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Novel insights in Al-MCM-41 precursor as adsorbent for regulated haloacetic acids and nitrate from water Full text
2012
Bruzzoniti, Maria Concetta | De Carlo, Rosa Maria | Sarzanini, Corrado | Caldarola, Dario | Onida, Barbara
High concentration of NO 3 − in groundwater has raised concern over possible contamination of drinking water supplies. In addition, the formation of haloacetic acids (HAAs) as by-products during disinfection with chlorine-based agents is still a relevant issue, since HAAs pose serious health hazard. In this work, we investigated the affinity of a precursor of Al-MCM-41 (a mesostructured hexagonal aluminosilicate containing the template surfactant) towards nitrate and HAAs, for its possible application in the removal of these pollutants from natural and drinking waters. Additionally, adsorption kinetics and isotherms were studied. The adsorbent was synthesized using cetyltrimethylammonium bromide as surfactant and characterized by physico–chemical techniques. Simulated drinking water was spiked with the EPA-regulated HAAs (monochloroacetic (MCAA), monobromoacetic (MBAA), dichloroacetic (DCAA), dibromoacetic (DBAA), and trichloroacetic (TCAA) acids) and placed in contact with the adsorbent. The effect of matrix composition was studied. Adsorption kinetic studies were performed testing three kinetics models. For the adsorption studies, three adsorption isotherm approaches have been tested to experimental data. The pollutant recoveries were evaluated by suppressed ion chromatography. The affinity of the adsorbent was TCAA = DBAA = DCAA > MBAA > MCAA with DCAA, DBAA, and TCAA completely removed. A removal as high as 77 % was achieved for 13 mg/L nitrate. The adsorption isotherms of NO 3 − and monochloroacetic acid can be modeled by the Freundlich equation, while their adsorption kinetics follow a pseudo-second-order rate mechanism. The adsorbent exhibited high affinity towards HAAs in simulated drinking water even at relevant matrix concentrations, suggesting its potential application for water remediation technologies.
Show more [+] Less [-]Acute toxicity of polybrominated diphenyl ethers (PBDEs) for turbot (Psetta maxima) early life stages (ELS) Full text
2012
Mhadhbi, Lazhar | Fumega, José | Boumaiza, Moncef | Beiras, Ricardo
BACKGROUND, AIM AND SCOPE: The environmental presence of polybrominated diphenyl ethers (PBDEs), among which BDE-47 and BDE-99 are particularly abundant, makes toxicity data necessary to assess the hazard risk posed by PBDE to aquatic organisms. This study examines the effects of BDE-47 and BDE-99 on embryo-larval stages of the marine flatfish turbot. MATERIALS AND METHODS: The turbot embryos were exposed at nominal concentrations of BDE-47 and BDE-99 for 6 days. Selected dose levels were relevant for investigating sublethal and lethal effects. RESULTS: Both tested compounds caused lethal toxicity as well as non-lethal malformations during embryo development. We found a high toxic potency of BDE-47 compared to BDE-99 (LC50 values for embryos and larvae, respectively, BDE-47: 27.35 and 14.13 μg L−1; BDE-99: 38.28 and 29.64 μg L−1). DISCUSSION: The present study shows high sensitivity of fish early life stages (ELS) to PBDE compounds. Based on environmental concentrations of dissolved PBDEs from various aquatic ecosystems, waterborne BDE-47 and BDE-99 pose little risk of acute toxicity to marine fish at relevant environmental concentrations. CONCLUSIONS: Turbot fish ELS proved to be an excellent model for the study of ecotoxicity of contaminants in seawater. The results demonstrate harmful effects of PBDE on turbot ELS at concentrations in the range of parts per billion units. RECOMMENDATIONS AND PERSPECTIVES: In the perspective of risk assessment, ELS endpoints provide rapid, cost-effective and ecologically relevant information, and links should be sought between these short-term tests and effects of long-term exposures in more realistic scenarios.
Show more [+] Less [-]Metal contamination of soils and plants associated with the glass industry in North Central India: prospects of phytoremediation Full text
2012
Varun, Mayank | D’Souza, Rohan | Pratas, João | Paul, Manoj S.
