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1.
Chemosphere ; 263: 128208, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297167

RESUMO

The low concentration of nickel in electroplating wastewater is difficult to treat to meet the discharge standard. In this study, a commercial cation exchange membrane was used to combine the electrodialysis on a titanium plate anode sintered ruthenium-iridium and the electrodeposition on a stainless steel cathode to reduce the nickel concentration to less 0.1 mg L-1. The electrolytic properties of the electrodialysis combined with the electrodeposition were investigated at different cell voltages, electrolysis time, initial electrolyte pH, electrolyte flow rates and initial Ni2+ concentrations. The results indicated that the Ni2+ concentration in the anolyte and the catholyte could be reduced to 0.015 and 0.085 mg L-1, respectively, with the initial Ni2+ concentration of 1.0 mg L-1, which could meet the most strict Ni2+ discharge standard of 0.1 mg L-1. The electrodeposition of Ni2+ on the cathode enhanced the migration of the Ni2+ in the electrolytes, which was beneficial to decrease the energy consumption. Therefore, the combination of electrodialysis and electrodeposition was promising to reduce the low concentration of Ni2+ in the electroplating wastewater.


Assuntos
Galvanoplastia , Águas Residuárias , Eletrólise , Íons , Níquel/análise , Águas Residuárias/análise
2.
J Hazard Mater ; 403: 123582, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32781276

RESUMO

Photocatalytic degradation of typical pharmaceuticals in natural sunlight and in actual water is of great significance. In this study, the oxygen or nitrogen linked heptazine-base polymer (ONLH) was successfully incorporated with TiO2 nanoparticles and formed a TiO2/ONLH nanocomposite which was responded to the natural sunlight. Under natural sunlight, the TiO2/ONLH can effectively degrade ten types of pharmaceuticals. In particular, fluoroquinolone containing N-piperazinyl, and cardiovascular drugs containing long aromatic side chains were easily degraded. The half-life of the best degradation performance of propranolol was less than 5 min. The rate constants of propranolol using the TiO2/ONLH were approximately six- and eight-fold higher than those of pristine TiO2 and ONLH, respectively. Two reactive species (OH and O2-) facilitated the rapid degradation of propranolol, which occurred primarily through the hydroxyl radical addition, ring-opening, and ipso substitution reactions. An acute toxicity test using luminescent bacteria indicated that the toxicity of the propranolol reaction solution gradually decreased with lower total organic carbon (TOC). According to the toxicity evaluation of monomer products, the TiO2/ONLH also reduced the generation of toxic transformation products. The effects of actual water/wastewater have further shown the TiO2/ONLH might be applied for the removal of pharmaceuticals in wastewater.

3.
Water Res ; 183: 116115, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32652347

RESUMO

The ultraviolet/chlorine (UV/Cl2) process is an emerging advanced oxidation technology for micropollutant abatement in water and wastewater treatment. However, the application of the conventional UV/Cl2 process in decentralized systems is limited by the transport and management of liquid chlorine. To overcome this limitation, this study evaluated an electrochemically driven UV/Cl2 (E-UV/Cl2) process for micropollutant abatement under conditions simulating decentralized water treatment. The E-UV/Cl2 process combines UV irradiation with in situ electrochemical Cl2 production from anodic oxidation of chloride (Cl-) in source waters. The results show that with typical Cl- concentrations present in water sources for decentralized systems (30-300 mg/L Cl-), sufficient amounts of chlorine could be quickly electrochemically produced at the anode to enable E-UV/Cl2 process for water treatment. Due to its multiple mechanisms for micropollutant abatement (direct photolysis, direct electrolysis, Cl2-mediated oxidation, as well as hydroxyl radical and reactive chlorine species oxidation), the E-UV/Cl2 process effectively eliminated all micropollutants (trimethoprim, ciprofloxacin, metoprolol, and carbamazepine) spiked in a surface water in 5 min. In contrast, at least one micropollutant with ∼20-80% residual concentrations could still be detected in the water treated by 10 min of UV irradiation, chlorination, electrolysis, and the conventional UV/Cl2 process under similar experimental conditions. The electrical energy per order (EEO) for micropollutant abatement ranged from 0.15 to 1.8 kWh/m3 for the E-UV/Cl2 process, which is generally comparable to that for the conventional UV/Cl2 process (0.14-2.7 kWh/m3). These results suggest that by in-situ generating Cl2 from anodic oxidation of Cl-, the E-UV/Cl2 process can overcome the barrier of the conventional UV/Cl2 process and thus provide a promising technology for micropollutant abatement in decentralized water treatment systems.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cloro , Oxirredução , Raios Ultravioleta , Águas Residuárias/análise
4.
Environ Pollut ; 264: 114753, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32559871

