Thermodynamics of Azo Dye Adsorption on a Newly Synthesized Titania-Doped Silica Aerogel by Cogelation: A Comparative Investigation with Silica Aerogels and Activated Charcoal.

The adsorption isotherms of azo dyes on a newly synthesized titania-doped silica (TdS) aerogel compared to silica aerogels and activated charcoal (AC) are systematically investigated. Monolithic TdS aerogels were synthesized by the cogelation process followed by supercritical drying of tetraethyl orthosilicate (TEOS) as a gel precursor and titanium(IV) isopropoxide (TTIP) as a metal complex precursor for co-polymerization in ethanol solvent. An acid-base catalyst was used for the hydrolysis and condensation of TEOS and TTIP. The effect of Ti4+ doping in a silica aerogel on the mesoporous structure and the adsorption capacity of methylene blue (MB) and crystal violet (CV) dyes were evaluated from the UV-vis absorption spectra. In order to compare the adsorption isotherms, the surface areas of silica and TdS aerogels were first normalized with respect to AC, as adsorption is a surface phenomenon. The azo dye equilibrium adsorption data were analyzed using different isotherm equations and found to follow the Langmuir adsorption isotherm. The maximum monolayer adsorption capacities for the adsorbent TdS aerogel normalized with the AC of the Langmuir isotherm are 131.58 and 159.89 mg/g for MB and CV dyes, respectively. From the Langmuir curve fitting, the Q max value of the TdS aerogel was found to increase by 1.22-fold compared to AC, while it increased 1.25-1.53-fold compared to the silica aerogel. After four cycles, regeneration efficiency values for MB and CV dyes are about 84 and 80%, respectively. The study demonstrates the excellent potential and recovery rate of silica and TdS aerogel adsorbents in removing dyes from wastewater. The pore volume and average pore size of the new aerogel, TdS, were found to be lower than those of the silica aerogel. Thus, a new TdS aerogel with a high capacity of adsorption of azo dyes is successfully achieved.

Construction of Waste Chalk Powder into mpg-C3N4-CaSO4 as an Efficient Photocatalyst for Dye Degradation under UV-Vis Light and Sunlight.

In this article, we present the synthesis of calcium sulfate nanoparticles (CaSO4 NPs) from waste chalk powder by the calcination method. These CaSO4 NPs were utilized for the construction of a mesoporous graphitic carbon nitride-calcium sulfate (mpg-C3N4-CaSO4) photocatalyst. Synthesized materials were confirmed by several characterization techniques. The photocatalytic performance of the synthesized samples was tested by the degradation of methylene blue (MB) in the presence of both UV-vis light and sunlight. The efficiency of photocatalytic degradation of MB dye using the optimized mpg-C3N4-CaSO4-2 composite reached 91% within 90 min in the presence of UV-vis light with superb photostability and recyclability after five runs compared to individual mpg-C3N4 and CaSO4 NPs and reached 95% within 120 min under sunlight. Histotoxicological studies on fish liver and ovary indicated that the dye containing the solution damaged the structure of the liver and ovary tissues, whereas the photodegraded solution of MB was found to be less toxic and caused negligible alterations in their typical structure similar to the control group.

Tetraphenylethene-Based Fluorescent Chemosensor with Mechanochromic and Aggregation-Induced Emission (AIE) Properties for the Selective and Sensitive Detection of Hg2+ and Ag+ Ions in Aqueous Media: Application to Environmental Analysis.

It is critical to design a novel and simple bifunctional sensor for the selective and sensitive detection of ions in an aqueous media in environmental samples. As a result, in this study, tetraphenylethene hydrazinecarbothioamide (TPE-PVA), known as probe 1, was successfully synthesized and characterized as having impressive photophysical phenomena such as aggregation-induced emission (AIE) and mechanochromic properties by applying mechanical force to the solid of probe 1. The emission of the solid of probe 1 changed from turquoise blue to lemon yellow after grinding, from lemon yellow to parakeet green after annealing at 160 °C, and to arctic blue after fuming with DCM. Such characteristics could lead to a variety of applications in several fields. The probe was implemented and demonstrated remarkable selectivity and sensitivity toward mercury(II) and silver(I) ions by substantially switching off emission over other cations. Following an extensive photophysical analysis, it was discovered that detection limits (LOD) as low as 0.18344 and 0.2384 µg mL-1 for Hg2+ and Ag+, respectively, are possible with a quantum yield (Φ) of 2.26. Probe 1 was also explored as a Hg2+ and Ag+ paper strip-based sensor and kit for practical use. The binding mechanisms of probe 1 (TPE-PVA) with Hg2+ and Ag+ were confirmed by 1H NMR titration. These results could lead to the development of reliable onsite Hg2+ and Ag+ fluorescent probes in the future.

