Refinar búsqueda
Resultados 1411-1420 de 2,513
Demonstrating a New BiOCl₀.₈₇₅Br ₀.₁₂₅ Photocatalyst to Degrade Pharmaceuticals Under Solar Irradiation Texto completo
2014
Lester, Yaal | Avisar, Dror | Gnayem, Hani | Sasson, Y. (Yoel) | Shavit, Michal | Mamane, Hadas
This study demonstrates the potential of a new BiOCl₀.₈₇₅Br₀.₁₂₅ photocatalyst to degrade pharmaceuticals in water (i.e., carbamazepine (CBZ), ibuprofen (IBF), bezafibrate (BZF), and propranolol (PPL)), under simulated solar irradiation. Different parameters were examined through their influence on CBZ degradation. Increasing the catalyst concentration up to 500 mg/L increased CBZ degradation rate; however, above 500 mg/L, CBZ degradation rate was slightly reduced, most likely due to the catalyst’s light-screening effect at high concentrations. Increasing the pH of the tested solution from 4 to 9 decreased the degree of CBZ adsorption to the catalyst and consequently its degradation rate. Quantum yield for CBZ degradation was found to be 0.75 ± 0.05 % using an integrating sphere for absorbance measurements to correctly account for scattering of light by the suspended catalyst. Degradation rates of all examined compounds (at pH 7) followed the order PPL > BZF > IBF > CBZ (highest rate for PPL). Interestingly, PPL was least adsorbed to the catalyst, implying that adsorption is not always mandatory for efficient degradation with BiOCl₀.₈₇₅Br₀.₁₂₅. Different adsorption mechanisms were hypothesized for the different pharmaceuticals, including hydrophobic attraction for the neutrally charged CBZ and ion exchange for the negatively charged IBF and BZF.
Mostrar más [+] Menos [-]The Multixenobiotic Resistance Mechanism in Species of Invertebrates Associated to an Urban Stream in the Patagonia Mountain Texto completo
2014
Assef, Yanina Andrea | Miserendino, María Laura | Horak, Cristina Natalia
The Multixenobiotic Resistance Mechanism in Species of Invertebrates Associated to an Urban Stream in the Patagonia Mountain Texto completo
2014
Assef, Yanina Andrea | Miserendino, María Laura | Horak, Cristina Natalia
There are multiple stressors derived from urbanizations that result in frequent disturbances on streams and rivers reducing water quality and threatens aquatic biota. P-glycoprotein (P-gp)-mediated multixenobiotic resistance (MXR) is a defence mechanism analogous to multidrug resistance (MDR), which has been demonstrated in several aquatic organisms. This system protects cells against the entry and the accumulation of xenobiotics and has been proposed as a biomarker for pollution assessment. We conducted a study in a post-urban reach of Esquel stream (Chubut Province) downstream a wastewater treatment plant, in order to assess the presence and activity of MXR in five freshwater macroinvertebrate species (Helobdella michaelseni, Helobdella simplex, Patagoniobdella variabilis, Hyalella curvispina and Chironomus riparius). We measured the accumulation of the model P-gp substrate rhodamine B (RB) in organisms previously exposed to pollution. Our results described the activity of the MXR system in the three species of leeches suggesting their suitability as the in vivo biomonitoring. We also identified a dependence of the transporter activity with the development stage in H. simplex, highlighting the importance of using organisms of similar size classes since it may affect observed results. Finally, we concluded that benthic freshwater macroinvertebrates possess different species-specific levels of MXR activity possibly influencing their natural distribution as well as their survival.
