Abstract
Utilization of biomass either as a renewable energy source or for the generation of biogenic materials has received considerable interest during the past years. In the case of rice husk (RH) and rice straw (RS) with high silica contents in the fuel ash, these approaches can be combined to produce high-grade biogenic silica with purities >98 wt % from combustion residues. The overall process can be considered nearly neutral in terms of CO2 emission and global warming, but it can also address disposal challenges of rice husk and rice straw. For the resulting biogenic silica, several advanced application opportunities exist, e.g., as adsorbents, catalysts, drug delivery systems, etc. This article provides a comprehensive literature review on rice husk and rice straw combustion as well as applied strategies for raw material pre-treatment and/or post-treatment of resulting ashes to obtain high quality biogenic silica. Purity of up to 97.2 wt % SiO2 can be reached by combustion of untreated material. With appropriate fuel pre-treatment and ash post-treatment, biogenic silica with purity up to 99.7 wt % can be achieved. Studies were performed almost exclusively at a laboratory scale.
Highlights
According to the report of International Energy Agency (IEA) in 2017, the worldwide share of renewable energy reached 23.9% in the electricity sector, 10.3% for power production and 3.4%for transportation
Remaining carbon in the ash is high for rice husk ash (RHA) obtained at 700 ◦ C compared to the RHA produced at 600 ◦ C
WRH had no change in ash content when the residence time (RT) is longer than 1.5 h, which implies no carbon residues in RHA, and it was interpreted as an indication for pure silica production from WRH
Summary
According to the report of International Energy Agency (IEA) in 2017, the worldwide share of renewable energy reached 23.9% in the electricity sector, 10.3% for power production and 3.4%for transportation. Biomass needs to fulfill the following criteria as a sustainable resource of energy: (1) it should be readily available; (2) arable land for food resources should not be affected by biomass for energy generation; and (3) it should produce zero waste and have no negative impact on the environment [2]. In this regard, rice husk (RH) and rice straw (RS) as by-products in rice production and milling processes can fulfill these criteria.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
