Choi, Julius Lee (2017-12). Valorization of Ashe Juniper Waste into High Value-Added Products: Functionalized Biochar, and High Value Chemical. Doctoral Dissertation.
Thesis
Current biomass waste management such as landfills and combustion negatively affects the environment and public health. It is recognized that the production of biomass waste is unavoidable. Globally, 150 to 170 billion tons of biomass waste is annually available. For example, in central Texas, large amounts of Ashe Juniper waste is produced by the current management practices (hydraulic shear or bulldozer) to control population. However, biomass waste is expected as the only potential renewable carbon source alternative to petroleum-based products. Therefore, the development of the method to utilize biomass waste as carbon resource for the production of value-added products is highly required. In this dissertation, the methods for controlling biochar properties, and producing surface functionalized biochar and high value-added chemicals are developed. The method to control biochar properties is based on the concept of vacuum pyrolysis. By investigation of effects of vacuum pressure and temperature on the physicochemical properties of biochar, we confirmed that this method enabled us to produce biochar having potential applications as an adsorbent, a catalyst support, and a carbon sequestration agent. The method to produce functionalized biochar with high adsorption capacity for wastewater treatment was developed based on sulfuric acid treatment. The concentration of sulfuric acid was an important factor to control the adsorption capacity. The change of adsorption capacity was correlated to physicochemical properties such as surface area and surface functional groups. The developed functionalized biochar showed approximately 200 times improved adsorption capacity for dye chemicals compared to raw biochar. The influence of adsorption process parameter was conducted. Also, the biochar showed potential as a promising separator of certain dye chemicals in a multicomponent system. The method to obtain a high selectivity of Levoglucosenone (LGO), Furfural (FF), and levoglucosan is developed using catalytic pyrolysis and microwave-assisted pretreatment. LGO was only produced after treatment with CuSO4 and ZnSO4, which was attributed to dehydration of levoglucosan. Metal salt type and concentration affected the selectivity of LGO and FF by catalytic vacuum pyrolysis. Microwave solvothermal treatment affected pyrolysis characteristics and increased the selectivity of levoglucosan by approximately nine times.
