Graphene Oxide-Based Membranes for Water Purification Applications: Effect of Plasma Treatment on the Adhesion and Stability of the Synthesized Membranes

Abstract

The adhesion enhancement of graphene oxide (GO) and reduced graphene oxide (rGO) layer in the underlying polyethersulfone (PES) microfiltration membrane is a crucial step towards developing a high-performance membrane for water purification applications. In the present study, we modified the surface of a PES microfiltration membrane with plasma treatment (PT) carried out at different times (2, 10, and 20 min). We studied the effect of PT on the adhesion, stability, and performance of the synthesized GO/rGO-PES membranes. The membranes’ surface morphology and chemistry were characterized using atomic force microscopy, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. The membrane performance was evaluated by conducting a diffusion test for potassium chloride (KCl) ions through the synthesized membranes. The results revealed that the 2 min PT enhanced the adhesion and stability of the deposited GO/rGO layer when compared to the other plasma-treated membranes. This was associated with an increase in the KCl ion rejection from ~27% to 57%. Surface morphology analysis at a high magnification was performed for the synthesized membranes before and after the diffusion test. Although the membrane’s rejection was improved, the analysis revealed that the GO layers suffered from micro/nano cracks, which negatively affected the membrane’s overall performance. The use of the rGO layer, however, helped in minimizing the GO cracks and enhanced the KCl ion rejection to approximately 94%. Upon increasing the number of rGO deposition cycles from three to five, the performance of the developed rGO-PES membrane was further improved, as confirmed by the increase in its ion rejection to ~99%.

Reduced Graphene Oxide Membranes as Potential Self-Assembling Filter for Wastewater Treatment

“…Recently, innovative systems based on carbon nanotubes, nanofibers, graphene, and graphene oxide have been proposed in the scientific literature, aiming to improve the purification ability with reduced amount of sorbent material [9][10][11]. Although the effectiveness of such novel carbon-based materials is well-known and demonstrated, their use still presents open problems.…”

Graphene Oxide Membranes for Trace Hydrocarbon Contaminant Removal from Aqueous Solution

“…These particular features make them promising as nanofiltration (NF) membranes for ultra-selective separation [ 12 , 13 , 14 , 15 , 16 , 17 ] and water desalination [ 18 , 19 , 20 , 21 ], and also in tubular supports [ 22 , 23 ]. GO membranes are also renowned for their antifouling properties [ 24 , 25 ].…”

Progress and Perspectives of Desalination in China

“…On another hand, novel membrane material synthesis, module design and processing approaches have been broadly explored, rendering the membranes chlorine-resistant, antifouling, stable, and highly efficient in terms of desalination and separation performance. Interested readers are referred to the excellent research and review articles [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. In a recent work by ISDMU and Shandong University of Science and Technology, aminophenyl-modified mesoporous silica NPs were used to fabricate RO membranes, enabling enhanced water flux by 21% while maintaining high NaCl rejection of 98.97%, only slightly decreased by 0.29% compared with that of the pristine membrane [ 47 ].…”