Cadmium uptake by algal biomass in batch and continuous (CSTR and packed bed column) adsorbers

Abstract

a b s t r a c tIn this work, the properties of marine algae Gelidium, algal waste from agar extraction industry and a composite material were investigated for cadmium(II) biosorption. Equilibrium experiments were performed at three pH values (4, 5.3 and 6.5). Equilibrium data were well described by the Langmuir and Langmuir-Freundlich isotherms. Two models predicting the pH influence in the cadmium biosorption (discrete and continuous models) have been developed in order to better describe the equilibrium. The continuous model also considers a heterogeneous distribution of carboxylic groups, determined by potentiometric titration. The results of batch kinetic experiments performed at different pH values were well fitted by two mass transfer models and the homogeneous diffusion coefficients for the cadmium ions inside the biosorbent were obtained. Continuous stirred tank reactor (CSTR) and packed bed column configurations were also examined for the biosorption of cadmium ions. A strong acid (0.1 M HNO 3 ) was used as eluant to regenerate the biosorbents in the column. Several mass transfer models were applied with success to describe the biosorption process in batch mode, CSTR and fixed bed column.

Effect of the pH and temperature on the biosorption of lead(II) and cadmium(II) by sodium-modified stalk sponge of Zea mays

“…Cd(II) has conserved chemical speciation until pH 8, however, the biosorption of this metal decreased at pH values up to 5. This behavior was also observed by Vilar et al (2008) using algal biomass. Maximum uptake by the sodium modified stalk sponge of Z. mays of 90% was observed for both Pb(II) and Cd(II) at pH 5.…”

Biosorptive Abatement of Cd2+ by Water Using Immobilized Biomass of Arthrobacter sp.: Response Surface Methodological Approach

“…It is simple to operate and can be scaled-up from a laboratory process. Few attempts have been made for the removal of cadmium from water using continuous mode. , The use of bacteria in this area of biosorption is advantageous . However, the use of microbial biomass in its native form for large-scale process utilization is not practicable because of its smaller particle size, poor mechanical strength, and little rigidity.…”

Sorption of copper by a highly mineralized peat in batch and packed‐bed systems

“…In order to include the pH dependence in the sorption modelling, an equilibrium model assuming one type of active sites for metal adsorption and competition between metal ions and proton, based on apparent equilibrium binding constants K H and K M for proton and metal, respectively, has been applied. 5 The batch equilibrium model is represented by the expression:…”