RESUMO

Pharmaceutically active compounds (PhACs) are widely found in the environment due to vast human consumption. Lots of work has been devoted to investigating the occurrence and seasonal variations globally. To fully understand characteristics and cross-year variation of PhACs in Beijing, 35 PhACs were analyzed in 46 sites across Beijing from both urban and suburban areas. Concentrations of target PhACs were ranged from levels of ng L-1 to µg L-1. Metoprolol (524 ng L-1), caffeine (390 ng L-1) and acetaminophen (156 ng L-1) were the three most abundant non-antibiotics with the highest median concentration, and nalidixic acid (135 ng L-1), erythromycin (64 ng L-1) and sulfamethoxazole (77 ng L-1) were the most abundant antibiotics. Urban and suburban areas are distinguished by PhAC composition in cluster analysis due to different wastewater collection rate. The ratio of easily removable compound group and hardly removable group was then proposed to reflect the wastewater collection rate. The compositional comparison of PhACs in WWTPs' effluents and their receiving rivers further illustrates the impact of WWTPs in urban area. Higher proportion of antibiotics (>30%) in suburban area reflected the impact of presence of livestock farms, which should be concerned. Further statistical analyses show an improving trend of wastewater collection rate, and excluding metoprolol, an anti-hypertension medicine, the total concentration of 13 target PhACs was reduced by 72% during 2013-2017.


Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água/análise , Pequim , China , Monitoramento Ambiental , Humanos , Rios , Águas Residuárias , Água
5.
Chemosphere ; 253: 126704, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32464774

RESUMO

A novel fibrous adsorbent (DAVSF-CA) was synthesized via grafting caffeic acid (CA) onto dialdehyde viscose staple fiber (DAVSF), and used to selectively adsorb Au(III) from simulated wastewater. Fourier Transform Infrared (FTIR), X-ray Photoelectron (XPS) and Nuclear Magnetic Resonance (NMR) spectra confirmed that caffeic acid was successfully grafted on DAVSF through condensation reaction. Adsorption experiments revealed that the adsorption of Au(III) on DAVSF-CA was extremely dependent on pH values and temperatures, and the maximum adsorption capacity of 3.71 mmol/g for Au(III) was obtained at pH 3.0 and 333 K according to the Langmuir fitting. High temperature was favorable for Au(III) adsorption because the adsorption of Au(III) on the DAVSF-CA was endothermic. The competitive adsorption demonstrated that DAVSF-CA had a good preference to Au(III) adsorption in the presence of some coexisting pollutants. The adsorption isotherm data of Au(III) were well-described by the Langmuir model, while the kinetic data were fitted well by the Pseudo-second-order equation. The major reaction involving the reduction of Au(III) to Au(0) was identified by XPS and XRD analysis. Namely, Au(III) was first captured on protonated functional groups via electrostatic adsorption, and then reduced to its elemental form and formed the nano-particles on the adsorbent surfaces.


