Evaluation of a nanoporous lyotropic liquid crystal polymer membrane for the treatment of hydraulic fracturing produced water via cross-flow filtration

Abstract

Current commercial nanofiltration and reverse osmosis membranes are limited in scope and performance due to their physicochemical properties. Desalination of hydraulic fracturing wastewater poses a particular challenge to membrane filtration given the high concentrations of both organic compounds and salts present in these waters. The recently-developed nanoporous, bicontinuous cubic, lyotropic liquid crystal, thin-film-composite polymer membrane (TFC QI membrane), having unique physicochemical properties, enables an alternative treatment of hydraulic fracturing wastewater. Specifically, the TFC QI membrane recovers the organic compounds from this high-salinity wastewater, enabling biodegradation to occur after desalination. However, other performance criteria must be demonstrated for a membrane to reach application. The work presented herein demonstrates the stable performance of the TFC QI membrane during 66 h of cross-flow filtration of hydraulic fracturing produced water. Compared to the commercial NF90 membrane, the TFC QI membrane recovered a larger portion of the organic compounds, had a higher thickness-normalized water flux, and fouled less. The combination of the TFC QI membrane's selectivity with its reduced fouling propensity makes possible a treatment for hydraulic fracturing wastewater and other complex aqueous streams inaccessible by most commercial membranes, motivating the further study and development of the TFC QI membrane.

Zwitterionic Ion-Selective Membranes with Tunable Subnanometer Pores and Excellent Fouling Resistance

“…13,14 Membranes prepared from polymerized lyotropic liquid crystals (LLCs), for example, possess subnanometer transport channels that retain mono-and divalent ions. 15,16 Block copolymer (BCP) self-assembly has been used to manufacture ultrafiltration (UF) membranes possessing monodisperse pores with controlled functionality 8,13,17−21 but low ion retention due to relatively large pores. To reduce the BCP membrane pore size into the NF regime, 19 researchers utilized block(s) that swell into the pore upon postfunctionalization.…”

“…Self-assembly is a powerful tool for fabricating nanostructured membranes with uniform pore size, controlled surface/pore chemistry, and exceptional performance. , Membranes prepared from polymerized lyotropic liquid crystals (LLCs), for example, possess subnanometer transport channels that retain mono- and divalent ions. , Block copolymer (BCP) self-assembly has been used to manufacture ultrafiltration (UF) membranes possessing monodisperse pores with controlled functionality ,,− but low ion retention due to relatively large pores. To reduce the BCP membrane pore size into the NF regime, researchers utilized block(s) that swell into the pore upon postfunctionalization. − This enabled charge-based separations for ∼1 nm molecules or ∼2 nm pores that remained stable over a broad pH range .…”

Liquid Crystal‐Based Water Treatment Membranes

“…In addition, Dischingeret al [52] demonstrated the crossflow study of this thin film composite Q I membrane as well as its fouling study for the first time. In this study, the authors used this membrane to filter pre-treated produced water using crossflow filtration for 66 h. Further, results revealed that, both in respect of selectivity and thickness-normalized water flux, this membrane exhibited its performance in industrially relevant conditions.…”

Petrochemical wastewater and produced water: Treatment technology and resource recovery

“…A recently developed membrane TFC Q(I) with unique physicochemical properties was tested for its performance in treating hydraulic fracturing produced water using cross-flow filtration (Dischinger, Rosenblum, Noble, & Gin, 2019). The nanoporous lyotropic liquid crystal polymer membrane was effective in recovering organic matter and alleviating fouling.…”