3D printed superelastic, pores-aligned, and anti-swelling lignocellulose/chitosan composite aerogels for sustainable gold recovery

Conventional aerogel adsorbents for gold recovery from electronic waste (e-waste) face critical limitations, including uncontrollable structure and brittle mechanical properties. This study explores a hierarchically pores-programmable aerogel derived entirely from bio-mass using Direct Ink Writing (DIW) 3D printing method with the aid of directional freezing treatment for building aligned and high resolution (80 μm) printed structures. The ink is for-mulated from a synergistic combination of three natural components: lignocellulose (LCNF), betaine (B), and carboxylated chitosan (C). The resulting LCNF-0.4B-0.2 C aerogel exhibits a highly ordered vertical porous structure, and excellent mechanical resilience, maintaining over 90% compression recovery after 10 compression cycles. This aerogel demonstrates high adsorption capacity and excellent selectivity for Au (III), reaching up to 1357.8 mg/g. The adsorption ef-ficiency of LCNF-0.4B-0.2 C aerogel remains above 80% after eight adsorption-desorption cycles. A proof-of-concept application is conducted by retrieving gold from real cellphone motherboards, which validates the desirable performance of proposed aerogel. This work provides a novel strategy for the design and manufacture of high-performance and environmentally benign ad-sorbents for gold recovery from e-waste.