Flotation behavior and adsorption mechanism of(1-hydroxy-2-methyl-2-octenyl) phosphonic acid to cassiterite

The flotation behavior and adsorption mechanism of novel（1-hydroxy-2-methyl-2-octenyl） phosphonic acid（HEPA） to cassiterite were investigated by micro-flotation tests, zeta potential measurements, FTIR determination and density functional theory（DFT） calculation. The flotation results demonstrated that HEPA exhibited superior collecting performance compared with styrene phosphonic acid（SPA）. The cassiterite recovery maintained above 90% over a wide pH range of 2-9 with 50 mg/L HEPA. The results of zeta potential measurement and FTIR detection indicated that the adsorption of HEPA onto cassiterite was mainly attributed to the chemisorption between HEPA monoanions and Sn species on mineral surfaces. The DFT calculation results demonstrated that HEPA monoanions owned higher HOMO energy and exhibited a better affinity to cassiterite than SPA, which provided very clear evidence for the stronger collecting power of HEPA presented in floatation test and zeta potential measurement.

CORROSION BEHAVIOR OF A ZIRCONIUM-TITANIUM BASED PHOSPHONIC ACID CONVERSION COATING ON AA6061 ALUMINIUM ALLOY

The conversion coating was formed by dipping AA6061 in a fluorotitanate/zirconate acid and amino trimethylene phosphonic acid （ATMP） solution at room temperature. The formation process and the anti-corrosion performance of the conversion coating were investigated using electrochemical test and salt spray test （SST）, respectively. The electrochemical test shows that the Zr/Ti and ATMP coating improves the corrosion resistance of AA6061 as good as the chromate （VI） coating. But the results of SST show that the corrosion resistance of Zr/Ti and ATMP coating is not as good as the chromate （VI） coating. The corrosion area is less than 2% after 72 h.

Studies on Adsorption Behavior and Mechanism of Copper(Ⅱ) onto Amino Methylene Phosphonic Acid Resin

The adsorption behavior and the mechanism of a novel chelate resin, amino methylene phosphonic acid resin(APAR) for Cu(Ⅱ) were investigated. Cu(Ⅱ) was quantitatively adsorbed by APAR in the medium of pH=4 09. The statically saturated adsorption capacity is 181 mg/(g resin). Cu(Ⅱ) adsorbed on APAR can be eluted by 1 0-3 0 mol/L HCl. The rate constant is k 298 =5 58×10 -5 s -1 . The adsorption of Cu(Ⅱ) on APAR follows the Freundlich isotherm. The Δ H of the adsorption is 3 91 kJ/mol. The apparent activation energy is E a=21 4 kJ/mol. The coordination molar ratio of APAR to Cu(Ⅱ) is 1/1. It is shown that the nitrogen and the oxygen atoms in the functional group of APAR coordinate to Cu(Ⅱ).

Sorption Behavior and Mechanism of Indium(Ⅲ) onto Amino Methylene Phosphonic Acid Resin

The sorption behavior of amino methylene phosphonic acid resin (APAR) for In (Ⅲ ) was investigated . Experimental results show that In ( Ⅲ ) adsorbed on APAR can be elated with 2mol · L -1 HCl. The apparent rate constant is k29 = 1.50 × 10-5s-1. The sorption behavior of APAR for In ( Ⅲ ) obeys the Freundlich isotherm. The themodynamic parameters of sorption, enthalpy change ()H, free energy change ()G and entropy change ()S of sorption (APAR) for In ( Ⅲ ) are 24.1 kJ·mol-1, -35. 1kJ· mol-1 and 200J· mol-1·K-1 respectively. The coordination molar ratio of the functional group of APAR to In( Ⅲ ) is 2:1. The sorption mechanism of APAR for In( Ⅲ ) was examined by IR spectrometry.

Hydrophobic flocculation flotation of rutile fines in presence of styryl phosphonic acid

The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid（SPA） was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based particle size analysis, adsorption measurements and DLVO theory. The flotation tests indicated that rutile fines could be flocculated by SPA, and pH, shear force（stirring speed） and stirring time played significant roles in flocculation. The isoelectric point（IEP） and zeta-potential in whole range all moved to negative values as SPA was added according to the results from zeta-potential measurement. It was demonstrated that the primary reason for above was chemical adsorption. The laser-based particle size results showed the particle size at a stirring speed of 1800 r/min and 1000 mg/L SPA was the largest in all experiments. Furthermore, using the optical microscope observation and flotation tests, it was important for flotation of rutile fines to produce the flocculant. In the light of above-mentioned facts, floc flotation of rutile fines could be induced in the form of chemical adsorption by SPA to increase particle size. The data calculated from DLVO theory also indicated that chemical adsorption was the main reason for the formation of flocculant.

