Functionalized nanocellulose nanocomposite hydrogels for soil and water pollution prevention, remediation, and monitoring: A critical review on fabrication, application properties, and potential mechanisms

Soil and water pollution are current global environmental and agricultural challenges, adversely affected by ineffective industrial waste treatment before discharging into the environment combined with inefficient long-term inputs of fertilizers. The development of targeted fertilizers delivery vehicles, sufficient soil/water remediation, and contamination detection systems using eco-friendly technologies become critically important. Due to their high specific surface area, biocompatibility, easiness of operation, and high performance, nanomaterials-based controllable soil fertility promoters, adsorbents, sensors, and photocatalysts are promising tools for soil/water pollution prevention, remediation, and monitoring. Altogether, crystallinity, hydrophilic-tunable surface chemistry, and 3D forming ability of nanocellulose (NC), in addition to biodegradability, regeneration ability, and mechanical properties of NC nanocomposite hydrogels (NCHs), lead to advancing promising soil/water nanohydrogels-based targeted fertilizers delivery vehicles, adsorbents, co-adsorbents/co-sensors, and co-adsorbents/co-photocatalysts. In these systems, NCHs introduce 3D rigid porous scaffolds for homogenous dispersing/fixing of functional groups, fertilizers, fluorescence sources, and photocatalysts. Also, they present stimuli-responsive networks for fertilizer regulation in soil, and matrixes with extra active sites enabling contaminates immobilization/degradation. This review outlines an update of the most recent potential utilization of functionalized NCHs-based soil/water adsorbents, photocatalysts, sensors, and slow/targeted fertilizers release vehicles. An in-depth discussion of surface pretreatments-modifications used to improve their performance, fabrication methods, application properties, and working mechanisms was discussed. The potential limitations and future perspectives on using NCHs in fertilizer/water management, soil/water remediation, and detection are highlighted.