Sustainable development of lignin-based biodegradable coating from palm tree waste for aluminum foil applications

Abstract

Abstract The environmental challenges presented by synthetic, non-biodegradable coatings used in aluminum packaging have accelerated the search for sustainable alternatives. This research aimed to develop and optimize biodegradable lignin-based coatings derived from Date Palm Empty Fruit Bunches (DPEFB)-an abundant agricultural waste in Oman offering an eco-friendly solution that supports sustainable packaging and waste management. Five key objectives guided this work: (1) extract and purify lignin using environmentally friendly alkali treatment; (2) develop and optimize a lignin-based coating formulation to improve barrier performance; (3) apply the coating using scalable techniques such as dip-coating (with potential for roll- or spray-coating); (4) evaluate mechanical, thermal, and barrier properties; and (5) assess the environmental and economic feasibility of replacing synthetic coatings. The lignin extraction process yielded 24.92% purified lignin, confirmed through FTIR analysis (aromatic peaks at ~ 1510 cm⁻¹) and TGA, indicating thermal stability up to 250°C. The coating demonstrated strong adhesion and a 30% reduction in oxygen transmission rate (OTR), along with significantly improved water vapor resistance. SEM imaging verified uniform surface coverage with minimal defects. Economically, the proposed coating offers a 22–28% cost reduction compared to synthetic alternatives. With Oman generating over 3,000 tons of DPEFB annually, this research highlights a valuable pathway for waste valorization. A projected ROI of 1.6 within the first year of semi-industrial implementation confirms its commercial viability. This study presents a scalable, low-cost, and sustainable coating technology aligned with Oman Vision 2040, contributing to environmental protection, industrial innovation, and circular economy goals. It fills a critical gap in the development of biodegradable packaging materials using locally sourced biomass.