(506f) Comparative Study of Primary, Secondary, and Tertiary Amine-Functionalized PVDF Membranes for Dbsa Removal

Water remediation has become increasingly critical over the past decades due to the growing discharge of wastewater into the environment. Dodecylbenzene sulfonic acid (DBSA), a widely used surfactant and persistent pollutant, poses challenges for water treatment because of its high solubility and stability. In aqueous solutions, particularly at low pH, DBSA carries a negative charge due to its sulfonate group (–SO₃⁻), making electrostatic adsorption a viable removal strategy. To incorporate positive charges onto the membrane surface, amine functionalization through chemical grafting is employed. In this study, polyvinylidene difluoride (PVDF) membranes were first modified via graft polymerization of allyl glycidyl ether (AGE) for 5 hours, using methacrylic acid (MAAc) as a co-monomer to facilitate the process. Subsequently, three different diamines—1,3-diaminopropane (primary), 3-methylaminopropylamine (secondary), and N,N-dimethyl-1,3-propanediamine (tertiary)—were used to functionalize the membranes for 5 hours to enhance surface positivity. We hypothesized that modifying PVDF membranes with amines of varying functionalization would improve DBSA adsorption and allow for regeneration using sodium hydroxide (NaOH). Membrane characterization was performed using ATR-FTIR, SEM, contact angle goniometry, and BET analysis. A 500 ppm DBSA solution was used for all adsorption tests. Unmodified and AGE-modified PVDF membranes exhibited adsorption capacities of 27.4% and 35.3%, respectively. Membranes modified with primary, secondary, and tertiary diamines showed improved DBSA adsorption of 76.1%, 64.4%, and 80.2%, respectively. Ongoing tests will examine the effect of amine functionalization on regeneration using NaOH solutions.