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The presence of pharmaceutical compounds in the environment is problem for human health worldwide. Paracetamol is one of the pharmaceutical compounds that is widely used as a pain reliever and fever reducer, and it has been discharged in water via industrial and domestic wastewater. This study aimed to improve the removal of paracetamol from aqueous solutions using two different amino-acid-modified mesoporous silica nanoparticles (MSNs). Two types of adsorbents were used: the surfaces of epoxy-modified MSNs were modified with glycine (MSN-Gly) and cysteine (MSN-Cys). Topographical images indicated that the size of fabricated nanoparticles ranged between 220 and 360 nm, with a pore size of ~5 nm. IR spectra confirmed the successful attachment of amino acids on MSN surfaces as a peak appeared at ~1720 cm−1, indicating a carbonyl group. A series of experiments were performed using the batch adsorption method to investigate the effects of contact time, initial concentration of the adsorbate, and pH on the removal of paracetamol from the aqueous solution. The adsorption capacity of paracetamol was higher in acidic media for both adsorbents. The maximum adsorbed amount of paracetamol was 300 mg/g for MSN-Gly compared with 250 mg/g for MSN-Cys. For both adsorbents and at all pH values, the experimental data were well matched with the pseudo-second order and the adsorption isotherm was fitted using a Temkin model. [ABSTRACT FROM AUTHOR]

Methylene blue removal from aquatic environment using newly synthesized mesoporous carbon-glassy polyvinyl alcohol/silica gel composite. The mesoporous hybrid composite was characterized using several techniques, including IR, UV–Visible, TGA, surface morphological analyses images, EDX spectra and XRD. The removal method of methylene blue removal affected by factors such as increase in pH, temperature, time of adsorption, MB initial concentration and dosage of adsorbent was investigated. The elimination percentage of MB varied from 91 to 96% as the temperature increased from 293 to 323 K, respectively. The efficiency of MCPS is evident by giving a 91% removal rate for a 25 mg/L dye solution at 293 K compared to 44% for the glassy PVA/silica gel hybrid composite and 36% for mesoporous. The desorption efficiencies obtained for MCPS were 8%, 32% and 6.5% for H2O, HCl and acetic acid, respectively. The findings were processed utilizing two adsorption isotherm models in addition to kinetic models. The kinetic analysis results suggested that the pseudo-first-order model was consistent with the experimental findings. The Langmuir isotherm model was considered to be an adequate model for the uptake process. The highest capacities for uptake at 293, 303, 313 and 323 K were 13.55, 16.59, 19.81 and 25.01 mg/g, respectively. The thermodynamic parameters explained that MB removal was spontaneous and endothermic with ΔHo = 26.24 kJ/mol. From the low desorption efficiencies, we confirmed the uptake of MB by MCPS via physisorption. [ABSTRACT FROM AUTHOR]

Industrial waste consisting of dyes has emerged as a major waterbody pollutant in these modern times. Therefore, an efficient method is required to remove and address these water contaminant concerns. The current study reported the fabrication of a new hybrid type carboxylatedalginic acid (CAA) coordinated with Sn-metal (Sn-CAA) green composite absorbent for the removal of toxic dyes such as Acid Red (AR.) and Brilliant Green (BG). To obtain CAA, alginic acid was chemically oxidised via KMnO4 and it was subsequently used to coordinate with Sn2+ metal ion. The characterisation such as field emission-scanning electron microscope, X-ray powder diffraction technique and Fourier-transform-infrared spectroscopy was carried out to confirm the fabrication of CAA and Sn-CAA adsorbents. Several parameters including shaking time, pH, heating and concentration-effect were employed to conduct solid-phase extraction and UV-vis spectroscopy experiments were conducted to confirm the successful removal of toxic dyes from the aqueous media. The dye removal results established the spontaneous and endothermic nature of dye removal process as assessed through obtained thermodynamic and kinetic parameters. Furthermore, for the removal of BG and AR, the fabricated Sn-CAA-based adsorbent found to be more proficient than pristine CAA. [ABSTRACT FROM AUTHOR]

The use of mesoporous silica modified with L-arginine (Ar-MSNPs) for the removal of ionic dyes from aqueous solutions has been investigated. Several analytical techniques have been used to determine the characteristics of nanoadsorbents. The removal of crystal violet and fluorescein was performed using the batch method to investigate the effects of cultivation pH, initial concentrations of dyes, and exposure time on adsorption efficiency. The optimum adsorption of fluorescein was achieved at pH 2, whereas the optimum adsorption of crystal violet was achieved at pH 13. The equilibrium was established in both systems at 20 min at low concentrations, and approximately 30 min at high concentrations. The equilibrium adsorption data was analyzed using Langmuir and Freundlich isotherm models. The correlation coefficient (R2) values of the isotherms presented the best fit with the Langmuir isotherm. The adsorption kinetic data was fitted with the pseudo second-order model for both systems. [ABSTRACT FROM AUTHOR]

Dendritic Mesoporous Silica Nanoparticles (DMSNs) are considered superior in the adsorption of unfavorable chemical compounds and biological pollutants. Herein, we have synthesized folic acid-terminated dendritic mesoporous silica nanoparticles (FA-DMSN) for the removal of cationic dyes, methylene blue (MB), from aqueous solutions. The structural, morphological, functional, specific surface area, pore size distribution, and thermal properties of the synthesized DMSNs were identified using a scanning electron microscope (SEM), a transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), Brunauer−Emmett−Teller (BET), and Thermogravimetric Analyzer (TGA). The synthesized DMSNs exhibited a high surface area (521 m2 −1) and pore volume (1.2 cm3 g−1). In addition, it features both wide pore size and narrow distributions, which strongly affect the adsorption performance in terms of the equilibrium uptake time. Moreover, the impact of pH, contacting time, and dye's initial concentration on the removal efficiency of MB was studied. The extraction efficiency of FA-DMSN was found to be three times more effective than the bare DMSN materials. Langmuir isotherm fitted the experimental data very well with a correlation coefficient value of 0.99. According to the Langmuir model, the maximum adsorption capacity was 90.7 mg/g. Furthermore, the intra−particle diffusion model revealed a significantly fast intra-particle diffusion which can be attributed to the presence of the large pore's channels. Finally, the fast adsorption of MB molecules, reaching their equilibrium capacity within tens of seconds, as well as the low cost and ease of FA-DMSN fabrication, makes the developed material an effective adsorbent for water remediations. [ABSTRACT FROM AUTHOR]

Two-dimensional MXene-based materials are potential of presenting unique catalytic performances of electrocatalytic reactions. The surface functionalization of MXene-based catalysts is attractive for developing efficient electrocatalysts toward nitrogen reduction reaction. Herein, we reported a Ti3C2Tx MXene with a medium density of surface functionalized fluorine terminal groups, as an excellent N2 reduction reaction electrocatalyst with enhanced adsorption and activation of N2. The Ti3C2Tx MXene catalyst showed a production rate of ammonia as 2.81 × 10–5 μmol·s−1·cm−2, corresponding to a partial current density of 18.3 μA·cm−2 and a Faradic efficiency of 7.4% at − 0.7 V versus reversible hydrogen electrode in aqueous solutions at ambient conditions, substantially exceeding similar Ti3C2Tx MXene catalysts but with higher or lower densities of surface fluorine terminal groups. Our work suggests the capability of developing surface functionalization toolkit for enhancing electrochemical catalytic activities of two-dimensional MXene-based materials. [ABSTRACT FROM AUTHOR]

