Hyperbranched Polyethylenimine Research Articles

High-efficiency and economical uranium extraction from seawater with easily prepared supramolecular complexes

Developing effective adsorbents for uranium extraction from natural seawater is strategically significant for the sustainable fuel supply of nuclear energy. Herein, stable and low-cost supramolecular complexes (PA-bPEI complexes) were facilely constructed through the assembly of phytic acid and hyperbranched polyethyleneimine based on the multiple modes of electrostatic interaction and hydrogen bonding. The PA-bPEI complexes exhibited not only high uptake (841.7 mg g−1) and selectivity (uranium/vanadium selectivity = 84.1) toward uranium but also good antibacterial ability against biofouling. Mechanism analysis revealed that phosphate chelating groups and amine assistant groups coordinated the uranyl ions together with a high affinity. To be more suitable for practical applications, powdery PA-bPEI complexes were compounded with sodium alginate to fabricate various macroscopic adsorbents with engineered forms, which achieved an extraction capacity of 9.0 mg g−1 in natural seawater after 50 days of testing. Impressively, the estimated economic cost of the macroscopic adsorbent for uranium extraction from seawater ($96.5 ∼ 138.1 kg−1 uranium) was lower than that of all currently available uranium adsorbents. Due to their good uranium extraction performance and low economic cost, supramolecular complex-based adsorbents show great potential for industrial uranium extraction from seawater.

Carbon Nanodisks Decorated with Guanidinylated Hyperbranched Polyethyleneimine Derivatives as Efficient Antibacterial Agents.

Non-toxic carbon-based hybrid nanomaterials based on carbon nanodisks were synthesized and assessed as novel antibacterial agents. Specifically, acid-treated carbon nanodisks (oxCNDs), as a safe alternative material to graphene oxide, interacted through covalent and non-covalent bonding with guanidinylated hyperbranched polyethyleneimine derivatives (GPEI5K and GPEI25K), affording the oxCNDs@GPEI5K and oxCNDs@GPEI25K hybrids. Their physico-chemical characterization confirmed the successful and homogenous attachment of GPEIs on the surface of oxCNDs, which, due to the presence of guanidinium groups, offered them improved aqueous stability. Moreover, the antibacterial activity of oxCNDs@GPEIs was evaluated against Gram-negative E. coli and Gram-positive S. aureus bacteria. It was found that both hybrids exhibited enhanced antibacterial activity, with oxCNDs@GPEI5K being more active than oxCNDs@GPEI25K. Their MIC and MBC values were found to be much lower than those of oxCNDs, revealing that the GPEI attachment endowed the hybrids with enhanced antibacterial properties. These improved properties were attributed to the polycationic character of the oxCNDs@GPEIs, which enables effective interaction with the bacterial cytoplasmic membrane and cell walls, leading to cell envelope damage, and eventually cell lysis. Finally, oxCNDs@GPEIs showed minimal cytotoxicity on mammalian cells, indicating that these hybrid nanomaterials have great potential to be used as safe and efficient antibacterial agents.

Bio-functionalized carbon dots for signaling immuno-reaction of carcinoembryonic antigen in an electrochemical biosensor for cancer biomarker detection

Early diagnosis of cancer demands sensitive and accurate detection of cancer biomarkers in blood. Carbon dots (CDs) bio-functionalization with antibodies, peptides or aptamers have played significant role in cancer diagnosis and targeted cancer therapy. Herein, a biosensor for detection of cancer biomarker carcinoembryonic antigen (CEA) in blood serum has been designed using CDs bio-functionalized with HRP-conjugated CEA antibody (CUCDs@CEAAb2) as detection probe. CDs were synthesized by upscaling of cow urine, a nitrogen rich biomass waste, by hydrothermal method. Detection probe based on CDs resulted in 3.5 times higher sensitivity as compared to conventional electrochemical sandwich immunoassay. To further improve the sensor performance, hyper-branched polyethylenimine grafted poly amino aniline (PEI-g-PAANI) was used as the sensing interface, which enabled immobilization of higher amount of capture antibody. Detection of CEA in human blood serum coupled with wide linear range (0.5–50 ng/ml), good specificity, stability, reproducibility and low detection limit (10 pg/ml) signified the excellence of CUCDs based CEA immunosensor. CUCDs exhibited excitation wavelength dependent fluorescence property and showed strong blue emission under UV irradiation. MTT assay indicated that the material is not toxic towards human dental pulp stem cells (hDPSCs) and MG63 osteosarcoma cells (cell viability > 90%). The present study demonstrates a methodology for valorization of animal waste to a cost-effective carbon based functional nanomaterial for clinical detection of cancer biomarkers.

