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1.
Molecules ; 28(15)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37570769

RESUMEN

The use of magnetic composites in wastewater treatment has become widespread due to their high flocculating characteristics and ferromagnetism. This review provides an analysis and summary of the preparation and application of magnetic composites through controllable assembly for use in wastewater treatment. The applications of magnetic composites include the treatment of dye wastewater, heavy metal wastewater, microalgae suspensions, and oily wastewater. Additionally, the recycling and regeneration of magnetic composites have been investigated. In the future, further research could be focused on improving the assembly and regeneration stability of magnetic composites, such as utilizing polymers with a multibranched structure. Additionally, it would be beneficial to explore the recycling and regeneration properties of these composites.

2.
Environ Sci Technol ; 56(5): 3106-3116, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-35147034

RESUMEN

Liquid crystal monomers (LCMs) are a class of emerging chemical pollutants; however, their release and gas-particle partitioning remain unknown. This study performed the first comprehensive analysis of a wide range of 93 LCMs in the ambient air of liquid crystal display (LCD) dismantling facilities. A total of 53 of the 93 target LCMs were detected in the air samples. The total atmospheric concentrations (gas and particles) of LCMs (∑LCMs) ranged from 68,800 to 385,000 (median of 204,000) pg/m3. Most LCMs were predominant in the gas phase, implying that their atmospheric transport would be mainly governed by gas rather than particle diffusions. Differential distribution patterns of the LCMs were observed due to their different atmospheric partitioning behaviors. Significant linear correlations were found between the gas-particle partitioning coefficients (KP) and the predicted subcooled vapor pressures (PL) and octanol-air partitioning coefficients (Koa) (p < 0.01). Compared with two equilibrium-state models, the experimentally observed particulate fractions (ϕ) fit better with the predicted values based on the Li-Ma-Yang (L-M-Y) steady-state model, and Koa was identified as a key factor determining the atmospheric fate pathways of LCMs. Our study highlights another new class of chemicals significantly contributing to the chemical mixture in the ambient air at e-waste recycling areas.


Asunto(s)
Contaminantes Atmosféricos , Residuos Electrónicos , Contaminantes Ambientales , Cristales Líquidos , Contaminantes Atmosféricos/análisis , Polvo/análisis , Residuos Electrónicos/análisis , Monitoreo del Ambiente , Contaminantes Ambientales/análisis , Reciclaje
3.
Environ Sci Technol ; 56(14): 10131-10140, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35786931

RESUMEN

Fluorescent brighteners (FBs) are extensively used as important chemical additives in multiple industrial fields worldwide. The history of the use of global FBs spans over 60 years, but knowledge on their environmental occurrence and risks remains largely unknown. Here, we screened indoor dust and hand wipes from South China for a broad suite of 17 emerging FBs using a new comprehensive analytical method. All 17 FBs were detected in the indoor environment for the first time, most of them having been rarely investigated or never reported in prior environmental studies. Ionic FBs were found to be more abundant than nonionic ones. The median total concentrations of the 17 detectable FBs reached 11,000 ng/g in indoor dust and 2640 ng/m2 in hand wipes, comparable to or higher than those of well-known indoor pollutants. Human exposure assessment indicated that hand-to-mouth contact is a significant pathway for exposure to FBs, with a comparable contribution to that of dust ingestion. Most of the newly identified FBs are predicted to have persistent, bioaccumulative, or toxic properties. Our work demonstrates that FBs are another class of highly abundant, hazardous, and ubiquitous indoor pollutants that have been overlooked for decades and points to an emerging concern.


Asunto(s)
Contaminación del Aire Interior , Contaminantes Ambientales , Retardadores de Llama , Contaminación del Aire Interior/análisis , China , Polvo/análisis , Exposición a Riesgos Ambientales/análisis , Monitoreo del Ambiente/métodos , Retardadores de Llama/análisis , Humanos
4.
Environ Sci Technol ; 55(18): 12424-12436, 2021 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-34506115

