\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Absorbate** & **Absorbent** & **Initial Concentration** & **Absorbent Dosage** & **Time** & **Adsorption Capacity** & **References** \\ \hline \hline \multirow{6}{*}{Caffeine} & Peach stones & 100 mg & 0.12 g & 2 h & 126 mg/g & [9] \\ \cline{2-5}  & Acacia mangium wood & 100 mg & 3 g & 61 min & 30.9 mg/g & [10] \\ \cline{2-5}  & Date stone & 100 mg & 1 g & 80 min & 28 mg/g & [11] \\ \cline{2-5}  & Macrophytes & 150 mg & 1 g & 1 h & 117.8 mg/g & [12] \\ \cline{2-5}  & Acai seed & 300 mg & 1 g & 3 h & 176.8 mg/g & [13] \\ \cline{2-5}  & Pineapple Plant leaves & 500 mg & 1 g & 4 h & 152 mg/g & [14] \\ \cline{2-5}  & Sargassum & 20 mg & 0.6 g & 90 min & 221.6 mg/g & [15] \\ \cline{2-5}  & Pine Wood & 120 mg & 0.3 g & 5 h & 362 mg/g & [16] \\ \cline{2-5}  & Coffee waste & 25 mg & 0.1 g & 30 min & 274.2 mg/g & [17] \\ \cline{2-5}  & Elaeis guineensis & 20 mg & 0.2 g & 5 h & 13.5 mg/g & [18] \\ \cline{2-5}  & Eragrostis Plana Nees leaves & 200 mg & 0.07 g & 1 h & 235.5 mg/g & [19] \\ \cline{2-5}  & Aragan nutshells & 100 mg & 1 g & 90 min & 210.65 mg/g & This work \\ \hline \hline \multirow{6}{*}{Diclofenac} & Sycamore ball & 150 mg & 0.2 g & 2 h & 178.9 mg/g & [20] \\ \cline{2-5}  & Pine tree & 100 mg & 0.8 g & 2 h & 54.67 mg/g & [21] \\ \cline{2-5}  & Sugar cane bagasse & 50 mg & 0.4 g & 15 min & 315 mg/g & [22] \\ \cline{2-5}  & Cocoa shell & 150 mg & 1 g & 223 min & 63.47 mg/g & [23] \\ \cline{2-5}  & Tea waste & 30 mg & 0.3 g & 8 h & 62.5 mg/g & [24] \\ \cline{2-5}  & Potato peel waste & 50 mg & 0.4 g & 24 h & 68.5 mg/g & [25] \\ \cline{2-5}  & Olive-waste cakes & 50 mg & 0.1 g & 26 h & 56.2 mg/g & [26] \\ \cline{2-5}  & Pine sawdust-Onopordum & \multirow{2}{*}{100 mg} & \multirow{2}{*}{2.4 g} & \multirow{2}{*}{1 h} & \multirow{2}{*}{263.7 mg/g} & [27] \\  & acanthium & & & & & \\ \cline{2-5}  & Coconut shell & 200 mg & 0.5 g & 24 h & 103 mg/g & [28] \\ \cline{2-5}  & Peach stones & 100 mg & 0.12 g & 2 h & 200 mg/g & [9] \\ \cline{2-5}  & Orange peels & 0.5 mM & 0.5 g & 24 h & 52.2 mg/g & [29] \\ \hline \hline \multirow{2}{*}{Argan nutshells} & \multirow{2}{*}{100 mg} & \multirow{2}{*}{1 g} & \multirow{2}{*}{90 min} & \multirow{2}{*}{126.16 mg/g} & \multirow{2}{*}{Present work} \\ \cline{1-1} \cline{4-4}  & & & & & & \\ \cline{1-1} \cline{4-  
At present, the methods generally used to remove ECs from water basically include the microbial method [30], electrochemical method [31], adsorption method, membrane process, and chemical oxidation process [32]. Among them, adsorption is extensively accepted because of its advantages such as low cost, high efficiency, and wide processing range. Generally used adsorbents include activated carbon [33; 34; 35]. The mechanisms of adsorption are usually non-specific which could be employed to eliminate or reduce a large variety of contaminants [36]. Adsorption is a widely acknowledged surface phenomenon which is also a method for equilibrium separation as an effective process for removal of pollutants from the wastewater [37; 38; 39; 40]. Adsorption was observed to be advantageous over other wastewater treatment methods in terms of initial price, simple design, ease of use and non-sensitivity to harmful substances. Adsorption is therefore not allowing hazardous chemicals to form [41; 42; 43]. Presently, activated carbon is the most widely used adsorbent. It is substantially used to eliminate complex pollutants from wastewater, like dyes and heavy metals [44]. Activated carbon (AC) is a long-known adsorbent distinguished by, among other things, its large specific surface area, porous structure, and thermostability [45]. Activated carbon might be prepared from any solid material containing a high proportion of carbon often by carbonization followed by physical or chemical activation. However, a process combining both steps can be applied [46]. Carbonization is essentially aimed at enriching the material in carbon and creating the first pores, while activation aims at developing a porous structure [47].