A review on activated carbon modifications for the treatment of wastewater containing anionic dyes

Polluted water resources, particularly those polluted with industrial effluents' dyes, are carcinogenic and hence pose a severe threat to sustainable and longstanding worldwide development. Meanwhile, adsorption is a promising process for polluted/wastewater treatment. In particular, activated carbon (AC) is popular among various wastewater treatment adsorbents, especially in the organic contaminants' remediation in wastewater. Hence, the AC's synthesis from degradable and non-degradable resources, the carbon activation involved in the AC synthesis, and the AC's modification to cutting-edge and effective materials have been modern-research targets in recent years. Likewise, the main research focuses worldwide have been the salient AC characteris-tics, such as its surface chemistry, porosity, and enhanced surface area. Notably, various modified-AC synthesis methods have been employed to enhance the AC's potential for improved contaminants-removal. Hence, we critically analyze the different modified ACs (with enhanced (surface) functional groups and textural properties) of their capacity to remove different-natured anionic dyes in wastewater. We also discuss the corresponding AC modification techniques, the factors affecting the AC properties, and the modifying agents' influence on the AC's morphological/adsorptive properties. Finally, the AC research of future interest has been proposed by identifying the current AC research gaps, especially related to the AC's application in wastewater treatment.

Automated summary

Polluted water resources, especially those contaminated with industrial effluents' dyes, pose a severe threat to sustainable development. Adsorption, particularly using activated carbon (AC), is a promising method for wastewater treatment. The synthesis, activation, and modification of AC have been the focus of recent research. Various modified-AC synthesis methods have been investigated to enhance its capacity for removing different-natured dyes in wastewater. The surface chemistry, porosity, and enhanced surface area of AC are important characteristics. Understanding the AC modification techniques, factors affecting its properties, and the influence of modifying agents on its morphology and adsorptive properties is crucial for wastewater treatment.