Sorption of indigo carmine by a Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge

Indigo carmine removal from aqueous solution has been evaluated using Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge treated with HCl (CM). The adsorbents were characterized by scanning electron microscopy, BET surface area and X-ray diffraction. Sorption kinetics and isotherms were determined and the adsorption behaviors analyzed. Kinetic pseudo-second order and Langmuir–Freundlich models were successfully applied to the experimental results obtained with the Fe-zeolitic material, while kinetic first order and Langmuir–Freundlich models were applied to the results from the carbonaceous materials. This indicates mechanisms of chemisorption and physic sorption, respectively, on the heterogeneous materials. The results indicate that the carbonaceous material from the pyrolysis of sewage sludge (sorption capacity 92.83 mg/g) is a better adsorbent of indigo carmine than the zeolitic material (sorption capacity 32.83 mg/g).     

Photocatalytic degradation of indigo carmine in aqueous solution by TiO2-coated non-woven fibres

The photocatalytic degradation of indigo carmine has been investigated in aqueous solutions using TiO2 coated non-woven fibres as photocatalyst. The experiments were carried out to investigate the factors influencing the photocatalytic degradation, such as the previous adsorption in the dark, initial concentration of dye solution, temperature, and pH. The experimental results show that adsorption is an important parameter controlling the apparent kinetic constant of the degradation. The photocatalytic degradation rate was favoured by a high concentration of solution in respect to Langmuir-Hinshelwood model. The degradation rate was pH and temperature dependent with a high degradation rate at high temperature.     

Batch and bulk removal of hazardous dye, indigo carmine from wastewater through adsorption

An inexpensive adsorption method has been developed for the removal of indigo carmine, a highly toxic indigoid class of dye from wastewater. Waste materials--bottom ash, a power plant waste and de-oiled soya, an agricultural waste--have been used as adsorbents. Attempts have been made through batch and bulk removal of the dye and both the adsorbents have been found to exhibit good efficiency to adsorb indigo carmine. Under batch technique effect of temperature, pH, concentration, dosage of adsorbents, sieve size of adsorbents, etc. have been observed. The dye uptake on to both the adsorbents is found to validate Langmuir and Freundlich adsorption isotherms models. Different thermodynamic parameters, like Gibb's free energy, enthalpy and entropy of the on-going adsorption process have also been evaluated. Batch technique has also been employed for the kinetic measurements and the adsorption follows a first order rate kinetics for both the adsorbents. The kinetic investigations also reveal for both the adsorbents film diffusion and particle diffusion mechanisms are operative in the lower and higher concentration ranges, respectively. Under the bulk removal, indigo carmine has been adsorbed through the column beds of bottom ash and de-oiled soya and more than 90% of the dye material has been recovered by eluting dilute NaOH solution through exhausted columns.     

Removal of indigo carmine dye from water to Mg-Al-CO(3)-calcined layered double hydroxides

Layered double hydroxides (LDHs) calcined, denoted as CLDHs, have been shown to recover their original layered structure in the presence of appropriate anions. In the light of this so-called "memory effect", the removal of indigo carmine (IC), an anionic dye, from aqueous solution by calcined Mg-Al-CO(3) LDHs was investigated in batch mode. We looked at the influence of pH values, dye-adsorbent contact time, initial dye concentration and various temperatures of heating of LDHs on the decolorization rate of IC. The adsorption isotherms, described by Freundlich model are L-type. The characterization of the solids CLDHs, both fresh and after removal of IC, by X-ray diffraction and infrared spectroscopy shows that the IC adsorption on CLDHs is enhanced by reconstruction of a matrix hydrotalcite intercaled by the dye, and the intercalation of the organic ion was clearly evidenced by the net increase in the basal spacing from 0.76 nm for [Mg-Al-CO(3)] to 2.13 nm for the organic derivative.     

Photocatalytic degradation of indigo carmine dye using TiO<Subscript>2</Subscript> impregnated activated carbon

The photocatalytic degradation of indigo carmine dye was studied using hydrothermally prepared TiO₂ impregnated activated carbon (TiO₂: AC). A comparison between the degradation of the indigo carmine dye using commercial TiO₂ and TiO₂: AC revealed the efficiency of the title compound. The degradation reaction was optimized with respect to the dye concentration and catalyst amount. The reduction in the chemical oxygen demand (COD) revealed the mineralization of dye along with colour removal. The active compound like TiO₂ was impregnated onto the activated carbon surface under mild hydrothermal conditions (<250°C, P ∼ 40 bars). The impregnated activated carbon samples were characterized using powder X-ray diffraction (XRD) and scanning electron microscope (SEM).     

