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1.
Chemistry ; 29(18): e202203702, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36656133

RESUMO

Construction of sub-5 nm long-range ordered structures through self-assembly has received increasing attention. Herein, a series of ODMS-based thermotropic liquid crystals (LCs) containing perylene diimide (PDI) were designed and synthesized. These LCs can form ordered nanostructures with periodic sizes around 5 nm including smectic J (SmJ), oblique columnar (Colob ), and hexagonal columnar (Colh ) phases with change in the volume fraction of ODMS, where the layer spacing of the SmJ phase is less than 5 nm. Thin films with parallel oriented nanolines with line width less than 5 nm can be obtained on PDMS-modified silicon substrates by spin-casting and simple thermal annealing processes. Moreover, owing to the strong π-π interaction between PDI cores, these nanolines are long-range ordered with uniaxial orientation in relatively large areas (1.5×1.5 µm2 ) with over 300 continuous microdomains without pre-patterning. These nanostructures provide the possibility of preparing nanotemplates by oxygen plasma etching.

2.
J Hazard Mater ; 435: 129023, 2022 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-35650739

RESUMO

Activation of H2O2 with metal-free catalysts is an efficient and environmentally benign alternative to electron-Fenton (EF) for organics degradation. In the present study, flexible nanocatalysts were synthesized with self-regulated metal oxide nanoparticles (FeOx NPs) for efficient removal of plasticizers from secondary wastewater effluent (SWE). Compared with NGr/EF and FeOx@Gr/EF systems, FeOx@NGr/EF could enhance the decay kinetics of plasticizers by 3.9-4.4 times and reduce 48-59% of the disposal cost. Reactive oxygen species tests and trapping experiments proved that the surface-catalyzed EF effectively broadened the range of solution pH. Density functional theory calculations coupled with electrochemical measurements indicated that the electron transfer rates between Fe-O-C atoms were enhanced with N-doping due to strong interactions between N-Fe bond. The synergistic effects of FeOx and N could improve the oxygen reduction activity for H2O2 generation, and accelerate electron transfer between FeOx/NGr and H2O2 for •OH generation, offering an alternative for wastewater treatment.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Catálise , Peróxido de Hidrogênio/química , Oxirredução , Plastificantes , Poluentes Químicos da Água/química
3.
Soft Matter ; 18(17): 3430-3436, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35437558

RESUMO

The preparation of sub-5-nm ordered structures is very important to the development of today's nanotechnology. Block molecules have the potential to form structures with significantly small characteristic dimensions. Herein two novel organic-inorganic block molecules composed of a hexa-peri-hexabenzocoronene (HBC) core and two oligo(dimethylsiloxane) (ODMS) tails with C2 symmetry are reported. A hierarchical lamello-columnar structure with a two-dimensional rectangular lattice where HBC cores adopt a tilted arrangement was obtained from their bulk self-assembly. The feature sizes are all below 5 nm and can be regulated via the number of ODMS chains. Sub-5-nm line structures were obtained through spin-coating of the block molecules onto silicon substrates modified with poly(dimethylsiloxane). As organic-inorganic hybrid materials, these block molecules may be further applied in sub-5-nm nanopatterning.

4.
Front Microbiol ; 13: 1116975, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36938131

RESUMO

As a well-known pseudo-persistent environmental pollutant, oxybenzone (BP-3) and its related organic ultraviolet (UV) filters have been verified to directly contribute to the increasing mortality rate of coral reefs. Previous studies have revealed the potential role of symbiotic Symbiodiniaceae in protecting corals from the toxic effects of UV filters. However, the detailed protection mechanism(s) have not been explained. Here, the impacts of BP-3 on the symbiotic Symbiodiniaceae Cladocopium goreaui were explored. C. goreaui cells exhibited distinct cell growth at different BP-3 doses, with increasing growth at the lower concentration (2 mg L-1) and rapid death at a higher concentration (20 mg L-1). Furthermore, C. goreaui cells showed a significant BP-3 uptake at the lower BP-3 concentration. BP-3 absorbing cells exhibited elevated photosynthetic efficiency, and decreased cellular carbon and nitrogen contents. Besides, the derivatives of BP-3 and aromatic amino acid metabolism highly responded to BP-3 absorption and biodegradation. Our physiological and metabolic results reveal that the symbiotic Symbiodiniaceae could resist the toxicity of a range of BP-3 through promoting cell division, photosynthesis, and reprogramming amino acid metabolism. This study provides novel insights into the influences of organic UV filters to coral reef ecosystems, which urgently needs increasing attention and management.