Structure-engineering of core-shell ZnCo2O4@NiO composites for high-performance asymmetric supercapacitors.

The implementation of a structure-designed strategy to construct hierarchical architectures of multicomponent metal oxide-based electrode materials for energy storage devices is in the limelight. Herein, we report NiO nanoflakes impregnated on ZnCo2O4 nanorod arrays as ZnCo2O4@NiO core-shell structures on a flexible stainless-steel mesh substrate, fabricated by a simple, cost-effective and environmentally friendly reflux condensation method. The core-shell structure of ZnCo2O4@NiO is used as an electrode material in a supercapacitor as it provides a high specific surface area (134.79 m2 g-1) offering high electroactive sites for a redox reaction, reduces the electron and ion diffusion path, and promotes an efficient contact between the electroactive material and electrolyte. The binder-free ZnCo2O4@NiO electrode delivers a high specific capacitance of 882 F g-1 at 4 mA cm-2 current density and exhibits remarkable cycling stability (∼85% initial capacitance retention after 5000 charge-discharge cycles at 10 mA cm-2). The asymmetric supercapacitor device ZnCo2O4@NiO//rGO delivered a maximum energy density of 46.66 W h kg-1 at a power density of 800 W kg-1. The device exhibited 90.20% capacitance retention after 4000 cycles. These results indicate that the ZnCo2O4@NiO architecture electrode is a promising functional material for energy storage devices.

Marigold micro-flower like NiCo2O4 grown on flexible stainless-steel mesh as an electrode for supercapacitors.

Nanostructured NiCo2O4 is a promising material for energy storage systems. Herein, we report the binder-free deposition of porous marigold micro-flower like NiCo2O4 (PNCO) on the flexible stainless-steel mesh (FSSM) as (PNCO@FSSM) electrode by simple chemical bath deposition. The SEM and EDS analysis revealed the marigold micro-flowers like morphology of NiCo2O4 and its elemental composition. The porous nature of the electrode is supported by the BET surface area (100.47 m2 g-1) and BJH pore size diameter (∼1.8 nm) analysis. This PNCO@FSSM electrode demonstrated a specific capacitance of 530 F g-1 at a high current density of 6 mA cm-2 and revealed 90.5% retention of specific capacitance after 3000 cycles. The asymmetric supercapacitor device NiCo2O4//rGO within a voltage window of 1.4 V delivered a maximum energy density of 41.66 W h kg-1 at a power density of 3000 W kg-1. The cyclic stability study of this device revealed 73.33% capacitance retention after 2000 cycles. These results indicate that the porous NiCo2O4 micro-flowers electrode is a promising functional material for the energy storage device.

One-Pot in Situ Hydrothermal Growth of BiVO4/Ag/rGO Hybrid Architectures for Solar Water Splitting and Environmental Remediation.

BiVO4 is ubiquitously known for its potential use as photoanode for PEC-WS due to its well-suited band structure; nevertheless, it suffers from the major drawback of a slow electron hole separation and transportation. We have demonstrated the one-pot synthesis of BiVO4/Ag/rGO hybrid photoanodes on a fluorine-doped tin oxide (FTO)-coated glass substrate using a facile and cost-effective hydrothermal method. The structural, morphological, and optical properties were extensively examined, confirming the formation of hybrid heterostructures. Ternary BiVO4/Ag/rGO hybrid photoanode electrode showed enhanced PEC performance with photocurrent densities (J ph ) of ~2.25 and 5 mA/cm2 for the water and sulfate oxidation, respectively. In addition, the BiVO4/Ag/rGO hybrid photoanode can convert up to 3.5% of the illuminating light into photocurrent, and exhibits a 0.9% solar-to-hydrogen conversion efficiency. Similarly, the photocatalytic methylene blue (MB) degradation afforded the highest degradation rate constant value (k = 1.03 × 10-2 min-1) for the BiVO4/Ag/rGO hybrid sample. It is noteworthy that the PEC/photocatalytic performance of BiVO4/Ag/rGO hybrid architectures is markedly more significant than that of the pristine BiVO4 sample. The enhanced PEC/photocatalytic performance of the synthesized BiVO4/Ag/rGO hybrid sample can be attributed to the combined effects of strong visible light absorption, improved charge separation-transportation and excellent surface properties.

