Effect of lignocellulosic fiber composition on the aquatic biodegradation of wood pulps and the isolated cellulose, hemicellulose and lignin components: kinetic modelling of the biodegradation process

The importance of renewable and environmentally friendly wood pulp fibers as an input material for single-use products has grown significantly. However, discarded single-use materials are found in the environment as litter and are sometimes disposed of in wastewater. It is important that these materials are biodegradable and environmentally benign. Wood pulp is mainly comprised of lignocellulosic material, and its composition and structure can vary depending on raw materials and processing, ultimately impacting the biodegradability. In this research, the aquatic biodegradation of five kinds of wood pulp and six different samples of isolated lignocellulosic components (cellulose, hemicellulose, and lignin) have been explored in a consistent detailed manner for the first time, and the effects of chemical composition on the biodegradation discussed. Several lignocellulosic materials were characterized using compositional analysis and were subjected to aquatic biodegradation with bio-solids from a wastewater treatment plant as an inoculum to indicate the potential to biodegrade in the environment. Cellulose and hemicellulose were readily biodegraded over a course of one month. The lignin samples were not biodegradable under these conditions, and the lignin within fibers decreased the biodegradability of the other components of the lignocellulosic fibers. It was also determined that ash and extractives negatively affect the biodegradability. The aerobic aquatic biodegradation results are useful for product designers to select different lignocellulosic materials for applications and for environmental scientists to understand the fate of these fibers in the environment.