Ofloxacin and doxycycline competitive/binary adsorption on to MCM-41: isotherm modelling and evaluation

Abstract

ABSTRACT This work investigates the competitive adsorption of ofloxacin (OXC) and doxycycline (DCL) form OXC-DCL binary solution on to MCM-41, not reported earlier. Experiments were conducted at 288–318 K temperatures, and equilibrium adsorption isotherm data were analysed to study the competitive effect of the presence and absence of DCL on OXC adsorption and vice-versa in OXC-DCL binary solution. On this basis, the competitive interaction, Synergistic, Antagonistic and No interaction effects, for OXC and DCL adsorption was evaluated. Furthermore, the experimental equilibrium adsorption data were used for isotherm modelling using various multi-component competitive isotherm models such as extended Langmuir, extended Freundlich and Sheindorf–Rebuhn–Sheintuch (SRS) isotherms. It was found that single component adsorption for OXC, and OXC adsorption in the presence of DCL and vice-versa followed Freundlich and extended Freundlich isotherm model, respectively. The competitive adsorption interaction between OXC and DCL from their binary solution was found to be antagonistic at all temperatures.