Adsorption of Macroporous Phosphonic Acid Resin for Nickel

Tje adsorption bchavior and mechanism of a novel chelate resin,macroporous phosphonic acid resin（PAR）for Ni（Ⅱ）were imestigated.The stotically saturated adsorption capacity is 64.3mg·g^-1 resin at 298K in HAc-NaAc medium.The Ni（Ⅱ）adsorbed on PAR can be eluted by 0.5mal·L^-1 HCl and the elution percentage reaches 96.6%.The resin can be regenerated and reused without abvious decrease in adsorption capacity.The apparent adsorption rate constant is k298=2.6×10^-5s^-1.The adsorption behavior of PAR for Ni（Ⅱ）obeys the Freundllich isotherm.The thermodynamie adsorption parameters.enthalpy change △H,free energy change △G and entropy change △S of PAR for Ni（Ⅱ）are 3.36kJ·mol^-1,-5.47kJ·mol^-1 and 29.6J·mol^-1·K^-1,respectively.The apparent activation energy is Ea=12.2kJ·mol^-1,The molar coordination ratio of the functional group of PAR to Ni（Ⅱ）is about 4：1.The adsorption mechanism of PAR for Ni（Ⅱ）was examined by a chemical method and IR spectrometry.

STUDIES ON THE SORPTION OF MACROPOROUS PHOSPHONIC ACID RESIN FOR LANTHANUM

The influences of medium pH sorption temperature, sorption time, etc. on thesorption capacity of macroporous Phosphonic acid resin for La3+ were determined Thesorption rate constant was k298 = 7.64×10-5 s-1. The complex ratio of phosphonicgroups of the resin to La3+ was 3:1. The basic sorption parameters were determinedThe sorption mechanism of macroporous phosphonic acid resin for La3+ was examinedby chemical analysis and IR- spectrometry.

Adsorption Behaviors and Mechanism of Macroporous PhosphonicAcid Resin for Gadolinium

The adsorption behaviors and mechanism of a novel chelate resin, macroporous phosphonic acid resin(PAR)for Gd(Ⅲ)were investigated. The statically and dynamically saturated adsorption capacity is respectively 308 mg·g^(-1)resin and 296 mg·g^(-1)resin at 298 K in HAc-NaAc medium at pH 5.6. Gd(Ⅲ)adsorbed on PAR can be reductively eluted by 0.5～5.0 mol·L^(-1) HCl used as eluant and the elution percentage is up to 94.7% in 1.0 mol·L^(-1) HCl. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k_(298)=3.96×10^(-5) s^(-1). The adsorption behavior of PAR for Gd(Ⅲ) conforms to the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change △H of PAR for Gd(Ⅲ)is 22.6kJ·mol^(-1). The apparent adsorption activation energy(Ea)of PAR for Gd(Ⅲ)is 5.0 kJ·mol^(-1). The molar coordination ratio of the functional group of PAR to Gd(Ⅲ)is about 3∶1. The adsorption mechanism of PAR for Gd(Ⅲ)was examined by using chemical method and IR spectrometry.

Studies on the Adsorption of Amino Methylene Phosphonic Acid Resin for Holmium(Ⅲ)

The adsorption behavior and mechanism of a novel chelate resin, amino methylene phosphonic acid resin (APAR) for Ho(Ⅲ) were investigated. The statically saturated adsorption capacity is 258 mg·g^(-1) resin at 298 K in HAc-NaAc medium. The Ho(Ⅲ) adsorbed on APAR can be repeatedly eluted by 3.0 mol·L^(-1) HCl and the elution percentage is as high as 95.8%. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k_(298)=1.14×10^(-5) s^(-1). The adsorption behavior of APAR for Ho(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change ΔH of APAR for Ho(Ⅲ) is 11.4 kJ·mol^(-1). The apparent activation energy is E_a=15.8 kJ·mol^(-1). The molar coordination ratio of the functional group of APAR to Ho(Ⅲ) is about 2∶1. The adsorption mechanism of APAR for Ho(Ⅲ) was examined by using chemical method and IR spectrometry.