RESUMEN

Our previous study demonstrated massive emissions of liquid crystal monomers (LCMs) from liquid crystal display (LCD)-associated e-waste dismantling; however, the compositions, priority list, and inventory of LCMs in waste LCD panels remain unknown. Herein, we conducted the first comprehensive identification covering a broader range of LCMs, including 21 biphenyls and analogues (BAs), 28 cyanobiphenyls and analogues (CBAs), and 44 fluorinated biphenyls and analogues (FBAs), in waste television/computer LCD panels. A total of 64 of the 93 target LCMs, including 19 BAs, 6 CBAs, and 39 FBAs, were widely detected in collected waste LCD panels. Approximately 10-18 of the 64 detectable LCMs were identified as the main compositions in various waste LCD panels, which contributed to >90% of the total LCMs. Total concentrations of FBAs in the television/computer LCD panel samples were comparable to those of BAs but much higher than those of CBAs, indicating FBAs and BAs being the commonly used LCM categories. The composition distribution of LCMs varied between television/computer LCDs and among different brands of television/computer LCDs. A preliminary estimate of the globally direct release of LCMs from waste television/computer LCD panels into various environmental compartments was about 1.07-107 kg/year, which will increase considerably in the near future.


Asunto(s)
Residuos Electrónicos , Cristales Líquidos , Residuos Electrónicos/análisis
5.
Environ Sci Technol ; 55(9): 5984-5992, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33877816

RESUMEN

Liquid-crystal monomers (LCMs), especially fluorinated biphenyls and analogues (FBAs), are considered to be a new generation of persistent, bioaccumulative, and toxic organic pollutants, but their emissions from liquid-crystal display (LCD)-associated e-waste dismantling remain unknown. To fill this knowledge gap, a broad range of 46 LCMs, including 39 FBAs and 7 biphenyls/bicyclohexyls and analogues (BAs), were investigated by a dedicated target analysis in e-waste dust samples. Of 39 target FBAs, 34 were detected in LCD dismantling-associated dust. Among these 34 detectable FBAs, 9 were detected in 100% of the samples and 25 were frequently detected in >50% of the samples. The total concentrations of these 34 FBAs (∑34FBAs) detected in LCD e-waste dust were in the range of 225-976,000 (median: 18,500) ng/g, significantly higher than those in non-LCD e-waste dust (range: 292-18,500, median: 2300 ng/g). In addition to FBAs, six of seven BAs were also frequently detected in LCD e-waste dust with total concentrations (∑6BAs) of 29.8-269,000 (median: 3470) ng/g. Very strong and significant correlations (P < 0.01) were identified in all frequently detected LCMs, indicating their common applications and similar sources. Our findings demonstrate that e-waste dismantling contributes elevated emissions of FBAs and BAs to the ambient environment.


Asunto(s)
Residuos Electrónicos , Contaminantes Ambientales , Cristales Líquidos , Bifenilos Policlorados , China , Polvo/análisis , Residuos Electrónicos/análisis , Monitoreo del Ambiente , Contaminantes Orgánicos Persistentes
6.
Environ Res ; 185: 109462, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32251911

RESUMEN

Persistent halogenated compounds (PHCs), including dichlorodiphenyltrichloroethane and its metabolites (DDTs), polybrominated diphenyl ethers (PBDEs), alternative brominated flame retardants (ABFRs), and dechlorane plus (DP), were analyzed in muscle of six bird species from the South China Sea. DDTs, with concentrations up to 19,000 ng/g lipid weight (lw), were the dominant contaminants contributing to 66-99% of PHCs in birds. Concentrations of PBDEs, ABFRs, and DP ranged from 1.1 to 130, 0.73-40, and 0.21-2.5 ng/g lw, respectively. Historically pollution of DDTs and flame retardants in surrounding Asian lands were the main sources for PHCs in birds. BDE 209 was the primary PBDE congener in all birds. 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) were the main ABFRs. Anti-DP and p,p'-DDE were the dominating compounds of DP and DDTs, respectively. Only concentrations of BDEs 153, 203, 196, and 207, p,p'-DDE, and p,p'-DDD showed significant and positive correlations with δ15N values in samples. The resident birds, red-footed booby (Sula sula), had much lower levels of p,p'-DDE and most of PBDEs than those in migratory birds from the South China Sea. Results of stable isotope ratios of carbon suggest the highly variable food items for the five migratory bird species. The abundance of DBDPE in red-footed booby might be related with the ingestion of plastic debris, which still warrants further verification.


