Amino modification of rice straw-derived biochar for enhancing its cadmium (II) ions adsorption from water

J Hazard Mater. 2019 Nov 5:379:120783. doi: 10.1016/j.jhazmat.2019.120783. Epub 2019 Jun 17.

Abstract

To enhance the adsorption capacity of Cd2+, -NH2 groups were introduced into the rice straw-derived biochar surface by combining nitrification and amination. The batch and continuous Cd2+ adsorption experiments were performed to determine the role of -NH2 groups on the surface of biochar. The physical and chemical characteristics were analyzed for comparison. The results indicated that the adsorption capacity of the modified biochar (BC-NH2) was boosted by 72.1%. The results of continuous adsorption experiments in fixed bed columns showed that the penetration time of BC-NH2 was three times that of original biochar. The adsorption of Cd2+ by BC-NH2 is a spontaneous endothermic chemical reaction, which was obtained by combing sorption kinetics, isotherms and thermodynamic analysis. The Cd2+ adsorption was mainly the complexation between -NH2 group on biochar surface and Cd2+ in solution. Finally, a possible interaction mechanism between Cd2+ and BC-NH2 was proposed.

Keywords: -NH(2)modification; Biochar; Biomass; Cadmium (II) ions adsorption; Mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Cadmium / analysis*
  • Charcoal / chemistry*
  • Models, Theoretical
  • Nitric Acid / chemistry*
  • Oryza / chemistry*
  • Plant Stems / chemistry*
  • Porosity
  • Surface Properties
  • Water Pollutants, Chemical / analysis*

Substances

  • Water Pollutants, Chemical
  • biochar
  • Cadmium
  • Charcoal
  • Nitric Acid