Ionic Liquid-Based Colloidal Formulations for the Synthesis of Nano-MOFs: Applications in Gas Adsorption and Water Desalination.

Graphene oxide incorporated thin film nanocomposite nanofiltration membrane for enhanced salt removal performance

To enhance membrane performance of nanofiltration (NF) membranes for dye wastewater treatment, thin film nanocomposite (TFN) membranes embedded with glutamic acid brush modified graphene oxide (GO-GLU) were fabricated. In this current study, GO-GLU was introduced to the selective polyamide (PA) layer which was prepared via interfacial polymerization of organic trimesoyl chloride (TMC) and aqueous m-phenylenediamine (MPD) on a polysulfone (PSF) support. Water permeability and dye rejection with methyl orange (MO) and methylene blue (MB) were used to evaluate membranes performance. The evaluation of TFN membranes via WCA, FTIR, SEM, and AFM demonstrated that GO-GLU nanosheets enhanced hydrophilicity. The fabricated GO-GLU TFN membrane attained a water permeance of 14.11 L/m2h at the optimal GO-GLU dosage of 0.10 wt%, with 99.18% MB rejection and 67.18% MO rejection. Furthermore, it displayed superior antifouling characteristics against Bovine Serum Albumin (BSA) than the virgin TFC membrane and potentially good operation stability performance after 3 cycles. The results proved that addition of GO-GLU nanosheets enhanced membrane performance. The TFN membranes provide excellent performance in effectively removing of dyes from both synthetic and river water samples, rendering them a suitable alternative for wastewater treatment. The study sheds fresh light on the construction of NF membranes by using GO-GLU nanosheets to boost the membranes hydrophilicity and antifouling properties.

Fabrication of polypyrrole-graphitic carbon nitride nanocomposite containing hyper-cross-linked polyamide photoresponsive membrane with self-cleaning properties for water decontamination and desalination applications

A novel double-modified strategy to enhance the performance of thin-film nanocomposite nanofiltration membranes: Incorporating functionalized graphenes into supporting and selective layers

Custom-tailoring metal-organic framework in thin-film nanocomposite nanofiltration membrane with enhanced internal polarity and amplified surface crosslinking for elevated separation property

In-situ coating TiO2 surface by plant-inspired tannic acid for fabrication of thin film nanocomposite nanofiltration membranes toward enhanced separation and antibacterial performance

Thin film nanocomposite (TFN) nanofiltration (NF) membranes were fabricated by incorporating cellulose nanocrystals (CNCs) in a polyamide (PA) layer.

Effect of blending polypyrrole coated multiwalled carbon nanotube on desalination performance and antifouling property of thin film nanocomposite nanofiltration membranes

Thin-film nanocomposite nanofiltration membrane with enhanced desalination and antifouling performance via incorporating L-aspartic acid functionalized graphene quantum dots

Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands in porous structure forms. MOFs have been proposed in use for gas adsorption, purification, and separation applications. This work combines MOFs with 3D printing technologies, in which 3D printed plastics serve as a mechanical structural support for MOFs powder, in order to realize a component design for gas adsorption. The objective of the thesis is to understand the gas adsorption behavior of MIL-101 (Cr) MOF coated on 3D printed PETG, a glycol modified version of polyethylene terephthalate, through a combined experimental and modeling study. The specific goals are: (1) synthesis of MIL-101 (Cr) MOFs; (2) nitrogen gas adsorption measurements and microstructure and phase characterization of the MOFs; (3) design and 3D printing of porous PETG substrate structures; (4) deposition of MOFs coating on the PETG substrates; and (5) Monte Carlo (MC) modeling of sorption isotherms of nitrogen and carbon dioxide in the MOFs.The results show that pure MIL-101 (Cr) MOFs were successfully synthesized, as confirmed by the scanning electron microscopy (SEM) images and X-ray diffrac- tion (XRD), which are consistent with literature data. The Brunauer-Emmett-Teller (BET) surface area measurement shows that the MOFs samples have a high cover- age of nitrogen. The specific surface area of a typical MIL-101 (Cr) MOFs sample is 2716.83 m2/g. MIL-101 (Cr) also shows good uptake at low pressures in experimental tests for nitrogen adsorption. For the PETG substrate, disk-shape plastic samples with a controlled pore morphology were designed and fabricated using the fused de- position modeling (FDM) process. MOFs were coated on the PETG substrates using a layer-by-layer (LbL) assembly approach, up to 30 layers. The MOFs coating layer thicknesses increase with the number of deposition layers. The computational model illustrates that the MOFs show increased outputs in adsorption of nitrogen as pres- sure increases, similar to the trend observed in the adsorption experiment. The model also shows promising results for carbon dioxide uptake at low pressures, and hence the developed MOFs based components would serve as a viable candidate in gas adsorption applications.

