Selective transport of Ag(Ⅰ) ion across a bulk liquid and polymer membranes incorporated with di-N-benzylated O_3N_2 donor macrocycles

<正>The selective bulk liquid membrane and polymer membrane transports of Ag(Ⅰ) from an aqueous solution containing seven metal cations,Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ),Ag(Ⅰ),Cd(Ⅱ) and Pb(Ⅱ),was studied.The source phases contained equimolar concentrations of the above-mentioned cations,with the source and receiving phases being buffered at pH 5.0 and 3.0,respectively. Ag(Ⅰ) ion transport occurred with a good efficiency from the aqueous source phases across the bulk liquid membrane and polymer membrane(derived from cellulose triacetate) containing ligand 1 as the ionophores,into the aqueous receiving phases.Clear transport selectivity for Ag(Ⅰ) was observed using ligand 1.There was no selectivity for the cations using ligand 2 in the both bulk liquid membrane and polymer membrane transports.     

SELECTIVE TRANSPORT OF GOLD（Ⅱ） THROUGH THE LIQUID MEMBRANE CONTAINING POLYTHIOETHER OLIGOMER AS CARRIER

This paper deals with the transport properties of oligomer of polythioether PSA used as moble carrier in bulk liquid membrane for gold(Ⅲ).It was found that Au(Ⅲ) can be transported by PSA from source phase to receiving phase completely under appropriate conditions and only Au(Ⅲ) can be transferred through the liquid membrane to receiving phase from a mixture of Na(I)-Cu(Ⅱ）-Au(Ⅲ）-Fe(Ⅲ）-Pt(Ⅳ） in the following system:HAuCl4-HCl(aq.)/PSA-ClCH2-CH2Cl/(NH2)2CS-HCl(aq.).The transport rate of Au(Ⅲ） depended on the concentration of carrier,the thickness of liquid membrane,the concentration of Au(Ⅲ） in source phase and the acidity of the media.     

Extraction of cobalt(Ⅱ) from aqueous solution by N,N'-carbonyl difatty amides

The development of economic and environmentally friendly extractants to recover cobalt metal is required due to the increasing demand for this metal.In this study,solvent extraction of Co(Ⅱ) from aqueous solution using a mixture of N,N’-carbonyl difatty amides(CDFAs) synthesised from palm oil as the extractant was carried out.The effects of various parameters such as acid,contact time,extractant concentration,metal ion concentration and stripping agent and the separation of Co(Ⅱ) from other metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ) were investigated.It was found that the extraction of Co(Ⅱ) into the organic phase involved the formation of 1:1 complexes.Co(Ⅱ) was successfully separated from commonly associated metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ).Co(Ⅱ) stripping from the loaded organic phase was studied in aqueous solution.These results are useful to recover Co(Ⅱ) from aqueous solution utilising(CDFAs) as an extractant.     

SELECTIVE TRANSPORT OF GOLD(Ⅲ) THROUGH THE LIQUID MEMBRANE CONTAINING POLYTHIOETHER OLIGOMER AS CARRIER

This paper deals with the transport properties of oligomer of polythioether PSA used as mobile carrier in bulk liquid membrane for gold(Ⅲ). It was found that Au(Ⅲ) can be transported by PSA from source phase to receiving phase completely under appropriate conditions and only Au (Ⅲ) can be transferred through the liquid membrane to receiving phase from a mixture of Na(Ⅰ)-Cu(Ⅱ)-Au (Ⅲ) - Fe (Ⅲ) - Pt(Ⅳ) in the following system, HAuCl4 - HCl (aq.)/PSA -ClCH2-CH2Cl/(NH2)2CS-HCl(aq.). The transport rate of Au(Ⅲ) depended on the concentration of carrier, the thickness of liquid membrane, the concentration of Au(Ⅲ) in source phase and the acidity of the media.     