Assuntos
Adsorção , Ácidos Cafeicos/química , Celulose/química , Ouro/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Oxirredução , Temperatura , Poluentes Químicos da Água/química
6.
J Hazard Mater ; 386: 121981, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31896003

RESUMO

Contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) is a worldwide problem. In this study, we for the first time revealed the role of the air-water interface in enhancing the removal of long-chain perfluoroalkyl carboxylic (PFCAs; CnF2n+1COOH, n ≥ 7) and perfluoroalkane sulfonic (PFSAs; CnF2n+1SO3H, n ≥ 6) acids, collectively termed as perfluoroalkyl acids (PFAAs), through combined aeration and adsorption on two kinds of activated carbon (AC). Aeration was shown to enhance the removal of long-chain PFAAs through adsorption at the air-water interface and subsequent adsorption of PFAA-enriched air bubbles to the AC. The removal of selected long-chain PFAAs was increased by 50-115 % with the assistance of aeration, depending on the perfluoroalkyl chain length. Aeration is more effective in enhancing long-chain PFAA removal as air-water interface adsorption increases with PFAA chain length due to higher surface activity. After removing adsorbed air bubbles by centrifugation, up to 80 % of the long-chain PFAAs were able to desorb from the sorbent, confirming the contribution of the air-water interface to the adsorption of PFAAs on AC. Aeration during AC treatment of water could enhance the removal of long-chain PFAAs, and improve the performance of AC during water treatment.

7.
Chemosphere ; 241: 125122, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683433

RESUMO

Resin adsorption is considered as a promising method to recover gold ions from wastewater, but further reduction reaction is required to convert gold ions into particles. In this study, a crosslinked polyethyleneimine resin (CPEIR) was developed via a suspension polymerization of polyethyleneimine (PEI) and ethylene glycol diglycidyl ether (EGDE) for gold recovery. The Au(III) adsorption capacities of CPEIR were significantly impacted by solution pH and initial Au(III) concentrations but unaffected by co-existing metal ions. Compared with commercial anion-exchange resin IRA400, the CPEIR exhibited higher sorption amount and selectivity for Au(III) due to its high density of amine and hydroxyl groups on the surfaces. The adsorption isotherm of Au(III) on CPEIR was well described by the Langmuir equation, and the maximum uptake amount of Au(III) was high up to 943.5 mg/g, much higher than the reported sorbents. The adsorption kinetic data on the CPEIR were fitted well by the Pseudo-second-order equation, and the intraparticle diffusion was found to be the rate-controlling process of Au(III) adsorption. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis confirmed that Au(III) ions were adsorbed on the CPEIR via electrostatic attraction and chelating interaction, and subsequently the partial loaded Au(III) ions were reduced to elemental gold whereas the hydroxyl groups of CPEIR were oxidized to carbonyl groups.


Assuntos
Ouro/isolamento & purificação , Polietilenoimina/química , Águas Residuárias/química , Adsorção , Ouro/química , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia Fotoeletrônica , Resinas Sintéticas/química , Difração de Raios X
8.
J Hazard Mater ; 386: 121662, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31771885

RESUMO

The catalytic performance of Fe3O4/reduced graphene oxide (Fe3O4/rGO) nanocomposite makes it attractive for the removal of emerging pollutants from water, but the combination of its efficient adsorption and degradation of per- and polyfluoroalkyl substances has not been studied. Here we report the optimal granular Fe3O4/rGO with high thermal and acid resistance stability through controlling its self-assembly for the adsorption and degradation of sodium p-perfluorous nonenoxybenzene sulfonate (OBS) from water. The maximum adsorption capacity for OBS was calculated to be 362.4 µmol/g according to Langmuir fitting. Electrostatic, π-π and hydrogen bonding interactions were involved in OBS adsorption, and the quaternary N in Fe3O4/rGO was a key adsorption site. The efficiency of the utilization of free radicals generated in Fenton-like and persulfate (PS) systems increased with the increase of OBS adsorbed onto the Fe3O4/rGO, while the increase of OBS amount adsorbed on Fe3O4/rGO would casue a slow OBS removal in the adsorption-degradation process due to the slow adsorption process. The Fenton-like oxidation was more efficient for OBS removal than PS oxidation. The spent Fe3O4/rGO was able to be reused in the Fenton-like system at least ten times, while the OBS removal in the PS reaction system was reduced to 47.8 % after six reuse cycles.

