Upgrading Fast Pyrolysis Oil through Decarboxylation by Using Red Mud as Neutralizing Agent for Ketones Production and Iron Recovery

Abstract

In this work, Red Mud, an alkaline solid waste from alumina production, was used as neutralizing agent to convert carboxylic acids in bio‐oil into ketones. The total acidity of the bio‐oil decreased significantly from 152.60 to 0.63 mg KOH/g, while the high heat value boosted from 17.25 to 29.57 MJ/kg. Meanwhile, the leachable alkalinity of Red Mud declined from 65.34 to 3.02 mg HCl/g, mitigating the harmfulness and perniciousness to the environment. Furthermore, characterizations of XRD, XPS and 57Fe Mössbauer spectroscopy indicated that the weak magnetic iron species in Red Mud was completely transformed into stronger magnetic Fe3O4. With magnetic separation the iron recovery reached up to 91.96 % with iron grade of 65.83 %, which is up to the standard of steelmaking raw material. The findings in this research not only open avenue for valorization of bio‐oil but also help explore the resourceful utilization of Red Mud.

Citric Acid Recovery and Methanol Production from a Waste Food Fruit Sample by Thermal Decomposition of a Reusable Zinc Citrate Complex

“…More importantly, the zinc citrate needs to decompose to form the different organic products and regenerate the ZnO to be recycled back into the recovery system. Previous studies have been conducted on the nature of magnesium and other carboxylate salts decomposition. − The salt of carboxylate anions eventually decomposed to produce the desired ketone at higher temperatures; however, the mechanism of the reactions is still unclear. This method has previously been used on a commercial scale to produce acetone from calcium acetate.…”