Synthesis of new superabsorbent poly(NIPAAm/AA/N-allylisatin)nanohydrogel for effective removal of As(Ⅴ) and Cd(Ⅱ) toxic metal ions

The present studies highlight the effective removal of As（V） and Cd（II） from aqueous solutions by superabsorbent poly （NIPAAm/AA/N-allylisatin） nanohydrogel. Batch removal studies were performed as a function of treatment time, initial metal ion concentration, pH, and adsorbent dose. TEM micrographs confirm the particle size distribution in the range between 5 nm and 10 rim. The simple and metal ions adsorbed nanohydrogels were characterized by FF-IR, TGA, and EDX analysis. Finally, the equilibrium removal efficiency of the nanohydrogel was analyzed according to the Langmuir and Freundlich adsorption isotherm models which showed the removal of As（V） and Cd（II） metal ions fitted to Freundlich and Langmuir isotherms, respectively. Removal efficiency order of the metal ions is As（V） 〉 Cd（II）.     

磷酸钛离子交换薄层色谱分离无机离子(英文)

The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous,organic and mixed mobile phases.The separation of one ion from several other ions and also ternary and binary separations have been developed.Some important analytical separations are reported.The effect of pH of the mobile phase on retention factor(Rf)values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied.This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationary phase in thin layer chromatography.     

N530-OT-煤油-HCl反萃分散组合液膜体系迁移和分离铜的研究

The transport and separation of copper(Ⅱ) from waste water by a N₅₃₀-OT-kerosene-HCl strip dispersion hybrid liquid membrane system was studied. The influence of penetrant OT, N₅₃₀ concentration, pH in feed phase, membrane area, HCl concentration in stripping phase, and volume ratio of membrane phase to stripping phase on transport and separation were also investigated. The experiments demonstrate that Cu(Ⅱ) can be transported selectively from the binary Cu(Ⅱ) and Fe(Ⅲ) solution to stripping phase and that the transport percentage of Cu(Ⅱ) exceeds 93.8% and Fe(Ⅲ) is only 1.8% after transport of 6 hours.     

Removal of Cd(Ⅱ) from Aqueous Solutions by Natural Freshwater Surface Coatings

Natural freshwater surface coatings(biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous solutions. The batch experiments were carried out to determine the adsorption properties of Cd(Ⅱ) onto the natural surface coatings. The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Cd(Ⅱ) adsorbed on the surface coatings. The results show that the maximum adsorption capacity of the surface coatings is 434.78 μmol Cd/m2(being equal to 0.17 mmol Cd/g of surface coatings or 10.38 mmol Cd/g Fe) and the Cd(Ⅱ) removal from solution media by the natural surface coatings was shown to be strongly affected by solution pH and ion strength. The resulted information also indicates that the maximum Cd removal efficiency(CRE) was determined to be approximately 90% at initial Cd mass concentration of 0.1 mg/L(the concentration limit of Cd (Ⅱ) in wastewaters for discharge in aquatic media in Chinese legislation), and the kinetic adsorption of Cd(Ⅱ) onto the surface coatings is fast with around 70% of the total adsorption-taking place in 150 min in solution under the controlled laboratory conditions (mineral salts solution with defined speciation, ionic strength 0.05 mol/L, and 25 ℃). With the advantage of high Cd adsorption capacity, the natural surface coatings appear to be a potentially effective biosorbent for the removal and recovery of Cd (Ⅱ) from polluted water.     

Selective Pre-concentration and Solid Phase Extraction of Mercury（Ⅱ） from Natural Water by Silica Gel-loaded （E）-N-（1-Thien-2＇-ylethylidene）-1,2-phenylenediamine Phase

