Rice husk ash as green and sustainable biomass waste for construction and renewable energy applications: a review

Due to the numerous downsides associated with the non-renewable energy sources, the global attention is increasingly diverting towards using renewable sources. Among many others, the biomass of agricultural crops is shown to be a promising non-renewable energy source, hence becoming a preferable choice to extract/synthesize value added products. In this respect, rice husk has shown its potential time and again. As an example, rice husk can be converted into ash which is already an investigated source of rich silica content, and therefore can be utilized in the relevant applications. Agricultural biomass and its waste have gravitated a significant interest of researchers around the globe due to their low reaction time and high utilization. The present review explores the novel and recent green/sustainable applications of rice husk/rice husk ash in various engineering, industrial, and other renewable energy applications. Moreover, it gives a background of agro-waste applications along with a comparative study of achievable silica from rice husk and other agro-waste sources.