This review discusses the comprehensive assessment of various adsorbents for the removal of hazardous heavy metal ions from wastewater. The authors highlight the environmental and health risks associated with heavy metal contamination, emphasizing the need for efficient and sustainable treatment methods. The review covers the progress in the preparation and application of adsorbents based on carbon, micro-organisms, agricultural waste, and inorganic materials for the extraction of toxic metal ions such as Pb²⁺, Cr³⁺, As³⁺, As⁵⁺, Hg²⁺, and Cd²⁺. Key topics include the role of adsorbent homogeneity and heterogeneity, adsorption kinetics, reaction pathways, and solute uptake. The review also provides insights into the factors affecting the adsorption process, such as pH, contact time, porosity, adsorbent dose, temperature, initial pollutant concentration, and particle size. Additionally, it explores the use of carbon-based materials, biomaterials, and inorganic adsorbents, including their advantages and limitations. The review concludes with a discussion on the potential of agriculture waste-based adsorbents and the importance of optimizing functionalization processes to enhance adsorption efficiency.This review discusses the comprehensive assessment of various adsorbents for the removal of hazardous heavy metal ions from wastewater. The authors highlight the environmental and health risks associated with heavy metal contamination, emphasizing the need for efficient and sustainable treatment methods. The review covers the progress in the preparation and application of adsorbents based on carbon, micro-organisms, agricultural waste, and inorganic materials for the extraction of toxic metal ions such as Pb²⁺, Cr³⁺, As³⁺, As⁵⁺, Hg²⁺, and Cd²⁺. Key topics include the role of adsorbent homogeneity and heterogeneity, adsorption kinetics, reaction pathways, and solute uptake. The review also provides insights into the factors affecting the adsorption process, such as pH, contact time, porosity, adsorbent dose, temperature, initial pollutant concentration, and particle size. Additionally, it explores the use of carbon-based materials, biomaterials, and inorganic adsorbents, including their advantages and limitations. The review concludes with a discussion on the potential of agriculture waste-based adsorbents and the importance of optimizing functionalization processes to enhance adsorption efficiency.