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1.
A facile and novel strategy for preparing mesoporous crystalline copper–polyaniline composite is reported wherein the reaction is carried out at room temperature using copper nitrate as the oxidizing agent and methanol as the solvent. The composite obtained as a precipitate has been characterized using UV–visible absorption spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption–desorption method, Barrett–Joyner–Halenda (BJH) method, Brunauer–Emmett–Teller method (BET) and thermogravimetric analysis (TGA). The XRD studies in conjunction with the BJH method reveals that the composite has crystalline nature with a mesoporous structure and has a diameter of 3.5 nm. The specific surface area of copper–polyaniline composite is estimated to be as high as 63.2 m2 g?1 using the BET surface area plot. The characterization of the filtrate indicates the presence of pernigraniline with a very small weight percent of copper.  相似文献   

2.
The adsorption of uranium (VI) from aqueous solutions onto natural sepiolite has been studied using a batch adsorber. The parameters that affect the uranium (VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, and temperature, have been investigated and optimized conditions determined. Equilibrium isotherm studies were used to evaluate the maximum sorption capacity of sepiolite and experimental results showed this to be 34.61 mg · g?1. The experimental results were correlated reasonably well by the Langmuir adsorption isotherm and the isotherm parameters (Qo and b) were calculated. Thermodynamic parameters (ΔH° = ?126.64 kJ · mol?1, ΔS° = ?353.84 J · mol?1 · K?1, ΔG° = ?21.14 kJ · mol?1) showed the exothermic heat of adsorption and the feasibility of the process. The results suggested that sepiolite was suitable as sorbent material for recovery and adsorption of uranium (VI) ions from aqueous solutions.  相似文献   

3.
《Solid State Sciences》2012,14(2):250-257
CO2 adsorption properties on Mg modified silica mesoporous materials were investigated. By using the methods of co-condensation, dispersion and ion-exchange, Mg2+ was introduced into SBA-15 and MCM-41, and transformed into MgO in the calcination process. The basic MgO can provide active sites to enhance the acidic CO2 adsorption capacity. To improve the amount and the dispersion state of the loading MgO, the optimized modification conditions were also investigated. The XRD and TEM characteristic results, as well as the CO2 adsorption performance showed that the CO2 adsorption capacity not only depended on the pore structures of MCM-41 and SBA-15, but also on the improvement of the dispersion state of MgO by modification. Among various Mg modified silica mesoporous materials, the CO2 adsorption capacity increased from 0.42 mmol g−1 of pure silica SBA-15 to 1.35 mmol g−1 of Mg–Al–SBA-15-I1 by the ion-exchange method enhanced with Al3+ synergism. Moreover, it also increased from 0.67 mmol g−1 of pure silica MCM-41 to 1.32 mmol g−1 of Mg–EDA–MCM-41-D10 by the dispersion method enhanced with the incorporation of ethane diamine. The stability test by 10 CO2 adsorption/desorption cycles showed Mg–urea–MCM-41-D10 possessed quite good recyclability.  相似文献   

4.
A novel [Cu(bpdo)2·2H2O]2+-supported SBA-15 catalyst (bpdo = 2,2′-bipyridine,1,1′-dioxide) was prepared by the impregnation method. The catalyst was characterized by XRD, TEM, and BET nitrogen adsorption–desorption method, FT-IR, UV–vis, and chemical analysis. XRD patterns and TEM analysis of [Cu(bpdo)2·2H2O]2+/SBA-15 showed highly ordered hexagonal mesoporous silica, even after immobilization. Also, nitrogen adsorption–desorption isotherms exhibited type-IV isotherms and H1 hysteresis loops according to the IUPAC classification of mesoporous materials. This green support was tested for the synthesis of benzoxanthenone and benzochromene derivatives under solvent-free conditions, with high yield of products via a simple experimental and work-up procedure.  相似文献   

