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81.
82.
Engineered zeolite was produced from oil shale ash by reaction with sodium hydroxide in a closed vessel reactor. This adsorbent was used for removal of copper ions from aqueous solution. The maximum adsorption capacity was 504.6 mg Cu2+/g zeolite. Kinetic studies showed that the rate of adsorption of copper is increased with increasing the solution pH and temperature, quantity of the zeolite and agitation speed. The kinetic data were fitted to homogeneous micropore model and found that the mass transfer coefficient and diffusivity of the Cu2+ are directly affected by the kinetic parameters. The increase in solution concentration will decrease the mass transfer coefficient while diffusivity is increased. 相似文献
83.
Daniel G. Strawn 《Environmental pollution (Barking, Essex : 1987)》2009,157(10):2813-2821
Bioavailability of Cu in the soil is a function of its speciation. In this paper we investigated Cu speciation in six soils using X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and synchrotron-based micro X-ray fluorescence (μ-XRF). The XANES and EXAFS spectra in all of the soils were the same. μ-XRF results indicated that the majority of the Cu particles in the soils were not associated with calcium carbonates, Fe oxides, or Cu sulfates. Principal component analysis and target transform of the XANES and EXAFS spectra suggested that Cu adsorbed on humic acid (HA) was an acceptable match. Thus it appears that Cu in all of the soils is primarily associated with soil organic matter (SOM). Theoretical fitting of the molecular structure in the soil EXAFS spectra revealed that the Cu in the soils existed as Cu atoms bound in a bidentate complex to O or N functional groups. 相似文献
84.
Adsorption of lambda-cyhalothrin and cypermethrin on two typical Chinese soils as affected by copper
Jun Liu Xiaomeng Lü Jimin Xie Yafei Chu Cheng Sun Qian Wang 《Environmental science and pollution research international》2009,16(4):414-422
Background, aim, and scope Pesticides and heavy metals pollution in soil environment has become a serious problem in many countries including China.
Repeated applications of bordeaux mixture (a blend of copper sulfate and calcium hydroxide) and pyrethroid (Pys) insecticides
have led to elevated copper (Cu) and Pys concentrations in vineyard surface soils. However, few studies focused on the interaction
of Pys and heavy metals in the soil environment. Our previous studies had indicated the combined effect of cypermethrin (CPM)
and Cu on soil catalase activity. Also, we had suggested that the addition of Cu could catalyze photo-degradation of CPM and
lambda-cyhalothrin (λ-CHT) in aqueous solution and restrain their degradation in soil. To better understand the potential
influence of Cu on the fate of Pys in the soil environment, the aim of the present work was to examine the effect of Cu on
the adsorption of λ-CHT and CPM on two typical Chinese soils with different soil characteristics, which was one of the key
processes controlling the fate of Pys, and to provide more information about the potential ecological risk of chemicals on
the soil ecosystem. Fourier transform infrared and point charges analysis using the MOPAC program of the Gaussian system were
also used to reveal the probable adsorption mechanism of λ-CHT and CPM on soils.
Materials and methods Two vineyard soils with different properties were chosen as experimental samples. They were sampled from 0 to 10 cm, dried,
and sieved to 2 mm. Each soil was spiked with copper sulfate solution to obtain the following total soil Cu concentrations:
100, 200, 400, 800, and 1,600 mg·kg−1. The treated soils were incubated for 2 weeks and then dried at 20°C. For each soil sample and at each soil Cu concentration,
the adsorption of λ-CHT and CPM was measured using a batch equilibrium method. The concentration of λ-CHT was determined by
HPLC, and the amount of λ-CHT and CPM adsorbed by the soil sample at equilibrium was determined by the difference between
the initial and equilibrium concentrations in solution corrected by the blank adsorption measurement.