9.
J Colloid Interface Sci ; 557: 655-663, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31561082

RESUMO

Per- and polyfluoroalkyl substances (PFASs) are widely used and co-exist in various aquatic environments, but their co-removal is not clear. In this study, the competitive adsorption behavior and mechanism of six traditional and emerging PFASs on anion-exchange resin IRA67 in the bisolute and mixed systems were studied. The adsorption equilibrium of the long-chain PFASs was at least 96 h whereas 48 h was required for the short-chain PFASs. When the PFASs were co-removed in the bisolute system, their competition was not obvious at low PFAS concentration of 0.01597 mmol/L due to the relatively adequate adsorption sites. When the concentrations of PFASs were increased to 0.07666 mmol/L, the removal of perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS) decreased by 77.78% and 72.09%, respectively. The competitive experiments showed that the adsorbed short-chain PFASs could be replaced by the long-chain ones, which was closely related to their hydrophobicity, backbone and functional groups. With the increase of solution pH from 3 to 7, the polyamine groups on the resin IRA67 were transferred to the base forms and the effective adsorption sites decreased, resulting in a more obvious competitive replacement behavior. This study suggested that the PFASs with long chain could be more effectively removed from the coexisting PFASs solution by the anion-exchange resins, and the short-chain PFASs in water may be removed when high dosage of anion-exchange resins is applied or the solution pH is decreased.

10.
Int J Biol Macromol ; 139: 352-360, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31376452

RESUMO

Novel chitosan-based adsorbent (CS-DEO-SP) was successfully prepared by cross-linking and amination using diepoxyoctane (DEO) and spermine (SP) sequentially for the enhanced adsorption of Cr(VI) from aqueous solutions. The optimal CS-DEO-SP beads were prepared with 1.5 mg/L of SP for 5 h at 50 °C. The prepared beads exhibited heterogeneous and porous surfaces. The increased surface area (79.6%), pore volume (86.0%), and pore size (31.2%) of the modified adsorbent evidenced the successful modification of chitosan beads. The adsorption kinetics of Cr(VI) ions onto the prepared CS-DEO-SP beads was well fitted by the pseudo-second-order model (R2 > 0.97), and the adsorption isotherms adapted well with the Freundlich model (R2 > 0.96). The experimental data revealed that the adsorption of Cr(VI) ions on the CS-DEO-SP beads was extremely dependent on solution pH, and the maximum adsorption capacity of 358.1 mg/g was achieved at acidic condition (pH 2.0). After the regeneration of spent CS-DEO-SP beads using 1.0 mol/L NaOH, the adsorption capacity of reused adsorbent gradually declined within five consecutive adsorption cycles. Overall, the prepared CS-DEO-SP beads showed excellent stability in acidic solution and Cr(V) adsorption performance and thus can be used as an efficient adsorbent for eliminating Cr(VI) ions from acidic metal-plating wastewater.


Assuntos
Quitosana/química , Cromo/química , Microesferas , Adsorção , Aminação , Concentração de Íons de Hidrogênio , Cinética , Estrutura Molecular , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água , Purificação da Água , Difração de Raios X
11.
Chemosphere ; 236: 124374, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31344619

