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1.
The surface molecular imprinting technique has been proposed as a prospective strategy for template molecule recognition and separation by devising the recognition sites on the surface of imprinted materials. The purpose of this study was to establish a novel drug delivery system which was developed by surface molecular imprinting method using β-cyclodextrin (β-CD)-grafted chitosan (CS) (CS-g-β-CD) microspheres as matrix and sinomenine hydrochloride (SM) as the template molecule. By adjusting the amount of functional monomer and cross-linking agent, we got the more excellent adsorption of CS-g-β-CD molecularly imprinted polymers (MIPs-CS-g-β-CD). When the amount of functional monomer was 6 mmol and cross-linking agent was 20 mmol, the maximum binding capacity of MIPs and non-imprinted polymers (NIPs) was 55.9 mg/g and 37.2 mg/g, respectively. The results indicated that the recognition of SM with MIPs was superior to NIPs. The adsorption isotherms of MIPs-CS-g-β-CD indicated that the adsorption behavior fitted better to the Langmuir model, which showed that the adsorption process of polymer was monomolecular layer. In in vitro drug release studies, the accumulative release amount of MIPs-CS-g-β-CD was up to 78% within 24 h. MIPs exhibited an excellent controlled SM release profile without burst release and the mechanism of SM release was shown to conform to non-Fick diffusion. Therefore, MIPs-CS-g-β-CD were successfully applied to extraction of SM and used as the materials for drug delivery system.  相似文献   

2.
Methylene blue (MB) removal using eco-friendly, cost-effective, and freely available Urtica was investigated. The morphology of the adsorbent surface and the nature of the possible Urtica and MB interactions were examined using SEM analysis and the FTIR technique, respectively. Various factors affecting MB adsorption such as adsorption time, initial MB concentration, temperature, and solution pH were investigated. The adsorption process was analysed using different kinetic models and isotherms. The results showed that the MB adsorption kinetic follows a pseudo-second-order kinetic model and the isotherm data fit the Langmuir isotherm well. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were also evaluated, and the results indicated that the adsorption process is endothermic and spontaneous in nature. The MB adsorption capacity of Urtica was found to be as high as 101.01 mg g?1, higher than those of many other adsorbents studied in the literature. This superior adsorption capacity, along with the ready availability of Urtica, render this adsorbent potentially suitable for practical applications.  相似文献   

3.
A Cd(II)-imprinted thiocyanato-functionalized silica gel adsorbent with high adsorption capacity was prepared by surface imprinting technique combined with sol–gel process for the selective adsorption of Cd(II) ion in aqueous solution, and was characterized by Fourier-transform infrared spectroscopy, nitrogen gas sorption and thermogravimetric analysis. The influences of different conditions (such as the pH of solutions, the contact time and the initial concentrations of Cd(II) ions) on the adsorption capacity of Cd(II) were investigated. The optimum pH of adsorption was in the range of 4–8.5. The adsorption equilibrium could be reached in 20 min. The relatively selectivity coefficients of the imprinted silica were higher than those of the non-imprinted adsorbents. Ho’s pseudo-second-order model well described the kinetics of the adsorption reaction. The adsorption process of metals followed Redlich–Peterson isotherm model, and the experimental value of maximum adsorption capacity for Cd(II) was 72.8 mg·g?1. The positive value of ΔH o suggested endothermic nature of Cd(II) adsorption on the imprinted silica adsorbent. Increase in entropy of adsorption reaction was shown by the positive value of ΔS o and the negative value of ΔG o indicating that the adsorption was spontaneous in nature.  相似文献   