Anchoring Ultrafine ZnFe2O4/C Nanoparticles on 3D ZnFe2O4 Nanoflakes for Boosting Cycle Stability and Energy Density of Flexible Asymmetric Supercapacitor.

Heterostructure-based metal oxide thin films are recognized as the leading material for new generation, high-performance, stable, and flexible supercapacitors. However, morphologies, like nanoflakes, nanotubes, nanorods, and so forth, have been found to suffer from issues related to poor cycle stability and energy density. Thus, to circumvent these problems, herein, we have developed a low-cost, high surface area, and environmentally benign self-assembled ZnFe2O4 nanoflake@ZnFe2O4/C nanoparticle heterostructure electrode via anchoring ZnFe2O4 and carbon nanoparticles using an in situ biomediated green rotational chemical bath deposition approach for the first time. The synthesized ZnFe2O4 nanoflake@ZnFe2O4/C nanoparticle heterostructure thin films demonstrate an excellent specific capacitance of 1884 F g-1 at a current density of 5 mA cm-2. Additionally, all solid-state flexible asymmetric supercapacitor devices were designed on the basis of ZnFe2O4 nanoflake@ZnFe2O4/C nanoparticle heterostructures as the negative electrode and reduced graphene oxide and energy density of 81 Wh kg-1 at a power density of 3.9 kW kg-1. Similarly, the asymmetric device exhibits ultralong cycle stability of 35 000 cycles by losing only 2% capacitance. The excellent performance of the device is attributed to the self-assembled organization of the heterostructures. Moreover, the in situ biomediated green strategy is also applicable for the synthesis of other metal oxide and carbon-based heterostructure electrodes.

Fern-like rGO/BiVO4 Hybrid Nanostructures for High-Energy Symmetric Supercapacitor.

Herein, we demonstrate the synthesis of rGO/BiVO4 hybrid nanostructures by facile hydrothermal method. Morphological studies reveal that rGO sheets are embedded in the special dendritic fern-like structures of BiVO4. The rGO/BiVO4 hybrid architecture shows the way to a rational design of supercapacitor, since these structures enable easy access of electrolyte ions by reducing internal resistance. Considering the unique morphological features of rGO/BiVO4 hybrid nanostructures, their supercapacitive properties were investigated. The rGO/BiVO4 electrode exhibits a specific capacitance of 151 F/g at the current density of 0.15 mA/cm2. Furthermore, we have constructed rGO/BiVO4 symmetric cell which exhibits outstanding volumetric energy density of 1.6 mW h/cm3 (33.7 W h/kg) and ensures rapid energy delivery with power density of 391 mW/cm3 (8.0 kW/kg). The superior properties of symmetric supercapacitor can be attributed to the special dendritic fern-like BiVO4 morphology and intriguing physicochemical properties of rGO.

Contact angle measurements: a preliminary diagnostic tool for evaluating the performance of ZnFe2O4 nano-flake based supercapacitors.

Contact angle measurements (surface wettability) of the electrolytes (1 M KOH, NaOH and LiOH) and their combination (1 M 1 : 1 v/v LiOH + KOH, NaOH + KOH and LiOH + NaOH) in contact with ZnFe2O4 nano-flake based electrodes is used as an empirical diagnostic tool to pre-evaluate the performance of a supercapacitor prior to actual fabrication of the device.

Magnetically separable Ag3PO4/NiFe2O4 composites with enhanced photocatalytic activity.

Magnetically separable Ag3PO4/NiFe2O4 (APO/NFO) composites were prepared by an in situ precipitation method. The photocatalytic activity of photocatalysts consisting of different APO/NFO mass ratios was evaluated by degradation of methylene blue (MB) under visible light irradiation. The excellent photocatalytic activity was observed using APO/NFO5 (5% NFO) composites with good cycling stability which is higher than that of pure Ag3PO4 and NiFe2O4. All the APO/NFO composites showed good magnetic behavior, which makes them magnetically separable after reaction and reusable for several experiments. Photoconductivities of pure and composite samples were examined to study the photoresponse characteristics. The current intensity greatly enhanced by loading NFO to APO. Furthermore, the photocatalytic performance of the samples is correlated with the conductivity of the samples. The enhancement in the photocatalytic activity of APO/NFO composites for MB degradation is attributed to the excellent conductivity of APO/NFO composites through the co-catalytic effect of NFO by providing accelerated charge separation through the n-n interface.

