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Abstract Photocatalytic reduction of CO 2 has gained interest due to dual benefits of reduction of global warming and production of synthetic fuels. In this work, we report photochemical reduction of CO 2 using CdS and CdS/Mn 2 O 3 nanocomposites as photocatalyst supported on porous anodic alumnia (PAA) support. Incomplete anodization of an aluminum film substrate leaves a thin layer of aluminum in the middle that improves mechanical integrity and retain electrical conductivity of the support. The rod shaped crystals of CdS, grown on the support's pore surface form a crumpled sheet like structure that helps in trapping of light energy incident on the catalyst surface. The photocatalytic reduction of CO 2 was performed under the direct sunlight, using reflectors like flat mirrors, compound parabola, and concentrating Fresnel lens to direct solar radiation onto the catalytic surface. The combination of Fresnel lens as concentrator and CdS/Mn 2 O 3 nanocomposite as the catalyst gave exceptional increase in the photocatalytic activity when compared with CdS alone, with a peak formation rate of 52.2 μmol/g.cat/hr of C 2 H 5 OH, 1392.3 μmol/g.cat/hr of HCOOH and H 2 production at the rate of 2766 μmol/g.cat/hr. Graphical abstract Image 1008 Highlights • Incomplete anodization of Al substrate, during fabrication of PAA leaves a thin layer of Al in the middle, which improves mechanical integrity and electrical conductivity of the support. • A hybrid method of CdS deposition was adopted on PAA/Al/PAA. Mn 2 O 3 was later deposited on CdS surface. • The photocatalytic reduction of CO 2 was performed under the direct sunlight, using flat mirror, compound parabola reflectors, and Fresnel lens to focus solar radiation on the catalytic surface. • CdS/Mn 2 O 3 nanocomposite as catalyst and Fresnel lens as concentrator has shown exceptional increase in photocatalytic activity. [ABSTRACT FROM AUTHOR]

Abstract Pyrolysis of biomass converts it to bio-oil, which contains high oxygen content, reactive nature, and poor heating value and hence require upgradation prior to its utilization as fuel. It is desirable to convert the oxygenated compounds of bio-oil into oxygen deficient compounds in the context of converting biomass to biofuel. In this work, we show the generation of hydrocarbon-rich bio-oil from grassy biomass (taking Napier grass as a model compound) using vacuum pyrolysis coupled with online upgradation (or deoxygenation) of volatile products over an iron bed. A comparison between individual pyrolysis products, especially liquid compounds, without and with vapor upgradation treatment, is presented. Online deoxygenation of pyrolysis volatile products over iron bed significantly reduced oxygenated compounds within bio-oil and increased the formation of hydrocarbons. Pyrolysis gases after deoxygenation treatment predominantly contained hydrogen along with C 1 – C 4 hydrocarbons, carbon dioxide, and carbon monoxide. Amongst liquid products, bio-oil mainly contained C 9 – C 23 hydrocarbons, phenols, and aldehydes, while, aqueous phase contained dissolved organics as alcohol, acid, aldehyde, phenolic compounds, and sugar chemicals. Additionally, the amorphous and alkaline biochar comprised of nanoparticles, having the porous surface and various functionalities suitable for acidic soil. Moreover, a reaction scheme for Napier grass-derived products is proposed. Highlights • Production of hydrocarbon rich bio-oil from grassy biomass pyrolysis is reported. • All the pyrolysis products of Napier grass are characterized for the first time. • Apart from bio-oil various chemicals are also recovered in the current process. • Reaction mechanisms for Napier grass-derived products are proposed. • Catalyst regeneration and process sustainability in terms of energy is presented. [ABSTRACT FROM AUTHOR]

Steam pyrolysis of N,N,N’,N’-tetrabutyldiglycolamide (TBDGA) is investigated in a non-catalytic tubular reactor for complete gasification as a waste management method for solvents used in Nuclear Industry. A total of 19 products have been identified in the product streams and quantified to get complete material balance under varying operating conditions of the process at atmospheric pressure. The optimized reaction parameters for the complete gasification of TBDGA were temperature of 1050 °C, water to TBDGA molar ratio of 124 and TBDGA’s flow rate of 5.7 g h −1 . [ABSTRACT FROM AUTHOR]

A green method usingJuglans regiabark extract was used to synthesize silver nanoparticles at room temperature with monitoring by absorption spectroscopy. The size and shape of the synthesized nanoparticles were characterized by infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and small-angle X-ray scattering. The average particle size was from 10 to 30 nm. Gas chromatography–mass spectrometry (GC–MS) was used for the separation, identification, and quantification of components of the plant extracts. A possible mechanism for the synthesis of nanoparticles was elucidated based on the GC–MS results. The synthesized silver nanoparticles showed effective inhibition againstStreptococcus mutans, which is the main causative agent for dental caries. The nanoparticles also showed promising antibiofilm activity by inhibiting the glucosyltransferase enzyme. [ABSTRACT FROM PUBLISHER]

A process for continuous synthesis of cross-linked chitosan-sodium tripolyphosphate (CS-TPP) nanoparticles is optimized using microreactors for its comparison with a batch stirred reactor. The effect of various parameters including residence time, concentration of CS, pH of the CS solutions, and stabilizing surfactant concentration was modeled by population balance equations (PBEs) to determine size, growth, and nucleation rates of the CS-TPP nanoparticles. The smallest particle size was obtained at lower residence time, lower concentration of CS, pH 5, and using a surfactant concentration above its critical micellar concentration. The particles obtained from the microreactors are agglomerated but are smaller in size as compared to those obtained from the batch reactor. The system was also optimized for the minimum particle size applying the estimated growth rate and the PBEs. [ABSTRACT FROM AUTHOR]

