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1.
Ali Shokuhi Rad Saeed Ghasemi Ateni Habib-allah Tayebi Peiman Valipour Vahid Pouralijan Foukolaei 《Journal of Sulfur Chemistry》2016,37(6):622-631
Interaction of SOx (x?=?2,3) molecules on active sites of dianiline (as a model for polyaniline, denoted here as 2PANI) was studied using density functional theory at the BLYP-D/6-31+G(d) level of theory. Natural population analysis was used to find out the charge distribution as well as the net transferred charge of SOx upon adsorption on 2PANI and the result has been compared with Mulliken charge analysis to evaluate the sensing ability of 2PANI. The computed density of states point to the remarkable orbital hybridization between SOx and 2PANI during the adsorption process. As a consequence, the results of UV–VIS confirm the sensing ability of 2PANI toward SO2 and SO3. Based on our results, it can be found that at proper configuration the SO2 and SO3 molecules can be adsorbed on 2PANI with adsorption energies (Eads) of ?18.2 and ?62.9?kJ/mol (BSSE), respectively. 相似文献
2.
《Ceramics International》2023,49(16):26516-26529
Sulfur dioxide (SO2) is one of the main harmful gas in agricultural greenhouse. Its concentration can effectively reflect the health status of plants in agricultural greenhouse. In this paper, the adsorption characteristics of SO2 on modified graphene-based were studied in comparison. The adsorption models of epoxy grouped graphene (G-O), palladium doped graphene (Pd-G) and epoxy and palladium co-doped graphene (Pd-G-O) to SO2 were established based on the first-principles, analyzing in terms of adsorption energy, density of states, orbitals, charge density and desorption time of the adsorption models. The results showed that Pd-G-O exhibited strong chemisorption with adsorption energy of -1.237 eV. Furthermore, three modified graphene-based sensing materials were prepared via the redox method in this paper, and their crystal morphology and chemical elemental composition were investigated by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. The response performance of the graphene-based sensor to SO2 was tested by a gas-sensitive testbed. The test results confirmed that the response of the Pd-G-O sample to 50 ppm SO2 at room temperature was 10.5 (1.567 and 1.235 times than that of G-O, Pd-G). Pd-G-O provides theoretical basis and experimental support for the development of a highly sensitive and fast response sensor for the detection of harmful gases in agricultural greenhouse. 相似文献
3.
《Journal of Sulfur Chemistry》2013,34(6):660-671
In this research, hydrogen sulfide is adsorbed on amido-functionalized reduced graphene oxide (AFRGO) as a nanoadsorbent. By the use of n-propylamine and allylamine, reduced graphene oxide (RGO) was amidated for the adsorption of hydrogen sulfide. The materials were characterized by adsorption of H2S, potentiometric titration, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) analysis. The effect of the operational conditions of 4000–6000 h?1 space velocities and 60,000?ppm H2S feed concentrations were examined on adsorption capacity. The results show that H2S feed concentration, space velocity, and functional groups of adsorbents have a major effect on H2S adsorption. It was also found that the temperature in the range of 30–70°C had a significant effect on H2S adsorption. The concentration of H2S adsorbed in 3?h by AFRGO containing allyl substituent, AFRGO containing propyl substituent, graphene oxide (GO), and reduced graphene oxide (RGO) were reported as 59,710, 59,650, 59,600, and 59,500?ppm, respectively. Hydrogen sulfide adsorption analysis showed that nanoadsorbents increase adsorption capacity of H2S. 相似文献
4.
First principles calculations within density functional theory have been carried out to investigate the adsorptions of SOx (x?=?1, 2) molecules on TiO2/MoS2 nanocomposites in order to fully discover the gas sensing capabilities of TiO2/MoS2 composite systems. The van der Waals interactions were included to obtain the most stable geometrical structures of TiO2/MoS2 nanocomposites with adsorbed SOx molecules. SOx molecules preferentially interact with the doped nitrogen and fivefold coordinated titanium sites of the TiO2 anatase nanoparticles because of their higher activities in comparison with the other sites. The results presented include structural parameters such as bond lengths and bond angles and energetics of the systems such as adsorption energies. The variation of electronic structures are discussed in view of the density of states and molecular orbitals of the SOx molecules adsorbed on the nanocomposites. The results show that the adsorption of the SOx molecule on the N-doped TiO2/MoS2 nanocomposite is energetically more favorable than the adsorption on the undoped one, implying that the nitrogen doping helps to strengthen the interaction of SOx molecules with TiO2/MoS2 nanocomposites. These calculated results thus provide a theoretical basis for the potential applications of TiO2/MoS2 nanocomposites in the removal and sensing of harmful SOx molecules. 相似文献
5.
