Efficacy improvement technique of air-filtration unit affected by biofouling using electroless Ni-Cu-P coating

Abstract

Moisture from ar is often responsible for biofouling and corrosion on the inner walls of the air filtration system and there by affecting the bacteria colony forming units (CFU Count). This phenomenon is more prevalent in humid environment. Applying electroless Nickel-Copper-Phosphorous (Ni-Cu-P) coating on mild steel helps to prevent bio fouling. An air filtration unit with inner walls coated with nano-TiO₂ and inlet filter mesh made of Luffa and coated activated charcoal and zeolite is used in the experimentation process. The inner chamber is also radiated by band C of Ultraviolet sources (UVC) with 254 nm wavelength. A sudden spike in bacteria colony count has been observed as the air filtration unit remains in off mode for prolonged duration of time. The efficacy of the air filtration unit upon remaining in off- mode for a long time has been determined in the present work considering the bacterial colony count as response. Electroless Ni-Cu-P coating has been applied at selected locations previously affected by biofouling. A predictive model has been developed following response surface methodology using bacterial colony count as response and the composition of the electroless coating bath as the process parameters.  Genetic algorithm was applied for the determination of the best possible constitution of chemical coating bath for the minimization of the bacterial colony count. Bacteria Colony formation was significantly affected by the sources of Nickel ion, Copper ion and the concentration of reducing agent in the electroless Ni-Cu-P coating bath. The confirmation run showed that the observed CFU count at the optimum condition converges with the data obtained from Genetic Algorithm.