Asunto(s)
Monitoreo del Ambiente , Retardadores de Llama , Animales , Aves , China , Contaminación Ambiental , Retardadores de Llama/análisis , Éteres Difenilos Halogenados/análisis
7.
Environ Sci Technol ; 53(24): 14700-14708, 2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31633338

RESUMEN

To comprehensively clarify human exposure to halogenated flame retardants (HFRs) and polychlorinated biphenyls (PCBs) through dermal uptake and hand-to-mouth intake, skin wipe samples from four typical skin locations from 30 volunteers were collected. The total concentration of the target chemicals (24 HFRs and 16 PCBs) ranged from 203 to 4470 ng/m2. BDE-209 and DBDPE accounted for about 37 and 40% of ∑24HFRs, respectively, and PCB-41 and PCB-110 were the dominant PCB congeners, with proportion of 24 and 10%, respectively. Although exhibiting relatively lower concentrations of contaminants than bared skin locations, clothing-covered skin areas were also detected with considerable levels of HFRs and PCBs, indicating clothing to be a potentially significant exposure source. Significant differences in HFR and PCB levels and profiles were also observed between males and females, with more lower-volatility chemicals in male-bared skin locations and more higher-volatility compounds in clothing-covered skin locations of female participants. The mean estimated whole-body dermal absorption doses of ∑8HFRs and ∑16PCBs (2.9 × 10-4 and 6.7 × 10-6 mg/kg·d) were 1-2 orders of magnitude higher than ingestion doses via hand-to-mouth contact (6.6 × 10-7 and 3.1 × 10-7 mg/kg·d). The total noncarcinogenic health risk resulted from whole-body dermal absorption and oral ingestion to ∑7HFRs and ∑16PCBs were 5.2 and 0.35, respectively.


Asunto(s)
Contaminantes Ambientales , Retardadores de Llama , Bifenilos Policlorados , Vestuario , Monitoreo del Ambiente , Femenino , Éteres Difenilos Halogenados , Humanos , Masculino , Medición de Riesgo
8.
Ecotoxicol Environ Saf ; 186: 109758, 2019 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-31600649

RESUMEN

Plenty of banned and emerging persistent organic pollutants (POPs), including dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), and decabromodiphenyl ethane (DBDPE), were measured in oriental magpie-robins from an e-waste recycling site, an urban site (Guangzhou City), and a rural site in South China. Median concentrations of DDTs, PCBs, PBDEs, DP, and DBDPE ranged from 1,000-1,313, 800-59,368, 244-5,740, 24.1-127, and 14.7-36.0 ng/g lipid weight, respectively. Birds from the e-waste site had significantly higher concentrations of PCBs and PBDEs than those from urban and rural sites (p < 0.05), implying contamination of PCBs and PBDEs brought by e-waste recycling activities. DDTs were the predominant POPs in birds from urban and rural sites. The values of δ15N were significantly and positively correlated with concentrations of p,p'-DDE and low-halogenated chemicals in samples from the e-waste site (p < 0.05), indicating the trophic magnification of these chemicals in birds. However, concentrations of most POPs were not significantly correlated with the δ15N values in birds from urban and rural sites. PCBs and PBDEs in birds from urban and rural sites were not likely from local sources, and the biomagnification of POPs in different sites needed to be further investigated with caution.


Asunto(s)
Bioacumulación , Residuos Electrónicos/análisis , Monitoreo del Ambiente/métodos , Contaminantes Ambientales/metabolismo , Passeriformes/metabolismo , Animales , China , Éteres Difenilos Halogenados/análisis , Músculos/metabolismo , Bifenilos Policlorados/análisis , Población Rural , Población Urbana
9.
Environ Technol ; 35(1-4): 271-7, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24600865