In this study, graphene oxide (GO) is chemically reacted with sodium borohydride (NaBH4) to form reduced graphene oxide (rGO). rGO, polycarbazole (PCz)/rGO and PCz/nanoclay/rGO materials were obtained by chemical polymerisation method. These three materials were characterised by Fourier-transform infra-red spectroscopy-attenuated transmission reflectance, scanning electron microscopy, energy-dispersive X-ray analysis, cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy. The PCz/nanoclay/rGO nanocomposite shows significantly improved capacitance (Csp?=?187.78?F?g?1) compared to that of PCz/rGO (Csp?=?74.18?F?g?1) and rGO (Csp?=?20.78?F?g?1) at the scan rate of 10?mV?s?1 by CV method. The supercapacitor device performance results show high power density (P?=?1057.81?W?kg?1) and energy density (E?=?1.7?Wh?kg?1) obtained from Ragone plot for PCz/nanoclay/rGO material. Stability tests were also examined by the CV method for 1000 cycles. 相似文献
6.
Effect of graphene oxide on the behavior of poly(amide‐6‐b‐ethylene oxide)/graphene oxide mixed‐matrix membranes in the permeation process
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Polyether‐block‐amide (Pebax)/graphene oxide (GO) mixed‐matrix membranes (MMMs) were prepared with a solution casting method, and their gas‐separation performance and mechanical properties were investigated. Compared with the pristine Pebax membrane, the crystallinity of the Pebax/GO MMMs showed a little increase. The incorporation of GO induced an increase in the elastic modulus, whereas the strain at break and tensile strength decreased. The apparent activation energies (Ep) of CO2, N2, H2, and CH4 permeation through the Pebax/GO MMMs increased because of the greater difficulty of polymer chain rotation. The Ep value of CO2 changed from 16.5 kJ/mol of the pristine Pebax to 23.7 kJ/mol of the Pebax/GO MMMs with 3.85 vol % GO. Because of the impermeable nature of GO, the gas permeabilities of the Pebax/GO MMMs decreased remarkably with increasing GO content, in particular for the larger gases. The CO2 permeability of the Pebax/GO MMMs with 3.85 vol % GO decreased by about 70% of that of the pristine Pebax membrane. Rather than the Maxwell model, the permeation properties of the Pebax/GO MMMs could be described successfully with the Lape model, which considered the influence of the geometrical shape and arrangement pattern of GO on the gas transport. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42624. 相似文献
7.
A conventional NO
x
-trap catalyst containing platinum, rhodium, barium and lanthanum was conditioned with oxygen at 500°C, preloaded with NO under standard oxidising conditions and then subjected to regeneration with the reductants H2, CO and C3H6, either alone or as a mixture. Hydrogen is the most efficient reductant in terms of NO
x
conversion efficiency and reductant usage efficiency. There is a temperature optimum for CO between 300 and 400°C and a catalyst loading optimum (mols reductant added)/(mols NO
x
adsorbed) between 1.5 and 3.0. The behaviour of the catalyst towards sulphur poisoning was examined in supplementary trials with the adsorption of SO2 in the presence or absence of water vapour. When water is not present in both adsorption and reduction steps, very stable sulphates are formed, unattacked by reductants even at 1000°C. Sulfates are more easily reduced when water is present in the reductant mixture. 相似文献
8.
We report the development of TiO2/graphene/poly(acrylamide) superporous hybrid by a radical polymerization reaction and explore its environmental application as photocatalyst of organic pollutants. During the polymerization reaction, graphene nanosheets and TiO2 nanoparticles homogeneously distribute on the hydrogel, in which TiO2 nanoparticles with a uniform size are densely anchored onto graphene and self-assembled into different structures with various graphene contents. The resultant TiO2/graphene/poly(acrylamide) superporous hybrid experiences tremendous adsorption toward dye pollution before photodegradation, and it also displays similar photodecomposition efficiency with pristine TiO2. Moreover, the TiO2/graphene/poly(acrylamide) superporous hybrid is recyclable, which demonstrates the potential of hybrid as an attractive photocatalyst for wastewater treatment. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47033. 相似文献
9.
