Development of glycerol-based metal-free carbon materials for environmental catalytic applications

Abstract

A thermally stable and non-porous carbon material (S BET = 10 m 2 g −1 and no micropores), with low ash content and basic character, was produced by partial carbonization of glycerol with sulphuric acid followed by calcination under inert atmosphere. Further thermal activation in air atmosphere at different temperatures (from 150 to 350 • C) leads to materials with less basic character and to a tremendous evolution of the porosity, mostly microporosity (S BET = 598 m 2 g −1 and V Mic = 0.24 cm 3 g −1 ). Experiments show that metal-free carbon materials synthesized by this approach can be highly active catalysts for the catalytic wet peroxide oxidation (CWPO) process when the surface chemistry and textural properties are adequately tuned. Effective catalytic degradation of 2-nitrophenol (80% conversion) was achieved with the material treated under air atmosphere at 300 • C, even when operating under a high pollutant/catalyst mass ratio, opening a window of opportunity for added-value crude glycerol-derived products. Furthermore, catalyst activity was effectively recovered by a simple oxidative thermal regeneration procedure.

Hybrid magnetic graphitic nanocomposites for catalytic wet peroxide oxidation applications

“…As observed, 4-NP removal slightly decreases from 100%, in the first run, to 96%, in the fourth run, in the experiments performed with 200 mg L −1 4-NP solutions. As previously shown in the CWPO of phenol over microporous activated carbon catalysts [26], as well as in the CWPO of 2-nitrophenol over glycerol-based carbon catalysts [27], the decrease of the MGNC catalytic activity may be partially caused by 4-NP reaction by-products adsorbed or deposited on the carbon surface, which limit the accessibility to the active sites. Nevertheless, the pollutant mass removal obtained in the fourth CWPO cycle performed with MGNC (4808 mg g −1 h −1 ) is still far above the values reported in CWPO processes performed with carbon-based [13] and magnetite-based catalysts [25].…”

Magnetic carbon xerogels for the catalytic wet peroxide oxidation of sulfamethoxazole in environmentally relevant water matrices

“…However, this solution frequently leads to catalysts with limited stability, mainly due to the leaching phenomenon [20,29,30]. At the same time, carbon materials with easily tuned properties, such as activated carbons [31], graphite [32], carbon nanotubes [33], carbon blacks [34], carbon aerogels [35], activated carbon xerogels [36], glycerolbased carbon materials [37] and graphene-based materials [38], have been reported as active and efficient catalysts for CWPO, although with lower performances when compared to metal-based catalysts [39]. More recently, the improved catalytic performance of highly stable carbon-based composites containing active metallic materials within their carbonaceous structure has been shown and reported as the next step in the evolution of catalysts for CWPO [39].…”

Role of Nitrogen Doping on the Performance of Carbon Nanotube Catalysts: A Catalytic Wet Peroxide Oxidation Application

“…Recently, metal‐free carbon‐based materials were found to be promising catalysts for CWPO, showing high activity and stability and the ability to ensure an efficient H 2 O 2 usage, that is, the selective formation of HO . and further effective reaction with pollutant molecules …”