RESUMEN

Phosphorus (P) in hydrolysed urine can be recovered through struvite formation. In the present study, batch experiments were conducted to investigate the effects of contact to the atmosphere (i.e. open and closed) and dilution [Vurine/(Vurine + Vwater)] (i.e. 100%, 50% and 25%) on P recovery from fresh urine through struvite formation with the addition of magnesium chloride (molar ratios of Mg/P = 1.3 and 2.0) after 32 d of storage. The P loss mainly occurred during the initial stages of precipitation with calcium and magnesium (5 d). The precipitates formed at the bottom of the jars were identified by X-ray diffraction to be struvite, hydroxyapatite and calcite. The results showed that the P recovery efficiency from urine solutions in open jars was lower than that in closed jars. It caused significant ammonia volatilization in open jars, resulting in higher nitrogen loss, lower pH values and lower supersaturation. The P recovery efficiency decreased with dilution, which is related to lower pH and lower supersaturation resulting from water dilution. An increase in the Mg/P ratio from 1.3 to 2.0 enhanced P recovery to some extent in urine solutions with different dilutions. The largest P recovery efficiency was 93.7% and 97.3% at an Mg/P ratio of 1.3 and 2.0 for the 100% urine solutions in closedjars, respectively. Scanning electron microscopy revealed smaller struvite particle sizes at lower dilutions (100% and 50% urine) compared with higher dilutions (25% urine).


Asunto(s)
Precipitación Química , Compuestos de Magnesio/síntesis química , Fosfatos/síntesis química , Fósforo/aislamiento & purificación , Fósforo/orina , Orina/química , Atmósfera , Humanos , Estruvita
10.
J Hazard Mater ; 476: 135169, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-39024769

RESUMEN

Human dermal exposure to chlorinated paraffins (CPs) has not been well documented. Therefore, hand wipes were collected from four occupational populations to analyze short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) in order to estimate dermal uptake and oral ingestion via hand-to-mouth contact. The total CP levels (∑SCCPs and ∑MCCPs) in wipes ranged from 71.4 to 2310 µg/m2 in security guards, 37.6 to 333 µg/m2 in taxi drivers, 20.8 to 559 µg/m2 in office workers, and 20.9 to 932 µg/m2 in undergraduates, respectively. Security guards exhibited the highest levels of ∑SCCPs among four populations (p < 0.01). In undergraduates engaged in outdoor activities, C13 emerged as the most dominant SCCPs homologue group, followed by C12, C11, and C10. The levels of ∑SCCPs and ∑MCCPs in males in light haze pollution were significantly higher than that in heavy haze pollution (p < 0.05). The median estimated dermal absorption dose of SCCPs and MCCPs via hand was 22.2 and 104 ng (kg of bw)-1 day-1, respectively, approximately 1.5 times the oral ingestion [12.3 and 74.4 ng (kg of bw)-1 day-1], suggesting that hand contact is a significant exposure source to humans.

11.
Water Sci Technol ; 68(11): 2434-40, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24334893

RESUMEN

Batch experiments were conducted to examine the influence of various process parameters on phosphorus (P) recovery by struvite formation from urine. The results showed that the Mg/P molar ratio is one of the most important parameters affecting P recovery. The Mg/P molar ratio of 1.3 was found the most reasonable for struvite formation, and the P removal efficiency reached more than 96.6%. An increase in pH of urine solutions from 8.7 to 10.0 did not significantly affect P removal, but the quality of crystal formed at pH 10.0 was poor based on scanning electron microscopy analysis. A longer mixing time positively affected struvite formation, and compared to without mixing, the P removal efficiency increased from 72.7 to 97.3% after 5 min of mixing. The addition of seed material had no influence on the P removal efficiency, but contributed to the formation of struvite clusters.


Asunto(s)
Compuestos de Magnesio/síntesis química , Fosfatos/síntesis química , Fósforo/aislamiento & purificación , Orina/química , Estruvita
12.
Environ Technol ; 44(22): 3382-3392, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35332842

RESUMEN

In order to treat domestic wastewater containing phosphorus and chemical oxygen demand (COD), the new technology of Sinusoidal Alternating Current (AC) Fenton Oxidation-Coagulation (SACFOC) was used to improve the removal efficiency (Re) and reduce energy consumption (EEC). The morphology, elemental composition, crystal structure and functional groups of the sludge were characterised by Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDS), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The results show that total phosphorus removal efficiency {Re(TP)} and removal efficiency of organic matter {Re(COD)} can reach 97.56% and 87.77%, respectively, but EEC is only 0.09 kWh·m-3 under the optimum conditions of pH0 = 3, current density (j) = 0.5 A·m-2, c0(TP) = 18 mg·dm-3, c0(COD) = 300 mg·dm-3, c0(H2O2) = 0.06 mol·dm-3, t = 45 min. As compared with direct current (DC) Fenton Oxidation-Coagulation (DCFOC), the COD removal efficiency of SACFOC treatment was improved by 37%, but the energy consumption was reduced by 45%. The degradation process of total phosphorus and COD by SACFOC abides by the quasi-first-order kinetic model. The process of SACFOC includes double effects of electrocoagulation of iron sol by electrolysis and degrade COD by oxidation of formed hydroxyl radicals (·OH) in wastewater, which improves removal efficiency of total phosphorus and COD in wastewater. Our research findings will provide technical guidance and a theoretical basis for the simultaneous treatment of wastewater containing phosphorus and COD applying SACFOC process.


