Potential utilisation of manganese nodule leach residue as a scavenger for cadmium from industrial effluents

This paper deals with studies on the utilisation of leached residue generated during base metal recovery form polymetallic manganese nodules of Indian Ocean, for the detoxification of industrial effluents/waste waters from cadmium for its safe disposal to the river or land. The influence of various parameters such as contact time, solution pH, and initial metal concentration in solution, temperature and adsorbent quantity, on cadmium removal were studied. The linear forms of the Langmuir and Freundlich equations were utilised for experiments with metal concentrations of 200mg/l for Cd(II) as functions of solution pH (2.0–6.0). Various rate equations were applied to study adsorption kinetics. The adsorption capacity of manganese nodule leach residue (MNLR) was found to be 19.8mg of Cd/g of residue. Under the optimised conditions cadmium level was brought down from 100ppm to nil and 200ppm to 2ppm making wastewater safe for disposal. Desorption studies were also performed to see the elution of cadmium from the loaded adsorbent from the point of view of its recycling/safe disposal with or without treatment.