Simple Fabrication of Copper Nanoparticle-Loaded Biochar from Rosemary Extraction Residues for Peroxydisulfate Activation Towards Ponceau 4R Decolorization

Abstract

Rosemary extraction residues (RERs) are unused biomass released from the supercritical CO2 extraction of rosemary essential oil. To reduce waste, RERs were used for the simple preparation of copper nanoparticle-loaded biochar (CuNPs/BC). One-pot pyrolysis of cupric acetate-impregnated RERs created zero-valent copper nanoparticles (CuNPs) with an average particle size of 15 ± 2 nm within the biochar (BC) matrix. Accordingly, the CuNPs/BC nanocomposite was applied for peroxydisulfate (PDS) activation in Ponceau 4R (P4R) decolorization. At 25 oC, pH 6.0, and 2.00 mM PDS, 1.00 g/L CuNPs/BC decolorized 99.3% P4R (20 ppm) after 120 min. Additionally, P4R decolorization was effective in a broad range of initial pH values (3.0–9.0). Altogether, RER-derived CuNPs/BC proved high potential for PDS activation towards P4R decolorization.

Keywords

• biochar
• ponceau 4r
• one-pot synthesis
• copper nanoparticle
• biomass valorization
• rosemary extraction residue
• persulfate activation