5.
The present work aims to conduct a process optimization for the production of activated carbon from sludge of food processing industry. The significant feature of this sludge based activated carbon that makes it unique and economic is that it can be produced from waste material. The carbonaceous nature of this sludge does not allow its direct disposal to land because of excess organic and nutrient load contents, however, can be converted to a value added product. This process not only eliminates the need for further treatment of sludge but also reduce the cost of its handling, land filling, and transportation as well as the utilization in the same industry in the purification system.In the present work, activated carbon produced from pyrolysis of sludge was chemically activated by various activating agents. Optimization of impregnation ratio, impregnation time, activation temperature, and activation time was studied. The product was characterized through its iodine value and yield percentage. It was observed that the product had maximum iodine value of 624 mg g−1 with ZnCl2 as an activating agent. The FT-IR analysis depicts the presence of a variety of functional groups attached on the surface of activated carbon which are used in the interaction with the adsorbate during the process of adsorption. The XRD analysis reveals that the produced activated carbon has low content of inorganic constituents compared with the precursor. The product formed was applied for methylene blue adsorption. The adsorption equilibrium of methylene blue dye was examined at room temperature. Adsorption isotherm was drawn by applying Langmuir and Freundlich models fitting the data indict, with an adsorption capacity of 23.6 mg g−1 and 14.2 mg g−1, respectively. The data show that methylene blue adsorption is best suited to Langmuir equation.  相似文献   

6.
Nano-sized nickel ferrite (NiFe2O4) was prepared by hydrothermal method at low temperature. The crystalline phase, morphology and specific surface area (BET) of the resultant samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and nitrogen physical adsorption, respectively. The particle sizes of the resulting NiFe2O4 samples were in the range of 5–15 nm. The electrochemical performance of NiFe2O4 nanoparticles as the anodic material in lithium ion batteries was tested. It was found that the first discharge capacity of the anode made from NiFe2O4 nanoparticles could reach a very high value of 1314 mAh g−1, while the discharge capacity decreased to 790.8 mAh g−1 and 709.0 mAh g−1 at a current density of 0.2 mA cm−2 after 2 and 3 cycles, respectively. The BET surface area is up to 111.4 m2 g−1. The reaction mechanism between lithium and nickel ferrite was also discussed based on the results of cycle voltammetry (CV) experiments.  相似文献   

7.
A polymeric activated carbon (PAC) was synthesized from the carbonization of a resorcinol–formaldehyde resin with KOH served as an activation agent. The nitrogen adsorption–desorption at 77 K, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared PAC. Compared with the commercial activated carbon (Maxsorb: Kansai, Japan), PAC shows superior capacitive performance in terms of specific capacitance, power output and high energy density as electrode materials for supercapacitors. PAC presents a high specific capacitance of 500 F g?1 in 6 mol l?1 KOH electrolyte at a current density of 233 mA g?1 which remained 302 F g?1 even at a high current density of 4.6 A g?1. The good electrochemical performance of the PAC was ascribed to well-developed micropores smaller than 1.5 nm, the presence of electrochemically oxygen functional groups and low equivalent series resistance.  相似文献   

8.
The carbonization of coal/KOH mixtures were investigated to identify the influence of potassium distributions on characteristics of the final products. The products were characterized using TGA, BET, TEM and adsorption of lead from its aqueous solutions with initial concentrations of 10–100 ppm. For the activated carbon obtained at 600 °C, the potassium distribution affected both the BET surface areas (661–1994 m2/g) and the meso- and micro-pore volumes ratios (0.48–0.91). There were also evolutions of nanostructures of both straight and curved tubular morphologies as evidenced by TEM micrograph. The samples exhibited different adsorptive capacities when tested in adsorption of lead from aqueous solutions. The adsorption followed second order kinetics and the equilibrium data were better described by empirical Freudlich isotherm model. The amount of lead adsorbed ranges from 4.3 to 47.3 mg/g. Thus, different degrees of potassium effects led to activated carbons with different surface and adsorptive properties.  相似文献   

