Polypiperazine-amide Nanofiltration Membrane Modified by Different Functionalized Multiwalled Carbon Nanotubes (MWCNTs)

Abstract

In this work, three modified multiwalled carbon nanotubes (MWCNTs) with carboxyl (MWCNT-COOH), hydroxyl (MWCNT-OH) and amino groups (MWCNT-NH), respectively, were added into the aqueous phase containing piperazine (PIP) to fabricate the nanocomposite nanofiltration (NF) membranes via interfacial polymerization. The influences of functional groups of MWCNTs on the performance of modified NF membrane were investigated. The MWCNTs were characterized by TEM, FT-IR and TGA; meanwhile, the properties of the membranes were evaluated by XPS, TEM, AFM and contact angle. The XPS results proved the successful incorporation of MWCNT in the active layer of modified NF membrane. When the MWCNT concentration is 0.01% (w/v), all the nanocomposite membranes possessed the optimal separation properties, among which the membrane incorporated with MWCNT-OH demonstrated the highest water flux of 41.4 L·m(-2)·h(-1) and the Na2SO4 rejection of 97.6% whereas the one with MWCNT-COOH had the relative lowest rejection of 96.6%. Furthermore, the increased hydrophilicity of functional groups in modified MWCNTs resulted in different nodular surface morphologies, thicknesses and hydrophilicities of the nanocomposite membranes. All the membranes possessed a molecular weight cutoff (MWCO) within 300 Da and good operation stability.

Mannose‐Modified Multi‐Walled Carbon Nanotubes as a Delivery Nanovector Optimizing the Antigen Presentation of Dendritic Cells

“…After modification with mannosylated ethylenediamine, the peak at 3500 cm −1 decreased and the stretching vibration peak of N−H and C−N appeared at 3200 cm −1 and 1365 cm −1 , intimating the carboxyl was converted to anamide after functionalization. These results were also verified by thermogravimetric analysis (Figure ) and are consistent with similar literature . MWCNTs showed almost no significant weight loss in low temperature, while MWCNTs‐COOH showed one weight loss platform (from 30 °C to 140 °C, 5.395 %) which is due to carboxyl groups.…”

“…These results were also verified by thermogravimetric analysis (Figure 3) and are consistent with similar literature. [30] MWCNTs showed almost no significant weight loss in low temperature, while MWCNTs-COOH showed one weight loss platform (from 30°C to 140°C, 5.395 %) which is due to carboxyl groups. In the curve of Man-MWCNTs, the weight loss is similar to MWCNTs-COOH but slightly increased (from 30°C to 180°C, 6.572 %), indicating that some of the carboxyl groups have been amidated by mannosylated ethylenediamine.…”

SiO2‐modified nanocomposite nanofiltration membranes with high flux and acid resistance

“…An illustration of the forming process of the NF membrane selective layer is shown in Figure S8. The HGPN‐SiO 2 could exist stably in the PA layer with ester bonds formed between hydroxyl groups (HGPN‐SiO 2 ) and acyl chloride groups (TMC) …”

“…The HGPN-SiO 2 could exist stably in the PA layer with ester bonds formed between hydroxyl groups (HGPN-SiO 2 ) and acyl chloride groups (TMC). 25…”

Novel thin‐film nanocomposite membrane with water‐soluble polyhydroxylated fullerene for the separation of Mg2+/Li+ aqueous solution

“…Carbon nanomaterials, dominantly carbon nanotubes (CNTs), graphene oxide (GO) and nanoporous graphene (NPG), have been widely used in NF membranes due to their good separation performance, anti‐fouling properties, and chemical stabilities . They are typically incorporated into NF membranes through IP to form thin‐film nanocomposite (TFN) membranes and thus further enhance the performance of TFC membranes . Zhang et al .…”