Abstract
Bio-based adsorbents from grape pomace used in waste water clean-up activities are demonstrated in the present study. An application of thermal treatment to the oven dried and grinded grape pomace resulted in the development of a porous carbonaceous biosorbent having selective surface sites favourable for binding of metal ion adsorbates. While the electrostatic nature of adsorbent-adsorbate interactions were indicative from pH and FTIR studies, "Weber and Moris" plots helped to estimate the nature of the adsorbate transfer process which is interplay of film and particle diffusion. The maximum adsorption capacity was determined from Langmuir plot and reveals the higher uptake of Pb2+ in comparison to Cd2+. The relationship of the divalent cationic properties of the selected adsorbates in aqueous media is reflected. Effect of various operating parameters along with equilibrium, kinetic and thermodynamic studies reveal the efficacy of the GPMAC with an adsorption capacity comparable to other reported adsorbents. The developed adsorbent was tested under a real metal fabricating industrial effluent where despite the presence of competing pollutants and a high COD, greater than 89% metal removals was achieved. Also high regeneration capacity of GPMAC for reuse has established the practicality of the developed system. The experimental results reveal that the winery wastes have the potential for cost effective and eco-friendly wastewater treatment. Also, developing an effective, low cost adsorbent from winery solid waste like grape pomace is a new promising strategy and sustainable solution towards its efficient waste valorisation. (C) 2016 Elsevier Ltd. All rights reserved.