Molten salt synthesis of hierarchically porous carbon for the efficient adsorptive removal of sodium diclofenac from aqueous effluents

Abstract

Pharmaceutical and personal care products (PPCPs) are emerging organic pollutants (EOPs) that pose a serious peril to both aquatic biota and mankind's health. The development of novel adsorbent materials for the effectual treatment of PPCPs-included wastewater has become one of the foremost research issues in the environmental research area. In this work, a hierarchical carbon material (GHPC), produced through the simple and effective molten salt route adopting glucose and the eutectic mixture (KCl/ZnCl2) as the carbon precursor and the pore generator, respectively, was applied in adsorption of sodium diclofenac, as a representative of organic contaminants of emerging concern, from aqueous solution. GHPC manifested superior adsorption performance towards DFC, which was believed to stem from its high surface area and total pore volume, hierarchically porous texture, and the presence of plentiful available functional groups. Langmuir adsorption isotherm, and the pseudo-second-order kinetics were found to be appropriate to represent the adsorption equilibrium and kinetics, respectively. Hydrogen bonding interaction was thought to be the main mechanism underlying DFC (as H-bond donor) adsorption onto GHPC (as H-bond acceptor). The impacts of the co-existing cations and anions on the adsorptive removal of DFC were additionally scrutinized. Finally, GHPC demonstrated good reusability properties that qualify it for the practical remediation of PPCPs-included wastewater.