Efficient CO_2 capture on low-cost silica gel modified by polyethyleneimine

In this work, a series of polyethyleneimine （PEI） functionalized commercial silica gel were prepared by wet impregnation method and used as CO2 sorbent. The as-prepared sorbents were characterized by N2 adsorption, FT-1R and SEM techniques. CO2 capture was tested in a fixed bed reactor using a simulated flue gas containing 15.1% CO2 in a temperature range of 25-100 ~C. The effects of sorption temperature and amine content on CO2 uptake of the adsorbents were investigated. The silica gel with a 30 wt% PEI loading manifested the largest CO2 uptake of 93.4 mgcoz/gadsorbent （equal to 311.3 mg^oz/gPEI） among the tested sorbents under the conditions of 15.1% （v/v） CO2 in N2 at 75 ~C and atmospheric pressure. Moreover, it was rather low-cost. In addition, the PEI-impregnated silica gel exhibited stable adsorption-desorption behavior during 5 consecutive test cycles. These results suggest that the PEI-impregnated silica gel is a promising and cost-effective sorbent for CO2 capture from flue gas and other stationary sources with low CO2 concentration.

Enhanced adsorptive removal of Cr(VI)in aqueous solution by polyethyleneimine modified palygorskite

Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA).Characterized results confirmed that the Pal has been successfully modified by PEI.The modification of PEI increased the Cr(VI)adsorption performance of the Pal by the adsorption combined reduction mechanism,and amino groups of the adsorbent play the main role in the enhanced Cr(VI)adsorption.The maximum adsorption capacity was 51.10 mg·g^-1 at pH4.0 and 25°C.The adsorption kinetics of Cr(VI)on the adsorbent conforms to the Langmuir isotherm model.The maximum adsorption occurs at pH3,and then the adsorption capacity of PEI-Pal was decreased with the increase of p H values.The adsorption kinetics of Cr(VI)on PEI-Pal was modeled with pseudo-second-order model.The addition of Cl^-,SO4^2-and PO4^3-reduced the Cr(VI)adsorption by competition with Cr(VI)for the active sites of PEI-Pal.The Cr(VI)saturated PEI-Pal can be regenerated in alkaline solution,and the adsorption capacity can still be maintained at 30.44 mg·g^-1 after 4 cycles.The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI)in aqueous solutions.

A NOVEL METHOD TO PREPARE CROSSLINKED POLYETHYLENEIMINE HOLLOW NANOSPHERES

A novel method to prepare crosslinked polyethyleneimine （CPEI） hollow nanospheres was reported. Uniform silica nanospheres were used as templates, 3-aminopropyl trimethoxysilane （APS） was immobilized on the surface of silica nanospheres as couple agent. Aziridine was initiated ring-opening polymerization with the amino groups in APS to form polyethyleneimine （PEI） shell layer. 1,4-Butanediol diacrylate was utilized to crosslink PEI polymeric shell. The silica nanospheres in core were etched by hydrofluoric acid to obtain hollow CPEI nanospheres. The hollow nanospheres were characterized by X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, and thermogravimetric analysis （TGA）.

SURFACE TREATMENT OF POLY (ETHYLENE TEREPHTHALATE) FABRIC WITH POLYETHYLENEIMINE

A branched polyethyleneimine (BPEI) was applied to poly(ethylene terephthalate)(PET) fabric to improve its surface moisture absorption so that the fabric becomes lessliable to retention of electrostatic charg. The durability of this treatment was assessed bywashing and followed by measurement of charge development on the fabric. The treatedsamples showed improved surface wetting compared to the untreated. The results areconsistent with attachment of the BPEI to the PET surface by a cross-linking mechanism.

SYNTHESIS OF SILICAS-SUPPORTED POLYETHYLENEIMINE AND ITS ADSORPTION PROPERTIES

Abstracts . In this paper, a silicas-supportedpolyethyleneimine resin is synthesized and its adsorption proper-ties are studied. Its selectivity of sorbing heavy metal ion will vary considerably as the pH value of solution varies. In hy-drochloric acid,the resin only sorbs Au(Ⅱ). This suggests that the resin is applicable to the separation of copper (Ⅱ) or gold (Ⅲ).

Ion Exchange Equilibrium between DOWEX 1X8 Resin Modified by Polyethyleneimine and Electrolyte Solutions

In order to improve the selectivity of anion exchange resin, the surface of gel type anion exchange resin was modified with polyethyleneimine (PEI). In the proposed work an attempt to the utilization of commercial anion exchange resin modified by adsorption of polyethyleneimine was investigated. Many conditions of modification of anion exchange resin surface were studied. The influent parameters on the DOWEX 1X8 resin modification were determined using a factorial experimental design. The ion exchange reactions were studied for modified and unmodified resin and electrolyte solutions containing Cl-,NO3-,SO42-. All experiments were performed at constant ionic strength I = 0.3 mol·L-1 and constant temperature T = 298 K. Ionic exchange isotherms were established for the binary systems:Cl-/NO3-,Cl-/SO42- and NO3-/SO42-. The obtained results show that nitrate ion was more sorbed than chloride and sulfate. The order of preference for the anions studied in this investigation is:NO3->Cl->SO42-. All the results given by this resin were compared with those obtained with the AMX anion exchange membrane. Selectivity coefficients and thermodynamic constants for the three binary systems and for the two resins were determined. The modified resin became more selective towards monovalent anions.

Folate-Polyethyleneimine Grafted Polymer Multilayer Hollow Microcapsules as a Slow-Release Carrier of Doxorubicin

A novel biodegradable and biocompatible multilayer hollow microcapsules,modified by folate-conjugated polyethyleneimine(PEI),as targeted and sustained release carriers of doxorubicin(DOX),were successfully synthesized using the sequential layer-by-layer electrostatic assembly technique from the sacrificial microtemplates(CaCOj/CMC,spherical,1.7 μm) with chitosan(CS) and sodium carboxymethyl cellulose(CMC) as the polycation and polyanion polyelectrolyte.Scanning electron microscope(SEM) observation showed that the diameter of the seven assembly multilayer microparticles was about 2.0 μm with relatively regular sphere.After the microparticle cores was removed by complexation with ethylene diamine tetraacetic acid(EDTA) for calcium ions,the range of 200- 300 nm wall thickness of microcapsules was built,and it made the forming microcapsules to be stable.Thermogravimetric analysis confirms the deposition and modification total amount of polymer on the microtemplates is about33.5%.The assembly microparticles were modified by introducing PEI,and the grafting rate of folate could reach 20.0%.It was 4times that of traditional method.The high grafting rate helped to improve targeting action of microcapsules.The deposition of DOX was prominent and the encapsulation efficiency was 96.9%,and the plateaued release of loaded drug reached 78%in pH 7.4 buffer solution,and then in pH 5.7 showed significantly a slow release.

Adsorption of CO₂on Polyethyleneimine 10k—<i>Mesoporous silica</i>Sorbent: XPS and TGA Studies

A CO2 solid sorbent based on polyethyleneimine 10k (PEI-10k) impregnated into mesoporous silica (MPS) foam was synthesized and utilized to capture CO2 at temperatures ranged from 65°C to 95°C. The calculated nitrogen and carbon contents in the bulk of the PEI-10k/MPS sorbent were similar to the XPS results measured on the surface of the foam, suggesting that the PEI was homo-geneously distributed throughout the MPS support. After CO2 adsorptionthe N 1s peak was broadened and could be resolved into two components: a high binding energy component (~401 eV) and a lower binding energy one (396 eV), respectively. The former nitrogen states are consistent with a protonated amine, presumably, due to carbamate formation. The lower binding energy component (~396 eV) could possibly be due to strongly chemisorbed CO2. The maximum sorption capacity was about 4 mmole CO2/g sorbent at 85°C and 1 bar. This capacity was doubled by raising the CO2 pressure to 24.95 bars. The adsorption results can be described by a Langmuir adsorption isotherm.