The development of capacitive deionization (CDI) electrode materials to improve electrochemical properties and specific capacitance (C s) has attracted considerable attention. Due to their excellent physical, chemical, electrical, and electrochemical properties, cerium oxide nanoparticles (CeO 2 NPs) have been intercalated between graphene nanoflakes (GNFs) to improve the electrosorption capacity of GNFs in CDI cells. In this study, the nanocomposite was prepared via simple sonication and hydrothermal treatment processes. The electrochemical activity of the nanocomposite was examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in an NaCl aqueous solution. Moreover, the desalination activity was performed based on a batch mode CDI technique. The studied nanocomposite demonstrated a distinct improvement in the C s and electrosorption capacity compared to those of the pristine GNFs. The studied electrode material (5% CeO 2 @GNF) showed higher cycling stability, higher specific capacitance (452.26 F/g), higher salt removal efficiency (65%), and better electrosorption capacity (7.2 mg g−1) than GNFs and 10% CeO 2 @GNFs in 100 μS cm−2 NaCl solution at 1.4 V. Overall, this study introduces a novel, efficient, and low-cost nanocomposite (CeO 2 @GNF) for the technological advancement of CDI. [ABSTRACT FROM AUTHOR]

In this article, we report the efficient removal of arsenic in the form of arsenite (As(III)) from an aqueous solution which was applied on the industrial effluents. A flat-sheet polypropylene-supported liquid membrane (SLM) was clamped between the feed phase and strip phase in a liquid membrane permeator setup using tridodecylamine (TDDA) as carrier for extraction of As(III). We have optimized the reaction in changing different parameters such as metal, acid concentration in feed phase, strip phase concentration, and carrier concentration for the maximum As(III) transport through the SLM. The flux value, time of extraction, the stoichiometry of the complex formed, and membrane stability were also investigated. As a result of different experiments performed, we find the best conditions of 0.1 mol/L of TDDA, 1.0 mol/L of HCl in feed phase at optimum pH 1, and 1.0 mol/L of NaOH in stripping phase for the maximum As(III) removal. The optimized reaction was utilized on effluent collected from different industries. During repeated set of experiments on a single polypropylene membrane, it was found that it could withstand five consecutive experiments. Moreover, as high as 93% of extraction efficiency was achieved in 180 min. [ABSTRACT FROM AUTHOR]

The self-assembly of pharmaceutical amphiphiles is an important area of research because of the involvement of these amphiphiles in physiological processes. The mixed micellization behavior of antipsychotic drug (chlorpromazine hydrochloride, CPZ) in the presence of bile salt (sodium cholate, SC) was studied by surface tension and fluorescence techniques in aqueous/urea solution. The output of the study has been analyzed by using different models (Clint, Rubingh, and Motomura) for mixed amphiphilic systems. The attractive or synergistic interactions between these two amphiphiles in water/urea were confirmed by the obtained data. Various thermodynamic parameters for the mixed micellization process have been computed and discussed. [ABSTRACT FROM AUTHOR]

In this research work, a simple method of silver nanoparticles' self-synthesis in chitosan (CH) biopolymer hydrogels without utilizing a reducing agent is shown. The synthesized material was used as a catalyst in different reduction reactions. For this purpose, different amounts of CH powder were dissolved in acidic aqueous solutions and then crosslinked it with the formaldehyde solution to make a CH biopolymer hydrogel. Among all the prepared samples, a CH hydrogel prepared from a dense solution was found to be suitable for this study because of good mechanical stability. For the self-synthesis of silver nanoparticles inside hydrogel, it was immersed in an aqueous solution of AgNO3 (10 mM) for 3 days at room temperature. The color of the chitosan hydrogel changed to brown from transparent which indicated the successful formation of silver nanoparticles on CH hydrogel (Ag-CH). No reducing agent for conversion of the Ag1+ ions to nanoparticles in this whole synthesis method. Instrumental techniques such as FESEM, XRD and EDX analysis confirmed the successful preparation of Ag-CH. The Ag-CH was checked as a catalyst in the 2-nitrophenol (2-NP) and acridine orange (ArO) reduction reactions. Both reactions were carried out at high rate constants (2-NP = 0.260 min−1, ArO = 0.253 min−1) by using the Ag-CH hydrogel catalyst. In addition, we discussed the mechanism of action of the reducing agent, the effect of kapp on the two reduction reactions of Ag-CH and the recyclability. [ABSTRACT FROM AUTHOR]

In the present article, a facile method for the self-synthesis of silver nanoparticles without the use of reducing agent in a gelatin biopolymer hydrogel and its utilization as a catalyst for the pollutants reduction reactions is demonstrated. We first synthesized different wt% of the gelatin aqueous solutions at high temperature followed by crosslinking with formaldehyde solution. Among the three different wt% of the gelatin hydrogels, we found that the 8% hydrogel was suitable for this study. The hydrogel was immersed in a 10 mM AgNO3 aqueous solution for three days, after which, the gelatin hydrogel changed its color from transparent to brown color indicating the self-formation of the silver nanoparticles inside the gelatin hydrogel (Ag-GL). Importantly, the formation of the nanoparticles did not require any reductant by using this method. The successful preparation of the Ag-GL was confirmed by FESEM, XRD, EDX and TGA analyses. The Ag-GL was tested as catalyst in the reduction reactions of the methyl orange (MO) and 4-nitrophenol (4-NP). Both of these reactions were progressed with high rate constants (kapp = 0.966 min−1 for MO and 0.621 min−1 for 4-NP were observed). In addition, we discussed the mechanism, influence of the reductant and recyclability of the Ag-GL on the kapp of the both reduction reactions. Ag nanoparticles were self-synthesized inside a gelatin biopolymer hydrogel without using the harsh chemicals, which were used as hydrogel reactor for hydrogenation of pollutants. [ABSTRACT FROM AUTHOR]

Electrospinning technique is a simple and cheap method for fabrication of electrospun nanofibers (ENFs), which in turn can converted into electrospun carbon nanofibers (ECNFs) by carbonization process. The controlling of the ECNFs properties (e.g. surface area, porosity, diameters) during fabrication, make it superior over the other carbon nanomaterials. The aim of our study is to modify the surface of ECNFs to increase its hydrophilicity and in turn its efficiency in removing lead ions (Pb2+) from aqueous systems. The surface modification was carried out in two steps starting from oxidation of pristine ECNFs to produce oxidized ECNFs (o-ECNFs), followed by covalently bonded of melamine, and poly(m-phenylene diamine) for forming melamine-functionalized ECNFs (melam-ECNFs) and poly(m-phenylene diamine)-functionalized ECNFs (PmPDA-ECNFs), respectively. The as-prepared materials were characterized in routine way. The ability of the as-prepared materials towards adsorption of Pb2+ ions as heavy metal was investigated with the study of some factors such as pH solution, contact time, initial concentration and temperature. The adsorption process was analyzed isothermally, and kinetically. According to the values of the thermodynamic parameters, the adsorption of Pb2+ ions onto the functionalized ECNFs was endothermic and spontaneous, except with melam-ECNFs was exothermic. [ABSTRACT FROM AUTHOR]