Asunto(s)
Eliminación de Residuos Líquidos , Aguas Residuales , Eliminación de Residuos Líquidos/métodos , Peróxido de Hidrógeno/química , Fósforo , Análisis de la Demanda Biológica de Oxígeno
13.
Food Chem ; 375: 131663, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-34848092

RESUMEN

This study presented a universal LC-MS/MS method for trace analysis of multiple synthetic phenolic antioxidants (SPAs) in foods by complementary use of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). The analytes included not only the well-known BHT and BHA but also 18 high molecular weight SPAs. The method utilized APCI to achieve sensitive analysis of BHT, Irganox 1010, Irganox 330, and Irganox 3125 based on the finding that APCI significantly improved the sensitivity of these weakly acidic or slightly polar SPAs, and utilized ESI to obtain sensitive analysis of other SPAs. Additionally, the method avoided background contamination by using effective measures including installation of a trapping column in the LC system. Method performance assessment showed satisfactory sensitivity, linearity, accuracy, and precision for analysis of SPAs in vegetable oil, milk powder, and baby fruit puree. Method application revealed widespread contamination of foods with BHT, Irganox 1010, and Irganox 1076.


Asunto(s)
Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en Tándem , Antioxidantes , Presión Atmosférica , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Frutas
14.
Nanoscale ; 14(39): 14322-14340, 2022 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-36106572

RESUMEN

The massive exploitation and use of fossil resources have created many negative issues, such as energy shortage and environmental pollution. It prompts us to turn our attention to the development of new energy technologies. This review summarizes the recent research progress of non-precious transition metal single-atom catalysts (NPT-SACs) for the oxygen reduction reaction (ORR) in Zn-air batteries and fuel cells. Some commonly used preparation methods and their advantages/disadvantages have been summarized. The factors affecting the ORR performances of NPT-SACs have been focused upon, such as the substrate type, coordination environment and nanocluster effects. The loading mass of a metal atom has a direct effect on the ORR performances. Some general strategies for stabilizing metal atoms are included. This review points out some existing challenges of NPT-SACs, and also provides ideas for designing and synthesizing NPT-SACs with excellent ORR performances. The large-scale preparation and commercialization of NPT-SACs with excellent ORR properties are prospected.

15.
Environ Technol ; 43(20): 3161-3174, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33843473

RESUMEN

The effects of initial total phosphorus (TP) concentration, current density, conductivity and initial pH value on the removal rate of TP and energy consumption, as well as the behaviour and mechanism of phosphorus removal, were investigated by sinusoidal alternating current coagulation (SACC). The flocs produced by SACC were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy FTIR and X-ray photo electron spectroscopy. The thermodynamic and kinetic behaviours of phosphorus removal by iron sol adsorption were also studied in detail. In a self-made SACC reactor equipped with five sets of parallel iron electrodes spacing 10 mm, the removal rate of TP reached 90.9% for a pH 7.0 wastewater with 5 mg dm-3 TP (κ = 800 µS cm-1) after being treated for 60 min by applying 2.12 mA cm-2 sinusoidal alternating current. Compared with direct current coagulation (DCC), SACC exhibits a higher removal efficiency of phosphorus due to the stronger adsorption of the produced flocs. It was found that the adsorption in the SACC process follows pseudo-second-order kinetic with the involvement of the intra-particle model. The adsorption of iron sol to phosphorus was an endothermic and spontaneous process, and its adsorption behaviour can be characterized with Langmuir and Redlich-Peterson isothermal adsorption models. SACC may be employed for the treatment of more complex wastewater combined with biological and/or electrochemical techniques.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Adsorción , Concentración de Iones de Hidrógeno , Hierro/química , Cinética , Fósforo , Espectroscopía Infrarroja por Transformada de Fourier , Termodinámica , Aguas Residuales/química , Contaminantes Químicos del Agua/química
16.
J Hazard Mater ; 427: 127909, 2022 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-34863572