Graham P. Ansell Stanislaw E. Golunski Helen A. Hatcher Raj R. Rajaram 《Catalysis Letters》1991,11(2):183-190
Over current Pt-Rh/CeO2-Al2O3 catalysts, the conversion of alkanes occurs by two principal mechanisms: direct oxidation (HC + O2) and steam reforming (HC+H2O). Sulphur dioxide can influence both these mechanisms. Direct oxidation, which predominates when the exhaust-gas is fuel-lean, ispromoted by the adsorption of SOx species by the support. Under fuel-rich atmospheres, the presence of SO2 severelyinhibits steam reforming. The poisoning is associated with the formation of S2– on the platinum and of SO
4
2–
on the support, but there is no indication of S-species being retained by the rhodium. It is proposed that each of the two mechanisms is sensitive to a different type of interaction at the metal-support interface. Direct oxidation is enhanced by the transfer of electrons from the precious metal to the support; steam reforming occurs at interfacial sites, which can be blocked by adsorbed SOx species. 相似文献
10.
《Gas Separation & Purification》1993,7(1):19-25
A new material, mordenite synthesized from volcanic ash (perlite) in the presence of sodium salts, has been shown to be a weak sorbent for NO and a strong and reversible sorbent for SO2. The mordenite's capacity to adsorb SO2 was found to be related to the amount of sodium present in the material. Capacities as high as 8 wt% were achieved at 1250 ppm of SO2 in helium at 25°C. In multicycle tests the mordenite maintained its capacity after more than 40 cycles when desorbing the SO2 at 300°C. The adsorption rate of SO2 in the absence of water was modelled and the adsorption activation energy was found to be 3.2 kcal mol−1. Water significantly decreased the mordenite's capacity to adsorb SO2 and also caused the SO2 to be chromatographically desorbed in a roll-up peak. In these water-SO2 adsorption experiments a peculiar breakthrough was observed for water, where the water concentration exiting the bed first decreased and then increased. This peculiar water breakthrough could not be explained by assuming independent adsorption of the two species, but was qualitatively predicted by assuming that water adsorption is enhanced by the presence of adsorbed SO2. 相似文献
11.
《分离科学与技术》2012,47(1):10-16
A series of MgAlFeCu mixed oxides with different chemical compositions derived from hydrotalcite-like compounds were prepared by the NaAlO2-coprecipitation method and characterized by XRF, XRD, and N2 adsorption analysis. These sulfur-transfer catalysts were evaluated as SOx removal catalysts under the conditions similar to those of FCC units. The results showed that the total SO2 adsorption amounts increased with increasing magnesium content. And the redox properties of Fe2O3 enhanced significantly the adsorption-reduction capacities of the catalysts, while CuO can be used as an effective oxidation promoter. Furthermore, the catalyst LDOs-6 (Mg/Al = 6, Fe2O3% = 8% and CuO% = 1%) presented the excellent SO2 removal capacity, its total amounts of adsorbed SO2 reached 1.74 g /g in 7 min, which also remained constant after eight cycles. These results indicated that the performances of the catalysts were closely related to the chemical composition. 相似文献
12.
M. Metikoš-Hukovič R. Babić Z. Grubač S. Brinić 《Journal of Applied Electrochemistry》1996,26(4):443-449
The inhibitive action of thiourea on the corrosive behaviour of ARMCO iron was investigated in deaerated 0.5 M H2SO4 solution, by means of electrochemical impedance spectroscopy. The inhibitor effectiveness increases with concentration, reaches a maximum (at about 1 mm) and then decreases. The adsorptive behaviour of thiourea on the electrode surface up to its peak follows a Frumkin-type isotherm with lateral repulsion, where the molecules are vertically adsorbed on the iron surface via the sulfur atom. Thiourea acts as a mixed inhibitor up to the critical concentration. It decreases the dissolution of iron and the hydrogen evolution reaction by blocking the electrode surface. The free energy of adsorption ΔG ad = ?39 kJ mol?1 and the attraction constant a = ?4.4. 相似文献
13.
K. P. Yadava B. S. Tyagi V. N. Singh 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(1):47-60
The removal of Pb(II) from aqueous solution by adsorption on china clay and wollastonite is an attractive process. The amount of Pb(II) removed by adsorption is highly dependent on the temperature of the adsorbate solution and favours low temperature. The equilibrium times were noted, i.e. 90 min for china clay and 120 min for wollastonite. The various rate parameters of the adsorption process have been determined at different temperatures. The activation energies were determined and found to be ?5.345 kJ mol?1 and ?8.730 kJ mol?1 for Pb(II)-china clay and Pb(II)-wollastonite systems, respectively. The adsorption isotherm was measured experimentally at various temperatures. The negative values of enthalpy change (ΔH = ?77.95 kJ mol?1 and ?16.40 kJ mol?1 for china clay and wollastonite, respectively) indicate the exothermic nature of the adsorption processes for both systems. The isosteric heats of the adsorption process have been determined at various surface coverages of the adsorbents used. The various thermodynamic parameters have been calculated to elucidate the mechanism involved in the adsorption process. 相似文献
14.