4.
A chloromethylated polystyrene-N-methyl thiourea chelating resin (DMTUR) was successfully prepared by the reaction of chloromethylated polystyrene beads (PS-Cl) with N-methyl thiourea (DMTU). The DMTUR exhibited a high selective adsorption toward Hg(II) in the mixture of different metal ions containing Cu(II), Hg(II), Cd(II), Pb(II), Cr(III) and Ni(II), and the adsorption capacity of Hg(II) approached a maximum with a value of 347 mg/g at pH = 4.0. Moreover, the batch kinetic study showed that the adsorption behavior of Hg(II) presented as a pseudo-second-order manner. And the adsorption isotherms fitted well with Langmuir model, and the maximum uptake of Hg(II) could reach to be 476 mg g?1 at 35 °C. The thermodynamics study ensured the adsorption process essentially as favorable and endothermic. Finally, an eluent of 4 M HNO3 solution could completely remove the adsorbed Hg(II) and the adsorption capacity allowed a high level at least five cycles. As aforementioned appealing properties, the DMTUR with simple technology, high adsorption capacity, significant selectivity and good regenerability may have a potential application in industrial scale as a treatment of enriched Hg(II) in wastewater.  相似文献   

5.
Shifts of chromatographic peak maxima and centres of gravity have been investigated for different amounts of propane injected on to a chromatographic column in ideal, non-linear chromatography. Specific retention volumes (V g (273), corrected to the standard temperature, 273.15 K), propane adsorption isotherms, and the first and second derivatives of the isotherms, (da/dp) T and (d2a/dp2) T , were determined for samples of active carbon and for different amounts of propane injected on column. Relationships between specific retention volume and the molar differential work of adsorption, A, were calculated on the basis of the propane isotherms and using the retention times of the peak maxima and the centres of gravity of the peaks. The equations obtained, ln V g (273)=f1(A) and(dW/dA) T, F c = f2(ln V g (273)), have been used to explain the relationships between (i) chromatographic peak profiles and (ii) the distribution function of pore volumes filled with propane and the molar differential work of adsorption at different column temperatures (303–318 K).  相似文献   

6.
In pursuit of improving performance of the methylene blue adsorption process, the potential of a novel 4A-zeolite/polyvinyl alcohol (PVA) membrane adsorbent was investigated. Adding 4A-zeolite particles to the PVA membrane adsorbent provided an effective structure for the adsorptive membrane in dye removal processes. Effect of zeolite content was also studied via synthesis of different mixed matrix membrane adsorbents (MMMAs) with 5, 10, 15, and 20 wt% 4A-zeolite content. Morphology of MMMAs was analyzed by scanning electron microscope and the intermolecular interactions were determined by Fourier transform infrared spectroscopy. X-ray diffraction was performed to determine the crystal structure of MMMAs. For the sake of finding optimum condition, the adsorption capacity was examined at various operating parameters, such as contact time, temperature, pH, and initial concentration. The maximum value of the adsorption capacity (q e) of 41.08 mg g?1 and the highest removal efficiency of 87.41 % were obtained by applying 20 wt% loading of 4A-zeolite. The experimental data were fitted well with the Freundlich adsorption isotherm model (R 2 = 0.9917) compared with the Langmuir (R 2 = 0.9489) and the Tempkin (R 2 = 0.8886) adsorption isotherm models, and the adsorption kinetic data verified the best fitting with the pseudo-second-order model (R 2 = 0.9999). The estimated data for Gibb’s free energy (ΔG°) showed that the adsorption process is spontaneous at lower temperature values and non-spontaneous at higher temperature values. Other evaluated thermodynamic parameters such as changing in enthalpy (ΔH°) and entropy (ΔS°) revealed that the adsorption process is exothermic with an increase in orderliness at the solid/solution interface.  相似文献   