RESUMO

The degradation of irgarol, a frequently detected algaecide in the aquatic environment, by ozonation was investigated in this study. The second-order rate constants for the reaction of irgarol with ozone (O3) and hydroxyl radical (OH) were determined to be 505 M-1 s-1 and 4.96 × 109 M-1 s-1, respectively. During ozonation, sixteen transformation products (TPs) of irgarol were proposed using an electrospray ionization quadrupole time-of-flight mass spectrometer. Most of the TPs are ozone-refractory compounds and therefore could only be further transformed by oxidation with OH generated from O3 decomposition during ozonation. Toxicity analysis using the ecological structure activity relationship class program indicates that some of the TPs (e.g., irgarol sulfoxide) still exhibit high acute or chronic toxicity to aquatic organisms (fish, daphnia, and algae) as the parent compound. With a typical ozone dose applied in water treatment (2 mg/L, corresponding to a specific ozone dose of 0.8 mg O3/mg dissolved organic carbon), irgarol could be completely abated in a selected surface water by ozonation. However, most of the TPs persisted in the ozonation effluent because of their low ozone reactivity. The results of this study suggest that ozonation with typical ozone doses applied in water treatment may not be able to sufficiently reduce the ecotoxicological effects of irgarol on aquatic organisms. More effective treatment processes such as ozone-based advanced oxidation processes may be required to enhance the removal of toxic TPs of irgarol in water treatment.


Assuntos
Herbicidas/química , Herbicidas/toxicidade , Ozônio/química , Ozônio/toxicidade , Triazinas/química , Purificação da Água/instrumentação , Radical Hidroxila/química , Cinética , Estrutura Molecular , Oxirredução , Triazinas/toxicidade , Águas Residuárias/química
12.
J Hazard Mater ; 380: 120888, 2019 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-31336267

RESUMO

This study evaluated the prediction of emerging contaminant (EC) removal during heterogeneous catalytic ozonation by chemical kinetic models. Six ECs with differing ozone reactivity were spiked in a synthetic water and a groundwater, then treated by conventional ozonation and heterogeneous catalytic ozonation with α- or ß-MnO2 catalysts. Results show that catalysts did not considerably influence the removal of ECs with high and intermediate ozone reactivity (diclofenac, gemfibrozil, and bezafibrate), but enhanced the removal efficiencies of ECs with low ozone reactivity (2,4-dichlorophenoxyacetic acid, clofibric acid, and ibuprofen) to varied extent (˜10-30%). The removal efficiencies of ECs could be reasonably predicted using chemical kinetic models based on the ozone (O3) and hydroxyl radical (OH) rate constants of ECs, pseudo-first-order rate constants observed for EC adsorption on the MnO2 catalysts, and O3 and OH exposures observed for catalytic ozonation. Furthermore, the model reveals that ECs are removed mainly by O3 and/or •OH oxidation during heterogeneous catalytic ozonation, while adsorption of ECs on catalysts contributes negligibly. Therefore, the removal efficiencies of ECs could be satisfactorily predicted using a simplified model based only on the O3 and OH rate constant and the O3 and OH exposures.

13.
J Hazard Mater ; 374: 167-176, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30999140

RESUMO

A novel CuO-CeO2-CoOx nanocatalyst was prepared for heterogeneous Fenton-like reaction to break the Ni2+-chelate into free Ni2+ in electroless nickel plating wastewater, followed by separation of Ni2+ in an insoluble form. The composite nanocatalysts prepared by co-precipitation method were characterized by XRD, TEM, and XPS, et al. Its catalytic activity as Fenton-like reagent was evaluated by the removal efficiency of Ni(II)-citrate after decomplexation and postprecipitation treatment. Subsequently, the effects of operating parameters on the decomplexation efficiency of the nanocatalysts were investigated including calcination temperature of catalysts, H2O2 concentration, catalyst dosage, initial pH and reaction temperature. Under optimized condition, the Ni(II)-citrate complexes (C0 = 1.0 mM) achieved the complete decomplexation (>99.9%) within 60-min reaction using 0.3 g/L of CuO-CeO2-CoOx calcined at 450 °C and 75 mM of H2O2 at pH 3.0 under 50 °C of reaction. Then, Ni2+ after decomplexation could be completely removed by the subsequent precipitation at pH 11.0. In addition, the life test of CuO-CeO2-CoOx catalyst indicated that, after recycled 10 times, its activity for decomplexation of Ni(II)-citrate decreased no more than 8%. As a result, this new heterogeneous Fenton-like process is promising for decomplexation and purification of electroless nickel plating wastewater as a sludge reduction technology.