Wurtzite CZTS nanocrystals and phase evolution to kesterite thin film for solar energy harvesting.

A quaternary indium- and gallium-free kesterite (KS)-based compound, copper zinc tin sulfide (Cu2ZnSnS4, CZTS), has received significant attention for its potential applications in low cost and sustainable solar cells. It is well known that the reaction time, reactivity of the precursors, and types of capping ligands used during the synthesis of colloidal nanocrystals (NCs) strongly influence the crystallographic phase of the NCs. In this research, a non-toxic and green synthetic strategy for both the synthesis of CZTS NCs and the fabrication of a highly efficient CZTS absorber layers using an ink formulation without a toxic solvent, which meets the comprehensive framework for green chemistry that covers major aspects of the environmental strain, is demonstrated. In particular, pure metastable wurtzite (WZ) CZTS NCs are synthesized using the environmentally harmless, polyol mediated hot-injection (HI) technique at a low reaction temperature. The influence of the reaction time on the properties of the CZTS NCs is investigated in detail. Based on detailed reaction time dependent phase evolution, a possible growth and formation mechanism is proposed. Furthermore, a scalable, low cost, binder free ink formulation process without ligand exchange is developed using ethanol as the dispersal solvent. The as-prepared WZ-derived CZTS NC thin films are observed to undergo a phase transformation to KS during annealing in a sulfur vapor atmosphere via rapid thermal annealing above 500 °C, and surprisingly, this process results in fully sintered, compact and uniform CZTS thin films with large sized grains. The best solar cell device fabricated using a CZTS absorber that was sulfurized at an optimized temperature exhibits a power conversion efficiency of 2.44%, which is the highest efficiency obtained using the polyol-based HI route.

Carbon- and oxygen-free Cu(InGa)(SSe)2 solar cell with a 4.63% conversion efficiency by electrostatic spray deposition.

We have demonstrated the first example of carbon- and oxygen-free Cu(In,Ga)(SSe)2 (CIGSSe) absorber layers prepared by electrospraying a CuInGa (CIG) precursor followed by annealing, sulfurization, and selenization at elevated temperature. X-ray diffraction and scanning electron microscopy showed that the amorphous as-deposited (CIG) precursor film was converted into polycrystalline CIGSSe with a flat-grained morphology after post-treatment. The optimal post-treatment temperature was 300 °C for annealing and 500 °C for both sulfurization and selenization, with a ramp rate of 5 °C/min. The carbon impurities in the precursor film were removed by air annealing, and oxide that was formed during annealing was removed by sulfurization. The fabricated CIGSSe solar cell showed a conversion efficiency of 4.63% for a 0.44 cm(2) area, with Voc = 0.4 V, Jsc = 21 mA/cm(2), and FF = 0.53.

Synthesis and enhancement of photocatalytic activities of ZnO by silver nanoparticles.

Herein, we reports synthesis, characterization and photocatalytic degradation of Rhodamine B under natural sunlight using zinc oxide and Ag-ZnO composite. Zinc oxide nanoparticles were prepared by simple wet chemical method using ethanol-water mixture. Ag-ZnO composite was prepared in two steps by dispersing synthesized ZnO in silver nitrate solution and subsequently reducing it with Ocimum tenuiflorum leaves extract as bioreducing agent. The synthesized bare zinc oxide and Ag-ZnO composite was characterized by various techniques like XRD, DRS, FE-SEM, TEM, SAED, PSD, Zeta potentials, etc. Zinc oxide being wide band gap material can absorbs UV light from solar spectrum which is only 5% so is not efficient material for dye degradation under sunlight. The absorption of visible light was increased by preparing the Ag-ZnO composite. The enhancement in photocatalytic activities of Ag-ZnO composite was observed than bare ZnO. This enhancement is due to shift of absorption edge of ZnO in visible region and decrease in band gap.