7.
In this study,the maleic anhydride(MAH)and styrene(St)dual monomers grafted polypropylene(PP)and poly[styrene-b-(ethylene-co-butylene)-b-styrene](SEBS),i.e.PP-g-(MAH-co-St)and SEBS-g-(MAH-co-St)are prepared as multi-phase compatibilizers and used to compatibilize the PA6/PS/PP/SEBS(70/10/10/10)model quaternary blends.Both PS and SEBS are encapsulated by the hard shell of PP-g-(MAH-co-St)in the dispersed domains(about 2μm)of the PA6/PS/PP-g-(MAH-co-St)/SEBS(70/10/10/10)quaternary blend.In contrast,inside the dispersed domains(about 1μm)of the PA6/PS/PP/SEBS-g-(MAH-co-St)(70/10/10/10)quaternary blend,the soft SEBS-g-(MAH-co-St)encapsulates both the hard PS and PP phases and separates them.With increasing the content of the compatibilizers equally,the morphology of the PA6/PS/(PP+PP-g-(MAH-co-St))/(SEBS+SEBS-g-(MAH-co-St))(70/10/10/10)quaternary blends evolves from the soft(SEBS+SEBS-g-(MAH-co-St))encapsulating PS and partially encapsulating PP(about 1μm),then to PS exclusively encapsulated by the soft SEBS-g-(MAH-co-St)and then separated by PP-g-(MAH-co-St)inside the smaller domains(about 0.6μm).This morphology evolution has been well predicted by spreading coefficients and explained by the reaction between the matrix PA6 and the compatibilizers.The quaternary blends compatibilized by more compatibilizers exhibit stronger hierarchical interfacial adhesions and smaller dispersed domain,which results in the further improved mechanical properties.Compared to the uncompatibilized blend,the blend with both 10 wt%PP-g-(MAH-co-St)and 10 wt%SEBS-g-(MAH-co-St)has the best mechanical properties with the stress at break,strain at break and impact failure energy improved significantly by 97%,71%and 261%,respectively.There is a strong correlation between the structure and property in the blends.  相似文献   

8.
Sodium carboxymethyl cellulose (SCMC) with different degrees of substitution (DS) possesses structural characteristics and physicochemical properties that are important in broad areas of industrial applications. This reported work investigated the structural characteristics, including the effective length (L ef), the radius of gyration (R g), and the hydrodynamic radius (R H), and the physicochemical properties, including intrinsic viscosity ([η]) and salt tolerance, of SCMC with a DS more than 1.0 in NaCl solution using molecular dynamics (MD) simulations. In the MD simulations, the DS of SCMC varied from 1.2 to 2.8, and the NaCl concentration varied from 0 to 1.4 mol/L. MD simulation results showed that with the increment of NaCl concentration, the L ef (or R g or R H) of SCMC decreased; with the increment of the DS, the L ef of SCMC increased. Also, the variation tendency of [η] in the NaCl solution was consistent with its L ef (or R g or R H). It was noted that the salt tolerance (represented by D) of SCMC increased as the DS increased. In addition, the sharp variation of the D value of SCMC occurred in the range of DS of 1.6 to 2.0, which agreed with the reported experimental results. Radial distribution function analyses showed that the Na+ cations had a stronger interaction with the carboxyl groups in SCMC with lower DS when it was present in a salt solution of higher concentration, which also reasonably explained the variation of L ef, R g, R H, [η], and D of SCMC in NaCl solution.  相似文献   

9.
10.
The present study investigates the adsorption capability of raw and biochar forms of Chrysanthemum indicum flowers biomass to remove cobalt ions from aqueous solution in a fixed-bed column. Column adsorption experiments were conducted by varying the bed height (1.0, 2.0, 3.0 cm), flow rate (1.0, 2.5, 5.0 mL min?1) and initial cobalt ion concentration (25, 50, 75 mg L?1) to obtain the experimental breakthrough curves. The adsorption capacity of the raw and biochar forms of C. indicum flowers were found to be 14.84 and 28.34 mg g?1, respectively, for an initial ion concentration of 50 mg L?1 at 1.0 cm bed height and 1.0 mL min?1 flow rate for Co (II) ion adsorption. Adam–Bohart, Thomas and Yoon–Nelson models were applied to the experimental column data to analyze the column performance. The Thomas model was found to best represent the column data with the predicted and experimental uptake capacity values correlating well and with higher R 2 values for all the varying process parameters. Desorption studies revealed the suitability of the adsorbents for repeated use up to four adsorption–desorption cycles without significant loss in its efficiency. It can thus be inferred from the fixed-bed column studies that C. indicum flowers can suitably be used as an effective adsorbent for Co (II) ion removal from aqueous solution on a higher scale.  相似文献   

