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1.
Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprolactone (ε-CL) with tin (Ⅱ) 2-ethylhexanoate as catalyst and n-butyl alcohol as initiator.Secondly,the PCL reacted with isophorone diisocyanate (IPDI) to prepare PCL with isocyanate functional group (PCL-NCO).Hydroxylamine was used to degrade gelatin by the cleavage between asparagine and glycine residues of gelatin.PCL-NCO reacted with the hydroxyl/amino groups of degraded gelatin in a homogeneous system and yielded the PCL modified gelatin copolymers.The gelatin grafted PCL copolymers were measured by means of XRD,FTIR,DSC and 1 H NMR.The results confirmed the conjugation of PCL onto gelatin chains.The PCL modified gelatin can be used as biomaterials owing to their biocompatibility and biodegradation.  相似文献   

2.
Pepsin was assembled on the surface of prepared poly (ethylene terephthalate) (PET-NH3 +) substrates. The composition and structure of the pepsin/PET-NH3 + assembling films in different condition were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).  相似文献   

3.
The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification such as Soxhlet extraction, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry (TG), differential scanning calorimetry (DSC) and zeta potential (ζ). The results of FT-IR and TG-DSC show that the desired reaction chains have been covalently bonded on the surface of ZnO nanoparticles. Zetasizer results reveal that themaximal absolute value of ζ of the modified ZnO particles in acetone medium was 67.0 mV, which was much higher than that of the unmodified ZnO particles. So the surface of nanosized ZnO changed from hydrophilicity to hydrophobicity and the dispersity of ZnO nanoparticles were improved simultaneously. Finally, the mechanism of graft modification was discussed.  相似文献   

4.
Positively charged composite nanofiltration (NF) membranes with good stability were prepared by dopamine (DA) assisted poly(ethylene imine) (PEI) deposition on a polysulfone ultrafiltration (UF) substrate followed by a cross-linking step. Attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electronic microscopy, and atom force microscopy were employed to characterize the surface chemistry and morphology of the obtained composite membranes. The DA and PEI co-deposition conditions were optimized based on knowledge of the co-deposition mechanism. The effects of the cross-linker concentration, cross-linking time, and reaction temperature on the permeation and separation properties of the prepared composite membranes were investigated in detail. Under optimized conditions, the MgCl2 rejection and permeation flux of the composite membrane reached 80.4% and 19.6 L/(m2·h), respectively (the feed was 0.01 mol/L of MgCl2 solution under a test pressure of 0.4 MPa). The rejection of various salts followed the order MgCl2≈CaCl2>MgSO4>NaCl>Na2SO4, suggesting the membranes were positively charged. The composite membranes showed good durability under alkaline aqueous conditions. This study provided new insights into the fabrication of mussel-inspired thin-film composite nanofiltration membranes.  相似文献   

5.
Modification of poly(tetrafluoroethylene) (PTFE) films with 2-methacryloyloxyethyl phosphorylcholine (MPC) was performed by low-temperature plasma treatment and grafting polymerization. Surface properties of PTFE were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra, X-ray photoelectron spectroscopy (XPS), and static contact angle. The results show that MPC has been grafted onto PTFE film surface successfully. Contact angle for the modified PTFE films in the water decreased from 108° to 58.25°, while surface energy increased from 17.52 mN/m to 45.47 mN/m. The effects of plasma treatment time, monomer concentration and grafting time on degree of grafting were determined. In the meanwhile, blood compatibility of the PTFE films was studied by checking thrombogenic time of blood plasma.  相似文献   

6.
Elemental mercury capture on heat-treated activated carbon (TAC) was studied using a laboratory-scale fixed bed reactor. The capability of TAC to perform Hg0 capture under both N2 and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components. The results suggest that surface functional groups (SFGs) on activated carbon (AC) are vital to Hg0 capture in the absence of acid gases. Meanwhile, the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg0 capture. The presence of HCl, NO2, and NO individually in basic gases markedly enhances Hg0 capture on TAC due to the heterogeneous oxidation of Hg0 on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC. Similarly, the presence of SO2 improves Hg0 capture by about 20%. This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO2 due to catalysis on the carbon surface. Furthermore, O2 exhibits a synergistic effect on Hg0 oxidation and capture when acid gases are present in the flue gases.  相似文献   

