# A Thermogravimetric Analysis of Biomass Conversion to Biochar: Experimental and Kinetic Modeling
## 1 Introduction
The present research is based on an extensive search of academic literature, using the Web of Science (WOS) database, and the keyword: TS (Biomass) AND (TS=(biochar)) AND TS=(pyrolysis) AND TS=(kinetic analysis) AND (TS=(TGA)) OR TS=(Thermogravirtic Analysis). After finding the relevant papers (201 documents: 195 article types, 2 proceeding papers, and 3 review articles), we performed a cluster analysis with VOSviewer version 1.6.20, as seen in Figure 1 presenting the co-occurrence keyword diagram, which visually maps the relationships between key concepts associated with biomass, biochar, pyrolysis, and kinetic analysis. In the co-occurrence analysis, we included author keywords, while setting the minimum number of keyword occurrences to 5, resulting in a map with 21 thresholds. The centrality and connectivity of keywords, such as \"pyrolysis\", \"biochar\", \"biomass\", and \"kinetic analysis\", indicate their significant role in the research landscape related to thermogravimetric analysis (TGA) and thermal decomposition processes. The figure has different clusters represented by color-coded nodes:  
Red Cluster--Focuses on thermal analysis techniques like thermogravimetric analysis (TGA), kinetic parameters, and combustion; Green Cluster--Focuses on biomass conversion, thermodynamics, and biochar production, which is relevant to the investigation into  
Figure 1: Co-occurrence analysis of keywords. the influence of pyrolysis temperature on biochar properties; Yellow Cluster--Relates to the synergies in pyrolysis, adsorption properties, and surface characteristics of biochar; Blue Cluster--Represents characterization techniques and energy-related topics, potentially linking to the bioenergy applications of the pyrolysis process. What distinguishes this study from the broader research field evidenced in the diagram is its specific combination of methodologies and its focused investigation into the pyrolytic behavior of apple and potato peels--biomass types that are less frequently studied in this context. The use of multiple analytical techniques (FTIR, SEM, and EDS) to study the effect of pyrolysis temperature on the structural properties and surface chemistry of biochar adds significant depth to the research. This multidisciplinary approach is not always covered in similar studies. Hence, this study aims to investigate the impact of pyrolysis temperature on the kinetic parameters, physicochemical characteristics, and structural properties of apple and potato peels. The TGA was used to evaluate the pyrolytic decomposition of apple and potato peel waste. The kinetic analysis was performed based on single-step and multi-step models, and the results provided a thorough insight on the different mechanisms on the entire decomposition spectrum. The novelty of this research, according to our search in the Web of Science (WOS) database using terms \"(biochar) AND (apple peel) OR (potato peel) AND (nitrate removal)\", can be found in the investigation of both the pyrolysis behavior and the adsorption potential of biochar produced from biomass waste sources. By focusing on the detailed kinetic analysis, surface characterization, and adsorption potential of biochar from apple and potato peel, we believe this work fills an important gap in the current body of literature and adds new insights to sustainable biochar production and its environmental applications.