Halloysite Nanotube doped poly lactic acid membrane preparation and seawater desalination: Fid-Bau Portal

Halloysite Nanotube doped poly lactic acid membrane preparation and seawater desalination

Nigiz, Filiz Uğur / Karakoca, Betül

Abstract Halloysite nanotube (Hal) is a natural alumina silicate clay mineral. Hal is used in polymer composites for many reasons such as excellent physical and chemical properties, good miscibility, mechanical strength, antimicrobial properties, and cheapness. It is an important material used in water separation, especially due to its internal and external ionic structure hollow tubular structure. In this study, halloysite was used as a filler in polylactic acid polymer to produce a nanocomposite membrane for seawater purification. The morphological, physical, and chemical structures of the Hal filled, and unfilled membranes were investigated. The effect of HAL content (from 0% to 5% by weight), feed temperature (from 40 °C to 60 °C), NaCl concentration (from 2 wt% to 6 wt%), and the downstream pressure (from 10 mbar to 30 mbar) on the desalination performance were investigated as a function of flux and salt rejection. Hal improved the hydrophilicity, stability, mechanical strength, and the desalination performance of PLA membrane, significantly. The results showed that the highest desalination performance was achieved by 5 wt% of Hal-loaded membrane. The highest flux of 13.14 kg/m².h was obtained accompanied by a rejection of 99.95%. The membrane was also used to purify seawater, and it was found that the permeate's ion concentrations met drinking water standards. The nanocomposite membrane was experimented over 100 h of testing, and no decrease in flux or salt rejection was seen.

Highlights • A Halloysite-polylactic acid membrane was tested for pervaporative desalination. • Halloysite increased the mechanical strength significantly from 4.46MPa to 9.2 MPa. • 13.14 kg/m²h flux and 99.95% NaCl rejection values were obtained. • In all experiments, higher than 99.92% of rejection values were obtained. • Membrane kept its stability during the long-term operating (at least 100 h).