| The presence of phenolic compounds in petroleum refining wastewater is a matter of concern for both environmental agencies and refiners. This is mainly due to their toxicity to aquatic organisms and the naturally high oxygen demand that phenolic compounds do impose on aquatics streams. This work reports the results of phenol adsorption from aqueous solutions on graphene prepared from graphite nanoplatelet named as G1. For comparison purposes, different commercial types of activated carbon were also tested under similar conditions. The used carbons were NORIT W-35, NORIT RB2H2 and Nuchar granular.;The effects of different operating parameters on phenol adsorption were investigated including phenol initial concentration, adsorbent dosage, contact time, shaking speed and temperature. The maximum uptake of commercial activated carbons was less than that of graphene. For instance, the maximum uptake of graphene was 233 mg/g whereas the maximum uptake of W-35, Nuchar granular and RB2H2 was 200, 167 and 91 mg/g, respectively. Freundlich and Langmuir isotherm models were fitted to the experimental data. The kinetic studies illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model.;Given the high cost of graphene (600 dirhams for 25 mg) compared to activated carbon (around 700 dirhams for 1 kg) and the small difference between the adsorption capacity of graphene and W-35. W-35 looks more promising as a phenol adsorbent. |
