Application of biological and green nanomaterials in wastewater treatment: techniques for the effective removal of dyes, heavy metals, and organic pollutants.

Background/aim: Wastewater from industrial, agricultural, and residential sources poses significant environmental and public health risks due to the presence of dyes, heavy metals, and organic pollutants. Conventional treatment methods are often inadequate for the complete removal of these pollutants. Therefore, the development of sustainable, environmentally friendly, and highly efficient treatment techniques has become increasingly important. The aim of this review is to evaluate the application of biological and green nanomaterials in wastewater treatment and to compare their effectiveness against different types of pollutants (dyes, heavy metals, and organics). Materials and methods: This review provides detailed information on the removal of various pollutants from wastewater using green and biological nanomaterials, particularly based on articles published in recent years. The review examines the structures, synthesis methods, and application areas of biopolymers, metals, metal oxides, carbon-based, and polymer-structured nanomaterials synthesized using plant extracts and microorganism-supported systems. In addition, the integration of these nanomaterials with mechanisms such as adsorption, photocatalysis, bioseparation, and membrane filtration is discussed. Results: Green and biological nanomaterials demonstrate high performance in the removal of various pollutants owing to their low toxicity, large surface area, and diverse functional groups. The synthesis of these nanomaterials using biological agents both reduces environmental impact and enhances their purification capacity. However, further research and innovation are required regarding scale-up, long-term stability, reusability, and cost-effectiveness. Conclusion: Biological and green nanomaterials represent promising alternatives for sustainable wastewater treatment. This review summarizes the current status of these materials and provides guidance for future research. Multidisciplinary approaches and expanded pilot-scale studies are essential to accelerate the transition toward industrial applications.