Thermodynamic and kinetic studies of cadmium adsorption from aqueous solution onto rice husk

Abstract

-The adsorption behavior of rice husk for cadmium ions from aqueous solutions has been investigated as a function of appropriate equilibrium time, adsorbent dose, temperature, adsorbate concentrations and pH in a batch system. Studies showed that the pH of aqueous solutions affected cadmium removal with the result that removal efficiency increased with increasing solution pH. The maximum adsorption was 98.65% at solution pH 6, contact time 60 min and initial concentration of 25 mg/L. The experimental data were analysed by the Langmuir, Freundlich and Temkin models of adsorption. The characteristic parameters for each isotherm and related correlation coefficients have been determined. Δ have also been evaluated and it has been found that the sorption process was feasible, spontaneous and exothermic in nature. The kinetics of the sorption were analysed using the pseudo-first order and pseudo-second order kinetic models. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients for each kinetic model were calculated and discussed. It was shown that the adsorption of cadmium could be described by the pseudosecond order equation, suggesting that the adsorption process is presumably a chemisorption. The rice husk investigated in this study showed good potential for the removal of cadmium from aqueous solutions. The goal for this work is to develop inexpensive, highly available, effective metal ion adsorbents from natural waste as alternative to existing commercial adsorbents.

Determination of the maximum retention of cobalt by ion exchange in h-zeolites

“…Several authors have used adsorption models to describe experimental data for ion exchange in zeolites and other materials (Misak, 1995;Malekian et al, 2010;Ostroski et al, 2009;Al-Anber and Al-Anber, 2008, Silva et al, 2003, Torab-Mostaedi et al, 2010, Senthil Kumar et al, 2010. In applying such models, one should bear in mind that the ion exchange process is the most important sorption mechanism although the subsequent adsorption phenomena should not be neglected.…”

Adsorption of Manganese From Acid Mine Drainage Effluents Using Bone Char: Continuous Fixed Bed Column and Batch Desorption Studies

“…A number of alternative materials have been investigated as adsorbent for the removal of metal species from wastewaters (Giraldo and Moreno-Piraján, 2008;Kumar et al, 2010;Martins et al, 2014;Vieira et al, 2014). In this light, a promising method based on the removal of manganese using bone char as an adsorbent was recently proposed by Sicupira et al (2013).…”

Adsorption of lead and copper ions from aqueous effluents on rice husk ash in a dynamic system

“…Some of the important ones include zeolites (Wang and Peng, 2009;Okolo et al, 2000), activated carbon (Wahby et al, 2011;Moreno-Piraján et al, 2011;Attia et al, 2010;Giraldo and Moreno-Piraján, 2008), rubber ash (Mousavi et al, 2010), clay (Galindo et al, 2013;Almeida Neto et al, 2012;Vieira et al, 2010a;Vieira et al, 2010b), expanded perlite (Torab-Mostaedi et al, 2010), vermiculite (Nishikawa et al, 2012), algae (Vieira et al, 2008;Vijayaranghavan et al, 2005;Silva et al, 2003), bacteria (Yilmaz et al, 2010), coir pith (Parab et al, 2006), sugarcane bagasse (Lv et al, 2008;Gupta and Ali, 2004), olive stone (Calero et al, 2009) and rice husks Vieira et al, 2011;Senthil Kumar et al, 2010;Naiya et al, 2009;Srivastava et al, 2006;Ye et al, 2010;Nakbanpote et al, 2007;.…”