Remediation of Heavy Metals in Deep-sea Mining Tailings by Using Rhamnolipid

Abstract

Objectives : Rhamnolipid for the remediation of heavy metals in deep-sea mining tailings originated from manganese nodules was mainly focused in this research. As continued development depletes land-based metal resources, deep-sea natural resources such as manganese nodules collected from the Clarion-Clipperton Fracture Zone in the Pacific Ocean are inevitably drawing attention as useful alternative resources. The London protocol 1996 (LP) under International Maritime Organization (IMO) and the International Sea-bed Authority (ISA), however, will come up with the environmental guidelines of deep-sea mining tailings by early 2020s. Accordingly, there are urgently required to develop technologies that remediate heavy metals of deep-sea mining tailings. In this research, rhamnolipids which were known as biosurfactants was used to extracting agent for heavy metals in deep-sea mining tailings.Methods : Sample (20-63 μm, manganese nodules) made of 2% (w/v) liquid using ultrapure water were stirred and mixed with a rhamnolipid solution (0.05%, 0.1%, 0.2%, 0.3%) for various elapsed time, to evaluate the possibility of remediation of heavy metals in deep-sea mining tailings using rhamnolipid. Each mixture was analyzed for heavy metals eluted into the liquid after solid-liquid separation.Results and Discussion : Rhamnolipid was effective in removal of heavy metals and environmentally friendly. The extracted concentration of copper (Cu), zinc (Zn), nickel (Ni), and cadmium (Cd) were correspondingly enhanced with specific elapsed time and rhamnolipid’s concentrations, also.Conclusions : The results of this research should be used as basic data for the actual development of the remediation technology for deep-sea mining tailings using rhamnolipid in the future.