Aerobic granules: a novel zinc biosorbent

Aims: Aerobic granules are aggregates with a compact and porous microbial structure. In view of the potential use of aerobic granules as biosorbents for Zn(II) removal from industrial wastewater, this study investigated the effects of initial Zn( II) and aerobic granule concentrations on the kinetics of Zn(II) biosorption on the aerobic granule surface. Methods and Results: Acetate-fed aerobic granules with a mean diameter of 1.0 mm were used as biosorbents. Results showed that the kinetics of Zn(II) biosorption on the aerobic granule surface were related to both initial Zn(II) and granule concentrations. It was found that the real driving force for Zn(II) biosorption on the aerobic granule surface could be described by the ratio of initial Zn(II) concentration (C-o) to initial granule concentration (X-o), rather than individual C-o or X-o. The C-o/X-o ratio provides a unified basis for interpretation of the biosorption data obtained under different initial conditions. The maximum biosorption capacity of Zn(II) by aerobic granules was 270 mg g(-1). Conclusions: It appears that the aerobic granule can be used as an effective biosorbent for efficient removal of Zn(II) or other types of heavy metals from industrial wastewater. Significance and Impact of the Study: This study could lead to the development of a novel granular biosorbent for the removal of heavy metals from wastewater. A simple and compact aerobic granule-based biosorber could be expected.