Search

Reactive intermediates formed upon irradiation of chromophoric dissolved organic matter (CDOM) contribute to the degradation of various organic contaminants in surface waters. Besides well-studied "short-lived" photo oxidants, such as triplet state CDOM (3CDOM*) or singlet oxygen, CDOM-derived "long-lived" photooxidants (LLPO) have been suggested as key players in the transformation of electron-rich contaminants. LLPO were hypothesized to mainly consist of phenoxyl radicals derived from phenolic moieties in the CDOM. To test this hypothesis and to better characterize LLPO, the transformation kinetics of selected target compounds (phenols and anilines) induced by a suite of electron-poor model phenoxyl radicals was studied in aerated aqueous solution at pH 8. The phenoxyl radicals were generated by photosensitized oxidation of the parent phenols using aromatic ketones as photosensitizers. Under steady-state irradiation, the presence of any of the electron-poor phenols lead to an enhanced abatement of the phenolic target compounds (at an initial concentration of 1.0 x 10(-7) M) compared to solutions containing the photosensitizer but no electron-poor phenol. A trend of increasing reactivity with increasing one-electron reduction potential of the electron-poor phenoxyl radical (range: 0.85-1.12 V vs. standard hydrogen electrode) was observed. Using the excited triplet state of 2-acetonaphthone as a selective oxidant for phenols, it was observed that the reactivity correlated with the concentration of electron-poor phenoxide present in solution. The rates of transformation of anilines induced by the 4-cyanophenoxyl radical were an order of magnitude smaller than for the phenolic target compounds. This was interpreted as a reduction of the radical intermediates back to the parent compound by the superoxide radical anion. Laser flash photolysis measurements confirmed the formation of the 4-cyanophenoxyl radical in solutions containing 2-acetonaphthone and 4-cyanophenol, and yielded values of (2.6 5.3) x 10(8) M-1 s(-1) for the second order rate constant for the reaction of this radical with 2,4,6-trimethylphenol. These and further results indicate that electron-poor model phenoxyl radicals generated through photosensitized oxidation are useful models to understand the photoreactivity of LLPO as part of the CDOM.

The accumulation of contaminants on the electrical devices could adversely affect the operation. The present work used photocatalytic functional material to coat on the surface of the electrical devices to prevent the influence of organic contamination. This kind of material was mainly composed of TiO 2 that can remove the contamination by the effect of photooxidation. The photocatalysis was affected by the strength of UV light and electric field. In the experiment, methyl orange (MO) was used as the organic contaminant. The effect of UV light and auxiliary electric field were analysed based on the theoretical simulation. With the stronger UV light, more electron–hole pairs were generated, photocatalytic effect became more pronounced. With the auxiliary electric field, the recombination of electron and hole could be restrained that would increase the productive rate of hole; therefore, more hydroxyl radical will be produced to degrade MO.

The composition of polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), and organophosphate flame retardants (OPFRs) present in the gas-phase fraction of the atmosphere of Barcelona was analyzed during the SARS-CoV-2 coronavirus disease (COVID-19) lockdown and prior to this period. The changes in daily concentrations of CO, NO, NO2, O3 and particulate matter smaller than 10 μm (PM10) were considered for comparison. Bayesian analysis considering serial dependencies and seasonality showed statistically significant decreases of CO, NO, NO2, and PM10 (between −28 and −76%) and O3 increases (+45%) during lockdown. However, the lockdown concentration decreases of PeCB (−90.5%, from 8.5 to 0.8 pg m–3), HCB (−79%, 25.5–5.4 pg m–3) and some PAHs, such as benz[a]anthracene (−87%, 120–17 pg m–3) and pyrene (−81%, 3,500–680 pg m–3), were even stronger. The PAH depletion ranged between −68 and −87% that could be primarily associated with the strong reduction of traffic mobility during this period (−80%). Besides traffic reduction, the observed air quality improvements could be related to lower generation of solid urban residues (−25%) and the subsequent decrease of urban waste incineration (between −25 and −28%). Tributyl phosphate also showed a reduction in concentration during lockdown but the other OPFRs were seemingly not affected by this restriction, possibly as a result of the uniform release from the emission sources, e.g., construction material, industrial applications, and household products., This work was supported by the Spanish Ministry of Science and Innovation (Projects: CUANTOX CTM2015-71832-P and INTEMPOL PGC2018-10228-B-I00). RP also acknowledges financial support from the Spanish Ministry of Science and Innovation (BES-2016-076339).

