The maximum adsorption capacity of activated carbon for a specific pollutant depends on the pollutant's properties, the activated carbon's characteristics, and the experimental conditions. It is typically determined using adsorption isotherms, such as the Langmuir or Freundlich isotherms, which describe the relationship between the amount of pollutant adsorbed and its equilibrium concentration in the solution.The adsorption capacity of activated carbon can be influenced by several factors, including pH, temperature, and initial pollutant concentration:1. pH: The pH of the solution can affect the adsorption capacity by altering the surface charge of the activated carbon and the ionization state of the pollutant. For example, at low pH values, the surface of the activated carbon may become positively charged, leading to a higher adsorption capacity for negatively charged pollutants. Conversely, at high pH values, the surface may become negatively charged, reducing the adsorption capacity for negatively charged pollutants. The optimal pH for maximum adsorption capacity depends on the specific pollutant and activated carbon used.2. Temperature: Temperature can influence the adsorption capacity through its effect on the adsorption kinetics and the equilibrium between the adsorbed and dissolved pollutant. Generally, increasing temperature can enhance the adsorption capacity if the adsorption process is endothermic absorbs heat , while decreasing temperature can improve the adsorption capacity if the process is exothermic releases heat . However, the specific effect of temperature on the adsorption capacity depends on the pollutant and the activated carbon used.3. Initial pollutant concentration: The initial concentration of the pollutant can affect the adsorption capacity by influencing the driving force for adsorption. At low initial concentrations, the adsorption capacity may be limited by the availability of pollutant molecules, while at high initial concentrations, the adsorption capacity may be limited by the availability of adsorption sites on the activated carbon. In general, the adsorption capacity increases with increasing initial pollutant concentration until a plateau is reached, indicating that all available adsorption sites are occupied.In summary, the maximum adsorption capacity of activated carbon for a specific pollutant depends on various factors, including the pollutant's properties, the activated carbon's characteristics, and the experimental conditions such as pH, temperature, and initial pollutant concentration. To determine the maximum adsorption capacity for a specific pollutant, it is essential to conduct experiments under different conditions and analyze the results using appropriate adsorption models.