Results Without the addition of Cu, the adsorption of λ-CHT and CPM on Black soil is greater than that on Red soil, while the adsorption
of λ-CHT on both soils is significantly stronger than that of CPM. As the soil Cu concentration increased from 19 (or 18;
background) to 1,600 mg·kg−1, the adsorption coefficient (K
d) of λ-CHT decreased from 12.2 to 5.9 L·kg−1 for Red soil, and from 26.1 to 16.8 L·kg−1 for Black soil, whereas the CPM adsorption coefficient in both soils decreased nearly by 100% (K
d decreased from 9.4 to 0.2 L·kg−1 for Red soil and from 16.2 to 0.5 L·kg−1 for Black soil).
Discussion Pys adsorption is a surface phenomenon which depends on the surface area and the organic matter content. Thus, the Black soil,
having higher organic matter and greater surface area than that of the Red soil, show greater adsorption affinity to λ-CHT
and CPM. In our study, the different adsorption affinity of the two Pys was obtained, which was probably attributed to differences
with respect to their physical–chemical properties. Further comparison upon the two Pys was conducted. The point charges of
halogen atoms in the λ-CHT and CPM were calculated, the differences of which probably lead to the fact that λ-CHT has a stronger
binding capacity to soils than CPM. Also, FTIR spectra show that competitive adsorption occurs between CPM and Cu for the
same adsorption sites, which is responsible for the obtained suppression of CPM adsorption affected by Cu.
Conclusions Lambda-cyhalothrin shows a significantly stronger adsorption than cypermethrin on both soils. This phenomenon may be due to
several reasons: (1) λ-CHT has lower solubility and a higher octanol–water partition coefficient value than CPM; (2) λ-CHT
consists of specific isomers, whereas CPM is mixtures of eight different isomers; (3) the chlorine and fluorine atoms in the
λ-CHT have a negative point charge, whereas the chlorine atoms in the CPM have a positive point charge. As the soil Cu concentrations
increased from 19 (or 18) mg·kg−1 to 1,600 mg·kg−1, the adsorption coefficient of λ-CHT and CPM decreased on both soils. This is mainly due to a competition between Cu and
Pys for occupying the adsorption sites on soils. The information from this study have important implications for vineyard
and orchard soils, which often contain elevated levels of Cu and Pys. These results are also useful in assessing the environmental
fate and health effect of λ-CHT and CPM.
Recommendations and perspectives It is important for environmental scientists and engineers to get a better understanding of soil–metal–organic contaminant
interactions. However, pesticide adsorption involves complex processes, and shortcomings in understanding them still restrict
the ability to predict the fate and behavior of pesticide. Therefore, considerable research should be carried out to understand
the mechanism of interaction between Pys and heavy metal on soils clearly. 相似文献
85.
Cu accumulation and depuration in various tissues of the crayfish Astacus leptodactylus was investigated. Adult specimens were exposed to 0.5, 2.5 and 5.0 mg Cu/L under static conditions for three weeks. At the
end of the 3rd week the specimens were divided into three groups and left in dechlorinated water for either 1, 2 or 3 weeks
for depuration. After 7, 14 and 21 days, four crayfish from each group were instantaneously sacrificed. All crayfish were
dissected into their hepatopancreas, gill, abdominal muscle and exoskeleton tissues for evaluation of Cu accumulation in each.
The following accumulation pattern was obtained in decreasing order; hepatopancreas > gills > exoskeleton > abdominal muscles
with values of 94.13, 84.86, 66.13 and 11.43 mg/L, respectively. The observed Cu depuration throughout the study was found
to be time-dependent. Based on the present work we conclude that crayfish has a great potential for rapid accumulation and
depuration of Cu in fresh water. 相似文献
86.
Reddy KJ Kumar JR Narayana SL Ramachandraiah C Thriveni T Reddy AV 《Environmental monitoring and assessment》2007,124(1-3):309-320
N-ethyl-3-carbazolecarboxaldehyde-3-thio- semicarbazone (ECCT) as an new analytical reagent used for the development of a
highly sensitive extractive spectrophotometric method for the determination of copper(II). The ECCT forms a greenish-yellow
colored 1:1 (M:L) complex with copper(II) at pH 3.0, which is well extracted into n-butanol and shows maximum absorbance at
380nm. The color of the complex is stable for more than forty eight hours. The system obey Beer's law in the range 0.4–3.6
with 2.243 × 104lmol−1cm−1, 2.83 × 10-3μgcm−2 molar absorptivity and Sandell's sensitivity respectively. The regression coefficient is 0.412 with 0.99 correlation coefficient.