14.
Chemosphere ; 224: 187-194, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30825849

RESUMO

Adsorption by powder activated carbon (PAC) is recognized as an efficient method for the removal of perfluorinated compounds (PFCs) in water, while the poor separation of spent PAC makes it difficult for further regeneration, increasing the treatment cost significantly. In this study, an ultrafine magnetic activated carbon (MAC) consisting of Fe3O4 and PAC was prepared by ball milling to remove PFCs from water efficiently. Increasing the percentage of Fe3O4 and balling milling time decreased its adsorption capacity for perfluoroctane sulfonate (PFOS), whereas increased the magnetic separation property to some degree. The optimized MAC was prepared with a Fe3O4 to PAC mass ratio of 1:3 after ball milling for 2 h, and the adsorption equilibriums of all the four PFCs on the optimal MAC were reached within less than 2 h, with the adsorption capacities of 1.63, 0.90, 0.33 and 0.21 mmol/g for PFOS, perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS), respectively. Increasing the solution pH hindered the adsorption of PFOS significantly when the pH was less than the zero potential point (around 6) of the MAC, due to the decreased electrostatic attraction. The spent MAC could be easily separated with a magnet and regenerated by a small volume of methanol, and the regenerated MAC could be reused for more than 5 time and remain stable adsorption capacity for PFOS after 3 cycles. This study provides useful insights into the removal of PFCs by separable magnetic PAC in wastewater.


Assuntos
Caprilatos/análise , Carvão Vegetal/química , Fluorcarbonetos/análise , Magnetismo , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção
15.
Environ Sci Technol ; 53(3): 1564-1575, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30604606

RESUMO

This study describes a promising sunlight-driven photocatalyst for the treatment of ofloxacin and other fluoroquinolone antibiotics in water and wastewater. Perylene diimide (PDI) supramolecular nanofibers, which absorb a broad spectrum of sunlight, were prepared via a facile acidification polymerization protocol. Under natural sunlight, the PDI photocatalysts achieved rapid treatment of fluoroquinolone antibiotics, including ciprofloxacin, enrofloxacin, norfloxacin, and ofloxacin. The fastest degradation was observed for ofloxacin, which had a half-life of 2.08 min for the investigated conditions. Various light sources emitting in the UV-vis spectrum were tested, and blue light was found to exhibit the fastest ofloxacin transformation kinetics due to the strong absorption by the PDI catalyst. Reactive species, namely, h+, 1O2, and O2•-, comprised the primary photocatalytic mechanisms for ofloxacin degradation. Frontier electron density calculations and mass spectrometry were used to verify the major degradation pathways of ofloxacin by the PDI-sunlight photocatalytic system and identify the transformation products of ofloxacin, respectively. Degradation mainly occurred through demethylation at the piperazine ring, ketone formation at the morpholine moiety, and aldehyde reaction at the piperazinyl group. An overall mechanism was proposed for ofloxacin degradation in the PDI-sunlight photocatalytic system, and the effects of water quality constituents were examined to determine performance in real water/wastewater systems. Ultimately, the aggregate results from this study highlight the suitability of the PDI-sunlight photocatalytic system to treat antibiotics in real water and wastewater systems.