Hyperbranched-Polyethylenimine-Functionalized Coal Fly Ash as an Adsorbent for the Removal of Hexavalent Chromium and Reuse as a Dye Photocatalyst.

Coal fly ash (CFA) has been extensively researched as an adsorbent for heavy metals, but its application is limited by its low adsorption capacity. The modification of CFA with hyperbranched polymers results in improved adsorption capacities. Hyperbranched polyethylenimine (HPEI) is a hyperbranched polymer containing NH2 groups that can bind with heavy metal ions through complexation or electrostatic interactions. In this study, CFA-HPEI adsorbents with various HPEI loadings (1-5%) were prepared and evaluated for the removal of Cr(VI). The successful incorporation of HPEI onto CFA was confirmed using Fourier transform infrared, elemental analysis, and X-ray photoelectron spectroscopy (XPS). The 3% CFA-HPEI loaded adsorbent resulted in optimum results when the effect of pH and adsorbent dosage was studied. The pseudo-second-order kinetics model best described the adsorption kinetics at an initial concentration of 20 mg/L. The Freundlich adsorption isotherm model best fitted the equilibrium adsorption data with a maximum adsorption capacity of 85.93 mg/g. The Cr-loaded adsorbent was reused as a photocatalyst to degrade methylene blue (MB) in the presence of visible light. The loaded adsorbent degraded 98.9% of MB (5 mg/L) within 180 min and was accompanied by compounds with m/z of 173 and 234, corresponding to the intermediate degradation of Azure A. The XPS analysis confirmed the coexistence of Cr(III) and Cr(VI) on the surface of the adsorbent. In addition, the loaded adsorbent exhibited good stability following MB degradation with no structural changes observed. Thus, CFA-HPEI adsorbents can be utilized as low-cost adsorbents for the remediation of toxic Cr(VI) from water and wastewater. The Cr-loaded CFA-HPEI adsorbent can be effectively reused as a photocatalyst, thus reducing environmental pollution.

Terminal amine‐based hyperbranched polymer‐modified metal oxide particles for improving the stability of water‐based drilling fluids in interaction with shales

AbstractWhen oil and gas extraction is drilled into water‐sensitive shale formations, water intrusion leads to hydration expansion and dispersion of shale clay minerals, which in turn leads to well wall instability. Two nanomaterials, PET and PEF, were synthesized using Hyperbranched polyethyleneimine (HPEI) as shell‐coated metal oxide nanoparticles (MONPs), and the nanomaterials were characterized in terms of molecular structure, thermal stability, and particle size distribution. The blocking and inhibition properties of PET and PEF were tested and investigated by analytical methods such as linear swelling experiments, shale rock chip rolling recovery experiments, and American Petroleum Institute (API) filtration loss experiments, the effects of PET and PEF on the rheology and filter loss reduction of water‐based drilling fuilds (WBDFs) were also investigated. PET and PEF have good blocking and inhibition properties, which somewhat ameliorate the effect of NPs on the rheology of WBDFs, while significantly improving the stability of shale in WBDFs.

Preparation of polyamine loofah cellulose and its adsorption for reactive brilliant red K–2BP

In this paper, a novel efficient dye adsorbent, functional loofah cellulose (FL) was successfully prepared using loofah cellulose as matrix and hyperbranched polyethylenimine(HBPEI) as functionalizing reagent. Its structure was characterized by various tools. The adsorption behavior of FL to reactive brilliant red K–2BP was further discussed under different pH, different amounts of adsorbent, and interfering ion intensity. The results showed that the adsorption process belonged to Langmuir's isothermal adsorption. When the initial concentration of dye was 500 mg/L, the maximum saturated adsorption capacity was 1552 mg/g. The adsorption process conforms to the quasi-second-order adsorption kinetics and belongs to spontaneous adsorption. In addition, FL has excellent recycling and regeneration ability.

