► Activated carbon coated with magnetite nanoparticles was synthesized from biomass. ► Nano magnetization achieved in a single step process and well characterized. ► Adsorbent showed better ...superparamagnetism compared to reported elsewhere. ► New nano magnetite adsorbent effectively removed toxic hexavalent chromium. ► Continuous column reactor was designed and the parameters evaluated.
Activated carbon prepared from corn cob biomass, magnetized by magnetite nanoparticles (MCCAC) was used for the adsorption of hexavalent chromium from aqueous solution. The adsorbent was characterized by SEM, TEM, XRD, VSM, surface functionality and zero-point charge. The iron oxide nanoparticles were of 50nm sizes and the saturation magnetization value for the adsorbent is 48.43emu/g. Adsorption was maximum at pH 2. Isotherm data were modeled using Langmuir, Freundlich and Temkin isotherm. The prepared MCCAC had a heterogeneous surface. The maximum monolayer adsorption capacity was 57.37mg/g. Kinetic studies were carried out and the data fitted the pseudo second-order equation. The mechanism of the adsorption process was studied by incorporating the kinetic data with intraparticle diffusion model, Bangham equation and Boyd plot. The adsorption was by chemisorption and the external mass transfer was the rate-determining step. A micro column was designed and the basic column parameters were estimated.
In the present investigation an attempt was made to degrade organic pollutants in the textile effluent by homogeneous and heterogeneous Fenton systems. Experiments were carried out under the batch as ...well as under the continuous operating conditions. The effect of time, pH, H2O2 concentration, FeSO4.7H2O concentration and the mass of mesoporous activated carbon on the degradation of organics in the wastewater were critically examined. The kinetic constants and the thermodynamic parameters for the oxidation of organics in wastewater were determined. The quantitative removal of COD, BOD and TOC from the wastewater was evaluated. The degradation of organics in textile wastewater was confirmed through FT-IR, UV–Visible spectroscopy, and cyclic voltammetry.
Schematic flow diagram for integrated homogenous and heterogeneous Fenton oxidation of textile wastewater. Display omitted
► Mesoporous activated carbon was used as a heterogeneous catalyst in this study. ► COD was removed excess in this study over homogeneous Fenton oxidation by 30%. ► The mesoporous activated carbon enhances the rate of the oxidation reaction. ► This process involves minimum sludge production and low electrical energy input. ► The mesoporous activated carbon was active even after 18 cycles in this study.
Growth factors are essential in cellular signaling for migration, proliferation, differentiation and maturation. Sustainable delivery of therapeutic as well as functional proteins is largely required ...in the pharmacological and regenerative medicine. Here we have prepared chitosan nanoparticles (CNP) and incorporated growth factors such as epidermal growth factor (EGF) and fibroblast growth factor (FGF), either individually or in combination, which could ultimately be impregnated into engineered tissue construct. CNP was characterized by Fourier transform infrared (FTIR) spectroscopy, Zeta sizer and high resolution transmission electron microscope (HRTEM). The particles were in the size range of 50–100
nm with round and flat shape. The release kinetics of both EGF and FGF incorporated CNP showed the release of growth factors in a sustained manner. Growth factors incorporated nanoparticles did not show any toxicity against fibroblasts up to 4
mg/ml culture medium. Increased proliferation of fibroblasts
in vitro evidenced the delivery of growth factors from CNP for cellular signaling. Western blotting results also revealed the poor inflammatory response showing less expression of proinflammatory cytokines such as IL-6 and TNFα in the macrophage cell line J774 A-1.
In the present study,
Juglans regia
shells were used to prepare activated carbon by acid treatment method.