Soil mix cut-off walls have been increasingly used for containment of organic contaminants in polluted land. However, the mixed soil is susceptible to deterioration due to aggressive environmental and mechanical stresses, leading to crack-originated damage and requiring costly maintenance. This paper proposed a novel approach to achieve self-healing properties of soil mix cut-off wall materials triggered by the ingress of organic contaminants. Oil sorbent polymers with high absorption and swelling capacities were incorporated in a cementitious grout and mixed with soil using a laboratory-scale auger setup. The self-healing performance results showed that 500 &micro, m-wide cracks could be bridged and blocked by the swollen oil sorbents, and that the permeability was reduced by almost an order of magnitude after the permeation of liquid paraffin. It was shown by micro-CT scan tests that the network formed by the swollen oil sorbents acted as attachments and binder, preventing the cracked mixed soil sample from crumbling, and that the oil sorbents swelled three times in volume and therefore occupied the air space and blocked the cracks in the matrix. These promising results exhibit the potential for the oil sorbents to provide soil mix cut-off walls in organically-contaminated land with self-healing properties and enhanced durability.

Hemp (Cannabis sativa L.) seedlings were used to remove from water the fungicide metalaxyl-M and the endocrine disruptor (EDC) bisphenol A (BPA) at concentrations ranging from 2 to 100 μg mL−1. In 7 days of exposure, despite the phytotoxicity of each compound that reduced elongation and biomass, the seedlings were able to remove between 67 and 94% of metalaxyl-M and between 86 and 95% of BPA. The amounts of metalaxyl-M and BPA extracted from plant dry biomass were in the range of 106–3861 μg g−1 and 16–101 μg g−1, respectively, and resulted positively correlated to both the dose of compound added (P ≤ 0.01) and the amount removed by the plants (P ≤ 0.01). Plant uptake and transformation were the main mechanisms involved in the removal of the compounds. In another set of experiments, hemp was used to remove a mixture of two pesticides, metalaxyl-M and metribuzin, and three EDCs, BPA, 17β-estradiol (E2), and 4-tert-octylphenol (OP), at concentrations of 10, 10, 10, 10, and 1 μg g−1, respectively, from soil column not added and added with 2.5% (w/w) of a green compost (CM) or a wood biochar (BC). In 25 days, plants did not alter considerably the distribution of the compounds along the soil profile and were capable of removing, on average, 12, 11, 10, 9, and 14% of metalaxyl-M, metribuzin, BPA, E2, and OP, respectively. During growth, hemp transformed the compounds and accumulated part of them (except OP) mainly in the shoots. CM and, especially, BC significantly protected the plants from the toxicity of the compounds and enhanced the retention of the latter in soil, contrasting leaching. Thus, the single or synergistic use of hemp and amendments deserves attention being a very low-cost and eco-sustainable strategy to remediate water and soil.

Great attention has been paid to using biochar as soil conditioner and bio-accumulator. Nevertheless, biochar application in agriculture might cause a potential hazard to ecosystems, considering that toxic organic pollutants present in biochar may enter the environment. European Biochar Certificate (EBC) set certain criteria for biochar production. Achieving the EBC established values of the molar ratio of H/Corg 0.1, inhibition of Sinapis alba

The dyestuffs used in the textile sector are among the major pollutants and present as a polluting agent in the waters poured to the environment. Therefore, synthetic dyes led to the serious environmental pollution and threats to human health. The process of color removal from waste water of the textile industry is gaining importance from ecological point of view. Nowadays, the removal of dye materials is carried out by physical and chemical methods. However, the high cost of these methods and the resulting large amount of concentrated slurry causes problems. In recent years, it has been shown that white rot fungi have the ability to reduce the synthetic dye materials with their extracellular ligninolytic enzymes. Fungal biosorption is an economical, easy and efficient method for removing organic contaminants from aqueous media. In this study; the white rot fungus M. esculenta was immobilized into five different support materials (gelatin, polyurethane, kaolin, cellulose) and the removal of Reactive Orange 16 dye with these immobilized cells was investigated and compared. The best biological degradation of the dye was obtained by immobilization into polyurethane support material with M. esculenta (dye concentration: 10 mgL −1 ) 90,38%. Samples were analyzed in FT-IR to determine possible metabolites that can be occurred as a result of biodegradation. The M. esculenta laccase, which may be responsible for biodegradation, was partially purified and identified by SDS-PAGE. © 2017 Elsevier Ltd

