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Equilibrium and Kinetic Characteristic of Adsorption of Cu2+, Pb 2+ on a Novel Anionic Starch Microspheres Full text
2011
Yang, YaTi | Wei, XiuZhi | Wan, JuanMin | Meng, ZhaoFu
Neutral starch microspheres (NSMs) were synthesized with epichlorohydrin as the cross-linking agent from soluble starch by inverse microemulsion method. Anionic starch microspheres (ASMs) were prepared from NSMs by the secondary polymerization with chloroacetic acid as the anionic etherifying agent. Scanning electron microscopy (SEM) revealed that microspheres had good sphericity and fine dispersibility, and the average particle size was about 75 μm. The adsorption procedure of Cu2+, Pb2+ on ASMs was carried out by batch experiments, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms, the adsorption equilibrium data were found to fit the Langmuir and Freundlich isotherm model, the Freundlich isotherm was more adequate than the Langmuir isotherm in simulating the adsorption isotherm of Cu2+,the adsorption of Cu2+, Pb2+ on ASMs was a spontaneous, the isosteric heat of adsorption at different adsorption levels was always negative and indicative of an exothermic process. The pseudo first- and second-order kinetic models were used to describe the kinetic data, and the rate constants were evaluated. The experimental data fitted well to the second-order kinetic model, which indicated that the chemical sorption was the rate-limiting step, instead of mass transfer.
Show more [+] Less [-]Mineralisation of Surfactants Using Ultrasound and the Advanced Fenton Process Full text
2011
Naldoni, Alberto | Schiboula, Alessandro | Bianchi, Claudia L. | Bremner, David H.
The destruction of the surfactants, sodium dodecylbenzene sulfonate (DBS) and dodecyl pyridinium chloride (DPC), using an advanced oxidation process is described. The use of zero valent iron (ZVI) and hydrogen peroxide at pH = 2.5 (the advanced Fenton process), with and without, the application of 20 kHz ultrasound leads to extensive mineralisation of both materials as determined by total organic carbon (TOC) measurements. For DBS, merely stirring with ZVI and H2O2 at 20°C leads to a 51% decrease in TOC, but using 20 kHz ultrasound at 40°C, maintaining the pH at 2.5 throughout and adding extra amounts of ZVI and H2O2 during the degradation, then the extent of mineralisation of DBS is substantially increased to 93%. A similar result is seen for DPC where virtually no degradation occurs at 20°C, but if extra amounts of both ZVI and hydrogen peroxide are introduced during the reaction at 40°C and the pH is maintained at 2.5, then an 87% mineralisation of DPC is obtained. The slow latent remediation of both surfactants and the mechanism of degradation are also discussed.
Show more [+] Less [-]Lime Residues and Metal Sequestration in Sediments of Excessively Limed Lakes Full text
2011
Wällstedt, Teresia
Sediment profiles from ten excessively limed lakes were used to study the occurrence of lime residues as a result of incomplete lime dissolution and the influence of treatment with very high lime doses on the sequestration of metals in lake sediments. The sediment profiles were subjected to multi-element analysis and compared to sediment profiles from previous studies of lakes limed with normal lime doses and untreated reference lakes. The high lime doses were found to result in large lime residues in the sediment, with lime concentrations of up to 70% of the dry sediment in the studied lakes. Excessive liming, like liming with normal doses, was found to cause increased sequestration in sediments of, e.g. Cd, Co, Ni and Zn, metals where the mobility is known to be highly pH dependent, compared to non-limed reference lakes. No effect of liming on the sequestration of Cu, Cr, Pb and V could be shown. The size of the lime dose did not seem to influence the metal sequestration in the sediment, since no difference between the excessively limed lakes and lakes limed with normal doses was found. On the contrary, the large lime residues were found to cause a dilution of the metal concentrations in the sediments, since lime products used for lake liming generally have lower metal concentrations compared to the sediments.
