Advances in biomass thermochemical conversion on phosphorus recovery: water eutrophication prevention and remediation

The scarcity of phosphate ores and increasing water eutrophication are driving economically attractive and environment-friendly approaches for phosphorus recovery. The biomass thermochemical conversion process enables effective protection against water eutrophication caused by phosphorus loss, while allowing the remediation of water eutrophication. This review focuses on the main reaction processes for phosphorus recovery from phosphorus-rich biomass (e.g., sewage sludge and food waste) as secondary phosphorus sources through biomass thermochemical conversion (pyrolysis - pyrochar, hydrothermal - hydrochar, and hydrothermal humification - artificial humic substances). Also, revealing the contribution mechanisms (ligand exchange, electrostatic attraction, and surface precipitation) of phosphate adsorption on metal-modified high-carbon containing lignocellulosic biomass (e.g., crop straw and fruit shells) thermochemical transformation products. This review provides insight on the possibility, superiority, and extensiveness for the prevention and remediation of water eutrophication through biomass thermochemical conversion, and contributes to the further development and application of phosphorus recovery.