7.
Black clay(BC) was used as a catalyst for the decolorization of Azure B dye by Fenton process. BC was modified by acid, alkali, distilled water, and calcination to check their changes in characterization and efficiency on decolorization of Azure B. Among three modified catalysts, maximum decolorization was obtained by acid-modified BC(AMBC) catalyst due to the highest removal of impurities, comparatively. The characterization of AMBC was done by Fourier-transform infrared spectroscopy and X-ray diffraction spectroscopy which show the presence of metal ion. The BET surface area, pore volume, pore size, and density of AMBC were calculated to be 79.402 m~2/g, 0.0608 m~3/g, 0.00306 nm, and 16 g/cm~3, respectively. The highest decolorization of 97.59% was achieved only in 10 min using AMBC at optimized calcination of 100 °C and 3 h of aging. AMBC was considered as the main catalyst for optimizing the different process parameters. Optimized conditions were obtained: pH 2, 0.2 mL of H_2O_2, catalyst dose 0.3 g, room temperature(30 °C), and stirring speed 400 r/min. The catalyst has showed excellent stability and reusability. It could remove more than 85% of color even after four cycles of run and less than negligible leaching of iron. AMBC has good recycling ability among other modified catalysts. To check the selectivity of catalyst, different dyes such as Congo red and mixed dye(mixture of Azure B and Congo red) decolorization were studied. In the present work, kinetic study was also carried out and a three-stage decolorization process was found.  相似文献   

8.
采用氨解结合乳化及热致相分离的技术来制备改性聚乳酸微球,通过浸泡法让卵磷脂包裹在改性微球上,进一步提高改性微球的亲水性。探讨了卵磷脂溶液的浓度、浸泡时间对改性微球形貌和亲水性能的影响。实验结果表明,卵磷脂修饰改性微球的最佳制备工艺条件为:卵磷脂溶液的浓度为1%,浸泡时间为5h,在此条件下制备的微球卵磷脂包裹均匀且亲水性得到了改善。通过红外光谱,X射线光电子能谱表征微球,结果表明卵磷脂已经成功接枝到改性微球上,通过水接触角测试,卵磷脂修饰后的改性微球亲水性得到了进一步提高。  相似文献   

9.
The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.  相似文献   

10.
研究目的：腐殖酸（HA）对富勒烯（C60）粉末的悬浮作用以及pH、离子强度对HA-C60悬浮性能的影响。创新要点：研究水质条件对C60悬浮性能的影响。研究方法：测定C60粉末在HA溶液中的zeta电位,水力学粒径和悬浮浓度;HA存在下,C60悬浮体系的zeta电位与水力学粒径随pH的变化及C60悬浮体系团聚动力学随离子强度的变化。重要结论：HA对C60粉末起到一定的分散作用,但不能使其长时间稳定悬浮于水中。当pH〈4时,C60水悬液开始沉淀;而当HA存在时,C60水悬液在pH 3-11范围内都保持稳定,这是由于HA吸附于C60表面,通过静电排斥和空间位阻作用,促进C60分散悬浮。C60水悬液的稳定性随盐离子价位和浓度升高而降低。HA会抑制Na＋对C60水悬液的脱稳作用;但高价离子Ca2＋和La3＋存在时,HA与C60之间会发生桥联从而促进C60水悬液脱稳沉淀。  相似文献   

11.
Liu  Yongling  Wu  Songhai  Jia  Shaoyi  Liang  Zongsheng  Han  Xu 《天津大学学报(英文版)》2019,25(4):371-380
Natural pyrites contain high levels of adsorbed and structurally incorporated arsenic(As),which may simultaneously result in the release of As and affect the oxidation process of pyrite.However,the oxidation and electrochemical behaviors of As on the oxidation reactivity of pyrites are still not clear.In this study,pyrite was prepared by a hydrothermal method and applied to study the oxidation mechanism between pyrite and aqueous arsenate.Analyses of X-ray diffraction,X-ray photoelectron spectroscopy,and scanning electron microscopy demonstrate that the as-prepared sample is an octahedron-like pyrite with high purity and crystallinity.The interaction between As(V)and pyrite as well as the electrochemical behaviors of pyrite oxidation in the presence of aqueous arsenate were investigated under acidic conditions by an ion analysis method,cyclic voltammetry(CV),Tafel,and electrochemical impedance spectroscopy(EIS).The results of the chemical reaction indicate that electrons are transferred from S _2~(2-)to dissolved oxygen with the formation of SO _4~(2-)in the initial As(V)concentration range of 0–0.3 mmol/L.In the initial As(V)concentration range of 0.4–1.2 mmol/L,electrons are transferred from S _2~(2-)to As(V)with the formation of elemental S ~(0 )and As(III).The CV,the Tafel plot and EIS analyses indicate that aqueous arsenate in an electrolyte promotes oxidation reactivity and passivation of the pyrite electrode.Moreover,the electron transfer rate increases with increasing aqueous arsenate concentration in the electrolyte.  相似文献   

