Nanostructured carboxylated-wood aerogel membrane for high-efficiency removal of Cu (II) ions from wastewater

Heavy-metal pollution is a significant environmental issue that has raised global concern due to its harmful impact on humans and the natural ecosystem. Heavy metal pollution poses several challenges in terms of remediation, including low adsorption capacity and efficiency, scale-up issues and non-degradability. Here, we developed an eco-friendly tunable dual-wavelength absorption mesoporous wood aerogel (TDWA) for removal of Cu2+ ions from wastewater based on wood nanotechnology and carboxylated functionalization treatment. Nanostructured pores generated from the cell walls with carboxyl groups due to the removal of most lignin/hemicellulose and 2,2,6,6-tetramethylpiperidine oxidation. Mechanical compression was parallelly applied to the transverse direction of TDWA resulted in removing micron-scale cell cavity and intercellular, which significantly improved the dynamic adsorption performance with an excellent Cu2+ adsorption capacity of 115 mg g−1. This value is superior to most wood-based adsorption membrane as wastewater mainly flowed through the continuous microfibril network in the cell wall. The double-layer mesoporous TDWA membrane (5 mm) possessed a favorable removal efficiency (99.83 %) even after 5-cyclic adsorption (92.34 %). The invented nanostructured TDWA membrane in the current study has promising potential to substitute the present plastic-based membrane in the realistic Cu2+ adsorption because of the facile technology, renewability and high removal efficient, as well as the complete biodegradability.