Performance enhancement of thin‐film composite membranes in water desalination process by wood sawdust

Abstract

In this study, polysulfone/wood sawdust (PSf/WSD) mixed matrix membrane (MMM) was prepared as a novel substrate layer of thin‐film composite (TFC) membrane in water desalination. The main aim was to evaluate how different amounts of WSD (0‐5 wt%) and PSf concentrations (12‐16 wt%) in the porous substrate affect the properties of the final TFC membranes in the separation of organic and inorganic compounds. Morphological and wettability studies demonstrated that the addition of small amount of WSD (less than or equal to 1 wt%) in the casting solution resulted in more porous but similar hydrophobic substrates, while high loading (greater than or equal to 2 wt%) of WSD not only changed the substrate wettability and morphology but also increased and decreased the swelling and mechanical properties of substrate layer. Therefore, PA layer formed thereon displayed extensively varying film morphology, interfacial properties, and separation performance. Based on approximately stable permeate flux (ASPF) and apparent salt rejection efficiency (ASRE), the best TFC membrane was prepared over the substrate with 12 to 14 wt% of PSf and around 0.5 to 1 wt% of WSD. Although notable improvements in permeate flux were obtained by adding a small amount of sawdust, the results clearly indicate that the salt rejection mechanism of TFC membrane was different from the glycerin rejection mechanism. Furthermore, durability results of TFC membranes showed that in continuous operation for 30 days, TFC‐14/0.5 and TFC‐14/01 have the maximum plateau levels of stable permeate flux and salt rejection among the all TFC membranes.

Exploring the use of cheap natural raw materials to reduce the internal concentration polarization in thin-film composite forward osmosis membranes

“…Also, the bands in the range of 1000-1300 cm -1 are characteristic of C-O stretching vibration of carboxylic groups in anhydroglucose ring, hemicelluloses and, lignin in both RB and WSD particles. Similar results can be found in the literature [48,60].…”

“…Accordingly, the surface energy and surface hydrophilicity of the WSD-containing membrane has been increased. Recently, the application of WSD as a filler to increase the porosity of SL in the TFC RO membrane was studied [48].…”

Strategies to modify the structure of thin‐film composite membranes for advanced separation of metronidazole antibiotic from wastewater

“…Membrane separation has been introduced as a powerful tool for removing pharmaceutical contaminants 2 . TFC membranes as a new generation of composite membranes have found a special application in drug removal for treating pharmaceutical wastewater thanks to possessing remarkable properties such as high flux 3,4 and high efficiency 5,6 . Meanwhile, thin‐film nano composite membranes, which contain nanoparticles within their structure, have found great popularity in drug separation owing to their excellent properties such as high flux and rejection 7,8 …”

Sawdust based composites

“…Carbon nanotubes were made from sawdust and used to create polypropylene‐based nanocomposites with magnetic properties 15 —while of course other options in making polymer‐based nanocomposites exist 16 . Another original use of sawdust was combining it with polysulfone to create membranes for water desalination 17 …”