A study of the interaction of tetradecyltrimethylammonium bromide (TTAB) and levofloxacin hemihydrate (LFH) mixtures has been studied by conductivity measurement method in aqueous medium and in the presence of inorganic electrolyte (KNO3 and K2SO4)/urea at various temperatures (298.15−318.15 K) with typical gap of 5 K. For pure TTAB along with drug–TTAB mixture in aqueous as well as in salts/urea solution, a single critical micelle concentration (CMC) was noticed. The CMC values for LFH-TTAB mixtures in the presence of salts exhibited lower in magnitude as compared to aqueous solution. The ΔGm values were found to be negative in the entire cases signifying the spontaneous formation of micelles. Both ΔHm and ΔSm indicated that hydrophobic as well as electrostatic interactions were enhanced in the presence of electrolytes compared to an aqueous solution. Other thermodynamics variables such as transfer enthalpy (ΔHm.tr), transfer energy (ΔGm.tr), and transfer entropy (ΔS°m.tr) were evaluated and explained thoroughly. [ABSTRACT FROM AUTHOR]

Cloud point (CP) measurements of 4‐(1,1,3,3‐tetramethylbutyl) phenyl‐polyethyleneglycol (Triton X‐100 (TX‐100)) were performed in aqueous solution in the presence of drug Amikacin sulfate (AS)/Neomycin sulfate (NS)/(AS/NS+ different inorganic salts). In aqueous solution, the CP values of TX‐100 first decrease with increasing concentration and then increase with increasing surfactant concentration. The CP values of TX‐100 solutions were found to increase with the increasing concentration of the AS/NS drug. The CP values of TX‐100‐AS/NS mixtures were also observed to decrease with the increase of the concentration of salt. Different thermodynamic parameters such as standard free energy (ΔGc0), standard enthalpy (ΔHc0) as well as the standard entropy (ΔSc0) change of phase separation were calculated and discussed in relation to molecular interactions. [ABSTRACT FROM AUTHOR]

Abstract Here, different loading of palladium (Pd), ranged from 0.5 to 5 wt%, was incorporated into the three dimensional siliceous mesoporous material; TUD-1. The synthesis procedure was carried out without the use of solvents, surfactants, and/or copolymers. Only triethanolamine and water with the precursors of Si and Pd were applied in one-pot synthesis procedure to prepare Pd-TUD-1 materials. The prepared materials were characterized by means of elemental analysis, XRD, Raman spectroscopy, N 2 sorption measurements, SEM and TEM. Characterization data confirmed the formation of PdO particles inside the pores of TUD-1 matrix, moreover bulky PdO particles were also detected as an extra-framework separated phase in the high loading samples. The prepared samples were divided into two batches, the first was activated by hydrogenation at 300 °C for 3 h, and the second batch did not activated. The catalytic activity of the two batches was examined in the selective hydrogenation of 1,5-cyclooctadiene (COD) at 80 °C under solvent-free condition to produce cyclooctene (COE). The obtained results showed that the samples of the two batches were able to catalyze the reaction with a very comparable activity. The non-hydrogenated sample with a 0.5% Pd gave 98.5% COD conversion with a COE selectivity of 92.8%, while the same sample which pre-hydrogenated gave 96.8% of COD conversion and 93.5% selectivity towards COE. The characterization of the used catalysts confirmed that PdO was in-situ reduced to Pd nanoparticles during the reaction. Graphical abstract Image 1 Highlights • PdO nanoparticles were incorporated with different loading in TUD-1 mesoporous material. • Pre-activation of PdO nanoparticles was performed by hydrogenation to generate Pd0 active sites. • The reduction of 1,5-cyclooctaniene was used to evaluate the catalytic activity of the pre-activated catalysts and the as-synthesized ones. • The activity data shows that the pre-activation (hydrogenation) step is not necessary at low Pd loading. [ABSTRACT FROM AUTHOR]

Herein, we have studied the interaction between cationic surfactant (conventional [myristyltrimethylammonium bromide, MTAB] as well as gemini surfactant 1, 4-butanediyl-α, ω-bis(dimethyltetradecylammonium bromide) (14-4-14)) and anti-inflammatory sodium salt of ibuprofen (IBU) drug in aqueous solutions by using tensiometry method at 298.15 K. The means of the interaction of drugs by added foreign materials is of paramount importance in the drug delivery. Ibuprofen is used for the relief of pain, fever, and swelling. From this study we have evaluated different parameters, for example, critical micelle concentration ( cmc), micellar mole fraction of mixed micelles/mixed interface ( X1m/ X1σ), micellar/surface interaction parameter ( βm/ βσ), activity coefficients ( f1m/ f1σ and f2m/ f2σ) of the mixed micelles/mixed interface, excess Gibbs free energy of mixed monolayer/mixed micelle formation ( [ABSTRACT FROM AUTHOR]

This paper deals with a comprehensive study of the mixed micellization and adsorption behavior of mixed systems enclosing an amphiphilic antidepressant drug nortriptyline hydrochloride (NOT) and Triton X-114 (TX-114) (nonionic surfactant) in aqueous/urea (500 mmol·kg−1 and 1000 mmol·kg−1) solutions by tensiometric method. The NOT is used for the cure of depression. For comparison purpose cmc value of pure drug NOT was also evaluated by conductimetric technique. Different theoretical models like Clint, Rubingh, and Rosen were used to get information about the nature of interaction between the components in bulk and at the interface. Because of the occurrence of urea increase in the surface charge of the micelles was obtained resulting a delay of the micelles formation. The cmc values of the mixed systems of NOT and TX-114 were found to be in between the cmc values of pure components, which signify nonideal mixed system having attractive interactions in the absence and presence of urea. Various parameters such as micellar mole fractions of TX-114 ( X1m, X1σ) in solution and at interface, interaction parameter ( βm/ βσ) in solution and at interface, and activity coefficient in solution and at interface were evaluated and discussed using Rubingh's and Rosen's models. Surface excess ( Γmax) increases that means minimum area per head group ( Amin) decreases as mole fraction ( α1) of TX-114 increases in the absence/presence of urea. Different thermodynamic parameters have been calculated and discussed. The ∆ G0m values achieved are all negative both in the absence and occurrence of urea. [ABSTRACT FROM AUTHOR]

