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Parnuwat Usapein Anchaleeporn W. Lothongkum Prakorn Ramakul Ura Pancharoen 《Korean Journal of Chemical Engineering》2009,26(3):791-798
The selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process by hydrophobic
hollow fiber supported liquid membrane (HFSLM) was investigated. The effects of various parameters— types of organic extractants,
i.e., metyl trioctylammonium chloride (Aliquat 336), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP) and the mixture of
Aliquat 336 and TBP, concentration of the selected extractant, types of stripping solutions (NaCl and NaOH), pH and concentration
of the selected stripping solution, and the operating temperature—were studied. The feed and stripping solutions flowed countercurrently.
The results showed that the coexisting contamination in spent pickling solution of Fe(II) and Ni(II) ions had no significant
effect on Cr(VI) extraction. Among the extractants used in this study, Aliquat 336 was a specific carrier to attain the highest
percentage of Cr(VI) extraction. About 70% extraction was achieved by using 0.11 M Aliquat 336 and 0.5 M NaCl at pH 7. The
percentage of stripping slightly increased when the concentration of NaCl increased. In addition, it was found that the operating
temperature of 20, 30, 40, and 50 °C had almost no influence on the percentages of extraction and stripping of Cr(VI). The
calculated diffusion energy of Cr(VI) extraction was 15.14 kJ/mol. 相似文献
3.
《Ceramics International》2022,48(16):23460-23467
The defected double perovskites, being non-toxic, stable, and capable to exhibit both spin-up (↑) and spin-down (↓) polarizations, are attractive for spintronic devices. In the present article, the role of 5d-electrons of Os and Ir to control the magnetic characteristics of Rb2(Os/Ir)Cl/Br6 is addressed. The structural and magnetic characteristics are investigated using PBEsol-mBJ functional, while thermoelectric behaviors are studied using BoltzTrap code. The computed tolerance factors (0.95/0.98, 0.94/0.96) and formation energies (?2.0/-1.65eV, ?1.70/-1.10eV) confirm the structural and thermodynamic stabilities, respectively. The examination of band structures and density of states have revealed half-metallic ferromagnetic nature, which is further discussed in terms of double exchange model, exchange constants and exchange energies. The presented calculations indicate that underlying hybridization process, exchange energy, and crystal field energy induce ferromagnetism due to electron spin. Furthermore, thermal, and electrical conductivities, power factor, and Seebeck coefficients are computed and discussed to understand the thermoelectric applications. 相似文献
4.
The electrochemical and thermal behaviors of the spinels-LiMn2O4, LiCo1/6Mn11/6O4, LiFe1/6Mn11/6O4, and LiNi1/6Mn11/6O4 were studied using electrochemical and thermochemical techniques. The electrochemical techniques included cyclic voltammetry, charge-discharge cycling of 2016 coin cells and diffusion coefficient measurements using Galvanostatic Intermittent Titration Technique. Better capacity retention was observed for the substituted spinels (0.11% loss per cycle for LiCo1/6Mn11/6O4; 0.3% loss per cycle for LiFe1/6Mn11/6O4; and 0.2% loss per cycle for LiNi1/6Mn11/6O4) than for the lithium manganese dioxide spinel (1.6% loss per cycle for first ten cycles, 0.9% loss per cycle for 33 cycles) during 33 cycles. The Differential Scanning Calorimetry results showed that the cobalt substituted spinel has better thermal stability than the lithium manganese oxide and other substituted spinels. 相似文献
5.
《Journal of the European Ceramic Society》2022,42(3):1061-1076
Yttrium mono- and di-silicates are excellent candidate materials for Environmental Barrier Coatings (EBC), to protect Ceramic-Matrix Composites (CMC). A large distribution of microstructures can be generated by varying the duration of sintering, the particle size distribution of the precursor and/or the deposition method. In the present work, investigations of the corrosion resistance of yttrium silicate coatings with various microstructures in the high temperature range, under different oxidizing environments are reported. An original experimental methodology has allowed quantifying the influence of the microstructure (especially grain size and grain boundary surface area) on properties such as ionic conductivity, resistance to oxygen diffusion, volatilization rate and surface recession, and showing that they directly affect their protection efficiency against oxidation. Based on these results, guidelines for the design of an optimized yttrium silicate EBC featuring microstructural and compositional variations are proposed. 相似文献
6.