The sorption of some benzene derivatives: o-xylene, toluene, phenol, benzyl alcohol, resorcinol and hydroquinone onto a zeolitic tuff-humic acid adduct (PCT-ImHA) was analysed by batch technique at 25°C and neutral pH. PCT-ImHA was prepared by binding leonardite-extracted humic acids (HA) to a zeolitic tuff sample rich in phillipsite and chabazite and enriched with Ca2+by cation exchange (Ca-PCT). The HA calcium salts were gently mixed with wet Ca-PCT; then, the mixture was heated at 330°C for 1.5h. An adduct with almost 2% of HA was obtained. The experimental data were well fitted by the Langmuir adsorption isotherm and showed that saturation capacity (qMax) increased with the octanol-water repartition coefficient (KO-W). The comparison with previous data on sorption onto immobilised HA highlights that qMaxvalues for PCT-ImHA are far higher than the sum of the contributions of the two separate components.

International audience; The dynamics of three classes of organic contaminants, namely n-alkanes, polycyclic aromatic hydrocarbons and polychlorinated biphenyls, were evaluated from the settled suspended particulate matter (SPM) of two waste-water treatment plant outlets (O1 and O2) at the Marseille coast. We used a 1-m-high Plexiglas settling column filled with 7 L of seawater to determine the particles' settling rates, size distribution, and the extent of organic contaminants. Six classes of SPM (50–200 μm particles size) were obtained from 15 fractions of 500-mL successive filtering samples ranging from 30 s to 5 days, including those in the tube wall. The results of the experiment indicated that N 68% of the particles settled within 15 min, which highly correlated with the distribution of organic carbon and contaminant contents. Furthermore, we demonstrated that 9%–13% of the SPM, which contained 5%–11% of the organic contaminants, are non-settable even after 5 days. Extrapolating such behaviour in situ using molecular diagnostic indices for organic contaminant source apportionment indicated that these non-settable contaminant particles are exported to the sea.

Enhanced phytoremediation adding biodegradable amendments like low molecular weight organic acids and surfactants is an interesting area of current research to overcome the limitation that represents low bioavailability of pollutants in soils. However, prior to their use in assisted phytoremediation, it is necessary to test if amendments per se exert any toxic effect to plants and to optimize their application mode. In this context, the present study assessed the effects of citric acid and Tween (R) 80 (polyethylene glycol sorbitan monooleate) on the development of alfalfa (Medicago sativa) plants, as influenced by their concentration and frequency of application, in order to evaluate the feasibility for their future use in enhanced phytoremediation of multi-contaminated soils. The results showed that citric acid negatively affected plant germination, while it did not have any significant effect on biomass or chlorophyll content. In turn, Tween (R) 80 did not affect plant germination and showed a trend to increase biomass, as well as it did not have any significant effect on chlorophyll levels. M. sativa appeared to tolerate citric acid and Tween (R) 80 at the tested concentrations, applied weekly. Consequently, citric acid and Tween (R) 80 could potentially be utilized to assist phytoremediation of contaminated soils vegetated with M. sativa.

The excessive use of phthalates (PHEs) plasticizers has promoted a serious environmental problem. This study evaluated the biodegradation of PHEs from polyvinyl chloride (PVC) film, aiming to mitigate damage to the environment. Therefore, 23 microorganisms were prospected and isolated from the Serra do Ouro Branco State Park (Minas Gerais, Brazil), where screening was carried out by growth in enriched microbial medium and esterase-activity was monitored by diffusion in solid agar. Three microorganisms were selected. Bacterium (I) presented the highest esterase activity, as evidenced in the diffusion tests in solid medium. Further, evidence of this is given by the biodegradation of PHEs into phthalic acid, because changes the acid concentration from 0 to 3.10 ± 0.07 mol L-1 and 28 % mass reduction of PVC film after 24 days. Furthermore, after six days of biodegradation the number of viable cells and ammonia concentration showed no significant change. This indicates that the survival of the Bacterium (I) cells is independent of ammonia consumption, but rather depends on PHEs consumption. The detection of the organic functions of -COOH and –COOR proved the biodegradation of PHEs by Bacterium (I), thus demonstrating its potential to be used in bioremediation of soils and rivers from PHEs contaminants.

