[Response of FTIR and Raman Spectra on Cell Wall of Calendula Officinalis Seedlings Roots to the Co-Contamination Stress of Lead and Cadmium in Loess].

Phytoremediation is a novel method with great potential for site remediation contaminated by heavy metals in future. The cell wall of plant roots is significant to affect the remediation efficiency, for it is related to the multi-interface of heavy metals, pedosphere and plant. The relationship between cell wall of plant and heavy metals is complicated, containing the reaction behavior of physical chemistry, physiology and biochemistry. At present, the spectral technologies are not adequately used to investigate the in-situ response characteristics between cell wall of plant roots and heavy metals. The Calendula officinalis seedlings, the remediation plant in loess, were used as experimental sampleswhile the root characteristic variation was revealed on cell wall. The approaches of X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectra were applied to analyze the response effect of cell wall to lead/cadmium stress. The results showed: the cell wall appears to be shrinking, and certain amounts of dark particles appear on cell wall. The contents of lead/cadmium increase greatly as shown from XRF, while the representative crystals of lead/cadmium are hardly detected. The absorbance peak at 3 416 cm-1 indicates the coordination effect between lead/cadmium and ­OH in FTIR, and the movement of absorbance peaks, from 1 701 to 1 736 cm-1 and 1 593 to 1 618 cm-1, respectively, indicates the different characteristics of protein in cell wall of Calendula officinalis seedlings roots under lead/cadmium stress. The Raman intensity of absorbance peak at 2 960 cm-1 increases under lead/cadmium stress, and it proves the changes on arranging directions of cellulose molecules in cell wall samples. The components (Pectin, protein, cellulose, etc.) and functional groups (­OH, N­H, CO, etc.) of cell wall play an important role in the resistance process of cell wall derived from Calendula officinalis seedlings roots to the stress of lead/cadmium in loess.

[Study on the Mechanism to Ease the Leaching Effect of Nutrient in the Multi-Contaminated Loess Washing Process with the Addition of Anion Adsorbent(â ¡)].

The soil washing technology is commonly used to remediate contaminated soils because of its advantages of low cost, ease handling and environmental-friendly. However, it should be noticed that the nutrient might leach simultaneously from soil in the washing process, and the technical solution of the issue will greatly accelerate the application process of washing technology in site remediation. This paper aims to reveal the regulating mechanism of synthesized anion adsorbent from straw on nutrient leaching potential through approaches of adsorption equilibrium models (isotherms and kinetics) and spectral analysis instruments (SEM and FTIR). The results showed: the Langmuir isotherm and pseudo second order kinetic equation fit better the adsorption behavior of nitrate and phosphate. The maximum adsorption capacity (qm), calculated with Langmuir isotherm, are 7.507 5 and 4.194 6 mg·g-1, respectively, and the reaction belongs to the monolayer and favorable adsorption with chemical adsorption the rate-determining step. The activation energy of adsorption for nitrate and phosphate at 298 K are 42.25 and 39.38 kJ·mol-1, respectively, and the reaction is spontaneous and endothermic. The purified water and KOH solution are effective for the regeneration of anion adsorbent, the desorption effect is better for the assistance of ultrasonic sound and longer desorption time. The surface of anion adsorbent after adsorption is covered with particles, while less spray-like component appears after desorption with purified water. The movement of vibration peaks in FTIR spectra indicates the effect of electrostatic interaction in the reaction. The adsorption of nitrate and phosphate on anion adsorbent involves simultaneously the effects of physical and chemical adsorption.

[FTIR Analysis of Secondary Abiotic Stress Response of Calendula Officinalis Seedlings to Lead and Cadmium in Multi-Contaminated Loess].

