Due to the negative consequences on human health, the economy, and the environment, water and wastewater are hot topics nowadays. Other considerations that contribute to the need of developing advanced separation and treatment technologies include the lack of potable water, the existence of many emerging and priority contaminants, and the requirement for removal of important trace substances.

To achieve sustainability goals, economic development must be achieved without placing undue strain on existing natural resources and with minimal environmental impact. As a result, a considerable shift in existing technology is necessary to increase production while lowering environmental effects and power costs. Separation methods such as the adsorption process are rapidly being used to address various elements of current environmental challenges, both economically and environmentally. Membrane separation technology is now recognized as one of the most essential critical solutions that can help the long-term development of water and gas separation methods by enhancing employment while using less energy and reducing pollution. The methods provide versatility and long-term viability. Adsorbent materials made of advanced functional materials like organic, inorganic, and polymeric composites might sometimes be easily regenerated for reusing, and efficiently retrieved and isolated with high added value. Structure relationships in the fabricated composite materials are extremely disputed subjects. Regarding physicochemical investigations and the molecular architecture of hybrid materials, more study is warranted.

This Special Issue seeks contributions of the composite materials in water and wastewater treatment through applying both adsorption and membrane technology. The underlying principles of adsorption and membrane processes, the fabrication and characterization of novel composites, and surface functionalization related selectivity to environmental implementations will be the emphasis of this Special Issue. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Water treatment membranes
• Polymeric nanocomposites in water treatment
• Eco-friendly biosorbents for water purification application
• Hybrid materials for heavy metals removal
• Carbon-based nanocomposites for water treatment
• Improvements in water and wastewater purification using adsorption technology
• New adsorbents for removal of disinfection byproducts from water
• Adsorption mechanisms
• Organic-inorganic, organic-organic, or inorganic-inorganic nanocomposite adsorbents for water and wastewater purification
• Physically blended hybrid polymeric materials for water and wastewater purification
• Polymer or biological composites/blends as adsorbents for water and wastewater purification
• Application of computational modeling of the hybrid polymeric nanocomposite materials in water and wastewater treatment