Analysis of Cadmium Adsorption on Novel Organo-Ceramic Adsorbents with a Thiol Functionality

Abstract

The adsorption characteristics of cadmium ions from aqueous solutions onto two organo-ceramic adsorbents synthesized in our laboratories were studied. The main species participating in the adsorption process, determined from the chemical equilibrium, is Cd 2+ . Formation of a bidentate cadmium-thiol complex is proposed to explain the experimental isotherms. The kinetics of adsorption onto the sol-gel-synthesized adsorbent was studied in a differential batch reactor with recycle. Two kinetic models were tested with experimental data: chemical reaction and film/pore mass-transfer resistances. The results indicate that either model can be used to explain the adsorption process as observed from the AARD values and from the F-test. The values of fitted parameters are k 1 ) 0.0021 L‚g/mmol 2 ‚min, D p ) 1.4 × 10 -7 cm 2 /s, and τ ) 5.0. The last two parameters can be used to satisfactorily predict the breakthrough curve in a fixed bed by the film/pore diffusion model. A sensitivity analysis shows that pore diffusion resistances control the adsorption process.

Removal of cadmium and nickel from aqueous solution using expanded perlite

“…The chronic toxicity of nickel to humans and the environment is also well-known and high nickel concentrations cause gastrointestinal irritation and lung and bone cancers. In recent years, various adsorbents have been used for removal of Cd (II) and Ni (II) from aqueous solution (Benguella and Benaissa, 2002;Gomez-Salazar et al, 2003;Gupta et al, 2003;Singh et al, 2005;Nwabanne and Ibbokwe, 2008). However, new adsorbents with local availability, high adsorption capacity and composed of economical materials are still needed.…”

Kinetics and equilibrium adsorption of Cu(II), Cd(II), and Ni(II) ions by chitosan functionalized with 2[-bis-(pyridylmethyl)aminomethyl]-4-methyl-6-formylphenol

“…The main techniques that have been used on metal content reduction from industrial waste are chemical precipitation, ion exchange, membrane filtration, electrolytic methods, reverse osmosis, solvent extraction, and adsorption [3,[8][9][10][11]. However, these methods are limited by high operational cost and/or may also be inefficient in the removal of some toxic metal ions, mainly at trace level concentrations [2,12].…”

Pyrazole functionalized organo‐ceramic hybrids for noble metal separations

“…Details of the computational technique can be found elsewhere. 24 This pore diffusion model represents the experimental breakthrough curve for its slope and the breakthrough capacity (C/C 0 ϭ 1.0) well by using the diffusivity (D M ) of Pd(II) chloride and the tortuosity () of the adsorbent from the batch kinetics modeling (Figure 8). The calculated capacities for Pd(II) chloride are 1.27, 1.30, and 1.30 mmol/g by the breakthrough experiment, by the pore diffusion model, and by the adsorption isotherm (Eq.…”