Interlayered Thin Film Composite (iTFC) Membranes: The Synthesis and Assembly of Active Layer from Conjugated Microporous Polymer

Authors

Febby Andini, University of Nebraska-LincolnFollow

First Advisor

Dr. Siamak Nejati

Second Advisor

Dr. Tian Zhang

Third Advisor

Dr. Bruce Dvorak

Date of this Version

Fall 12-2-2022

Citation

Febby Andini, University of Nebraska-Lincoln

Comments

A THESIS Presented to Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of the Requirements For the Degree of Master of Science, Major: Environmental Engineering, Under the Supervision of Professor Siamak Nejati. Lincoln, Nebraska: November 2022

Copyright © 2022 Febby Ekamukti Andini

Abstract

The pursuit of advanced materials with well-defined structures at sub-1 nm size, multi-functionalities, and superior chemical stability is essential for enhanced separation performance but technically challenging. Limitations of conventional TFC membranes for use in Organic Solvent Nanofiltration (OSN) can be addressed by manipulating the pore size and chemical properties of the film with novel materials. Conjugated microporous polymers (CMPs) are promising in a few years because of their highly ordered structure and excellent stability. Porphyrin, one of the basic building blocks, can form a conjugated polymer. Herein, poly(5,10,15,20-tetrakis(4-aminophenyl)porphyrin) or PTAPP, is considerably selected as an active layer from CMPs using an electrochemical approach with various processing parameters such as scan rate, monomer concentration, and cycle number. The assembly of electropolymerized PTAPP membranes with or without an interlayer was studied.

The highest separation performance of PTAPP/Nylon membrane using the dense bottom film as the upper layer of the membrane, accounting for 59% of RB-5 dye rejection in methanol and 7.82 L.m^-2.h^-1.bar^-1 methanol permeance. In addition, PTAPP/PE exhibited molecular-sieving selectivity against the mixture of CR and MB dyes and the mixture of CR and MO dyes, with rejection values of 94.48% and 96.16%, respectively. In addition, due to its rigid framework structure of the bottom film, PTAPP/Nylon membrane performed higher NaCl rejection (89%) than the control membrane (53%). Based on SEM characterization, the morphology of poly-TAPP film using MXene as an interlayer revealed the highly porous PTAPP film. However, the pore uniformity, structure, and thickness vary, not strongly correlated with the scan rates.

Advisor: Siamak Nejati