Emerging Strategies in Nanomaterial‐Engineered Biopolymeric Superabsorbents for Climate‐Resilient Water and Nutrient Management

ABSTRACT This review assesses the benefits of nanoparticle modified superabsorbents such as cellulose nanocrystal‐based SAPs, lignin‐based and cellulose‐based superabsorbent polymers that can absorb up to 825 g/g water due to advanced physicochemical interactions including hydrogen bonds and osmotic pressure‐driven swelling. This technology allows optimizing water retention in the soil, reducing the water consumption by 25%, nitrogen losses by 40%–70%, and phosphorus losses by 80%–90%. The improvement of soil water status is achieved due to the formation of a highly cross‐linked 3D network of polymers. However, the efficiency of such polymers depends on the effect of the environment on the superabsorbent polymers (SAP) properties, including their salinity and temperature, as their water absorption capacity can decrease under pressure. Natural and semi‐synthetic SAPs made from cellulose, starch, chitosan, and other natural polymers are promising materials that can be used as biodegradable alternatives to polyacrylic superabsorbent. However, a critical analysis reveals limitations in synthetic SAPs, such as environmental persistence and microplastic formation, necessitating a shift toward biodegradable alternatives. Nanotechnology integrations, like nanoclay modified SAPs retaining 80% capacity in saline soils (EC = 10 dS/m), promise enhanced performance, but challenges, such as elevated production costs and inconsistent performance across various soil types.