A continuous biodiesel production process from palm fatty acid distillate (PFAD) is simulated in Aspen Plus for process engineering aspects emphasizing the critical points in the entire process. The production process involves acid-catalyzed hydrolysis of residual glycerides of PFAD to additional free fatty acids (FFAs), followed by esterification of the FFAs with methanol for methyl ester production, biodiesel purification, and finally methanol recovery. A two-phase kinetic model was employed with detailed operating conditions for both, homogeneous and heterogeneous catalysts to design the reactors and critical process units. The operating costs of the process using both catalysts are evaluated. [ABSTRACT FROM AUTHOR]

Abstract: A process for the delignification of sugarcane bagasse using aqueous hydrotropic solutions is investigated. The optimum conditions for the maximum delignification (85%) of bagssse comprise of temperature (388K), hydrotrope concentration (30% w/w), and bagasse loading (5wt%) in 240min. The delignification process was modeled as the extraction of lignin from the solid biomatrix to estimate its diffusivity at 3.43×10−13 m2/s and activation energy 16.2kJ/mole. The isolated lignin is characterized in detail for surface functionality, nature and morphology (irregular shape, flaky/smooth surface, and amorphous nature), molecular weight (3791g/mole), phenolic compounds, and thermal stability (633K), by using, infrared spectrocopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), gel permeation chromatography (GPC), mass spectroscopy, UV spectroscopy, and differential scanning calorimetry analysis (DSC), respectively. The bagasse delignification using aqueous hydrotropic solutions has potential to overcome the problem of breaking of the cellulosic material in the conventional delignification processes. [Copyright &y& Elsevier]

Thiswork presents the development and experimental validationof a mathematical model for the steam pyrolysis process for the thermaldegradation of CHON amides. Experimental data on the steam pyrolysisof dimethylformamide (DMF) in a nonisothermal tubular stainless steelreactor for different residence times over the temperature range of973–1273 K were used to develop a reaction network involving15 components and 10 reactions to model the process. The General ProcessModeling System (gPROMS) was used for kinetic parameter estimationand simulation. The model simulations results were found to agreewell with experiments carried out over a wide range of operating conditions. [ABSTRACT FROM AUTHOR]

Abstract: A non-catalytic steam pyrolysis of N,N-dimethyl formamide (DMF) was studied in a SS 316 plug flow reactor at atmospheric pressure as a waste solvent minimization method. The reaction products were analyzed by using gas chromatography-thermal conductivity detector and high performance liquid chromatography-refractive index detector. The optimization of process variables namely, temperature, flow rate and water to DMF ratio (v/v) for the maximum conversion of DMF have been studied by response surface methodology (RSM) coupled with a Box-Behnken design. The analysis of variance (ANOVA) data shows the conversion of DMF significantly enhances with temperature. Higher flow rate has adverse effect on DMF conversion, whereas water to DMF ratio (v/v) shows negligible effect on conversion of DMF. With the help of a developed RSM model, the highest conversion of DMF (89.82wt%) was predicted at 1100°C, 0.48ml/min and water:DMF ratio of 1.35 (v/v). Based on the experimental design, eight empirical models were developed those depict the interacting effect of different sets of operating variables on conversion of DMF and yield of seven products. Effect of process variables on yield of CO2 and N2 were studied, individually. Oxidative pyrolysis of DMF was also investigated, which shows significant reduction in the coke formation with increasing H2O2 to DMF mol ratio. [Copyright &y& Elsevier]

Abstract: Photoswitchable hydrotropic solubilization has been investigated by cis–trans isomerization about the olefinic bond of sodium cinnamate (Na-CIN) for various solutes such as cinnamic acid, aspartic acid, curcumin, thymol, and benzocaine. The extent and rate of isomerization depend on the concentration of Na-CIN and temperature. The cis–trans isomerization of Na-CIN by UV irradiation allows recovery of the solute from aqueous Na-CIN solutions, without dilution by water. Extraction of forskolin and curcumin from coleus forskholii and curcuma longa, was also studied for recovery under UV irradiation. [Copyright &y& Elsevier]

Organosulfur compounds were removed from commercial diesel by reactive adsorption on metal impregnated functionalized polymers at ambient temperature and pressure. The equilibrium adsorption capacities of Ag+ and Cu+ impregnated resins for dibenzothiophene (DBT) are 13 mg/gm and 9.6 mg/gm. Adsorption and desorption cycle studies in a column packed with Ag+ and Cu+ loaded BSR resin showed intraparticle resistance affecting uptake of the sulfur compounds. Only 40% of the adsorbed organo-sulfur compounds was recovered by solvent regeneration using toluene, but complete regeneration of the bed was possible by simultaneous microwave heating. Density functional theory (DFT) calculations show stronger interaction between organosulfur compounds and Cu(I) on the polymer resins. The interaction energy increases with the number of substituents around 'S' in the structure, giving stronger interaction of the metal ions with dialkyl-substituted dibenzothiophene than monosubstituted and unsubstituted thiophene. [ABSTRACT FROM AUTHOR]

Partitioning of o/p-nitrophenols between organic solvents and water in the presence of hydrotropes such as sodium toluene sulfonate, sodium xylene sulfonate, and sodium cumene sulfonate, has been experimentally investigated and modelled in terms of co-aggregation of the hydrotrope and nitrophenols in aqueous solutions. The phenol-hydrotrope and hydrotrope-hydrotrope interactions are characterized by an aggregation model. The experimental data for a series of hydrotropes are further used to predict the partitioning behavior of p-nitrophenol in the presence of sodium butyl benzene sulfonate (Na-NBBS). The aggregation number of NaNBBS, (∼30) obtained from the partitioning data, matches well with that obtained by small angle neutron scattering. [ABSTRACT FROM AUTHOR]

