Ordered mesoporous carbons originated from non-edible polyethylene glycol 400 (PEG-400) for chloramphenicol antibiotic recovery from liquid phase

Abstract

Abstract Ordered mesoporous carbon (OMC) coded as ABA-16 has been successfully synthesized through hard-templating method using hexagonal mesoporous silica (HMS) as a template and non-edible polyethylene glycol 400 (PEG-400) as a liquid carbon source. The surface area of ABA-16 was measured at 1026 m 2 g −1 with the total pore volume of 0.99 cm 3 g −1 and the average pore diameter of 3.89 nm. The presence of ordered hexagonal structure in HMS and OMC was visualized through transmission electron microscopy (TEM). A series of batch adsorption studies was conducted on chloramphenicol (CPC) at different initial concentrations ranging from 50 to 400 mg L −1 at 303–323 K. The effect of pH on CPC adsorption was studied within the pH of 3–11. The maximum CPC monolayer adsorption capacity, Q m was 210 mg g −1 at 303 K. For all tested conditions, three-parameter adsorption isotherm models produced better fittings than the other two-parameter models. Pseudo-second order kinetic model gave a better fit to the experimental data compared to the other models. Thermodynamic studies suggested that CPC adsorption on ABA-16 was spontaneous and endothermic in nature. From the FTIR studies, it can be hypothesized that the two possible adsorption mechanisms; n – π interactions of carboxylic functional group on the carbon surface and the aromatics (benzene ring) of CPC, and π – π interactions of benzene rings in CPC with aromatics rings on the surface of the carbon. This work has clearly demonstrated that PEG-400 was a viable alternative for conventional edible/hazardous carbon sources used for nanocasting of OMCs.