11.
Two series of new amide derivatives containing 2,6-diisobornylphenol moiety were synthesized based on 3,5-diisobornyl-4-hydroxybenzoic acid and 4-butylaminomethyl-2,6-diisobornylphenol. Toxicity, membrane-protective (MP) and antioxidant (AO) activity of the obtained compounds were evaluated using red blood cells of laboratory mice as the test object. The tests demonstrated the absence of hemolytic activity for all the synthesized derivatives and the presence of high MP and AO activity under conditions of acute H2O2-induced oxidative stress for (3,5-diisobornyl-4-hydroxyphenyl)(morpholino)methanone and N-n-butyl-N-(3,5-diisobornyl-4-hydroxybenzyl)acetamide. A comparison of the data of the newly obtained compounds and those of described earlier 2,6-diisobornylphenol derivatives with N- and O-containing fragments at position 4 (alkoxymethyl, carboxy, and aminomethyl derivatives) led to a conclusion that the most promising for further studies of pharmacological activity are compounds containing methoxycarbonyl, methoxymethyl, ethoxymethyl, morpholinomethyl, di-n-butylaminomethyl, (azepan-1-yl)methyl, or N-acetyl-N-alkylaminomethyl function, which provide low toxicity and high MP and AO activity.  相似文献   

12.
In this study, regular-shaped magnetic-activated carbon nanocomposite (m-Fe3O4@ACCs) was synthesized and characterized with X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and the vibrating sample magnetometer (VSM) and was used as adsorbents for the removal of nitrotoluene compounds (NTCs) from water and industrial wastewater. The effective parameters on adsorption process, such as solution pH, shaking speed, contact time, and adsorbent dosage were optimized and the optimum amounts were 7 300 rpm, 10 min, and 1.2 g L–1, respectively. The contact time and adsorbent dosage are dependent parameters and hence were studied simultaneously. The results showed no significant loss in the adsorption capacity, and the adsorption efficiency of m-Fe3O4@ACCs could still be 90% in the 9th cycle. The equilibrium adsorption isotherm followed the Langmuir isotherm model describes the monolayer adsorption of NTCs on m-Fe3O4@ACCs, and the maximum adsorption capacities (qm) for 2-nitrotolouene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, and 3,4-dinitrotoluene were found to be 144.93, 142.86, 166.67, and 153.85 mg g?l, respectively. The proposed process was successfully applied for the removal of NTCs from tap water and nitration process wastewater.  相似文献   

13.
The present investigation aimed to study and compare the efficiency of non-viable fungal isolates to remove divalent lead (Pb(II)) from aqueous streams. The selected fungal isolates showed identity with Aspergillus caespitosus, Aureobasidium sp. RBSS-303 and Aspergillus flavus HF5 as confirmed using gene sequencing of ITS regions of the ribosomal DNA (rDNA). The obtained equilibrium data for Pb(II) biosorption of A. caespitosus fitted better to Langmuir isotherm with maximum sorption capacity of 351.0 mg/g and A. sp. RBSS-303 and A. flavus HF5 showed good fit to Freundlich isotherm with maximum sorption capacity of 271.5 and 346.3 mg/g respectively. The values of thermodynamic factors ascertained the nature of adsorption process is endothermic with A. caespitosus and A. flavus HF5 but exothermic with A. sp. RBSS-303. The experimental data for Pb(II) biosorption fits very well to pseudo second order kinetic model. With HCl the maximum 85.5, 75.3, 73.7% recovery of Pb(II) was obtained from A. caespitosus, A. sp. RBSS-303 and A. flavus HF5, respectively. The observed percentage loss in sorption capacity of Pb(II) was 3.9% by A. flavus HF5, 12.2% by A. caespitosus and 26.6% by A. sp. RBSS-303 after five cyclic studies of sorption and desorption. Results from the study confirmed the efficiency order of A. caespitosus > A. flavus HF5 > A. sp. RBSS-303 to remove and recover Pb(II) from aqueous solution. Finally, the fungal biosorbents can be used as soil conditioning agent after compositing into valuables fungal protein.  相似文献   