Show more [+] Less [-]Effects of Soil Amendments on Growth and Metal Uptake by Ocimum gratissimum Grown in Cd/Zn-Contaminated Soil Full text
2011
Chaiyarat, Rattanawat | Suebsima, Rujira | Putwattana, Narupot | Kruatrachue, Maleeya | Pokethitiyook, Prayad
Hydroponic and pot experiments were conducted to assess the uptake of heavy metals (Cd and Zn) by a common crop plant, African basil, Ocimum gratissimum. In addition, the effects of soil amendments, hydroxyapatite (HA) and cow manure on plant growth and metal accumulations were compared. In the hydroponic study, plants were exposed to various concentrations of Cd (2.5 and 5 mg L⁻¹) and Zn (10 and 20 mg L⁻¹) for 15 days. O. gratissimum was shown to be a Cd accumulator more than a Zn accumulator. Cadmium concentration in its shoots exceeded 100 mg kg⁻¹. In the pot experiments, soils from a heavily Cd-contaminated site (Cd 67.9 mg kg⁻¹ and Zn 2,886.8 mg kg⁻¹) were treated with cow manure and HA at the rates of 10% and 20% (w/w), and 0.75 and 1.5% (w/w), respectively. Plants were grown in the greenhouse for 3 months. The addition of cow manure resulted in the highest biomass production and the lowest accumulations of Cd in plant parts, while HA was more efficient than cow manure in reducing Zn uptake. Leaves of African basil showed a decreased Cd concentration from 1.5 to 0.3 mg kg⁻¹ (cow manure) and decreased Zn concentration from 69.3 to 34 mg kg⁻¹ (HA). This clearly demonstrates the efficiency of HA and cow manure in reducing metal content in leaves of plants grown on high metal-contaminated soil to acceptable or close to acceptable values (0.2 mg kg⁻¹ for Cd, 99.4 mg kg⁻¹ for Zn).
Show more [+] Less [-]Selective recovery of chromium, copper, nickel, and zinc from an acid solution using an environmentally friendly process Full text
2011
Machado, Manuela D. | Soares, Eduardo V. | Soares, Helena M. V. M.
PURPOSE: Real electroplating effluents contain multiple metals. An important point related with the feasibility of the bioremediation process is linked with the strategy to recover selectively metals. In this work, a multimetal solution, obtained after microwave acid digestion of the ashes resulted from the incineration of Saccharomyces cerevisiae contaminated biomass, was used to recover selectively chromium, copper, nickel, and zinc. RESULTS: The acid solution contained 3.8, 0.4, 2.8, and 0.2 g/L of chromium(III), copper, nickel, and zinc, respectively. The strategy developed consisted of recovering copper (97.6%), as a metal, by electrolyzing the solution at a controlled potential. Then, the simultaneous alkalinization of the solution (pH 14), addition of H2O2, and heating of the solution led to a complete oxidation of chromium and nickel recovery (87.9% as a precipitate of nickel hydroxide). After adjusting the pH of the remaining solution at pH 10, selective recovery of zinc (82.7% as zinc hydroxide) and chromium (95.4% as a solution of cromate) was achieved. CONCLUSION: The approach, used in the present work, allowed a selective and efficient recovery of chromium, copper, nickel, and zinc from an acid solution using a combined electrochemical and chemical process. The strategy proposed can be used for the selective recovery of metals present in an acid digestion solution, which resulted from the incineration of ashes of biomass used in the treatment of heavy metals rich industrial effluents.
Show more [+] Less [-]Sediment contact test with Potamopyrgus antipodarum in effect-directed analyses—challenges and opportunities Full text
2011
Schmitt, Claudia | Vogt, Christian | Machala, Miroslav | de Deckere, Eric
BACKGROUND AND SCOPE: Effect-directed analysis is increasingly used for the identification of key toxicants in environmental samples and there is a growing need for in vivo biotests as diagnostic tools. Within this study, we performed an in vivo sediment contact test, applicable on both native field samples and their extracts or fractions, in order to be able to compare the results from both field and laboratory studies. MATERIAL AND METHODS: A sediment contact test with the prosobranch snail, Potamopyrgus antipodarum, was carried out on extracts and fractions of field sediments from three European river basins. The results were compared with previous results of the native field samples. RESULTS: In contrast to the native sediments, the extracts of the samples led to an overall decrease in reproduction. Even the chosen reference sites had an adverse effect on the snails' reproduction. It appeared that a higher bioavailability in the organic extracts, together with a changing composition of compounds could have lead to this change in effects. The fractionation of the extracts partly led to a more differentiated picture, but the resolution was not high enough to see any distinct effects on the snails' reproduction. DISCUSSION AND CONCLUSION: Our results highlight the importance of the use of in vivo biotests and point out the relevance of bioavailability in native sediments. For further fractionation studies, a more realistic extraction procedure, together with a higher resolution fractionation, would be appropriate in order to separate individual bioavailable compounds more efficient.