The two‐dimensional coordination polymer cadmium phosphate with the morphology of rectangle layers was prepared by solid‐state template reaction at room temperature, and was characterized by XRD, FTIR, and TEM techniques. The as‐synthesized sample is a layered cadmium phosphate material, in which the structure is poly (CdPO4?) anion framework with ammonium ions and water species residing in the space between the layers, and cadmium ions are coordinated by the phosphate oxygen atoms. This article also presents the adsorption of Pb(II) ions from aqueous solution on the as‐synthesized coordination polymer cadmium phosphate, and the results showed that this inorganic polymer adsorbent had good adsorption capacity. It could reach to the saturation adsorption capacity within an hour, and its excellent adsorption capacity for Pb(II) was 5.50 mmol/g when the initial solution concentration was 1.68 × 103 μg/mL at T = 278K. Moreover, the adsorption kinetics and adsorption isotherms were studied, it revealed that the adsorption kinetics can be modeled by pseudo second‐order rate equation wonderfully. The apparent activation energy (Ea), ΔG, ΔH, and ΔS were 3.16 kJ mol?1, ?13.97 kJ mol?1, ?11.84 kJ mol?1, and 7.66 J mol?1 K?1, respectively. And it was found that Langmuir equation could well interpret the adsorption of the as‐synthesized coordination polymer cadmium phosphate for Pb(II) ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
15.
Markus Happel Lisa Kylhammar Per-Anders Carlsson Jrg Libuda Henrik Grnbeck Magnus Skoglundh 《Applied catalysis. B, Environmental》2009,91(3-4):679-682
The SOx storage and release kinetics on CeO2 have been studied by lean SOx adsorption and temperature programmed desorption for different pairwise configurations of individual monolith samples, i.e., Pt/CeO2 + SiO2, Pt/SiO2 + CeO2, CeO2 + Pt/SiO2 and CeO2 + SiO2. In the case of sole ceria, SOx adsorption proceeds both via SO2 and SO3 adsorption although the latter channel is kinetically favored. Hence, the rate of SO2 oxidation is crucial for the overall SOx storage kinetics. It is also found that physical contact between Pt and ceria is important for the storage process. This is attributed to efficient transport routes for SOx (surface diffusion and spill-over processes) and/or specific adsorption sites at the platinum–ceria interface. The main route for SOx release is found to be thermal decomposition where the effect of platinum is minor, although an indirect effect cannot be ruled out. Different mechanistic scenarios for SOx adsorption are discussed, which may serve as a guide for future experiments. 相似文献
16.
Jordana Georgin Dison S. P. Franco Fernanda C. Drumm Patrícia Grassi Matias Schadeck Netto Daniel Allasia 《Chemical Engineering Communications》2020,207(10):1368-1379
AbstractThe powdered biomass of paddle cactus (Tacinga palmadora), a rustic plant of great occurrence in the driest regions of Brazil, was evaluated as a low-cost adsorbent to treat textile effluents containing crystal violet (CV) dye. The powdered paddle cactus (PPC) was mainly composed by lignin and holocellulose, as well as, a variety of functional groups. Best results for CV adsorption were found using an adsorbent dosage of 0.5?g L?1 at solution pH equivalent to 10.0. Fast adsorption kinetics was verified, being the equilibrium reached within 100?min, and the curves were well modeled by the pseudo-first-order model. The isotherms were well-represented by the Langmuir model. The maximum adsorption capacity was 228.74?mg g?1 at 328?K. The estimated thermodynamics parameters were ΔG0T?=?328K of –9.08?kJ mol?1, ΔH0 of 12.44?kJ mol?1, and ΔS0 of 0.065?kJ mol?1 K?1. In addition, PPC was able to treat a simulated textile effluent containing organic and inorganic compounds, reaching 93% of color removal efficiency. These findings show that powdered paddle cactus can be applied as potential low-cost adsorbent to treat textile effluents containing CV. 相似文献
17.
