Sustainable Approaches for the Fabrication of Nanocellulose-Polyamide Membrane Based on Waste Date Palm Leaves for Water Treatment

Abstract

A vast amount of agricultural waste, such as dried leaves, stems, pits, seeds, etc., are produced by date palm trees in Saudi Arabia each year. This waste is an excellent source of degradable biomass suitable for many uses. Crystalline nanocellulose (CNC) is one of the most important nanomaterials that can be used in various applications. Due to its unique properties, which include biorenewability, optical transparency, high mechanical strengths, and sustainability, nanocrystalline cellulose has become a significant nanomaterial in recent years. In this study, CNC was isolated from the waste date palm leaves and used for the production of PA-modified membranes for water treatment by reverse osmosis membrane technology. The membranes were prepared by surface polymerization with the polyamide as a selective layer on the polysulfone support film. Three membranes were produced, two with 0.01% and 0.02% (w/v) CNC and the third with PA-free CNC for comparison. Each membrane produced was tested using different characterization techniques. The polyamide membrane with 0.01% w/v CNC had a higher water permeability of 43.25 L/m2 h bar than the membranes with 0% w/v CNC (36.25 L/m2 h) and 0.02% w/v CNC (42.85 L/m2 h bar). Under the same conditions, salt retention was also found to be above 98% for both NaCl and MgSO4 for the two modified membranes. The contact angle was found to be 68.04±3.7, 72.83±0.8, and 63.76±5.5 for PA(0%CNC), PA-CNC (0.01% w/v), and PA-CNC (0.02% w/v), respectively. The 0.01% PA-CNC membrane exhibited a higher water contact angle, greater hydrophobicity and lower surface roughness. As a result, the isolated CNC might be appropriate for use as a modifier agent for membrane fabrication and water treatment.