As an environmentally-friendly technology attracting great attention from current researchers, phytoremediation is significant for site remediation contaminated by heavy metals. The plant will appear related physiological response to reduce direct harm caused by the stress of heavy metals. The microscale behavior is always multi-dimensional and difficult to detect. The advanced instruments are effective to resolve the scientific issues, while the related researches are seldom investigated. Taking calendula officinalis seedlings as experimental samples, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) were applied to compare the surface characteristics and functional groups variation, respectively. The response process and tolerance mechanism of calendula officinalis seedlings to lead and cadmium stress were further analyzed. The results showed: with the increasing concentration of lead and cadmium in loess, the calyptra of calendula officinalis seedlings become bending and wilting; the amount of root hairs decreases greatly while no significant variations of aerial parts are found on surface characteristics. The stress of lead and cadmium are responsible for the difference of FTIR spectra of Calendula officinalis seedlings. The peak absorbance at 3 573 cm-1 decreases and the peak becomes more complex with the increasing contents of lead and cadmium. It might be the coordination effect between lead/cadmium and hydroxyl, which affects the synthesis and secretion of organic matters. The movement of C­H vibration peak is associated with the lipid oxidationwhile the changes at 1 631 and 1 574 cm-1 suggest the protein component differences. The shifting peak at 1 385 cm-1 might be associated with the methylation of pectin and lipid, and the behavior is positive for the adaption process of calendula officinalis seedlings to lead and cadmium stress. The FTIR spectra are effective to reveal the phytoremediation mechanism on heavy metals contamination in pedosphere.

[Determination of Lead and Cadmium in Calendula Officinalis Seedlings for Phytoremediation of Multi-Contaminated Loess by Using Flame Atomic Absorption Spectrometry with Wet Digestion].

Atomic absorption spectrometry (AAS) is widely used in the analysis and detection of heavy metals. The optimal operation conditions on metals detection are important for the stabilization and repeatability of scientific research, which affects the expected investigation objectives greatly. Thus, it becomes a key issue to establish appropriate detection methods in scientific works. Calendula officinalis was used for lead/cadmium remediation in contaminated loess, and the flame atomic absorption spectrometry (FAAS) with wet digestion was applied to analyze the contents of lead/cadmium in Calendula officinalis seedlings. The investigation data was further studied to reveal the bioaccumulation efficiency of lead/cadmium in Calendula officinalis seedlings. The results showed: the limits of detection are 0.104 and 0.007 mg·L-1 for lead and cadmium; the recovery rates of lead and cadmium are from 94.33% to 110.78% and 97.73% to 107.50% respectively. The relative standard deviations (RSD) are between 4.11% and 4.75% for lead while between 1.11% and 2.77% for cadmium，and It's been proved that the method is accurate and reliable. The low accumulation efficiency of lead with Calendula officinalis seedlings might be related to the electronegativity of lead while the growth period of calendula officinalis seedlings and environmental factors. The accumulation content of cadmium is 104.85 mg·kg-1 with cadmium concentration of 50 mg·kg-1. The co-existing of lead in loess is positive for cadmium accumulation by Calendula officinalis seedlings, and the synergistic effect might work in the process. The established detection method is effective for quantitative analysis of lead and cadmium in calendula officinalis seedlings and significant for future research.

[Spectral Evidence of In-Situ Regulatory Mechanisms on Chemical Speciation of Lead/Cadmium Affected by Dissolved Organic Matter Extracted from Rhizosphere Loess of Calendula Officinalis Seedling].

