Title: Kinetics of adsorption of pollutants removal from mine wastewater by a coal fly ash-based coagulant

Authors: M. Clotilde Apua

Addresses: School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, P/Bag 3, Wits 2050, South Africa

Abstract: This work discusses the results of experimental investigation on the study of coagulation's adsorption aspect for removing toxic ions from mine wastewater using fly ash-based coagulant. The studied mine wastewater was susceptible to the coagulation process. The important part of this research was to analyse the mechanism of the pollutant coagulation process using a fly ash-based coagulant. Several kinetic models were used to test the coagulation data and to examine the mechanism controlling coagulation adsorption. The present results of pollutant removal well-fit pseudo-second-order model. Film diffusion and intraparticle diffusion were involved in the process. The intraparticle diffusion coefficients for the different pollutants were calculated from Weber-Morris and Boyd's models; the results showed that the intraparticle diffusion coefficients for the specific pollutants range from 1.8 10^-11 to 0.57 10^-13 cm²/sec and 1.05 10^-12 to 1.87 10^-12 cm²/sec, respectively (except for Ni and Ca for the Weber-Morris model).

Keywords: adsorption kinetics; coagulation; coal fly ash-based complex coagulant; hydroxide precipitate; toxic ions.

DOI: 10.1504/IJEE.2025.143560

International Journal of Environmental Engineering, 2025 Vol.13 No.1, pp.57 - 91

Received: 10 Feb 2024
Accepted: 03 Jun 2024
Published online: 30 Dec 2024 *