Effect of Pb and Cd on Cu adsorption by sand–bentonite liners

2005 ◽  
Vol 32 (1) ◽  
pp. 241-249 ◽  
Author(s):  
Saleh Kaoser ◽  
Suzelle Barrington ◽  
Maria Elektorowicz ◽  
Li Wang
Keyword(s):  
Heavy Metal ◽  
Sequential Extraction ◽  
Metal Cations ◽  
Pressure Head ◽  
Breakthrough Curves ◽  
Metal Adsorption ◽  
Liner Material ◽  
Selective Sequential Extraction ◽  
Total Metal ◽  
Sequential Extraction Analysis

The mobility of Cu alone and in the presence of Cd (compatible) and Pb (incompatible) was studied using laboratory columns packed with a 95 wt.% sand and 5 wt.% bentonite mixture. The liner material was subjected to one of four heavy metal solutions using a pressure head of 7 kPa: 2.0 cmol(+) Cu/L solution; 1.0 cmol(+) Cu and 1.0 cmol(+) Cd/L solution for a total of 2.0 cmol(+)/L solution; and 1.0 cmol(+) Cu and 1.0 cmol(+) Pb/L solution for a total of 2.0 cmol(+)/L solution. The effluents and the liner samples were analyzed for Cu, Pb, and Cd. The breakthrough curves indicated that Cd was the most mobile of the metal cations, whereas Pb was the least. Total metal adsorption was greatest for Cu with Pb, followed by that of Cu with Cd, and then that of Cu alone, showing that Cu is compatible with Cd but not Pb. The selective sequential extraction analysis indicated that most of the Cu was precipitated by the carbonate and hydroxide fractions.Key words: Cd, Pb, Cu, sand–bentonite liners, adsorption, leaching.

Selective sequential extraction analysis of heavy-metal retention in soil

1993 ◽  
Vol 30 (5) ◽  
pp. 834-847 ◽  
Author(s):  
Raymond N. Yong ◽  
Rosa Galvez-Cloutier ◽  
Yuwaree Phadungchewit
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Sequential Extraction ◽  
Soil Solution ◽  
Solution Ph ◽  
Selective Sequential Extraction ◽  
Metal Retention ◽  
Ph Values ◽  
Sequential Extraction Method ◽  
Sequential Extraction Analysis

The selective sequential extraction method of analysis is used in this study to determine the distribution of heavy metals in some clay soils, to assist in evaluation of the role of the various clay soil solids (clay minerals, organics, amorphous materials, and carbonates) in heavy-metal retention capability as a function of acidity of the leachate. The chemical speciation model MINTEQ (metal speciation equilibrium model for surface and groundwater) is used to calculate the probable percent distribution of different species of heavy metals present in the leachate used. The selective sequential extraction method is based on the fact that different forms of heavy metals that are retained in soil (e.g., as oxides, hydroxides, carbonates, bound with organic matter) can be extracted selectively by using appropriate reagents. The results show that heavy metals can be retained in the four clay soils studied by several soil phases or mechanisms such as exchangeable, carbonate, hydroxide, and organic phases. The retention of heavy metals in any phase depends on soil solution pH, soil constituents, and the type of heavy metal. At high soil solution pH values, retention of heavy metal by precipitation mechanisms prevails, whereas at low soil solution pH, retention by cation exchange mechanisms becomes dominant. The results from the selective sequential extraction analysis support the conclusion of the significance of soil buffer capacity with regard to heavy-metal retention. The capacity of the soils to retain high amounts of heavy metals as they receive increasing amounts of acid (i.e., as the pH is reduced) depends directly on the soil initial pH values and on their buffer capacities. Key words : selective sequential analysis, exchangeable cations, heavy metals, equilibrium models, oxides.

