Kinetic modelling of cadmium and lead removal by aquatic mosses

Abstract

-Because biosorption is a low cost and effective method for treating metal-bearing wastewaters, understanding the process kinetics is relevant for design purposes. In the present study, the performance of the aquatic moss Fontinalis antipyretica for removing cadmium and lead from simulated wastewaters has been evaluated. Five kinetic models (first-order, pseudo-first-order, Elovich, modified Ritchie second-order and pseudo-second-order) were fitted to the experimental data and compared. Previously, the effect of parameters such as the initial solution pH, contact time, and initial metal ion concentration on biosorption was investigated. The initial pH of the solution was found to have an optimum value in the range of 4.0-6.0. The equilibrium sorption capacity of cadmium and lead by Fontinalis antipyretica increased with the initial metal concentration. For an initial metal concentration of 10 mg L -1 , the uptake capacity of the moss, at equilibrium, is the same for both metals (4.8 mg g -1 ). Nevertheless, when the initial concentration increases up to 100 mg L -1 , the uptake of Pb(II) was higher than 78%. The pseudo-second order biosorption kinetics provided the better correlation with the experimental data 2 ( 0.999) ≥ R .

STUDY OF BINARY AND SINGLE BIOSORPTION BY THE FLOATING AQUATIC MACROPHYTE Salvinia natans

“…From fixed-bed experiments, the breakthrough curves showed that H. verticillata was capable of decreasing Cd , pH 6.0), respectively. Martins et al (2014) studied the performance of the aquatic moss Fontinalis antipyretica for removing cadmium and lead from simulated wastewaters. The authors found that, for an initial metal concentration of 10 mg.L -1 , the uptake capacity of the moss, at equilibrium, was the same for both metals (4.8 mg.g , the uptake of Pb (II) was higher than 78%.…”

Fabrication of Cellulose-Based Chitosan Coating Adsorbents for Capture to Cadmium (Ii) and Zinc (Ii)

“…As a result, the adsorption ability of CCCF was mainly obeyed to saturation mechanisum to chitosan layer on the surface. Also as seen in Table 2 for the results of sorption kinetics [12] the fitting with Freundlich kinetics was higher than that of Langmuir one, indicating that the adsorption mechanism of CF and ODCF hadthe high correlation coefficient(r 2 = 0.993, 0.997, 0.998 for CF, ODCF and CCCF, respectively). It was apparent that the pseudo second-order model was considered , since the both samples of ODCF and CCCF were compatible with the pseudo second-order model (r 2 = 0.999 for ODCF, and r 2 = 0, 986 for CCCF).…”

Kinetics of nickel bioaccumulation and its relevance to selected cellular processes in leaves of Elodea canadensis during short-term exposure

“…In particular, the passive sorption of Ni by bael tree (Aegle marmelos) leaf powder (Kumar and Kirthika 2009) and Cassia fistula biomass (Hanif et al 2007) has been described by pseudo-second-order kinetics. Recently, this model has been applied to simulate Cd and Pb removal from artificial wastewater by the living aquatic moss Fontinalis antipyretica (Martins et al 2014). The applicability of second-order kinetics to Ni uptake by Elodea leaves during the first 8 h of exposure to metal suggests that the passive binding of metal ions (chemisorption) is a rate-limiting step at the initial phase of Ni accumulation.…”