Sorption studies of Cr(VI) from aqueous solution using bio-char as an adsorbent

Water Sci Technol. 2014;69(11):2265-71. doi: 10.2166/wst.2014.143.

Abstract

The characteristics of sorption of hexavalent chromium (Cr(VI)) onto bio-char derived from wood chips (spruce, pine, and fir) were evaluated as a function of pH, initial Cr(VI) concentration and bio-char dosage using synthetic wastewater in batch tests. The initial Cr(VI) concentrations were varied between 10 and 500 mg/L to investigate equilibrium, kinetics, and isotherms of the sorption process. About 100% of Cr(VI) was removed at pH 2 with initial Cr(VI) concentration of 10 mg/L using 4 g of bio-char after 5 hours of sorption reaction. The maximum sorption capacity of the bio-char was 1.717 mg/g for an initial Cr(VI) concentration of 500 mg/L after 5 hours. The sorption kinetics of total Cr onto bio-char followed the second-order kinetic model. The Langmuir isotherm model provided the best fit for total Cr sorption onto bio-char. The bio-char used is a co-product of a down draft gasifier that uses the derived syngas to produce electricity. Bio-char as a low cost adsorbent demonstrated promising results for removal of Cr(VI) from aqueous solution. The findings of this study would be useful in designing a filtration unit with bio-char in a full-scale water and wastewater treatment plant for the Cr(VI) removal from contaminated waters.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adsorption
  • Charcoal / chemistry*
  • Chromium / chemistry*
  • Hydrogen-Ion Concentration
  • Kinetics
  • Water / chemistry*
  • Water Pollutants, Chemical / chemistry*
  • Water Purification / methods

Substances

  • Water Pollutants, Chemical
  • biochar
  • Water
  • Chromium
  • Charcoal