Show more [+] Less [-]Do metal concentrations in moss from the Zackenberg area, Northeast Greenland, provide a baseline for monitoring? Full text
2011
Zechmeister, Harald G. | Dullinger, Stefan | Koellensperger, Gunda | Ertl, Siegrun | Lettner, Christian | Reiter, Karl
PURPOSE: This study aims at evaluating (a) whether concentrations of a suite of elements in mosses sampled in the arctic region around Zackenberg reflect background concentrations useful for estimating pollution levels in industrialized parts of the northern hemisphere as is attempted, e.g. in the framework of the UNECE ICP Vegetation monitoring programme, and (b) whether there are any influences from Zackenberg research station detectable in these concentrations. METHODS: Two moss species were sampled according to guidelines used in the UNECE ICP Vegetation programme. Samples were analysed for ¹⁹⁵Pt at low resolution, ²⁷Al, ⁵²Cr, ⁶⁵Cu, ⁶⁶Zn, ⁹⁵Mo, ¹¹¹Cd, ¹¹⁸Sn, ¹²¹Sb and ²⁰⁸Pb at medium resolution and ⁷⁵As at high resolution on an Element 2 inductively coupled plasma sector field mass spectrometer. RESULTS: Except for Al, As and Cr, data from Zackenberg showed significantly lower mean element concentrations than those reported in comparable studies from all over the world including those from other Arctic environments. Minimum concentrations in Zackenberg mosses were consistently below all values reported so far for all elements analysed. The results of a PCA suggested only a slight impact from Zackenberg research station on concentrations of Cd, Mo and Zn in moss. CONCLUSIONS: We conclude that the sites in Zackenberg can be considered true background sites providing baseline concentrations of at least eight elements for comparable monitoring studies.
Show more [+] Less [-]Biomonitoring of chemical elements in an urban environment using arboreal and bush plant species Full text
2011
Rucandio, Maria Isabel | Petit-Domínguez, Maria Dolores | Fidalgo Hijano, Concepción | García-Giménez, Rosario
PURPOSE: The aim of this work was to investigate the possibility of using several bush and arboreal plant species, usually present as ornamental plants in street and parks, as environmental indicators of pollution. This is a research paper that evaluates the real possibility of using a fast and low-cost procedure to evaluate the pollution degree through data obtained from plant species growing within an urban environment. METHODS: Leaves of six different bush and arboreal species were collected from different parts of Madrid (Spain), ranging from highly polluted considered areas to medium and low contaminated ones. A total of 66 chemical elements, from major to minor and trace, were determined for every leaf sample by inductively coupled plasma-mass spectrometry. Statistical analyses were carried out using mainly box and whisker plots, linear discriminant analysis and cluster analysis. RESULTS: The pollution by different elements of the studied areas of Madrid cannot be considered generally dangerous for human health. The level detected for the contaminants, in general, is similar or lower than other urban cities. Pb and V concentrations in plant samples tend to increase as traffic density increases. The different studied plant species showed a different capability of accumulation of certain elements. Cedrus deodara accumulates specially Ag, Hg, Mo and V; Cupressus sempervirens, Zr; Pinus pinea, As and Sb; Nerium oleander Ni, Pb, Mo and Se; Ligustrum ovalifolium, Sc and V; and Pittosporum tobira, Ag, Cd, Rb and Sc. CONCLUSIONS: The leaves and needles collected from bush and arboreal plants common in this city have demonstrated to be useful to evaluate the level of pollution not only through the chemical analysis but also through the recognition of the visual injury symptoms. The application of multivariate statistical techniques combined with determining of element concentration and correlation analysis has been proved to be an effective tool for reach the objectives of the present work. This allows visualising quickly the damages and leading the sampling through the points of high-level pollution, saving analysis, time and money.