RESUMEN

Little is known about the distribution and bioaccumulation of organophosphate esters (OPEs) in mangrove ecosystems. In this study, water, sediments, plants and animals were collected from Qi'ao Island Mangrove Nature Reserve to investigate the levels, bioaccumulation and biomagnification of OPEs. Concentrations of ΣOPEs in the mangrove plant Sonneratia apetala (an exotic species) were greater than those in Kandelia obovata (a native species). Translocation factors of OPEs in the two mangrove tree species were greater than 1, indicating that OPEs were mainly absorbed in aboveground tissues. Concentrations of OPEs in mangrove trees and animals were negatively correlated with their log Kow, suggesting that accumulation of OPEs in mangrove biota was influenced by hydrophobicity. A significant difference for concentrations of ΣOPEs was found among the eight mangrove animal species. Concentrations of ΣOPEs in mangrove animals were related with lipid contents, feeding habits and Kow of OPEs. Biota-sediment accumulation factor of OPEs was larger than 1, suggesting that bioaccumulation of OPEs occurred in mangrove animals. The targeted OPEs except isodecyl diphenyl phosphate were not biomagnified in mangrove animals. This study highlights bioaccumulation of OPEs in mangrove biota and suggests further concern about the ecological risk of OPEs to mangrove biota.


Asunto(s)
Estuarios , Contaminantes Químicos del Agua , Animales , Bioacumulación , China , Ecosistema , Monitoreo del Ambiente , Ésteres , Organofosfatos , Ríos , Contaminantes Químicos del Agua/análisis
17.
Chemosphere ; 280: 130679, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34162078

RESUMEN

Electro-Fenton (EF) coupled with Pulsed alternating current coagulation (PACC) is an effective technology for the treatment of Cu2+-organic wastewater. In this study, the removal efficiency (Re), electrical energy consumption (EEC) and removal mechanism of Cu2+-organic were analyzed and the optimal operation parameters were determined. SEM, EDS, XRD and FTIR were used to characterize the morphology, elemental composition, crystal structure, function groups of sludge produced in the EF-PACC. UV, ESR and GC-MS were employed to determine concentration of organic matter, existence of OH, middle products of decomposed organic matter in EF-PACC, respectively. The results show that under the optimal conditions of initial pH = 2.5, current density (j) = 2 A/m2, initial c(Cu2+) = 50 mg/L, c(chemical oxygen demand, COD) = 500 mg/L, c[H2O2] = 10 mL/L, frequency (f) = 1 Hz, t = 20 min, the Re(Cu2+) can reach 99.59%. Re(COD) is 90.21%, EEC 1.695 × 10-1 kWh/m3, and the amount of produced sludge (Ws) is 0.9283 kg/m3. Compared with single EF and PACC processes, the order of treatment efficiency is EF-PACC > EF > PACC. EF-PACC technique was a highly effective method in the treatment of Cu2+-organic compound wastewater. The EF-PACC coupled process includes that electrolyzed Fe3+ produces electrocoagulation and OH produces degradation of organic compounds. The combined action of the two effects can effectively remove Cu2+-organic from wastewater.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Análisis de la Demanda Biológica de Oxígeno , Peróxido de Hidrógeno , Oxidación-Reducción , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua/análisis
18.
Environ Pollut ; 284: 117208, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-33930779