Interaction of lipid vesicle with silver nanoparticle-serum albumin protein corona

The physical interaction between a lipid vesicle and a silver nanoparticle (AgNP)-human serum albumin (HSA) protein "corona" has been examined. Specifically, the binding of AgNPs and HSA was analyzed by spectrophotometry, and the induced conformational changes of the HSA were inferred from circular dichroism spectroscopy. The fluidity of the vesicle, a model system for mimicking cell membrane, was found to increase with the increased exposure to AgNP-HSA corona, though less pronounced compared to that induced by AgNPs alone. This study offers additional information for understanding the role of physical forces in nanoparticle-cell interaction and has implications for nanomedicine and nanotoxicology.     

The removal of the indigo carmine dye from aqueous solutions using cross-linked chitosan: evaluation of adsorption thermodynamics using a full factorial design

A 2(3) factorial design was employed to evaluate the quantitative removal of the indigo carmine (IC) dye from aqueous solutions on glutaraldehyde cross-linked chitosan. The variables were chitosan masses of 100 and 300 mg, IC concentrations of 2.0 and 5.0 x 10(-5) mol L(-1) and temperatures of 25 and 35 degrees C. The quantitative and energetic adsorption parameters were analyzed statistically using modeling with bilinear equations. The results indicated that increasing the chitosan mass from 100 to 300 mg decreases the IC adsorption/mass ratio (mol g(-1)) whereas a temperature increase of 25-35 degrees C increases it. The principal effect of the IC concentration did not show statistical significance. The factorial experiments demonstrate the existence of a significant antagonistic interaction effect between the chitosan mass and temperature. The adsorption thermodynamic parameters, namely Delta(ads)H, Delta(ads)G, and Delta(ads)S, were determined for all the factorial design results. Endothermic values were found in relation to the Delta(ads)H. The positive Delta(ads)S values indicate that entropy is a driving force for adsorption. The Delta(ads)G values are also significantly affected by important antagonistic and synergistic effects involving all principal and interactive factors. It is concluded that the thermodynamical spontaneity of the IC adsorption parameters are greatly influenced by the interactive factors and not by the temperature changes alone.     

Nuclear spin relaxation rates by NMR on oriented nuclei:60CoCo

We have applied a general multipole relaxation theory recently developed by one of the authors to the interpretation of the nuclear spin-lattice relaxation times of⁶⁰Co in Co at nuclear orientation temperatures. In order to do this a numberical method for calculating the relaxation factors for high spins at low temperatures was developed. The initial conditions and experimental details are discussed.     

阳离子表面活性剂CTAB与聚乙烯醇间相互作用的NMR分析

用1H谱,自旋-晶格弛豫时间（t1）和自旋-自旋弛豫时间（t2）,gCOSY谱及二维核Overhause增强谱（2D NOESY）技术,研究了阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）与水溶性聚合物聚乙烯醇（PVA）的相互作用。结果表明,当溶液中有CTAB存在时,PVA分子结构中的-CH质子的t1减小了0.8s,...     

Interaction of malachite green with bovine serum albumin: determination of the binding mechanism and binding site by spectroscopic methods

The interaction between malachite green (MG) and bovine serum albumin (BSA) under simulative physiological conditions was investigated by the methods of fluorescence spectroscopy, UV-vis absorption and circular dichroism (CD) spectroscopy. Fluorescence data showed that the fluorescence quenching of BSA by MG was the result of the formation of the MG-BSA complex. According to the modified Stern-Volmer equation, the effective quenching constants (K(a)) between MG and BSA at four different temperatures were obtained to be 3.734 x 10(4), 3.264 x 10(4), 2.718 x 10(4), and 2.164 x 10(4)L mol(-1), respectively. The enthalpy change (Delta H) and entropy change (DeltaS) were calculated to be -27.25 kJ mol(-1) and -11.23 J mol(-1)K(-1), indicating that van der Waals force and hydrogen bonds were the dominant intermolecular force in stabilizing the complex. Site marker competitive experiments indicated that the binding of MG to BSA primarily took place in sub-domain IIA. The binding distance (r) between MG and the tryptophan residue of BSA was obtained to be 4.79 nm according to F?rster theory of non-radioactive energy transfer. The conformational investigation showed that the presence of MG decreased the alpha-helical content of BSA (from 62.6% to 55.6%) and induced the slight unfolding of the polypeptides of protein, which confirmed some micro-environmental and conformational changes of BSA molecules.     

Study of surface relaxation mechanism of liquid3He in porous glass by using SQUID NMR

Nuclear spin relaxation of liquid³He in porous glass has been studied. In addition to measurements of the longitudinal spin relaxation timeT ₁ by a usual pulsed SQUID NMR, measurements of the transverse spin relaxation timeT ₂ have been performed by using a newly developed SQUID NMR method to observe a spin echo signal. Temperature and frequency dependences ofT ₁ andT ₂ have been measured. A simple model is proposed which explains the main features of the experimental results.     

