Ultrafast Graphene Oxide-Lignin Biopolymer Nanocomposite Membranes for Separation of Biomolecules, Dyes, and Salts
Akbar Ali, Muhammad Ismail Vohra, Ahmed Nadeem, Bader Al-Anzi, Muzaffar Iqbal, Ayaz Ali Memon, Ashique Hussain Jatoi, Javeed Akhtar, Jun Yang, Khalid Hussain Thebo
Abstract
Graphene oxide offers a promising opportunity to fabricate highly efficient and pressure-endurable membranes in terms of water permeability while demonstrating a high level of solute rejection. However, achieving higher permeance with an excellent separation capability is still challenging. Herein, we report a class of graphene oxide-lignin biopolymer (GOLB) membranes for the first time prepared by functionalizing GO nanosheets with lignin biopolymer extracted from plant pulp. Lignin biopolymer is the most abundant, green, low-cost, and environmentally friendly material with a variety of oxygen functional groups. The as-prepared GOLB membranes have a unique laminated structure that provides an excellent rejection (>99%) for several organic dyes, proteins, and biomolecules with variable molecular weight and exhibits ultrawater permeance ∼1300 L m –2 h –1 bar –1, more than that of reported GO-based membranes. It is interesting that due to larger interlayer spacing, such membranes show less rejection (<10%) for salts, i.e., NaCl, MgCl 2, Na 2 SO 4, etc. Furthermore, these membranes are highly stable up to 37 days in an aqueous environment and 28 days in acidic and basic solutions compared to pristine GO-based membranes.