INTRODUCTION: The effect of the glass industry on urban soil metal characterization was assessed in the area of Firozabad, India. A comprehensive profile of metal contamination was obtained in five zones each containing five specific sites. FINDINGS: Zn, Cd, and As showed a greater accumulation, whereas accumulation of Ni and Cu was high in limited samples. Positive correlation was found for the metal pairs Cu-Zn, Cu-Co, and Cu-Cr at P < 0.01. Moderate positive correlation was also observed between Zn-Co, Mn-Cd, Mn-As, Pb-As, and Ni-Cu at P < 0.05. Integrated contamination indices indicate that 60% of the sites were heavily contaminated while 28% were moderately contaminated. Phytoremedial potential of native flora (twenty herbs, three shrubs, and two grasses) was also assessed by analyzing their metal uptake. Individual elements displayed remarkably different patterns of accumulation in soils as well as in plants. Mn, Zn, Cu, and As were predominantly partitioned in shoots, Co and Cd in roots while Pb, Cr, and Ni almost equally between shoots and roots. Most plants exhibited capabilities in mobilizing Co, Pb, Cr, and Ni in the root zone. CONCLUSION: Potential phytoextractors include Datura stramonium and Chenopodium murale while phytostabilizers include Calotropis procera and Gnaphalium luteo-album. Poa annua showed potential in both categories. None of the species showed phytoremedial potential for Co and Ni.
Show more [+] Less [-]Identification and evaluation of air-pollution-tolerant plants around lignite-based thermal power station for greenbelt development Full text
2012
Govindaraju, M. | Ganeshkumar, R. S. | Muthukumaran, V. R. | Visvanathan, P.
INTRODUCTION: Thermal power plants emit various gaseous and particulate pollutants into the atmosphere. It is well known that trees help to reduce air pollution. Development of a greenbelt with suitable plant species around the source of emission will mitigate the air pollution. Selection of suitable plant species for a greenbelt is very important. MATERIALS AND METHODS: Present study evaluates different plant species around Neyveli thermal power plant by calculating the Air Pollution Tolerance Index (APTI) which is based on their significant biochemical parameters. Also Anticipated Performance Index (API) was calculated for these plant species by combining APTI values with other socio-economic and biological parameters. DISCUSSION: Based on these indices, the most appropriate plant species were identified for the development of a greenbelt around the thermal power plant to mitigate air pollution. Among the 30 different plant species evaluated, Mangifere indica L. was identified as keystone species which is coming under the excellent category. CONCLUSION: Ambient air quality parameters were correlated with the biochemical characteristics of plant leaves and significant changes were observed in the plants biochemical characteristics due to the air pollution stress.
Show more [+] Less [-]Biosorption of strontium from aqueous solution by fungus Aspergillus terreus Full text
2012
Khani, M. H. | Pahlavanzadeh, H. | Alizadeh, K.
INTRODUCTION: The biosorption characteristics of strontium ions using fungus Aspergillus terreus were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, initial metal concentration, and temperature were studied. MATHEMATICAL DESCRIPTION: Fungus A. terreus exhibited the highest strontium uptake capacity at 15°C at an initial strontium ion concentration of 876 mg L−1 and an initial pH of 9. Biosorption capacity increased from 219 to 308 mg g−1 with a decrease in temperature from 45°C to 15°C at this initial strontium concentration. The equilibrium data fitted very well to the Langmuir adsorption model in the concentration range of strontium ions and at all the temperatures studied. CONCLUSION: Evaluation of the experimental data in terms of biosorption dynamics showed that the biosorption of strontium onto fungus followed the pseudo-second-order dynamics well (R2 > 0.985). The calculated thermodynamics parameters (−1.64 < ∆G° < −1.93 kJ mol−1 at temperatures of 45–15°C, ∆H° = −4.83 kJ mol−1 and ∆S° = −0.01 kJ mol−1 K−1) showed that the biosorption of strontium ions were feasible, spontaneous, and exothermic at the temperature ranges of 15–45°C.
