Eco-friendly and effectively glyphosate removal using novel banana peel-derived biopolymer-supported CoFe2O4 activated peroxydisulfate: kinetic and mechanism insights.

Abstract

In this work, an eco-friendly and novel heterogeneous catalyst deriving biopolymer extracted from banana peel for supporting CoFe₂O₄ (CoFe₂O₄@BP-BiP) was successfully developed to activate peroxydisulfate (PDS) for mineralization removal of glyphosate (GP) herbicide from wastewater. GP mineralization performance, evaluating via COD removal efficiency, in CoFe₂O₄@BP-BiP/PDS system was compared with that in CoFe₂O₄/PDS system under various operational conditions. The chemical-physical properties were systematically analyzed to explore the mineralization mechanisms of GP. Quenching and competitive anion tests were conducted to study mineralization mechanisms of GP by CoFe₂O₄@BP-BiP activing PDS during catalytic process. The results illustrate that composition of BP-BiP and CoFe₂O₄ remarkably reduced the agglomeration of nanoparticles and enriching oxygen-containing functional groups (OCFGs), which accelerated electron transfer cycles of Co³⁺/Co²⁺ and Fe³⁺/Fe²⁺ redox couples to continuously regenerate Fe²⁺ and Co²⁺. This led to the effective decomposition of PDS, generating more reactive oxygen species (ROS) for promoted mineralization of GP. CoFe₂O₄@BP-BiP system exhibited higher GP mineralization performance and rate, approximately twofold greater than the CoFe₂O₄/PDS system. Mechanistic studies showed that GP mineralization occurred via both non-free radical and free radical pathways, involving ROS such as singlet oxygen (¹O₂) and radicals (^*SO₄^-, ^*OH, ^*O₂^-). Additionally, CoFe₂O₄@BP-BiP demonstrated excellent stability and reusability across five consecutive runs with minimal Co and Fe leaching. These findings suggest that CoFe₂O₄@BP-BiP is an effective and sustainable catalyst for activating PDS in the removal of glyphosate from wastewater.