RESUMEN

Organophosphate esters (OPEs) are ubiquitous contaminants in the environment, whereas their atmospheric processes and fate are poorly understood. The present study revealed the spatial heterogeneity and seasonal variations of traditional and novel OPEs in PM2.5 (particulate matter with diameters < 2.5 µm) across a megacity (including residential areas and potential source sites) in South China. Potential influencing factors on the contamination levels of OPEs were addressed. The total concentrations of 11 traditional OPEs ranging from 262 to 42,194 pg/m3 (median = 1872 pg/m3) were substantially higher than those of 10 novel OPEs (33.5-3835 pg/m3, median = 318 pg/m3). Significant spatial and temporal variations in the concentrations of most OPEs were observed. The overall district-specific contamination levels in this city showed dependence on the secondary industry sector for non-predominant OPEs and on the tertiary industry for predominant OPEs. The seasonal variations of the OPE concentrations suggest difference in their sources or influence of meteorological conditions. The correlations between the individual OPEs in PM2.5 are determined largely by either their applications or physicochemical properties (in particular vapor pressure). The correlations between OPE concentrations and each meteorological factor (temperature, relative humidity, wind speed, and surface solar radiation) were inconsistent (positive and negative). Wind speed had the greatest effect on the OPE levels; While most OPEs bound to PM2.5 were not efficiently scavenged by below-cloud rainfall. The results suggest that atmospheric half-life and Henry's Law Constant of OPEs are also determining factors for the wind speed and rainfall influence, respectively. However, mechanisms underlying the influence of meteorological conditions on atmospheric OPEs still need further research.


Asunto(s)
Retardadores de Llama , China , Ciudades , Monitoreo del Ambiente , Ésteres/análisis , Retardadores de Llama/análisis , Organofosfatos/análisis , Material Particulado/análisis
19.
Sci Total Environ ; 707: 136119, 2020 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-31869616

RESUMEN

Increasing amount of plastic debris stranded on beach can introduce many foreign substances, including organic pollutants into island ecosystems. In the present study, stranded foams were collected from an island located in South China Sea, to investigate the levels and profiles of several flame retardants (FRs) and plasticizers, including polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs), emerging brominated FRs, and dechlorane plus (DP). The concentrations of PBDEs and OPEs in plastic debris ranged from not detected (ND, <0.60 ng/g) to 0.46 mg/g and from ND (<0.70 ng/g) to 17.3 mg/g, respectively. The high levels of PBDEs and OPEs were expected as the fact that PBDEs and OPEs were incorporated additives in plastics. OPEs were the main chemicals in most of foams. Brominated FRs dominated in some samples. Core and surface parts in foams had similar composition profiles of pollutants. Significantly higher concentrations of tris(2-chloroethyl) phosphate (TCEP) and triphenyl phosphate (TPHP) were observed in surface samples than core samples (p < .05). TCEP and TPHP in foam surface seem to be from both incorporated additives and adsorbed chemicals from environmental matrices. The density of pollutants introduced by stranded foams in sampling area was estimated in comparison with air deposition of pollutants. The high loading of pollutants in stranded foams indicates that foams can be potential sources for organic pollutants, especially incorporated plastic additives, in islands.

20.
Environ Pollut ; 266(Pt 2): 115336, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32836048

RESUMEN

Black-spotted frogs and bullfrogs from an e-waste polluted area were collected and examined for legacy and emerging organophosphorus flame retardants (PFRs) and plasticizers. Total concentrations of PFRs and plasticizers were 0.62-15 ng/g wet weight (ww) and 316-4904 ng/g ww in muscles, 2.2-59 ng/g ww and 127-5757 ng/g ww in eggs and gonads, and 1.2-15 ng/g ww and 51-1510 ng/g ww in oviducts, respectively. For muscle tissues, concentrations of ∑PFRs, triethyl phosphate, tris-(2-chloroethyl) phosphate, and tris-(chloro-2-propyl) phosphate were significantly higher in the males than females (p < 0.05). However, for reproductive tissues, eggs exhibited higher levels of those contaminants than gonads (p < 0.05). No significant sex difference in levels of plasticizers was observed in muscles. In contrast, levels for (2-ethylhexyl) phthalate, di-n-butyl phthalate, and di-iso-butyl phthalate in gonads were significantly higher than those in eggs (p < 0.05). Significantly negative linear correlations between maternal transfer ratios and log KOW were found in female frogs. Paternal transfer potentials were first significantly and positively correlated to log KOW (<6) and then decreased afterward in the males. These results indicated that parental transfer was answer for the sex-specific accumulation of PFRs and plasticizers in frogs.


Asunto(s)
Retardadores de Llama/análisis , Animales , Huevos/análisis , Monitoreo del Ambiente , Femenino , Masculino , Organofosfatos , Compuestos Organofosforados , Plastificantes/análisis , Caracteres Sexuales
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