A Critical Review of the Advances and Current Status of the Application of Adsorption in the Remediation of Micropollutants and Dyes Through the Use of Emerging Bio-Based Nanocomposites

The demand for drinking water is a reality that plagues modern society and will worsen in the coming decades. Factors such as climate change, population growth, and intense, often disorderly urbanization are expected to limit the availability of this essential resource for life. With this justification, several technologies involving water remediation/purification have been improved to increase energy efficiency. One key approach involves the use of residual biomass derived from biological sources as adsorbents with valuable properties. This line of research supports waste management, and the materials are easily obtainable, especially on a large scale, with low costs and negligible secondary environmental impacts. In the early 2000s, it was demonstrated that these materials possess functional groups (amino, hydroxyl, and carboxyl) that are favorable for attracting certain pollutants that are present in wastewater. Generally, the unmodified precursor material has properties that are not favorable for adsorption, such as limited adsorption capacity, low mechanical resistance, and unstable surface chemistry. Therefore, there has been a strong investment in studies aimed at developing methodologies to produce bio-based materials with high properties supported by mathematical models aimed at water purification. This critical review describes the modifications, functionalization, and production of bio-based materials aimed at remediating wastewater via the adsorption process. Their use involves the elimination of organic pollutants, water/oil separation, the removal of micropollutants, and membrane filtration. The properties of bio-based materials from biopolymers and their synthesis methodologies are analyzed, with a focus on water remediation. Finally, the challenges and future perspectives are highlighted, highlighting the relevance of this group of adsorbents in minimizing the challenges and limitations present in the field of water purification and providing new, innovative solutions.