Herein, the interactions between the sodium salt of ibuprofen (IBU) with nonionic surfactant-BRIJ-56 were investigated at the interface as well as in the bulk phase (solution) in the existence and nonexistence of urea (250 mM). In the present study, tensiometric and fluorometric techniques have been utilized to investigate the association and micro-environmental properties of mixed systems. Various models (such as Clint, Rubingh, Maeda, etc.) were employed to obtain information regarding the nature of interaction between the components in bulk as well as at the interface. The critical micelle concentration (cmc) of pure amphiphiles and their mixed system increases in the existence of urea due to enhancement in the surface charge of the micelles. The urea activities have been explored on account of diverse aspects, such as the salvation of head groups and hydrophobic interactions. The aggregation number, micropolarity, and apparent dielectric constant of pure and mixed systems were investigated using steady-state fluorescence spectroscopy. A variety of energetic parameters (for instance the standard Gibbs free energy of micellization, Gibbs free energy of adsorption, and Gibbs excess energy) have been evaluated for further insight of urea action. The Δvalues achieved are all negative, both in the absence and in the presence of urea. [ABSTRACT FROM AUTHOR]

Photodegradation of phenol in the presence of tin dioxide (SnO 2 ) nanoparticles under UV light irradiation is known to be an effective photocatalytic process. However, phenol degradation under solar light is less effective due to the large band gap of SnO 2 . In this study antimony (Sb) doped tin dioxide (SnO 2 ) nanoparticles were prepared at a low temperature (80 °C) by a sol–gel method and studied for its photocatalytic activity with phenol as a test contaminant. The catalytic degradation of phenol in aqueous media was studied using high performance liquid chromatography and total organic carbon measurements. The change in the concentration of phenol affects the pH of the solution due to the by-products formed during the photo-oxidation of phenol. The photoactivity of SnO 2 :Sb was found to be a maximum for 0.6 wt.% Sb doped SnO 2 nanoparticles with 10 mg L −1 phenol in water. Within 2 h of photodegradation, more than 95% of phenol could be removed under solar light irradiation. [ABSTRACT FROM AUTHOR]

Herein, we have examined the interaction between promazine hydrochloride (PMZ) with bile salts (sodium cholate (NaC) and sodium deoxycholate (NaDC)) at different temperatures and compositions using conductometric method. The critical micelle concentration (cmc) value of pure PMZ and bile salts were also evaluated by tensiometric method. Thecmcvalues attained by the two methods are close to each other. Various physicochemical parameters likecmc, idealcmc(cmcid), degree of dissociation of counterion (g), micellar mole fractions of bile salt (,,), micellar mole fraction of bile salt in ideal state (), interaction parameter (βm), activity coefficients (f1,f2), standard Gibbs free energy (), enthalpy (), entropy of micellization (), and excess free energy of mixing (ΔGex) of the mixed micelles have been evaluated and discussed in detail using Clint's, Rubingh's, Motomura's, and Rodenas's models. NaDC is more efficient in decreasing thecmcof PMZ as compared to NaC because it binds strongly to PMZ ions and more decreases the head group area of drug. On the whole, this lesson might find application in the fundamental science of the physical chemistry of amphiphilic systems, as well as in the research of drug delivery system. [ABSTRACT FROM PUBLISHER]

A novel aqueous-based, single-source precursor (SSP) method for the synthesis of pure, room temperature-stable, nanocrystalline β-NiMoO 4 with controlled composition was developed. The soft – chemical nature of the synthesis approach and the crystal structure features of the bimetallic hydroxyisobutyrate precursor were found to play an essential role in the fabrication of the target metastable oxide under mild synthetic conditions. [ABSTRACT FROM AUTHOR]

L-glutamic acid is used in the production of monosodium glutamate spices and other biochemical reagents. Its oxidation kinetics and a detailed mechanistic interaction of Os(VIII) catalyzed Glue-CAT reaction in alkaline medium have been investigated at different temperatures. It has been studied spectrophotometrically as a basic experimental approach for this study. All variables affecting the development of the color were investigated and the conditions were optimized. The effect of Glue, CAT, Os(VIII), and OH concentration on the rate of reaction has been studied. The reactions follow identical kinetics for all It is a first order reaction in both Glue and CAT, but fractional order in alkali and Os(VIII). Increasing ionic strength dielectric constant of the medium had no significant effect on the rate. The effects of added products like halide ions and toluene-p-sulfonamide have also been investigated. A mechanism involving the formation of a complex between Glue-CAT-Os(VIII) has been proposed. The stoichiometry of the reaction is found to be 1:1. The main products of Glue were identified with the help of FTIR and TLC. The reaction constants involved in the mechanism are explained. There is a good agreement between the observed and calculated rate constants under different experimental conditions. Investigations at different temperatures allowed the determination of the activation parameters with respect to the slow step of the proposed mechanism. The proposed methods were successfully applied for the high yield of the products and short reaction times. It is also an inexpensive, simple, and smooth method. [ABSTRACT FROM AUTHOR]

A mechanistic approach to the influence of Mn(II) catalyzed oxidative deamination of an anti-convulsant drug [GP] by peroxomonosulphate (PMS) at a constant ionic strength of 1.0 mol dm -3 have been studied, spectrophotometrically. The reaction shows first order dependence on [PMS] and [Mn(II)] and apparent less than unit order dependence each in [GP] and alkali concentrations. Influence of dielectric constant and ionic strength of the medium on the reaction rate have been evaluated. It was observed that the added sulphate ion, the reduction product of the oxidant, had insignificant effect on the reaction rate. The reaction stoichiometry and oxidation products deprotonated GP, SO4 2− and MnO2 have been identified and a suitable mechanism has been proposed. The reaction fails to initiate polymerization in the presence of acrylonitrile under the experimental conditions employed. In a composite equilibrium step, deprotanated GP binds to catalyst and form a complex C that subsequently decomposes with oxidant to yield the products. Investigations of the reaction at different temperatures allowed the determination of the activation parameters and a tentative reaction mechanism in good consistency with the kinetic results is discussed. [ABSTRACT FROM AUTHOR]

A novel poly(amino acid methacrylate) brush comprising zwitterionic cysteine groups (PCysMA) was utilized as a support for lipid bilayers. The polymer brush provides a 12-nm-thick cushion between the underlying hard support and the aqueous phase. At neutral pH, the zeta potential of the PCysMA brush was ∼−10 mV. Cationic vesicles containing <25% DOTAP were found to form a homogeneous lipid bilayer, as determined by a combination of surface analytical techniques. The lipid mobility as measured by FRAP (fluorescence recovery after photobleaching) gave diffusion coefficients of ∼1.5 μm² s–1, which are comparable to those observed for lipid bilayers on glass substrates. [ABSTRACT FROM AUTHOR]

Highlights: [•] Selective detection of La(III) ions based on doped SnO2–TiO2 nanocomposites. [•] SnO2–TiO2 NCs used as a selective solid phase adsorbent. [•] The static adsorption capacity for Au(III) was calculated to be ∼65.60mg/g. [•] Adsorption process was mainly monolayer based onto a surface containing a finite number of adsorption sites. [Copyright &y& Elsevier]