Abstract: Molecular mechanics(MM) calculations for interfacial behaviour of sodium n-butyl benzene sulfonate (NaNBBS), sodium iso-butyl benzene sulfonate (NaIBBS) and sodium tert-butyl benzene sulfonate (NaTBBS) show a significant effect of the butyl group geometry on the surface area occupied by these molecules at the air–water interface. NaNBBS, in comparison with NaIBBS and NaTBBS, shows a closer molecular packing at the interface. The simulation predicts minimum hydrotrope concentration of each hydrotrope to reach surface saturation and molecular surface area at the interface match with good accuracy. The shape, size and charge of the hydrotrope aggregates obtained by molecular dynamics simulation also match well with the results of small angle neutron scattering experiments on the same hydrotrope. The simulation shows non-regular and ellipsoidal hydrotropes aggregates with substantial charge on the surface. The aggregates are also more open structures as compared to surfactant micelles. The water accessible surface area of a NaNBBS aggregate was 25% lower in comparison to that of NaTBBS aggregate, indicating closer packing of NaNBBS molecules. The fractional charge on the NaNBBS aggregate decreases with the increase in the number of NaNBBS molecules in the aggregate indicating more counter-ion association. [Copyright &y& Elsevier]

Reverse micellar solutions(RMS) of sodium bis- (2-ethylhexyl)-sulfosuccinate (AOT) in aliphatic organic solvents were used for permeabilization and protein removal directly from Aspergillus niger cells. Most of the cell wall proteins (∼95-100%) were solubilized into the reverse micelles solutions. A significant fraction of intracellular catalase (26-30%) permeates out of the cells and remains on the cell surface and is recovered in a cell wash. Because of it's size the catalase in not solubilized in the RM water pools and thus is not detected in the stripping solution used to recover other proteins from the organic reverse micellar solutions. The remaining amount of catalase is recovered by breaking the cells in purer form. Multiple extractions were used for the extraction of the cell wall proteins followed by ultrasonication of the cells to recover intracellular catalase in a purified form. Therefore, catalase with 5 fold purification was recovered in 88% yield from the RMS- treated cells. [ABSTRACT FROM AUTHOR]

Purification of glucose isomerase by its partitioning in a PEG‐salt aqueous two‐phase system (ATPS) in the presence of PEG derivatives has been studied. Selective partitioning of the proteins was observed towards the PEG phase containing PEG‐benzoate and PEG‐palmitate, enriching glucose isomerase in the salt phase. Cross‐current extraction in 4 stages in the presence of PEG‐palmitate gave an enrichment factor of ∼⃒5 for the enzyme. After initial purification with ATPS, glucose isomerase was immobilized on cross‐linked chitosan beads. The immobilized enzyme was stable over a wider pH range (5.2–9.0) and showed an optimum pH of 6.5 [ABSTRACT FROM AUTHOR]

Strong and weakly acidic ion exchange resins and polymeric adsorbents are used for recovery of 1,4‐dimethyl piperazine (DMP) from aqueous solutions. Sorption of the amine in undissociated form is the primary mechanism of uptake of DMP on the ion‐exchange resins. Equilibrium adsorption data for DMP on the resins, at various temperatures, are fitted in Langmuir adsorption isotherm. Kinetic studies show that intraparticle diffusional resistance controls the sorption of DMP into the resin matrix. A mathematical model based on intraparticle diffusion and external mass transfer is used for simulating breakthrough profiles and compared with the experimental results for a fixed bed of weakly acidic Indion‐652 resin. The DMP loaded bed of the resin was effectively regenerated with methanol. [ABSTRACT FROM AUTHOR]

Separation of o -/ p -aminoacetophenones ( o -/ p -AAPs) is investigated by a two-step process: selective solubilization in an organic solvent followed by reactive adsorption on functionalized polymers. Since, p -AAP and o -AAP show inter- and intra-molecular hydrogen bonding, respectively, the former is solubilized to a much lesser extent than the latter in an organic solvent. For example, o -AAP dissolves completely while p -AAP shows only 1.8% saturation solubility in toluene. Selective solubilization of o -AAP in toluene, therefore, gives pure p -AAP as residual solid in high yields. In the subsequent adsorption step, a strongly acidic ion exchange resin removes selectively the trace amounts of p -AAP from the toluene phase giving pure o -AAP. [ABSTRACT FROM AUTHOR]

Abstract: The yeast cell wall is highly resistant towards chemical permeabilization. In the present work, reverse micellar solutions (RMSs) of sodium di (2-ethylhexyl) sulfosuccinate (AOT) in aliphatic hydrocarbons along with aqueous solutions of various surfactants, hydrotropes and amino acids have been examined for their ability to permeabilize baker''s yeast cells. Although a substantial amount of cellular proteins was released on treatment with RMSs, higher molecular weight proteins such as invertase (INV), alcohol dehydrogenase (ADH) and alkaline phosphatase (AP) were retained within the cell. Treatment of intact yeast cells with aqueous cysteine solutions not only resulted in specific release of invertase but it also made the cells more fragile, enhancing the release of proteins/enzymes in the subsequent cell permeabilization steps. A multi-step procedure comprising of cysteine treatment as the first step (a purification factor of 40 for invertase), followed by reverse micellar solid–liquid extraction (RME) removed most of the proteins from the cells. Finally, sonication released the intracellular enzymes ADH and AP in a comparatively purer form with ∼90–95% recovery. [Copyright &y& Elsevier]

