## 1 Introduction  
Activated carbons (ACs) are the most widely used adsorbent material. Their adsorbent properties are essentially attributed to their large surface area, microporous structure, high adsorption capacity, a high degree of surface functionality and reactivity, and a favourable pore size distribution, which improves the accessible internal surface and enhances the adsorption rate [1]. ACS can be used in a powdered or granular form (0.2-5 mm). Granular activated carbons (GAC) are widely applied as an adsorbent in liquids in several industries, representing around 82% of total AC use. However, AC is one of the most popular and widely applied adsorbents for removing organic and inorganic pollutants from water resources (drinking (31%) or ground (9%)) and wastewater treatment (22%) [2]. The global AC market size was estimated at USD 4.72 billion in 2018 and is expected to reach USD 14.66 billion by 2025. From 2019-2025, world AC consumption is projected to expand with 17.5% of GAC for water treatment and air purification [3]. The adsorption mechanisms of the AC results from interactions between the AC surface and the adsorbate. These interactions can be classified as electrostatic--if the adsorbate is an electrolyte and dissociates in an aqueous solution into ions (this interaction can be attractive or repulsive and depends on the AC charge density and pH\({}_{\text{PZC}}\), solution pH and ionic strength, and the adsorbate chemical characteristics) and ion exchange or non-electrostatic (always attractive) and can include: (a) van der Waals forces, (b) hydrophobic interactions, (c) \(\pi\)-\(\pi\) interactions and (d) hydrogen bonding) [4]. AC is known to be expensive including the environmental cost of the production/regeneration step. Therefore, identifying future promising alternative adsorbent materials is a key challenge for efficient yet affordable in the porous material industries. Nowadays, approaches have developed effective adsorbent materials such as graphene composites and transition metal carbides (MXene) with excellent performance and chemical and physical properties with the aim of adsorbing pollutants to improve the quality of effluents from productions processes [5; 6; 7; 8; 9; 10; 11]. Carbon-rich polymers are also another potential porous structure in material sciences with large specific surface areas and hierarchical porosities [12; 13]. Consumption of ACs for industrial use has now become an indicator of development and environmental management efficiency. Management of AC constitutes four main steps: (1) Characterization, (2) Application/exploitation, (3) Exhaustion, and (4) Regeneration. Characterization of AC is required in the first step because the application (second step) will depend on the textural and chemical properties of the porous material. During application/exploitation of the AC, this material will reach an exhausted condition (third step, saturation of textural and chemical properties) [14]. Once exhausted, AC should be regenerated (fourth step) because of environmental, industrial and economic benefits (recycling spent AC rather than disposal and replacing it with virgin material is generally less expensive), contributing to sustainability [14; 15; 16]. AC regeneration has several advantages, including reduced solid waste handling problems (reuse of material, avoiding polluting the environment because of dumping activity, avoiding the production of new AC, cost lowering effect) [17; 18; 19; 20; 21]. Virgin-produced AC releases over eight times more carbon dioxide equivalents compared to regenerated AC. The potential for regeneration in any process turns into a comprehensive decrease of the environmental footprint [20]. The implementation of AC management in any industry should enable a strategy to permit the control, monitoring and performance optimization in the use of the adsorbent [14]. However, this practice is not implemented in all industries and especially not in developing countries.