The increasing production of biowaste is becoming a major environmental issue. Every year, biowaste is generated in substantial amounts worldwide. Examples of biowastes include agricultural and forestry residues, animal waste, cattle manure, food industry, waste, industrial biowaste, and municipal solid biowaste. Waste is responsible for significant environmental and economic impacts in many countries. For sustainable global development, we must rethink how we can manage biowaste from a circular economy perspective.

Biowaste can be converted into value-added products, reducing the cost of disposal and environmental burden while generating additional revenues. Current trends consider biowaste as an operating supply. Great efforts are being made to transform biowastes into products so that they can be used for environmental remediation. For instance, these products can be used as soil amendments, adsorbents for the mitigation of toxic metal pollution of water, soil, or carbon dioxide capture. In particular, the adsorption process is a suitable technique for the removal of toxic metals because there are significant advantages such as cost-effectiveness, ease of operation, versatility, efficiency, and effectiveness.

The aim of this Special Issue is to bring together original research and review articles based on the concept of waste valorization and circular economy. We hope that this Special Issue provides a discussion platform for the present trends and advances in the area of biowaste recycling. Submissions should also discuss biowaste valorization into value-added materials for environmental remediation. We also hope that this Special Issue highlights current and new research discussing the adsorption process of biowaste-derived amendments cleaning up environmental contaminants.

Potential topics include but are not limited to the following:

• Adsorption processes for environmental remediation (e.g., competitive adsorption and air purification by adsorption)
• Kinetics and modelling of metal ion adsorption
• Adsorption filters for environmental remediation
• Removal of heavy metals with biowaste valorization
• Biowaste valorization for wastewater treatment
• Biowaste valorization for soil remediation
• Production and application of phosphate amendments
• Biowaste valorization (e.g., calcium-rich waste, eggshell waste, mollusc shell waste) for environmental remediation
• Recycling, reuse, and recovery of waste for environmental remediation
• Production and application of biochar for environmental remediation
• Valorization options for environmental remediation