Membrane fouling in reverse osmosis modules leads to a decrease in water purification throughput and an increase in costs for membrane cleaning. Feed spacers ensure a separation of the membrane layers but are also susceptible to fouling. Thus, methods to protect feed spacers e.g. by chemical modification are urgently needed. Especially graphene, as an exciting new material, is an sp2-hybridized carbon allotrope which has been intensively studied. Due to its extraordinary chemical, physical, mechanical and electrical properties, [3, 4] there is much interest in surface applications. Laser-induced graphene (LIG) can be easily generated on different polymer surfaces, using a CO2 laser in an environmentally friendly and cost efficient manner.[5-7] Its surface properties can be easily tailored by post-processing methods such as plasma treatment or chemical modification.[5, 6] The coated feed spacers show very good antifouling properties and even in commercial spiral modules, fouling was substantially reduced. Some of the coatings showed ultrastable plastrons with superior antifouling properties, which offers further potential for future exploration.
Figure 1: Plastron growth on a superhydrophobic LIG surface over 3.5 h using Joule heating. Reprinted from . Students working on this project: Emily Manderfeld [1.] Ahmed, F. E. et al. Electrically conducting nanofiltration membranes based on networked cellulose and carbon nanostructures. Desalination 406, 60–66 (2017).
Collaborations: Prof. Arnusch, Ben-Gurion University of the Negev, Israel
[2.] Kim, Y. C. et al. Adverse impact of feed channel spacers on the performance of pressure retarded osmosis. Environ. Sci. Technol. 46, 4673–4681 (2012).
[3.] Singh, S. P. et al. Laser-Induced Graphene Layers and Electrodes Prevents Microbial Fouling and Exerts Antimicrobial Action. ACS Appl. Mater. Interfaces 9, 18238–18247 (2017).
[4.] Geim, A. K. et al. The rise of graphene. Nat. Mater. 6, 183–191 (2007).
[5.] Manderfeld, E. et al. Electrochemically activated laser-induced graphene coatings against marine biofouling. Appl. Surf. Sci. 569, 150853 (2021).
[6.] Manderfeld, E. et al. Thermoregeneration of Fouling‐Inhibiting Plastrons on Conductive Laser‐Induced Graphene Coatings by Joule Heating. Adv. Mater. Interfaces 9, 2201336 (2022).
[7.] Manderfeld, E. et al. Bacterial surface attachment and fouling assay on polymer and carbon surfaces using Rheinheimera sp. identified using bacteria community analysis of brackish water. Biofouling 38, 940–951 (2022).
Figure 1: Plastron growth on a superhydrophobic LIG surface over 3.5 h using Joule heating. Reprinted from .
Students working on this project: Emily Manderfeld
[1.] Ahmed, F. E. et al. Electrically conducting nanofiltration membranes based on networked cellulose and carbon nanostructures. Desalination 406, 60–66 (2017).