Chitosan-coated black sesame (Sesamum indicum L.) seed pulp as a novel candidate adsorbent for Cr(VI) elimination

Water Sci Technol. 2019 Feb;79(4):688-698. doi: 10.2166/wst.2019.085.

Abstract

This study evaluates the application of Cr(VI) adsorption from the prepared synthetic solution by black sesame (Sesamum indicum L.) seed pulp (BSSP) and chitosan (Cts)-coated black sesame seed pulp beads (Cts-BSSP). BSSP and Cts-BSSP were used as an adsorbent without any chemical or physical treatment to remove Cr(VI) from an aqueous medium. The results indicated that the Cr(VI) removal was pH-dependent and reached an optimum at pH 2.0. It has been observed that the percentage of adsorption increased from 62% to 95% when the amount of Cts-BSSP increased from 0.0125 g to 0.0250 g. The required adsorbent amount for the maximum removal was 0.05 g and 0.1 g for Cst-BSSP and BSSP, respectively. The contact time for the adsorption was 120 min and 90 min for BSSP and Cst-BSSP, respectively. Scanning electron microscopy and Fourier transform infrared spectroscopy were used to explore the possible adsorption mechanism for Cr(VI). The equilibrium data for the BSSP and Cts-BSSP were used with the Langmuir and Freundlich adsorption isotherm models to assess the adsorption capacity and relevant mechanism. The adsorption capacity of the Cts-BSSP for Cr(VI) is relatively high compared to BSSP. The monolayer maximum adsorption capacities for Cr(VI) ions were 31.44 and 18.32 mg/g for Cts-BSSP and BSSP, respectively.

MeSH terms

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

Substances

  • Water Pollutants, Chemical
  • Chromium
  • chromium hexavalent ion
  • Chitosan