Highlights: [•] A PAMAM light-harvesting dendron of second generation, core and peripherally functionalized with Rhodamine 6G and 1,8-naphthalimide fluorophores is synthesized. [•] The yellow-green emitting periphery of the antenna is designed as a PET based fluorescence probe. [•] The system manifests excellent selective response to protons over representative metal ions in aqueous medium. [•] Core emission intensity of the systems is enhanced by over an order of magnitude as a function of pH. [•] The wavelength-shifting bichromophoric system acts as a highly selective ratiometric fluorescent pH probe in complex samples. [ABSTRACT FROM AUTHOR]

Co3O4 co-doped TiO2 nanoparticles were prepared by a low temperature thermal method and their functional relationships with metal ions was investigated using solid phase extraction. The analytical potential of Co3O4 co-doped TiO2 nanoparticles was studied for the selective extraction of lead using inductively coupled plasma-optical emission spectrometry. The selectivity of Co3O4 co-doped TiO2 nanoparticles was investigated toward different metal ions, including Cd(ii), Co(ii), Cr(iii), Cu(ii), Fe(ii and iii), Hg(ii), La(iii), Mn(ii), Ni(ii), Pb(ii), Pd(ii) and Y(iii). Data obtained from the selectivity study showed that Co3O4 co-doped TiO2 nanoparticles have the highest selectivity toward Pb(ii). The uptake capacity for Pb(ii) was experimentally calculated to be 114.05 mg g−1. Moreover, adsorption isotherm data of Pb(ii) on Co3O4 co-doped TiO2 nanoparticles fit well with the Langmuir adsorption isotherm, strongly supporting that the adsorption process was mainly as a monolayer on Co3O4 co-doped TiO2 nanoparticle surfaces. [ABSTRACT FROM AUTHOR]

The mechanistic investigation of oxidation of levofloxacin(LF) has been studied by chloramine-T(CAT) in aqueous perchloric acidmedium at 25 °C. The reaction followed first-order kinetics withrespect to [CAT], [LF], and [H] in their lower concentrationsrange, tending to zero-order at their higher concentrations. First-orderkinetics with respect to [CAT] was observed for the oxidation of levofloxacin.An increase in perchloric acid concentration increased the rate ofreaction. The effect of added products, ionic strength, and dielectricconstant of the medium was studied on the rate of reaction. The mainproducts were identified by spot test, FT-IR, and NMR. A mechanismwas proposed on the basis of experimental results. The activationparameters with respect to the slow step of the mechanism was evaluated,and the thermodynamic parameters were also determined and discussed. [ABSTRACT FROM AUTHOR]

Bile salts are steroidal surfactants consisting of 2 to 12 monomers to form a micelle. The most important physiological property of bile salts is the solubilization of cholesterol. The bile salts make mixed micelle with phospholipids that enhance the bile salts ability to solubilize cholesterol. The mixed micelle formation in aqueous solution between two bile salts (sodium taurocholate [NaTC] and sodium deoxycholate [NaDC]) mixtures has been studied by tensiometric and fluorometric studies. The nonideal mixing behavior was examined for mixed systems, and synergism was found for the current mixed systems. Rubingh and Rosen models were used to analyze the bile salt‐bile salt binary mixtures, and the interaction parameters, as well as mixed micelle compositions at bulk and interface, have been computed as well as discussed one by one. The values of ∆Gmo were achieved to be negative for all studied systems. In the solution mixtures, as the content of NaTC increases, the formation of micelles becomes slightly less favorable. [ABSTRACT FROM AUTHOR]

This study describes an effective method developed for the removal of hexavalent chromium, Cr(VI), from an aqueous environment. In this study, the Ni– SiO 2 nanomaterial was synthesized by the sol–gel method and then characterized by field emission scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. The prepared nanomaterial was then employed as an adsorbent with significant properties of high surface area and uptake capacity. Adsorption conditions of Cr(VI) onto the Ni– SiO 2 nanomaterial were optimized by altering different parameters (pH, initial Cr(VI) concentration and different periods of time). An amount of 100.75 mg g - 1 was estimated as the maximum uptake capacity of the Ni– SiO 2 nanomaterial at pH 4.0. The experimental data of Cr(VI) adsorption onto the Ni– SiO 2 nanomaterial were fitted well to the Langmuir isotherm and pseudo second-order kinetic models. Moreover, the adsorption of Cr(VI) onto the Ni– SiO 2 nanomaterial was not influenced even in the presence of different coexisting ions. Finally, the recommended methodology was applied on several environmental water samples. [ABSTRACT FROM AUTHOR]

Abstract Rb-promoted nanocrystalline Co 3 O 4 -CeO 2 catalysts were prepared by the impregnation of the Co 3 O 4 -CeO 2 , previously prepared using the solution combustion route, with an aqueous solution of Rb 2 CO 3 (Rb/Co ratios 0.0125–0.20) and subsequent calcination at 500 °C. The obtained catalysts and the un-promoted Co 3 O 4 and Co 3 O 4 -CeO 2 catalysts have been characterized using XRD, FT-IR, SEM, TEM, XPS, H 2 -TPR and N 2 physisorption techniques. The activity of the various catalysts was tested for N 2 O direct decomposition. All the Rb-promoted catalysts exhibited better performance than the bare Co 3 O 4 -CeO 2 catalyst, where the highest activity was obtained using the catalyst with Rb/Co ratio of 0.025. The activity performance of the various catalysts was discussed in terms of the electronic properties modification accompanying the Rb-doping. For the optimum catalyst, further experiments were conducted in the presence of O 2 and NO in the reactor feed. Graphical abstract Unlabelled Image Highlights • Rb-promoted Co 3 O 4 -CeO 2 catalysts were prepared by the impregnation method. • The doping of Rb-ions into Co 3 O 4 -CeO 2 has led to morphological and textural modifications. • The catalyst with Rb/Co ratio of 0.025 exhibited the optimum activity for N 2 O direct decomposition. [ABSTRACT FROM AUTHOR]

With the intention to explore bile salts applications as drug delivery vehicles, the mixed interfacial as well as micellar behavior of the sodium salt of ibuprofen (NaIbuF) and bile salts mixtures in aqueous/electrolyte solutions has been evaluated by tensiometric method at 298.15 K. Bile salts (sodium cholate (NaC) and sodium deoxycholate (NaDC)) used in the present study are anionic in nature and form small micelles. Various theoretical models such as Clint, Rubingh, and Rosen were utilized to acquire information concerning the nature of interaction among the components in the solution as well as at the interface. Because of the presence of inorganic salt (100 mmol·kg-1 NaCl) a decrease in the surface charge of the micelles takes place and ensuing micellization occurs at poorer concentration. The value of the micellar mole fraction (X1m) is found to be greater for NaIbuF + NaDC mixtures in comparison to NaIbuF + NaC mixtures, signifying that participation of NaDC is greater in mixed micelles as compared to NaC. An attractive interaction was obtained in the micelle and at the interface, because it is obvious from interaction parameters (βm, βσ). The values of ΔG0m for all systems was negative in the absence as well as in the occurrence of salt. Micelle aggregation number (Nagg), estimated by means of steady-state fluorescence quenching studies, suggests that the contribution of bile salts was always greater than that of the NaIbuF. The micropolarity (I1/I3), Stern–Volmer binding constants (Ksv), and dielectric constant (Dexp) of mixtures also supported the synergistic behavior of the drug–bile salts mixed systems. [ABSTRACT FROM AUTHOR]