温度敏感葡聚糖凝胶的合成及其细胞相容性研究

合成了N-异丙基丙烯酰胺（NIPAAm）与葡聚糖的共聚水凝胶，利用红外光谱表征了单体和凝胶结构，研究了水凝胶在去离子水和细胞培养基中的温度响应性，并对凝胶进行了细胞培养和脱附研究．结果表明，共聚凝胶具有很好的温度敏感性和细胞相容性，可以通过控制温度变化，实现对细胞的无损伤脱附．     

Association of indigo with zeolites for improved color stabilization

The durability of an organic color and its resistance against external chemical agents and exposure to light can be significantly enhanced by hybridizing the natural dye with a mineral. In search for stable natural pigments, the present work focuses on the association of indigo blue with several zeolitic matrices (LTA zeolite, mordenite, MFI zeolite). The manufacturing of the hybrid pigment is tested under varying oxidizing conditions, using Raman and ultraviolet-visible (UV-Vis) spectrometric techniques. Blending indigo with MFI is shown to yield the most stable composite in all of our artificial indigo pigments. In the absence of defects and substituted cations such as aluminum in the framework of the MFI zeolite matrix, we show that matching the pore size with the dimensions of the guest indigo molecule is the key factor. The evidence for the high color stability of indigo@MFI opens a new path for modeling the stability of indigo in various alumino-silicate substrates such as in the historical Maya Blue pigment.     

Interaction of dissolved atoms and relaxation due to interstitial atoms in hcp metals

The literature data on the mechanism of internal friction maxima induced by O, N, and C in α-Ti, α-Zr, and α-Hf, are contradictory. They do not answer the question which kind of complexes induces relaxation: interstitial atoms or interstitial atoms with substitutional atoms. To clarify this question, modeling of the short-range order and atomic displacement fields around the solute atom clusters was carried out by the Monte-Carlo technique for typical Ti–O–Zr alloys. The energies of strain-induced (elastic) O–O and O–Zr interactions and displacement fields of host atoms around the solute atoms were calculated and used in modelling. The concentration dependence of relaxation strength due to diffusion under stress of oxygen atoms was evaluated using the values of local displacement around the solute atom complexes. It is shown that the developing short-range order cannot be described by the single O–O or O–Zr pair and the associated relaxation, as simple reorientation of any specific atomic pairs. It seems likely that in many cases the internal friction is caused by more complicated clusters constituted by interstitial and substitutional atoms.     

Interaction of stress relaxation aging behavior and microstructural evolution in Inconel 718 alloy with different initial stress status

Journal of Materials Science - The two-stage aging treatment with different initial loading stresses were carried out in the Inconel 718 alloy after solution annealing process to investigate the...     

A numerical study of non-equilibrium flows with different vibrational relaxation models

Comparative analysis of a widely used Landau–Teller formula for small deviations from thermal equilibrium and its generalized form, derived from the kinetic theory of gaseous, for an arbitrary deviation from the thermal equilibrium is performed by numerical simulation. Thermally non-equilibrium flows of carbon dioxide near a sharp-edged plate, pure nitrogen flows between two symmetrically located wedges, and the N₂/N mixture flow with vibrational relaxation and dissociation over a cone have been considered. A comparison has been performed with the available experimental data.     

Desalination of porous building materials by electrokinetics: an NMR study

This article presents the first non destructive measurements of salt ions transport through fired-clay brick during electrokinetic desalination using nuclear magnetic resonance technique. The effect of the strength of an applied electric field on the migration of salt ions is examined by varying the electrical potential gradients from 0.75–2 V cm^?1 across the specimens. The measurements show that for electrokinetic to exceed ion transport by diffusion a minimum level of applied voltage is necessary. Below this threshold salt transport by diffusion is dominant over electromigration. The effect of advection on the salt transport is studied by introducing a hydraulic gradient across the specimen. The results show that advection is a major transport process in the materials studied. To assess the relative magnitude of the various active transport processes during electrokinetic desalination, a scale analysis on the basis of dimensionless numbers is presented. The value of these numbers determines which transport mechanism will dominate the desalination process in a given sample length and time scale.     

Effect of pair-breaking on the superconducting fluctuation contribution to the NMR relaxation rate

We investigate the effect of pair-breaking on the contribution of s-wave order parameter fluctuations to the NMR relaxation rate for clean 2D superconductors. For Gaussian fluctuations we evaluate the Maki-Thomson diagram taking into account pairing breaking in both the fluctuation propagator and the Green's functions. The fluctuation peak in 1/T ₁ near T_c is strongly reduced by pair-breaking as is the case for the Hebel-Slichter peak.