Special issue on biochar technologies, production, and environmental applications in <i>Critical Reviews in Environmental Science &amp; Technology</i> during 2017–2021

The engineered biochar has been extensively developed for environmental applications in the last decade, owing to its carbon-neutral and long-term persistent characteristics. Here, we addressed the advancement in production of novel engineered biochar with practical environmental remediation, and pointed out key challenges and future perspectives, based on total 28 publications in Critical Review in Environmental Science and Technology during 2017–2021. Without concerted efforts on engineered biochar-based environmental application integrating systematic research and environmental impact assessment, we are unlikely to achieve the circular economy-guided sustainable development.