A one-dimensional model was developed to investigate the transport of organic acids (commonly found in landfill leachate) through a partially saturated composite liner system beneath a landfill. Specific attention was paid to the influence of water content distribution on aqueous-phase diffusion process. Composite liner system was investigated, which was consisted of a geomembrane and a compacted clay liner underlain by three kinds of attenuation layer: sand layer, sandy clay loam layer, and clay layer. Volumetric water content profile in soil layers was obtained by Van Genuchten model, and the Millington and Quirk model was employed to describe the non-linear relationship between volumetric water content and diffusion coefficient. Three cases were analyzed and compared, i.e., totally saturated condition, unsaturated condition without considering unsaturated diffusion model, and unsaturated condition considering unsaturated diffusion model. The numerical results show that the unsaturated sand attenuation layer could serve as excellent diffusion barrier to organic contaminant due to its low water retention capacity. When the dependence of diffusion coefficient on volumetric water content is sufficiently considered, the contaminant flux decreases significantly in all the three kinds of attenuation layer. Unsaturated diffusion model capturing the relationship between water content and diffusion coefficient enables a more reasonable prediction of contaminant transport and distribution in soils.

Synthetic chemical compounds, such as organochlorines, are known for their persistence and toxicity. The diet represents, for the general population, the main route of exposure to these contaminants, because organochlorines in food constitute a significant health risk, and olive oil has a high consumption rate among people of the producing countries; the control of residues in olive oil is of great importance. In this study, the presence of residues of hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) was assessed in samples of extra-virgin olive oil from Tuscany (central Italy). The analyses revealed the presence of HCB in concentrations below the detection limit; DDT and PCBs were instead present in all samples tested, and PCB concentrations were always higher than those of DDT, from 1.24 to 29.35, and from 0.01 to 1.83 ng/g wet weight, respectively. PRACTICAL APPLICATIONS Because organochlorines in food constitute a significant health risk, and olive oil has a high consumption rate among people of the producing countries, the control of residues in olive oil is of great importance. For the first time here, we present data on organochlorine pollution in oil samples collected in Tuscany, and assess the intake ranges of pollutants related to consumption of the oils analyzed. Showing the low contamination levels of Tuscan olive oil, we wish to confirm the high quality of this kind of food lipid.

Water resources are directly and indirectly affected by anthropogenic activities (e.g., changes in land use) and natural factors (e.g., climate change), that is, global change. The Mediterranean basin is one of the most vulnerable regions of the world to global change, and one of the “hot spots” for forthcoming problems of water availability. The present review provides an overview about the relationship between chemical quality (especially concerning organic microcontaminants) and water scarcity, particularly in the Mediterranean area. We include an overview of environmental contaminants and analytical methodologies and consider the fate and the behavior of organic contaminants, and the effects of pollutants on ecosystems., This work was supported by the Spanish Ministry of Science and Innovation through the Consolider-Ingenio 2010 CSD2009-00065 project.

Et utvalg av miljøgifter som tilføres Bærumsbassenget fra overvann og Sandviksvassdraget har blitt kartlagt. Tilførslene av organiske miljøgifter ble beregnet på basis av målinger utført ved hjelp av passive prøvetakere og en kontinuerlig vannstrømssentrifuge. For metaller ble beregningene gjort etter konvensjonell prøvetakning. Prøvetakning ble utført ved ulike tidsrom for å gjenspeile mulige sesongvariasjoner. Følgende tilførsler fra Sandviksvassdraget til Bærumsbassenget ble beregnet: PCB7

