ADSORPTION OF SAMARIUM（III） ON DIGLYCOLAMIDIC ACID RESIN

The sorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR), for Sm(lll) were investigated. The optimal sorption condition of DAAR for Sm(lll) is pH=6.0 in HAc-NaAc medium. The statically saturated sorption capacity is 190mg/g resin at 298K. The Sm(lll) adsorbed on DAAR can be eluted reaching 100% by 0.5-2.0mol/L HCI used as eluant. The resin can be regenerated and reused without apparent decrease of sorption capacity. The apparent sorption rate constant is k298= 1.96×10^-5s^-1. The apparent activation energy is 26kJ/mol. The sorption behavior of DAAR for Sm(lll) obeys the Freundlich isotherm. The thermodynamic sorption parameters, enthalpy change ΔH of DAAR for Sm(lll) is 16.9Kl/mol. The molar coordination ratio of the functional group of DAAR to Sin (111) is 3. The sorption mechanism of DAAR for Sm(lll) was examined by using chemical method and IR spectrometry. The coordination bond was formed between oxygen atoms in the functional group of DAAR and Sin(Ill).     

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 ΔH° 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.     

ADSORPTION OF SAMARIUM(Ⅲ) ON DIGLYCOLAMIDIC ACID RESIN

The sorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin(DAAR), for Sm(Ⅲ) were investigated. The optimal sorption condition of DAAR for Sm(Ⅲ) is pH=6.0 in HAc-NaAc medium. The statically saturated sorption capacity is 190mg/g resin at 298K.The Sm(Ⅲ) adsorbed on DAAR can be ehuted reaching 100% by 0.5～2.0mol/L HCl used as eluant.The resin can be regenerated and reused without apparent decrease of sorption capacity. The apparent sorption rate constant is k29s= 1.96 × 10-5 s-1. The apparent activation energy is 26k J/mol.The sorption behavior of DAAR for Sm(Ⅲ) obeys the Freundlich isotherm. The thermodynamic sorption parameters, enthalpy change △H of DAAR for Sm(Ⅲ) is 16. 9kJ/mol. The molar coordination ratio of the functional group of DAAR to Sm (Ⅲ) is 3. The sorption mechanism of DAAR for Sm(Ⅲ)was examined by using chemical method and IR spectrometry. The coordination bond was formed between oxygen atoms in the functional group of DAAR and Sm(Ⅲ).     

大孔膦酸树脂吸附镱的研究

In this paper the sorption behavior of Yb(Ⅲ) onto the macroporous phosphonic acid resin (MPAR) is reported.Experimental results show that the statically saturated sorption capacity is 328 mg/g*resin;Yb(Ⅲ) adsorbed on MPAR can be eluted by 1mol*L-1 HCl,elution percentage is 91.5%.The apparent rate constant is k298=4.63×10-5s-1.The sorption behavior of MPAR for Yb(Ⅲ) abides the Freundlich isotherm.The themodynamic parameter of sorption:enthalpy change ΔH for Yb(Ⅲ) is 50.4kJ*mol-1.The coordination molar ratio of the functional group of MPAR to Yb(Ⅲ) is 3∶1.The bondforming conditions of MPAR for Yb(Ⅲ) is examined by IR spectrometry.     

ADSORPTION OF MACROPOROUS PHOSPHONIC ACID RESIN FOR INDIUM

The adsorption kinetics and mechanism of a nrovel chelate resin, macroporous phosphonic acid resin (PAR) for In(Ill) were investigated Tile statically saturated adsorption capacity is 216mg·g^-1resin at 298K in HAc-NaAc medium. Tire apparent adsorption rate constant is k298=4.84×10^-5 s^-1. Tile adsorption behavior of PAR for In(Ill) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change △H, free energy change △G and entropychange △S of PAR for In(Ⅲ) are 11.5kmol, -12.6kJmol and 80.8Jmol.K, respectively. The apparent activation energy is Ea=3.5k.l/mol. Tire molar coordination ratio of the functional group of PAR to In(Ⅲ) is about 3:1.     