12.
In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were obtained from a combination of experimental observation and hypothetical models. The results clearly showed that both the oxidation rate of toluene and generation rate of the aromatic product were proportional to the concentration of the substrate, the partial pressure of oxygen and the surface area of the catalyst. The energy barrier of toluene oxidation to benzyl alcohol was the highest(≈ 81 kJ mol~(-1)), while that of benzyl alcohol oxidation to benzaldehyde was the lowest(≈ 57 kJ mol~(-1)). Moreover, the activation energy of further oxidation of benzaldehyde in an acetic acid solvent was only slightly lower(≈ 1.9 kJ mol~(-1)) than that of toluene oxidation. Significantly, the transformation of benzyl alcohol indeed contributed to the generation of benzaldehyde and this step conformed to a first-order parallel-consecutive model. Increased reaction temperature and residence time favored the transformation of benzyl alcohol to benzaldehyde. In addition, doping with molybdenum at Mn/Mo = 3/1 enhanced the catalytic performance of the heterogeneous catalyst and was attributed to the presence of a synergetic effect between different metal cations. Regarding the microscopic kinetics, the LH-OS-ND mechanism(Langmuir–Hinshelwood adsorption of reagents on the same type of active sites and non-dissociative adsorption of oxygen) was verified as responsible for the heterogeneous oxidation of toluene. Oxygen and benzaldehyde were weakly adsorbed(Δ H_(ads,Oxy) ≈~(-1)5 kJ mol~(-1), Δ H _(ads)0,Bald) ≈-30 kJ mol~(-1)), but showed strong mobility(Δ S_(ads,Oxy) ≈-22 J mol~(-1) K~(-1)), Δ S_(ads,Bald) ≈-39 J mol~(-1) K~(-1)). The fundamental intrinsic rates were deduced based on the LH-OS-ND mechanism and showed great consistency with the macroscopic results.  相似文献   

13.

The metal oxide/nitrogen-doped carbon (NC) compounds zirconium oxide/NC (ZrO2/NC) and cerium oxide/NC (CeO2/NC) were synthesized via the pyrolysis of polyaniline on the metal oxide surface. The characterization of the ZrO2/NC and CeO2/NC catalysts showed more active CO2 reduction reaction activity than that of NC catalyst without metal oxide. Gas chromatography analysis revealed that CO and H2 were the primary products, and no liquid-phase products were detected via proton nuclear magnetic resonance spectroscopy or high-performance liquid chromatography. The maximum Faraday efficiency of ZrO2/NC reached 90% at − 0.73 V (vs. RHE), with the current density of CO at 5.5 mA/cm2; this Faraday efficiency value was higher than that of NC (41%), with the current density of CO at 3.1 mA/cm2. The interaction between the metal oxide and carbon allowed the efficient formation of defect sites, especially imine-type nitrogen, strengthening the adsorption of the key reaction intermediate CO2•− and thus promoting the CO2 reduction reaction.

  相似文献   

14.
The simultaneous sorption behavior and characteristics of cadmium (Cd) and sulfamethoxazole (SMX) on rice straw biochar were investigated. Isotherms of Cd and SMX were well modeled by the Langmuir equation (R2 >0.95). The calculated maximum adsorption parameter (Q) of Cd was similar in single and binary systems (34129.69 and 35919.54 mg/kg, respectively). However, the Q of SMX in a binary system (9182.74 mg/kg) was much higher than that in a single system (1827.82 mg/kg). The presence of Cd significantly promoted the sorption of SMX on rice straw biochar. When the pH ranged from 3 to 7.5, the sorption of Cd had the characteristics of a parabola pattern with maximum adsorption at pH 5, while the adsorption quantity of SMX decreased with increasing pH, with maximum adsorption at pH 3. The amount of SMX adsorbed on biochar was positively correlated with the surface area of the biochar, and the maximum adsorption occurred with d 250 biochar (biochar with a diameter of 150-250 μm). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed that the removal of Cd and SMX by rice straw biochar may be attributed to precipitation and the formation of surface complexes between Cd or SMX and carboxyl or hydroxyl groups. The results of this study indicate that rice straw biochar has the potential for simultaneous removal of Cd and SMX from co-contaminated water.  相似文献   

15.
提出一种基于酶催化沉积底物和生物素——亲和素两步放大的超灵敏免疫检测方法.抗体通过单层蛋白A固定到金电极表面,预先处理好的生物素化抗体和辣根过氧化物酶（HRP）标记的亲和素形成的网状复合物作为免疫反应信号的放大探针.在有H2O2存在的情况下,通过辣根过氧化物酶（HRP）催化氧化DAB（3,3’—联苯二胺）在金电极上沉积一层不溶物,引起阻抗的显著增大.该传感器用于人IgG检测,检测下限为1.0×10^-8g.采用法拉第阻抗和压电石英晶体微天平分别表征了该传感器的特性.  相似文献   