9.
Nanocrystalline SnO2 particles have been synthesized by a sol–gel method from the very simple starting material granulated tin. The synthesis leads a sol–gel process when citric acid is introduced in the solution obtained by dissolving granulated tin in HNO3. Citric acid has a great effect on stabilizing the precursor solution, and slows down the hydrolysis and condensation processes. The obtained SnO2 particles range from 2.8 to 5.1 nm in size and 289–143 m2 g−1 in specific surface area when the gel is heat treated at different temperatures. The particles show a lattice expansion with the reduction in particle size. With the absence of citric acid, the precursor hydrolyzes and condenses in an uncontrollable manner and the obtained SnO2 nanocrystallites are comparatively larger in size and broader in size distribution. The nanocrystallites have been characterized by means of TG-DSC, FT-IR, XRD, BET and TEM.  相似文献   

10.
In this paper, we report on the formation of novel hexagonal NiTiO3 nanopowders synthesized by the impregnation or co-precipitation methods through the thermal decomposition reaction of the precursors. The decomposition course was followed using differential thermal analysis (DTA) and thermogravimetric analysis (TGA) techniques. The intermediate decomposition products as well as the formed titanate were characterized using X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. XRD patterns of the precursors calcined at 1000 °C showed the formation of the single ilmenite-type rhombohedral structure only with the impregnated precursor, while with the precipitated NiTiO3 powders one it indicates the presence of some NiO and TiO2 impurities. Transmission electron microscopy (TEM) exhibited loosely agglomerated hexagonal particles with uniform morphology having a size around 61 nm. The Brunauer-Emmett-Teller (BET) surface area measurements showed a type III isotherm with calculated surface area of 152 m2/g. The plot of ln σac vs. temperature as a function of frequency indicates a semiconducting behavior with ferroelectric phase transition at 605 K. The calculated activation in the ferroelectric region is 0.93 eV suggests the predominance of hopping conduction mechanism. Kinetic analysis of TG data according to different integral methods showed that in the NiC2O4·2H2O–TiO2 precursor, the water molecules are coordinately bounded and the presence of TiO2 reduces the activation energy needed to the oxalate decomposition reaction.  相似文献   

11.
Producing biochar and biofuels from poultry litter (PL) through slow pyrolysis is a farm-based, value-added approach to recycle the organic waste. Experiments were conducted to examine the effect of pyrolysis temperature on the quality PL biochar and to identify the optimal pyrolysis temperature for converting PL to agricultural-use biochar. As peak pyrolysis temperature increased incrementally from 300 to 600 °C, biochar yield, total N content, organic carbon (OC) content, and cation exchange capacity (CEC) decreased while pH, ash content, OC stability, and BET surface area increased. The generated biochars showed yields 45.7–60.1% of feed mass, OC 325–380 g kg−1, pH 9.5–11.5, BET surface area 2.0–3.2 m2 g−1, and CEC 21.6–36.3 cmolc kg−1. The maximal transformation of feed OC into biochar recalcitrant OC occurred at 500 °C, yet 81.2% of the feed N was lost in volatiles at this temperature. To produce agricultural-use PL biochar, 300 °C should be selected in pyrolysis; for carbon sequestration and other environmental applications, 500 °C is recommended.  相似文献   

12.
A cost-effective successive ionic layer adsorption and reaction (SILAR) method was used to deposit copper (I) thiocyanate (CuSCN) thin films on glass and steel substrates for this study. The deposited thin films were characterized for their structural, morphological, optical and electrochemical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy and VersaSTAT potentiostat. A direct band gap of 3.88 eV and 3.6 eV with film thickness of 0.7 μm and 0.9 μm was obtained at 20 and 30 deposition cycles respectively. The band gap, microstrain, dislocation density and crystal size were observed to be thickness dependent. The specific capacitance of the CuSCN thin film electrode at 20 mV/s was 760 F g−1 for deposition 20 cycles and 729 F g−1 for deposition 30 cycles.  相似文献   

