Innate connection between salts on preparation and separation performance of Thin-film Poly (piperazinamide) composite membrane

Abstract

ABSTRACT The development of thin-film polyamide composite membranes is a revolutionary aspect of the history of membrane science. ‘Wet phase inversion’ and ‘interfacial polymerization’ are two important steps in preparing thin-film polyamide composite (TFC) membranes. Poly (piperazinamide) TFC membranes make a strong pitch for greater regulation of selective passage of mono- and bi-valent salts. The result is a resounding success for the salt separation. In this work, an attempt has been made to study the consequence of salt in gelation bath and interfacial polymerization regarding the behavior of TFC membranes to separate salts from water. The water flux through the polysulfone (Ps) membrane decreases (776.15 LMH to 179.56 LMH) with TDS (salt up to 20000 mg/L. The increase in salt concentration in the aqueous phase (5 to 500 mg/L) of the interfacial reaction influences the salt separation abilities of the TFC membranes. It increases salt separation (Na2SO4 8–9% NaCl 4–6%) by adding 500 mg/L NaCl in piperazine-aqueous solution in different base membranes (Ps-I to Ps-VII). The defluoridation performances of the membranes in accordance with the similar trend as SO4 =. The separation follows the sequence: SO4 = > F− > Cl−. The rejection difference (between Pip-IC and Pip-VIIC) is highest as TDS increases, i.e., TDS: 500 mg/L. The flux reduction is similar (i.e., 30%) as in the case of SO4 = and Cl−.