Title: Comparative evaluation of nickel ions removal from aqueous solutions using hydrochar and biochar of cypress cones

Authors: Mahboub Saffari; Masomeh Moazallahi

Addresses: Department of Environment, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran ' Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran

Abstract: A Box-Behnken design (BBD) under response surface methodology (RSM) was used to optimise the nickel (Ni) ions removal by biochar and hydrochar of cypress cones from aqueous solutions. As result, the Ni removal in hydrochar (average 42.14%) was almost twice that of biochar (average 23.23%), which can be attributed to the higher porosity and the existence of oxygenated functional groups in hydrochar than biochar. The optimisation results of RSM showed the high ability and accuracy of this model (R² > 0.96) in estimating Ni removal. The numerical optimisation result predicted the most removal of Ni by biochar (51%-57%) and hydrochar (67%-69%), with desirability 1. In general, despite the lower production cost and removal of higher amounts of Ni by hydrochar compared to biochar, but it seems that due to the wood structure of hydrochar, the application of modification methods (physico-chemical activation) may be necessary to help remove more Ni.

Keywords: adsorption; biochar; hydrochar; nickel; optimisation.

DOI: 10.1504/IJGW.2022.124201

International Journal of Global Warming, 2022 Vol.27 No.3, pp.247 - 270

Received: 27 Aug 2021
Accepted: 01 Dec 2021
Published online: 18 Jul 2022 *

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