Liquid- liquid (Cyclohexanone: Cyclohexanol) separation using augmented tight nanofiltration membrane: A sustainable approach

• Published in: Chemosphere (Oxford) Vol. 355; p. 141820
• Main Authors: Divakar, Swathi, Naik, Nagaraj S., Balakrishna, R. Geetha, Padaki, Mahesh
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-05-2024
• Subjects: Cuprous oxide; Cyclohexanol; Cyclohexanone; Graphitic carbon nitride and polyvinylidene difluoride; Graphitic carbon nitride and polyvinylidene difluoride; Cyclohexanone; Cyclohexanol; Cuprous oxide
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2024.141820

Organic solvent nanofiltration (OSN) is an incipient technology in the field of organic liquid-liquid separation. The incomplete separations and complexity involved in these, forces many organic liquids to be released as effluents and the adverse effects of these on environment is enormous and irreparable. The work prominences on the complete separation of industrially significant cyclohexanone: cyclohexanol (keto-alcohol oil) and heptane: toluene mixtures. The separations of these above-mentioned organic liquid mixtures were carried out using the fabricated Lewis acid modified graphitic carbon nitride (Cu2O@g-C3N4) incorporated polyvinylidene difluoride (PVDF) composite membranes. These fabricated membranes showed a separation factor of 18.16 and flux of 1.62 Lm−2h−1 for cyclohexanone: cyclohexanol mixture and separation of heptane and toluene mixture (with heptane flux of 1.52 Lm−2h−1) showed a separation factor of 9.9. The selectivity and productivity are based on the polarity and size of the organic liquids. The role of Cu2O@g-C3N4 is influencing the pore size distribution, increased divergence from solubility parameters, polarity, solvent uptake and porosity of the composite membranes. The developed composite membranes are thus envisioned to be apt for a wide range of liquid-liquid separations due to its implicit nature.
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•Separation of KA-oil was conducted using Cu2O@g–C3N4–PVDF membranes in an innovative approach for the first time.•Novel molecular sieving with remarkable organic tolerance was demonstrated by Cu2O@g–C3N4–PVDF membranes.•Cu2O@g–C3N4–PVDF membranes displayed a selective separation of cyclohexanone over cyclohexanol.•Significant rejection rate exceeding 95% for cyclohexanone and a separation factor of 18.16.
Synopsis: This study reveals the environmentally benign and a sustainable membrane-based technique avoiding the use of auxiliary solvents for separation and purification that has detrimental effects.