Mostrar más [+] Menos [-]The multixenobiotic resistance mechanism in species of invertebrates associated to an urban stream in the Patagonia mountain Texto completo
2014
Assef, Yanina Andrea | Miserendino, Maria Laura | Horak, Cristina Natalia
There are multiple stressors derived from urbanizations that result in frequent disturbances on streams and rivers reducing water quality and threatens aquatic biota. P-glycoprotein (P-gp)-mediated multixenobiotic resistance (MXR) is a defence mechanism analogous to multidrug resistance (MDR), which has been demonstrated in several aquatic organisms. This system protects cells against the entry and the accumulation of xenobiotics and has been proposed as a biomarker for pollution assessment. We conducted a study in a post-urban reach of Esquel stream (Chubut Province) downstream a wastewater treatment plant, in order to assess the presence and activity of MXR in five freshwater macroinvertebrate species (Helobdella michaelseni, Helobdella simplex, Patagoniobdella variabilis, Hyalella curvispina and Chironomus riparius). We measured the accumulation of the model P-gp substrate rhodamine B (RB) in organisms previously exposed to pollution. Our results described the activity of the MXR system in the three species of leeches suggesting their suitability as the in vivo biomonitoring. We also identified a dependence of the transporter activity with the development stage in H. simplex, highlighting the importance of using organisms of similar size classes since it may affect observed results. Finally, we concluded that benthic freshwater macroinvertebrates possess different species-specific levels of MXR activity possibly influencing their natural distribution as well as their survival. | Fil: Assef, Yanina Andrea. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina | Fil: Miserendino, Maria Laura. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina | Fil: Horak, Cristina Natalia. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina
Mostrar más [+] Menos [-]The Air Quality in African Rural Environments. Preliminary Implications for Health: The Case of Respiratory Disease in the Northern Benin Texto completo
2014
De Longueville, Florence | Hountondji, Yvon | Ozer, Pierre | Henry, Sabine
The Air Quality in African Rural Environments. Preliminary Implications for Health: The Case of Respiratory Disease in the Northern Benin Texto completo
2014
De Longueville, Florence | Hountondji, Yvon | Ozer, Pierre | Henry, Sabine
Recently, the World Health Organization’s International Association for Research on Cancer classified outdoor air pollution as carcinogenic to humans and puts air pollution in the same category as tobacco smoke, UV radiation, and plutonium. The ambient air is polluted by emissions from motor vehicles, industrial processes, power generation, household combustion of solid fuel, and other sources. Dust storms lead to particulate levels that exceed internationally recommended levels, especially near the Sahara. However, this source of air pollution appears to be under-studied, particularly in the literature devoted to human health impacts in West Africa. More than 50 % of the total dust emitted into the atmosphere comes from the Sahara. These aerosols contribute to increase the concentrations of particles smaller than 10 μm (PM₁₀), which are breathable particles. This study is the first designed to assess the real impact of Saharan dust on air quality and respiratory health of children in a region of West Africa. Dust events having affected the Northern Benin during the dry seasons between 2003 and 2007 were determined. The analyzed health data are the monthly rates of acute lower respiratory infections (ALRI). Over the entire study period, 61 days of dust events were observed in the region. They recorded on average a daily PM₁₀concentration of 1017 μg m⁻³, more than 18 times higher than that calculated on all days without dust events. The study also highlighted a mean increase of 12.5 % of ALRI rates during the months recording dust events. The use of daily health data should help to refine these initial results in the future.
Mostrar más [+] Menos [-]The Air Quality in African Rural Environments. Preliminary Implications for Health: The Case of Respiratory Disease in the Northern Benin Texto completo
2014
De Longueville, Florence | Hountondji, Yvon-Carmen | Ozer, Pierre | Henry, Sabine
peer reviewed | Recently, the World Health Organization’s International Association for Research on Cancer classified outdoor air pollution as carcinogenic to humans and puts air pollution in the same category as tobacco smoke, UV radiation, and plutonium. The ambient air is polluted by emissions from motor vehicles, industrial processes, power generation, household combustion of solid fuel, and other sources. Dust storms lead to particulate levels that exceed internationally recommended levels, especially near the Sahara. However, this source of air pollution appears to be under-studied, particularly in the literature devoted to human health impacts in West Africa. More than 50 % of the total dust emitted into the atmosphere comes from the Sahara. These aerosols contribute to increase the concentrations of particles smaller than 10 μm (PM10), which are breathable particles. This study is the first designed to assess the real impact of Saharan dust on air quality and respiratory health of children in a region of West Africa. Dust events having affected the Northern Benin during the dry seasons between 2003 and 2007 were determined. The analyzed health data are the monthly rates of acute lower respiratory infections (ALRI). Over the entire study period, 61 days of dust events were observed in the region. They recorded on average a daily PM10 concentration of 1017 μg m−3, more than 18 times higher than that calculated on all days without dust events. The study also highlighted a mean increase of 12.5 % of ALRI rates during the months recording dust events. The use of daily health data should help to refine these initial results in the future.