Dielectric Analysis of Blended Polysulfone/Polyethylenimine Membrane Contactors for CO2 Capture.

Polysulfone membranes, used as contactors for CO2 capture, are blended with two different hyperbranched polyethyleneimines modified with benzoyl chloride (Additive 1) and phenyl isocyanate (Additive 2) in different percentages. Fourier-transformed infrared spectra evidence the presence of urea and amide groups, whereas the field emission scanning electron microscopy images show differences in the microstructure of the blended membranes. Dielectric spectra determine the motions of the side and backbone chains, which can facilitate the diffusion of CO2 . The spectra consist of six dielectric processes; three of them are due to the polysulfone (γPSf , βPSf , and αPSf ), whereas the rest are characteristic of the additive (γHPEI , βHPEI , and αHPEI ). The benzoyl chloride and phenyl isocyanate functional groups introduce variations in molecular mobility and modify the relaxations associated with the hyperbranched polyethyleneimine (HPEI). The additives also increase the conductivity of the blended membranes, which can compromise the performance of the membranes, specifically in the case of Additive 1. Ion hopping is found to be the prevailing charge transport mechanism while both relaxations, αHPEI and αPSf , are actives. These results, together with the final morphology of the membranes, may explain the greater absorption capacity of the membranes prepared with the hyperbranched polyethyleneimine modified with Additive 2.

Demulsification efficiency and mechanism of hydrophobic carbon chains modified hyperbranched polyethylenimide on oil-in-water emulsion

A series of amphiphilic hyperbranched polyethylenimine (HPEI-Cn) with different length hydrophobic carbon chains were synthesized by amidation modification of hyperbranched polyethylenimine (HPEI), which can be used for separation of oil-in-water emulsion. The demulsification effect of HPEI-Cn under different demulsifier concentration, temperature, settling time and pH value were evaluated by bottle test method. The results indicated that the demulsification efficiency (DE) of HPEI-Cn increased with the increase of graft length of carbon chain. Encouragingly, the HPEI-C16 had the characteristics of small amount (50 mg/L), short settling time (30 min) and wide temperature adaptation range (20–60 °C). Through three-phase contact angle tests (CA), dynamic interfacial tension tests (IFT), elastic modulus analysis, Zeta potential and microscope observation, the demulsification mechanism of HPEI-Cn was systematically revealed. The excellent DE of HPEI-C16 was attributed to the high interfacial activity and appropriate length of hydrophobic groups. On the one hand, the high interfacial activity drives hyperbranched macromolecules to rapidly diffuse and adsorb to the oil-water interface. On the other hand, it contains appropriate hydrophobic carbon chains C16 to flocculate and coalesce oil droplets, thus achieving efficient demulsification.

Dendronized Hyperbranched Polyethyleneimines with Switchable Thermoresponsiveness and Encapsulation

AbstractHyperbranched polyethyleneimines (PEIs) with multiple layered structures and high density of terminal amino groups have shown great potential for applications in biomedicine, sensors, and catalysis. In this work, a kind of dendronized hyperbranched PEIs (DHPs) is synthesized by modification of PEIs with dendritic oligoethylene glycols (OEGs). These DHPs not only inherit the characteristic thermoresponsive behavior from the OEG dendrons, but also show low cytotoxicity and switchable encapsulation capacities. Their thermoresponsive behavior is found to be mainly dependent on the coverage and amphiphilicity of dendritic OEGs, solution pH, and NaCl concentration. Moreover, DHPs exhibit advantages in thermally‐switchable complexation with guest molecules because of their adjustable crowding effect from the densely packed OEG chains. In addition, these DHPs can also be used as nanoreactors, which can reduce metal ions into metal nanoparticles in a convenient way. In virtue of these peculiarities, it is believed that these dendronized hyperbranched PEIs with smart properties can be used as promising scaffolds in drug‐controlled release and nanoreactors.

