Replacing carbon black with biochar, a more sustainable carbon negative material, in commercial inks will be presented. The overall project goal was to produce an optimal feedstock for biochar through impurity removal techniques. Biochar is most commonly used in soil applications or water remediation, due to its highly porous nature, leading to high contaminant adsorption. This project however, focuses on biochar as a pigment for lithographic inks. When raw boxboard or recycled paper pulp was subjected to pyrolysis, an appreciable amount of mineral impurities remained. These harder mineral impurities result in poor black coverage power. Harder mineral impurities also made mill processing more inefficient. A reasonable and sustainable purification process was required. New feedstock processing techniques were developed to remove, SiO2, TiO2, and CaO. Treatment effectiveness was confirmed using x-ray analysis to determine carbon and inorganic contaminant changes. The most effective treatments were a phosphoric acid treatment, and a floatation treatment which increased the carbon percentage 3% and 4%, respectively. The least effective contamination removal methods were flotation, acid digestion and hydrogen peroxide treatments, which decreased the carbon percent by 0%, 3%, and 6%, respectively. A significant increase in carbon content, up to 98% carbon by weight, was achieved when using the optimized pre-treatment processes. The biochar was then subjected to a range of pyrolysis temperatures ranging from 550oC and 1600oC in order to obtain a maximum black ink covering power. Lithographic printing inks were then formulated and print tested. With new contamination processing techniques, more biochar feedstocks can be introduced to the industry. Introducing more feedstocks, such as non-recyclable boxboard waste, has the potential to increase the sustainability of this technology. There is additional sustainable potential if current Technical Association of the Pulp and Paper Industry (TAPPI) covering power and color standards are loosened for the sake of producing sustainable inks.
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Hulse, Vanessa, "Biochar as a Substitute for Carbon Black in Lithographic Ink Production" (2019). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus