Public health, production and preservation of food, development of environmentally friendly (cosmeto-)textiles and plastics, synthesis processes using green technology, and improvement of water quality, among other domains, can be controlled with the help of chitosan. It has been demonstrated that this biopolymer exhibits advantageous properties, such as biocompatibility, biodegradability, antimicrobial effect, mucoadhesive properties, film-forming capacity, elicitor of plant defenses, coagulant-flocculant ability, synergistic effect and adjuvant along with other substances and materials. In part, its versatility is attributed to the presence of ionizable and reactive primary amino groups that provide strong chemical interactions with small inorganic and organic substances, macromolecules, ions, and cell membranes/walls. Hence, chitosan has been used either to create new materials or to modify the properties of conventional materials applied on an industrial scale. Considering the relevance of strategic topics around the world, this review integrates recent studies and key background information constructed by different researchers designing chitosan-based materials with potential applications in the aforementioned concerns.

Currently, there is a growing concern regarding water remediation from agricultural and domestic wastewaters. Among water treatment methods, flocculation is a widely used approach. In this study, the bioflocculation of wastewaters from Sinaloa (Mexico) was examined using two bioflocculants: chitosan and bean straw flour (BSF). The jar-test results showed that chitosan exhibited high effectiveness in pollutant removal from different sampling zones (agricultural wastewater and river water). Additionally, this bioflocculant reduced remarkably the concentration of Mn and Fe. On the other hand, BSF showed high effectiveness in pollutant removal for a specific type of wastewater, being highly competitive as compared to chitosan. Besides, BSF led to 40% of Mn removal from highly contaminated river water samples. For both biomaterials, bioflocculation was driven by charge neutralization and sweep flocculation mechanisms. For a given agricultural wastewater sample, both bioflocculants performed better than the commercial poly(aluminum chloride) for pH regulation and Fe removal.