capacity, factors affecting adsorption a...

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Bibliographic Details
Published inTransactions of Nonferrous Metals Society of China Vol. 27; no. 7; pp. 1627 - 1635
Main Authors JING, Qing-xiu, CHAI, Li-yuan, HUANG, Xiao-dong, TANG, Chong-jian, GUO, Huan, WANG, Wei
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 01.07.2017
Subjects
adsorption
ammonium pollution
dynamics
halloysite
ionic rare earth mining area
adsorption
dynamics
ammonium pollution
ionic rare earth mining area
halloysite
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Summary:Ammonium pollution becomes severe during mining of ionic rare earth-ores in southern China. As one of the main clay minerals in soils of ionic rare earth mines, halloysite plays an important role in ammonium adsorption. In this study, the saturated adsorption capacity, factors affecting adsorption and adsorption kinetics of halloysite for ammonium were investigated. The results indicated that the ammonium adsorption of halloysite was saturated with 1.66 mg/g at 303 K, pH of 5.6 and initial ammonium concentration of 600 mg/L (about half of the actual initial in-situ leaching concentration). When the initial concentration of –N, pH values and temperatures (288 K to 313 K) increased, the ammonium adsorption capacity of halloysite increased. The ammonium isothermal adsorption of halloysite matched the Langmuir and Freundlich isotherms. The adsorption process of ionic rare earth mining soils for ammonium was favorable. And the adsorption process followed closely the pseudo-second kinetic equation.
ISSN:1003-6326
DOI:10.1016/S1003-6326(17)60185-7