Adsorption behavior and mechanism of amino methylene phosphonic acid resin for Ag(Ⅰ)

The sorption properties of amino methylene phosphonic resin(APAR) for Ag(Ⅰ) were studied. The amino methylene phosphonic acid resin(APAR) has a good adsorption ability for Ag(Ⅰ) at pH=6.0 in the HAc-NaAc medium. The statically saturated adsorption capacity is 272 mg/g resin, Ag(Ⅰ) adsorbed on APAR can be eluted by 5% (NH2)2CS-0.5 mol/L hydrochloric acid quantitatively. The adsorption rate constants determined under various temperatures are k15℃=3.89×10?5 s?1, k25℃=5.93×10?5 s?1, k35℃=7.59×10?5 s?1, k45℃=9.45×10?5 s?1, respectively. The apparent activation energy of adsorption, Ea is 22.8 kJ/mol, the enthalpy change (?H) of sorption is 17.4 kJ/mol. The adsorption mechanism shows that the functional group of APAR coordinates with Ag(Ⅰ) to form coordination bond, the coordination molar ratio of the functional group of APAR to Ag(Ⅰ) is 1∶1.

Synergistic extraction of praseodymium with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and 8-Hydroxyquinoline

The synergistic extraction of Pr^3＋ from hydrochloric medium using mixture of 2-ethylhexyl phosphonic acid mono- 2-ethylhexyl ester （P507, HL） and 8-Hydroxyquinoline （HQ） in heptane was investigated. The effect of equilibrium of aqueous acidity on extraction of Pr^3＋ was discussed. The effect of extractant concentraction, different diluents, equilibrium time and acetate ion concentration oil extraction reaction were also studied. With a method of double-logarithmic slope, composition of the extracted species on 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and 8-Hydroxyquinoline was derived. The result shows that the synergistic extraction system not only overcomes emulsification of 8-Hydroxyquinoline, but also shows perfect capacity of synergistic extraction. The largest synergistic enhancement factor can be calculated to be 5.49 at pH 3.6 for Pr^3＋.

Adsorption Behavior and Mechanism of Macroporous Phosphonic Acid Resin for Lu^(3+)

The article is based on a research on the adsorption behavior and adsorption mechanism of macroporous phosphonic acid resin (PAR) for Lu 3+ and the influence of the medium’s pH, adsorption temperature, adsorption time, etc on adsorbing Lu 3+ . The best value of medium’s pH to the adsorption of PAR for Lu 3+ was found to be 4.92. The static adsorption maximum capacity of PAR for Lu 3+ is 220?mg·g -1 . The thermodynamic adsorption parameters are respectively ΔH=11.3?kJ·mol -1 , ΔS=46.3?J·mol -1 ·K -1 , ΔG=-2.50?kJ·mol -1 and the apparent activity energy is E_a=31.4?kJ·mol -1 . The adsorption behavior of PAR for Lu 3+ obeys the Freundlich isotherm. The apparent adsorption rate constant is k_ 298 =4.68 ×10 -5 ?s -1 . The coordinate ratio of the functional radical to Lu 3+ is approximately 4∶1. The best eluant is 1.0?mol·L -1 HCl. The adsorption mechanism of PAR for Lu 3+ was separately confirmed by chemical analysis and IR spectra.

ADSORPTION OF MACROPOROUS PHOSPHONIC ACID RESIN FOR INDIUM

The adsorption kinetics and mechanism of a novel chelate resin, macroporous phosphonic acid resin (PAR) for In(III) were investigated. The statically saturated adsorption capacity is 216mg穏-1resin at 298K in HAc-NaAc medium. The apparent adsorption rate constant is k298=4.84?0-5 s-1. The adsorption behavior of PAR for In(III) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change △H, free energy change △G and entropy change △S of PAR for In(III) are 11.5kJ/mol, -12.6kJ/mol and 80.8J/mol稫, respectively. The apparent activation energy is Ea=3.5kJ/mol. The molar coordination ratio of the functional group of PAR to In(III) is about 3∶1.

