Development of low-cost activated carbon towards an eco-efficient removal of organic pollutants from oily wastewater

Abstract

The current study seeks to investigate the feasibility use of date palm kernels for the development of activated carbon (AC) towards its application, which functions as an adsorbent to treat oil-contaminated groundwater. Biochar derived from date palm kernels (BPK), was prepared by direct pyrolysis of the raw precursor at 600ºC for 90 minutes (in oxygen-limited condition). Activated carbon (ACPK) included similar pyrolysis conditions of biochar with subsequent impregnation in H2 SO4 (as activating agent) at a ratio of acid: biochar (1:1), moderate temperature. The analytical approach was performed through the use of XRD, BET, and FTIR, techniques to evaluate the effect of carbonization and activation process in improving the adsorptive properties of starting materials. Carbonaceous adsorbents obtained were highly porous due to their elevated specific surface area of (333.4 m²/g for BPK and 741.5 m²/g for ACPK) and their amorphous structure. Indeed, the textural proprieties were significantly improved by the acidic treatment. Further, the adsorption behavior of produced materials was tested by performing batch adsorption tests in contaminated water samples using a ratio of 1:1 (g/L) for 24 hours. The efficiency of adsorbents was evaluated by COD (C0 = 8568 mg/L), BOD5 (C0 = 200 mg/L) concentration, pH and hardness values before and after the treatment. Removal efficiency of COD for the BPK and ACPK samples reached 82.6% and 95.2% respectively, while for BOD5 was the same (97.0%) for both adsorbents. Additionally, the treated water sample has the same excellent class suitable for irrigation applications according to the Wilcox diagram. In consequence, the present study suggests an effective, eco-friendly and economical adsorption process intending to mitigate environmental risk sustainably.