Kinetics and Mechanism of Exothermic First-stage Decomposition Reaction of 2,6-Bis （2,2,2-trinitroethyl）glycoluril

The thermal behavior, mechanism and kinetic parameters of the exothermic first-stage decomposition of the title compound in a temperature-programmed mode were investigated by means of DSC, TG-DTG and IR. The reaction mechanism was proposed. The kinetic model function in differential form, apparent activation energy(Ea) and pre-exponential factor(A) of this reaction are (3/2)(1-a)[-ln(1-a)]1/3, 185.52 kJ/mol and 1017.78 s-1, respectively. The critical temperature of the thermal explosion of the compound is 201.30 ℃. The values of ΔS≠, ΔH≠ and ΔG≠ of this reaction are 72.46 J/(mol · K), 175.1 kJ/mol and 141.50 kJ/mol, respectively.     

Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Nitroamine Dimers

Ab initio self-consistent field(SCF) and Mφller-Plesset correlation correction methods employing 6-31G^** basis set have been applied to the optimizations of nitroamine dimers.The binding energies have been corrected for the basis set superposition error (BSSE) and the zero-point energy.Theree optimized dimers have been obtained.The BSSE corrected binding energy of the most stable dimer is predicted to be -31.85kJ/mol at the MP4/6-31G^**//MP2/6-31G^** level.The energy barriers of the Walden conversion for -NH2 group are 19.7kJ/mol and 18.3kJ/mol for monomer and the most stable dimer,respectively.The molecular interaction makes the internal rotation around N1-N2 even more difficult.The thermodynamic properties of nitroamine and its dimers at different temperatures have been calculated on the basis of vibrational analyses.The change of the Gibbs free energy for the aggregation from monomer to the most stable dimer at standard pressure and 298.2 K is predicted to be 14.05kJ/mol.     

STUDY ON THE THERMODYNAMIC PROPERTIES OF ADSORPTION OF ETHYL BENZOATE AND DIETHYL PHTHALATE BY PHENOLIC RESIN ADSORBENTS

This paper presents experimental observations on the adsorption of individual solutes by a simple thermodynamic framework, and the equilibrium adsorption of ethyl benzoate and diethyl phthalate on phenolic resin adsorbent in hexane solutions within the temperature range of 293-313 K. The experimental results show that the Freundlich adsorption law is applicable to the adsorption of ethyl benzoate and diethyl phthalate on the adsorbent, since all the correlative factors R‘are larger than 0.99. The negative values of all the isosteric adsorption enthalpies for ethyl benzoate and diethyl phthalate indicate that they undergo exothermic processes, while their magnitudes (19-28 kJ/mol) manifest a hydrogen bonding sorption process. Other thermodynamic properties: the free energy changes and the entropy change associated with the adsorption have been calculated from the Gibbs adsorption equation and the Gibbs-Helmholtz equation.     

THE COORDINATION ADSORPTION OF AMINES ON CARBOXYL RESIN IN Cu~(2+) FORM FROM NON-AQUEOUS MEDIUM AND DESORPTION WITH ANHYDROUS ELUANT

The adsorption of aniline, N-methylaniline and N,N-dimethylaniline onto carboxyl resin in Cu~(2+) form from water,ethanol and n-hexane have been studied. The results show that the adsorption affinities from n-hexane are higher than thatfrom water, and nearly zero from ethanol. The separation factors for the adsorption of these three amines from mixed solutionwere also examined. The results of continuous column operations show that the breakthrough capacity of aniline from n-hexane reaches 90 mg/g dry resin in Cu~(2+) form, and the amines adsorbed can be stripped with anhydrous ethanol effectively.Adsorption onto carboxyl resin in Cu~(2+) form from non-aqueous medium and desorption with anhydrous eluant can overcomethe run-off of Cu~(2+) from the resin, and would show potential advantages in the separation of some water-insoluble naturalproducts.     

