Biofibre Production from Chicken Feather

Abstract

The global poultry industry generates at least 2 million tonnes of chicken feather every year. Feathers are currently hydrolysed into meal used for animal feed and fertilizer. Feather consists of 91% keratin, 1% lipid and 8% water. Raw feather also contains preen oil, offal, faecal matter and poultry processing water. Its morphology consists of barbs extending at an angle from a central hollow rachis. Impurities coat the entire feather, and particulates are trapped by layers of barbules and hooked barbicels holding adjacent barbs together. These substructures present an extensive and tortuous hydrophobic surface. Feather fibre is a multipurpose, cost effective reinforcement for polymer composites. Its incorporation in plastic, wood, concrete and cardboard makes the product lighter, insulate from heat loss and improve sound attenuation properties. The objective of this study was to develop a process to produce clean fibre recovered from chicken feather. In the treatment process, the heterogeneous characteristics of feather had to be considered. Raw feather was suspended in 25 L water in a pulper to be decontaminated using 2 stages of 0.1485% sodium hypochlorite adjusted to pH 10.0 with 1 M sodium hydroxide and cleaned in 3 stages of 0.15% hydrogen peroxide. The pulper disc impeller agitated the suspension at 10 Hz for 30 minute at each stage. Bacteriological tests confirmed pathogens such as Campylobacter, Salmonella and Enterobacteriaceae were removed during treatment. Off-white clean feathers were more than 10% whiter than dull yellow raw feather. Cleaned feather was comminuted in 300 L water using a centrifugal pump at a flow rate of 30Hz on full recycle for 4 hours. Rachis and partially cut feather were removed using a 5 mm aperture filter and fibre was recovered using a 1 mm filter. Wet fibre was dried to constant mass in an air-forced oven at 70°C. Fibre yield was 27% of feather input, or 54% of theoretical yield. Surface morphology showed no damage.