Natural organic matter (NOM), an underexplored resource for environmental conservation and remediation

Natural organic matter (NOM) is ubiquitous in the natural terrestrial and aquatic environment and has long been studied because of its unique constitutions and configurations. Despite the adverse environmental impacts, such as the formation of chlorine disinfection by-products (DBPs) and membrane fouling, its beneficial applications in the environmental aspects have recently attracted substantial research interest. The strong complexation and chelation effects of NOM towards metal ions and organic molecules due to the abundant content of functional groups provide great potential for applications in environmental conservation and remediation, including wastewater treatment, soil washing, soil erosion control, etc. Although many studies about the physiochemical properties and applications of NOM were reviewed, a comprehensive summarization and comparison of NOM applications in different environmental aspects are still not reported. Herein, this review focuses on the environmental applications of NOM as a valuable resource in soil remediation, water treatment, phytoremediation, soil erosion control and photocatalysis, including their working principles, recent developments and working efficiencies. The development and applications of synthetic humic-like acid (SHLA) in environmental remediation where the future challenge lies were also addressed. Finally, prospects on this topic are highlighted for existing technical challenges and outlooks.