Magnetic optimizing surface-enhanced Raman scattering (SERS) strategy of detection and in-situ monitoring of photodegradation of Benzo[a]pyrene in water

Abstract

Background

Polycyclic aromatic hydrocarbons (PAHs) are one of the most dangerous persistent organic pollutants in the environment. Due to the discharge of chemical plants and domestic water, the existence of PAHs in sea water and lake water is harmful to human health. A method for rapid detection and removal of PAHs in water needs to be developed.

Results

In this work, we fabricate Fe₃O₄ wrapped with gold nanoparticles decorated graphene oxide composite nanomaterial (Fe₃O₄/GO/Au). Excellent magnetism of Fe₃O₄ provides a means to enrich and separate the PAHs from substrates, which effectively improve the selectivity and avoid the coffee ring effect in traditional SERS detection. Fe₃O₄/GO/Au shows great response to PAHs owing to the π-π electronic interaction between PAHs and GO, and through the calculation of Material Studio, it is confirmed that GO has different adsorption capacity for polycyclic aromatic hydrocarbons with different number of benzene rings. The limit of detection (LOD) of Benzo[a]pyrene (BaP) can reach 3.8 μg⋅L⁻¹ and other PAHs can also be detected at μg⋅L⁻¹ level. Gold nanoparticles demonstrate prominent light absorption within the visible spectrum and are characterized by their localized surface plasmon resonance (LSPR) properties. Meanwhile, Au NPs facilitate electron migration and carrier separation of GO. Owing to the synergistic interplay, the composite system Fe₃O₄/GO/Au exhibits the capability for SERS sensitive detection and photocatalytic degradation of BaP under visible light irradiation, realizing in-situ monitor the photodegradation of BaP in water.

Significance and novelty

A rapid and accurate quantitative method is established for the detection and removal of PAHs in water, which is intended to provide new strategy for the quantitative analysis and removal of water environmental pollution.