Sorption Behaviors of Organic Contaminants on Insolubilized Humic Acid

Hui Chen, College of Chemistry & Chemical Engineering, Northwest Normal University , Lanzhou , Gansu 730070, P.R. China, Email: lzchenh@sina.com
Mingguang Ma, Yiqing Yang, Yuan Zhang, Yingqin Wu, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou , Gansu 730070, P.R. China

Being widely presented in natural soils and waters, humic substances produced by the random condensation of breakdown products of terrestrial and aquatic plants as well as the extracellular metabolites of phytoplankton, are composed of the relatively diverse low molecular components forming dynamic associations stabilized by hydrophobic interactions and hydrogen bonds. Owing to the strong complexing ability with various heavy metal ions and partition effect with organic compounds, humic substances show the evident adsorption capacity on organic matters and heavy metals. In the remediation of contaminated soils, humic acids (HA) might not be used as an adsorbent because of their high solubility. The previous research indicated that insolubilized humic acid (IHA) had an excellent adsorptive ability, and was possibly used in the remediation technique. Our research focused on the characteristics of IHA by Fourier-transform infrared spectroscopy (FT-IR) and Electron micrograph scanning (S-450 SEM, Japan ). The surface structures of HA and IHA were compared by using nitrogen adsorption, while the specific surface, pore volume and pore distribution were determined with standard Brunauer-Emmett-Teller (BET) method. The images of SEM verified that the IHA particle size became smaller and the pore number increased after being treated by heating. Moreover, the cellulose was dispersed when the surfaces on the heated IHA got loose and rough. The results matched with that from nitrogen adsorption isotherms. The FT-IR spectra confirmed that infrared adsorb at a range of 500–4000 cm^-1 served as a direct classical means for the identification of the functional groups of organic compounds. In comparison with HA, the FT-IR spectra for IHA indicated that the peaks of C=O and O–H stretching vibration turned to decline near 1705cm^-1 and 3500cm^-1 ~ 3300cm^-1 respectively, which implied that the hydrophility of IHA decreased while its hydrophobicity increased.

The removal of p-nitrophenol from the aqueous solution was investigated by using IHA as an adsorbent，in which the effects of the temperature and time on the adsorption behaviors of p-nitrophenol were discussed as well. The themodynatic parameters proved that the p-nitrophenol adsorption on IHA was an endothermic and spontaneous process.

By using about 5L solution with the initial concentration of 50mg/L, the column tests were performed to determine the breakthrough curves of p-nitrophenol. The adsorption equilibrium could be gained within 150 minutes, however, the amount of dynamic saturation adsorption was greater than that of the thermal adsorption at the same pH and temperature. It also was found that a high and stable removal efficiency on IHA was obtained under the acidic conditions. The above research can be taken as a theoretical basis for the control and remediation of contaminated soils and waters.  

Keywords: insolubilized humic acids, heating treatment, characteristics, adsorption, p-nitrophenol

Risk Assessment and Remediation Criteria of Oil Leaking from Fluid-filled Underground Power Cables

Carlos A. Gotelli, Centro de Investigaciones Toxicológicas, Avenida Juan B. Alberdi 2986, C1406GSS Ciudad de Buenos Aires, Argentia, Tel: 54 11 4613 1100, Fax: 54 11 4613 3707
Mariano J. Gotelli, Centro de Investigaciones Toxicológicas, Avenida Juan B. Alberdi 2986, C1406GSS Ciudad de Buenos Aires, Argentia, Tel: 54 11 4613 1100, Fax: 54 11 4613 3707
Alfredo Lo Balbo, Centro de Investigaciones Toxicológicas, Avenida Juan B. Alberdi 2986, C1406GSS Ciudad de Buenos Aires, Argentia, Tel: 54 11 4613 1100, Fax: 54 11 4613 3707

