Original Article:
Unique chemistries of metal-nitrate precursors to form metal-oxide thin films from solution: materials for electronic and energy applications
Palsamy Kanagaraj, et al.
ACS Appl. Mater. Interfaces 2020, 12, 33, 37054–37066.
10.1039/C9TA07727H
Due to the presence of active functional groups such as ester bonds and polar hydroxyl groups, castor oil is considered to be a very valuable renewable bioresource material for industrial applications. The availability of chemical modification of castor oil makes it one of the most important bio-based raw materials in the field of polymer chemistry. A typical modified castor oil is sulfonated castor oil (SCO), in which the ricinoleic acid groups present in hydroxy castor oil are esterified to form the C-O-SO3H groups of SCO.
In this study, the authors prepared a novel sulfonated castor oil-graphene oxide (GO)-reinforced polyetherimide (PEI) membrane through a phase inversion process, which can effectively separate various organic pollutants with excellent long-term antifouling stability.
Effect of Sulfonated Castor Oil in Separation Membrane
- Low-cost, biocompatible, and hydrophilic SCO is used together with graphene oxide (GO) as a hydrophilic material for the hydrophilic modification of polyetherimide (PEI).
- SCO has good compatibility, strong interaction and excellent mechanical support to PEI polymer matrix.
- SCO might be a suitable combination for GO because of the possibility of hydrogen-bonding interactions between the SO3H groups of SCO and the oxygen-containing functional groups of GO. The hydrogen bonding effect can further enrich the mechanical strength, stability, water flux, and antifouling properties of GO-based membranes.
- The increase of surface hydrophilicity and surface negative charge of the SCO/GO composite membrane will help to endow and maintain the high permeability, high separation and long-term antifouling performance of PEI composite ultrafiltration membrane.
Schematic illustration of the inter molecular hydrogen bonding.
Preparation Process of Sulfonated Castor Oil Modified PEI Membrane
In this work, the non-solvent-induced phase separation (NIPS) process was employed to synthesize the membrane.
1. For PEI/SCO membranes, first dissolve SCO in NMP solvent and stir until SCO is completely dissociated in the solvent. Then, slowly add the solvent containing the SCO solution into the solution containing the PEI, immediately raise the temperature to 80° C, stir vigorously at a speed of 2000 rpm, and completely mix the mixed solution to obtain the SCO/PEI casting dope.
2. For the PEI/SCO@GO membrane, GO was first dispersed in NMP solvent, and the pretreatment was completed by heating, stirring and ultrasonic treatment. Then SCO was dissolved in NMP solvent and stirred until SCO was completely dissociated in the solvent. Afterwards, after the uniformly dispersed GO and SCO solution were completely mixed, it was poured into the PEI-containing solution for heating and high-speed stirring to obtain the SCO/GO/PEI casting dope.
3. Use the prepared casting dope for the casting and film forming steps. Membrane pore structure is highly dependent on the relative exchange rates of solvent and non-solvent.
Separation Performance of Sulfonated Castor Oil Modified PEI Membrane
- The water flux (410.6 L m-2h-1) of PEI/SCO@GO membrane is about 50 times that of bare PEI.
- The surface hydrophilicity of the PEI/SCO@GO membrane was significantly increased, and the water contact angle decreased from 98.5° (bare PEI) to 40.4°.
- The separation efficiency of PEI/SCO@GO membrane is greater than 99.0%, especially for oil-in-water emulsion and humic acid solution.
- Comprehensive antifouling performance observed in long-term pollutant filtration cycle analysis.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM8002333 | Sulfonated Castor Oil |  |
8002-33-3 | Price |