The various characteristics of DOM have great impact on the transformation process of contaminants in soil due to the generation of the feedback regulation in cycles of plant, Rhizosphere soil and environmental contaminants. Currently, more attention was paid on contaminants behaviors of adsorption, transformation, accumulation and detoxification than DOM derived from Rhizosphere soil. The chemical speciation of lead/cadmium and growth efficiency related variations were revealed in the growth process of Calendula officinalis seedlings, and the spectral characteristics of DOM in Rhizosphere loess were discussed with UV, FT-IR and 3D-EEMs spectra. The results showed: the dominant contents of lead/cadmium are in residual and exchangeable speciation, and the exchangeable contents increase greatly after the growth of Calendula officinalis seedlings. It causes negative effects on the height and emergency rate of Calendula officinalis seedlings with lead/cadmium, and the Calendula officinalis is able to positively improve loess characteristics. The root of Calendula officinalis appears to be longer, thinner and flexuous. The maximum absorption band of DOM in UV spectra locates in 200~240 nm, and the sharper and greater intensity of peaks can be detected under lead/cadmium stress. The absorption peaks in FT-IR spectra move from 3 444 and 1 637 to 3 440 and 1 645 cm-1, respectively, indicating the combination effects between metal ions and functional groups of­OH and CO. The dominant fluorescence peaks of DOM are found to be aroundλex/em=240/430, described as fulvic-acid like components, and metals in loess affect more on peaks intensity than locations. The characteristics of DOM in Rhizosphere loess of Calendula officinalis seedlings contain much micro-eco-environmental information, and the spectral approaches are efficient to reveal the relationship between DOM and chemical speciation of lead/cadmium.

[Spectral Characteristics of Dissolved Organic Matter (DOM) Derived from Water and Sediment in Normal Flow Period of the Intersection Zone of Jing River and Wei River].

As the representative component for eco-environmental researchers, dissolved organic matter (DOM) is playing a significant role for the indication effect on environmental quality and efficiency assessment on remediation approaches. Nowadays, it lacks related investigation on DOM derived from rivers and sediments, and the advanced discussion is in urgent need because of the dynamic variations of experimental target, such as spatial-temporal condition, hydrological condition, environmental condition and research dimension. The spectral approaches, including elemental analysis, ultraviolet spectra (UV), Fourier transform infrared spectroscopy (FT-IR), Raman spectra (Raman), three dimensional excitation emission matrix fluorescence spectroscopy (3D-EEMs) and nuclear magnetic resonance (NMR) were used to reveal the characteristics of DOM derived from water and sediment samples in the intersection zone of Jing River and Wei River (Gaoling District, Xi'an City, Shaanxi Province). The results showed: the ratios of H/C and N/C for DOM in sediment are higher than that of DOM in water, suggesting the saturation degree in DOM from sediment are higher with more content of nitrogen. The UV absorbance of DOM decreases with the increasing of wave length, and obvious absorption region (240～310 nm) appears in DOM from sediment. The functional groups of ­OH, CC and C­O could be found in DOM from FTIR spectra, and the characteristics might be more complicated in sediment for various peak shapes and intensities. The Raman spectra of DOM in water are similar to that of the sediment. The fluorescence peaks of DOM in water are regarded as visible tryptophane-like and UV fulvic-like components, mainly from terrestrial source; while fluorescence peaks of DOM in sediment belong to UV fulvic-like fluorescence without protein-like fluorescence peaks being detected. The principal carbon chains are similar in DOM samples from water and sediment, and the aliphatic characteristics are more obvious for the latter, which contains more carbohydrate-binding hydrogen than aromatic-binding hydrogen and γ-H. It proves that DOM in water mainly comes from terrestrial source, and DOM in sediment is more complicated and fresher. The achievements are significant to reveal the microscopic characteristics and environmental behavior of DOM in representative systems.

[Spectral Analysis of Dissolved Organic Matter of Tannery Wastewater in the Treatment Process].