Fabrication of wood-inspired nanocellulose-based aerogels for efficient adsorption and filtration removal of Congo red

Nanocellulose aerogels have received considerable attention as environmentally friendly adsorption materials for dye wastewater treatment. However, it remains challenging to prepare nanocellulose aerogels with excellent mechanical properties, efficient and fast dye separation, and recyclability. Inspired by the wood structure, this study developed an anisotropic aerogel absorbent by modifying nanocellulose using polyethylene glycol diglycidyl ether (PEGDE) and hyperbranched polyethyleneimine (HPEI), and subsequent directional freezing. The double physical-chemical cross-linked and oriented porous structure in the aerogel enhanced the mechanical properties, leading to high compressive strength and rapid resilience. The HPEI modification provided abundant adsorption sites for dye adsorption, and the directional pore structure shortened the flow path of the dye, resulting in a maximum adsorption capacity up to 3149.61 mg/g for Congo red solution at an initial concentration of 400 mg/L, which was considerably higher than the reported adsorption capacities of similar adsorbents. The anisotropic nanocellulose aerogel also exhibited excellent recyclability, maintaining a dye removal rate of 96.88% or higher after eight cycles. Furthermore, a continuous s separation device was designed based on the anisotropic nanocellulose aerogel and real-time purification of dye wastewater was achieved through filtration under gravity. Therefore, the nanocellulose aerogels developed in this study show great potential for efficient purification of textile printing and dyeing wastewater.

Enhancing and toughening bamboo interfacial bonding strength by reactive hyperbranched polyethyleneimine modified phenol formaldehyde resin adhesive

Phenol formaldehyde (PF) resin adhesives are widely used in the production of bamboo-based composites owing to their excellent bonding strength and durability. However, the inherent brittleness of cured PF resin may result in notable stress concentration at the interface between PF resin and bamboo bonding, leading to the generation of cracks. In this study, a hyperbranched compound polyethyleneimine (PEI) with high reaction activity was incorporated into a PF resin adhesive to toughen the adhesive and the bonding interface. And the effects of PEI incorporation on the properties of the adhesive and the bonding performance between PF resin and bamboo were comprehensively investigated. The results showed that introduction of flexible PEI chains could effectively facilitated stress transfer, avoiding stress concentration, thus enabling efficient energy release and play a toughening effect. In addition, PEI could react with PF resin and bamboo components during hot pressing, forming a three-dimensional network structure and enhancing the bonding interface, which was proved by FT-IR and XPS analysis. When 1 wt% PEI was incorporated, the bending strength and Charpy impact toughness of the modified PF resin was significantly increased by 38.88% and 76.02%, respectively, compared with the pure PF resin. While the dry and wet shear strength of the bamboo composite bonded by the PEI modified PF resin were also obviously increased. This study is expected to address the problem of cracking in the bonding interface of bamboo composite, and endow the composites with high strength and durability, which can prolong its service life and contribute to the healthy and sustainable development of the bamboo industry.

Designing pectin and hyperbranched polyethylene imine based hydrogel for the removal and adsorption of ionic dyes

In this study, we developed pectin based hydrogel modified with hyperbranched polyethylene imine integrated with graphene oxide as a filler for the removal of cationic and anionic dyes. Moreover, in this paper, we also studied dynamic adsorption capacity of hydrogel towards crystal violet dye. Graphene oxide was first prepared by the Hummers method. The result in this study illustrated that dynamic adsorption capacity of hydrogels enhanced with increase in GO concentration up to 192 mg g−1 this might be ascribed to the increase in active groups along with porosity created in hydrogel structure. Moreover, the change in parameters such as pH, salt concentration, flux rate and concentration of dye showed promising results. Hence the pectin based hydrogels have great potential for eradication of dyes.

