The Box-Behnken design is an example of a response surface methodology employed to optimize a process in this case, the leaching of Cu from PCB pieces . The choice of malonic acid and H2O2 for this study stems from the fact that with regards to the product of their degradation, these reagents are greener and biodegradable alternatives to the popular mineral acid leachants including HCl, HNO3, and aqua regia .