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Volcanic ash is frequently referenced as natural particles, yet few applications for wastewater purification and surface-enhanced Raman scattering (SERS) have been reported. Here, a unique micro/nanostructured nozzle-shaped volcanic ash was characterized. The natural volcanic ash had an ordered porous structure with an average diameter of 20 µm. Macropores with 200-nm pore size and 3–5-nm mesopores were homogeneously distributed on the surface of the volcanic ash. The volcanic ash provided an efficient water purification for simulated dye and livestock wastewater. The volcanic ash/silver nanoparticle hybrid also exhibited strong SERS. Moreover, the differing adsorption sequence of silver nanoparticles and probes on the surface of volcanic ash created distinctive enhancements. The micro/nanostructured volcanic ash was shown to be a promising water purifying agent and platform for SERS in environmental monitoring. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor was fabricated by modifying the glass carbon electrode surface with CuS nanocomposites and chitosan for the determination of pentachlorophenol. CuS nanocomposites obtained by a solvothermal method were composed primarily of CuS with hexagonal phase and Cu2Cl(OH)3with a tetragonal phase. The results indicated that CuS nanocomposites possessed good electrochemical activity. After optimizing the experimental conditions, the linear dependence of current vs. pentachlorophenol concentration was reached in a range from 1.88 × 10−6–7.50 × 10−5 mol/L pentachlorophenol, and the detection limit was 6.25 × 10−7 mol/L. The electrode displayed a high degree of stability and reproducibility. A new, simple, rapid, and highly sensitive electrochemical detection method of pentachlorophenol was established. [ABSTRACT FROM AUTHOR]