Bioinspired synthesis of highly stabilized silver nanoparticles using Ocimum tenuiflorum leaf extract and their antibacterial activity.

Biosynthesis of nanoparticles is under exploration due to wide biomedical applications and research interest in nanotechnology. We herein reports bioinspired synthesis of silver nanoparticles with the aid of novel, non toxic ecofriendly biological material namely Ocimum tenuiflorum leaf extract. It acts as reducing as well as stabilizing agent. An intense surface plasmon resonance band at ∼450 nm in the UV-visible spectrum clearly reveals the formation of silver nanoparticles. The photoluminescence spectrum was recorded to study excitation and emission. TEM and PSD by dynamic light scattering studies showed that size of silver nanoparticles to be in range 25-40 nm. Face centered cubic structure of silver nanoparticles are confirmed by SAED pattern. The charge on synthesized silver nanoparticles was determined by zeta potential. The colloidal solution of silver nanoparticles were found to exhibit high antibacterial activity against three different strains of bacteria Escherichia coli (Gram negative), Corney bacterium (gram positive), Bacillus substilus (spore forming).

Development of an reliable analytical method for synergistic extractive spectrophotometric determination of cobalt(II) from alloys and nano composite samples by using chromogenic chelating ligand.

A synergistic simple and selective spectrophotometric method was developed for the determination of cobalt(II) with 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol [2',4'-dinitro APTPT] as a chromogenic reagent. The proposed method has been described on the basis of synergistic effective extraction of cobalt(II) in presence of pyridine at pH range 9.5-10.2, showed orange-red coloured ternary complex having molar ratio 1:2:2 (M:L:Py). The equilibrium time is 10 min for extraction of cobalt(III) from organic phase. The absorbance of coloured organic layer in chloroform is measured spectrophotometrically at 490 nm against reagent blank. The Beer's law was obeyed in the concentration range 2.5-15 µg mL(-1) of cobalt(II) and optimum concentration range was 5-12.5 µg mL(-1) of cobalt(II) and it was evaluated from Ringbom's plot. The molar absorptivity and Sandell's sensitivity of cobalt(II)-2',4'-dinitro APTPT-pyridine complex in chloroform are 1.109×10(3) L mol(-1) cm(-1) and 0.053 µg cm(-2), respectively while molar absorptivity and Sandell's sensitivity of cobalt(II)-2',4'-dinitro APTPT complex in chloroform are 6.22×10(2) L mol(-1) cm(-1) and 0.096 µg cm(-2), respectively. The composition of cobalt(II)-2',4'-dinitro APTPT-pyridine complex (1:2:2) was established by slope ratio method, mole ratio method and Job's method of continuous variation. The ternary complex was stable for more than 48 h. The interfering effects of various cations and anions were also studied, and use of suitable masking agents enhances the selectivity of the method. The method is successfully applied for the determination of cobalt(II) in binary, synthetic mixtures and real samples. A repetition of the method was checked by finding relative standard deviation (R.S.D.) for n=5 which was 0.15%. The reliability of the method is confirmed by comparison of experimental results with atomic absorption spectrophotometer.

Dissipation and distribution behavior of azoxystrobin, carbendazim, and difenoconazole in pomegranate fruits.

The dissipation behavior and degradation kinetics of azoxystrobin, carbendazim, and difenoconazole in pomegranate are reported. Twenty fruits/hectare (5 kg) were collected at random, ensuring sample-to-sample relative standard deviation (RSD) within 20-25%. Each fruit was cut into eight equal portions, and two diagonal pieces per fruit were drawn and combined to constitute the laboratory sample, resulting in RSDs <6% (n = 6). Crushed sample (15 g) was extracted with 10 mL of ethyl acetate (+ 10 g Na(2)SO(4)), cleaned by dispersive solid phase extraction on primary secondary amine (25 mg) and C(18) (25 mg), and measured by liquid chromatography tandem mass spectrometry. The limit of quantification was ≤0.0025 µg g(-1) for all the three fungicides, with calibration linearity in the concentration range of 0.001-0.025 µg mL(-1) (r(2) ≥ 0.999). The recoveries of each chemical were 75-110% at 0.0025, 0.005, and 0.010 µg g(-1) with intralaboratory Horwitz ratio <0.32 at 0.0025 µg g(-1). Variable matrix effects were recorded in different fruit parts viz rind, albedo, membrane, and arils, which could be correlated to their biochemical constituents as evidenced from accurate mass measurements on a Q-ToF LC-MS. The residues of carbendazim and difenoconazole were confined within the outer rind of pomegranate; however, azoxystrobin penetrated into the inner fruit parts. The dissipation of azoxystrobin, carbendazim, and difenoconazole followed first + first order kinetics at both standard and double doses, with preharvest intervals being 9, 60, and 26 days at standard dose. At double dose, the preharvest intervals extended to 20.5, 100, and 60 days, respectively.

