Catalytic Ozonation of Ibuprofen in Aqueous Media over Polyaniline–Derived Nitrogen Containing Carbon Nanostructures

Abstract

Catalytic ozonation is an important water treatment method among advanced oxidation processes (AOPs). Since the first development, catalytic ozonation has been consistently improved in terms of catalysts used and the optimization of operational parameters. The aim of this work is to compare the catalytic activity of polyaniline (PANI) and thermally treated polyaniline (PANI 900) in the catalytic ozonation of ibuprofen solutions at different pH values (4, 7, and 10). Catalysts were thoroughly characterized through multiple techniques (SEM, Raman spectroscopy, XPS, pHPZC, and so on), while the oxidation process of ibuprofen solutions (100 mgL−1) was assessed by several analytical methods (HPLC, UV254, TOC, COD, and BOD5). The experimental data demonstrate a significant improvement in ibuprofen removal in the presence of prepared solids (20 min for PANI 900 at pH10) compared with non-catalytic processes (56 min at pH 10). Moreover, the influence of solution pH was emphasized, showing that, in the basic region, the removal rate of organic substrate is higher than in acidic or neutral range. Ozone consumption mgO3/mg ibuprofen was considerably reduced for catalytic processes (17.55—PANI, 11.18—PANI 900) compared with the absence of catalysts (29.64). Hence, beside the ibuprofen degradation, the catalysts used are very active in the mineralization of organic substrate and/or formation of biodegradable compounds. The best removal rate of target pollutants and oxidation by-products was achieved by PANI 900, although raw polyaniline also presents important activity in the oxidation process. Therefore, it can be stated that polyaniline-based catalysts are effective in the oxidation processes.

Nanostructure Design of Catalysts: Latest Advances and Prospects

“…This Special Issue of Nanomaterials, entitled “Nanostructure Design of Catalysts: Latest Advances and Prospects”, combines relevant research and review contributions that cover the latest nanocatalysts. This Special Issue covers thermal catalysis [ 5 , 6 , 7 , 8 ], photocatalysis [ 9 ], electrocatalysis [ 10 ], and adsorbent nanomaterials [ 11 , 12 , 13 ]. It contains six research papers on nanometer materials for catalysts, including for thermal catalysis, photocatalysis, electrocatalysis, and other fields, which provide some new ideas for the nanostructure design of catalysts.…”

“…Advanced oxidation processes (AOPs) are considered to be one of the most promising methods to remove organic pollutants from the environment. For this purpose, Angel-Vasile et al [ 5 ] carbonized polyaniline (PANI) at 900 °C to prepare thermally treated polyaniline (PANI 900) and compared the presence of polyaniline at different pH values (4, 7, and 10) for the catalytic ozonation of an ibuprofen solution. The catalyst was characterized comprehensively by a variety of techniques (SEM, Raman spectroscopy, XPS, pHPZC, etc.…”