Ni adsorption and Ni–Al LDH precipitation in a sandy aquifer: An experimental and mechanistic modeling study

• Published in: Environmental pollution (1987) Vol. 159; no. 3; pp. 716 - 721
• Main Authors: Regelink, Inge C., Temminghoff, Erwin J.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2011; Elsevier
• Subjects: Adsorption; Aluminum; Aluminum - analysis; Aluminum - chemistry; Applied sciences; Aquifers; Chemical Precipitation; clay; dissolution kinetics; Environmental Restoration and Remediation - methods; Exact sciences and technology; Geologic Sediments; gibbsite; Hydrogen-Ion Concentration; interface; Metal immobilization; minerals; Mining; Models, Theoretical; Nickel; Nickel - analysis; Nickel - chemistry; nickel sorption; Ni–Al Layered Double Hydroxide; Pollution; Precipitation; pyrophyllite; Sandy soils; Silicon Dioxide - analysis; Silicon Dioxide - chemistry; soil; Soil Pollutants - analysis; Soil Pollutants - chemistry; Solubility; Speciation modeling; stability; Netherlands; Europe; Speciation modeling; Metal immobilization; Ni–Al Layered Double Hydroxide; Pollutant behavior; Pollution control; Immobilization; Sandy soil; Experimental study; Soil pollution; Modeling; Heavy metal; Aquifer system; Trace element; Ni―Al Layered Double Hydroxide; Adsorption; Layered double hydroxide; Nickel; Water pollution; Pollution abatement; Mining industry; Speciation
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2010.11.038

Mining activities and industries have created nickel (Ni) contaminations in many parts of the world. The objective of this study is to increase our understanding of Ni adsorption and Nickel–Aluminium Layered Double Hydroxide (Ni–Al LDH) precipitation to reduce Ni mobility in a sandy soil aquifer. At pH ≥7.2 both adsorption and Ni–Al LDH precipitation occurred. In batch experiments with the sandy soil up to 70% of oxalate-extractable Al was taken up in LDH formation during 56 days. In a long term column experiment 99% of influent Ni was retained at pH 7.5 due to Ni adsorption (≈34%) and Ni–Al LDH precipitation (≈66%) based on mechanistic reactive transport modeling. The subsequent leaching at pH 6.5 could be largely attributed to desorption. Our results show that even in sandy aquifers with relatively low Al content, Ni–Al LDH precipitation is a promising mechanism to immobilize Ni. ► Ni solubility is controlled by adsorption and Ni–Al LDH precipitation. ► Solubility product of Ni–Al LDH. ► Reactive transport modeling including adsorption and precipitation. ► Ni is immobilized by formation of stable Ni–Al LDH precipitates. The mobility of Ni in contaminated aquifers controlled by both Ni adsorption and Ni–Al LDH precipitation.