Mostrar más [+] Menos [-]Effects of Emissions from an Aluminium Smelter in a Tree Tropical Species Sensitive to Fluoride Texto completo
2014
Sant’Anna-Santos, Bruno Francisco | Azevedo, Aristéa Alves | Alves, Thiago Gonçalves | Campos, Naiara Viana | Oliva, Marco Antônio | Valente, Vânia Maria Moreira
Effects of Emissions from an Aluminium Smelter in a Tree Tropical Species Sensitive to Fluoride Texto completo
2014
Sant’Anna-Santos, Bruno Francisco | Azevedo, Aristéa Alves | Alves, Thiago Gonçalves | Campos, Naiara Viana | Oliva, Marco Antônio | Valente, Vânia Maria Moreira
Fluoride is among the most phytotoxic atmospheric pollutants, commonly linked to the appearance of lesions in susceptible plants around emitting sources. In order to assess the effects of fluoride on leaves of Spondias dulcis Parkinson (Anacardiaceae), plants were examined 78 km (non-polluted area) and 0.78 km (polluted area) from an aluminium smelter. The level of fluoride increased with the exposure time of the plants in the polluted area. On the third day of exposure in the polluted area, necroses with typical colouration were observed. Micromorphological damage began at the abaxial epidermis, mainly associated with the stomata. Starch grain accumulation was more pronounced in the midrib. The cell membranes and chloroplasts were greatly affected by the pollutant. We observed accumulation of phenolic compounds and electron-dense material at the boundaries of the ending veinlets. The microscopic events described precede the appearance of symptoms and are therefore of prognostic value in predicting injury by fluoride and will be useful as biomarkers. The high sensitivity of S. dulcis to fluoride and the specificity of the symptoms confirm, for the first time, in an experiment of active biomonitoring, the potential of this species as a bioindicator.
Mostrar más [+] Menos [-]Effects of emissions from an aluminium smelter in a tree tropical species sensitive to fluoride Texto completo
2014
Sant’Anna-Santos, Bruno Francisco | Azevedo, Aristéa Alves | Alves, Thiago Gonçalves | Campos, Naiara Viana | Oliva, Marco Antônio | Valente, Vânia Maria Moreira
Fluoride is among the most phytotoxic atmospheric pollutants, commonly linked to the appearance of lesions in susceptible plants around emitting sources. In order to assess the effects of fluoride on leaves of Spondias dulcis Parkinson (Anacardiaceae), plants were examined 78 km (non-polluted area) and 0.78 km (polluted area) from an aluminium smelter. The level of fluoride increased with the exposure time of the plants in the polluted area. On the third day of exposure in the polluted area, necroses with typical colouration were observed. Micromorphological damage began at the abaxial epidermis, mainly associated with the stomata. Starch grain accumulation was more pronounced in the midrib. The cell membranes and chloroplasts were greatly affected by the pollutant. We observed accumulation of phenolic compounds and electron-dense material at the boundaries of the ending veinlets. The microscopic events described precede the appearance of symptoms and are therefore of prognostic value in predicting injury by fluoride and will be useful as biomarkers. The high sensitivity of S. dulcis to fluoride and the specificity of the symptoms confirm, for the first time, in an experiment of active biomonitoring, the potential of this species as a bioindicator.
