{'fraction_non_alphanumeric': 0.05386178861788618, 'fraction_numerical': 0.029471544715447155, 'mean_word_length': 5.080246913580247, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Electrochemical Sensor Based on Electrospun Three-Dimensional Carbon Nanofibers to Determine Trace Levels of Cu(II)

In this study, a three-dimensional carbon nanofiber network was formed by first electrospinning a mixed solution of montmorillonite (MMT) and polyacrylonitrile (PAN), and then carbonizing the composite nanofiber and etching it with hydrofluoric acid. The form and morphology of the nanofibers
 were analysized by scanning electron microscopy (SEM), Raman microspectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS). The sensor fabricated on three-dimensional carbon nanofiber showed a good linear response (y = 0.076x – 0.110, R2 = 0.999,
 and y = 0.193x – 1.770, R2 = 0.998), high stability and selectivity, and a low detection limit (0.4 μg · L–1) for Cu(II) as measured using differential pulse voltammetry under the optimal conditions, and the method mentioned
 above was also used to analyze Cu(II) in real tap water samples, which had good recoveries.