Dynamic adsorption behaviors between Cr(VI) ion and water‐insoluble amphoteric starches was investigated. It was found that the HCrO ion predominates over the initial pH ∼ 2–4, the CrO ion predominates over the initial pH ∼ 10–12, and both ions coexist over the initial pH ∼ 6–8. The sorption process occurs in two stages: the external mass transport process occurs in the early stage and the intraparticle diffusion process occurs in the long‐term stage. The diffusion coefficient of the early stage (D1) is larger than that of the long‐term stage (D2) for the initial pH 4 and pH 10. The diffusion rate of HCrO ion is faster than that of CrO ion for both processes. The D1 and D2 values are ∼ 1.38 × 10−7–10.1 × 10−7 and ∼ 0.41 × 10−7–1.60 × 10−7 cm2 s−1, respectively. The ion diffusion rate in both processes is concentration dependent and decreases with increasing initial concentration. The diffusion rate of HCrO ion is more concentration dependent than that of CrO ion for the external mass transport process. In the intraparticle diffusion process, the concentration dependence of the diffusion rate of HCrO and CrO ions is about the same. The external mass transport and intraparticle diffusion processes are endothermic and exothermic, respectively, for the initial pH 4 and pH 10. The kd values of the external mass transport and intraparticle diffusion processes are ∼ 15.20–30.45 and ∼ −3.53 to −12.67 kJ mol−1, respectively. The diffusion rate of HCrO ion is more temperature dependent than that of CrO ion for both processes. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2409–2418, 1999 相似文献
7.
The diffusion process of intercalary species within insertion-host materials is the key step during the whole electrode reaction. Here a novel method based on the ratio (q) of the potentio-charge capacity to the galvano-charge capacity (RPG) was developed to determine the diffusion coefficient of intercalary species for porous electrode by the spherical diffusion model. By the RPG method, the Li+ diffusion coefficients within graphite were determined from the galvano-potentio-charge curves. The values of diffusion coefficient measured at different galvano-charge current or at different cutoff voltage suggested that the RPG method has a good reliability for determination of the diffusion coefficient. 相似文献
8.
C. Montella 《Electrochimica acta》2006,51(13):2778-2781
The article by Tang et al., which was published recently [Electrochim. Acta, Electrochim. Acta 50 (2005) 5581-5587], proposed a novel technique for the determination of diffusion coefficients of intercalated species in host materials. The capacity intermittent titration technique (CITT) is an extension of the ratio of potentiostatic-to-galvanostatic charge (RPG) technique developed initially by the same authors. By the CITT, the Li+ solid-state diffusion coefficient within LiMn2O4 was determined by these authors at different voltages and different galvanostatic-charge currents. In these comments, the ratio of potentiostatic-to-galvanostatic charge is reexamined by taking finite charge-transfer kinetics at the interface and Ohmic drop into consideration. The measurement error of diffusion coefficients evaluated by CITT while using the approximation of infinitely fast charge-transfer kinetics is predicted quantitatively. 相似文献
9.