Show more [+] Less [-]Sustainable development of deep-water seaport: the case of Lithuania Full text
2011
Burskyte, Vilma | Belous, Olga | Stasiškienė, Žaneta
Introduction In 2003, the Japan International Cooperation Agency carried out a development feasibility study of Klaipeda Seaport (Lithuania). The focus in this study was the evaluation of environmental impacts of the port expansion because it is located in an ecologically sensitive area. While the Japanese researchers focused on the environmental impact analysis, they did not provide unambiguous conclusions. The problems remained unresolved and required further, more detailed consideration and deeper analysis. Purpose Environmental sustainability in seaports is an issue of timely importance in many countries given the rapid increase in port-to-port traffic and harbor capacity. This paper explores the situation in Klaipeda Seaport (Lithuania) which is the northernmost ice-free port on the Eastern coast of the Baltic Sea and its challenges in terms of environmental aspects and current pollution situation. This port plays an important role in the economic development of the region and in creating a sustainable society, i.e., a society that continues to develop economically without increasing its impact on our living environment and where the possible reduction of its current impact can be huge due to the fact that the seaport is a place where transport and logistics intersect and constitute large-scale industrial estates. Increasingly, they also turn towards sustainability. Methods Society faces the need for radical change because of increasing technological progress and increasing environmental impact. Environmental and public issues must be addressed by a systemic approach to find harmony among all the subsystems. Therefore, the authors of the article performed an assessment of the deep-water port of Klaipeda sustainable development opportunities tackling the following tasks: (1) Assessing Klaipeda port and the projected deep-water port of the current environment state; (2) Assessing the impact of the water quality of Klaipeda port, depending on the intensity of activity; (3) Assessing the projected impact of the deep-water port on the environment. Results and conclusions The results of the performed research allowed: (a) to reveal strengths and weaknesses of Klaipeda port development and the potential conflicts of interest among different stakeholders, (b) to identify the set of problem solutions seeking sustainable Klaipeda port development; (c) to develop the set of sustainability indicators to monitor the efficiency of the development.
Show more [+] Less [-]Evaluating threats to an endangered species by proxy: air pollution as threat to the blue swallow (Hirundo atrocaerulea) in South Africa Full text
2011
Kylin, Henrik | Bouwman, Henk | Evans, Steven W
Background, aim, and scope The blue swallow (Hirundo atrocaerulea) is one of the most threatened bird species in southern Africa. Among terrestrial birds, its plumage is known to be the most water repellent, an adaptation to foraging on the wing in dense fog. Despite this unique adaptation, the nesting success of the blue swallow at the Blue Swallow Natural Heritage Site (BSNHS) is lower during years with high incidence of fog. As the phenomenon is not observed at other nesting sites, we hypothesized that this is due to changes in the air chemistry at the BSNHS. In the immediate proximity of the BSNHS, plantations of exotic trees (e.g., pines and eucalypts), rich in volatile organic compounds (VOCs), are dominant features. In addition, air pollution from the Johannesburg area is transported with the surface winds and mix with VOCs released from exotic trees. Together with the high humidity and high elevation, these conditions may result in the formation of sulphonates. Sulphonates are strong detergents, and the presence of these in the fog could lead to decreased water repellence of the plumage. This study was performed in order to determine the occurrence and distribution of sulphonates in the BSNHS and to compare these with sulphonates formed in other locations in South Africa. Because the blue swallow is endangered, pine needles were used as proxy to detect formation of sulphonates. Methods We sampled pine needles with different exposure to air pollutants, in climates with different humidity, and at different elevation and analyzed these for sulphonates using mass spectrometry. Results Pine needles from high elevations and the BSNHS, with high humidity, and exposure to air pollution contained significantly higher concentrations of sulphonates than pine needles from low elevations or from high elevations with a dryer climate or a different combination of air pollutants. Conclusions These findings lead to two conclusions. First, the occurrence and distribution of sulphonates may be explained by chemical reactions between sulphur dioxide and organic compounds in the humid air induced by ultraviolet radiation. Second, elevated concentrations of sulphonates in the fog could affect the water repellence of the blue swallow plumage, possibly decreasing their capacity to forage in the fog. We cannot prove conclusively that this is the reason why the number of blue swallows at the BSNHS has decreased dramatically, but for endangered species, we may have to rely on proxies to draw conclusions about outside threats. All such information should be valuable in devising protection plans for species under threat. Recommendations and perspectives The use of proxies to elucidate threats to endangered species should be evaluated in a broad scale. The mist-belt habitat in general is threatened by many human activities. These findings indicate that air pollution and the proximity of volatile organic compound (VOC) sources close to mist-belt habitat refuges may be an unrecognised conservation threat to the animals inhabiting them.
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