Fabrication of high-performance MeI and HPEI assembled PES/CPES hollow fiber nanofiltration membranes with high positive charges for efficient removal of salt/heavy metal ions

Environmental protection and resource recovery require efficient separation of salts and heavy metal ions from wastewater. A new hollow fiber nanofiltration membrane (HFNM) with a highly positive charge was developed via Hyperbranched polyethyleneimine (HPEI) self-assembly and methyl iodide (MeI) quaternization on a polyethersulfone (PES) with carboxylic-PES (CPES) substrate. Effects of different layers on surface charge and roughness, wettability, and mechanical stability were evaluated. MgCl2 and ZnCl2 as representative of salts and heavy-metal ions, respectively, were used to investigate separating properties of the membranes in terms of feed temperature and concentrations, operating pressures, antifouling properties, and long-term stability. The relationship between salt/ions rejection and water flux, pore size, and surface positive charge degree was explained by comparing the structures and properties of the membranes. The 1wt.% HPEI and 0.5 wt.% GA solutions for 30 min crosslinking at pH of 11 and then 5 wt.% MeI solution could lead to the formation of the optimum membrane. Based on high hydrophilicity, low surface roughness, Donnan exclusion, and steric hindrance, the membrane could effectively exhibit superb rejection rates of Zn2+ (99.8 %), and Mg2+ (98.6 %), while showing high flux values (24.47 and 33.54 Lm−2h−1). The high flux rate (around 25.41 Lm−2h−1) during 4 cycles of regeneration, and high ions rejection (>98 %) were retained even after an 8-hour consistent operation. The prepared membrane, with high durability and structural stability, can introduce an effective solution for water purification from divalent ions.

Amide-decorated carbon dots as sensitive and selective probes for fluorescence enhancement detection of cadmium ion

As highly toxic metal ions, cadmium ions (Cd2+) are prevalent in varying concentrations around the world. The establishment of an accurate and effective method for Cd2+ determination with high sensitivity and selectivity is of particular concern. The present work fabricated a fluorescence chemosensor for the detection of Cd2+ based on functionalized carbon dots (CDs), which were hydrothermally prepared using amidated hyperbranched-polyethyleneimine (HPEI). As investigated by FTIR, NMR, and XPS, the stably grafted amide groups endowed the CDs with thermosensitivity and high cloud point due to the change in hydrophilic-hydrophobic behaviors. The CDs chemosensor with optimal amidation degree exhibited high sensitivity, selectivity, and stability in the determination of Cd2+ from various water environments. Notably, the fluorescence intensity enhanced with the increase of Cd2+ concentration, originating from the improved structure rigidity caused by the interactions between grafted amides and Cd2+. These impressive features made the CDs not only sensitive to detecting Cd2+ in low-concentration solutions with a limit of detection of 3.41 nM (the lowest known value for Cd2+ detection) but also accurate for the quantification in high-concentration solutions with a detectable Cd2+ concentration of 6.0 × 10−2 M. Owing to the broad detection range, the CDs developed in present work show great potential applications in various scenarios.

Employing sulfolane as a green solvent in the fabrication of nanofiltration membranes with excellent dye/salt separation performances for textile wastewater treatment

This study explores the potential use of sulfolane, a green and sustainable solvent, as an alternative to toxic solvents in the fabrication of high-performance nanofiltration membranes. A comparison of Hansen solubility parameter (HSP) with N-methyl-2-pyrrolidone (NMP) indicates that sulfolane is a “poor” solvent for the sulfonated polyphenylenesulfone (sPPSU) polymer, which results in a lower critical polymer concentration (CPC) required to produce a macrovoid-free membrane structure. Moreover, the addition of a low molecular weight hyperbranched polyethyleneimine (HPEI) of MW = 800 g/mol as a crosslinker enhances the mechanical rigidity of the membranes without affecting the pore structure required for retaining salts from dye/salt mixtures, enabling practical applications in wastewater treatment. Notably, the membranes demonstrate exceptional dye/salt separation performance with a separation factor SDye/Salt of up to 69.32, even for low molecular weight dyes as low as 268 g/mol (i.e., a Disperse blue 1 and Na2SO4 mixture). To the best of our knowledge, this is the lowest MW dye ever tested for dye/salt separation. The membranes also show good antifouling capability over an extended period of use. Literature comparison shows that the sPPSU/sulfolane membrane crosslinked with HPEI800 for 60 min, referred to as sPSlf-c60, exhibits superior dye/salt separation performance, indicating their potential for the treatment of textile wastewater effluents.