Silica gel-loaded （E）-N-（1-thien-2＇-ylethylidene）-1,2-phenylenediamine （TEPDA） phase was synthesized based on physical adsorption approaches. The stability of a chemically modified TEPDA especially in concentrated hydrochloric acid that was then used as a recycling and preconcentration reagent allowed the further uses of silica gel-loaded immobilized TEPDA phase. The application of this silica gel-loaded phase to sorption of a series of metal ions was performed by using different controlling factors such as the pH of the metal ion solution and the equilibration shaking time by the static technique. This difference was interpreted on the basis of selectivity incorporated in these sulfur containing silica gel-loaded TEPDA phases. Hg（Ⅱ） was found to exhibit the highest affinity towards extraction by these silica gel-loaded TEPDA phases. The pronounced selectivity was also confirmed by the determined distribution coefficients （Kd） of all the metal ions, showing the highest value reported for mercury（Ⅱ） extraction by the silica gel immobilized TEPDA phase. The potential applications of the silica gel immobilized TEPDA phase to selective extraction of mercury（Ⅱ） from aqueous solution were successfully accomplished and preconcentration of low concentration of Hg（Ⅱ） （30 pg·mL^-1） from natural tap water with a preconcentration factor of 200 for Hg（Ⅱ） off-line analysis was conducted by cold vapor atomic absorption analysis.     

Preparation and application of a novel orotic acid chelating resin for removal of Cu(Ⅱ) in aqueous solutions

A novel chelating resin OABA,capable of removing Cu(Ⅱ) from aqueous solution,was synthesized via the reaction of macroporous chloromethylated PS-DVB copolymer beads with orotic acid.The elemental analysis(EA),Fourier transform infrared spectroscopy(FT-IR),and scanning electron microscopy microscope-energy dispersive X-ray spectroscopy(SEM-EDS) were used in the characterization of the synthesized chelating resin.Multiple,static batch adsorption experiments were conducted at different initial concentrations and temperatures.OABA showed good adsorption capacity for Cu(Ⅱ) and the equilibrium data could be well matched with the Freundlich isotherm model.Coexisting sodium chloride and calcium chloride in solutions favored the Cu(Ⅱ) adsorption.Moreover,the desorption process of Cu(Ⅱ) was tested and over 90%regeneration efficiency for the spent OABA was achieved at ammonia concentrations ranging from 1.0%to 2.0%.The results suggested that OABA would be a potential alternative adsorbent for Cu(Ⅱ),even with other heavy metal ion treatments of wastewater.     

TRANSFER MECHANISM OF QUININE DRUG ACROSS THE OIL/WATER (O/W) INTERFACE

The transfer phenomena of quinine drug at the aqueous 1,2- dichloroethane (DCE)interface have been studied by the current- scanning polarography. The relationships be-tween the wave height and pH of aqueous phase, concentration of quinine as well as therate of water drop are discussed. The effect of supporting electrolyte, buffer solution andthe nature of organic solvent on the polarographic wave is studied. The transfer char-acteristics of quinine in aqueous phase and in organic phase are compared, The mono- pro-tonated and diprotonated quinines can both transfer at the interface so as to produce twopolarographic waves. The transfer process of quinine at the interface is simultaneouslycontrolled by diffusion and reestablishment of the disturbed protonated equilibrium ofquinine. A further investigation is made by chronopotentiometry. On the basis of thetheoretical analysis, the formulae of the limiting current are derived and discussed. Thetheoretical results are in agreement with the experimental ones.     

Removal of Cd（ Ⅱ ） from Aqueous Solutions by Natural Freshwater Surface Coatings

Natural freshwater surface coatings (biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous solutions. The batch experiments were carried out to determine the adsorption properties of Cd(Ⅱ) onto the natural surface coatings. The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Cd(Ⅱ) adsorbed on the surface coatings. The results show that the maximum adsorption capacity of the surface coatings is 434. 78μmol Cd/m^2 (being equal to 0. 17mmol Cd/g of surface coatings or 10. 38mmol Cd/g Fe) and the Cd(Ⅱ) remnoval from solution media by the natural surface coatings was shown to be strongly affected by solution pH and ion strength. The resulted information also indicates that the maximum Cd removal efficiency(CRE) was determined to be approximately 90% at initial Cd mass concentration of 0. 1mg/L (the concentration limit of Cd (Ⅱ) in wastewaters for discharge in aquatic media in Chinese legislation), and the kinetic adsorption of Cd (Ⅱ) onto the surface coatings is fast with around 70% of the total adsorption-taking place in 150min in solution under the controlied laboratory conditions (mineral salts solution with defined speciation, ionic strength 0. 05mol/L, and 25℃). With the advantage of high Cd adsorption capacity, the natural surface coatings appear to be a potentially effective biosorbent for the removal and recovery of Cd(Ⅱ) from polluted water.     

