Hybrid Powder-Based Additive Manufacturing of Laser-Induced Graphene 3D Architectures with Tunable Porous Microstructures from Waste Sources of Black Liquor and White Pollution

Macroscopic 3D-controllable graphene (3D-CG) architectures not only retain the intrinsic properties of graphene sheets but also exhibit structural advantages for pollutant adsorption and energy storage. This paper proposes a novel hybrid powder-based additive manufacturing method to fabricate 3D biomass-derived laser-induced graphene (3D B-LIG) structures with customizable geometries and microporous features. This method utilizes two waste sources as feedstock precursors for sustainable graphene production: “black liquor” (sodium lignosulfonate, NaLS) and “white pollution” (polypropylene, PP). Employing a computer-aided design process, this method allows for the synchronous creation of various freeform macrostructures, with either identical or variable sections. To optimize the formability and processing efficiency of 3D B-LIG, systematic studies have been conducted. These studies establish the relationship between processing parameters and the resulting structures by controlling the laser parameters and the mixing ratio of NaLS and PP. By leveraging tunable microporous structures with a maximized specific surface area of 485.3 m² g⁻¹, 3D B-LIG demonstrates exceptional performance in pollutant adsorption (with a maximum adsorption capacity of 283.3 mg g⁻¹ for methylene blue) and energy storage (with a gravimetric specific capacitance value of 194.9 F g⁻¹).