J
.
regia
shell-based activated carbon was used for the adsorption of two synthetic dyes ...namely, a basic dye malachite green and an acid dye amido black 10B. The prepared adsorbent was crushed and sieved to three different mesh sizes 100, 600 and 1,000 μm. The adsorbent was characterized by scanning electron microscopy, surface acidity and zero-point charge. Batch experiments were carried out by varying the parameters like initial aqueous phase pH, adsorbent dosage and initial dye concentration. The equilibrium data were tested with Langmuir, Freundlich, Redlich–Peterson and Sips isotherm at three different temperatures 293, 300 and 313 K and it was found that the Freundlich isotherm best fitted the adsorption of both the dyes. Kinetic data were tested with pseudo first-order model and pseudo second-order model. The mechanism for the adsorption of both the dyes onto the adsorbent was studied by fitting the kinetic data with intraparticle diffusion model and Boyd plot. External mass transfer was found to be the rate-determining step. Based on the ionic nature of the adsorbates, the extent of film diffusion and intraparticle diffusion varied; both being system specific. Thermodynamic parameters were also calculated. Finally, the process parameters of each adsorption system were compared to develop the understanding of the best suitable system.
•TiO2 NPs cytotoxicity at low exposure levels (≤1μg/mL) to freshwater algae.•ROS generation, NP adsorption and internalization contributors to toxicity.•Observational evidence of genotoxicity by ...nanoparticles in an algal cell.•Reduced bioavailability thus detoxification of NPs by microalgae.•Possible role of EPS in detoxification.
In the current study, two aspects concerning (i) the cytotoxicity potential of TiO2 nanoparticles (NPs) toward freshwater algal isolate Scenedesmus obliquus and (ii) the potential detoxification of NPs by the microalgae were assessed under light (UV-illumination) and dark conditions at low exposure levels (≤1μg/mL), using sterile freshwater as the test medium. The statistically significant reduction in cell viability, increase in reactive oxygen species production and membrane permeability (light vs. dark) suggested photo-induced toxicity of TiO2 NPs. The electron micrographs demonstrated adsorption of the NPs onto the cell surface and substantiated their internalization/uptake. The fluorescence micrographs and the confocal laser scanning (CLSM) images suggested the absence of a definite/intact nucleus in the light treated cells pointing toward the probable genotoxic effects of NPs. In a separate three cycle experiment, a continuous decrease in the cytotoxicity was observed, whereas, at the end of each cycle only fresh algae were added to the supernatant containing NPs from the previous cycle. The decreasing concentrations of the NPs in the subsequent cycles owing to agglomeration–sedimentation processes exacerbated by the algal interactions played a crucial role in the detoxification. In addition, the exo-polymeric substances produced by the cells could have rendered the available NPs less reactive, thereby, enhancing the detoxification effects.
Monocyclic and bicyclic oxazolidines were offered at three different junctures of chrome tanning process viz. prior to BCS offer, along with BCS and after basification. It was found that oxazolidine ...when offered after basification brought about better chromium uptake and reduction of chromium load in the wastewater. Offer of oxazolidine was also varied. Increase in offer of oxazolidine from 0.25% to 1% was found to enhance the chromium uptake and decrease the chromium load in wastewater. But the increase in uptake was not proportionate to the increase in oxazolidine offer more than 0.75%. Offer of 1% Zoldine ZA 78 (monocyclic oxazolidine) and Zoldine ZE (bicyclic oxazolidine) after basification brought about 63.4% and 73.1% enhancement in chrome content in leather compared to control where oxazolidine was not offered. The tone of the wetblue was found to be altered moderately. However this did not call for any process adjustments in wet-finishing. The oxazolidine treated leathers were found to be immensely fuller and tighter. It was found experimentally that offer of 1% of oxazolidine facilitated reduction in the offer of syntans administered for filling and grain tightening by around 46%. Oxazolidine could bring about significant reduction in cost of chemicals apart from resulting environmental benefits due to enhancement of chromium uptake during tanning.
