A novel approach to remove ofloxacin antibiotic from industrial effluent using magnetic carbon nanocomposite prepared from sawdust of Dalbergia sissoo by batch and membrane hybrid technology

In this research work, the removal of ofloxacin (OFL) from industrial effluents were carried out through batch and membrane hybrid process using magnetic carbon nanocomposite (MCN) prepared from waste biomass (Dalbergia sissoo sawdust). The novel adsorbent was characterized by EDX (Energy dispersive x-ray), SEM (scanning electron microscopy), XRD (X-ray diffraction), FTIR (Fourier transform infrared), and TG/DTA (Thermal gravimetric/Differential thermal analysis). The deposited Fe3O4 (iron oxide) on the composite surface was confirmed through XRD, SEM, and FTIR. Batch adsorption experiments were performed in order to determine the optimal condition of adsorption and effect of various experimental parameters likes pH, contact time, adsorbent dosage, initial OFL concentration and temperature on the sorption process. Langmuir, Freundlich, Temkin, Jovanovic and Harkins-Jura models were used to determine different adsorption parameters. The kinetics data were analyzed using pseudo-first and second order, power function, Natarajan and Khalaf, and intraparticle diffusion models. The best fit was obtained with the pseudo-second order kinetic model. The value of Delta H degrees and Delta S degrees were found to be -27.948 and 110.17 kJ/mol indicating the exothermic and spontaneous nature of the process. An increase in adsorption with increase in temperature is evident from the values of Delta G degrees: -32.31, -33.41, -34.51 and -35.61 kJ/mol corresponding to 20, 30, 40, 50 and 60 degrees C. To evaluate the effect of MCN on membrane parameters, the continuous stirred reactor was connected with UF, NF, and RO membranes. Higher % retention and improved permeate flux were obtained for MCN/UF, MCN/NF, and MCN/RO processes. The percent retention of OFL observed for MCN/UF, MCN/NF, and MCN/RO hybrid processes were 57.8, 98.9 and 99.57 respectively.