Chromium(VI) sorption efficiency of acid-activated banana peel over organo-montmorillonite in aqueous solutions

Anam Ashraf, Irshad Bibi, Nabeel Khan Niazi, Yong Sik Ok, Ghulam Murtaza, Muhammad Shahid, Anitha Kunhikrishnan, Dongwei Li, Tariq Mahmood

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

In the present study, we examined sorption of chromate (Cr(VI)) to acid-activated banana peel (AABP) and organo-montmorillonite (O-mont) as a function of pH, initial Cr(VI) concentration at a sorbent dose of 4 g L-1 and at 20 ± 1°C in aqueous solutions. In sorption edge experiments, maximum Cr(VI) removal was obtained at pH 3 after 2 hours by AABP and O-mont (88% and 69%). Sorption isotherm data showed that the sorption capacity of AABP was higher than O-mont (15.1 vs. 6.67 mg g-1, respectively, at pH 4). Freundlich and Langmuir models provided the best fits to describe Cr(VI) sorption onto AABP (R2 = 0.97) and O-mont (R2 = 0.96). Fourier transform infrared spectroscopy elucidated that for AABP mainly the –OH, –COOH, –NH2, and for O-mont intercalated amines and –OH surface functional groups were involved in Cr(VI) sorption. The scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM-EDX) analyses, although partly, indicate that the (wt. %) proportion of cations (e.g., Ca, Mg) in AABP decreased after Cr(VI) sorption. This may be due to ion exchange of chromite (Cr(III)) (produced from Cr(VI) reduction) with cationic elements in AABP. Also, Cr(VI) desorption (using phosphate solution) from AABP was lower (29%) than that from O-mont (51%) up to the third regeneration cycle. This bench scale comparative study highlights that the utilization of widely available and low-cost acid-activated biomaterials has a greater potential than organo-clays for Cr(VI) removal in aqueous media. However, future studies are warranted to precisely delineate different mechanisms of Cr(VI) sorption/reduction by acid-activated biomaterials and organo-clays.

Original languageEnglish
Pages (from-to)605-613
Number of pages9
JournalInternational Journal of Phytoremediation
Volume19
Issue number7
DOIs
Publication statusPublished - 2017 Jul 3
Externally publishedYes

Keywords

  • Biosorption
  • Contaminated water
  • FTIR
  • Modeling
  • Organo-clays
  • Remediation

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution
  • Plant Science

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