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The present study reports the preparation of chemically activated carbons (PAC and ZAC) from apricot stones using phosphoric acid and zinc chloride, respectively. The potential use of the prepared carbons, as adsorbents, and the effect of chemical activation on the surface properties and adsorptive mechanism of nitrobenzene (NB) were investigated. The physicochemical properties of the obtained materials were characterized by Nitrogen adsorption-desorption isotherms, Scanning Electron Microscope, FTIR Spectroscopy, EDX analysis, Boehm titration, and pH of zero charge. The results show that the prepared samples present high apparent surface areas (1,382 and 1,111 m 2 /g for PAC and ZAC, respectively) and pores volumes with the presence of various functional groups. It was found that pseudo-second model was the most suitable for the fitting of the experimental kinetic data and the intraparticle diffusion was not the unique rate-controlling stage. The adsorption isotherms were well described by the Langmuir and the Freundlich models. According to the Langmuir model, the maximum adsorption capacity of PAC and ZAC were about 476.2 and 490.2 mg/g, respectively. The thermodynamic parameters showed the spontaneity, the exothermic nature, and the decrease in the randomness of the adsorption of nitrobenzene. Chemical regeneration showed that the prepared samples could be used for four time desorption-adsorption cycles with good efficiency for NB removal, indicating that the prepared carbons could be used as a low-cost alternative to commercial activated carbon for the removal of nitrobenzene from wastewater.

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The present work proposes an experimental strategy to prepare argan nutshell-derived porous carbons using potassium hydroxide (KOH). Several experimental parameters of the activation process were evaluated (temperature, impregnation ratio, and activation time), and an optimized carbon (ACK) was obtained. The surface properties of the ACK sample were determined, and the porous carbon was applied as an adsorbent of diclofenac (DCF) and paroxetine (PARX). A commercial carbon (CC) was used as a benchmark. The ACK porous carbon presented a higher surface area and micropore volume (1624 m2 g−1 and 0.40 cm3 g−1, respectively) than CC carbon (1030 m2 g−1 and 0.30 cm3 g−1, respectively), but the maximum adsorption capacities of DCF (214–217 mg g−1) and PARX (260–275 mg g−1) were comparable among the two carbons. Besides π-π interactions, H-bonds with the electronegative atoms of the adsorbate molecules and the electropositive H of the oxygen functional groups were appointed as the most probable mechanisms for adsorption onto ACK porous carbon. The electrostatic attraction was also considered, particularly for DCF with CC carbon. The pore size might have also been critical, since CC carbon presented more supermicropores (0.7–2 nm), which are usually more favorable toward the adsorption of pharmaceutical molecules. The reusability of the ACK carbon was tested up to four cycles of adsorption–desorption by using ultrasonic washing with water. The results indicated that no more than one cycle of use of ACK should be performed.