Enhancement of water absorption properties of date palm fibers-based composites via alkaline treatment

Abstract

This study examined the ability of a biodegradable composite material to absorb water. The composites were created by combining a matrix of polylactic acid (PLA) with date palm wood fibers (DPWF) for reinforcement. Before incorporating the fibers into the polymer, they underwent chemical treatment using alkali solutions of NaOH and KOH. This treatment aimed to modify the surface properties of the natural fibers and enhance their water absorption capabilities. Different composites were fabricated, including PLA combined with untreated fibers (PLAUF), and PLA with treated fibers using both NaOH and KOH (PLAF-NaOH and PLAF-KOH), with varying weight percentages of fibers ranging from 0 to 40%. To evaluate the water absorption capability of the composites, water retention tests were conducted at room temperature (cold) and 50 °C (hot) for 24, 48 h and until the absorption reached equilibrium. The results demonstrated a significant enhancement in water retention, particularly in the case of the NaOH-treated samples, which exhibited approximately a tenfold increase in water retention compared to untreated samples. For example, the 20 wt% NaOH treated filler had a hot-water retention of 20%, compared to 2% for the untreated filler. Additionally, a higher percentage of filler resulted in a higher rate of water absorption. The 40 wt% NaOH treated sample with 20% water retention, absorbed 10 times more than the 10 wt% NaOH treated filler, with only 2% water retention. The developed composites have potential applications in natural gas dehydration processes, offering an alternative to the energy-intensive and environmentally harmful glycol-based dehydration methods currently in use.