Bettini Simona, Ottolini Michela, Pagano Rosanna, Pal Sudipto, Licciulli Antonio, Valli Ludovico, Giancane Gabriele
Department of Biological and Environmental Sciences and Technologies, DISTEBA, University of Salento, Via per Arnesano, I-73100 Lecce, Italy.
Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, INSTM, Via G. Giusti, 9, I-50121 Firenze, Italy.
Nanomaterials (Basel). 2021 Apr 21;11(5):1064. doi: 10.3390/nano11051064.
Carbon nanomaterials are a group of materials characterized by sp/sp carbon backbone which, combined with surface atoms and/or chemical groups, ensures peculiar physical chemical features for a wide range of applications. Among these materials, carbon dots and carbon nanoparticles belong to carbon nanomaterials with a few nanometer dimensions. In this work, carbon nanoparticles were produced from spent coffee grounds as sustainable carbon source through a simple, cheap and eco-friendly procedure according to an oxidation process (at controlled temperature) driven by hydrogen peroxide. Atomic Force Microscope (AFM) and fluorescence, UV-Vis absorption, FT-IR and Raman spectroscopy were used to assess the formation of carbon nanomaterials of about 10 nm with the typical emission and absorption properties of carbon dots and peculiar surface features. In fact, the presence of heteroatoms, i.e., phosphorus, and the carbonyl/carboxyl surface groups on carbon nanoparticles, was proposed to confer peculiar properties allowing the fast Mn(VII) reduction to Mn(II) at neutral pH and the Cr(VI) reduction to Cr(III) in weak acid aqueous media.
碳纳米材料是一类以sp/sp碳骨架为特征的材料，该骨架与表面原子和/或化学基团相结合，确保了其在广泛应用中具有独特的物理化学特性。在这些材料中，碳点和碳纳米颗粒属于几纳米尺寸的碳纳米材料。在这项工作中，通过过氧化氢驱动的氧化过程（在可控温度下），以废弃咖啡渣作为可持续碳源，通过简单、廉价且环保的程序制备了碳纳米颗粒。使用原子力显微镜（AFM）以及荧光、紫外可见吸收、傅里叶变换红外光谱（FT-IR）和拉曼光谱来评估约10纳米的碳纳米材料的形成情况，这些碳纳米材料具有碳点典型的发射和吸收特性以及独特的表面特征。事实上，有人提出碳纳米颗粒上存在杂原子（即磷）以及羰基/羧基表面基团赋予了其特殊性能，使得在中性pH条件下能快速将Mn(VII)还原为Mn(II)，在弱酸水介质中能将Cr(VI)还原为Cr(III)。
