Sustainable Recycling of Dairy-Based Effluents for Carbon Nanomaterial Synthesis: Technologies, Mechanisms, and Applications

This chapter examines how to use high-lactose and protein- and fat-containing dairy waste as a feedstock source of carbon to produce advanced carbon nanomaterials (CNMs). Four different processes used for valorizing dairy waste effluent into functional (carbon) materials are hydrothermal carbonization, pyrolysis, catalytic gasification, and bio-mediated processes. Therefore, special attention will be placed on reaction processes associated with carbonization, aromatization, and heteroatom doping, as well as pretreating to maximize yield of carbon and control the structure of carbon. The ability of both biomass-derived and metal organic framework (MOF)-based catalysts to catalyze graphitization, generate pore structure, and functionalize the surface of carbon nanomaterials will be critically assessed. In addition, the characterization of carbon nanomaterials produced will be assessed by a number of techniques including electron microscopy (e.g., ESEM), surface area measurement techniques (e.g., BET), and spectroscopy (e.g., FT-IR) for determining the structure and surface chemistry of the resulting carbon nanomaterials. From an (integrated) circular bioeconomy perspective, various technoeconomic indicators, energy recovery efficiencies, and environmental impacts will be assessed to determine the sustainability of the production of CNMs from the waste dairy materials. The functional applications of carbon nanomaterials made from dairy waste effluent including electrochemical energy storage and catalytic remediation of pollutants, as well as biomedical applications, will be assessed to illustrate the opportunity to convert large quantities of high organic waste into high-value carbon nanomaterials.