Nanocrystalline Cellulose-Derived Doped Carbonaceous Material for Rapid Mineralization of Nitrophenols under Visible Light

[Image: see text] Nitrophenols (NPs) and related derivatives are industrially important chemicals, used notably to synthesize pharmaceuticals, insecticides, herbicides, and pesticides. However, NPs and their metabolites are highly toxic and mutagenic. They pose a serious threat to human health and ecosystem. Current work was undertaken to develop a suitable visible-light active catalyst for the sustainable and efficient mineralization of NPs in an aqueous environment. Nanocrystalline cellulose (NCs)-based nitrogen-doped titanium dioxide and carbonaceous material (N-TiO(2)/C) was synthesized by pyrolysis and sol–gel methods using NCs, polydopamine, and TiO(2). The synthesized N-TiO(2)/C was characterized using different analytical techniques. Photocatalytic degradation of NPs under visible light indicated that acidic pH (3) was most suitable for the optimal degradation. 4-NP degradation followed both pseudo-first-order (R(2) = 0.9985) and Langmuir–Hinshelwood adsorption kinetic models (adsorption constant, K(LH) = 1.13 L mg(–1)). Gas chromatography–mass spectrometry and ion chromatography analysis confirmed the total mineralization of 4-NP into smaller molecular fragments such as acids, alcohols, and nitrates. The total organic carbon showed that 67% of total carbon present in 4-NP was mineralized into CO(2) and CO. The catalyst was recycled for five consecutive cycles without losing its catalytic activities. The degradation mechanism of NPs with N-TiO(2)/C was also explored.