Tannery industry is one of the major traditional industries and important wastewater sources in China. The existing research mainly focus on the quality of inlet and outlet water, rather than the purification and transformation behavior of dissolved organic matter (DOM) in the treatment process of tannery wastewater. The UV spectra and fluorescence spectroscopy were used to detect the spectral characteristics of water samples in the treatment process, and it is analyzed that the formation process and the linear relationships between total fluorescence intensity and parameters. The results showed: the UV absorbance of DOM in wastewater increased firstly and then decreased with longer wavelength, and the wave peaks were found around the wavelength of 230 nr. The values of A253 /A203 and SUVA254 increased firstly and then decreased, indicating the complex reaction process related to free substituent and aromatic rings. The fluorescence peaks appeared at the regions of λ(ex/em) = 320-350/440- 460 and λ(ex/em) = 270-300/390-420, referred as visible humic-like and visible fulvic-like fluorescence, respectively. With the treatment process of tannery wastewater, the following fluorescence phenomenon were monitored, such as the blue-shift of humic-like fluorescence peak in the hydrolytic acidification tank, the appearance of tryptophan fluorescence peak in the second biochemical pond (λ(ex/em) = 290/340), the weak fluorescence peak in the fourth biochemical pond (λ(ex/em) = 350/520) and the stabilized fluorescence characteristics in the secondary sedimentation tank and water outlet. The achievements are helpful to investigate the degradation and formation behavior of water components, and significant for the fluorescence variation analysis in the treatment system. The removal rate of total fluorescence intensity of tannery wastewater fit better the removal rate of TOC with coefficient of r 0.835 5. The UV spectra and 3D-EEMs are effective to reveal the purification behavior and mechanism of tannery wastewater.

[FTIR and 13C NMR Analysis of Dissolved Organic Matter (DOM) in the Treatment Process of Tannery Wastewater].

Nowadays, the wastewater quantity discharged yearly from tannery industry is around 0. 2 billion t in China. The contaminants of tannery wastewater include macromolecular organic matters, such as grease, fur scraps and collagen, and the alkaline wastewater appears to be of high content of salt and COD. The quality of tannery wastewater is monitored strictly among all kinds of industry wastewater. In the treatment process of tannery wastewater, the quality of inlet and outlet water is generally analyzed. In fact, the transformation behavior of contaminants should be additionally checked to optimize the treatment conditions. Dissolved organic matter (DOM) is commonly existed in water-bodies and helpful to understand the physicochemical characteristics, while the related work should be further studied on tannery wastewater. The approaches of elemental analysis, thermal gravimetric analysis (TG), Fourier infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (13C NMR) were used to reveal the characteristics of DOM in the treatment process of tannery wastewater. The results showed the carbon content of DOM samples increased gradually, atomic ratios of H/C increased firstly and then decreased, indicating the organic matters were decomposed into chain structures firstly, finally forming the component hard to degraded. The pyrolysis process of DOM mainly proceeded in the regions of 110~530 °C (aliphatic compound, protein, etc. ) and 530~800 °C (aromatic ring, single bond of C-C, etc. ). The functional groups of DOM included -OH, -NH2, C=O and so on, and the aromatic substances were detected, shown from FTIR figures, in the later period of the reaction, caused by the metabolism effect of micro-organism. The content of alkoxy-C increased to the maximum in the second biochemical pond, and the minimum content of aromatic-C appeared in the second biochemical pond, suggesting the transformation behavior of carbon functional groups. The investigation on DOM in tannery wastewater is significant to understand the purification mechanism of contaminants in tannery wastewater.

[Spectrum characteristics of leaching components from co-contaminated loess in ex-situ column washing reaction].

