Various bio-materials are used in wastewater treatment to produce recycled water that can be used safely. Depending upon the methodology and the availability of indigenous resources, scientists have explored a variety of natural and synthetic materials for adsorptive and photocatalytic wastewater treatment, including agro-waste materials, and various clays, polymers, resins, or metal oxides. These can be utilized on an individual basis or in the form of composites to enhance their adsorptive or catalytic efficiency.

Polymer composites with biomaterials have been investigated extensively for use in wastewater treatment due to their durability, ease of preparation, and cost effectiveness. Researchers are now trying to make composites of various polymers and metal oxides from clay sources with agro-based waste materials to enhance cost effectiveness and recycling of agro-waste, in addition to the green synthesis of bio-nanocomposites that can be used for wastewater treatment on an industrial scale. In this way, their quality can be enhanced using minimal indigenous resources in an economical way. These composites may be developed either by combining various polymers or synthetic polymers with natural bio-waste or clay-type materials. In most cases, polymer composites materials have shown better performance compared to individual components for removing harmful contaminants from wastewater on a laboratory scale. Current challenges in this field include finding compatible materials and their specific ratios to get the desired properties correctly imparted to that specified composite, along with its on desk characterization.

The main aim of this Special Issue is to gather original research or review articles on biomaterials, specifically nanocomposites using agro-waste, metal salts, or polymers from local resources, and their physiochemical characterization, along with applications for adsorptive removal of contaminants from wastewater.

Potential topics include but are not limited to the following:

• Synthesis of novel bio-nanocomposites using indigenous resources and green technology, such as solvent-free methods or microwave assisted assembly
• Synthetic polymer composites with plant waste
• Metal salts composites with plant waste, such as peels, husks, leaves, seeds, bushes, and algae or fungi
• On-desk characterization of composites by physical, chemical, and spectroscopic methods
• Use of bio-nanocomposites for biosorptive elimination of dyes, toxic cations, and industrial waste from wastewater
• Comparison of adsorption behavior with reported methodologies
• Reviews focusing on recent trends in bio-composite synthesis or their applications
• Comparative studies using various types of bio-composites for dye and toxic metal ion removal by adsorption