Removal of Co(II) and Ni(II) ions from contaminated water using silica gel functionalized with EDTA and/or DTPA as chelating agents

Eveliina Repo, Tonni Agustiono Kurniawan, Jolanta K. Warchol, Mika E.T. Sillanpää

Research output: Contribution to journalArticlepeer-review

178 Citations (Scopus)

Abstract

In this study, the removal of Co(II) and Ni(II) ions from contaminated water was investigated using silica gel materials functionalized with both ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA). The modified adsorbents were characterized using elemental analysis, surface area and pore size analysis, and zeta potential analysis. The adsorption and regeneration studies were conducted in batch mode. The optimum conditions for the removal of both metals at an initial concentration of 10 mg/L were 2 g/L of dose, pH 3, 50 rpm of agitation speed and 4 h of contact time. The removal of Co(II) and Ni(II) by EDTA- and/or DTPA-modified silica gels was substantially higher than that by their unmodified form. The maximum Co(II) and Ni(II) uptakes by the EDTA-modified silica gel were 20.0 and 21.6 mg/g, comparable to their adsorption capacities by DTPA-modified silica gel (Co(II): 16.1 mg/g; Ni(II): 16.7 mg/g). At the same concentration of 10 mg/L, the removal of both metals by the modified adsorbents ranged from 96% to 99%. The two-site Langmuir model was representative to simulate adsorption isotherms. The kinetics of Co(II) and Ni(II) adsorption by modified silica gels followed pseudo-second-order.

Original languageEnglish
Pages (from-to)1071-1080
Number of pages10
JournalJournal of Hazardous Materials
Volume171
Issue number1-3
DOIs
Publication statusPublished - 15 Nov 2009
Externally publishedYes

Keywords

  • Adsorption
  • Environmental protection
  • Heavy metal removal
  • Surface modification
  • Wastewater treatment

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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