Soil contamination is regarded as one of the most serious issues to humanity all over the world. It is statistically believed that over one-fifth of the farmland, that is 20 million ha, is found to be contaminated by heavy metals in China. And the related issues, caused by soil contamination, of food safety, human health and eco-environmental quality attract much attention by public with more serious contamination than before. The technological approach for soil remediation is widely investigated. The technology of soil washing is effective for contaminants removal, while the treatment procedure might lead to component leaching from soil system, harmful for soil fertility, physicochemical properties and ecological functions. The study of spectral characteristics on leaching component is significant for decision-making of contaminated sites remediation and ecological function recovery, while the related investigation seems weaker nowadays. The paper mainly revealed the leaching characteristics of component from Pb/Cd contaminated loess in the washing process with Ethylene Diamine Tetraacetic Acid (EDTA) in reaction column, and the research objectives included base cations, loess nutrients, clay minerals and organic matter. The variation of clay minerals was analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), and 3D-EEM fluorescence spectrum was used for the identification of dissolved organic matter (DOM). The experimental results showed: the leaching component from loess is detected in the washing reaction. The final removal efficiency (240 min) of Pb and Cd from loess are 49. 86% and 62.25%, respectively. The sodium ions and nitrate nitrogen are the most easily leaching component, and little difference of clay minerals is identified before and after washing reaction. The fulvic acid-like (FA-like) material was firstly (10 min) detected around E(ex/em) = 240-250/320-340 and E(ex/em) = 260-290/450-470 in 3D-EEM fluorescence spectrum, and the humin acid-like (HA-like, E(ex/em) = 290-320/430-490) appeared at 60 min with weaker fluorescence intensity of FA-like (E(ex/em) = 240/320). The decreased fluorescence intensity of FA-like and HA-like, shown after 120 min and 240 min, indicated the component variation of DOM in the leaching solution. The spectroscopy approach is appropriate for characteristics identification of leaching component from co-contaminated loess.

[Application of Tessier-AAS to the non-biological transformation mechanism of chemical speciation of lead in red soil in agricultural area of central China].

The soil contamination of heavy metals, from the areas of mine, highway, industrial area, agricultural land and so on, is nowadays a serious issue all over the world. The contamination of heavy metals in large agricultural area might lead to the decrease of products quality and economic value. Actually, the accumulation amount of heavy metals by crops is much more related to the activated speciation, which is exchangeable and able to transform to the forms of carbonates, Fe-Mn oxides, organic matter and residual. Thus, the investigation to reveal the transformation mechanism of heavy metals caused by soil conditions might be appropriate to reduce the contaminated risk to crops. The vermicular red soil from the agricultural area of central China was used as sample in the paper, and the Tessier Sequential Extraction Procedure-atomic absorption spectroscopy (AAS) was applied to discuss the chemical speciation and non-biological transformation mechanism of Pb at different conditions. The results showed: the total amount of Pb is 32.56 mg x kg(-1), lower than the first level of the State Environmental Quality Standard for Soils. The Pb content of different speciation, with decreased concentration, is residual (54.55% of total Pb content), bound to Fe-Mn oxides, bound to organic matter, bound to carbonates and exchangeable. The pH value of red soil is related to the charge amount on surface of inorganic colloids and organic matter, and the water content of red soil would change the redox potential, effective for the variation of chemical speciation of Pb. The environmental factors of straw dosage and aging time could change Pb speciation, with Pb concentration of residual form the highest. The Muller index of Igeo is 0.3025, indicating the contribution of human activities. The Tessier Sequential Extraction Procedure-AAS is effective for the non-biological transformation mechanism identification of Pb speciation in red soil.

[Effect of pH on the Ultraviolet Spectra and Fluorescence Characteristics of Dissolved Organic Matter in the Process of Straw Humification].

Crop straw is the dominant by-product from agriculture and is regarded as the new source of non-point contamination. Straw incorporation is possible to solve the issues of straw reduction and reutilization, which is clearly required in the twelfth five-year-plan for national economic and social development of the People's Republic of China. At present, it is of noticeable lack of the investigation on straw incorporation behavior and detail humification product analysis in the representative regions under different environmental conditions. The ultraviolet and fluorescence spectrometry were used to reveal the characteristics of dissolved organic matter (DOM), affected by pH values, in the straw humification process in loess region. The results showed: the ultraviolet absorbance of DOM samples increased firstly and then decreased with the increasing wavelength from 200 to 700 nm, and the maximum absorbance peaks appeared around the wavelength of 240 nm. The maximum absorbance peaks (λmax) were greater at pH values of 6, 8 and 9 than that of 7, and the low degree of humification was indicated from the values of SUVA254, E3/E4 and A253/A203, caused by the short period of humification. The fluorescence peaks of extracted DOM from loess appeared around the regions of λ(dx/em) = 250/330 and λ(ex/em) = 325/450, referred as UV fulvic-like fluorescence, and visible fulvic-like and humic-like fluorescence, respectively. The increasing pH values resulted in the greater wavelength of absorbance peak, suggesting the increased aromaticity and conjugated degree, and the novel fluorescence peak was found in λ(ex/em) = 250/450. The pH values were more effective to change the UV fulvic-like fluorescence peaks intensity (increased firstly and then decreased) than that of visible fulvic-like and humic-like fluorescence, which might be related to buffer effect, fluorescence quenching (side effects) and component structure. The ultraviolet and fluorescence spectrometry were acceptable to illustrate the characteristics variation of DOM affected by pH values in the straw humification process.

