CNTs Intercalated LDH Composite Membrane for Water Purification with High Permeance

Abstract

The pursuit of improved water purification technology has motivated extensive research on novel membrane materials to be carried out. In this paper, one-dimensional carboxylated carbon nanotubes (CNTs) were intercalated into the interlayer space of layered double hydroxide (LDH) to form a composite membrane for water purification. The CNTs/LDH laminates were deposited on the surface of the hydrolyzed polyacrylonitrile (PAN) ultrafiltration membrane through a vacuum-assisted assembly strategy. Based on the characterization of the morphology and structure of the CNTs/LDH composite membrane, it was found that the intercalation of CNT created more mass transfer channels for water molecules. Moreover, the permeance of the CNTs/LDH membrane was improved by more than 50% due to the low friction and rapid flow of water molecules in the CNT tubes. Additionally, the influence of preparation conditions on the separation performance was investigated using Evans blue (EB). Optimized fabrication conditions were given (the concentration of CoAl-LDH was 0.1 g/L and the weight ratio of CNTs was 2 wt.%). Next, the separation performances of the prepared CNTs/LDH composite membrane were evaluated using both single and mixed dye solutions. The results showed that the composite membrane obtained possessed a retention of 98% with a permeance of 2600 kg/(m2·h·MPa) for EB, which was improved by 36% compared with the pristine LDH composite membrane. Moreover, the stability of the CNTs/LDH composite membrane was investigated in 100 h with no obvious permeance drop (less than 13%), which exhibited its great potential in water purification.

Modification of pristine layered double hydroxide to form metal oxide composites as an anionic dye photodegradation catalysts

“…It is potential for LDH application if it has the same basic/pristine structure with another research field. Researches on the application of LDHs, among others, Mg/Al LDH in polyether sulfonate as energy storage device [6], Co/Al LDH in polyacrylonitrile for water purification [7], and PEG-Mg/Al LDH-FeO as material carrier for sorafenib was an anti-liver cancer drug [8]. In this case, MgPd/Al LDH was as a glycerol hydrogenolysis reaction catalyst [9] and Mg/AlAu LDH was as a nitrophenol hydrogenation catalyst [10].…”

Recent Advances in Layered‐Double‐Hydroxide‐Based Separation Membranes

“… [34] Among them, the Gly‐MgAl‐LDHs membrane exhibited a permeance of 566 L/m 2 ⋅ h ⋅ MPa and a rejection rate of 98 % for negatively charged dyes. Subsequently, LDHs membranes intercalated with different molecular clusters, such as iron cages, [34] carbon nanotubes, [35] and SiW 12 , [36] were used for dye removal and desalination. Additionally, the uniform distribution of hydroxyl groups on the surface can be utilized to achieve high water flux (Figure 6B).…”

Surface Charge Modification on 2D Nanofluidic Membrane for Regulating Ion Transport

“…In contrast, the GO/LDH/GO composite membrane exhibited superior stability in water for at least five days. Li et al [149] inserted carboxylated CNTs into the nanochannels of LDH membranes, creating abundant low-friction mass transfer channels for water molecules and increasing the permeability of the composite membranes by more than 50%. Wang et al [150] fabricated Fe-cages(metal-organic polyhedral)embedded LDH composite membranes based on polyacrylonitrile membranes (Figure 19a).…”

“…Li et al. [ 149 ] inserted carboxylated CNTs into the nanochannels of LDH membranes, creating abundant low‐friction mass transfer channels for water molecules and increasing the permeability of the composite membranes by more than 50%. Wang et al.…”