A Comparative Study on the Pollution and Speciation Characteristics of Heavy Metals between the Gold and Iron Mine Tailings of the Upstream Area of Miyun Reservoir, Beijing

2012 ◽  
Vol 518-523 ◽  
pp. 1412-1416 ◽  
Author(s):  
Xing Xing Huang ◽  
Hong Bing Ji ◽  
Cai Li ◽  
Fei Qin ◽  
Qian Li ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Sequential Extraction ◽  
Mine Tailings ◽  
Mine Tailing ◽  
Gold Mine ◽  
Miyun Reservoir ◽  
Total Metal ◽  
Iron Mine ◽  
Gold Mine Tailings

In order to have a comparative investigation of the pollution and speciation characteristics of heavy metals between the gold and iron mine tailings of the upstream areas of Miyun Reservoir, the tailing samples from the typical gold and iron mines were analyzed. The total metal concentration is determined by acid digestion and the chemical fractionation of metal by the Tessier sequential extraction method. It is found that compared to background values of Beijing, the heavy metal in both gold and iron mine tailings is higher, while the heavy metal in gold mine tailings is higher than that of iron mine tailings, with Mn as an exception. Mercury is the most serious pollution element in gold mine tailings. Results of the sequential extraction suggest that the exchangeable of Cd exhibits the highest percentage of total metal in gold and iron mine tailings（15% and 6.5% of the total metal, respectively) among Cd, Mn, Zn, Cu, Pb, Cr. In the majority of iron mine tailing samples collected, large amounts of Cu were mainly associated with the organic form. The percentage of the bioavailable metals in both gold and iron mine tailing samples follows the order: Cd>Mn>Zn>Cu>Pb>Cr.

Regeneration of chitosan-based adsorbents used in heavy metal adsorption: A review

2019 ◽  
Vol 224 ◽  
pp. 373-387 ◽  
Author(s):  
Mohammadtaghi Vakili ◽  
Shubo Deng ◽  
Giovanni Cagnetta ◽  
Wei Wang ◽  
Pingping Meng ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Adsorption ◽  
Heavy Metal Adsorption

scholarly journals Combined Influence of Low-Grade Metakaolins and Natural Zeolite on Compressive Strength and Heavy Metal Adsorption of Geopolymers

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 486
Author(s):  
Alcina Johnson Sudagar ◽  
Slávka Andrejkovičová ◽  
Fernando Rocha ◽  
Carla Patinha ◽  
Maria R. Soares ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Compressive Strength ◽  
Natural Zeolite ◽  
Metal Adsorption ◽  
Low Grade ◽  
Heavy Metal Adsorption ◽  
Adsorption Model ◽  
X Ray ◽  
Adsorption Capacities

Metakaolins (MKs) prepared from low-grade kaolins located in the Alvarães (A) and Barqueiros (B) regions of Portugal were used as the aluminosilicate source to compare their effect on the compressive strength and heavy metal adsorption of geopolymers. Natural zeolite, an inexpensive, efficient adsorbent, was used as an additive in formulations to enhance geopolymers’ adsorption capacities and reduce MK utilization’s environmental footprint. Geopolymers were synthesized with the replacement of MK by zeolite up to 75 wt.% (A25, B25—25% MK 75% zeolite; A50, B50—50% MK 50% zeolite; A75, B75—75% MK 25% zeolite; A100, B100—100% MK). The molar ratios of SiO2/Al2O3 and Na2O/Al2O3 were kept at 1 to reduce the sodium silicate and sodium hydroxide environmental impact. Geopolymers’ crystallography was identified using X-ray diffraction analysis. The surface morphology was observed by scanning electron microscopy to understand the effect of zeolite incorporation. Chemical analysis using X-ray fluorescence spectroscopy and energy dispersive X-ray spectroscopy yielded information about the geopolymers’ Si/Al ratio. Compressive strength values of geopolymers obtained after 1, 14, and 28 days of curing indicate high strengths of geopolymers with 100% MK (A100—15.4 MPa; B100—32.46 MPa). Therefore, zeolite did not aid in the improvement of the compressive strength of both MK-based geopolymers. The heavy metal (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption tests exhibit relatively higher adsorption capacities of Barqueiros MK-based geopolymers for all the heavy metals except Cd2+. Moreover, zeolite positively influenced divalent cations’ adsorption on the geopolymers produced from Barqueiros MK as B75 exhibits the highest adsorption capacities, but such an influence is not observed for Alvarães MK-based geopolymers. The general trend of adsorption of the heavy metals of both MK-based geopolymers is Pb2+ > Cd2+ > Cu2+ > Zn2+ > Cr3+ when fitted by the Langmuir isotherm adsorption model. The MK and zeolite characteristics influence geopolymers’ structure, strength, and adsorption capacities.

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