(434b) Novel Fruit Hydrochars: Eco-Friendly Solutions for Waste Management Challenges in Electronics and Agriculture Applications

African palm rachis, mango endocarps, mangosteen fruit rinds, moringa husk and blackberry bushes were cleaned, dried, and ground for further processing.Proximate composition analysis involved determining moisture, ash, total fat, proteins, and carbohydrates in the biomasses through specific methods like Soxhlet extraction and Kjeldahl method.Thermogravimetric analysis (TGA) was conducted on the raw materials to measure weight variations during heating, providing insights into composition and thermal stability. In the Hydrothermal Carbonization (HTC) process, biomass samples were processed in a high-pressure reactor with varying temperatures and times, followed by vacuum filtration to separate hydrochar from liquors. Chemical analyses, including Fourier Transform Infrared (FTIR) spectroscopy, were performed to identify functional groups and structural changes in the materials. X-Ray Diffraction analyses were performed to identify the relevant cristalline compounds present in the samples. To further complement these results, samples were pressed into pellets and subjected to frequency sweeps using a Semiconductor Device Parameter Analyzer to measure voltage retention capacity at different frequencies.

A statistical multicategorical method was selected for optimization through the p-value criterion, in which a threshold of 0.05 was used. The optimization method consisted on minimizing both conductivity and loss tangent where the "desirability" parameter is obtained from this process, where values close to 1 indicate a better optimization.

The desirability trends observed in the frequency range for both Mango Endocarps Hydrochars (MEH) and Mangosteen Rinds Hydrochars (MRH) exhibit similarities, which could indicative a correlation with their compositions. Soil electrical conductivity (EC) is crucial in agriculture, indicating soil's ability to conduct electricity, affected by factors like moisture, minerals, and temperature. Higher EC signifies more salt in soil, influencing nutrient availability and salinity. Examination of results show that both native mango and mangosteen materials share similar quantities of ash and proteins, and they are in the lowest range of the four materials analysed. This suggests a plausible association between the properties of the hydrochar and these identified variables, providing a basis for further exploration and analysis.