Mostrar más [+] Menos [-]Land Use Specific Ammonia Deposition Velocities: a Review of Recent Studies (2004–2013) Texto completo
2014
Schrader, Frederik | Brümmer, Christian
Land Use Specific Ammonia Deposition Velocities: a Review of Recent Studies (2004–2013) Texto completo
2014
Schrader, Frederik | Brümmer, Christian
Land use specific deposition velocities of atmospheric trace gases and aerosols—particularly of reactive nitrogen compounds—are a fundamental input variable for a variety of deposition models. Although the concept is known to have shortcomings—especially with regard to bi-directional exchange—the often limited availability of concentration data and meteorological input variables make it a valuable simplification for regional modeling of deposition fluxes. In order to meet the demand for an up-to-date overview of recent publications on measurements and modeling studies, we compiled a database of ammonia (NH₃) deposition velocities published from 2004 to 2013. Observations from a total of 42 individual studies were averaged using an objective weighing scheme and classified into seven land use categories. Weighted average and median deposition velocities are 2.2 and 2.1 cm s⁻¹for coniferous forests, 1.5 and 1.2 cm s⁻¹for mixed forests, 1.1 and 0.9 cm s⁻¹for deciduous forests, 0.9 and 0.7 cm s⁻¹for semi-natural sites, 0.7 and 0.8 cm s⁻¹for urban sites, 0.7 and 0.6 cm s⁻¹for water surfaces, and 1.0 and 0.4 cm s⁻¹for agricultural sites, respectively. Thus, values presented in this compilation were considerably lower than those found in former studies (e.g., VDI 2006). Reasons for the mismatch were likely due to different land use classification, different averaging methods, choices of measurement locations, and improvements in measurement and in modeling techniques. Both data and code used for processing are made available as supplementary material to this article.
Mostrar más [+] Menos [-]Land use specific ammonia deposition velocities: a review of recent studies (2004-2013) Texto completo
2014
Schrader, Frederik | Brümmer, Christian
Land use specific deposition velocities of atmospheric trace gases and aerosolsparticularly of reactive nitrogen compoundsare a fundamental input variable for a variety of deposition models. Although the concept is known to have shortcomingsespecially with regard to bi-directional exchangethe often limited availability of concentration data and meteorological input variables make it a valuable simplification for regional modeling of deposition fluxes. In order to meet the demand for an up-to-date overview of recent publications on measurements and modeling studies, we compiled a database of ammonia (NH3) deposition velocities published from 2004 to 2013. Observations from a total of 42 individual studies were averaged using an objective weighing scheme and classified into seven land use categories. Weighted average and median deposition velocities are 2.2 and 2.1 cm s-1 for coniferous forests, 1.5 and 1.2 cm s-1 for mixed forests, 1.1 and 0.9 cm s-1 for deciduous forests, 0.9 and 0.7 cm s-1 for semi-natural sites, 0.7 and 0.8 cm s-1 for urban sites, 0.7 and 0.6 cm s-1 for water surfaces, and 1.0 and 0.4 cm s-1 for agricultural sites, respectively. Thus, values presented in this compilation were considerably lower than those found in former studies (e.g., VDI 2006). Reasons for the mismatch were likely due to different land use classification, different averaging methods, choices of measurement locations, and improvements in measurement and in modeling techniques. Both data and code used for processing are made available as supplementary material to this article.
Mostrar más [+] Menos [-]Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008 Texto completo
2014
Garmo, Øyvind A. | Skjelkvåle, Brit Lisa | de Wit, Heleen A. | Colombo, Luca | Curtis, Chris | Fölster, Jens | Hoffmann, Andreas | Hruška, Jakub | Høgåsen, Tore | Jeffries, Dean S. | Keller, W Bill | Krám, Pavel | Majer, Vladimír | Monteith, Don T. | Paterson, Andrew M. | Rogora, Michela | Rzychoń, Dorota | Steingruber, Sandra | Stoddard, John L. | Vuorenmaa, Jussi | Worsztynowicz, Adam
Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008 Texto completo
2014
Garmo, Øyvind A. | Skjelkvåle, Brit Lisa | de Wit, Heleen A. | Colombo, Luca | Curtis, Chris | Fölster, Jens | Hoffmann, Andreas | Hruška, Jakub | Høgåsen, Tore | Jeffries, Dean S. | Keller, W Bill | Krám, Pavel | Majer, Vladimír | Monteith, Don T. | Paterson, Andrew M. | Rogora, Michela | Rzychoń, Dorota | Steingruber, Sandra | Stoddard, John L. | Vuorenmaa, Jussi | Worsztynowicz, Adam
Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analysed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (SO₄*) declined significantly between 1990 and 2008 (−15 to −59 %). In contrast, regional and temporal trends in nitrate were smaller and less uniform. In 11 of 12 regions, chemical recovery was demonstrated in the form of positive trends in pH and/or alkalinity and/or acid neutralising capacity (ANC). The positive trends in these indicators of chemical recovery were regionally and temporally less distinct than the decline in SO₄* and tended to flatten after 1999. From an ecological perspective, the chemical quality of surface waters in acid-sensitive areas in these regions has clearly improved as a consequence of emission abatement strategies, paving the way for some biological recovery.
