Pyrolysis temperature effect on the efficacy of biochar/CuNi composite catalysts for emerging pollutant degradation

Abstract

Sugarcane pulp bagasse biochar (SCPBB) was produced through pyrolysis from 500 to 900 °C under a nitrogen atmosphere, and their SCPBB/CuNi composites was produced through wetness impregnation with copper and nickel salts followed by pyrolysis. The impact of pyrolysis temperature on SCPBB and SCPBB/CuNi for physic-chemical properties was evaluated. SEM images that spherical bimetallic CuNi nanoparticles were evenly dispersed on the surface of the biochar matrix, and the size of the nanoparticles increased with increasing temperature. In particular, when the pyrolysis temperature is higher than 700 °C, the nanoparticles on the surface exhibit novel structures that are partially embedded or completely enclosed within the porous biochar matrix. FT-IR ATR and Raman spectra proved that SCPBB materials contain abundant surface functional groups and carbonaceous structures, which were preserved by the introduction of metal nanoparticles. TGA demonstrated SCPBB-500 biochar started to lose mass quickly first, followed by SCPBB-700 and finally SCPBB-900, and the weight residues of SCPBB/CuNi increased by 30 %-34 % compared with SCPBB. In addition, the catalytic performance of the synthesized material was explored for the degradation of malachite green (MG) representing dye molecules, Amoxicillin (AMX) representing pharmaceuticals, and methyl-parabens (MP) representing personal care products contaminants. Each SCPBB/CuNi sample showed catalytic degradation performance under Advanted oxidation processes (AOPs), among which the SCPBB/CuNi catalyst obtained by pyrolysis temperature 500 °C performed best. Hence, SCPBB/CuNi demonstrates promising potential as a multifunctional catalyst for diverse environmental pollutants in wastewater treatments.