14.
The physicochemical (acidic-basic, adsorption, and electrophysical) surface properties of binary semiconductor analogs of CdBVI (CdTe, CdSe, and CdS), and (CdTe)x(CdSe)1–x, and (CdTe)x(CdS)1–x solid substitution solutions were studied using modern methods and equipment. The nature of the active centers and the mechanisms of acidic-basic, adsorption (involving СО), and electronic interactions, interrelated tendencies in variation of the surface properties under study, and their correlations with the known bulk physicochemical properties were elucidated; the property–composition diagrams were constructed, which were used to reveal the most active adsorbents suggested for use as materials for СО (carbon monoxide) microimpurity sensors.  相似文献   

15.
5A zeolites were facilely synthesized from attapulgite clay and sodium aluminate precursors. The optimum synthesis condition for 4A zeolite (Na-form) were H2O/attapulgite ratio of 40:1 volume/mass, NaOH/attapulgite mass ratio of 2.35:1, the crystallization time was 4 h at 80–85 °C. The 4A zeolite was converted to related 5A zeolite (Ca-form) through ionic exchanges using calcium chloride solution with the Si/Al mole ratio of 1.3. SEM images demonstrated that as-synthesized 5A zeolites are ordered cubic crystals, average crystals length dimension is 1–2 μm. And the zeolites product had a specific surface area of 482 m2 g?1 and total pore volume of 0.274 cm3 g?1. The static adsorption experiments showed that the equilibrium adsorption capacities of n-decane and n-pentadecane on produced 5A zeolite were 0.253 and 0.510 g g?1, respectively. And the adsorption equilibrium time of n-decane and n-pentadecane on 5A zeolite were 45 and 60 min, respectively. The experimental adsorption data of n-decane and n-pentadecane on three zeolites could be properly fitted by the Langmuir–Freundlich isotherm model.  相似文献   

16.
9-Diazofluoren adds in Et2O at 20°C to methyltetrolate in keeping with Auwers rule and nonregioselectively adds to methyl-3-phenylpropiolate with the formation of spirocyclic 3H-pyrazoles. The methyltetrolate adduct at boiling in toluene converts into methyl 3a-methyl-3aH-dibenzo[e,g]indazole-3-carboxylate, at 190°C in benzene, into methyl 3-methyl-2H-dibenzo[e,g]indazole-2-carboxylate, and at 160°C in methanol, into 3-methyl-2H-dibenzo[e,g]indazole. Auwers adduct of methyl 3-phenylpropiolate at boiling in benzene gives cyclopropene derivative and at boiling in methanol isomerizes into methyl 3a-phenyl-3aHdibenzo[e,g]indazole-3-carboxylate. Anti-Auwers adduct at boiling in benzene isomerizes into methyl 2-phenylpyrazolo[1,5-f]phenanthridine-3-carboxylate.  相似文献   