Rajiv C. Dunne Suresh K. Sitaraman Shijian Luo C. P. Wong William E. Estes Mookkan Periyasamy 《应用聚合物科学杂志》2002,84(4):691-700
The cure kinetics of a photodielectric dry film (PDDF) material called ViaLux 81 has been studied, with the aim of understanding and optimizing its curing schedule for the fabrication of sequentially built‐up (SBU) high‐density‐interconnect printed wiring boards (HDI‐PWB). Initial dynamic differential scanning calorimetry (DSC) scans on the material revealed a two‐stage curing mechanism due to the long lifetime of the photoinitiator catalyst, which could not be separated at lower heating rates. On the other hand, the heat flow exotherm from isothermal DSC experiments showed a rapid reaction rate at the beginning with only a single peak. Therefore, to capture the complexity of the process, the faster multiple heating rate DSC experiments are used to predict the degree‐of‐cure (DOC) evolution. Two approaches have been developed based on the dynamic DSC data: (1) a “model‐free” approach, which only requires information about the cure‐dependence of the activation energy; and (2) a practical scheme to deconvolute the two curing peaks. Excellent agreement is observed for the heating rate experiments, but the methods are inadequate for predicting the DOC evolution under isothermal conditions. Therefore, a modified autocatalytic model with temperature‐dependent kinetic parameters has been developed based on the isothermal DSC data. This model predicts the DOC evolution for isothermal curing profiles very well. However, some discrepancy is evident in predicting the DOC evolution for heating rate experiments, due to the underestimation of the activation energy. With appropriate corrections, excellent predictive capability is illustrated for complex cure schedules with combined heating rate and isothermal segments. In addition, a cure process optimization strategy has been suggested, and the fabrication of fine features and microvias is demonstrated. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 691–700, 2002; DOI 10.1002/app.2345 相似文献
10.
Integration of immersed membrane ultrafiltration with the reuse of PAC and alum sludge (RPAS) process for drinking water treatment 总被引:2,自引:0,他引:2
Effects of PAC and alum sludge generated from water treatment process on the effluent quality and fouling of immersed UF membrane were systematically investigated with representative source of natural water and the efficiency of coagulation, PAC adsorption and RPAS to treat natural surface water prior to UF were compared. It was found that the average turbidity removal by RPAS could reach up to 80.2%, and the turbidity removal of immersed membrane UF was independent of the influent, which could be kept at 99%. Particulates were reduced after being pre-treated by different processes, and particles with sizes ranging from 0.5 to 3.5 μm and larger than 13.5 μm were effectively removed by RPAS. UF coupled with RPAS pre-treatment got the best removal for DOM compared to other processes with average DOC and UV254 removal 54.1% and 47.2% due to the high removal in the influent of UF. The residual alum content in the effluent of RPAS with UF was less than coagulation and bacteria were almost all removed by membrane. The membrane-fouling was mitigated by pre-treatment processes at different degrees, TMP of UF coupled with RPAS process was relatively stable in 15 d of run, the adsorption of PAC and large number of Al(OH)3 complexes and precipitates for the foulant molecules might be an important mechanism. 相似文献
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Krapal AM Popa OP Iorgu EI Costache M Popa LO 《International journal of molecular sciences》2012,13(2):2515-2520
The invasive softshell clam (Mya arenaria Linnaeus, 1758) is native to the northwestern region of the Atlantic Ocean. This species has been introduced in the northeast Pacific and along the European coasts, due to intense naval transports and aquaculture, and it is now present in all the European seas. In this paper we describe seven new microsatellite loci for Mya arenaria. The isolated loci are polymorphic with a number of alleles per locus between 6 and 14. The observed and expected heterozygosities ranged from 0.417 to 0.951, and from 0.643 to 0.895, with an average of 0.716 and 0.775, respectively. These microsatellite markers should be useful in analyzing this species' genetic diversity, which could explain various processes of its invasion history. 相似文献
13.
Shakiba Naeimi 《分离科学与技术》2017,52(18):2899-2908
In this research, metal-organic framework MOF(HKUST-1) was synthesized, magnetized and modified by hexacyanoferrate in order to prepare an efficient adsorbent for the removal of Sr2+ from aqueous solutions. The synthesized adsorbent was characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy, thermal methods (TG-DTG[Themogravimetry- Derivative Theromogravimetry]), Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area and scanning electron microscopy (SEM). The non-magnetized (MOF/KNiFC[potassium nickel hexacyanoferrate]) and magnetized (MOF/Fe3O4/KNiFC) adsorbents were then employed for the removal of Sr2+ from aqueous solutions. The adsorption capacity of 110 and 90 mg.g?1 was obtained, respectively, for MOF/KNiFC and MOF/Fe3O4/KNiFC. The adsorption process was kinetically fast and the equilibration was established within 45 min. The magnetic capability of the adsorbent examined by the vibrating sample magnetometer (VSM) technique indicated that the used adsorbent was capable of separating from the solution by applying an external magnetic field. The adsorbent showed good selectivity toward Sr2+ in the presence of Cs+, Na+, Mg2+, Ca2+ and Ba2+. The regenerated adsorbent retained more than 90% of its initial capacity. Different isotherm models including Langmuir, Freundlich, Tempkin, Sips and Redlich–Peterson were employed to examine the applicability of the isotherms to the experimental data. It was concluded that the data was best fitted to the Langmuir isotherm model. The thermodynamic parameters showed that the process was endothermic. 相似文献
14.