Precipitation of piperine from aqueous hydrotropic solutions of sodium cumene sulfonate was investigated in a laboratory-scale agitated vessel by cooling aqueous sodium cumene sulfonate solution saturated with piperine from 353 K to 303 K. This temperature swing is a more economical approach than usual dilution by water for recovery of piperine from hydrotrope solutions. The time evolution of crystal size distribution was used to deduce simultaneously crystal nucleation and growth kinetics. The results indicate higher nucleation and slower crystal growth rates and thus formation of very fine crystals of piperine in the range of 1–400 µm. [ABSTRACT FROM AUTHOR]

Adsorption of penicillin acylase (PA) from a crude aqueous extract of Escherichia coli on chitosan beads and N-benzamide and N-phenylacetamide derivatives of chitosan was investigated. Penicillin acylase adsorbed specifically on the derivatized chitosan beads, with a strong interaction with the ligand groups. The interaction of the active site of PA with the affinity ligands was simulated by molecular modeling. The adsorbent was further used for immobilization of PA by using glutaraldehyde as the activating agent. The immobilized enzyme retained the same activity even after 20 weeks. [ABSTRACT FROM AUTHOR]

o-/p-Nitroanilines (o-/p-NAs), which are intermediates for pharmaceutical and dye industries, show widely different solubilization behavior in an organic solvent. For example, o-Nitroaniline (o-NA) dissolves well in toluene, but p-nitroaniline (p-NA) does not. The intermolecular hydrogen bonding among the molecules of p-NA resists its solubilization in poorly solvating solvents. A selective solubilization of o-NA from the mixture thus gives pure p-NA as a solid product and an o-NA rich solution in toluene with trace amounts of p-NA. These traces of p-NA could be removed by selective sorption on an acidic resin. The sorption of nitroanilines, individually and in mixture, therefore, was experimentally investigated from their solutions in toluene and methanol, by using a strongly acidic resin, Indion 190, with sulfonic acid groups. The molecular modeling studies confirmed the Lewis acid–base interactions between the resin's sulfonic acid group and p-NA's nitro group. The selective sorption is further aided by poor solvation of p-NA in the organic solvents. [ABSTRACT FROM AUTHOR]

The partitioning of penicillin acylase from E. coli in PEG–salt aqueous two-phase system in the presence of modified PEGs, i.e. PEG-benzoate (PEG-Bz), PEG-phosphate (PEG-PO4), PEG-trimethylamine (PEG-tma), PEG-palmitate (PEG-pal), and PEG-phenylacetamide (PEG-paa) has been studied. For each PEG-derivative, the phase diagram was constructed and selective extraction of the enzyme was investigated. Since, in the case of PEG-Bz and PEG-paa, the activity of the enzyme decreased in the PEG-rich phase, the possibility of the specific group binding to the active site of the enzyme was investigated by molecular simulation. [Copyright &y& Elsevier]

Water-in-hexane macro- and micro-emulsions stabilized by sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) were used for selective permeabilization of Escherichia coli cells to extract penicillin acylase (3.5.1.11). Various organic solvents and surfactants were compared for the yield and purification of the enzyme. Recoveries upto 144% with respect to sonication and specific activity of the enzyme upto 26 units mg−1 have been achieved. Due to low solubilities of AOT and aliphatic hydrocarbons in water the recovered enzyme was free from contaminants. A possible mechanism for cell permeabilization and enzyme purification by reverse micellar treatment is proposed. [Copyright &y& Elsevier]

We report formation of polymorphs and new eutectics and cocrystals of curcumin, a sparingly water-soluble active component in turmeric, structurally similar to cinnamic acid. The curcumin polymorphs were formed using liquid antisolvent precipitation, where acetone acted as a solvent and water was used as the antisolvent. The metastable form 2 of curcumin was successfully prepared in varied morphology over a wide range of solvent-to-antisolvent ratio and under acidic pH conditions. We also report formation of new eutectics and cocrystals of curcumin with cinnamic acid acting as a coformer. The binary phase diagrams were studied using differential scanning calorimetry and predicted formation of the eutectics at the curcumin mole fraction of 0.15 and 0.33, whereas a cocrystal was formed at 0.3 mole fraction of curcumin in the curcumin–cinnamic acid mixture. The formation of the cocrystal was supported with X-ray powder diffraction, the enthalpy of fusion values, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The hydrogen bond interaction between curcumin and cinnamic acid was predicted from Fourier-transform infrared spectra, individually optimized curcumin and cinnamic acid structures by quantum mechanical calculations using Gaussian-09 and their respective unit cell packing structures. [ABSTRACT FROM AUTHOR]

A continuous flow synthesis of tryptophol is developed in a tubular reactor at different temperatures and flow rates, by Fischer indole synthesis route using phenyl hydrazine hydrochloride (PHH) and 2,3-dihydrofuran (DHF) as starting materials. The maximum conversion of PHH was 93%, and the yield of tryptophol was 72% in 6 min. A kinetic model is proposed for the process by taking into account the formation of intermediate species. The reactor was simulated in COMSOL platform for temperature profiles in the reactor, which were subsequently used to estimate the kinetic parameters of the reaction. The reaction was further intensified by executing the reaction in a continuous microwave reactor (CMWR), at different flow rates and at different power. The maximum conversion of PHH was obtained to be 91%, and the yield of tryptophol was 95% in 5 min using CMWR. [ABSTRACT FROM AUTHOR]