[Effect of Temperatures and Lead Ions on 3D-EEMs of Dissolved Organic Matter (DOM) Derived from Straw Humification].

Straw incorporation is significant for straw reduction and reutilization, and is clearly required in the twelfth five-year-plan for national economic and social development of the People's Republic of China. The incorporated straw will naturally decompose and release the component of dissolved organic matter (DOM). At present, it lacks the research on straw humification behavior controlled by environmental factors and complexation effect between humification component and metal ions with fluorescence spectrometry in the representative region of loess. The fluorescence spectrometry was used to reveal the 3D-EEMs characteristics of DOM affected by temperatures and lead ions in the straw humification process, and the modified Stern-Volmer equation and Van't Hoff equation were applied to indicate the complexation parameters and thermodynamic constants between lead ions and DOM. The results showed: the humification temperatures affected little on fluorescence peaks of DOM and no peaks were obviously found to appear or disappear from the 3D-EEMs results. The fluorescence intensity decreased gradually at higher temperatures and in the presence of lead ions, the quenching effect might work in the process. The binding ability was more significant between lead ions and visible fulvic-like component shown from modified Stern-Volmer equation, and the values of ƒ revealed the complexation effect of lead ions and functional groups in DOM. Static quenching was the primary mechanism during the reaction process. The constants in Van't Hoff equation suggested the reaction was spontaneous and endothermic, and the disordered degree and the complexity were relatively low in the reaction system. The 3D-EEMs were acceptable to illustrate the variation of DOM characteristics under different temperatures and in the presence of lead ions in the straw humification process.

[Influence Mechanism of Dissolved Organic Matter (DOM) from Straw Humification on Chemical Speciation of Lead in Loess Region].

Heavy metal is regarded as one of the most representative contaminants in soil, and the chemical speciation is greatly related to the toxicity and transformation behavior, which attracts the attention of researchers for years. The environmental factors could change the speciation of heavy metals, plus to the complexity of soil system, and the transformation variation of speciation might occasional existed under similar conditions. At present, the different viewpoints of related issues are urgent to be investigated. The characteristics of DOM from straw humification were revealed with UV spectra, 3D-EEMs spectra and FTIR spectra, and the Tessier Sequential Extraction Procedure was used to study the speciation transformation behavior of lead affected by DOM. The linear relationship of the contents between DOC and lead bound to organic matter was indicated to further discuss the influence mechanism of lead speciation using FTIR. The results showed: the absorbance peak of DOM located in 229 nm in UV spectra, and the fluorescence peaks appeared around the regions of λ(ex)/em = 250/350 nm, λ(em) = 250/450 nm and λ(ex) = 330/450 nm, referred as UV fulvic-like fluorescence, and visible humic-like fluorescence, respectively. The dominant functional groups of DOM included--OH, C==O and N--H. The three fractions contents of lead (exchangeable, bound to iron and manganese oxides, residual) decreased, while that of lead bound to carbonates varied little. The contents of DOC and lead bound to organic matter appeared positive correlation (r == 0.691 8), indicating the effective complexation between DOM and lead ions. The functional groups of -OH, C==O and --COOH played an important role for the speciation transformation of lead, suggested from the FTIR spectra.