STUDY ON THE SORPTION BEHAVIOR OF N—METHYL—2—THIO—IMIDAZOLE RESIN FOR Rh（Ⅲ）AND SEPARATION OF Rh（Ⅲ）WITH COMMON METAL IONS BY USING MTIR

The sorption behavior of N-methyl-2-thio-imidazole resin(MTIR) for Rh(Ⅲ） was investigated.The optmum sorption condition of MTIR for Rh(Ⅲ）,sorption rate t1/2=84min,sorption capacity 1.37mmol Rh(Ⅲ）/g MTIR,[140.5mg Rh(Ⅲ）/g MTIR],sorption molar ratio 0.34Rh(Ⅲ）/functional group,distribution coefficient D=2.5×10^3mg·g^-1 were determined.The sorption selectivity of MTIR for Rh(Ⅲ）in the presence of common metal ions,Fe^3+,Co^2+,Ni^2+ and Cu^2+ was examined.Rh(Ⅲ） adsorbed on MTIR can be eluted quantitatively by using a mixed solution composed of 20% thio-urea-acetone:6mol HCl.dm^-3(1:1vol.) used as an eluent.Rh(Ⅲ） can be separated from the mixture of Rh(Ⅲ） and Fe^3+,Co^2+,Ni^2+,Cu^2+ by using D72 resin and MTIR successively.     

D201×4树脂对金(III)的吸附

Sorption behavior and mechanism of D201×4 resin for Au(III) were investigated. D201×4 resin has a good adsorptivity for Au(III) in HAc-NaAc medium at pH value of 2.63. The statically saturated Au(III) sorption capacity was 689.11 mg·g^-1 resin. The Au(III) adsorbed on D201×4 resin could be eluted by 10%NH₂CSNH₂-1 mol·L^-1 HCl(1∶1) and the elution rate was 92.2%.The adsorption of Au(III) on D201×4 follows the Freundlich isotherm. The ΔH of the adsorption was 11.03 kJ·mol^-1. The sorption rate constant was 5.42×10^-5 s^-1. The activation energy was 13.26 kJ·mol^-1. The molar coordination ratio of the functional group of D201×4 to Au(III) was about 1:1. The adsorption mechanism of resin for Au(III) was suggested according to chemical analysis and IR spectraoscopy results.     

Theoretical studies on the structures and isomerization of the LiSiF_3 system

Various possible isomers of LiSiF_3 system and isomerization between them have been studied at G2(MP2) level using ab initio calculations. The relative energies of four minimum points on the potential energy surface are -128.6, -194.3, -12.7 and -122.8 kJ/mol (taking the sum of the energies of LiF and SiF_2 as zero) . The structural energy of the four-membered ring that contains three F-Si-F-Li four-membered rings with C_(3v) symmetry is the lowest. The highest potential barrier for the isomerization of the remaining three-or four-membered structure is 12.5 kJ/mol.     

Quantum chemical study of chlorine-dissociation of oxalyl chloride (ClCO)_2→2Cl+2CO

It is very difficult to study the phenomenon that molecules are decomposed into several pho-tofragments by UV light, as the energy of lamp-house is insufficient. But the bond energy in oxa-lyl chloride is relatively low, for example, D0(ClCOCO-Cl) = 313.92 kJ/mol[1], D0(ClCO-CO) = 35.53 kJ/mol, and D0(Cl-CO) = 27.17 kJ/mol[2], so, oxalyl chloride, as a typical system for the study of multi-channel dissociation, can be dissociated into the four fragments Cl+Cl+CO+CO by the proper UV …     

Density Functional Calculations on a Double Hydrogen-bonded Dimer

Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of o-hydroxybenzoic acid were carried out at the B3LYP/6-31G^* level. The optimized geometry of the dimer closely resembles that of the crystal. The calculated results show that the total energy of the dimer is much lower than the sum energies of the two monomers, and the average strength of the double hydrogen bonds is about 38.37 kJ/mol. In order to probe the origin of the interactions in the dimer, natural bond orbital analyses were performed. The thermodynamic properties of the title compound at different temperatures have also been calculated on the basis of vibrational analyses and ΔGT, the change of Gibbs free energy for the aggregation from monomer to the dimmer, is 26.47 kJ/mol at 298.15 K and 0.1MPa, implying the spontaneous process of forming the dimer. The correlation graphics of Sm^0 Hm^0 and temperatures is depicted.     