A Reaction Network model of 16 series-parallel reactions involving total 19 components is developed to represent the steam pyrolysis of tetrabutyldiglycolamide, a tridentate extractant used for selective extraction of actinides and lanthanides in nuclear industry, in a continuous tubular reactor. The kinetic parameters of the entire reaction network were optimized simultaneously and validated against the set of experimental results at different operating conditions. The reaction network model was successfully used for simulation of the pyrolytic reactor in General Process Modelling (gPROM) environment. The steam pyrolysis provides an efficient waste management method in nuclear as well as other industries treating concentrated organics waste streams that leaves no solid residue. [ABSTRACT FROM AUTHOR]

Equilibrium adsorption studies of CO 2 , CH 4 and N 2 were carried out with polystyrene based adsorbent, functionalized with heterocyclic ligands, viz . citrazinic acid (CA), 4-hydroxymethyl pyridine (MP) and 2,6-bis-imidazo-1-yl-pyridine-4-carboxylic acid (BIMP) using batch adsorption and pulse chromatography technique. The equilibrium uptakes of CO 2 , CH 4 and N 2 for all the adsorbents were determined at atmospheric and high pressures. The equilibrium adsorption constants and selectivities were estimated by fitting of experimental chromatograms obtained from pulse chromatography studies into linear equilibrium dispersive chromatography model using gPROMS. The BIMP functionalized polystyrene adsorbent showed the highest equilibrium uptake and selectivity for CO 2 . [ABSTRACT FROM AUTHOR]

Esterification of palm fatty acid distillate with methanol was investigated for intrinsic kinetics and regarding the effect of catalyst loading, temperature, and methanol to feed molar ratio using ionic liquid acidic catalysts covalently attached to a polystyrene support. The kinetic parameters of the Langmuir-Hinshelwood-Hougan-Watson model of the reaction are determined for comparison with those using p-toluenesulfonic acid and methanesulfonic acid as homogeneous catalysts considering the phase split of the reaction mixture into two liquid phases during the reaction. The intrinsic parameters could predict the dynamic behavior of the system under various operating conditions. [ABSTRACT FROM AUTHOR]

Two new fatty acid based derivatives containing carboxylateandamide functions with different alkyl chain lengths were synthesized,and their properties as low molecular weight (LMW) gelators for organicsolvents such as nitrobenzene, chlorobenzene, dichlorobenzene, anddioxane are evaluated. The xerogels under Scanning Electron Microscope(SEM) show self-assembled fibrillar and flowerlike structures. Rheologicalproperties of the gelator forming an extended fibrillar network werestudied to verify the solidlike behavior of the gel. The role of intermolecularhydrogen bonding in the formation of the supramolecular structureswas confirmed through FTIR spectroscopy. The nitrobenzene based organogelsuperstructure was used as a template for synthesis of CdS nanoparticles.The nanoparticles were characterized through UV–vis spectroscopyand Transmission Electron Microscopy (TEM). [ABSTRACT FROM AUTHOR]

This report relates to synthesis of functionalized polymericadsorbentsfor selective removal of silver ion in the presence of platinum(II)from crude oxaliplatin, thus providing an effective method for itspurification with a desired impurity profile for silver. Two chelatingligands, thiourea and thiosemicarbazide, were grafted on styrene backbonecross-linked with 2% divinyl benzene (DVB) and tested by batch adsorptionstudies for the uptake of silver and platinum. The maximum sorptioncapacity values for both the adsorbents for Ag+were 101.58and 67.75 (mg/g), respectively, with an exceptionally high value ofseparation factor (α = 1155 and 231) over platinum. The experimentalsorption data were fitted well with the Langmuir model. Desorptionof silver from the polymer can be achieved by using 0.3 M Na2S solution for regeneration. [ABSTRACT FROM AUTHOR]

Abstract: The rheological behavior of mixed aqueous solutions of cetyl trimethylammonium bromide (CTAB) and anionic hydrotropes, such as sodium salts of n-butyl benzene sulfonate (Na-NBBS), iso-butyl benzene sulfonate (Na-IBBS) and tert-butyl benzene sulfonate (Na-TBBS), has been studied over a range of the hydrotrope concentration at different temperatures. The zero shear viscosity measurements for the mixed systems show a bimodal curve with a first viscosity maximum at a Na-BBS/CTAB ratio of approximately 0.3 and other ones at about 2.5. The three isomers of butyl benzene sulfonate (BBS) differ in their effects on the viscosity of the solutions. The difference in the viscosities of the mixed CTAB–hydrotrope solutions is more prominent at higher values of Na-BBS/CTAB ratio. Since the viscosity depends on the microstructure generated by the CTAB-BBS mixtures in solutions, the size and shape of the mixed micelles varies with the structure of the butyl group. The linear NBBS induces higher changes even at lower concentrations. The CTAB-hydrotrope solutions in the region of the first viscosity maxima exhibit Maxwellian fluid behavior where the mixed system is highly viscoelastic and the micelles are entangled. In the region of second viscosity maxima, however, the mixed solutions are non-viscoelastic with much lower values of storage and loss modulii. The living polymer formation by linear growth of CTAB micelles, on addition of hydrotropes, to very large aggregation number is evidenced from intrinsic viscosity and rheological properties of solutions. [Copyright &y& Elsevier]

A reactive sorption method has been devised for the purification of artemisinin from Artemisia annua extract using a polymeric adsorbent loaded with specific ligands. These ligands were designed by molecular simulation to selectively adsorb artemisinin. The specific interactions of artemisinin with different polymeric adsorbents in organic solvents of varying polarity were further quantified in terms of interaction energy, atomic charges, and vibrational spectral analysis. Solvation studies indicate use of methanol for adsorption while ethyl acetate for desorption of artemisinin. Batch equilibrium and dynamic adsorption-desorption studies were conducted to establish optimum parameters for the purification process. A weakly basic polymeric adsorbent with tertiary amino groups was chosen for artemisinic acid. After adsorption the final purity of artemisinin increases up to 90%. [ABSTRACT FROM PUBLISHER]