This article outlines a sustainable method towards the synthesis of advanced materials such as core/shell Quantum Dots (QDs) and their in situ stabilization using microemulsions (MEs). QDs are versatile materials which show unusual optical properties. We have constructed MEs consisting of an Ionic Liquid (IL) based surfactant i.e. choline dioctylsulfosuccinate, [Cho][AOT] as an emulsifier, toluene as a nonpolar phase and water as a polar phase. The system forms a large single-phase region in the phase diagram without any co-surfactant. Spontaneous formation of micelles has been observed and studied through tensiometry and fluorescence and isothermal titration calorimetry (ITC). The exceptional swelling behaviour of the MEs was studied using Dynamic Light Scattering (DLS) and small angle neutron scattering (SANS). In ME droplets, i.e. Reverse Micelles (RMs), we successfully synthesized spherical core/shell QDs (size ∼3 to ∼6 nm) with precise control over the size and morphology. The QDs have been characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Powder X-ray Diffraction (PXRD). QDs stabilized in MEs exhibited excellent optical properties and can be suitably used as light harvesting materials for diverse applications.

Fabrication of thin film nanocomposite nanofiltration membrane incorporated with cellulose nanocrystals for removal of Cu(II) and Pb(II)

Sulfonated graphene oxide incorporated thin film nanocomposite nanofiltration membrane to enhance permeation and antifouling properties

In order to develop a high-performance thin-film nanocomposite (TFN) nanofiltration (NF) membrane, the functionalized graphene-based nanomaterial (GO-HBE-COOH) was synthesized by combining two-dimensional graphene oxide (GO) with a three-dimensional hyperbranched polymer, which was used as the novel nanofiller and successfully embedded into the polypiperazine-amide (PPA) active layers on polysulfone (PSU) substrates via interfacial polymerization (IP) process. The resultant NF membranes were characterized using ATR-FTIR, SEM, and AFM, while their performance was evaluated in terms of water flux, salt rejection, antifouling ability, and chlorine resistance. The influence of GO-HBE-COOH concentration on the morphologies, properties, and performance of TFN NF membranes was investigated. With the addition of 60 ppm GO-HBE-COOH, the TFN-GHC-60 NF membrane exhibited the optimal water flux without a sacrifice of the salt rejection. It was found that the introduction of GO-HBE-COOH nanosheets favored the formation of a thinner and smoother nanocomposite active layer with an enhanced hydrophilicity and negative charge. As a result, TFN NF membranes demonstrated a superior permeaselectivity, antifouling ability, and chlorine resistance over the conventional PPA thin-film composite (TFC) membranes.

Thin film nanocomposite (TFN) membranes contain nanoparticles in the thin polyamide (PA) top layer, resulting in a remarkable increase in water permeability without compromising the salt rejection. Mesoporous silica nanoparticles (MSN) have gained much attention as nanofillers for improved performance PA TFN membranes. However, aggregation of MSN inside the PA layer and their tendency to fast dissolution in aqueous solutions are serious challenges which strongly affect the separation performance of MSN-based TFN membranes. In this work, these challenges were addressed by controlling the functionalization of MSN with hydrophobic organo-silane, such as octadecyltrichlorosilane (OTS) or methyltrichlorosilane (MTS), before incorporating in the PA layer. MSN were synthesized first by sol-gel process and then functionalized using post-grafting method during silanization reaction. The functionalization was tuned in order to allow the hydrophobic alkyl group of the silane molecule to graft both the external surface of MSN as well as their interior pores or to modify only their external surface depending on the functionalization procedure and the silane concentration. The model of functionalization and the amount of OTS or MTS grafted on the surface were estimated through the nitrogen adsorption measurement and thermogravimetric analysis. The functionalized MSN with a particle diameter of ≈ 80 nm were thereafter easily dispersed in the organic solvent during the TFN membrane preparation via interfacial polymerization method. The membrane performance was then assessed based on water permeability and salt rejection measurements. Several parameters were found to have a strong influence on the membrane performance such as concentration of grafted OTS or MTS and the NPs loading inside the PA layer. The low aggregation and good integration of the functionalized nanofillers inside the PA layer produced TFN membranes with superior initial water permeability. The results revealed that the initial water permeability of the TFN membranes with OTS functionalized MSN achieved ≈ 65% higher initial permeability than the reference TFC membrane at the optimum OTS amount and NPs loading, without sacrificing the membrane selectivity. Whereas the corresponding TFN membranes with MTS functionalized MSN achieved ≈ 130% higher permeance but with 2% less salt rejection than the reference TFC membrane at the same conditions. The controlled functionalization of MSN nanofillers not only can improve membrane performance but also can provide a deeper understanding of the role of porous structure of MSN on the separation mechanism. This work clearly emphasizes the direct relationship between the internal pores of MSN inside the PA barrier layer and increasing or decreasing the water permeability of resulting TFN membranes. Furthermore, it was investigated, how hydrophobic functionalization of MSN can improve the stability of MSN in aqueous solutions and improve the stability of the respective TFN membranes over prolonged filtration time at different pH values. The results showed that TFN membranes containing the OTS-functionalized MSN had only ≈ 6% (or 7.5% for MTS-functionalized MSN) decline in salt rejection compared to 34.5% decline for the membrane containing unfunctionalized nanofillers accompanied by increasing in water permeability after 240 h filtration time (120 h at pH 5 then 120 h at pH 9). According to these results, it was concluded that the functionalized MSN have low dissolution tendency due to the formation of a protective organic layer leading to enhanced long-time stability of the TFN membranes. Finally, the durability of the barrier layer after a prolonged use for desalination performance of PA TFN membranes was also investigated.