Authors:M. L. Zhang, M. L. Zhang, M. L. Zhang, A. Ren, A. Ren, A. Ren, D. Shao, D. Shao, D. Shao, X. Wang, X. Wang, and X. Wang
The sorption and desorption of radionuclide 90Sr2+were investigated on untreated calcareous soil and two treated soils to remove organic matter and calcium carbonate using
batch technique. The experiments were carried out at ambient condition, pH 7.8±0.1 and in the presence of 0.001M NaCl. Effects
of fulvic acid and ionic strength on the sorption of 90Sr2+on calcareous soil were also studied. It was found that the sorption isotherms are linear in the strontium concentration range
used herein, and the sorption of 90Sr2+on the calcareous soil can be described as a reversible sorption process and the sorption mechanism is mainly ion-exchange.
The sorption is dependent on ionic strength, and fulvic acid enhances the sorption of 90Sr2+on calcareous soil. Organic matter present in the calcareous soil is a significant trap of 90Sr2+and is responsible for the sorption.
A novel complex, [Pr(5-nip)(phen)(NO3)(DMF)]
(5-nip: 5-nitroisophthalic acid; phen: 1,10-phenanthroline, DMF: N,N-dimethylformamide),
was prepared and characterized by single crystal X-ray diffraction, elemental
analysis, IR spectrum and DTG-DSC techniques. The results show that the crystal
is monoclinic, space group P2(1)/n with a=11.0876(6) Å, b=12.8739(7)
Å, c=16.9994(8) Å; β=91.193(4)°, Z=4, Dc=1.822
Mg m–3, F(000)=1320.
Each Pr(III) ion is nine-coordinated by one chelating bidentate and two monodentate
bridging carboxylate groups, one chelating bidentate nitryl group, one DMF
molecule and one 1,10-phenanthroline molecule. The complex is constructed
with one-dimensional ribbons featuring dinuclear units and the one-dimensional
ribbons are further assembled into two-dimensional networks by strong π–π
stacking interactions. The complex has high stability up to 500°C. The
enthalpy change of formation of the compound in DMF was measured using an
RD496-III type microcalorimeter with the value of –9.214±0.173
The decomposition kinetics of reference calcite and three ultra-fine samples with different morphologies are investigated.
The kinetic parameters and rate equation are obtained according to the methods reported in our previous studies. Compared
with the reference calcite, a considerable diminution of the activation energy Ea up to 70–80 kJ mol−1 is observed in the case of three ultra-fine samples. There are also some distinct differences concerning the activation energy
of each of the ultra-fine sample. This may have something to do with the particle morphology revealed by TEM and SEM measurements.
XRD measurements of four calcite samples show that large strain exists in the crystal lattice in the case of ultra-fine calcite
samples. This may give a reason to their abnormal decomposition behavior.
Authors:Sh. Yu, X. Li, A. Ren, D. Shao, Ch. Chen, and X. Wang
removal of heavy metal ion Co(II) from aqueous solution was studied usingg-Al2O3
by batch technique. The experiments were performed at T=20±2 °C, in 0.01M
NaNO3 solutions and under aerobic conditions. The effect of pH,
ionic strength, fulvic acid (FA) and alumina amount on the sorption of Co(II)
on alumina were also investigated. The pH affected the sorption of Co(II)
significantly as compared with the effect of FA and ionic strength. The results
indicated that strong chemical bonds are formed between Co(II) and functional
groups of the bare or FA coated alumina, and a precipitation of Co(II) takes
place on the alumina surface, induced by a transition from the adsorption to
surface. The addition sequences of Co/FA on Co(II) sorption were also studied:
the sorption of Co(II) in the ternary system was found independent of addition
Authors:S. Yu, A. Ren, J. Cheng, X. Song, C. Chen, and X. Wang
Effects of pH, ionic strength and fulvic acid on sorption of radiocobalt on montmorillonite and its Al-pillared and cross-linked
samples were studied using batch technique. The results indicate that the sorption of cobalt is strongly dependent on pH values
and independent of ionic strength. Fulvic acid enhances the sorption of cobalt slightly at low pH, but has no influence at
high pH values. Surface complexation is considered the main mechanism of cobalt sorption to montmorillonite. The sequences
of FA/Co2+ additions to the system did not affect cobalt sorption.
Authors:X. Han, Y. Hu, Z. Lin, S. Li, F. Zhao, Z. Liu, J. Yi, L. Zhang, and X. Ren
Effects of fullerenes including FS, EFS and pure C60 on thermal behaviors of polyethylene glycol (PEG) have been studied by employing thermogravimetry-differential thermogravimetry
(TG-DTG), differential scanning calorimeter (DSC) and off-line furnace-type pyrolysis-gas chromatography/mass spectrometry
(Py-GC/MS). The products were collected by Cambridge filter pad which was widely used in analyzing the combustion products
of cigarette. The results showed that the addition of fullerenes obviously restrained the thermal decomposition of PEG. The
initial decomposition temperatures (IDT) and maximum decomposition peak temperatures (MDT) were evidently postponed by the
addition of fullerenes. Pyrolysis products with one or two hydroxyl end groups obviously increased with the addition of 10%
C60. The reasons of the changes were discussed from the aspects of reaction mechanisms.
Authors:X. Han, Y. Sun, T. Wang, Zh. Lin, Sh. Li, F. Zhao, Z. Liu, J. Yi, and X. Ren
The effects of fullerenes, including fellerene soot (FS), extracted fullerene soot (EFS) and pure C60 on the thermal decomposition of ammonium perchlorate (AP) compared with traditional carbon black (CB) catalyst has been studied
by employing thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR) and ignition temperature
experiments. The results showed that the addition of CB and FS to AP reduced the activation energy as well as the temperature
at maximum decomposition rate, but that of EFS and pure C60 had little effect on the thermal decomposition of AP, and among all catalysts, FS was the best one.
Authors:A. Ren, S. Yu, J. Han, P. Chang, C. Chen, J. Chen, and X. Wang
Humic substances have attracted great interest in the investigation of metal ion behavior in the environment because of their
special properties. Sorption and complexation of Pb2+ on MX-80 bentonite, LA bentonite, alumina and silica as a function of pH were studied in the presence and absence of fulvic
acid (FA). The experiments were carried out in 0.01M and 0.001M NaNO3 solutions under ambient conditions. The results indicate that sorption of Pb2+ on the solid samples is strongly dependent on pH and FA. The sorption of Pb2+ is not influenced drastically by ionic strength. The nature of minerals/oxides, nature of humic substances and the composition
of the solution are important factors in the behavior of metal ions in the environment. The results also indicate that FA
has a positive effect on Pb2+ sorption at low and a negative effect at high pH values, and the results are discussed in the comparative complexation between
FA-Pb2+ and Pb2+-minerals.
Authors:S. Xiao, J. Zhang, X. Li, L. Ye, H. Gu, and N. Ren
A ternary binuclear complex of dysprosium chloride hexahydrate with m-nitrobenzoic acid and 1,10-phenanthroline, [Dy(m-NBA)3phen]2·4H2O (m-NBA: m-nitrobenzoate; phen: 1,10-phenanthroline) was synthesized. The dissolution enthalpies of [2phen·H2O(s)], [6m-HNBA(s)], [2DyCl3·6H2O(s)], and [Dy(m-NBA)3phen]2·4H2O(s) in the calorimetric solvent (VDMSO:VMeOH = 3:2) were determined by the solution–reaction isoperibol calorimeter at 298.15 K to be