Biodegradation of Three Cellulosic Fabrics in Soil

The cellulosic fabrics cotton, rayon, and Tencel® are commonly used in the textile industry (Kroschwitz, 1990). The chemical composition of the fabrics is similar, but they differ in the arrangement of the cellulose polymers in the fabrics (Collier and Tortora, 2001). The basic polymer for all cellulosic fibers consists of repeating glucose units. For the cotton fabric, the cellulosic polymers within the cotton fibers have a high degree of polymerization (approximately 6,000 to 10,000 units), highly reactive hydroxyl (-OH) groups, and the ability to support hydrogen bonding with the 70% crystalline area. The remaining 30% of the fiber is amorphous. Like cotton, rayon is composed of cellulose, but the cellulose chains in rayon are shorter with the degree of polymerization being between 400 to 700 units. Thus, about 30% of the cellulose is crystalline with 70% being amorphous. Tencel® lyocell (generic classification) is a highly crystalline fiber with high strength capacity. In 2007, over 9 Tg (10 million tons) of textile waste went into landfills in the U.S. (U.S. EPA, 2008). The anaerobic conditions found in landfills result in slow biodegradation rates of cellulosic materials. To divert fabric waste from landfills, an alternative method of fabric disposal would be application of cellulosic fabric waste to surface soil where aerobic conditions could result in enhanced biodegradation rates. Information on cellulosic fabric biodegradation rates in surface soil would also be valuable in providing estimates of the length of time that fabrics have been buried in soil, contributing useful data to forensic investigations (Janaway, 2008). The objective of this field study was to determine the biodegradation rates of 100% rayon, cotton, and Tencel® woven fabrics buried in an aerobic Captina silt loam soil.