Effect of Polyethyleneimine Assisting the Growth of Eu-doped ZnO Nanowire Arrays in Mannich Reaction

In study on the growth reaction mechanism of Eu-doped ZnO nanowire（NW）, the intermedium of reaction is characterized by measures such as FTIR. Besides, the influences of polyethyleneimine（PEI） on morphology, structure and photoelectric property of NW are observed by SEM, TEM, XRD, UV-vis and PL spectrum. According to the result, it manifests that Eu-doped ZnO NW array growth response experiences six mutually associated reaction processes in PEI-HMTA system：（a） chelation reaction of PEI and Zn^2＋ ＆ Eu^3＋;（b） protonation reaction of PEI and NH_3;（c） decomposition reaction of hexamethylenetetramine（HMTA）;（d） Mannich reaction of HCHO and PEI;（e） formation of precursor of Eu-doped ZnO;（f） dehydration condensation of Eu-doped ZnO precursors, further forming a doped ZnO NW array. Among them, PEI is the key factor of the whole doping growth reaction process. It both plays a role in modifying the growth of ZnO NW and makes it become longer and thinner. In the meantime, it also facilitates doping of Eu and enables ZnO NW to capture more photoelectrons and higher transmission rate, which is critical to improve photovoltaic performance of optoelectronic devices.

Unconventional Fluorescent and Multi-responsive Polyethyleneimine with LCST and UCST Behavior:Synthesis,Characterization and Biological Applications

Non-aromatic fluorescent and multi-responsive materials,exhibiting inherent fluorescence emission and controlled phase change,have garnered significant attention in recent years.However,the underlying interaction between their fluorescent properties and phase transition remains unclear.In this study,we synthesized a series of catalyst-free aza-Michael addition-based polyethyleneimine(RFPEI)materials by reacting polyethyleneimine(PEI)with N-isopropyl acrylamide(NIPAM).The resulting RFPEI was comprehensively characterized,and demonstrated dual-phase transition behavior(LCST and UCST)in water,which could be finely tuned by adjusting its composition or external factors such as pH.Notably,upon UV irradiation(365 nm),RFPEI exhibited strong fluorescence emission.We further investigated the effects of NIPAM grafting percentage to PEI,polymer concentration,and pH on the LCST/UCST and fluorescent properties of RFPEI aqueous solutions.Moreover,we showcased the great potential of RFPEI as a versatile tool for physiological cell imaging,trace detection,and controlled release of doxorubicin.Our study presents a novel class of stimuli-responsive fluorescent materials with promising applications in the field of biomedicine.

Synergistic enhancement effect of polydopamine-polyethyleneimine hybrid films for a visible-light photoelectrochemical biosensing interface

Photoelectrochemical(PEC)active interfaces exhibiting visible-light responses and good electron-transfer ca-pabilities are key to the development of PEC biosensors.In this study,bioinspired polydopamine(PDA)-polyethyleneimine(PEI)hybrid films were designed to engineer inorganic semiconductors and construct PEC biosensing interfaces.The charge-transfer capability and visible-light-response property of PDA were combined with the electron-attracting ability of PEI to produce a synergistic PEC-enhancement effect.The achieved PEC-enhancement effect was versatile for photoanode and photocathode semiconductors.Further,the role of PEI doping was revealed via electrochemical investigations.Compared with the PDA sensing platform,the hybrid sensing interface offered by the PDA-PEI film exhibited enhanced analytical performances toward ascorbic acid(AA),achieving a larger detection range and a lower limit of detection.

Novel polyethyleneimine/TMC-based nanofiltration membrane prepared on a polydopamine coated substrate

Most commercial NF membranes are negatively charged at the pH range of a typical feed solution. In order to enhance the removal of cations （such as Mg2＋ or Ca2＋）, we utilized polyethyleneimine （PEI） and trimesoyl chloride （TMC） to perform interfacial polymerization reaction on a polydopamine coated hydrolyzed polyacry-lonitrile substrate to obtain a positively charged nanofiltration membrane. Effects ofpolydopamine coating time, PEI concentration, TMC reaction time and concentration on the membrane physicochemical properties and separation performance were systematically investigated using scanning electron microscopy, streaming potential and water contact angle measurements. The optimal NF membrane showed high rejection for divalent ions （93.6±2.6% for MgSO4, 92.4±1.3% for MgCl2, and 90.4±2.1% for Na2SO4）, accompanied with NaCl rejection of 27.8±2.5% with a permeation flux of 17.2±2.8 L.m-2.h-1 at an applied pressure of 8 bar （salt concentrations were all 1000 mg.L-1）. The synthesized membranes showed promising potentials for the applications of water soft-ening.

