Exploring applications of ionic liquids in the coal industry by bibliometric analysis

Sustainable growth of the chemical industry is contingent upon efficient and clean coal exploitation, driven by rising global energy demand and stricter environmental regulations. Ionic liquids (ILs) exhibit substantial potential in the coal industry due to their ease of recovery, high solubility, and thermal stability. This study used bibliometric analysis to examine 551 journal articles on ILs in the coal industry from the Web of Science (WOS) database between 2000 and 2023. The articles cover coal desulfurisation (CD), extraction of coal (CE), coal liquefaction (CL), and spontaneous combustion of coal (CSC), accounting for 50% of the total literature (277 papers). The remaining studies (274 papers) focus on auxiliary fields, such as coal dissociation, gasification, and wettability. This categorization highlights the most prominent applications of ILs in addressing critical challenges in the coal industry. CiteSpace software visualizes the overall research trend, while VOSviewer analyses geographic distribution, publishing institutions, cooperation relations, and keywords. Current research focuses on ILs performance, separation, adsorption, and extraction. The keyword burst and time zone distribution map reveal that coal tar, models, imidazole, and nitrogen are emerging research directions. In this study, the application of ILs in the coal industry was comprehensively analyzed in-depth using the interdisciplinary research method of bibliometrics. It not only reveals the current research status and development trend but also provides important guidance and direction for future research.