Mostrar más [+] Menos [-]Trends in surface water chemistry in acidified areas in Europe and North America from 1990 to 2008 Texto completo
2014
Garmo, Øyvind Aaberg | Skjelkvåle, Brit Lisa | de Wit, Heleen | Colombo, Luca | Curtis, Chris | Fölster, Jens | Hoffmann, Andreas | Hruška, Jakub | Høgåsen, Tore | Jeffries, Dean S. | Keller, W. Bill | Krám, Pavel | Majer, Vladimir | Monteith, Don T. | Paterson, Andrew M. | Rogora, Michela | Rzychon, Dorota | Steingruber, Sandra | Stoddard, John L. | Vuorenmaa, Jussi | Worsztynowicz, Adam
Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analysed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (SO4*) declined significantly between 1990 and 2008 (−15 to −59 %). In contrast, regional and temporal trends in nitrate were smaller and less uniform. In 11 of 12 regions, chemical recovery was demonstrated in the form of positive trends in pH and/or alkalinity and/or acid neutralising capacity (ANC). The positive trends in these indicators of chemical recovery were regionally and temporally less distinct than the decline in SO4* and tended to flatten after 1999. From an ecological perspective, the chemical quality of surface waters in acid-sensitive areas in these regions has clearly improved as a consequence of emission abatement strategies, paving the way for some biological recovery. | acceptedVersion
Mostrar más [+] Menos [-]Leaching of Dissolved Organic Carbon and Trace Elements After Stem-Only and Whole-Tree Clear-cut on Boreal Peatland Texto completo
2014
Kiikkilä, Oili | Nieminen, Tiina M. | Starr, Mike | Mäkilä, Markku | Loukola-Ruskeeniemi, Kirsti | Ukonmaanaho, Liisa
Leaching of Dissolved Organic Carbon and Trace Elements After Stem-Only and Whole-Tree Clear-cut on Boreal Peatland Texto completo
2014
Kiikkilä, Oili | Nieminen, Tiina M. | Starr, Mike | Mäkilä, Markku | Loukola-Ruskeeniemi, Kirsti | Ukonmaanaho, Liisa
The aim of this work was to study the short-term effect of clear-cut harvest on concentrations of dissolved organic carbon (DOC), B, Al, Zn, Cu, Ni, Cr, Cd and Pb in drainage water from northern peatland catchments in Finland underlain by granitic or black shale bedrock, the latter having higher concentrations of several trace elements, such as Ni and Zn. Stem-only harvest (SOH) or whole-tree harvest (WTH) with stump removal were carried out at coniferous sites. Controls were left unharvested. DOC and trace element concentrations were monitored during one pre-treatment and two post-treatment years. There was no constant increase in the element concentrations. However, there were signs that both SOH and WTH clear-cut harvest on northern peatland catchments increases the concentrations of DOC, B, Al, Zn and Ni in ditchwater in some sites irrespective of the bedrock type. The greatest increases were observed in WTH sites but the study does not allow us to assess the statistical significance of the magnitude of the difference between SOH and WTH. We conclude that the element concentrations in ditchwater depend largely on site characteristics masking the possible effect of harvest.