[Ex-situ remediation on co-contaminated arid loess in column with spectral methods].

The arid loess in northwestern China is one of the dominant soil types nationwide, the removal efficiency of Pb and chlorpyrifos in simulated co-contaminated loess was investigated by ethylene diamine tetra-acetic acid (EDTA) in ex-situ column experiment, and methods of ultraviolet spectroscopy (UV), atomic absorption spectroscopy (AAS), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR) were used to reveal the remediation characteristics and mechanism. The results showed that the flow rate and pH value of EDTA are responsible for the reaction curves. In the experimental conditions, the removal rates of Pb and chlorpyrifos are more than 70% and 90%, respectively, and the bioavailability of heavy metals decreases greatly. The SEM micrographs indicate the dense and rough surface of loess, and unclear surface and enhanced dispersion of particles appear after the reaction. The EDS results explain the phenomenon of Pb removal and elemental loss. The move, disappearance and decrease of wave peaks, shown from FTIR spectra, are the effect of various chemical environment in loess, and the reaction is more appropriate for physisorbed pollutants removal. The achievements are acceptable for co-contaminated loess remediation by EDTA in ex-situ column, showing potential for future application.

[Spectral characteristics of decomposition of incorporated straw in compound polluted arid loess].

The original loess from western China was used as soil sample, the spectral methods of scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), elemental analysis, Fourier transform infrared spectroscopy (FT-IR) and 13C nuclear magnetic resonance (13C NMR) were used to investigate the characteristics of decomposed straw and formed humic acids in compound polluted arid loess. The SEM micrographs show the variation from dense to decomposed surface, and finally to damaged structure, and the EDS data reveal the phenomenon of element transfer. The newly-formed humic acids are of low aromaticity, helpful for increasing the activity of organic matters in loess. The FTIR spectra in the whole process are similar, indicating the complexity of transformation dynamics of humic acids. The molecular structure of humic acids becomes simpler, shown from 13C NMR spectra. The spectral methods are useful for humic acids identification in loess region in straw incorporation process.

[Study on the co-adsorption mechanism of Pb (II) and chlorpyrifos on arid loess in northwestern China].

The co-adsorption characteristics of Pb(II) and chlorpyrifos on arid loess were investigated with batch adsorption procedures, and the co-adsorption mechanism was studied with approaches of SEM, FT-IR, XRD and theoretical analysis. The experimental results indicated that the adsorption process of Pb(II) and chlorpyrifos on loess fit better the Langmuir isotherm, the maximum adsorption capacity of q(m) is 12.5 and 0.64 mg x g(-1) for Pb(II) and chlorpyrifos on loess, respectively, and the reaction could be illustrated with pseudo-second order kinetic equation. The SEM micrograph of loess surface varies little after the adsorption process of Pb(II) and chlorpyrifos, and certain wave peaks of FTIR spectra red-shift, disappears or intensity-decrease, with the XRD pattern and theoretical analysis, the adsorption mechanism is described as follows: the adsorption of Pb (II) on arid loess is the chemical-effect of coordination-complexation and Van der Waals force; the physical-adsorption on chlorpyrifos involves the interception function, hydrogen bonds and Van der Waals force, and chemical adsorption effect to some extent. The organic matter in arid loess plays an important role in Pb(II) and chlorpyrifos adsorption.

[Effect of straw incorporation on three-dimensional fluorescence spectrum of dissolved organic matter in arid loess].

The three-dimensional fluorescence spectrum was used to investigate the fluorescence characterization of dissolved organic matter (DOM) before and after straw incorporation in arid loess, and the variation of humification degree and Pb(II) speciation were illustrated. The results showed that the fluorescence peaks of loess appears at the regions of lambda(ex/em) = 240-270/280-340 and lambda(ex/em) = 325/450, referred as UV fulvic-like fluorescence, and visible fulvic-like and humic-like fluorescence, respectively. After straw incorporation for 60 days, the intensity of UV fulvic-like fluorescence peaks increases, and novel humic-like fluorescence peaks appears around the region of lambda(ex/em) = 250/440 and lambda(ex/em) = 320-350/350-400. The longer time of straw incorporation would accelerate the humification degree of loess and decrease the bioactivity of Pb(II). The three-dimensional fluorescence spectrum is appropriate for characterization identification of DOM in arid loess before and after straw incorporation.