The interaction of amphiphilic antidepressant drug nortriptyline hydrochloride (NOT) with nonionic surfactant Triton X-100 (TX-100) was studied in this work using tensiometry in aqueous and in urea (500 mmol ∙ kg − 1 and 1000 mmol ∙ kg − 1 ) solutions at 303.15 K. Various models such as Clint, Rubingh, and Rosen etc. were employed to get the information regarding the nature of interaction between the compounds in bulk and at the interface. The CMC values of the mixed systems of NOT and TX-100 were found to be in between the CMC value of pure components, which suggest nonideal mixed system having attractive interactions in the absence and presence of urea. Enhancement in the surface charge of the micelles was obtained in the company of urea followed by halt of the micelles formation. Various physicochemical parameters, such as, micellar mole fraction ( X 1 Rub ) of TX-100, interaction parameters ( β σ , β m ) at monolayer air–water interface as well as in bulk solutions, thermodynamic parameters, activity coefficients ( f 1 m , f 2 m ), surface pressure at the CMC (π CMC ), for the TX-100 and NOT in the mixed micelles were determined as discussed in detail. Thermodynamic parameters (minimum energy of surface ( G min ), standard Gibbs energy of adsorption (Δ G ads ∘ ), free energy of micellization (Δ G ° m ), excess Gibbs energy of the mixed monolayer (Δ G ex σ ), excess Gibbs energy of the micelle formation (Δ G ex m ) and free energy of micellization (Δ G Maeda 0 ) (calculated by Maeda model)) and surface properties exposed that the addition of urea changes the relevant physicochemical properties which influence the process of micellization. [ABSTRACT FROM AUTHOR]

The surface and micellization behavior of binary and ternary mixtures of cetylpyridinium chloride (CPC), sodium dodecyl sulfate (SDS) and polyethylene glycol hexadecyl ether (BRIJ-56) in different mole fractions have been studied in detail by surface tension measurement. The critical micelle concentration (CMC), activity coefficients, mutual interaction parameters, interfacial adsorption, minimum area per molecule, and energetic parameters for binary and ternary systems have been determined. Here we used the Clint, Rubingh and Rubingh–Holland models to analyze the results. [ABSTRACT FROM AUTHOR]

In this manuscript, we report a facile and environmental friendly procedure for the aqueous synthesis of gold nanoparticles (∼3–8 nm) and functionalized multiwalled carbon nanotubes (MWCNT) interlinked through bi-functionalized silicate molecule N -[3(trimethoxysilyl)propyl]ethylenediamine (EDAS). The complexes, denoted by MWCNT–EDAS–AuNPs, were then characterized by UV–visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscope (TEM), and atomic force microscope (AFM). In addition, it is also fabricated on glassy carbon electrodes to simultaneously detect ascorbic acid (AA) and dopamine (DA) using an electrochemical technique. MWCNT–EDAS–AuNPs can act as a modified electrode and show a wide linear response for AA and DA in the concentration range of 1 × 10 −7 –9 × 10 −6 M and 1 × 10 −7 –8 × 10 −6 M with detection limits of 0.07 and 0.08 μM at S / N = 3, respectively. These results have demonstrated that MWCNT–EDAS–AuNPs are a promising candidate as advanced electrode material in electrochemical sensing of AA and DA simultaneously in pharmaceutical samples. [ABSTRACT FROM AUTHOR]

Abstract: The surface and mixed micellization properties of the aqueous binary mixed system of alkanediyl-α, ω-type cationic gemini surfactant, 14–4–14 and conventional nonionic surfactant, Brij-58 in an aqueous medium have been investigated over the entire mole fractions at 298.15K. The critical micelle concentration (cmc) for each mixture have been measured by tensiometric and fluorescence measurements. The solution and adsorption characteristics like composition, activity coefficients and mutual interaction parameters have been computed using different proposed theoretical models like Clint, Rosen, Rubingh, Motomura and Maeda. The strength of interaction of the surfactant is attributed to the sterical and electrical factors on mixed monolayer and micelle formation and of surfactant–surfactant interactions. The micellar aggregation number (N agg) has also been measured using steady state fluorescence quenching method at a total concentration of ~1mM of pure components as well as their mixtures of different ratios. The micropolarity and binding constant were determined from the ratio of intensity (I 1/I 3) of peaks of pyrene fluorescence emission spectrum. [Copyright &y& Elsevier]

The efficient adsorption and activation of inert N 2 molecules on a heterogeneous electrocatalyst surface are critical toward electrochemical N 2 fixation. Inspired by the bimetallic sites in nitrogenase, herein, we developed a bi-metallic tin-titanium (Sn–Ti) structure in Sn-doped anatase TiO 2 via an oxygen vacancy induced engineering approach. Density functional theory (DFT) calculations indicated that Sn atoms were introduced in the oxygen vacancy sites in anatase TiO 2 (1 0 1) to form Sn–Ti bonds. These Sn–Ti bonds provided both strong σ -electron accepting and strong π -electron donating capabilities, thus serving as both N 2 adsorption and catalytic N 2 reduction sites. In 0.1 M KOH aqueous solution, the Sn-TiO 2 electrocatalyst achieved a NH 3 production rate of 10.5 μg h−1 cm−2 and a corresponding Faradaic efficiency (FE NH3) of 8.36% at −0.45 V vs. reversible hydrogen electrode (RHE). Our work suggests the potential of atomic-scale designing and constructing bimetallic active sites for efficient electrocatalytic N 2 fixation. [ABSTRACT FROM AUTHOR]

