Removal of carbamazepine from aqueous solution using carbon derived from date pits -

Abstract

The presence of pharmaceutically active compounds in water sources is of concern due to their persistence, potentially adverse effects on human health and on aquatic flora and fauna. The removal of pharmaceuticals from drinking water and treated wastewater effluent has become an important process treatment step. Activated carbon (AC) adsorption has proven to be an effective removal process for such compounds and a competitive alternative to other conventional treatment systems. A critical assessment of the existing literature is presented, highlighting research and development needs that will allow for more comprehensive application of AC adsorption for the removal of pharmaceuticals from the water environment. The removal of carbamazepine (CBZ) from aqueous solution by activated carbon produced by H₃PO₄ activation of date pits (DPAC) was investigated. Kinetics and equilibrium studies were performed using a batch experimental approach under various conditions where the effect of pH, temperature, contact time and adsorbent dose were studied. The microstructure of the activated carbon was determined using nitrogen adsorption-desorption, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). N₂ adsorption revealed the specific surface area (416 m²-g), pore volume (0.33 cm³-g) and pore size (3.1 nm). Equilibrium data were appropriately described by the Langmuir and Freundlich adsorption models, and the maximum adsorption capacity was reported at 7.22 mg-g of adsorbent. The thermodynamic study revealed the activation energy (25.73 kJ-mol), change in Gibbs free energy ∆G° (-9.96 kJ-mol), enthalpy ∆H° (31.55 kJ-mol) and entropy ∆S° (0.14 kJ-mol.K). Kinetic data suggested that adsorption of CBZ onto DPAC kinetics follows both the pseudo first and pseudo second order models. The adsorption mechanism was observed to be predominantly physical with the possible occurrence of some chemisorption processes. The regeneration of DPA