Insights into Rice Husk Pyrolysis: Research Trends, Technological Advances, and Valorization Strategies

Rice (Oryza sativa L.) is a cereal crop cultivated worldwide for food, oils, and other applications. However, the processing of rice also generates large quantities of non-edible, solid residues called rice husks (RH), which account for 20% of the grain weight. The lack of effective and efficient strategies for handling RH has resulted in waste accumulation, thereby posing human health, safety, and environmental risks. To address these challenges, researchers have examined the treatment and valorisation potentials of RH through the pyrolysis process based on numerous research studies on rice husk pyrolysis (RHP) published and indexed in the Scopus database annually. Given the growing research interest and technological developments, there is an urgent need to examine the research climate and scientific landscape on RHP. Therefore, the paper presents the publication trends and a concise review of RHP based on the published documents in Scopus. The publication trends analysis revealed a geometric increase (3280% or 1,125 total published documents) from 2001 to 2021. The most prolific author on RHP research is Shuping Zhang (Nanjing University of Science and Technology), whereas the top affiliation is the Ministry of Education (China). The most cited funding organisation and country are the National Natural Science Foundation and the People Republic of China, respectively. A literature review revealed that RHP is an important research area due to the prominent publications, authors and citation counts on the topic. Lastly, the findings showed that pyrolysis is an effective technology for the treatment, disposal, valorisation, and management of RH wastes.