The electrochemical nitrogen reduction reaction (NRR) under mild conditions is significantly challenging, due to the extremely high stability of dinitrogen (N 2) molecules. The NRR pathway also confronts the competitive water reduction reaction that takes places universally in an aqueous solution. Herein, a Fe 2 O 3 /Cu catalyst is demonstrated as an efficient NRR electrocatalyst. The electronic interactions elevate the d -state electron center, enabling strong back-bonding for N 2 molecules. The altering of d -electron distribution promotes the adsorption of N 2 , leading to a high catalytic activity. As a result, the Fe 2 O 3 /Cu catalyst exhibits an outstanding ammonia production rate of 15.66 μg·h−1·mg cat. −1 at −0.1 V versus reversible hydrogen electrode (RHE), a Faradaic efficiency of 24.4%, and a good electrochemical stability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Bifunctional nanocomposite with magnetic and fluorescence property was synthesized. • The nanocomposite consists of fluorescent carbon dots and magnetic MnFe 2 O 4. • The fluorescence indicates the efficient adsorption of U(VI) on the nanocomposite. • The adsorption capacity increases by two times than the single magnetic MnFe 2 O 4. Abstract Magnetic nanomaterials are promising adsorbents for their superior performance in the elimination of radioactive ions from aqueous solution. In this study, a new kind of fluorescent carbon dots were successfully introduced into MnFe 2 O 4 to fabricate magnetic polyethyleneimine-functionalized carbon quantum dots/MnFe 2 O 4 (PECQDs/MnFe 2 O 4) nanocomposites by a simple hydrothermal method, which combined the fluorescent characteristic of CQDs, adsorption capacity of polyethyleneimine and magnetic separation property of MnFe 2 O 4. Detailed characterization certified the formation of nanohybrid composites and its integrating advantages of fluorescence property and magnetism separation, which demonstrated its potential in immobilizing U(VI) and monitoring the adsorption process simultaneously in wastewater. The obtained PECQDs/MnFe 2 O 4 was applied to remove U(VI) from aqueous solution and showed superior construction stability and adsorption capacity of 194 mg/g. Moreover, the kinetic and thermodynamic results suggested that the immobilization of U(VI) was an endothermic and spontaneous multilayer adsorption dominated process. In the end, the cation exchange and interaction between uranyl ions and abundant functional groups (i.e., NH 2 , OH and COOH) on PECQDs/MnFe 2 O 4 were revealed to be responsible for the enhanced adsorption of U(VI), which was realized by forming outer-sphere surface complexes in the removal process. This study proposed an ultrafast-kinetics and high-efficiency adsorbent for U(VI) sequestration, which has a great application potential due to its outstanding recycling performance. [ABSTRACT FROM AUTHOR]

Novel polyphenylsulfone (PPSU)/nano tin oxide (SnO 2) mixed matrix hollow fiber membranes (HFMs) were fabricated by dry-wet spinning via phase separation method. In the current research, reported the contrast between neat PPSU membrane and nanocomposite membranes (PPSU/SnO 2), to determine the toxic reactive dyes namely, reactive black-5 (RB-5) and reactive orange-16 (RO-16) removal ability from the aqueous media. Scanning electron microscopy (SEM) was used to observe the HFMs cross-sectional morphological changes and surface roughness parameters of membranes were analyzed using atomic force microscopy (AFM). The surface wettability ability of HFMs was examined with a contact angle, water uptake, and porosity measurements. The cross-flow filter unit was engaged to quantify the water permeability, anti-fouling ability as well as the dye rejection ability of fabricated membranes. With increasing the SnO 2 NPs wt% in PPSU polymer matrix the membrane performance was enhanced continuously, it became evident that the incorporated SnO 2 NPs plays main role in membrane performance. Added, water-soluble poly (vinylpyrrolidone) (PVP) can also impact the pore morphology in membranes. At the end, PS-3 membrane exhibited lower contact angle (63.7 0), higher water uptake (74.8%), porosity (84.1%), pure water flux 362.9 L/m2 h, and high potential for dyes rejection application, of about >94% for RB-5, and >73% for RO-16 dye, respectively. From the preliminary results, it can be stated that the usage of SnO 2 NPs in membrane technology become effective towards wastewater treatment. Unlabelled Image • Novel PPSU/nano SnO 2 mixed hollow fiber membranes were fabricated by dry-wet spinning via phase separation process. • The cross-flow filter unit was engaged to check the permeability and rejection efficacy of the membranes. • The nanocomposite membranes showed better outcomes. • The PS-3 membrane displayed dyes rejection above 94% and 73% for RB-5 and RO-16 dyes, respectively. [ABSTRACT FROM AUTHOR]

Abstract Wastewater containing heavy metal ions such as lead should be treated for cleanup before discharge to environment. This work reports new nanomaterials of orthohexagonal iron oxide for efficient removal of lead (II), which were doped with cobalt (Co Fe 2 O 3) or Nickel (Ni Fe 2 O 3) ions through a simple method. The structure of adsorbents and adsorption mechanism were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometer, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy and so on. The results showed that the concentration of nitrate concentration has a tiny effect on the Pb(II) adsorption and the kinetic adsorption experiments showed that Co Fe 2 O 3 and Ni Fe 2 O 3 took less time to achieve the equilibrium state than Fe 2 O 3 without doping And the isotherm batch experiments showed that Langmuir model matched well with the data of Fe 2 O 3 , Freundlich model fitted well in Co Fe 2 O 3 and Ni Fe 2 O 3 experiments data, indicating that cobalt/nickel doping changes the adsorption mechanism. XPS analysis showed that the hydroxyl at surface played an important role in Pb(II) removal and the hydrogen bond was replaced by metal-oxygen bond. Furthermore, the adsorption capacities of, Co Fe 2 O 3 and Ni Fe 2 O 3 for Pb(II) removal were 136.0 mg/g and 97.5 mg/g respectively, which were superior to pristine Fe 2 O 3 (93.9 mg/g). This study clearly showed that Co Fe 2 O 3 and Ni Fe 2 O 3 are promising candidates for lead ion removal in aqueous solution. Graphical abstract Image Highlights • Ortho-hexagonal iron oxides at nanometer scale have been synthesized through a cost-effective simple method. • The crystal structure of α-Fe 2 O 3 was transformed into γ-Fe 2 O 3 by doping with cobalt or nickel. • The doping with cobalt greatly enhanced the adsorption capacity of the iron oxides. • The adsorption mechanism of lead on the materials was extensively studied. [ABSTRACT FROM AUTHOR]

Abstract In order to investigate the immobilization ways of uranium (U(VI)) on Kocuria sp., we investigated the interaction behavior under different conditions by batch experiment. U(VI) products on Kocuria sp. were characterized by SEM, XRD, FTIR, and XPS techniques. SEM-EDS results presented U(VI) mineral-like precipitation formed on the cell surface which contained high percentage of P and U elements. XPS results also confirmed the appearance of bond P-O-U. XRD results illustrated characteristic UO 2 2+ peaks after U(VI) interaction with Kocuria sp. According to FTIR analysis, in addition to PO 4 3− groups, C O, OH, COOH groups might play important roles in complexation with U(VI). The biomineralization process of U(VI) on Kocuria sp. required longer time than sorption process, indicating that biomineralization was induced by the biosorption process. Our findings highlight the synergistic biosorption and biomineralization process of Kocuria sp. for U(VI) immobilization, which concentrated U(VI) on the cell surface via fast biosorption by providing nucleation sites for the precipitation to insoluble minerals, while the formation of U(VI) biomineral led to the relatively permanent immobilization of U(VI), and then emphasize the important roles of phosphate which are of significance in predicting the U(VI) immobilization properties. Graphical abstract Unlabelled Image Highlights • Effective U(VI) removal by Kocuria sp. • Fast biosorption provides nucleation sites for the precipitation to uranium biominerals. • PO 4 3− groups play an important role in biomineralization of U(VI). [ABSTRACT FROM AUTHOR]

