What is it about?
Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m3 of copper and 1.35 kg/m3 of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide give dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100-500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with > 99 % efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process.
Why is it important?
From the Indium-Tin-Oxide etching wastewater, copper nanopowder was synthesized. Solution chemistry of ITO etching wastewater is addressed. A techno-economical feasible, environment friendly and occupational safe process. Brings back the material to production stream and address the circular economy. A cradle to cradle technology management, which lowers the futuristic carbon economy
The following have contributed to this page: Dr Basudev Swain