scholarly journals Sorption of Heavy Metals on Clay Minerals and Oxides: A Review

2019 ◽  
Author(s):  
Ifeoma Mary Ugwu ◽  
Onyedikachi Anthony Igbokwe
Keyword(s):  
Heavy Metals ◽  
Clay Minerals

The role of clay minerals and the effect of H+ ions on removal of heavy metal (Pb2+) from contaminated soils

2000 ◽  
Vol 37 (2) ◽  
pp. 296-307 ◽  
Author(s):  
Loretta Y Li ◽  
Raymond S Li
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Surface Charge ◽  
Clay Minerals ◽  
Contaminated Soils ◽  
Surface Charges ◽  
Buffer Solution ◽  
Soil System ◽  
Variable Charge ◽  
Acid Leach

The importance of the surface charge of clay minerals (fixed or variable) and the effect of H+ ions on the adsorption and removal of Pb2+ ions from contaminated soil are investigated using kaolinite (variable charge) and two illitic (fixed charge) soils with pH 3.9 and 9.2. The adsorption-desorption characteristics of Pb2+ ions were determined using batch equilibrium tests and acid leach tests with various acids used to leach the soils. Under the same adsorption conditions, illitic soil adsorbed much more Pb2+ ions than kaolinite. The difference is largely due to the surface charges on the clay minerals. Removal of Pb2+ ions from variable-charge minerals (e.g., kaolinite) requires much less effort than removal of Pb2+ ions from constant-charge minerals (e.g., illite). The surface charge of a clay mineral has an important effect. By increasing the number of H+ ions available in the soil system with a buffer solution such as NaOAc-HOAc, heavy metals adsorbed on the clay surface are expelled to pore water. The increase in H+ ions in the soil system also assists in dissolving any metal carbonates, thereby increasing the solubility of heavy metals in illitic soil. The more H+ ions available in the pore fluid, the more Pb2+ ions can be released from the system.Key words: clay minerals, sorption, desorption, heavy metal, hydrogen ion, electrokinetic, acid leach.

Experimental study of the selective adsorption of heavy metals onto clay minerals

2000 ◽  
Vol 19 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Hongping He ◽  
Jiugao Guo ◽  
Xiande Xie ◽  
Jinlian Peng
Keyword(s):  
Heavy Metals ◽  
Experimental Study ◽  
Clay Minerals ◽  
Selective Adsorption
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