铜锌超氧化物歧化酶与丝氨酸钴(Ⅱ)的相互作用

The effect of changing the amount of externally added cobalt(Ⅱ) serine, an organic metal compound, and the pH value of the enzyme solution on the interaction of copper zinc superoxide dismutase (Cu 2Zn 2SOD) with cobalt(Ⅱ) serine was studied by means of visible spectroscopy, inductively coupled plasma atomic emission spectrometry and measurement of enzyme activity. It was found that in aqueous solution, there exists a direct interaction of the metal ions of the active center in Cu 2Zn 2SOD with cobalt(Ⅱ) serine. As a result, part of the metal ions in the metalloenzyme were replaced by Co ion to form Co(Ⅱ) substituted derivatives of SOD and the catalytic activity of the enzyme decreased.     

Gold Nanoparticle-based Colorimetric Assay for Determination of Lead(Ⅱ) in Aqueous Media

The authors presented a simple colorimetric assay for the detection of toxic heavy metal lead(Ⅱ) ion(Pb2+).Pentapeptide,cysteine-alanine-leacine-asparagine-asparagine(CALNN),functionalized gold nanoparticles(GNPs) were aggregated in the presence of the divalent metal ion in solution by an ion-templated chelation process,which caused an easily measurable change in the absorption spectrum of the particles.Typically,mono-dispersing GNPs exhibit an absorption band at 522 nm,corresponding to a red color solution,while aggregated GNPs have it at longer wavelengths,corresponding to a purple or blue color solution.The chelation/aggregation process is reversible via the addition of a strong metal ion chelator such as EDTA.Highly selective and sensitive detection of Pb2+ in aqueous solution is thus provided.A detection limit of 0.1 μmol/L of Pb2+ was demonstrated.     

A NOVEL EOR POLYMER (Ⅱ)——INVESTIGATION ON IN-SITU GELATION OF SMRF SYSTEM IN BEREA CORE

In-situ gelation of aqueous sulfomethylated resorcinol formaldehyde (SMRF) system inBerea core has been investigated. Two sets of displacement experiments were conducted with thissystem (containing 5% NaCl, 0. 036% CaCl_2. 2H_2O). The brine permeabilities of the coreswere reduced significantly from about 600 to 0.1 md. The in-situ gelation in Berea core occurreda little bit earlier than gelation anticipated from bulk test in the experiments. The gel time waseasier to control at initial pH between 6 and 8. During injection of SMRF system, the apparentviscosity was less than 1 mPa·s at 41℃.     

Highly Efficient Co-removal of Heavy Metals in Wastewater from Chemical Oxygen Demand Testing Instrument by Cysteine-functionalized Magnetic Nanoparticles

Wastewater discharged from chemical oxygen demand（COD） testing instrument was generally difficult to treat due to its high content of heavy metals and very low pH. In this study, a kind of cysteine-functionalized magnetic nanoparticles（MNPs-Cys） was synthesized and used to treat the wastewater. The synthesized MNPs-Cys as the adsorbent for heavy metal removal from aqueous solutions were systematically investigated. The adsorption dynamic process fit the Langmuir isotherms well with a maximum adsorption capacity of 76.92 mg/g for Cu（Ⅱ）. The adsorbent could be easily regenerated by 0.1 mol/L HNO3, which exhibited a high adsorption performance within 10 cycles. This adsorbent, combined with a developed pretreatment approach, could make Cr（Ⅲ）, Hg（Ⅱ） and Ag（Ⅰ） in the wastewater discharged from COD testing instrument effectively removed and the removal efficiency is more than 99%. This work gave a new insight into the design and synthesis of high-performance materials for treating wastewater with heavy metals.     