13.
A simple, sensitive, and cost-effective analytical method was developed for the speciation analysis of inorganic selenium by combining a nano-TiO2 preconcentration with an ion chromatography-conductivity detection (IC-CD) system. The experimental conditions for the simultaneous adsorption and desorption of Se(IV) and Se(VI) were carefully investigated. Under the established optimum condition, the Se(IV) and Se(VI) ions could been simultaneously adsorbed onto the nano-TiO2 surface at pH 4.0, and then effectively desorbed by 0.1 M sodium hydroxide eluent. The adsorption process was fast and reached adsorption equilibrium within 10 min. The nano-TiO2 also exhibited high adsorption capacity with 11.3 mg g? 1 for Se(IV) and 8.34 mg g? 1 for Se(VI). The enrichment factors for Se(IV) and Se(VI) were calculated to be 39 and 30, respectively, with sample volume of 50 mL. The detection limits (3σ) were 0.8 μg L? 1 for Se(IV) and 0.4 μg L? 1 for Se(VI), which were sensitive enough for the routine analysis of water and drink samples. The relative standard deviation was calculated to be < 4% (n = 6) for detection of 30 μg L? 1 Se(IV) and 30 μg L? 1 Se(VI). The results of the present work confirmed that our developed nano-TiO2-IC-CD method could be applied for the detection of inorganic selenium species in tap water and drink samples with good recoveries in the range of 82%–108%.  相似文献   

14.
Nano-TiO2 was synthesized by sol–gel method. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) images, transmission electron microscope (TEM), BET surface area measurement and DRS analysis. The formation of anatase phase nano-TiO2 was confirmed by XRD measurements and its crystalline size is found to be 15.2 nm. SEM images depict the crystalline nature of prepared TiO2. The BET surface area of prepared TiO2 is found to be 86.5 m2 g?1 which is higher than that of commercially available TiO2–P25. The photocatalytic activity of prepared anatase phase TiO2 has been tested for the degradation of two azo dyes: Reactive Red 120 (RR 120) and Trypan Blue (TB) using solar light. The photocatalytic activity of nano-TiO2 is higher than TiO2–P25 under solar light. The mineralization of dyes has been confirmed by chemical oxygen demand (COD) measurements.  相似文献   

15.
A novel composite adsorbent, silica aerogel activated carbon was synthesized by sol-gel process at ambient pressure drying method. The composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Nitrogen adsorption/desorption isotherms (BET).In the present study, the mentioned adsorbent was used moderately for the removal of cadmium ions from aqueous solutions and was compared with two other adsorbents of cadmium, activated carbon and silica aerogel. The experiments of Cd adsorption by adsorbents were performed at different initial ion concentrations, pH of the solution, adsorption temperature, adsorbent dosage and contact time. Moreover, the optimum pH for the adsorption was found to be 6.0 with the corresponding adsorbent dosage level of 0.1 g at 60 °C temperature. Subsequently, the equilibrium was achieved for Cd with 120 min of contact time.Consequently, the results show that using this composite adsorbent could remove more than 60% of Cd under optimum experimental conditions. Langmuir and Freundlich isotherm model was applied to analyze the data, in which the adsorption equilibrium data were correlated well with the Freundlich isotherm model and the equilibrium adsorption capacity (qe) was found to be 0.384 mg/g in the 3 mg/L solution of cadmium.  相似文献   

16.
《Comptes Rendus Chimie》2014,17(12):1203-1211
A thiol-functionalized hierarchical zeolite nanocomposite was synthesized and investigated with a view to remove mercury from aqueous solutions. The hierarchical zeolite was prepared by the use of a beta zeolite and of cetyltrimethylammoniumbromide (CTAB). The ligand, 3-mercaptopropyltrimethoxysilane containing thiol (–SH) groups, was then immobilized on the surface of the hierarchical zeolite through grafting with surface silanol groups. FTIR, XRD, SEM, TG-DTG, and N2 adsorption–desorption techniques were used to characterize the nanocomposite before and after functionalization. Adsorption experiments showed that this adsorbent was an excellent one to bind mercury with high selectivity; an adsorption capacity of 8.2 mequiv·g−1 of adsorbent was obtained. Furthermore, the adsorbent retained most of its capacity after regeneration with nitric acid and thiourea solutions. The adsorption data was fitted to the Freundlich isotherm.  相似文献   