Contamination of heavy metal (Cd2+ & Pb2+) ions in drinking water is producing major impacts on the environment and public health and is considered one of the greatest dangers to humanity. Membrane technology has been chosen over other processing methods due to its simplicity and high capacity for more effective removal of hazardous heavy metals. In the current study, amine, thiol, and bi-thiol functional groups were used to functionalize mesoporous silica nanoparticles (MSNs) to improve the efficiency of the silica nanoparticle. The morphology of the MSNs as well as the existence of amine and thiol on the surface of MSNs was demonstrated by a variety of characterization techniques, including FTIR, TEM, and SEM examination. The impact of surface-modified MSNs on the morphology, properties, and performance of polysulfone (PS) nanofiltration (NF) membranes was also evaluated. The membrane that incorporated amine with thiol-based MSNs (DiMP-MSNs/PS-NF membrane) had the highest pure water permeability (6.7 LMH bar−1). As a result of the functional groups, the surface-modified MSNs/PS nanofiltration are extremely effective at removing heavy metal ions from aqueous solutions. The surface-modified MSNs/PS nano-filtration membranes exhibit unprecedented Cd2+ and Pb2+ removal rates of approximately 82% and 99%, respectively. This research indicates the possible application of the surface-modified MSNs/PS nanofiltration membrane as a promising platform to remove heavy metal ions from polluted water. [ABSTRACT FROM AUTHOR]

Aggregation behavior of sodium salt of ibuprofen (SIBU) and conventional surfactant - hexadecyltrimethylammonium bromide (HTAB) along with gemini surfactant - 1,6-Bis( N -hexadecyl- N , N -dimethylammonium)hexane dibromide (16-6-16) mixtures have been carried out at 298.15 K by employing tensiometric method. Different hypothetical models for instance, Clint, Rubingh, as well as, Rosen was engaged to obtain the nature of interaction amid the drug and surfactant in the solution and at the interface. Gemini surfactant is more effective in decreasing the critical micelle concentration ( cmc ) of the drug as compared to conventional surfactant. The mixed systems show lower cmc value in comparison to ideal cmc ( cmc id ) value representing the non-ideal behavior of present solution mixture of drug and surfactant. The nonideality of the mixed system also stated in terms of the interaction parameter ( β m / β σ ). Additional parameters concerning tensiometry methods, for instance, micellar mole fraction of mixed micelles/mixed interface ( X 1 m / X 1 σ ), area occupied per amphiphile molecule ( A min ), surface excess concentration ( Γ max ), etc. were computed and discussed one by one. Packing parameters were also evaluated and discussed. The Δ G o m and Δ G o ads values for every studied solution were achieved to be negative i.e., micellization, as well as adsorption processes, are energetically favorable and the value of Δ G o ads were more negative than their corresponding Δ G o m , showing that work is done in transferring the amphiphilic monomers from interface to the micellar stage across the aqueous solution to form micelles. [ABSTRACT FROM AUTHOR]

A novel nanocomposite, i.e., molybdenum disulfide nanosheets embellished nanoiron (MoS 2 /NZVI), was synthesized by a modified NaBH 4 reduction procedure, and used for the effective capture of Cr(VI) in water. The characteristic analysis implied that MoS 2 could hinder the aggregation of NZVI. The batch experiments showed that Cr(VI) capture by NZVI/MoS 2 (91.7%) was obviously higher than that of either bare NZVI (62.6%) or MoS 2 (27.05%). The kinetics of Cr(VI) capture can be well described by the pseudo-second-order model. The effects of pH and natural organic matters were also evaluated. Solution pH was found to be significant to Cr(VI) capture, acidic environment (pH 5.0 and 6.0) was more suitable for Cr(VI) capture. However, natural organic matters demonstrated negative effects on Cr(VI) capture. The capture capacity of NZVI/MoS 2 nanocomposite decreased from 126.42 mg/g to 118.48 and 121.07 mg/g when humic acid and fumic acid were present in the solution. X-ray photoelectron spectroscopy analysis of the mechanism indicated that adsorption, reduction, and precipitation were involved in the capture process. The results suggested that the NZVI/MoS 2 nanocomposite may be a potential candidate for the capture of Cr(VI) from wastewater. [ABSTRACT FROM AUTHOR]

Interaction of anionic bile salt sodium taurocholate (NaTaC) and anionic anti-inflammatory drug sodium salt of ibuprofen (NaIBU) in aqueous solutions together with in occurrence of 100 mmmol kg −1 NaCl and 250 mmmol kg −1 urea (NH2CONH2) using tensiometric and fluorometric techniques at 298.15 K temperature has been studied. A tensiometry study disclosed decreasing in surface tension ( γ ) along with critical micelle concentration ( cmc ) of NaIBU and NaTaC mixture, signifying a noteworthy interaction between studied components. Salt decreases the cmc of amphiphiles whereas urea increases their cmc in comparison to the aqueous solution. The solution mixture of NaIBU and NaTaC shows lower cmc value as compared to ideal cmc ( cmc id ) value indicating the non-ideality in the current studied systems. Other parameters regarding tensiometric technique such as micellar mole fraction of mixed micelles/mixed interface ( X 1 m / X 1 σ ), micellar/surface interaction parameter ( β m / β σ ), activity coefficients ( f 1 m / f 1 σ and f 2 m / f 2 σ ) of the mixed micelles/mixed interface, surface excess concentration ( Γ max ), excess Gibbs energy of mixed monolayer/mixed micelle formation ( Δ G ex σ / Δ G ex m ) etc. were estimated. The non-ideality of mixing expressed in terms of the interaction parameter ( β m / β σ ). Various thermodynamic parameters for current systems in all different media were obtained and discussed in detail. The aggregation number ( N agg ), as well as other related parameters regarding fluorescence study, were also evaluated. The higher values of N agg show the being of hydrophobic interactions along with sustains synergism. [ABSTRACT FROM AUTHOR]

Graphitic-C 3 N 4 (g-C 3 N 4 ) nanosheets were prepared by a simple and environmentally friendly thermal oxidation etching method with ultrasonic. The crystal structure, surface functional groups, surface morphology of g-C 3 N 4 and the adsorption of Eu(III), La(III), Nd(III) and Th(IV) on g-C 3 N 4 were investigated. The maximum adsorption capacities of Eu(III), La(III), Nd(III) and Th(IV) on g-C 3 N 4 were 155.0, 122.3, 132.5 and 185.6 mg/g at 333 K, which showed excellent adsorption capacity. The adsorption reached equilibriums within 7 h, and the adsorption kinetics of Eu(III), La(III), Nd(III) and Th(IV) followed the pseudo-second-order kinetic model well. The adsorption isotherms of La(III), Nd(III) fitted with Langmuir models but Eu(III), Th(IV) fitted with Freundlich models well, respectively. The calculation of thermodynamic data indicated the adsorption was a spontaneous and endothermic process. Experimental results of this work demonstrated that g-C 3 N 4 nanosheets was a promising economical material for the removal of Eu(III), La(III), Nd(III) and Th(IV) from aqueous solutions. [ABSTRACT FROM AUTHOR]