Evaluation of Adsorption Capacity of Chitosan-Citral Schiff Base for Wastewater Pre-Treatment in Dairy Industries

In this study, we aimed to evaluate the adsorption capacity of the Schiff base chitosan-citral for its application in dairy wastewater pre-treatment. Chemical oxygen demand (COD) reduction was the factor used to evaluate the adsorption efficiency. The maximum COD percentage reduction of 35.3% was obtained at 40.0 °C, pH 9.0, adsorbent dose 15 g L-1, contact time 180 min and agitation speed 100 rpm. It was found that the Langmuir isotherm fitted well the equilibrium data of COD uptake (R2 = 0.968), whereas the kinetic data were best fitted by the pseudo-second order model (R2=0.999). Enhancement of the adsorption efficiency up to 29.8% in dependence of the initial COD concentration of the dairy wastewater was observed by adsorption with the Schiff base chitosan-citral adsorbent compared to the non-modified chitosan at the same experimental conditions. The results indicated that the Schiff base chitosan-citral can be used for dairy wastewater physicochemical pre- treatment by adsorption, which might be applied before the biological unit in the wastewater treatment plant to reduce the load.