The present study emphasizes the influence of non-covalent interactions on the mechanical and thermal properties of the scaffolds of chitosan/collagen origin. Malonic acid (MA), a bifuncitonal diacid ...was chosen to offer non-covalent cross-linking. Three dimensional scaffolds was prepared using chitosan at 1.0% (w/v) and MA at 0.2% (w/v), similarly collagen 0.5% (w/v) and MA 0.2% (w/v) and characterized. Results on FT-IR, TGA, DSC, SEM and mechanical properties (tensile strength, stiffness, Young’s modulus, etc.) assessment demonstrated the existence of non-covalent interaction between MA and chitosan/collagen, which offered flexibility and high strength to the scaffolds suitable for tissue engineering research. Studies using NIH 3T3 fibroblast cells suggested biocompatibility nature of the scaffolds. Docking simulation study further supports the intermolecular hydrogen bonding interactions between MA and chitosan/collagen.
Negative longitudinal magnetoresistance (NLMR) is shown to occur in topological materials in the extreme quantum limit, when a magnetic field is applied parallel to the excitation current. We perform ...pulsed and dc field measurements on Pb_{1-x}Sn_{x}Se epilayers where the topological state can be chemically tuned. The NLMR is observed in the topological state, but is suppressed and becomes positive when the system becomes trivial. In a topological material, the lowest N=0 conduction Landau level disperses down in energy as a function of increasing magnetic field, while the N=0 valence Landau level disperses upwards. This anomalous behavior is shown to be responsible for the observed NLMR. Our work provides an explanation of the outstanding question of NLMR in topological insulators and establishes this effect as a possible hallmark of bulk conduction in topological matter.
Mixed aquo-organic solvents are used in chemical, industrial, and pharmaceutical processes along with amphiphilic materials. Their fundamental studies with reference to bulk and interfacial phenomena ...are thus considered to be important, but such detailed studies are limited. In this work, the interfacial adsorption of sodium dodecylsulfate (SDS, C12H25SO4 –Na+) in dioxane–water (Dn–W) and methanol–water (Ml–W) media in extensive mixing ratios along with its bulk behavior have been investigated. The solvent-composition-dependent properties have been identified, and their quantifications have been attempted. The SDS micellization has been assessed in terms of different solvent parameters, and the possible formation of an ion pair and triple ion of the colloidal electrolyte, C12H25SO4 –Na+ in the Dn–W medium has been correlated and quantified. In the Ml–W medium at a high volume percent of Ml, the SDS amphiphile formed special associated species instead of ion association. The formation of self-assembly and the energetics of SDS in the mixed solvent media have been determined and assessed using conductometry, calorimetry, tensiometry, viscometry, NMR, and DLS methods. The detailed study undertaken herein with respect to the behavior of SDS in the mixed aquo-organic solvent media (Dn–W and Ml–W) is a new kind of endeavor.
The purpose of the present study was to elucidate the effects of feeding flaxseed meal (FSM) and turmeric rhizome powder (TRP) supplementation on tissue lipid profile, lipid metabolism, health ...indices, oxidative stability, and physical properties of broiler chicken meat. The 100 g FSM along with 10.0 g TRP supplementation significantly increased the ω-3 PUFA, particularly ALA, EPA, DPA, and DHA of broiler chicken meat due to the corresponding increase ∆9 and Δ5 + Δ6 desaturase activities. The increased activities of the desaturases resulted in significantly better health indices of the broiler chicken meat. The feeding of 100 g FSM along with 10.0 g TRP supplementation reduced the atherogenic and thrombogenic indices of broiler chicken meat. The 100 g FSM feeding reduced the oxidative stability, water holding capacity, extract release volume of broiler chicken meat and increased drip loss, whereas, 10.0 g TRP supplementation reversed these negative effects of FSM.
•Flaxseed and turmeric increase ω-3 PUFA, particularly ALA, EPA, DPA, and DHA, of chicken meat•The increased ∆9 and Δ5 + Δ6 desaturase activities result in better health indices of the chicken meat•Flaxseed and turmeric reduce atherogenic and thrombogenic indices of chicken meat•Flaxseed deteriorates oxidative stability and physical properties of meat and turmeric improves them
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