Show more [+] Less [-]Genotoxicity potential of a new natural formicide Full text
2012
Cotelle, Sylvie | Testolin, Renan C. | Foltête, Anne-Sophie | Bossardi-Rissardi, Georgiana | Silveira, Rosilene A. | Radetski, Claudemir M.
BACKGROUND, AIM, AND SCOPE: Assessment of environmental impacts from pesticide utilization should include genotoxicity studies, where the possible effects of mutagenic/genotoxic substances on individuals are assessed. In this study, the genotoxicity profile of the new formicide Macex® was evaluated with two genotoxicity tests, namely, the micronucleus test with mouse bone marrow and Vicia faba, and a mutagenicity test using the Ames Salmonella assay. MATERIALS AND METHODS: The bacterial reverse mutation test (Salmonella typhimurium strains TA97, TA98, TA100, TA102, and TA1535), the Vicia root tip and mouse micronucleus tests were conducted according to published protocols. RESULTS: In the range of the formicide Macex® concentrations tested from 0.06 to 1.0 g L−1 (or mgkg−1 in the mouse test), no genotoxicity was observed in the prokaryotic or eukaryotic test organisms. However, at Macex® concentrations of 0.5 g L−1 and above a significant decrease in the mitotic index (P ≤ 0.05) in the V. faba was observed. Micronucleus formation was likewise increased in the test organism at concentrations starting at 2.0 g L−1. CONCLUSIONS: These data allow us to classify this natural formicide preparation as a product with no geno-environmental-impact when applied at recommended concentrations.
Show more [+] Less [-]Zeolitic bagasse fly ash as a low-cost sorbent for the sequestration of p-nitrophenol: equilibrium, kinetics, and column studies Full text
2012
Shah, Bhavna | Tailor, Ritesh | Shah, Ajay
PURPOSE: The purpose of the research is to investigate the application of bagasse fly ash, a sugar industry solid waste for the synthesis of zeolites and their behavior for the sorption of p-nitrophenol (p-NP). METHODS: Zeolitic materials were prepared from bagasse fly ash using alkaline hydrothermal (CZBFA) and fusion (FZBFA) treatment. Comparative batch sorption studies of prepared zeolitic material and virgin material were undertaken to determine their capacities for removal of p-nitrophenol. RESULTS: PXRD patterns revealed that zeolite P and analcime were the dominant contents of synthesized zeolitic material. Chemical composition, morphology, and crystalline nature of CZBFA and FZBFA were characterized by XRF, FTIR, and SEM. The Langmuir, Freundlich, Dubinin Redushkwich, and Temkin sorption isotherms were applied to compare the sorption nature and capacity of synthesized CZBFA and FZBFA with virgin BFA. For each sorbent-p-NP system, a pseudo-second-order kinetic model described the sorption kinetics accurately. The thermodynamics of the p-NP-sorbent systems exhibit an exothermic sorption process. Intraparticle diffusion model shows that the sorption rate was controlled by film diffusion followed by pore diffusion. Regeneration of sorbents was carried out by desorption studies with HCl, NaOH, and SDS detergent. The column studies were performed for the practical utility of sorbents, and breakthrough curve were obtained, which exhibit higher sorption capacity than batch method. CONCLUSION: The sorption capacities of the synthesized zeolites had improved sorption capacities for the sequestration of p-NP and can be utilized as low-cost sorbents for treatment of p-nitrophenolic wastewater.
