Investigation of film formation in water-distribution systems by field emission sem and spectroscopy techniques
EPA has set limits on the concentration of heavy metals in drinking water supplies to protect the public health. Furthermore, the failure of pipes in the water distribution system from corrosion represents a massive investment in rebuilding its infrastructure. We have initiated a program to study the formation of corrosion-inhibition films formed in potable water delivery systems using various chemical phosphate treatments. In particular, blends of ortho- and polyphosphates have recently been used to reduce both lead and copper leaching. Several factors are important to the successful implementation of the phosphate technologies, including film thickness and porosity, rate and stability of formation and water quality conditions. In an attempt to understand the performance of these phosphate blends, advanced analytical techniques have been employed to study the nucleation and growth mechanisms of the passivation films in a variety of water systems. We report here some preliminary results on the study of the film formation by field emission scanning electron microscopy (FESEM) technique.