Potentiality of eggshell waste in synthesis of functional metal-organic frameworks for fuel purification

Abstract

Nitrogen containing compounds in the liquid fuel are well-known to cause serious corrosive action on the engines and plugging of filters with the formation of gummy compounds. Hence, the removal of nitrogenated compounds from the liquid fuel is highly demanded. The current study focused on the efficient removal of indole and quinoline (as nitrogenated compounds) by Ca based metal organic framework. Formerly, Ca based metal organic framework was synthesized using eggshell wastes as source of Ca by Solvothermal [Ca-BTC (s)] and Microwave [Ca-BTC (m)] techniques. Flower and shell plates like crystals were observed under microscope for the synthesized Ca-BTC (s) and Ca-BTC (m), respectively. Purification of liquid fuel from indole and quinoline by the obtained Ca-BTC was systematically investigated. The adsorption of nitrogenated compounds followed the second order reaction and Langmuir isotherm. Microwave technique showed to be more preferable rather than solvothermal technique, for preparation of Ca-BTC with significantly higher adsorption capacity, whereas, and the affinity was higher towards quinoline compared to indole. Meanwhile, for Ca-BTC (m), the estimated maximum adsorption capacity of indole and quinoline was 490.7 mg/g and 583.4 mg/g, respectively. After 4 regeneration cycles, the adsorption capacity Ca-BTC (m) was lowered by 29 % for indole and 24 % for quinoline. The obtained results confirmed the successful using of eggshell wastes in preparation of Ca-BTC with remarkable efficiency in the liquid fuel purification with quite good recyclability.