Sustainable Materials for Liquid-Phase Separations in Harsh Environments

  • Abdulaziz Alammar

Student thesis: Phd


Preparing materials into membranes and adsorbents that are stable in harsh environments such as organic solvent nanofiltration requires the use of toxic solvents and aggressive crosslinking procedures. Alternative separation materials are needed to reduce the environmental impact of their manufacturing processes. This thesis explores various renewable materials and green solvents as well as advanced materials such as graphene oxide (GO) and polymer of intrinsic microporosity (PIM-1) to more sustainable and chemically stable membranes and adsorbents. Incorporating small quantities of PIM-1 and GO (i.e., 1 wt%) into the matrix of cellulose acetate (CA) resulted in nanocomposite hydrogels with adsorption capacity as high as 20 mg g−1 and fast kinetic behaviour toward various dilute concentrations of neonicotinoid insecticide pollutants. The adsorption process was optimised so that the prepared hydrogels can be easily regenerated using low-energy ultrasound with high pure water yield (up to 90%). Thin-film composite (TFC) membranes with an ultra-thin selective layer (approx. 30 nm) were successfully prepared via interfacial polymerisation using renewable monomers (i.e., priamine and tannic acid) and green solvent (i.e., p-Cymene and water). The TFC membranes exhibited solvent-resistant property and controllable molecular weight cutoff (MWCO) between 236 and 795 g mol−1 by changing the concentration of the monomers in the interfacial polymerisation process. In addition, nanofiltration membranes were prepared from date seed biomass using a green co-solvent system comprising 1-butyl-3-methylimidazolium acetate and dimethyl sulfoxide. The date seed membranes were chemically stable and promoted successful layering of bio-inspired polydopamine (PDA) coating. The molecular sieving property of the membrane was controlled by increasing the PDA deposition time and deposited layers, which enabled the decrease in the MWCO value as low as 517 g mol−1. Further, optimising the blend of chitosan and cellulose to enhance the compatibility between the two components resulted in solvent-resistance, highly hydrophilic membranes with high separation performance, because of the favourable entanglement of chitosan in between cellulose chains as demonstrated by molecular modelling. The water permeance and oil-removal efficiency were 38 L m−2 h−1 bar−1 and 98.6%, respectively.
Date of Award1 Aug 2023
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorKrishna Persaud (Supervisor)


  • Bio-based Materials
  • Organic Solvent Nanofiltration
  • Membranes
  • Liquid-Phase Separations
  • Sustainability
  • Graphene Oxide

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