Constructed wetlands are a sanitation technology that utilize natural removal mechanisms provided by plant vegetation, substrate (soil, gravel, sand), and associated microbial populations ( Maiga et al., 2017 ; Defo et al., 2017 ).
Published in Chapter:
Kinetics of Heavy Metals Adsorption on Gravels Derived From Subsurface Flow Constructed Wetland
Celestin Defo (University of Dschang, Cameroon) and Ravinder Kaur (Indian Agricultural Research Institute, India)
Copyright: © 2020
|Pages: 21
DOI: 10.4018/978-1-7998-1871-7.ch011
Abstract
Adsorption kinetics of Ni, Cr, and Pb on gravels collected from constructed wetland was studied at varied metal concentrations and contact period for estimating the removal of heavy metals from wastewater. Batch experiments were conducted by shaking 120 ml of metal solutions having 5 concentration levels each of Ni (1.0, 2.0, 3.5, 5.0 and 6.0 mg l-1), Cr (1.0, 2.0, 3.0, 4.5 and 6.0 mg l-1), and Pb (1.0, 3.0, 6.0, 8.0 and 12.0 mg l-1) with 50 g of gravels for as function of time. Adsorption of Ni, Cr, and Pb on gravels ranged from 34.8 to 47.2, 42.7-54.9, and 47.5-56.9%, indicating their removal in the order: Pb > Cr > Ni. Freundlich model showed a good fit for Ni and Cr (R2>0.9) while Langmuir model fitted better for Pb (R2= 0.7). The pseudo-second-order model showed the best fit to simulate the adsorption rates of these metals on gravel.