17.
Anatase phase mesoporous TiO2 with I41/amd space group was synthesized via the urea assisted hydrothermal method. The existence of mono phasic TiO2 sub-microspheres of uniform particle size (ca. 400 nm) encompassing an average crystallite size of 14 nm was demonstrated using the XRD, FE-SEM and TEM analysis. Surface area of ca. 116.49 m2/g along with a pore size of 7 nm was calculated using the BET and adsorption isotherm measurements which authenticated the mesoporous nature of the synthesized material. Suitable calcination temperature for the better electrochemical property was established via the optimization process. Accordingly, the mesoporous TiO2 calcined at 400 °C displayed improved cycleability with excellent rate capability ever reported, even at 20 C-rate of discharge. The reason for the superior rate capability is corroborated to the highly mesoporous nature of the TiO2 sub-microspheres that has imparted desirable surface area apposite for enhanced ionic and electronic diffusion.  相似文献   

18.
We described a novel and eco-friendly approach to remove toxic heavy metal of Pb(II) by using dimercaptosuccinic acid (DMSA) anchored Fe3O4 magnetic nanorods (MNRs) which were synthesized via facile method utilizing Punica Granatum rind extract which was a non toxic waste material. The DMSA@Fe3O4 MNRs were characterized by X-ray diffraction (XRD), Fourier transformed infrared analysis (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), nitrogen adsorption and desorption techniques, and vibrating sample magnetometer (VSM). These DMSA@Fe3O4 MNRs have been used for the removal of Pb(II) from aqueous solution. The adsorption isotherm data fitted well with Langmuir isotherm and Freundlich model, the monolayer adsorption capacity was found to be 46.18 mg/g at 301 K. The experimental kinetic data fitted very well with the pseudo-second-order model. The results indicate that the biogenic synthesized DMSA@Fe3O4 MNRs act as significant adsorbent material for removal of Pb (II) from aqueous environment.  相似文献   

19.
Hyaluronic acid (HYH) films were prepared from aqueous sodium hyaluronate (HYNa) solutions by anodic electrodeposition. The film thickness was varied in the range of 0–20 μm by the variation of the deposition time and HYNa concentration. The deposition rate was low at HYNa concentration below 1 g L−1 and increased significantly in the range of 3–5 g L−1. The addition of bovine serum albumin (BSA) to the HYNa solutions resulted in increased deposition yield, which was attributed to the formation of composite HYH–BSA films. The thickness of the HYH–BSA films deposited by anodic electrodeposition was varied in the range of 0–80 μm. The HYH and composite HYH–BSA films were studied by scanning electron microscopy, thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy and circular dichroism spectroscopy. The deposition mechanism and kinetics of deposition are discussed.  相似文献   

20.
The fluoride adsorption by Electro-Generated Adsorbents (EGA) was briefly and recently shown. In this paper, the preparation of a particular EGA and its characteristics are presented. For the first time, the fluoride adsorption of one EGA was deeply investigated showing that the regeneration of this material leads to an efficient process which was better than an electrocoagulation one. The investigated adsorbent called EGANaCl was prepared by electrolysis in NaCl electrolyte with aluminum electrodes and was characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), FTIR and BET studies. The physical analyses showed that EGANaCl was a mesoporous mixture of AlOOH and three Al(OH)3 which contain the chlorine element and registered the surface area of 114.31 m2 g−1. The presence of chlorine explains the pH increase observed during the electrolysis. The fluoride adsorption as a function of pH, initial fluoride concentration, EGANaCl dose, temperature, co-ions and cycles of regeneration was studied using batch methods. Among the kinetic models, the pseudo – second – order model was superior to others and among the adsorption isotherms, Langmuir model fits well as compared to that of Freundlich model based on the regression coefficient values. Determination of thermodynamic parameters such as ΔH and ΔG respectively revealed the nature of endothermic and temperature – driven nature of the fluoride sorption process. The maximum adsorption capacity of EGANaCl was found to be 16.33 mg g−1 at 27 °C and a maximum fluoride removal occurred at pH 6.55. The spent adsorbent showed the defluoridation efficiency of 95.53% up to fifth regeneration with diluted NaOH. Factorial design matrix and analysis of variance using JMP model have also been extensively discussed in this paper.  相似文献   

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