Folic Acid Modified Electrospun Poly(vinyl alcohol)/Polyethyleneimine Nanofibers for Cancer Cell Capture Applications

Capture and detection of metastatic cancer cells are crucial for diagnosis and treatment of malignant neoplasm. Here, we report the use of folic acid （FA） modified electrospun poly（vinyl alcohol） （PVA）/polyethyleneimine （PEI） nanofibers for cancer cell capture applications. Electrospun PVA/PEI nanofibers crosslinked by glutaraldehyde vapor were modified with FA via a poly（ethylene glycol） （PEG） spacer, followed by acetylation of the fiber surface PEI amines. The formed FA-modified nanofibers were well characterized. The morphology of the electrospun PVA/PEI nanofibers is smooth and uniform despite the surface modification. In addition, the FA-modified nanofibers display good hemocompatibility as confirmed by hemolysis assay. Importantly, the developed FA-modified nanofibers are able to specifically capture cancer cells overexpressing FA receptors, which were validated by quantitative cell counting assay and qualitative confocal microscopy analysis. The developed FA-modified PVA/PEI nanofibers may be used for capturing circulating tumor cells for cancer diagnosis applications.

Control of Aggregate Size of Polyethyleneimine-Coated Magnetic Nanoparticles for Magnetofection

Using magnetic nanoparticles to enhance gene transfection,a recently developed technique termed magnetofection,has been shown to be a powerful technology in gene delivery.The most widely used magnetic nanoparticles in this area are those coated with polyethyleneimine,which is a well known non-viral transfection agent.In this article,we report methods to control the aggregate size of polyethyleneimine-coated magnetite particles.These particles were then used to enhance transfection of green fluorescent protein(GFP)into NIH 3T3 cells in vitro.We find that the aggregate size of the particles has a great effect on their performance in magnetofection,with less aggregated magnetic particles being more effective in enhancing the gene transfection.

Polyethyleneimine-modified calcium carbonate nanoparticles for p53 gene delivery

In this study,calcium carbonate(CaCO3)nanoparticles with spherical structure were regulated by arginine and successfully synthesized via a facile co-precipitation method.The average particle size of as-prepared CaCO3 was about 900 nm.The properties of nanostructured CaCO3 particles were characterized by scanning electron microscope,Fourier transform infrared spectroscopy,Xray diffraction and size distribution.After modified with polyethyleneimine(PEI),the ability of PEICaCO3 nanoparticles to carry GFP-marked p53 gene(pEGFP-C1-p53)into cancer cells to express P53 protein were studied.Meanwhile,the cytotoxicity,transfection efficiency,cells growth inhibition and the ability to induce apoptosis by expressed P53 protein were conducted to evaluate the performances of PEI-CaCO3 nanoparticles.The results show that prepared PEI-CaCO3 nanoparticles had good biocompatibility and low cytotoxicity in a certain concentration range.PEI-CaCO3 effectively transfected pEGFP-C1 gene into epithelial-like cancer cells.And with the expression of GFP-P53 fusion protein,pEGFP-C1-p53-gene-loaded PEI-CaCO3 particles significantly reduced the proliferation of cancer cells.These findings indicate that our PEI-modified CaCO3 nanoparticles are potential to be successfully used as carriers for gene therapy.

Characterization of synergistic anti-tumor effects of doxorubicin and p53 via graphene oxide-polyethyleneimine nanocarriers

Co-delivery of chemical drugs and therapeutic genes for synergistic therapy provides a promising strategy to treat devastating diseases. However, the real-time coordination patterns between chemical drugs and therapeutic genes remain poorly understood. Herein, the complexes of doxorubicin/graphene oxidepolyethyleneimine/p53 plasmid（Dox/GO-PEI/p53） were fabricated and employed to investigate the synergistic manner between Dox and p53 in the inhibition of He La cell growth. GO was conjugated with PEI to form the GO-PEI backbone as the delivery vector. The GO backbone provided surfaces with a high specific area to load Dox via the π-π stacking interaction, and was able to release Dox significantly faster at pH 5.0 than at pH 7.0, while the positively charged PEI section of GO-PEI could condense plasmids into GO-PEI/DNA nanoparticles via the electrostatic interaction. The nanoparticles efficiently mediated the transfection of DNA in He La cells, with lower cytotoxicity compared to PEI/DNA nanoparticles. Furthermore, the complexes of Dox/GO-PEI/p53 released Dox and expressed p53 gene in a sequential manner,and showed successive inhibition of the in vitro growth of He La cells. This type of drug/GO-PEI/DNA complex can be employed as a platform to investigate the coordination pattern between chemical drugs and therapeutic genes for tumor therapy.

