Carboxylated nanocellulose superabsorbent: biodegradation and soil water retention properties

In this study, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)-oxidized nanocellulose superabsorbents are prepared using three different drying techniques: freeze-dried, and oven-dried at low and high temperatures. The benefits are investigated by evaluating the superabsorbent structure, composition and application rate. The absorption performance of nanocellulose superabsorbents is affected by the concentration and type of salts in the soil water extracts. Oven-dried at 50°C SAP presents the highest ionic sensitivity attributed to its large number of accessible carboxylate groups. The water retention of the soil treatments increases with increasing application rate. Soil treated with the freeze-dried superabsorbent shows the highest water retention, whereas those amended with the 50°C oven-dried SAP remain moist the longest. The biodegradation rate of these materials depends on the application rate and nutrient availability. Carboxylated nanocellulose superabsorbents emerge as high-performance biodegradable materials for agricultural use, able to replace the current non-biodegradable petrochemical-based superabsorbents.