Abstract: In the present work, experimental investigations have been carried out on ejectors employing air as a motive fluid and water as the entrained fluid. A semi-empirical model has been developed to predict the liquid entrainment rate taking into account: (i) the compressible nature of air, (ii) pressure drop for two-phase flow and (iii) losses due to changes in cross sectional area. The effects of gas velocity, liquid level in the suction chamber, nozzle diameter and throat diameter on the liquid entrainment, entrainment ratio (L/G), pressure drop, gas hold-up, mass transfer coefficient and interfacial area have been investigated. The liquid entrainment rate increases with the increased liquid level in the suction chamber and with the increase in gas velocity. The ratio of throat cross sectional area to the nozzle cross sectional area (area ratio) was found to be a critical parameter. These results have been explained on the basis of pressure profiles of ejector (along the centre line of the ejector). The liquid entrainment rate predicted from the semi-empirical model is in good agreement with the experimental values. The mass transfer coefficient and interfacial area increase with increase in gas velocity. Correlations have been proposed to estimate the fractional gas hold-up, mass transfer coefficient and interfacial area in the ejectors. [Copyright &y& Elsevier]

Purification of glucose oxidase from Aspergillus niger and that of β-galactosidase from Kluyveromyces lactis have been attempted using poly(ethylene glycol) (PEG)-sodium sulfate aqueous two phase system (ATPS) in the presence of PEG-derivatives, i.e. PEG-Coomassie brilliant blue G-250 and PEG-benzoate, PEG-palmitate and PEG-TMA, respectively. The enzymes showed poor partitioning towards the PEG phase in comparison with other proteins in ATPS containing no ligands. Selective partitioning of other proteins was observed towards the PEG phase in the presence of PEG-benzoate and PEG-palmitate enriching β-galactosidase in the salt phase whereas in the case of glucose oxidase, PEG-Coomassie brilliant blue G-250 derivative worked as a better affinity ligand for other proteins. A 19-fold purification was obtained with the PEG dye derivative after 5 stage cross extractions with 80% recovery of glucose oxidase and an enrichment factor upto ∼7 for β-galactosidase with the PEG-TMA derivative. The interaction of PEG-benzoate and PEG-TMA ligands with the active site of β-galactosidase has been evaluated by molecular modeling. The effect of the molecular weight of glucose oxidase on its partitioning was confirmed as the molecular simulation shows strong affinity interaction of PEG-glucoside with the enzyme. [ABSTRACT FROM AUTHOR]

Abstract: Aqueous solutions of sodium cumene sulfonate are characterized by various experimental techniques for its aggregation behavior as a function of temperature. Surface tensiometry, volumetric changes, vapor pressure osmometry, fluorescence polarization studies and enthalpy changes show changes in the solutions with increasing concentration and temperature. The apparent and partial molal volumes of the hydrotrope, derived from the density measurements, show a sharp increase at a characteristic minimum hydrotrope concentration. The osmotic coefficient of NaCS, obtained from vapor pressure osmometry, shows a significant deviation indicating aggregation of the hydrotrope molecules in aqueous solutions. NaCS, when used as an intrinsic fluorescent probe, reveals a non-polar environment in the aggregate with substantial microviscosity. The enthalpies of micellization obtained directly from the calorimetric measurements show a trend towards lower values with increasing temperature. [Copyright &y& Elsevier]

Separation of nitrophenols (NP) has been studied by selective solubilization in organic solvents of different polarities. o‐NP dissolves very well in heptane and toluene while intermolecular hydrogen bonding among p‐NP molecules decreases its solubilization in these solvents. Thus partial separation of o‐/p‐nitrophenols is achieved by selective solubilization of o‐NP in heptane. The trace amounts of p‐NP from the o‐NP solutions are removed by its selective sorption on basic ion exchange resins. The sorption of nitrophenols, individually and in mixtures, is experimentally determined from their solutions in heptane, toluene, and methanol by using weakly basic Indion‐850 and Duolite A‐308 resins and strongly basic Indion‐810 resin. The equilibrium adsorption studies show very selective adsorption of p‐NP from heptane with a high loading capacity on Indion‐850. [ABSTRACT FROM AUTHOR]

The turmeric rhizome (Curcuma longa) contains curcuminoids embedded in the starch matrix. It is thus important to target starch hydrolysis to enhance extraction of curcuminoids. In the case of starch hydrolysis, α-amylase is more efficient when the starch is in a gelatinised form than when it is in its natural form. The present work includes hydrolysis of turmeric starch in its natural and gelatinised forms using α-amylase in hydrotrope solution (HS) and scCO2. The optimum rate of starch hydrolysis was obtained using 200 IU cm−3 of α-amylase, at reaction conditions of 6.5 pH at 328 K when 10% w/w of turmeric powder was stirred at 900 rpm in HSs. The hydrolysis in 15 MPa scCO2 at room temperature required a phase modifier and 40 min of residence time (RT). The enzyme treatment of turmeric powder in HSs increased the filtration rate for curcuminoid extraction (gelatinised and native) compared to untreated turmeric powder. [ABSTRACT FROM AUTHOR]

