Agrochemical residues, including pesticides and herbicides, pose significant environmental and health risks when present in water sources. Conventional water treatment methods often fall short in effectively removing these persistent pollutants, necessitating innovative solutions. This review explores the use of polysaccharides and composite adsorbents as sustainable alternatives for agrochemical residue removal from water. Biopolymers such as chitosan, alginate, and cellulose are highlighted for their biodegradability, biocompatibility, and ability to be functionalized for enhanced adsorption performance. Recent advances in the development of composite materials incorporating nanomaterials, such as graphene, oxide, and metal oxides, have shown significant promise in enhancing the efficiency and selectivity of agrochemical adsorption. The review also addresses the fundamental mechanism of adsorption, such as electrostatic interactions, hydrogen bonding, and hydrophobic forces, that contribute to the effectiveness of these materials. Challenges associated with scalability, regeneration, and real-world applications are discussed, as well as future opportunities for integrating emerging technologies like 3D printing and machine learning into adsorbent design. Overall, polysaccharides and composites offer a promising pathway toward achieving efficient and sustainable agrochemical residue removal, with ongoing research needed to overcome current limitations and optimize their practical application in water treatment.

This article summarizes the findings of two of our own contributions and presents additional measurements that make us reach a conjecture about the physiological and molecular mechanisms that confer agaves their extraordinary capacity to withstand drought conditions. In these studies, we used terahertz (THz) spectroscopy and imaging to investigate the water retention mechanisms of agaves as well as the hydration dynamics of agave fructans, which are a peculiar type of carbohydrate produced by these plants. THz imaging was applied to map water distribution across different tissue regions, revealing a highly hydrated region in the core of the leaves and a less hydrated layer in the outside. Additionally, THz spectroscopy was used to study the hydration behavior of agave fructans in aqueous solutions. The hydration number and absorption coefficient increased nonlinearly with decreasing solute concentrations, reflecting the formation of complex hydration layers around these carbohydrates with an outstandingly large number of water molecules (∼320), which is 2 to 4 times larger than that of other carbohydrates such as inulin or maltodextrin. The findings underscore the importance of fructans in stabilizing membranes and enhancing drought tolerance by managing water at both tissue and molecular levels. This study demonstrates the versatility of THz technologies in plant science, offering a comprehensive approach to understanding water retention and hydration dynamics, with potential applications in improving agricultural practices for water-scarce environments.