ADSORPTION OF METHYLENE BLUE FROM AQUEOUS SOLUTION ON ATTAPULGITE

Batch adsorption experiments were carried out for the removal of methylene blue （MB） from aqueous solution using attapulgite as adsorbent. The effects of various parameters such as temperature, contact time, the pH value, and attapulgite dosage on the adsorption performance were investigated. The standard curve and regression equation were established by spectrophotometry. The adsorption experimental results showed that the adsorption equilibrium data were well in accord with Langmuir adsorptive model. The optimal result was acquired under the experimental condition of attapulgite dosage 0.18g, MB concentration 50.0mg/L, pH 10, and adsorption time 20min at room temperature.     

Organic-inorganic hybrid fluorescent sensor thin films of rhodamine B embedded Ag-SBA 15 for selective recognition of Hg (Ⅱ) ions in water

Nowadays, the rapid and effective detection of low doses of heavy metal pollutants in contaminated water is a timely challenge in environmental pollution research. In this study, a rapid and highly sensitive assay for the detection of Hg~(2+)based on quenching of metal-enhanced fluorescence of rhodamine B(RB)has been fabricated. RB and silver nanoparticle were incorporated into the mesoporous siliceous framework spin cast on a quartz glass through post-synthetic incorporation method. The morphology and crystallinity of mesoporous structure and Ag nanoparticle were characterized by transmission electron microscopy and X-ray diffraction analyses. Photoluminescence assays on the hybrid thin film of RB-Ag-SBA15 showed a high enhancement when compared to the intensity of silver free SBA15-RB in the wavelength of 575 nm. The fluorescence of RB-Ag-SBA15 thin film decreased gradually with the increase in the concentration of Hg~(2+)and the detection limits were 10.54 nmol/L. Furthermore, the fluorescence intensity increased linearly with the concentration of Hg~(2+)in the range from 1.0 ? 10à8mol/L to10 ? 10à8mol/L, with a response time of a few seconds. In addition, this system offers a high selectivity over interfering cations such as Cd~(2+) and Pb~(2+). Overall, we have developed an optical assay having a wellordered mesoporous SBA15 containing Ag-RBfor selective detection of Hg~(2+)in aqueous solution. The scheme combines the advantages of specific binding interactions between Hg~(2+)and RB molecule and optical emission properties of RB. The method is suitable for a single-shot and irreversible analytical assay in a quartz glass/microtiter plate.     

CRITICAL CONCENTRATIONS OF α(1→3)-D-GLUCAN FROM LENTINUS EDODES IN NaOH AQUEOUS SOLUTION

Critical concentrations of α-(1→3)-D-glucan L-FV-Ⅱ from Lentinus edodes were studied by viscometry andfluorescence probe techniques. The dependence of the reduced viscosity on concentration of the glucan in 0.5 mol/L NaOHaqueous solutions with or without urea showed two turning points corresponding to the dynamic contact concentration c_s andthe overlap concentration c~* of the polymer. The values of c_s and c~* were found to be 1×10~(-3) g cm~(-3) and 1.1×10~(-2) g cm~(-3),respectively, for L-FV-Ⅱ in 0.5 mol/L NaOH aqueous solutions. The two critical concentrations of L-FV-Ⅱ in 0.5 mol/LNaOH aqueous solutions were also found to be 1.2×10~(-3) g cm~(-3) fbr c_s and 9.2×10~(-3) g cm~(-3) for c~* from the concentrationdependence of phenanthrene fluorescence intensities. The overlap concentration c~* of L-FV-Ⅱ in 0.5 mol/L NaOH aqueoussolutions was lower than that of polystyrene with same molecular weight in benzene, owing to the fact that polysaccharidetends to undergo aggregation caused by intermolecular hydrogen bonding. A normal viscosity behavior of L-FV-Ⅱ in 0.5 mol/L urea/0.5 mol/L NaOH aqueous solutions can still be observed in an extremely low concentration range at 25℃.     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.