Ionic liquids, forming a newer class of green solvents, have shown potential in solvent extraction due to their remarkable physical and chemical properties, which can be tailored for specific tasks. Ionic liquids are one of the potential extractants for desulphurization of crude oil to produce ultra-low sulphur fuels. However, due to the constraints of economic feasibility and the broad domain of Ionic liquids, their varying affinity towards sulphur impurities along with the overall expensive methods of production, limit the selection of an Ionic Liquid that provides optimum extraction rates. We investigated the biphasic extraction of two sulphur compounds, thiophene and dibenzothiophene (DBT) from dodecane by using ionic liquid systems of ethyl methyl imidazolium (EMI) and butyl methyl imidazolium (BMI) cations; and tetrafluoroborate (BF4) and thiocyanate (SCN) anions. The molecular arrangement and extraction mechanism of both sulphur compounds at the interface of dodecane-ionic liquid system are studied by molecular dynamics (MD) simulations. We observed that electrostatic interactions between the aromatic plane of sulphur compounds and cations of ionic liquids are the major forces responsible for the extraction of sulphur compounds. [ABSTRACT FROM AUTHOR]

Deep desulfurization of fuels by using ionic liquids (ILs) has gained notable attention and has been a subject of concern. This study aims at the extraction tendencies of two alkylated derivatives of an aromatic sulfur compound, 4-Methyldibenzothiophene (MDBT) and 4,6-Dimethyldibenzothiophene (DMDBT) from oil using four ILs namely, Ethylmethylimidazolium tetrafluoroborate [EMIM][TFB], Butylmethylimidazolium tetrafluoroborate [BMIM][TFB], Ethylmethylimidazolium thiocyanate [EMIM][SCN], Butylmethylimidazolium thiocyanate [BMIM][SCN] via molecular dynamics simulation. A interfacial phenomena of extraction pathway of MDBT and DMDBT in biphasic system of dodecane and ILs was studied at molecular level. The transfer of sulfur compounds during the extraction processes, were observed to be controlled by type of IL as well as sulfur compound and interfacial resistance. This study will also help in selecting an appropriate IL as an extractant and improving the process conditions. [ABSTRACT FROM AUTHOR]

The molecular dynamics (MD) simulation of TODGA in n-dodecane shows formation of nanostructures of TODGA aggregates with nitric acid and water. These aggregates are dispersed in dodecane phase or form well defined reverse micelles grown sufficient in size depending on the acid concentration. With increasing nitric acid concentration, aggregation number of TODGA in reverse micelles also increases which, however, is independent of TODGA concentration. Aggregation number rises from 2 to 8 in presence of 0-3.5 M nitric acid in corresponding aqueous phase. The formation of the aggregates explains remarkable acid co-extraction from aqueous phase to organic dodecane phase by TODGA. [ABSTRACT FROM AUTHOR]

The need to produce Hydrogen in an environmentally friendly manner has increased as the transportation industry has started to employ cleaner sources of energy. One of the cleaner ways to produce H 2, is to use the Bunsen S-I cycle. This includes the separation of the H 2 from an ionic mixture of Hydrogen Iodide and water using distillation. In this work, the Pitzer’s model for electrolyte solutions has been employed to represent the vapour-liquid equilibrium (VLE) of the binary system of HI and H 2 O. The activity coefficient (γ) is calculated from the equation which indicated the non-ideal nature of the system and aided the calculation of the vapour phase mole fraction. The experimental VLE data was obtained from a recirculating still at 101.3 kPa pressure for the binary system. This experimental data and data from literature was used to estimate the parameters of the Pitzer’s model to represent the activity coefficient of HI in this mixture. These optimized parameters could explain all the variations in the data with more that 90% accuracy for most of the data, with an average standard deviation of about 0.04. Furthermore, the temperature dependent form of the Pitzer’s equation was used to predict the VLE data at higher pressures of 3 and 5.7 bars and higher temperature conditions. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulation of [Cd(II)] along with nitrate ions and water in dodecane was carried out for different nitric acid concentrations. The extraction process using N,N,N’,N’-tetraoctyldiglycolamide (TODGA) and tributyl phosphate (TBP), in biphasic systems, is also simulated at three nitric acid concentrations. In the TBP-based system, the formation of a third phase was observed at 3 M nitric acid concentration. Cd(II) ions form reverse micelles-like clusters with TODGA as an extractant in dodecane. The mass percentage of TODGA in these clusters decreases with increase in the acid concentration while increasing the size of the aggregates at the same time. [ABSTRACT FROM PUBLISHER]

Nitric acid extraction by tri-n-butyl phosphate (TBP) in dodecane is investigated by molecular dynamics (MD) simulation, for different concentrations of TBP in the range 0.1 M to 2 M with aqueous phase HNO 3 concentration of 1 M, 2 M and 3 M. The MD studies are carried out considering dissociated as well as molecular forms of HNO 3 . The simulations showed formation of a third phase consisting of TBP, HNO 3 and water which is in agreement with reported experimental results. HNO 3 , in dissociated form, shows formation of NO 3 − and H 3 O + pockets in the third phase while HNO 3 in molecular form remains dispersed in the third phase without such specific formations. The impact of concentrations of the acid and TBP on the third phase formation, reverse micelles of TBP in dodecane and NO 3 − and H 3 O + pockets in the third phase, have been demonstrated. The estimated diffusion coefficient values of TBP and dodecane match well with the reported literature values. [ABSTRACT FROM AUTHOR]