SORPTION BEHAVIOR AND MECHANISM OF SAMARIUM(III) ON AMINO METHYLENE PHOSPHONIC ACID RESIN

Sm(III) was quantitatively adsorbed by amino methylene phosphonic acid resin (APAR) in the medium of pH=5.0. The statically saturated sorption capacity is 251mg/g·resin. Sm(III) adsorbed on APAR can be reductively eluted by 2.0mol/L HCl. The sorption rate constant is k298= 1.35×10-5s-1. The sorption behavior of APAR for Sm(III) obeys the Freundlich isotherm. The enthalpy change △H of sorption is 24.9kJ/mol. The apparent activation energy is Ea=11.7kJ/mol. The sorption mechanism shows that the nitrogen and oxygen atoms of the functional group of APAR coordinated with Sm(III) to form coordination bond.

Extraction Separation of Scandium，Iron and Lutetium with Isopropyl Phosphonic Acid Mono（1－hexyl－4－ethyl）OctylEster

The extraction and stripping of scandium from its sulfate solutions by isopropyl phosphonic acid mono (1-hexyl-4-ethyl) octyl ester (PT-2, HL) diluted with n-hexane are reported. A high efficiency of separation between scandium, iron and lutetium can be achieved by controlling aqueous acidity. Different mechanisms of Sc3+ with PT-2 in various acid range have been proposed.At lower aqueous acidity, it is a cation exchange reaction, while at higher acidity. a solvation reaction was ascertained. Its IR and NMR spectra have been discussed. The effect of temperature on extraction of Sc3+ was observed and thermodynamic functions were calculated.

Adsorption of copper using macroporous phosphonic acid resin

The adsorption behavior and mechanism of a novel chelate resin, macroporous phosphonic acid resin（PAR） for Cu（Ⅱ） were investigated. The statically saturated Cu（Ⅱ） adsorption capacity is 168 mg/g resin at 298K in HAc-NaAc medium. The Cu（Ⅱ） adsorbed on PAR can be eluted by 1.03.0 mol/L HCl and the elution percentage reaches 100%. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is (k=1.64×10-4 s-1) at 298K. The adsorption behavior of PAR for （Cu（Ⅱ）） obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change ΔH, free energy change ΔG and entropy change ΔS of PAR for Cu（Ⅱ） are 11.8 kJ/mol, -2.0 kJ/mol and (46.4 J·mol-1·K-1) respectively. The apparent activation energy is Ea=8.0 kJ/mol. The molar coordination ratio of the functional group of PAR to Cu（Ⅱ） is about 2∶1. The adsorption mechanism of PAR for Cu（Ⅱ） was examined by chemical method and IR spectrometry.

Novel Phosphonoacetic Acid Derivatives.Synthesis of N-(Ethoxycarbonylmethylphosphonyl)-α-Amino Esters and-α-Amino Phosphonic Acid Esters and Their Bioactivities

A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)

SYNTHESES OF HINDERED ALKYL PHOSPHONATES AND PHOSPHONIC & PHOSPHINIC ACIDS

A series of di-n-hexyl alkyl phosphonates with bulky substituent on phosphorus was synthesized by PTC P-alkylation using crown ether.Upon saponification of the resulting di-n-hexyl alkylphosphonates in the presence of crown ether or quaternary ammonium halide, corresponding mono-hexyl esters of alkyl phosphonic acids were prepared.Ultrasonic wave, as we found, can catalyze the reaction between dialkyl phosphite & metallic sodium and hydrolysis of dihexyl alkyl phosphonates.A series of di-t-alkyl phosphinic acids were synthesized by the reaction of Grignard reagent with PCl_3 followed by oxidation with 30% H_2O_2.It was found that the reaction between dibutyl phosphite and Grignard reagent of t-alkyl chloride is a new synthetic method for the preparation of mono-esters of highly hindered alkyl phosphonic acids.

Synthesis of Bifunctional Poly(Vinyl Phosphonic Acid-<i>co</i>-glycidyl Metacrylate-<i>co</i>-divinyl Benzene) Cation-Exchange Resin and Its Indium Adsorption

Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.

Design, synthesis and in vitro evaluation of L-amino acid esters prodrugs of acyclic nucleoside phosphonates as anti-HBV agent

A series of novel L-amino acid esters prodrugs of acyclic nucleoside phosphonates was synthesized and their anti-HBV activity was evaluated in HepG2 2.2.15 cells. Compound 1d exhibited more potent anti-HBV activity and lower cytotoxicity than those of adefovir dipivoxil with EC50 and CC50 values of 0.207 μmol/L and 2530 μmol/L, respectively.