Adsorption mechanisms of toxic non-ionic organic contaminants (NOCs), aniline and nitrobenzene, with natural-zeolite and organo-zeolite (OZ) were investigated in both batch and continuous systems. In batch tests, the adsorption capacity of aniline and nitrobenzene onto natural zeolite surface is very low or almost nil but becomes significant upon modifying the zeolite surface by hexadecyltrimethylammonium (HDTMA). A partitioning mechanism is proposed to be responsible for the adsorption of NOCs onto OZ. The effectiveness of the partitioning mechanism is directly connected with hydrophobic properties of the NOCs. The column tests were carried out as an indicator for continuous system. The breakthrough curves were constructed for OZ/NOC system and the adsorption capacity of NOCs onto OZ under the present conditions were determined as 2.36 and 3.25 mg per gram of OZ, for aniline and nitrobenzene, respectively. A schematic model is proposed to account for the adsorption of NOCs onto OZ.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2000, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2000, Bu çalışma iki aşamada gerçekleştirilmiştir. Birinci aşamada hem kesikli sistemde (şişede) ve hem de kesiksiz sistemde (kolonda) olmak üzere, kuaterner amin grubu farklı zincir uzunluğuna sahip yüzey aktif maddelerin [HTAB: R(CH3)3NBr, R:C16H33 ; TTAB: R(CH3)3NBr, R: C14H29; DTAB: R(CH3)3NBr, R: C12H25] klinoptilolit üzerine adsorpsiyon mekanizmaları detaylı bir şekilde incelenerek Modifiye Frumkin ve Langmuir modeline göre termodinamik parametreleri belirlenmiş ve böylece klinptilolit yüzeyinin modifiye edilmesinde kullanılacak yüzey aktif madde (YAM) tesbit edilmiştir. İkinci aşamada ise tesbit edilen bu YAM (HTAB) ile klinoptilolit yüzeyi modifiye edilerek organo-klinoptilolit (modifiye klinoptilolit) hazırlanmıştır. Sonra kesikli ve kesiksiz sistemde hem doğal klinoptilolit (DK) ve hem de organo-klinoptilolit (OK) üzerine , sıvı atıklarda bulunan ve toksik etkiye sahip olan anilin ve nitrobenzen türü organik kirleticilerin adsorplanma mekanizmaları incelenerek Freundlich modeline göre adsorpsiyon serbest enerjileri ve adsorpsiyon sabitleri belirlenmiştir. Elde edilen sonuçlardan bazıları şunlardır; I) YAM’lerin klinoptilolit üzerine adsorpsiyonu ağırlıklı olarak iyon değiştirme ve hidrofobik (zincir-zincir) etkileşim mekanizmaları ve daha az oranda da elektrostatik etkileşim mekanizmaları ile gerçekleşmektedir, II) 16 karbon zinciri ile en fazla zincir uzunluğuna sahip HTAB, 14 karbon zincirli TTAB ve 12 karbon zincirli DTAB’a göre klinoptilolit yüzeyine daha çok adsorplanmaktadır, III) Modifiye Frumkin modeline göre HTAB, TTAB ve DTAB’a ait adsorpsiyon serbest enerjisi (Gads) değerleri sırasıyla –37.64, -33.86 ve -33.74 kJ/mol’dür, IV) Kolon reaktörde elde edilen klinoptilolit üzerine HTAB adsorpsiyon kapasitesi 4.39 mg/cm3’dür, V) DK üzerine anilin ve nitrobenzen adsorpsiyon kapasitesi çok düşük düzeyde iken HTAB ile klinoptilolit yüzeyinin modifiye edilmesi ve organo-klinoptilolitin hazırlanmasıyla bu kapasite çok yüksek oranda artmaktadır, VI) Freundlich modeline göre OK üzerine nitrobenzen ve anilin adsorpsiyonu serbest enerji (G) değerleri sırasıyla –10.51 ve –4.94 kJ/mol’dür, VII) Kolonda OK üzerine nitrobenzen ve anilin adsorpsiyon kapasiteleri sırasıyla 0.57 ve 0.47 mg/cm3’dür., This study consists of two parts. In the first part, the adsorption mechanisms of quaternary ammonium surface active agents of different chain length i.e. HTAB, TTAB and DTAB onto clinoptilolite were investigated in both batch and continuous systems. The effect of conditioning time, solids concentration, pH, concentration and temperature on the adsorption of quaternary amines onto clinoptilolite surface was systematically studied. In the second part, the clinoptilolite surface was modified by HTAB thus in order to produce organo-clinoptilolite. Then, The adsorption mechanisms of toxic organic chemicals, aniline and nitrobenzene, which are present in wastewater or underground water with organo-clinoptilolite and natural clinoptilolite were investigated in batch and continuous systems. Thermodynamic parameters using Modified Frumkin and Langmuir models were utilized to obtain the adsorption free energies and heat of adsorption. Some of the conclusions are as follows; I) The adsorption mechanisms of quaternary amines exhibit two distinct regions involving ion exchange and hydrophobic (chain-chain) interaction mechanisms; the contribution of electrostatic interaction is minimal, II) The adsorption density increases with increasing the chain hydrocarbon length, III) The adsorption free energies (Gads) of HTAB, TTAB and DTAB for modified Frumkin model –37.64, -33.86 and -33.74 kJ/mol, respectively. IV) The adsorbed amount of HTAB onto natural clinoptilolite in column is 4.39 mg/cm3. V) Adsorption capacities of aniline and nitrobenzene onto clinoptilolite is very low but when clinoptilolite surface was modified by HTAB its adsorption capacity increased significantly, VI) The adsorption free energies (Gads) of aniline and nitrobenzene onto organo-clinoptilolite for Freundlich model are -4.94 and -10.51 kJ/mol, respectively. VII) The adsorption amount of nitrobenzene and aniline onto organo-clinoptilolite in column are 0.57 and 0.47 mg/cm3, respectively. The results generally reveal the importance of ion exchange and hydrophobic interactions in the system., Yüksek Lisans, M.Sc.