Bernab L. Rivas Eduardo Pereira Paola Gallegos Daniela Homper Kurt E. Geckeler 《应用聚合物科学杂志》2004,92(5):2917-2922
A water‐soluble polymer containing phosphonic acid groups was investigated as a polychelatogen by using the liquid‐phase polymer‐based retention technique (LPR) under different experimental conditions. The maximum retention capacity of this polymer was determined at different pHs and polymer–metal ion ratios. The metal ions investigated were Ag(I), Cu(II), Co(II), Ni(II), and Cr(III). The maximum retention capacity values of the divalent metal ions were very similar and higher than those for the trivalent cations, indicating that the polymer–metal ion interaction was basically through electrostatic type. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2917–2922, 2004 相似文献
15.
Front Cover: Synthesis,Crystallization Studies,and in vitro Characterization of Cinnamic Acid Derivatives as SmHDAC8 Inhibitors for the Treatment of Schistosomiasis (ChemMedChem 15/2018)
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Theresa Bayer Dr. Alokta Chakrabarti Dr. Julien Lancelot Dr. Tajith B. Shaik Kristin Hausmann Jelena Melesina Karin Schmidtkunz Dr. Martin Marek Dr. Frank Erdmann Dr. Matthias Schmidt Dr. Dina Robaa Dr. Christophe Romier Dr. Raymond J. Pierce Prof. Dr. Manfred Jung Prof. Dr. Wolfgang Sippl 《ChemMedChem》2018,13(15):1488-1488
16.
Earlier work on the group contribution method applied to the Kihara potential is extended to polyatomic gases for the calculation
of second virial coefficients, viscosities and diffusivities of dilute gases with a single set of gas group parameters. Functional
group parameters are evaluated from the simultaneous regression of second virial coefficient and viscosity data of pure gases.
Parameters for gas groups (F2, Cl2, CS2, H2S, NO, nd N2O) are found to provide good predictions of second virial cross coefficients, mixture viscosities and binary diffusion coefficients
of gas-gas mixtures. Application of the model shows that second virial coefficient data can be represented with good results
comparable to the values by means of the corresponding states model. The reliability of the present model in viscosity predictions
is proved by comparison with the Lucas method. Predictions of binary diffusion coefficients are in excellent agreement with
experimental data and compare well with values obtained by means of the Fuller method. 相似文献
17.
This paper presents a cleaner production process for producing metal stearates particles using solid-state reaction at low temperatures. Zinc stearate and lead stearate were synthesized using PbO, ZnO and stearate acid as the reactants. The products were characterized by XRD, TG, DSC and FTIR techniques. The results showed this process yielded the products in excellent yield. Compared with precipitation or saponifying process, metal stearates prepared in this way appear of shorter process, lower cost, and no production of polluted water and higher yields. 相似文献
18.