[Spectroscopic analysis of the crystallization mechanism of synthesized zeolite with XRD and FTIR approaches].

Zeolites were synthesized from fly ash using modified one-stage method. The changes in cation exchange capacity (CEC) and chemical elements of zeolite were investigated during the synthesis process to reveal the materials and elements transformation in solid-liquid system. The approaches of XRD, SEM and FTIR were used to indicate the crystallization characteristics and mechanism. The zeolite NaP1 was synthesized, and the CEC value reached to the maximum of 135 mmol/100g at 24 h. After the hydrothermal reaction for 12 h, the characteristic peak and metastable crystalline structure of zeolite NaP1 appeared, then the hydroxy sodalite products formed at 48 h. The crystallization process was the result of materials transformation: the elements of fly ash released into the liquid system for the melting effect of alkali solution, and the solid system played the role of skeleton in crystallization process, being the "source" and the "sink" of the reaction, respectively, and the achievements presented the crystallization mechanism of liquid-phase and solid-phase transformation.

FT-IR study on interactions between medroxyprogesterone acetate and solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems.

The intermolecular interactions between medroxyprogesterone acetate (MPA) and CHCl(3) and CCl(4) solvent in CHCl(3)/cyclo-C(6)H(12) and CCl(4)/cyclo-C(6)H(12) binary solvent systems have been studied by Fourier transform infrared spectroscopy (FT-IR). The experimental results showed that there are hydrogen bonding interactions between oxygen atoms of all carbonyl groups in MPA and hydrogen atom of CHCl(3) so as to form 1:3 complex of MPA with CHCl(3) and produce three new absorption bands at 1728.9-1736.1, 1712.7-1717.4 and 1661.9-1673.8 cm(-1), respectively. And, 1:1 complex of MPA with CCl(4) is formed in CCl(4)/cyclo-C(6)H(12) binary solvent as a result of hydrogen bonding interaction between C3 carbonyl group and empty d-orbital in chlorine atom of CCl(4) leading to producing new absorption band at 1673.2-1674.2 cm(-1). However, all free carbonyl and associated carbonyl stretching vibrations of MPA in CHCl(3)/cyclo-C(6)H(12) and CCl(4)/cyclo-C(6)H(12) binary solvent systems shift to lower wavenumbers with the increasing of volume fraction of CHCl(3) and CCl(4) in binary solvent systems owing to the dipole-dipole interaction and the dipole-induced dipole interaction between MPA and solvents.

[FTIR and XPS analysis of characteristics of synthesized zeolite and removal mechanisms for Cr(III)].

Zeolite products were synthesized from fly ash using one-stage method, and the characteristics of zeolite were analyzed with approaches of XRD, SEM and zeta potential, the removal mechanism for Cr(III) was further investigated by FTIR and XPS. From the pH value of 8 to 12, the negative zeta potential of NaP1 zeolite products decreased from -8.72 to -24.46 mV. The pseudo-second-order kinetics equation and Langmuir isotherm fit better the reaction, the maximum adsorption capacity was 33.557 0 mg x g(-1). Functional groups of -OH and Si-O were important for Cr(III) removal shown from FTIR spectra. The Cr(2p3/2) peak was found at the binding energy of 576.45 eV, indicating the effectiveness of reaction. The binding energy of Si-Si and Si-O increased by 0.25 eV and 0.60 eV, respectively, coordination effect might work between functional groups and Cr(III), and O(1s) binding energy decreased after the adsorption process. The removal for Cr(III) on zeolite was the comprehensive results of physical and chemical adsorption effects.