Assuntos
Nanofibras , Perileno , Ofloxacino , Luz Solar , Águas Residuárias
16.
J Hazard Mater ; 368: 281-291, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30685716

RESUMO

The increasing amounts of pharmaceuticals in aqueous environment are found to be structurally diverse. O3 has been demonstrated as a high effective agent in removing pharmaceuticals, however, O3 is a very selective oxidant which is ineffective for some ozone refractory structures. Recently, a novel electrochemistry-based oxidation process (E-peroxone) has been developed by a simple combination of electrolysis and conventional ozonation process, which can produce a large amount of aqueous OH in situ. E-peroxone process can enhance the performance of conventional ozonation process. The purpose of this study was to investigate the elimination performance of thirty pharmaceuticals with various chemical structures including macrolide, quinolone, sulfonamides, tetracycline, carboxylic group, Naphthalene, Nitrogen-containing group, CC double bond in electrolysis, ozonation and E-peroxone process. Parent pharmaceuticals and TOC elimination were compared. By comparing different chemical groups, the synergy effect of pharmaceuticals with carboxylic and amide groups were significant, with average degradation level 98.7 ± 2.8% within 15 min. Degradation levels of some groups were quite efficient during both ozonation and E-peroxone process, such as macrolide, quinolone, sulfonamides and tetracycline. E-peroxone process improved the TOC and acute toxicity elimination efficiency of mixed pharmaceutical solutions significantly. Major operation parameters and cross correlation analysis were also evaluated.


Assuntos
Eletrólise/métodos , Ozônio/química , Preparações Farmacêuticas/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Modelos Teóricos , Preparações Farmacêuticas/química , Relação Estrutura-Atividade , Poluentes Químicos da Água/química
17.
J Colloid Interface Sci ; 535: 159-168, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30292106

RESUMO

This investigation is based on experimental data to deeply understand the unusual adsorption behavior of the flexible MIL-53s in aqueous solution. In contrast to the strongly flexible MIL-53(Cr) and MIL-53(Al) with large pore form (lp) in water and in their anhydrous state, MIL-53(Fe) exhibits narrow pore form (np) or very narrow pore form (vnp), indicating that breathing effect depends on the nature of the metal. Sulfamethoxazole (SMZ) adsorption results demonstrated that the maximum adsorption capacities predicted by Langmuir model were 1.85, 1.78 and 0.314 mmol/g for MIL-53(Cr), MIL-53(Al), and MIL-53(Fe), respectively. The adsorption equilibrium was rapidly reached within 60 min and the kinetic data best fitted with the pseudo second order model. The lp form of MIL-53(Cr) and MIL-53(Al) in aqueous solution provided the easy entrance for contaminants, lead to lower binding energy and caused modifications of the hydrophobic/hydrophilic character, which all enhanced their adsorption capacities for SMZ. However, the np form of MIL-53(Fe) with small inner pores and hydrophilicity compromised its adsorption capacity for SMZ. The experimental results revealed electrostatic interactions, hydrogen bonding, and π-π interaction/stacking contributed to the adsorption of SMZ on MIL-53s as well. In summary, the complexation of different metal nodes to MOFs is accompanied by the diversity of properties, which significantly affect their adsorptive performance.


Assuntos
Antibacterianos/química , Estruturas Metalorgânicas/química , Sulfonamidas/química , Adsorção , Tamanho da Partícula , Soluções , Propriedades de Superfície , Água/química
18.
ACS Appl Mater Interfaces ; 10(36): 30265-30272, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30114913

RESUMO

A critical challenge in environmental remediation is the design of adsorbents with proper pore size for the removal of organic pollutants. Three covalent organic frameworks (COFs) with different pore sizes were successfully prepared by a room-temperature solution-suspension method and used to remove a typical aryl-organophosphorus flame retardant [triphenyl phosphate (TPhP)] from aqueous solution. The prepared COFs showed strong acid resistance and thermal stability. The 1,3,5-triformylphloroglucinol (TFP) reacted with benzidine (BD) (COF2) and exhibited the highest sorption capacity for TPhP, followed by the reaction of TFP and 4,4″-diamino- p-terphenyl (DT) (COF3), and the reaction of TFP and p-phenylenediamine (COF1). Their adsorption equilibriums were achieved within 12 h, and COFs with a larger pore size have higher initial sorption rate but longer time to reach sorption equilibrium. According to the Langmuir fitting, the maximum sorption capacities of three COFs for TPhP were 86.1, 387.2, and 371.2 mg/g, respectively. The density functional theory calculation verified that COF1 with a small pore size prevents TPhP molecules from entering the pores, resulting in extremely low sorption capacity, whereas a relatively too large pore size (COF3) will decrease the sorption energy, which is also not conducive to the adsorption of TPhP. Moreover, the prepared COFs can selectively adsorb TPhP in the presence of coexisting compounds and had high removal of TPhP from actual municipal wastewater, showing a promising application potential for selective removal of micropollutants from water by precisely controlling the COF structure.