Mostrar más [+] Menos [-]Leaching of dissolved organic carbon and trace elements after stem-only and whole-tree clear-cut on boreal peatland Texto completo
2014
Kiikkilä, O. | Nieminen, T.M. | Starr, M. | Mäkilä, M. | Loukola-Ruskeeniemi, K. | Ukonmaanaho, L. | Metsäntutkimuslaitos
Enhancing aerobic digestion potential of municipal waste-activated sludge through removal of extracellular polymeric substance Texto completo
2014
Merrylin, J. | Kaliappan, S. | Kumar, S Adish | Yeom, Ick-Tae | Banu, J Rajesh
A protease-secreting bacteria was used to pretreat municipal sewage sludge to enhance aerobic digestion. To enhance the accessibility of the sludge to the enzyme, extracellular polymeric substances were removed using citric acid thereby removing the flocs in the sludge. The conditions for the bacterial pretreatment were optimized using response surface methodology. The results of the bacterial pretreatment indicated that the suspended solids reduction was 18 % in sludge treated with citric acid and 10 % in sludge not treated with citric acid whereas in raw sludge, suspended solids reduction was 5.3 %. Solubilization was 10.9 % in the sludge with extracellular polymeric substances removed in contrast to that of the sludge with extracellular polymeric substances, which was 7.2 %, and that of the raw sludge, which was just 4.8 %. The suspended solids reduction in the aerobic reactor containing pretreated sludge was 52.4 % whereas that in the control reactor was 15.3 %. Thus, pretreatment with the protease-secreting bacteria after the removal of extracellular polymeric substances is a cost-effective and environmentally friendly method.
Mostrar más [+] Menos [-]Effectiveness of rodenticides for managing invasive roof rats and native deer mice in orchards Texto completo
2014
Baldwin, Roger A. | Quinn, Niamh | Davis, David H. | Engeman, Richard M.
Roof rats (Rattus rattus) and deer mice (Peromyscus maniculatus) are occasional pests of nut and tree fruit orchards throughout California and in many other parts of the USA and beyond. In general, the most practical and cost-effective control method for rodents in many agricultural environments is the use of rodenticides (toxic baits), but little or no information exists on the efficacy of current rodenticides in controlling roof rats and deer mice in orchards. Therefore, our goals were to develop an index of rodent activity to monitor efficacy of rodenticides and to subsequently test the efficacy of three California Department of Food and Agriculture rodenticide baits (0.005 % chlorophacinone treated oats, 0.005 % diphacinone treated oats, and 0.005 % diphacinone wax block) to determine their utility for controlling roof rats and deer mice in agricultural orchards. We determined that a general index using the number of roof rat photos taken at a minimum of a 5-min interval was strongly correlated to the minimum number known estimate of roof rats; this approach was used to monitor roof rat and deer mouse populations pre- and post-treatment. Of the baits tested, the 0.005 % diphacinone treated oats was most effective for both species; 0.005 % chlorophacinone grain was completely ineffective against roof rats. Our use of elevated bait stations proved effective at providing bait to target species and should substantially limit access to rodenticides by many non-target species.
Mostrar más [+] Menos [-]Silver-modified clinoptilolite for the removal of Escherichia coli and heavy metals from aqueous solutions Texto completo
2014
Akhigbe, Lulu | Ouki, Sabeha | Saroj, Devendra | Lim, Xiang Min
This paper investigates the potential of using the silver antibacterial properties combined with the metal ion exchange characteristics of silver-modified clinoptilolite to produce a treatment system capable of removing both contaminants from aqueous streams. The results have shown that silver-modified clinoptilolite is capable of completely eliminating Escherichia coli after 30-min contact time demonstrating its effectiveness as a disinfectant. Systems containing both E. coli and metals exhibited 100 % E. coli reduction after 15-min contact time and maximum metal adsorption removal efficiencies of 97, 98, and 99 % for Pb²⁺, Cd²⁺, and Zn²⁺respectively after 60 min; 0.182–0.266 mg/g of metal ions were adsorbed by the zeolites in the single- and mixed-metal-containing solutions. Nonmodified clinoptilolite showed no antibacterial properties. This study demonstrated that silver-modified clinoptilolite exhibited high disinfection and heavy metal removal efficiencies and consequently could provide an effective combined treatment system for the removal of E. coli and metals from contaminated water streams.
Mostrar más [+] Menos [-]