Cadmium extraction from the electrodeposition waste generated in CdS/CdTe solar cell fabrication

On-site chemical waste management is an essential field to be addressed by researchers to avoid unsystematic chemical waste disposal to the environment, which triggers severe damages to natural habitats and living beings. Though, the waste generated in CdS/CdTe based solar cell manufacture may contain toxic levels of Cd heavy metal, Cd in photovoltaics was not reported to leach out during power generation. This study proposed the electroplating technique as an effective method to extract cadmium from the electrolyte waste generated in CdS/CdTe solar cells fabrication by wet methods. The galvanostatic extraction was performed by applying a constant 0.2 A current at a potential lower than 5 V for 23 h. Removal of 98% cadmium in the waste solution was achieved and further confirmed by the AAS analysis. The EDX, XRF, and XRD analysis confirmed the presence of pure cadmium and cadmium as a mixture of hexagonal-Cd, hexagonal-Cd(OH)_2, monoclinic-Cd(OH)₂, cubic-CdTe, and cubic-CdO in the materials extracted.