Cauliflower Leaves, an Agro waste: Characterization and its Application for the Biosorption of Copper, Chromium, Lead and Zinc from aqueous solutions

Abstract

Cauliflower leaves being non-edible, is frequently discarded from vegetable markets and it forms a part of Municipal Solid Wastes. The present study focuses on using the cauliflower leaves as a biosorbent for the removal of heavy metals Copper, Chromium, Lead and Zinc from spiked solutions of known concentrations as well as from industrial effluents using batch method. The pH, bulk density, ash content, and iodine index of the cauliflower leaves powder were calculated and further characterizations of the leaves like surface morphology and functional groups present on the surface of the biosorbent were carried out using E-SEM and FT-IR respectively. The heavy metal concentrations in the solutions were found out using ICP-AES analysis. After the biosorption process, the removal of heavy metals was found to be 80.43%, 57.26%, 99.39% and 69.91% for Copper, Chromium, Lead and Zinc respectively from spiked solution at pH 7 after adding 1% adsorbent dose at 30oC temperature for 60 minutes. The biosorption was also carried out for effluents collected from industries like powder dusting, chemical, electroplating, paper mill and textile industry and removal of all four metals were found to be in the range of 26% to 100% after biosorption process. Characterization of the biosorbent by FTIR showed the presence of various functional groups like hydroxyl, aliphatic methylene group, aromatic groups, etc. which might have involved in interacting/ binding to metal ions. The SEM images of the material showed distinct changes in the surface morphology after interacting with the metal solutions which may be due to metal stress on the biosorbent.