Recent advancements in the applications of activated carbon for the heavy metals and dyes removal

Abstract

Contaminated water resources, especially heavy metals, and dyes from industrial processes, pose a real threat to long-term and sustainable development goals. Activated carbon (AC) synthesis, their activation and modification to advanced and efficient material has been a target area of modern research work because of their distinguished properties; high surface areas (273–827 m2/g) and total pore volumes (0.27–0.69 ml/g), containing essentially micropores with diameters of 8.2 Å up to 12.4 Å, as well as surface chemistry. Most of the adsorption kinetics and isotherm for modified AC system fitted well with Langmuir and physical adsorption of pseudo-second order. The accumulate data on isotherm and kinetics indicate that modified AC has a huge potential for commercial applications, a part of its non-toxicity, low cost, and sustainability. Several parameters affecting the activation/modification and adsorption process including amount of adsorbent, pH medium, surface properties and concentration of water pollutants provide effect on adsorption efficiency of AC (75–96 %). Although, AC applications are rapidly growing, but still limited to batch levels. Considerations such as developing a simple and cost-effective approach for AC synthesis more specifically from non-degradable wastes have not been studied in detail. In addition, further studies on real wastewater systems are essential. This review highlights the wastewater treatment applications (heavy metals and dyes) of AC using adsorption technology and critically pinpoints the research gaps and suggestions for the future.