GREEN SYNTHESIS OF DIATOM-BASED ADSORBENTS DOPED WITH GOLD NANOPARTICLES FOR EFFICIENT HEAVY METAL REMOVAL

Abstract

This research introduces an environmentally conscious methodology aimed at mitigating heavy metal contamination in aquatic environments, addressing the pressing demand for sustainable water purification methodologies. A novel approach to synthesis is proposed for creating a specialized adsorbent composite derived from diatoms and enhanced with gold nanoparticles (Dtm-AuNPs). The eco-friendly synthesis process employs ultrasound-assisted heterogeneous nucleation, utilizing Piper auritum extract as a biogenic reducing agent for the production of AuNPs. The resulting Dtm-AuNPs composite offers a non-toxic, uncomplicated, and efficient solution for the removal of Mn2+ ions from aqueous solutions. Characterization techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and infrared spectroscopy validate the formation of Dtm-AuNPs and provide insights into the diatom´s composition. The adsorption capacity of Dtm-AuNPs for Mn2+ ions was assessed experimentally, achieving notable efficiencies of up to 98% within a maximum adsorption duration of 240 minutes, particularly when assisted by sonication. Both linear and nonlinear kinetic models were utilized, with the pseudosecond-order nonlinear (PSO-NL) model demonstrating optimal fitting for the adsorption process. This environmentally friendly approach presents a promising avenue for the development of highly efficient adsorbents with minimal ecological and economic impact, thus contributing to the progression of sustainable water treatment methodologies.