The increasing industrial growth in several countries is placing high environmental costs despite their sustained economic development. With the enormous amount of pollution being generated, several industries have vowed to pursue prevention by taking a proactive approach towards reducing (or eliminating) pollution as part of their environmental responsibility commitment. The Kingdom of Thailand, which houses large electroplating and surface finishing facilities, is not exempted from countries contributing to the rapid spread of pollution. In fact, for these facilities, their products undergo several rinse steps which do not only generate volumes of wastes but dispose a large amount of toxic debris from acids, alkalis, heavy metals and cyanides used in pretreatment, electroplating, and post-treatment of products. However, they can take significant opportunities to ensure that their toxic debris and wastewaters have a minimum contribution towards pollution. By doing this, they can ensure environmental responsibility while ensuring their workers’ safety and being cost-effective by reducing requirements for wastewater treatment and disposal.
Copper cyanide is widely used in industries as an electrolyte in plating baths providing good adhesion of copper onto the zinc alloy substrate. However, there has been current awareness on the impact generated onto the environment and the enterprises’ workers by the wastes and toxic debris from copper cyanide. Various regulating commissions worldwide including Thailand’s Pollution Control Department have urged electroplating industries to urgently phase-out the use of copper cyanide which is considered as “highly toxic chemicals used in the plating baths lethal to a human”. Thus, there is a need to change copper cyanide into a more environment-friendly alternative.
In this study, a cyanide-free electroplating bath containing glutamate as a complexing agent is investigated as an environment-friendly alternative for copper plating. A naturally occurring non-essential amino acid, glutamate reacts with copper in aqueous solution which exhibits similar properties to copper cyanide by forming complexes1. The pH of the electroplating bath was chosen from equilibrium diagrams to avoid formation of insoluble complexes and oxides at varying copper: glutamate molar ratio. The results from the electrochemical response, determined by cyclic voltammetry, showed occurrence of one cathodic peak indicating direct reduction of copper (II)-glutamate complexes to copper metal, with 1:3 molar ratio and pH =8 exhibiting better copper deposition onto the substrate. The preliminary results suggest that copper-glutamate electroplating bath may be suitable for copper cyanide baths replacement in copper deposition without the need of additives allowing a one-step electroplating process. By carefully controlling the current flowing through the circuit, the process can deposit nanometer-thin layers of materials onto the substrate.