Comparison Study of Corrosion Behavior and Biocompatibility of Polyethyleneimine (PEI)/Heparin and Chitosan/Heparin Coatings on NiTi alloy

Biomedical molecule has received extensive application in surface modification coating.In this paper,polyethyleneimine （PEI）/heparin coating and chitosan/heparin coating on NiTi alloy substrates were prepared by layer-by-layer method,and differences of corrosion behavior and biocompatibility of the coatings were studied.Static contact angles and Fourier transform infrared （FT-IR） test were used to analysis the surface morphology and structure character of the materials,and atomic absorption spectrum was used to verify the corrosion behavior of the materials.Furthermore,hemolysis,dynamic clotting time and platelet binding test were utilized to investigate the biocompatibility of the materials.The results revealed that the blood compatibility of PEI/heparin coating is better than that of the chitosan/heparin coating as well as the substrate.

Guanidinoamidized Linear Polyethyleneimine for Gene Delivery

Guanidine was introduced to low molecular weight linear polyethyleneimine （LPEI） via amide groups, to explore the effect of both guanidine degree and pendant chain length on its transfection behavior. The resulting guanidinoamidized LPEIs （GLPEIs） could dramatically reduce LPEI＇s toxicity, enhance its DNA-packaging capability, cellular uptake and therefore transfection efficiency. These polyplexes were taken up very efficiently via caveolae-mediated endocytosis and their transfection efficiencies in ovarian cancer cells were significantly improved compared to native LPEIlok polyplexes. Among these GLPEIs, LPEI-C3-G100 showed higher DNA affinity even than LPEI25k and the highest transfection efficiency, probably due to the optimization of polymer chain flexibility. Of notice, LPEI-C3-G100 polyplexes could more effectively accumulate into cytoplasm than LPEI25k, although the transfection efficiency of LPEI-C3-G100 polyplexes was not superior to that of LPEI25k polyplexes, which would be probably attributed to the more efficient release of LPEI25k polyplexes than LPEI-C3-G100 polyplexes in the cytoplasm.

Electrodeposition of Copper from Citrate Alkaline Solution Containing Polyethyleneimine(PEI)

Mechanism of citrate alkaline copper electrodeposition in presence of polyethyleneimine was researched.Tested by SEM,It's propitious to obtain fine and symmetrical copper film at wider current densities with polyethyleneimine.XRD analysis indicated copper deposits exhibited growth orientation of crystal face(111),which remained with parallel growth.Cyclic voltammograms results indicated that polyethyleneimine adsorbing preferentially at cathode high current density area could make a stronger inhibition on copper electrodeposit.Studied by chronoamperometry,it's showed that initial stage behavior of copper electrodeposition belonged to diffusion controlled and three-dimensional progressive nucleation.

Self-assembled graphene oxide/polyethyleneimine films as high-performance quartz crystal microbalance humidity sensors

As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this study,a facile chemical layer-by-layer self-assembly(CLS)method was developed for fabricating graphene oxide(GO)/polyethyleneimine(PEI)multilayer films.Owing to the chemical bonding between the PEI and GO,and the intrinsic stickiness of the PEI,layered films with different numbers of layers were successfully prepared using the CLS method and confirmed through ultraviolet-visible(UV-Vis)spectroscopy and the mass loading of quartz crystal microbalance(QCM).Morphological measurements revealed that the roughness and thickness of the films increased exponentially with the number of bilayers.The GO/PEI films were deposited on QCM electrodes using the CLS method to produce the humidity sensors.The humidity measurement results showed a high sensitivity(37.84 Hz/%RH)and rapid response/recovery(<5 s/8 s)of the optimal sensor,which was superior to that of recently developed QCM sensors.