Influence of pH and ionic strength on Cu(II) biosorption by aerobic granular sludge and biosorption mechanism

Abstract

BACKGROUND: To elucidate the process and mechanism of Cu(II) biosorption onto aerobic granules, the influence of pH and ionic strength (IS) on the Cu(II) biosorption capacity and biosorption mechanism was studied.

Characteristics and mechanisms of Cu(II) biosorption by disintegrated aerobic granules

“…Moreover, it is noticeable that the rate of Cu(II) uptake was very rapid in the first 10 min. This rapid initial biosorption was consistent with the results reported by Gai et al [24] in which the time required for equilibrium was 30 min at an initial Cu(II) concentration of 125 mg/L. It also can be seen from Fig.…”

“…While Gai et al [24] reported that, the maximum adsorption capacity was 39.84 mg/g SS at 250 mg/L of Cu(II) for integration aerobic granules (IAG). The compared results demonstrated that DAG could be used as an effective adsorbent to remove Cu(II) probably due to its larger specific surface area.…”

Recovery of uranyl from aqueous solutions using amidoximated polyacrylonitrile/exfoliated Na-montmorillonite composite

“…This phenomenon is indicative of a chemical chelation mechanism rather than ion-exchange process. Some researchers [12,32] also found this tendency. According to the colloidal chemistry theory and DLVO theory, the adsorbent is surrounded by an electrical double layer, thus subjected to the double layer repulsion force and Van der Waals attraction force, maintaining equilibrium within a certain distance.…”

Interaction between Heavy Metals and Aerobic Granules

“…For example, the biosorption capacities of aerobic granules increased from ~20 mg Pb 2+ /g to 44 mg Pb 2+ /g when the solution pH was increased from 3.0 to 4.0 (Yao et al, 2008). Cu (II) adsorbed by aerobic granules at pH 3 was 19.25 mg/g and that at pH 5 was 36.72 mg/g (Gai et al, 2008). It is believed that the biomass surface is protonized at low pH.…”

“…The protonized ligands and metal cations will compete for binding sites. As the pH increases, more functional groups with negative charges become exposed, which results in the biosorption capacity enhancement (Gai et al, 2008;Hawari & Mulligan et al, 2006a). Higher temperature always favors the adsorption process through the increase in surface activity and kinetic energy of the solute (Sag & Kutsal, 2000).…”