Kinetics and Thermodynamics of Adsorption of VB12 onto Mesoporous Carbon Coated with PMMA

Ordered mesoporous carbons CMK-3, CMK-1 coated with poly(methyl methacrylate)(PMMA)(CMK-3- PMMA and CMK-1-PMMA) and pristine mesoporous carbons CMK-3, CMK-1 were employed to adsorb vitamin B12(VB12) from water solution. Adsorption isotherm and kinetics of adsorption were investigated via batch experi- ments. It was found that the adsorption capacity of VB12 at 30, 40 and 50 °C can reach 688.2, 572.4 and 428.7 mg/g, respectively. The adsorption isotherm can be described by Langmuir model. The pseudo first- and second-order kinetic models were employed to fit the dynamic adsorption. It was found that the dynamic adsorption follows the pseudo second-order model. The thermodynamic equilibrium coefficients obtained at different temperatures were used to evaluate the thermodynamic constants ΔG0, ΔH0 and ΔS0. The negative value of Gibbs free energy, ΔG0 indicates that the adsorption occurred via a spontaneous process. The increase in the value of –ΔG0 with increasing temperature indicates that higher temperatures were favourable to the sorption process. The enthalpy values of ΔH040 kJ/mol(66.36 kJ/mol and 56.43 kJ/mol) for CMK-3-PMMA and CMK-1-PMMA confirm that chemisorption were involved in the adsorption process. This is consistent with the IR spectra and is another evidence for the formation of hydrogen bond between PMMA in the pore of CMK-3 and VB12.     

SYNTHESIS OF MACROPOROUS HUMIC ACID RESINS AND THEIR CHELATING PROPERTIES FOR HEAVY METAL IONS

Macroporous HA resins (HAR) can be prepared in pearl form by grafting HA onto crosslinked PS through azo or through ester and / or ether linkages. At pH 13 and the HA / PSNH_2 weight ratio 0.7—1.0, PSN_2~+-Cl~-couples with HA and results in the formation of a7o-type HA resin (HAR-A), which shows good adsorbility towards heavy metal ions. The Cu~(2+) sorption capacity of ester / ether type humic acid resin (HAR-E) is increased by lengthening the reaction time of HA and PSCH_2Cl. The structure of HAR is discussed on the basis of the IR spectra. The sorption capacity of HAR-A is 1.01 mmol / g for Cd~(2+) and 0.6—0.53 mmol/g for Ni~(2+), Mn~(2+), Cu~(2+), Co~(3+) and Zn~(2+). respectively. The calculated distribution coefficients of heavy metal ions on HAR-A can be arranged in the following order: Cu~(2+)(8.7×10~3)>Cd~(2+) (3.8×10~2)>Zn~(2+)(2.4×10~2)>Ni~(2+)(1.8×10~2)>Mn~(2+)(4.9×10). At pH 6.5, Cu~(2+), Cd~(2+), Ni~(2+), Mn~(2+) can be quantitatively adsorbed by HAR-A and completely eluted with 1N HNO_3. HAR-A can be regenerated and reused. Trace quantities of the above-mentioned heavy metal ions in four samples of the natural occurring water and one sample of the tap water were analyzed by using HAR-A.     

