title: Efficient biosorption of chromium(VI) ion by dry Araucaria leaves.
abstract: BACKGROUND
  In this paper, batch removal of hexavalent chromium from aqueous solutions by Araucaria heterophylla leaves was investigated. The batch experiments were conducted to study the adsorption of metal species and effect of different pH, contact time, metal concentration, biosorbent concentration, and adsorption capacity.
  
  
  METHODS
  Freundlich and Langmuir's isotherm model were used to describe the adsorption behavior, and the experimental results fitted Freundlich model well.
  
  
  RESULTS
  The adsorption efficiency observed for all chromium concentrations, i.e., 1, 3, 5, and 10 mg/L was 100% and the equilibrium was achieved in 30 min for 1 and 3 mg/L, whereas for 5 and 10 mg/L, it was less than 60 min. FTIR spectra was taken to identify functional groups involved in the biosorption.
  
  
  CONCLUSIONS
  Thus, Araucaria leaves can be considered as one of the cheap and efficient biosorbent for toxic hexavalent chromium removal from natural or wastewaters.
authors.affiliation: Indian Institute of Technology, Facility for Ecological and Analytical Testing (FEAT), 204 A, Southern Block, Kanpur 208016, India.
authors.forename: Dhara
authors.initials: D
authors.lastname: Shukla
authors.forename: Padma S
authors.initials: PS
authors.lastname: Vankar
mesh_terms: D000042:Absorption; D001673:Biodegradation, Environmental; D002857:Chromium / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018515:Plant Leaves / Q000378:metabolism*; D013997:Time Factors; D064028:Tracheophyta / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion