Engineering MOF-Enhanced 3D-Printed Monoliths for Scalable and Sustainable Water Filtration Solutions: Tackling Contaminant Leaching and Adsorption

Abstract

Clean water, a basic requirement for the existence of life, is inaccessible to millions of people all around the world due to serious challenges like water pollution. Conventional methods of water purification are often unable to eliminate micro-sized and soluble contaminants, hence innovative approaches involving nanomaterials can be investigated for more successful solutions. Metal-organic frameworks (MOFs) offer a promising alternative for water filtration that can absorb pollutants due to its abandoned and well-structured nano-porosity built within its structure. However, secondary contamination from leached MOF materials remains a concern. In this paper, we propose the design and manufacturing of MOF laden monolith 3D structure (MLMS). To achieve the MLMS, extrusion-based additive manufacturing is used to construct the host structure with macro-scale porosity using the Moire pattern. Copper-based MOF (Cu-MOF) is grown and conditioned on the host with proper adhesion force that can minimize leaching while absorbing pollutants demonstrating the functionality of MLMS. Cu-MOF growth, distribution, and leaching rate have been studied using commonly available 3D printing materials (PLA, PETG, ABS, and TPU) which show about 12.8%-75.8% MOF coverage with various numbers of MOF synthesis cycles. Additionally, 16.1% leaching from the host has been measured at a high flux (4144.40 L m-2 h-1) water flux, which demonstrates better adhesion characteristics between the host and MOF particles. The adsorption efficiency of malachite green dye has been studied for the MLMS which shows 94.77% and 36.42 % removal efficiency from steady and flowing (1184.12L m-2 hr-1) conditions, respectively.