Linear alkylbenzene (LAB) cable oils are used for the electrical insulation of high-voltage underground power cables.  At present, the electricity transmission system in the city of Buenos Aires consists in 400 Km of power lines running 2 meters deep. Due to thermal movement of the cables or third-party damage, leaks can occur, resulting in oil leaking into the surrounding environment.  The present literature indicates that relatively little is known about the fate of LAB as a bulk pollutant in soil.  A model of an underground cable was constructed to provide data on the conditions developed following a leak or damage, the dispersal properties of the fluid into the terrestrial subsoil and its potential ecological impact.  At a first instance, a simulation experiment was designed (soil in graduated flasks and oil columns) to study the permeability of the fluid and the migration rates.  It was observed that the vertical migration velocity in soil is 2.2 meters / year average, considering the physicochemical properties of the matrix assayed. In addition, risk assessment protocols were applied to evaluate the potential toxicity of LAB. Alkylbenzene has a low order of fish, mammalian and human toxicity and may be degraded naturally under aerobic conditions.  As a result, environmental damage resulting from accidentally fluid release is likely to be small.  Besides biodegradation, it was studied the chemical remediation as an alternative for immediate intervention and periodic monitoring.

Behaviour of Phenanthrene in Water-Polymerin-Alumina Three-Phase System

Marianna Iorio, Department of Soil, Plant, Envitonmental and Animal Production Sciences, University of Naples “Federico II”, Via Università 100, 80055 Portici (NA), Italy. Department of Plant, Soil and Insect Sciences, University of Massachusetts , Amherst , MA 01003 , Tel: 413-545-3862, Fax: 413-545-3958, Email: miorio@psis.umass.edu
Dr. Bo Pan, Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, Massachusetts 01003, Tel: 413-545-3862, Fax: 413-545-3958, Email: panbocai@gmail.com
Dr.  Renato Capasso, Department of Soil, Plant, Envitonmental and Animal Production Sciences, University of Naples “Federico II”, Via Università 100, 80055 Portici (NA), Italy , Tel: 0039-081-2539183, Fax: 0039-081-2539186, Email: capasso@unina.it
Dr. Baoshan Xing, Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, Massachusetts 01003, Tel: 413-545-5212, Fax: 413-545-3958, Email: bx@psis.umass.edu

Polymerin, the polymeric organic fraction from olive mill wastewaters, possesses humic acid-like properties and could represent a suitable biosorbent of potential economic interest. However, its interaction with phenanthrene is not known, especially in the presence of oxide particles. The aim of this study was to investigate the behaviour of phenanthrene in water in the presence of polymerin and in a polymerin-oxide-water system. Using a dialysis method, the interaction between polymerin and phenanthrene was studied as well as the interaction between phenanthrene and oxides (micro and nanoparticles). In addition, adsorption of polymerin on these oxides was examined and, during this experiment, the chemical properties of the polymerin left in solution after adsorption were analyzed by ultraviolet-visible spectroscopy and FTIR. Moreover, sorption of phenanthrene in a ternary system was evaluated at a fixed phenanthrene concentration with increasing polymerin concentration on both micro and nanoparticles. The results showed that phenanthrene sorption is linear for both micro and nanoparticles with the sorption of microparticles being one order of magnitude lower than the nanoparticles. Sorption by polymerin is nonlinear, and its sorption capacity is two orders of magnitude higher than that of nanoparticles. Sorption of polymerin on the two types of particles follows a Langmuir type, with a Sm of 204000 and 2970 mgOC/kg for nano and microparticles, respectively. Chemical property analysis showed that the nanoparticles are able to adsorb polymerin indistinctly, but the microparticles caused fractionation, adsorbing preferentially the aromatic fraction. Sorption studies in a ternary system demonstrated that the amount of phenanthrene sorbed on particles is related with the amount of organic carbon complexed, until a saturation point beyond which polymerin predominates the phenanthrene sorption on the Al-polymerin complex.

