Re ECF Project: 2011-12

Project Title: Selective adsorption and removal of toxic metals in seawater

Applicant: Prof. YEUNG King-lun of The Hong Kong University of Science & Technology

Total Approved Grant: $489,000 (ECF & WWGF: 50/50)

Duration: 1/12/ 2011 to 31/5/2013

Project Status/Remarks: Completed

Scope:
The project aims to develop an effective technology for the removal and treatment of heavy metal pollutions in seawater through adsorption by salt-tolerant, fouling-resistant adsorbents that are designed to selectively remove a target pollutant or class of pollutants from contaminated seawater.

Summary of the Findings/Outcomes:
Selective adsorbents were prepared and investigated. New methods for synthesis, characterization and testing of the adsorbents were established and used. Adsorbents containing amino moieties were identified to be excellent for adsorption of heavy metal cations including copper, cadmium and zinc, while Fe3+-modified amino-grafted adsorbents are good for removal of chromium, antimony and arsenic that exist as oxyanions in seawater. Procedures for preparing these amino-grafted and Fe3+-modified amino-grafted adsorbents were successfully applied to magnetic adsorbents. The magnetic adsorbents were shown to retain their magnetic properties after metal adsorption from seawater. Experiments were carried out to determine the adsorption rates, equilibrium and mechanism as a necessary step towards material and process optimization for heavy metal removal from seawater. Treatment of heavy metals contaminated seawater was investigated in a packed-bed adsorption column and a HGMS/magnetic adsorbent unit. The results indicated comparable performance with the packed-bed adsorption column being more suitable for treating point source pollution, and the HGMS/magnetic adsorbent being more appropriate for treating non-point source pollution.