Efficient PPCP Removal by Activated Carbon

The adsorption process is often used for the successful removal of trace organic pollutants in water due to its simplicity, cost-effectiveness, efficiency at low concentrations, and minimal waste production [48 (link)]. Of the various adsorbents commonly available, AC is considered attractive for removing PPCPs from wastewater and is widely used not only in laboratory studies but also in pilot plant studies and full treatment plants [48 (link),49 (link),50 (link),51 (link)]. Liu et al. [52 (link)] reviewed the effectiveness of PPCP removal by AC. Table S2 summarises the removal efficiency of PPCPs by AC reported in several studies (Wang and Wang [6 (link)]). There are several mechanisms for removing PPCPs by AC, which are presented in Figure 2 [53 (link)]. Of these, the hydrophobicity and charge interactions of AC and PPCPs are the main ones [3 (link),11 (link),16 (link),36 (link),48 (link),53 (link),54 (link)]. Jamil et al. [48 (link)] classified 17 PPCPs found in a reverse osmosis concentrate collected from a water reclamation plant in Sydney into four groups based on hydrophobicity (log Kow values) and charge. They showed that PPCP removal by adsorption on granular AC (GAC) was related to charge and hydrophobicity (Figure 3). The PPCPs that had a positive charge and high hydrophobicity values (log Kow > 3.5) had the highest removal rates. Rodriguez et al. [55 ] agreed that the adsorption capacity of AC depends on the hydrophobicity of the investigated PPCPs (3-methylindole, chloroprene and nortriptyline). PPCPs can be adsorbed by both GAC and powder AC (PAC). Meinel et al. [54 (link)] discovered that the latter was more effective in the removal of PPCPs. AC removal of PPCPs can be improved by using ideal operating conditions, for instance, contact time, etc. According to Wang and Wang [6 (link)], this is best done with pilot-scale studies.