Synthesis and Thermal Behavior of 1,8-Dihydroxy- 4,5-dinitroanthraquinone Manganese Salt

A novel energetic combustion catalyst, 1,8-dihydroxy-4,5-dinitroanthraquinone manganese salt （DHDNEMn）, was synthesized by virtue of the metathesis reaction in a yield of 91%, and its structure was characterized by IR, element analysis and differential scanning calorimetry（DSC）. The thermal decomposition reaction kinetics was studied by means of different heating rate DSC. The results show that the apparent activation energy and pre-exponential factor of the exothermic decomposition reaction of DHDNEMn obtained by Kissinger＇s method are 162.3 kJ/mol and 1011.8 s^-1, respectively. The kinetic equation of major exothermic decomposition reaction of DHDNEMn is dα/dT= 10^118/β 2/5（1-α）[-ln（1-α）[-ln（1-α）]^3/5 exp（-1.623×10^5/RT）. The entropy of activation（△S^≠）, enthalpy of activation（△H^≠） and free energy of activation（A△G^≠） of the first thermal decomposition are -24.49 J·mol^-1·K^-1, 185.20 kJ/mol and 199.29 kJ/mol（T=575.5 K）, respectively. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） are 562.9 and 580.0 K, respectively. The above-mentioned information on the thermal behavior is quite useful for analyzing and evaluating the stability and thermal safety of DHDNEMn.     

Thermal Degradation Kinetics of N,N＇-Di（diethoxythiophosphoryl）-1,4-phenylenediamine

The non-isothermal degradation kinetics of N,N＇-di（diethoxythiophosphoryl）-1,4-phenylenediamine in N2 was studied by TG-DTG techniques.The kinetic parameters,including the activation energy and pre-exponential factor of the degradation process for the title compound were calculated by means of the Kissinger and Flynn-Wall-Ozawa（FWO）method and the thermal degradation mechanism of the title compound was also studied with the Satava-Sestak methods.The results indicate that the activation energy and pre-exponential factor are 152.61 kJ/mol and 9.06×101 4s -1with the Kissinger method and 154.08 kJ/mol with the Flynn-Wall-Ozawa method,respectively.It has been shown that the degradation of the title compound follows a kinetic model of one-dimensional diffusion or parabolic law,the kinetic function is G（α）=α2and the reaction order is n=2.     

ADSORPTION OF 1,2,4-ACID BY WEAKLY BASIC RESIN： ISOTHERMS, THERMODYNAMICS AND KINETICS

The adsorption properties, including the adsorption isotherms, thermodynamics and kinetics, of l-amino-2-naphthol-4-sulfonic acid (1,2,4-acid) onto weakly basic resin ND900 are investigated. Both the Langmuir and Freundlich equations can give a good fit to the adsorption isotherms, which indicates an endothermic and a favorable adsorption in our study range. A high yield in elimination of about 45.21%-97.28% is obtained for the tested adsorption systems. The capacity and affinity of the adsorption increase with temperature, due to the phenomena of “solvent-motivated” effects. The value of ΔH is 51.59 kJ/mol, which indicates a chemical adsorption and then expects the poor desorption property of ND900. The negative value of ΔG indicates the spontaneous nature of the adsorption process, and the positive value of ΔS shows the increased randomness at the solid/solution interface during the adsorption process. The value of the adsorption rate constant lower than 0.013 min^-1 is indicative of a slow adsorption rate. The intra-particle diffusion must be one of the rate limiting steps.     

Ab initio potential energy surface and excited vibrational states for the electronic ground state of Li_2H

A 285-pomt multi-reference configuration-interaction involving single and double excitations ( MRS DCI) potential energy surface for the electronic ground state of L12H is determined by using 6-311G (2df,2pd)basis set.A Simons-Parr-Finlan polynomial expansion is used to fit the discrete surface with a x2 of 4.64×106 The equn librium geometry occurs at Rc=0.172 nm and,LiHL1=94.10°.The dissociation energy for reaction I2H(2A)→L12(1∑g)+H(2S) is 243.910 kJ/mol,and that for reaction L12H(2A')→HL1(1∑) + L1(2S) is 106.445 kl/mol The inversion barrier height is 50.388 kj/mol.The vibrational energy levels are calculated using the discrete variable representation (DVR) method.