16.
A series of ferrocene- and azobenzene-based compounds with acyl amine groups attached were designed and synthesized to explore their potential application in anion recognition. Their electro- and photo-properties, and the effect of nitro and amine substituents of the benzene ring on anion recognition were studied by UV-vis absorption spectroscopy (UV) and cyclic voltammetry (CV). The results showed that a nitro group substituent has a positive effect on the binding affinity and sensitivity, which might be due to the strong hydrogen bonding interaction between the receptor and the guest, while an amino group substituent has a negative effect on the sensitivity. Furthermore, the shift in the UV-vis absorption spectra was observed as a color change, which can be used for the naked-eye detection of F? and H2PO 4 ? .  相似文献   

17.
The copolymerization of CO and styrene catalyzed by Pd/C toward the formation of polyketones(PK)was studied in the N-valeronitrile-N'-methylimidazolium hexafluorophosphate([C4CNmim]+PF-6) medium. The synthesized PK was characterized by Fourier transform infrared(FTIR), elemental analysis, 13C-nuclear magnetic resonance(13C-NMR), differential scanning calorimetry(DSC), thermogravimetric analysis(TGA) and gel permeation chromatography(GPC). The supported ionic liquid film on the surface of Pd/C catalyst can prevent the products from covering the hole of active carbon due to its chemical stability and weak coordination ability with metal ions, and thus efficiently improve the catalytic activity. The effects of different amounts of ionic liquid on the catalytic activity and reusability of the catalyst and the molecular weight of PK were discussed. When the usage of ionic liquid is 10wt%(0.1 g ionic liquid / 1 g active carbon carrier) and the theoretical content of Pd2+ is 5wt%(0.05 g Pd2+/ 1 g active carbon carrier), the highest catalytic activity 2 963.64 gSTCO/(gPd·h) is achieved with the molecular weight and polydispersity index of PK as Mn=9 684, Mw=13 452 and Mw /Mn=1.389.  相似文献   

18.
This new type nanocomposite powder was prepared with electroless plating enhanced by ultrasonic wave. High-resolution transmission electron microscopy (HRTEM) showed that As-plated particles have nanometer scale average size. X-ray diffraction (XRD) analysis showed the presence of a noncrystalline structure in the plating layer on the nano-Al2O3 matrix. The content of the plating layer was analyzed by energy dispersive X-ray spectroscopy (EDX) technology. The plating layer content was adjustable by changing the solution concentration.  相似文献   

19.
In this paper, the obtained experimental results concerning creation of bulk elementary excitations (BEEs) in iso-topically pure liquid 4He at low temperatures ~60 mK are discussed. Positive rotons’ (R -rotons) creation by a pulsed heater was studied. Signals were recorded for the following quantum processes: quantum evaporation of 4He-atoms from the free liq- uid-helium surface by the BEEs of the liquid helium-II, and BEEs reflection from the free surface back into the bulk liquid. Typical signals are shown, and ratios of signal amplitudes are evaluated. For long heater pulses from 5 to 10 μs, appearance of the second atomic cloud consisting of evaporated 4He-atoms was observed in addition to the first atomic cloud. It is thought that the first atomic cloud of the evaporated helium atoms consists of very fast 4He-atoms with energies ~35 K evaporated by positive rotons with the special energies ~17 K (~2ER~2×8.6 K with ER representing the roton minimum energy) corresponding to the third non-dispersive Zakharenko wave. The second cloud of slower 4He-atoms was created by surface elementary excitations (SEEs or ripplons) possessing the special energies ~7.15 K representing the binding energy. It was assumed that such SEEs can be created by phonons incoming to the liquid surface with special energies ~6.2 K corresponding to the first non-dispersive Zakharenko wave, which can interact at the liquid surface with the same phonons already reflected from the surface for long heater pulses. Also, some pulsed-heater characteristics were studied in order to better understand the features of such heaters in low temperature experi- ments.  相似文献   

20.
Tea (Camellia sinensis L.) seed shells, the main byproduct of the manufacture of tea seed oil, were used as precursors for the preparation of tea activated carbon (TAC) in the present study. A high yield (44.1%) of TAC was obtained from tea seed shells via a one-step chemical method using ZnCl2 as an agent. The Brunauer-Emmett-Teller (BET) surface area and the total pore volumes of the obtained TAC were found to be 1 530.67 mg2/g and 0.782 6 cm3/g, respectively. The equilibrium adsorption results were complied with Langmuir isotherm model and its maximum monolayer adsorption capacity was 324.7 mg/g for methylene blue. Adsorption kinetics studies indicated that the pseudo-second-order model yielded the best fit for the kinetic data. An intraparticle diffusion model suggested that the intraparticle diffusion was not the only rate-controlling step. Thermodynamics studies revealed the spontaneous and exothermic nature of the sorption process. These results indicate that tea seed shells could be utilized as a renewable resource to develop activated carbon which is a potential adsorbent for methylene blue.  相似文献   

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