A novel PAN/GO electrospun nanocomposite fibrous membranes with rich amino groups for highly efficient adsorption of Au(III)

The wastewater containing Au(III) is directly discharged into the natural environment, resulting in a serious waste of resources and pollution of water environment. Therefore, it has profound significance to efficiently remove and recover Au(III) from industrial wastewater. Hyperbranched polyethyleneimine (HPEI), as a non-toxic polymer, rich in primary and secondary amine groups, which have strong affinity for metal ions. However, the application of HPEI as an adsorbent in water system is limited by the fact that it is water-soluble and difficult to separate and recover. In this study, using graphene oxide (GO) grafted with HPEI as additive and polyacrylonitrile (PAN) as matrix, PAN/GO-HPEI electrospun nanocomposite fibrous membranes were synthesized by electrospinning, and then grafted with HPEI by chemical graft reaction to obtain HPEI-g-PAN/GO-HPEI electrospun nanocomposite fibrous membranes, which were employed as adsorbent to adsorb Au(III) in aqueous solution. Benefitting from the existence of rich amino groups in the HPEI-g-PAN/GO-HPEI, the HPEI-g-PAN/GO-HPEI had highly efficient adsorption for Au(III) and the maximum adsorption capacity was 2893.33 mg·g−1. Significantly, the adsorbed Au(III) could be reduced to Au(I) and irregular flakes and granular Au elemental attached to the adsorbent in the adsorption process. Moreover, the HPEI-g-PAN/GO-HPEI had excellent adsorption selectivity for Au(III). Therefore, the HPEI-g-PAN/GO-HPEI has potential applications as a promising adsorbent for highly efficient recovery of Au(III) in wastewater.

Polyethyleneimine-cured epoxy-based solvent tolerant nanofiltration membranes

Epoxy-based nanofiltration (NF) membranes have great potential to allow untapped applications such as the treatment of water/solvent mixtures. However, achieving reproducible membrane performance with concurrent high permeances for water/solvent mixtures and high solute rejections remains challenging. Herein, such a solvent-tolerant NF (STNF) membrane with superior performance characteristics is synthesized through optimizing the non-solvent induced phase separation (NIPS) method by simultaneously curing 2 epoxide building blocks (EPON 1009F (20 wt%) and EPON SU-8 (10 wt%)) with hyperbranched polyethylene imine (PEI) in dimethyl sulfoxide (DMSO). As a multifunctional crosslinker, the hyperbranched PEI, compared to the difunctional linear hexane diamine (HDA), increases the synthesis reproducibility, the membrane flexibility and permeability, offering a remarkable water/DMF (80/20) permeance of 5.7 L m-1 h-1 bar-1 and a rejection of rose bengal (1018 g mol−1) of 93.3%. A decreased permeance and rejection was observed when increasing the solvent content in the water/DMF or water/ethanol feed from 0 to 30 wt%, while a change in water permeance occurred before and after water/solvent filtrations. The epoxy-based membrane is also intrinsically stable in many solvents, and is easy to tune and produce, making it an ideal candidate for the purification of solvent-containing wastewaters from e.g., the pharmaceutical and chemical industries.

Advanced Binary Guanosine and Guanosine 5'-Monophosphate Cell-Laden Hydrogels for Soft Tissue Reconstruction by 3D Bioprinting.