17.
A couple of novel electrochromic materials poly(2,3,4,5-tetrakis(2,3-hydrothieno[3,4-b]dixin-5-yl)-1-methyl-1H-pyrrole) (P(t-EDOT-mPy)) and poly(5,5′,5′′,5′′′-(thiophene-2,3,4,5-tetrayl)tetrakis(2,3-dihydrothieno[3,4-b][1,4]dioxine)) (P(t-EDOT-Th)) are electrodeposited via multi-position polymerization of their tetra-EDOT substituted monomers t-EDOT-mPy and t-EDOT-Th, respectively. Compared with the linear 2D structured poly(thiophene) (E g=2.2 eV) and poly(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophene) (E g=1.7 eV), P(t-EDOT-Th) (E g=1.62 eV) has the lowest band gap. Hence, we speculate that the band gaps of the two polymers, having 3D structures, are decreased in contrast to non-substituted polymers or bi-EDOT substituted polymers, thiophene and 1-methyl-1H-pyrrole. The results indicated that P(t-EDOT-Th) thin films are more stable and show higher transmittance amid two polymers, which may find their utilization in organic optoelectronics.  相似文献   

18.
Glycosylation of 3β,12β-dihydroxy-20R,25-epoxydammarane (panaxadiol) (1) under Koenigs–Knorr, Helferich, and ortho-ester reaction conditions was studied. Condensation of panaxadiol and 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosylbromide (2) in the presence of silver oxide and 4-Å molecular sieves in dichloroethane gave a mixture of acetylated panaxadiol 3- and 12-O-β-D-glucopyranosides (3:1 ratio). Reaction of diol 1 and D-glucose tert-butylorthoacetate (3) in the presence of 2,4,6-collidinium perchlorate in chlorobenzene resulted in regioselective formation of panaxadiol 12-O-β-D-glucopyranoside tetraacetate. Reaction of equimolar amounts of 1 and glycosyl donor 2 in the presence of Hg(II) cyanide in nitromethane at 90°C was accompanied by opening of the tetrahydropyran ring and gave 3β,12β,25-trihydroxydammar20(22)E-ene 12-O-β-D-glucopyranoside tetraacetate. Panaxadiol 3- and 12-O-β-D-glucopyranosides and 3β,12β,25-trihydroxydammar-20(22)E-ene 12-O-β-D-glucopyranoside tetraacetate were synthesized for the first time.  相似文献   

19.
The reactions of Mn2+ ion with 4-nitrobenzene-1,2-bicarboxylic acid in the presence of bipyridyl-type coligands gave two new manganese(II) coordination polymers, [Mn2(Nbdc)2(Bipyp)(H2O)4] n (I) and [Mn2(Nbdc)2(Bipye)(H2O)4] n (II) (H2Nbdc = 4-nitrobenzene-1,2-bicarboxylic acid, Bipyp = 1,3-bi(4-pyridyl)propane, and Bipye = 1,2-bi(4-pyridyl)ethane). Both two complexes contain uniform carboxyl-bridged manganese chains with the composition of [Mn2(Nbdc)2(H2O)4] n , which are interlinked by interchain Bipyp/Bipye spacers to afford two closely-related layers (CIF files CCDC nos. 1008182 (I) and 1008183 (II)). Magnetic studies for two compounds show the presence of similar antiferromagnetic couplings between the adjacent Mn2+ ions through the carboxyl bridges, the best fittings to the experimental magnetic susceptibilities gave J =–0.20 cm–1 and g = 1.96 for I, and J =–0.24 cm–1 and g = 1.98 for II. Similar magnetic parameters and thermal behaviors further verify that two compounds possess closely-related structures.  相似文献   

20.
The Pseudomonas monteilii. YL-1 was cultured from deep sea sediment to remove uranium from aqueous solution. Different influence factors on uranium adsorption efficiency were investigated. The kinetic model of Pseudomonas monteilii could be described by the pseudo-second-order kinetic model, and the Freundlich isotherm model could fit the experiment data well, indicating that the adsorption was multilayer adsorption. The adsorption was spontaneous and endothermic reaction by thermodynamic analysis. The functional groups of Pseudomonas monteilii such as hydroxy, carboxyl, amino and amide may act with UO22+ by chemisorption or strong complexation in the process of uranium adsorption.  相似文献   

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