Martina Casarin Tiago Moderno Fortunato Saima Imran Martina Todesco Deborah Sandrin Giulia Borile Ilaria Toniolo Massimo Marchesan Gino Gerosa Andrea Bagno Filippo Romanato Emanuele Luigi Carniel Alessandro Morlacco Fabrizio Dal Moro 《International journal of molecular sciences》2022,23(5)
Bladder cancer (BC) is among the most common malignancies in the world and a relevant cause of cancer mortality. BC is one of the most frequent causes for bladder removal through radical cystectomy, the gold-standard treatment for localized muscle-invasive and some cases of high-risk, non-muscle-invasive bladder cancer. In order to restore urinary functionality, an autologous intestinal segment has to be used to create a urinary diversion. However, several complications are associated with bowel-tract removal, affecting patients’ quality of life. The present study project aims to develop a bio-engineered material to simplify this surgical procedure, avoiding related surgical complications and improving patients’ quality of life. The main novelty of such a therapeutic approach is the decellularization of a porcine small intestinal submucosa (SIS) conduit to replace the autologous intestinal segment currently used as urinary diversion after radical cystectomy, while avoiding an immune rejection. Here, we performed a preliminary evaluation of this acellular product by developing a novel decellularization process based on an environmentally friendly, mild detergent, i.e., Tergitol, to replace the recently declared toxic Triton X-100. Treatment efficacy was evaluated through histology, DNA, hydroxyproline and elastin quantification, mechanical and insufflation tests, two-photon microscopy, FTIR analysis, and cytocompatibility tests. The optimized decellularization protocol is effective in removing cells, including DNA content, from the porcine SIS, while preserving the integrity of the extracellular matrix despite an increase in stiffness. An effective sterilization protocol was found, and cytocompatibility of treated SIS was demonstrated from day 1 to day 7, during which human fibroblasts were able to increase in number and strongly organize along tissue fibres. Taken together, this in vitro study suggests that SIS is a suitable candidate for use in urinary diversions in place of autologous intestinal segments, considering the optimal results of decellularization and cell proliferation. Further efforts should be undertaken in order to improve SIS conduit patency and impermeability to realize a future viable substitute. 相似文献
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Mechanistic kinetic models were formulated based on Langmuir-Hinshelwood-Hougen-Watson and Eley-Rideal approaches to describe the kinetics of hydrogen production by the catalytic reforming of concentrated crude ethanol over a Ni-based commercial catalyst at atmospheric pressure, temperature range of 673-863 K, ratio of weight of catalyst to the molar rate of crude ethanol 3472-34722 kg cat s/kmol crude in a stainless steel packed bed tubular microreactor. One of the models yielded an excellent degree of correlation, and was selected for the simulation of the reforming process which used a pseudo-homogeneous numerical model consisting of coupled material and energy balance equations with reaction. The model was solved using finite elements method without neglecting the axial dispersion term. The crude ethanol conversion predicted by the model was in good agreement with the experimental data (AAD%=4.28). Also, the predicted concentration and temperature profiles for the process in the radial direction indicate that the assumption of plug flow isothermal behavior is justified within certain reactor configurations. However, the axial dispersion term still contributed to the results, and thus, cannot be neglected. 相似文献
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In the past year, emission-tunable crystals based on the rare-earth (RE) ions as luminescent center have been frequently reported for use in UV and blue converted white LEDs, but so far tuning the non-RE Bi3+ related emissions through the crystal field modulation is still not discovered in the perovskite crystals. In this work, we design and report a type of Bi3+ doped La2(Znx,Mg1-x)TiO6 (0 ≤ x ≤ 1) perovskite solid solutions, which enable showing the tunable Bi3+ excitation and emission positions. The XRD results show that gradual substitution of smaller Mg2+ ions with larger Zn2+ ions can lead to the blue-shifting of X-ray diffraction (XRD) position, revealing the expansion of cell lattice. Together with structural analysis, our refined XRD and time-resolved spectral results reveal that there is only one type of La site available for Bi3+ substitution. With this regular crystal lattice change, the crystal field strength around Bi3+ ions is found to vary regularly, allowing to realization of the excitation and emission spectral tuning, i.e., the Bi3+ excitation and emission positions as the Mg ions are replaced by the Zn ions can tune from 348?nm to 392?nm and from 405?nm to 433?nm, respectively. This Bi3+ spectral tuning peak after calculated by the dielectric chemical bond theory features a linear relationship with the crystal field strength and, thus, is ascribed to the crystal field modulation. On basis of the La2(Zn0.4,Mg0.6)TiO6 blue, SrGa2S4:Eu2+ green and Y2O3:Eu3+ red phosphors, a UV converted warm white LED device with desirable color rendering index (CRI) of 78, correlated color temperature (CCT) of 3650 K and good luminous efficacy of 118.13?lm/W, is fabricated. This work provides new insights into using the crystal-field modulation to discover more Bi3+ emission-tunable crystals for white LEDs in the future. 相似文献