Nickel Sorption to Goethite and Montmorillonite in Presence of Citrate

Abstract

Mobility and bioavailability of nickel (Ni) in soil strongly depends on the interaction between Ni(II), ligands, and sorbents like organic matter and minerals. Sorption of Ni(II) and Ni(II)-citrate complexes to goethite and montmorillonite was examined in batch experiments with and without citrate as ligand in the pH range pH 4-7.5. Without citrate, montmorillonite shows higher Ni sorption than goethite. Citrate strongly decreases Ni sorption to montmorillonite; in presence of 100 microM citrate goethite becomes a stronger Ni sorbent than montmorillonite. Ni and citrate sorption was modeled successfully using the diffuse double layer model with the following reactions: Goethite: 3 [triple bond]FeOH + Citrate(3-) + 3H+ <=> [triple bond] Fe3Citrate + 3H2O, [triple bond]FeOH + Ni2+ <=> [triple bond] FeONi + H+ and 2 [triple bond] FeOH + Citrate(3)- + Ni2+ <=> [triple bond] FeONiCitrate(2-) + H+. Montmorillonite: 2X- + Ni2+ <=> X2Ni and [triple bond] AIOH + Ni2+ <=> AIONi+ + H+. Sorption of Ni to a mixture of goethite and montmorillonite could be calculated by use of reactions and constants for the monomineral systems. Without citrate, the sorbed amount of Ni per mass unit in the mixture can be found as a simple average of sorption to the two single sorbents, while in presence of citrate Ni sorption to montmorillonite is strongly influenced by citrate sorption to goethite.

Interaction mechanism of radionickel on Na-montmorillonite: Influences of pH, electrolyte cations, humic acid and temperature

“…Sorption of Ni(II) onto mineral surfaces has been extensively studied since this process has significant effect on the transport properties [7][8][9][10][11][12][13]. There is no denying that the environmental condition has more or less influence on Ni(II) sorption and speciation.…”

“…The aforementioned researches were mainly focused on the investigation of sorption capability of minerals [7][8][9][10][11][12][13][14][15][16]. However, desorption reactions of radionuclides from mineral surface were the most relevant retention process for radionuclides with the surrounding conditions changing [17].…”

Sorption Speciation of Nickel(ii) onto Ca-Montmorillonite: Batch, EXAFS Techniques and Modeling

“…However, the species are usually determined in the absence of spectroscopic data that may provide more detailed structural information on surface complexes formed. [10][11][12] To make the sorption mechanisms onto montmorillonite system more reliable, SCM simulation basing on spectroscopic data is important. However, to date, only a few reports involve the combination of SCM with spectroscopic investigation, although this may offer a fundamental level investigation as far as we know.…”

Association of trace elements and dissolution rates of soil iron oxides

“…The initial greater release of these elements relative to Fe also suggests that some fraction of the element was present in a discrete solid or soluble phase or adsorbed on to Fe oxides. There are several reports indicating that these elements can be adsorbed by Fe oxides and/or incorporated into Fe-oxide structures (Quin et al 1988;Angove et al 1999;Christophi and Axe 2000;Manceau et al 2000;Wells et al 2006;Kaur et al 2009a;Marcussen et al 2009). The dissolution pattern for Ti was varied (Fig.…”