Show more [+] Less [-]Airborne lead levels in the Korean peninsula: characterization of temporal and spatial patterns and cancer risk analysis Full text
2012
Mutlu, Atilla | Lee, Byeong-Kyu
INTRODUCTION: This study collected long-term airborne lead concentrations in the Korean peninsula and analyzed their temporal, spatial, and cancer risk characterization. METHODS: Approximately, 12,000 airborne samples of total suspended particulate (TSP) were collected from 30 ambient air monitoring stations in inland (Daegu, Daejeon, Gwangju, and Seoul) cities and portal cities (Incheon, Busan, and Ulsan) over a period of 7 years (2004–2010). High volume air samplers were employed to collect daily TSP samples during the second week of the consecutive months throughout the entire study period. The concentrations of Pb extracted from the TSP samples were analyzed using either inductively coupled plasma-atomic emission or flame atomic absorption spectrometry. RESULTS: The long-term high mean Pb concentrations were observed in the port cities including Incheon (88 ± 18 ng/m3), Ulsan (61 ± 7 ng/m3), and Busan (58 ± 6 ng/m3). In the temporal analysis, seasonal mean Pb levels were relatively higher in winter and spring than those in summer and fall. In the spatial analysis, the mean Pb levels in spring, winter, and fall from Incheon, which showed the highest seasonal concentrations except summer, were 110 ± 19, 101 ± 18, and 76 ± 23 ng/m3, respectively. In summer, the highest seasonal mean Pb level was observed in the largest industrial city and the second port city, Ulsan (78 ± 15 ng/m3), followed by Incheon (65 ± 13 ng/m3). CONCLUSION: The estimated excess cancer risk analysis showed that inhalation of Pb could result in cancer for one or two persons per million of population in the Korean peninsula.
Show more [+] Less [-]Thorough analysis of polyhalogenated compounds in ray liver samples off the coast of Rio de Janeiro, Brazil Full text
2012
Rosenfelder, Natalie | Lehnert, Katja | Kaffarnik, Stefanie | Torres, Joao P. M. | Vianna, Marcelo | Vetter, Walter
INTRODUCTION: Five liver samples of two different ray species (Gymnura altavela and Zapteryx brevirostris) off the coast of Rio de Janeiro, Brazil, were analyzed for their pollution with anthropogenic and naturally occurring organohalogen compounds. MATERIAL AND METHODS: The samples were extracted with accelerated solvent extraction, and after a clean-up procedure, organohalogen compounds were separated by a modified group separation on activated silica. Subsequent analyses were done by targeted and non-targeted gas chromatography–mass spectrometry in the electron capture negative ion mode. RESULTS AND DISCUSSION: “Classic” organohalogen compounds such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and technical 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (DDT) were detected and quantified. PCBs generally exceeded the parts per million level and represented up to 90% of the total contamination of the ray livers. High concentrations were also detected for p,p′-DDE. Non-targeted full scan investigations lead to the detection of an abundant trichlorinated compound which was identified as a new DDT metabolite in biota. Different PBDE congeners and several halogenated natural products were quantified as well. In addition, polychlorinated terphenyls were identified and analyzed in the two species. Moreover, both ray species showed different fatty acid patterns and stable carbon isotope signatures. CONCLUSIONS: The two ray species showed high concentrations of organohalogen compounds in their liver tissue. Varied δ 13C values by up to 3.1‰ indicated that the two ray species were living in different habitats.
Show more [+] Less [-]Titania-based true heterogeneous photocatalysis Full text
2012
Herrmann, Jean-Marie
INTRODUCTION: This article recalls and demonstrates that heterogeneous photocatalysis belongs to heterogeneous catalysis according to its initial history. There are criteria, which have to be imperatively taken into account to deal with true (photo-)catalytic reactions. The photocatalytic activity, chosen as the reaction rate, is governed by five physical parameters (mass of catalyst, wavelength, initial concentrations (or pressures) of the reactants, temperature (around room temperature), and radiant flux). DISCUSSION: Once performed in optimal conditions, the reaction has to be characterized with (a) its quantum yield <QY> (ratio of the reaction rate to the incident photon flux), (b) the turnover number <TON> (number of molecules converted per active site during a given time), and (c) the turnover frequency <TOF> (<TON> per second). The true catalytic nature demands that the conversion provides a number of converted molecules higher than the “stoichiometric threshold” defined as the number of the active sites initially present on the catalyst, i.e., that <TON> be much greater than 1, and possibly than at least two or three orders of magnitude. Eventually, a complete mass balance determination should be established for all elements. It is shown that the main reaction intermediates are radicals. All these concepts and principles are illustrated by various examples (selective mild oxidation reactions, water pollutants elimination, and air purification), leading to a list of recommendations for performing really true catalytic reactions.
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