Synthesis of a sulfated-group-riched carbonaceous catalyst and its application in the esterification of succinic acid and fructose dehydration to form HMF

A novel sulfated-group-riched sulfonated carbonaceous catalyst with high acidic strength and adjustable ratio of acidic groups was designed in the paper, where glucose and benzyl chloride were hydrothermally carbonized first followed by sulfonation treatment. Various physicochemical techniques were used to characterize the catalyst such as IR, 13C MAS NMR and XPS spectra, NH3-TPD, XRD patterns and TG curve. Then, it was applied in the esterification of succinic acid and fructose dehydration to form HMF. Compared to commercial Amberlyst-15 catalyst, such carbonaceous solid acid exhibited excellent catalytic activity and thermal stability, which was attributed to its higher amount of sulfonic acid group.

Application of Activated Carbon to Obtain Biodiesel from Vegetable Oils

The methanolysis of refined vegetable oils (rapeseed oil, sunflower oil, corn oil and olive oil) using a heterogeneous carbonaceous catalyst was studied. Activated carbon (AC) was prepared from beech tree wood and used as the support for KOH and a lipase catalyst. The reactions were carried out for 1–4 h at 60 °C with a methanol-to-oil molar ratio of 6:1 and 0.5–1.5 wt.% KOH/AC. In contrast, the biotransformation of vegetable oils was carried out for 24 h at 40 °C with an alcohol-to-oil molar ratio of 4:1 and 5 wt.% lipase/AC. The highest methanolysis yield (99%) for the fatty acid methyl esters was obtained for lipase/AC. These data show that activated carbon is a promising supporter for KOH as well as for lipase in the transesterification reaction of vegetable oils with methanol. The use of both catalysts in the transesterification reaction may improve biodiesel production. The lipase/AC enables the reduction in methanol excess and eliminates waste formation, whereas the saponification of triglycerides is scanty when KOH/AC is used.

Surface-Modified Sewage Sludge-Derived Carbonaceous Catalyst as a Persulfate Activator for Phenol Degradation

In this study, a catalytic persulfate oxidation process comprising sodium persulfate (PS) and modified sewage sludge-derived carbonaceous catalysts was tested for the degradation of phenol. Sludge-based biochar was modified by high-temperature treatment combined with hydrochloric acid oxidation. The surface properties of carbonaceous catalysts before and after modification were characterized by elemental analysis, N2 isothermal adsorption-desorption, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The effects of reaction parameters including catalyst dosage, PS/phenol molar ratio, initial pH and reaction temperature on the degradation rate of phenol were investigated. The kinetics of phenol transformation was explored and the reaction rate appeared pseudo first-order kinetics. In SS-600-HCl/PS system, 91% phenol could be efficiently degraded under certain reaction conditions ([phenol]0 = 100 mg/L, catalyst dosage = 0.8 g/L, PS/phenol molar ratio = 3/1, pH = 7, 25 °C) in 180 min. Thus, the results showed that the modified sewage sludge-derived carbonaceous catalyst had a better ability to activate PS for phenol degradation.