Dendrochemical Application to Evaluate the Absorption of Diesel and Hydrocarbon Contaminants in Tree Rings for Recent Contamination Event

Patricia Duplessis, Sciences de l’Environnement, Université du Québec à Trois-Rivières, C.P. 500, Trois-Rivières, QC, Canada, G7A 5H7, Tel: 819-376-5011, Fax: 819-376-5210
Diane Saint-Laurent, Département de géographie, Université du Québec à Trois-Rivières, C.P. 500, Trois-Rivières, QC, Canada, G7A  5H7, Tel: 819-376-5011, Fax: 819-376-5210
Joëlle Marion, INRS-ETE, Laboratoire de Dendrogéochimie, 490, Rue de la Couronne, QC, Canada, G1K 9A9, Tel: 418-654-2524, Fax: 418-654-2600

In June 2006, CN freight cars derailed near Charette, a municipality located on the north shore of the St. Lawrence River about 140 kilometres northeast of Montréal. According to CN officials, two tank cars containing gasoline, oil and diesel derailed, one spilling an undetermined quantity of oil, with three others dripping oil. Some of the derailed cars leaked petroleum substances into the Wolf River . One of the cars reportedly emptied the 200,000 litres of gasoline or diesel fuel it was carrying. Federal and provincial environment officials and workers have created a dam on the river to contain the spill. All of the spillage is on the east side of the tracks, with a body of water on the western side of the tracks not at risk of being impacted. The train accident contaminated the surface soil and probably the grounwater. The contamination event appears to be an opportunity for researchers who use dendrochemical analysis to measure the absorption rate of hydrocarbon contaminants in tree rings. The first objective of this study is to determine the response of trees located near the contamination site and use dendrochronological and dendrochemical methods. Field work began in November 2006, five months after the contamination event, and will continue over the next years (2006-2009). Red ash (Fraxinus pennsylvanica Marsh.) was used for the dendrochemical analyses. This species is the same as the trees that were used for the study on the Saint-François and Massawippi rivers, and all the results will be used for a comparative analysis. At present, the results obtained for the soil surface samples (0-5 cm depth) surrounding the contamination site show very high levels of contaminants (BTEX) ranging from 4,900 to 21,000 mg/kg (ppm), and the initial results of the dendrochemical analyses also indicate high concentrations of contaminants on the tree rings.
 

NAPL Contamination in Freezing Ground

Student Presenter

Kamaljit Singh, School of Aerospace, Civil and Mechanical Engineering, The University of New South Wales @ Australian Defence Force Academy, Northcott Drive, Canberra, ACT, 2600, Australia, Tel: +61 2 6268 8357, Fax: +61 2 6268 8337, E-mail: k.singh@adfa.edu.au
Robert K. Niven, School of Aerospace, Civil and Mechanical Engineering, The University of New South Wales @ Australian Defence Force Academy, Northcott Drive, Canberra, ACT, 2600, Australia, Tel: +61 2 6268 8330, Fax: +61 2 6268 8337

The behavior and movement of non-aqueous phase liquid (NAPL) contaminated spills in cold regions are not well understood at microscopic levels. A two-dimensional cell, consisting of a monolayer of 0.5mm glass beads held between two glass sheets, was constructed to visualize the effect of various freeze-thaw cycles (in the range of +4.0 to -2.5oC) on the pore-scale movement of residual light NAPL (LNAPL) ganglia. The cell was photographed at the end of each freeze-thaw cycle in two separate set of experiments. Result of the first set of experiments showed a significant change in spatial distribution of ganglia due to ice crystal formation, where ganglia were found to be moved both in vertical and horizontal directions into the unfrozen zone ahead of freezing front depending on the interfacial forces between water and LNAPL, and also the pressure induced by frozen part, even at higher cooling rates (27.5oC/hr) which are greater than threshold values for solute rejection mentioned in literature. From the second set of experiments, in which samples were photographed during the freezing and thawing processes, it was observed that once separated from main mass and then trapped into polycrystalline ice during freezing, LNAPL ganglia can be ruptured into smaller portions during thawing, giving rise to number of singlets and subsinglets in the medium. The experiments have significant implications for the management and remediation of LNAPL in cold regions.

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