Synergistic extraction and spectrophotometric determination of copper(II) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol: analysis of alloys, pharmaceuticals and biological samples.

A simple and selective spectrophotometric method was developed for the determination of copper(II) with 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol [2',4'-dinitro APTPT] as a chromogenic reagent. The procedure was based on the synergistic extraction of copper(II) with 2',4'-dinitro APTPT in the presence of 0.5 mol L(-1) pyridine to give green colored ternary complex of a molar ratio 1:2:2 (M:L:Py) in the pH range 8.7-10.5. It exhibits a maximum absorption of colored complex at 445 nm and 645 nm in chloroform against the reagent blank. Beer's law was followed in the concentration range 10-80 µg mL(-1) of copper(II) and optimum range of 20-70 µg mL(-1) the metal as evaluated from Ringbom's plot. The molar absorptivity and Sandell's sensitivity of copper(II)-2',4'-dinitro APTPT-pyridine complex in chloroform are 0.87×10(3) L mol(-1)c m(-1) and 0.072 µg cm(-2), respectively. The interfering effects of various cations and anions were also studied, and use of suitable masking agents enhances the selectivity of the method. The proposed method is rapid, reproducible and successfully applied for the determination of copper(II) in binary and synthetic mixtures, alloys, pharmaceutical formulations, environmental and fertilizer samples. Comparison of the results with those obtained using an atomic absorption spectrophotometer also tested the validity of the method.

Synergistic liquid-liquid extractive spectrophotometric determination of gold(III) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol.

Synergistic liquid-liquid extractive spectrophotometric determination of gold(III) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydro pyrimidine-2-thiol [2',4'-dinitro APTPT] has been described. Equal volumes (5cm(3)) of the 2',4'-dinitro APTPT (0.02molL(-1)) in the presence of pyridine (0.5molL(-1)) form an orange-red coloured ternary complex with gold(III) of molar ratio 1:1:1 at pH 1.8-2.4 with 5min of shaking. The absorbance of coloured organic layer in 1,2-dichloroethane is measured spectrophotometrically at 445nm against reagent blank. A pronounced synergism has been observed by the binary mixture of 2',4'-dinitro APTPT and pyridine, which shows that the enhancement in the absorbance is observed in the presence of pyridine by the adduct formation in the organic phase. Beer's law was obeyed in the concentration range 2.5-20.0microgmL(-1), with molar absorptivity and Sandell's sensitivity values of 8.7x10(3)dm(3)mol(-1)cm(-1) and 0.023microgcm(-2) respectively. A repetition of the method was checked by finding relative standard deviation (R.S.D.) (n=10) which was 0.17%. The composition of the gold(III)-2',4'-dinitro APTPT-pyridine adduct was established by slope analysis, molar ratio and Job's method. The ternary complex was stable for more than 48h. The influence of various factors such as pH, 2',4'-dinitro APTPT concentration, solvent and pyridine on the degree of complexation has been established. A number of foreign ions tested for their interferences and use of suitable masking agents wherever necessary are tabulated, which show that selectivity of the method has been enhanced. The method is successfully employed for the determination of gold(III) in binary, synthetic mixtures and ayurvedic samples. The reliability of the method is assured by inter-comparison of experimental values, using an atomic absorption spectrometer.

Solvent extraction separation of rhodium(III) with N-n-octylaniline as an extractant.

Solvent extraction separation method for the determination of rhodium(III) has been described. Selective and quantitative extraction of rhodium(III) by N-n-octylaniline, a high molecular weight amine (HMWA) into xylene takes place from aqueous sodium malonate medium. The effect of concentration of malonate, N-n-octylaniline, role of various diluents, stripping agents and foreign ions on the extraction of rhodium(III) has been studied. The procedure offers distinct improvements in need of real sample analysis and environmental safety as the extraction procedure carried out in weak organic acid media.