The precision and accuracy of the method was checked by finding the relative standard deviation (0.422%). This developed method
has been successfully employed for the determination of copper(II) in environmental and pharmaceutical samples. The method
is evaluated by analyzing samples from the bureau of analyzed samples (BCS 233, 266, 216/1, 207 and 179) and by inter comparison
of experimental values using AAS. 相似文献
87.
Little is known about how the growth of trihalomethanes (THMs) in drinking water is affected in copper pipe. The formation of THMs and chlorine consumption in copper pipe under stagnant flow conditions were investigated. Experiments for the same water held in glass bottles were performed for comparison. Results showed that although THMs levels firstly increased in the presence of chlorine in copper pipe, faster decay of chlorine as compared to the glass bottle affected the rate of THMs formation. The analysis of water phase was supplemented by surface analysis of corrosion scales using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDX). The results showed the scales on the pipe surface mainly consisted of Cu2O, CuO and Cu(OH)2 or CuCO3. Designed experiments confirmed that the fast depletion of chlorine in copper pipe was mainly due to effect of Cu2O, CuO in corrosion scales on copper pipe. Although copper(II) and copper oxides showed effect on THMs formation, the rapid consumption of chlorine due to copper oxide made THM levels lower than that in glass bottles after 4 h. The transformations of CF, DCBM and CDBM to BF were accelerated in the presence of copper(II), cupric oxide and cuprous oxide. The effect of pH on THMs formation was influenced by effect of pH on corrosion of copper pipe. When pH was below 7, THMs levels in copper pipe was higher as compared to glass bottle, but lower when pH was above 7. 相似文献
88.
89.
Ghauch A Turnar C Fachinger C Rima J Charef A Suptil J Martin-Bouyer M 《Chemosphere》2000,40(12):1327-1333
Diffuse reflectance spectroscopy can be successfully used for the quantitative determination of small amounts of pollutants like metals. The remission function was found to be linearly proportional to the concentration, when we applied the Kubelka–Munk equation. The color reactions of Cu(II), Co(II), and Ni(II) with dithiooxamide, were realised on filter paper. Reaction between Fe(III) and ammonium thiocyanate was realized on filter paper and gelatine matrix. All measurements were accomplished with a laboratory-constructed reflectometer. We have obtained a calibration curve by plotting the optical density of reflectance AR vs log of the mol l−1 concentration. Limits of detection at the 10−4 M level were estimated for all the compounds. Linear dynamic range extend over one order of magnitude and shows the potential of device for the quantitative analysis of environmental pollutants. 相似文献
90.
Shigehisa Endoh Kenzo Takahashi Jae-Ryeong Lee Hitoshi Ohya 《Journal of Material Cycles and Waste Management》2006,8(1):88-94
Enforcement of the Automobile Recycling Law in Japan requires utilization of automobile shredder residue (ASR). However, the
high contents of copper (∼5%) and chlorine (∼1%) in ASR stand in the way of practical application. We studied methods for
the removal of copper and chlorine from ASR so that it could be utilized as a fuel. By compression of the ASR for solidification
with an extruder, the polyvinylchloride (PVC) that covered electrical cables was softened and stripped from the copper wire.
The solidified ASR was comminuted with cutter mills and classified by dry density separation. The copper content of the obtained
light products was 0.2%–0.5%. Furthermore, we studied the possibility of dechlorination of the ASR by mechanochemical (MC)
activation. The light product of the ASR was milled with CaO or CaCO3. The chlorine content decreased to about one-tenth of the original value after MC activation over 8 h. Therefore, the combined
processing of softening–stripping and comminution liberated the PVC-covered cables and decreased the copper content of the
ASR. In addition, dechlorination of the ASR was also possible by MC activation with the addition of calcium compounds. 相似文献