Efficient chemo-catalytic transformation of spent coffee grounds into lactic acid using erbium triflate

Abstract

Developing efficient conversion technologies for waste valorization is crucial in the context of a sustainable bioeconomy. The massive generation of spent coffee grounds (SCG) has become an environmental and social concern. Although the majority of SCG is underutilized, it exhibits the potential to be converted into value-added products. Herein, we report the effective production of lactic acid (LA), a precursor of polylactic acid, from SCG through catalytic upcycling using an erbium triflate catalyst. The reaction conditions, including time, temperature, and catalyst loading, were optimized to maximize the LA yield. The proposed strategy converted SCG into LA with a high yield (70 mol%) within 1 h. The morphology and chemical structure of SCG were investigated. Additionally, a techno-economic analysis (TEA) was conducted, which demonstrated that an economically viable catalytic upcycling strategy can enhance the efficiency of the waste valorization process.