Effects of Operating Conditions on Removal of Trace-amount Testosterone by Nitrocellulose Filter Membrane

Hormone can be removed by membrane filtration via membrane interception, sorption and diffusion. However, the effects of operating conditions of membrane filtration on hormone removal have not been evaluated systematically. In this study, the removal of testosterone by nitrocellulose membranes under different operating conditions (e.g., initial testosterone concentrations, sample volumes, flow rates and membrane pore sizes) was investigated. 14 C-labeled testosterone was used as a tracer to determine the removal of testosterone in the filtration process, and a hydrodynamic model was used to determine dispersion coefficient (D) associated with the operating conditions and radius of hormone molecule. Results indicate that the removal of testosterone decreases when the initial concentration, volume of testosterone solution, the flow rate or the pore size of the membrane increases. D was observed to vary with different operating conditions. Through curving fitting and parameter estimation, D can be expressed as a function of operating conditions, and the function can be used to predict hormone removal in the systems of the previous studies. This study has established, for the first time, the relationship among the hormone removal, operating conditions of membrane filtration and D, which was usually estimated with Stokes-Einstein equation in previous studies.