Soft tissue defects or pathologies frequently necessitate the use of biomaterials that provide the volume required for subsequent vascularization and tissue formation as autrografts are not always a feasible alternative. Supramolecular hydrogels represent promising candidates because of their 3D structure, which resembles the native extracellular matrix, and their capacity to entrap and sustain living cells. Guanosine-based hydrogels have emerged as prime candidates in recent years since the nucleoside self-assembles into well-ordered structures like G-quadruplexes by coordinating K+ ions and π-π stacking, ultimately forming an extensive nanofibrillar network. However, such compositions were frequently inappropriate for 3D printing due to material spreading and low shape stability over time. Thus, the present work aimed to develop a binary cell-laden hydrogel capable of ensuring cell survival while providing enough stability to ensure scaffold biointegration during soft tissue reconstruction. For that purpose, a binary hydrogel made of guanosine and guanosine 5'-monophosphate was optimized, rat mesenchymal stem cells were entrapped, and the composition was bioprinted. To further increase stability, the printed structure was coated with hyperbranched polyethylenimine. Scanning electron microscopic studies demonstrated an extensive nanofibrillar network, indicating excellent G-quadruplex formation, and rheological analysis confirmed good printing and thixotropic qualities. Additionally, diffusion tests using fluorescein isothiocyanate labeled-dextran (70, 500, and 2000 kDa) showed that nutrients of various molecular weights may diffuse through the hydrogel scaffold. Finally, cells were evenly distributed throughout the printed scaffold, cell survival was 85% after 21 days, and lipid droplet formation was observed after 7 days under adipogenic conditions, indicating successful differentiation and proper cell functioning. To conclude, such hydrogels may enable the 3D bioprinting of customized scaffolds perfectly matching the respective soft tissue defect, thereby potentially improving the outcome of the tissue reconstruction intervention.

Carbon-supported statistically distributed polyethyleneimine/palladium (II) complexes as efficient and sustainable Sonogashira catalysts

A novel approach toward the obtaining of a Pd (II) carbon-supported catalyst based on a statistical distributed polymer (hyperbranched polyethyleneimine) and its use as a highly efficient and sustainable catalyst for Sonogashira-type coupling reactions is presented. The heterogenous Pd (II)/HBPEI catalyst fabricated through a facile, cost-effective and scalable procedure provides an innovative catalyst structure based on statistical distributed singular catalytic centers with well-defined Pd-Polymer chemical interactions, highly resistant to suffer leaching processes and extensively and homogenously distributed across the whole carbon surface. The catalyst exhibited excellent catalytic and recycling activity for several cross-coupling reactions between different aryl halides and terminal alkynes, free of any undesired by-product and in excellent yields, under air atmosphere, using water as solvent, at moderate temperatures (65 °C) and avoiding the use of phosphine derivatives, Cu(I) as co-catalyst and excess of any of the reactant. Therefore, the reported Pd(II)-HBPEI carbon-supported material can be considered a truly competitive heterogeneous Pd(II) catalyst for large-scale under green chemistry conditions.

Novel positively charged PVDF/SPES membranes surface grafted by hyperbranched polyethyleneimine (HBPEI): Fabrication, characterization, antifouling properties, and performance on the removal of cationic E-coat paint

Surface modification of ultrafiltration membranes has shown a significant potential to reduce fouling and increase flux and lifetime, which are the most important factors in membrane filtration. In this study, the surface-modified membranes were prepared by grafting hyperbranched polyethyleneimine (HBPEI) onto polyvinylidene fluoride (PVDF)-sulfonated polyethersulphone (SPES) blending membranes. Electrostatic interactions between HBPEI and SPES result in a well-attached positive-charged HBPEI grafting layer on the PVDF membrane surface. Surface-modified membranes were examined for the removal of cationic E-coat paint and their performance was measured in terms of total permeation flux, paint rejection, and fouling resistance parameters. In addition, the physicochemical properties and morphology of the membranes were examined by field emission scanning electron microscopy (FESEM), Fourier-transformed infrared spectroscopy (FTIR), atomic force microscopy (AFM), and water contact angle (CA). The optimum membrane shows a total permeation flux of 35.5 L per square meter per hour (LMH) and paint rejection of 99.9%. Additionally, the fouling parameter of the optimized membrane shows a flux recovery ratio of 90%. As a result of its considerable properties, such as the high flux and separation performance as well as its antifouling properties, the surface modified membrane is an excellent candidate for the removal of E-coat paint at industrial scale.