Natural soil clays from a phaeozem to synthesize a nanocomposite with exhausted coffee grounds and ag-and tio₂-nanoparticles for water, air, or soil decontamination

A nanocomposite using natural clays from a Phaeozem soil, engineered Ag-nanoparticles (NP), TiO₂-NP, and exhausted coffee grounds was synthesized through a single-step by thermal method, to degrade or filtrate pollutants from soils, water or air. The surface characteristics and the porosity of the composite were studied through nitrogen gas adsorption and application of the Brunauer-Emmett-Teller (BET) equation, and the microporous composites ranged a surface area of 17.36 m² g^-1. X-ray diffraction showed the crystalline structure and crystalline phase of the nanocomposites. High-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy (STEM) demonstrated that TiO₂-NP surrounded Ag-NP, and both were impregnated on natural soil NP. Oxidation states of the Ag-NP and TiO₂-NP were analyzed by X-ray photoelectron spectroscopy (XPS). The energy gap of nanocomposite 8NC was determined by Ultraviolet-visible diffuse reflectance (UV–Visible DRS). The photocatalytic activity of this nanocomposite was evaluated. The results indicated that nanocomposite with Phaeozem-soil-NP (8NC) degraded 82.31% of the harmful organic compound methylene blue (MB) by 150 minutes, while the antimicrobial activity and resistance against Escherichia coli and Staphylococcus aureus and the zone of inhibition (ZOI) were 15 mm. The nanocomposite Ag-NP/TiO₂-NP/natural-soil-NP/exhausted coffee-ground showed its potential for the development of an efficient material for environmental remediation with photocatalytic and antimicrobial activity.