Multifunctional and sustainable soot-modified nanofibrous membrane for adsorption, sensing and hydrogen peroxide electrogeneration.

The incineration of plastics and biomass is an efficient alternative to reduce the amount of solid waste and is also beneficial for energy production. Soot is one of the main byproducts generated during solid waste incineration, and so far, it has been treated as a pollutant. However, soot is an interesting nanostructured material displaying high specific surface area and chemical reactivity. In this work, soot produced by incomplete burning of plastic materials was combined with polymer nanofibers resulting in a multifunctional membrane explored for pollutant adsorption, sensing of organic pollutants, and in the electrogeneration of hydrogen peroxide. Specifically, soot was immobilized onto polyamide 6 nanofibrous membranes (NFM) produced by solution blow spinning following two different approaches: pre-synthesis and post-synthesis modification, and then the effect of soot chemical activation with NaOH was investigated. The adsorption tests showed that the chemical activation was essential to increase efficiency by improving its hydrophilicity and generation of adsorption sites. The experimental and calculated batch adsorption efficiency towards methylene blue was 94.33 mg/g and 37.71 mg/g, respectively. The adsorption efficiency in the fixed bed was 8.00 mg/g. The functional NFMs maintained their efficiency for at least ten adsorption cycles, increasing their economic viability. Furthermore, the NFMs were applied as flexible and free-standing electrodes for detecting methylene blue with a limit of detection of 2.4 nmol/L. The average per-electrode cost was estimated to be US$0.04. Finally, the NFM also demonstrated the ability to generate H 2 O 2 in situ. Altogether, these results suggest that the immobilization of soot onto nanofibrous membranes is an efficient strategy for developing multifunctional and sustainable materials towards environmental applications. [Display omitted] [ABSTRACT FROM AUTHOR]