《Ceramics International》2022,48(17):24979-24988
In search of better materials for visible light photocatalytic performance, perovskite Sr0.3(Ba/Mn)0.7ZrO3 nanopowders anchored on graphene oxide were synthesized for the evaluation of their photocatalytic activity against methylene blue (MB). The chemical coprecipitation method was used to synthesize SrZrO3 (SZO) and a series of doped derivatives having a nominal composition of Sr1-x(Ba,Mn)xZrO3 (x = 0.1–0.9) at an annealing temperature of 700 °C for 12 h. However, Sr0.3(Ba,Mn)0.7ZrO3 with a bandgap value of 3.50 eV was further processed for the formation of composite with graphene oxide (GO) owing to its lowest bandgap value in the synthesized series. The inclusion of larger Ba2+ cations in the lattice resulted in the redistribution of cations creating antisite defects which were evident from the shrinkage of the lattice. The incorporation of Mn2+ resulted in the hybridization of Mn2+ (3d) orbitals with the split Zr4+ (4d) orbitals. This reduced the bandgap and composite formation with GO further enhancing the delocalization of excited electrons to GO hence, reducing electron-hole recombination. Adsorption assisted photocatalysis under a 100 W tungsten lamp was performed using the designed catalysts for the removal/degradation of MB. The π-π conjugation and the ionic interactions were found responsible for the adsorption of MB at the GO surface. High surface coverage, initial dye concentrations, heterogeneous catalyst surface, weak van der Waals interactions, pH and availability of ?OH radicals were found to be the decisive factors for the removal/degradation process. Improved charge separation enhances the generation of ?OH and better performance of the GO composites as opposed to the pristine strontium zirconate perovskites. 相似文献
18.
Seung-Ho Jung Gwi-Taek Jeong Gwang-Yeon Lee Jin-Myeong Cha Don-Hee Park 《Korean Journal of Chemical Engineering》2007,24(6):1064-1069
SO
x
and NO
x
have both previously been identified as primary precursors of acid rain, and thus the abatement of SO
x
and NO
x
emissions constitutes a major target in the field of air pollution control. In this study, the efficacy of a pilot-scale
scrubber was evaluated with regard to the simultaneous removal of SO2, NO and particulate with wet catalysts. The removal efficiencies of particulate were measured to be 83, 92 and 97% with catalyst
flux of 0.5, 0.8 and 1.5 L/min, respectively. The average removal efficiencies of particulate with different nozzles were
approximately 94 and 90% with FF6.5 (5/8 in.) and 14 W (1.0 in.) nozzles, respectively. At least 96–98% of particulate and
SO2 were removed, regardless of the stage number of reactor. In a one-stage scrubber, 83.3% removal efficiency of NO was achieved
after 48 hours; however, the two-stage scrubber achieved an NO removal efficiency of 95.7%. Regardless of the liquid-gas ratio,
SO2 and particulate were removed effectively, whereas NO was removed about 84% and 74% under liquid-gas ratio conditions of 39.32
L/m3 and 27.52 L/m3, respectively. In experiments using STS and P.P. pall ring as packing material, particulate and SO2 removal efficiency values in excess of 98% were achieved; however, NO removal was correlated with the different packing materials
tested in this study. With the above optimum operation conditions, even after 20 hours, the removal efficiency for NO stayed
at 95% or higher, the removal efficiency for SO2 stayed at 97% or higher, and the removal efficiency for particulate stayed at 92% or higher. In accordance, then, with the
above results, it appears that this process might be utilized in scrubber systems, as well as systems designed to simultaneously
remove particulate, SO2 and NO from flue gas. 相似文献
19.
Simulation techniques have been employed to investigate the differences in the low energy adsorption configurations of ethene and ethane on the TiO2 supported and unsupported V2O5(001) surface. We find that the ethene molecule approaches much closer to thesupported V2O5(001) surface which is reflected in the 40 kj mol–1 higher adsorption energy. The low energy adsorption configuration located for ethane on the supported V2O5 shows that the molecule does not approach as close to the supported V2O5 surface as does ethene, resulting in the adsorption energy of ethane being 52 kJ mol–1 lower than that of ethene on the supported V2O5 surface. 相似文献
20.
Supramolecular recognition of functional magnesium tetraphenylporphyrin (MgTPP) with pyrrolidine for SO2 capture was investigated in CH2Cl2 by steady-state fluorescence and UV-vis absorption spectroscopic techniques. The UV-vis spectra showed that the interaction of MgTPP with pyrrolidine resulted in red shift of 2 nm for MgTPP Soret absorption band. Once introduced, SO2 competes with MgTPP for pyrrolidine, which eventually leads to the release of MgTPP. The fluorescence spectra suggested that MgTPP interacted with pyrrolidine to form 1: 1 molecular adducts, and showed that the binding of MgTPP with pyrrolidine with the association constants (Kassoc) of (0.86 to 1.19) is not only exothermic but enthalpy-driven with ΔH=?15.805 kJ mol?1, ΔS=?52.727 J mol?1 K1, and ΔG=?214.444 J mol?1 at T=296.15 K. 相似文献