19.
J Hazard Mater ; 359: 104-112, 2018 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-30014905

RESUMO

In this study, we investigated the enantioselective environmental behaviors of the chiral antidepressant venlafaxine (VFX) in lab-scale aquatic ecosystems in the presence of microplastics (MPs). To determine the bioaccumulation, distribution, and metabolism as well as the effects of MPs on aquatic ecosystems, water-sediment, water-Lemna.minor (L.minor), water-Misgurnus.anguillicaudatus (M.anguillicaudatus), and water-sediment-L.minor-M.anguillicaudatus ecosystems were set up and exposed to venlafaxine and two levels of microplastics over a 90-day period. The removal efficiencies of VFX ranged from 58 to 96% in different ecosystems, and VFX degraded significantly faster in the complex water-sediment-L.minor-M.anguillicaudatus ecosystem with S-enantiomer preferentially enriched. The main metabolite O-desmethylvenlafaxine (O-DVFX) was also observed in ecosystems, displaying similar enantioselectivity. When exposed to 50 mg L-1 of microplastics, the amount of venlafaxine in sediment and loach (M.anguillicaudatus) were significantly higher than that in the 1 mg L-1 microplastics treatments, and enhanced accumulation of O-DVFX was observed in loach. The present study for the first time assessed the combined effects of venlafaxine and microplastics in simulated aquatic microcosms, which could help gain an insight into the potential ecological impacts of chiral pollutants and microplastic, and evaluate their environment risks more accurately in future.


Assuntos
Antidepressivos/metabolismo , Araceae/efeitos dos fármacos , Cipriniformes/metabolismo , Cloridrato de Venlafaxina/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Araceae/metabolismo , Biotransformação , Ecossistema , Plásticos
20.
J Hazard Mater ; 359: 248-257, 2018 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-30036755

RESUMO

Recently metal-organic frameworks (MOFs) have attracted great attention in the field of environmental remediation. In this article, rigid MIL-101(Cr) and flexible MIL-53(Cr) were synthesized and used for the adsorption of two typical pharmaceuticals, clofibric acid (CA) and carbamazepine (CBZ), from water. The adsorption equilibrium was rapidly reached within 60 min and the kinetics best fitted with the pseudo-second-order kinetic model. There was no significant difference in the maximum adsorption capacity of CA on MIL-101(Cr) and MIL-53(Cr), and electrostatic interaction was suggested to be the main factor in the adsorption processes. However, for the removal of CBZ, MIL-53(Cr) showed much better adsorptive performance (0.428 mmol/g) than MIL-101(Cr) (0.0570 mmol/g), indicating the adsorption of CBZ on MOFs is affected by the structural property. The Powder X-ray diffraction analysis revealed that MIL-53(Cr) was transformed into large pore form, leading to variations in cell volume up to 33%, lower binding energy and crucial modifications of the hydrophobicity/hydrophilicity. This unusual behavior enhanced its adsorption capacity for CBZ. Moreover, hydrogen bonding and π-π interactions/stacking also contributed to the adsorption of pharmaceuticals on the MOFs. The excellent adsorptive performance of MIL-53(Cr) and its structure/property switching might lead to the applications in water treatment.


Assuntos
Carbamazepina/química , Cromo/química , Ácido Clofíbrico/química , Estruturas Metalorgânicas/química , Poluentes Químicos da Água/química , Adsorção , Cinética , Eletricidade Estática , Purificação da Água/métodos
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