A facile low temperature approach was used to synthesize γ-MnO2 on the surface of graphene oxide (GO) through a simple wet precipitation method using MnSO4 as a precursor. X-ray diffraction analysis and Raman spectroscopy confirmed the formation of γ-phase MnO2 in the MnO2/GO nanocomposites. Transmission electron microscopy studies showed that γ-MnO2 exists as flower and needle structures in GO with an average size of approximately 15 nm. Inductively coupled plasma atomic emission spectroscopy studies confirmed a 62.5 wt% loading of γ-MnO2 in the GO nanocomposites. The γ-MnO2/GO catalyst shows good activity for the selective aerobic oxidation of benzyl alcohols to corresponding carbonyl compounds even when present in sub-stoichiometric amounts giving 91% yield over 3 h under mild reaction conditions. The catalyst showed high activity even after three cycles indicating good recyclability. [ABSTRACT FROM AUTHOR]

The crude oil and vacuum residue (VR), when subjected to the hydrodynamic cavitation (HC) or microwave irradiation, showed cracking of larger molecular weight compounds into smaller molecules. The productivity of light and intermediate petroleum fractions of the crude after the HC treatment increased in the range of 3–7%, while the microwave treatment with activated carbon as an efficient microwave absorber showed 12% conversion of VR into distillate products. The HC altered the density, viscosity, iodine values and % of distillate fractions marginally, but significantly changed the light and middle distillates recovery, and the carbon number profiles of the crude. [ABSTRACT FROM AUTHOR]

Adsorption of CO2, CH4, and N2was investigated using pulse concentration chromatography on polystyrene functionalized by covalently attached diethanolamine, dimethylamine, imidazole, and N-methyl piperazine. The adsorption equilibrium constants at different temperatures were estimated by fitting the experimental chromatograms into a non-linear equilibrium dispersive chromatography model using gPROMS. Axial dispersion was found to be the controlling mechanism for dispersion of the chromatograms. The heat of adsorption and corresponding equilibrium selectivities were determined from the adsorption equilibrium constants. The imidazole based adsorbent showed the highest affinity for CO2. [ABSTRACT FROM PUBLISHER]

Adsorption of CO2, CH4, and N2has been investigated using amine functionalized polymeric resins having diethanolamine, imidazole, dimethylamine, and N-methyl piperazine covalently attached to the styrene-divinyl benzene copolymer (PS) matrix. The equilibrium adsorption of CO2, CH4, and N2was examined on these functionalized polymers at pressures from atmospheric to 40 atm for CO2and N2while up to 10 atm for CH4at 303 K. PS-Imidazole showed the highest adsorption capacity for CO2as compared to other functionalized polymers. No significant uptake of CH4and N2was observed at low pressures by any of the functionalized polymers. The adsorption isotherms were analyzed using dual mode sorption model and Ideal Adsorbed Solution Theory (IAST). [ABSTRACT FROM PUBLISHER]

Thechanges in interfacial tension against water, density, andcoefficient of viscosity of a binary mixture of tri-iso-amyl phosphate (TiAP) and n-dodecane have been measuredbefore and after gamma radiolysis. Density, viscosity, and interfacialtension of binary mixtures are additive functions of mole fractionsof TiAP and gamma absorbed dose, which respectively form a plane inthree-dimensional plots of linear–linear–linear, loge–loge–linear, and loge–loge–linear scales. Logarithmic interfacialtension also forms a three-dimensional plane with density and viscosityin loge–linear–linear plot. Redlich–Kistertype equations (RK-eq) have been introduced to model excess propertiesof binary mixtures, where a second independent variable is the absorbeddose. The parametric coefficients of RK-eqs pertaining to excess molarvolume, viscosity deviations, and interfacial tension deviations ofthe mixtures are linear functions of the absorbed dose. Molecularinteractions between solute–solute and solute–solventhave also been quantified in terms of apparent molar volume at infinitedilution, among others. [ABSTRACT FROM AUTHOR]

Correlations proposed in this workpredict density and viscositywith better accuracy in comparison with existing correlations. Dimensionlessspecific volume and logarithmic viscosity of binary mixtures are nth order (1 ≤ n≤ 4) polynomialsof the mole fraction of one of the components at the system temperature,and parametric coefficients of such polynomials are mth order (1 ≤ m≤ 4) polynomials ofsystem temperatures. Parametric coefficients of fitted fourth orderRedlich–Kister type equations (RK-eq) are linear functionsof temperature. Excess properties and derived thermodynamic propertiesof both mixtures have been discussed in terms of intramolecular andintermolecular interactions of molecules. Like virial equations ofstate (EOS), dimensionless RK-eq quantifies to calculate virial coefficientsand hence to compute interactions among component 1–1, component1–2, and component 2–2. Parametric coefficients of theVogel–Fulcher–Tammann equation of viscosity are polynomialsof mole fractions of one of the components. [ABSTRACT FROM AUTHOR]

Thepresent work focused on the selective sorption of silver ions fromaqueous solutions by a thiourea-grafted mesoporous polystyrene resinand subsequent reduction of the Ag+ions to silver nanoparticles(AgNPs) embedded in the polymer matrix. The effects of various parameterssuch as pH, contact time, concentration, temperature, and presenceof competing metal ions were studied for the optimum uptake of silverions to enhance the yield of AgNPs. The most favorable sorption ofsilver ions was observed in the pH range of 1.5–1.0 and at27–30 °C. A chemical method was used for in situ reductionof the adsorbed silver ions to AgNPs on the polymer matrix. The polymer-embeddedAgNPs showed a very good bactericidal activity against Escherichiacoli. The AgNPs were separated from the polymer support byultrasonication and characterized by TEM, UV–vis spectroscopy,EDX, and XRD. The particles were of cubic phase (fcc) and were monodispersedwith a mean diameter of 8 nm. [ABSTRACT FROM AUTHOR]