5.
Chem Commun (Camb) ; 58(1): 108-111, 2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-34875677

RESUMO

A series of tetraphenylporphyrin-based thermotropic liquid crystals containing oligo(dimethylsiloxane) were synthesized. These disc-coil hybrids form ordered nanostructures with periodic sizes on the sub-5 nm scale, including oblique columnar, lamellar, and hexagonal columnar phases. Films with sub-5 nm line patterns and homeotropically aligned columnar structures can be obtained by substrate-induced self-assembly.

6.
Langmuir ; 2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34342997

RESUMO

Photo-induced alignment of the thin-film morphologies of azobenzene-containing block copolymers (BCPs) is an effective method to obtain a uniaxial pattern of nanocylinders. Although film thickness is an important factor affecting the self-assembly of BCP thin films, the influence of film thickness on the photo-induced alignment of BCP thin-film morphology has never been systematically studied. Herein, we report the thickness-dependent photo-aligned film morphologies of the BCP containing an azobenzene-based liquid crystalline polymer and a poly(ionic liquid) (PIL), with a perfect uniaxial pattern of PIL nanocylinders. For films aligned with the unpolarized light (UPL), the out-of-plane PIL nanocylinders can be obtained in the film with a thickness of only 1L0 (∼30 nm, where L0 is the layer spacing of the hexagonally packed cylinder array), which is far lower than the thickness (more than 4L0) of the thermally annealed film needed to obtain the same morphology. This change is attributed to the orientation effect of UPL on azobenzene mesogens that suppresses the excluded volume effect. For the films aligned with linearly polarized light (LPL), to take advantage of the excluded volume effect to obtain the planar orientation of azobenzene mesogens, the thickness should be controlled to be no more than 3L0 to achieve an in-plane uniaxial alignment of PIL nanocylinders. The above relationship between the morphology and thickness of photo-aligned film eliminates the obstacles encountered in preparing films with well-ordered photo-aligned morphologies.

7.
ACS Appl Mater Interfaces ; 13(30): 36320-36329, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34309364

RESUMO

The zinc-ion battery (ZIB) is a novel energy storage device, an attractive alternative to the lithium-ion battery. The frequently used aqueous electrolyte suffers from many problems such as zinc dendrites and leakage, which prompts hydrogel electrolytes and solid electrolytes as good replacements. However, hydrogel electrolytes are usually unstable, owing to water volatilization. Herein, a novel solid polymer electrolyte (SPE) utilizing coordination of zinc ions is designed and then introduced into an all-solid ZIB. Benefiting from the unique coordination structure between the polymer and zinc ions, the SPE shows outstanding flexibility, high ion conductivity, and self-healing properties. In addition, the imine bonds in the polymer allow the electrolyte to degrade in acid environments, endowing its recyclability. More importantly, solid-state ZIBs based on the polymer electrolytes exhibit an impressive cycling stability (125% capacity retention after 300 cycles) and a high coulombic efficiency (94% after 300 cycles). The results demonstrate the promising potentials of the developed SPEs that can be used in all-solid ZIBs.

8.
Sci Total Environ ; 791: 148107, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118668

RESUMO

Low yields of H2O2 and a narrow range of appropriate pH values have been two major drawbacks for electro-Fenton (EF) process. Herein, metal-free electrochemical advanced oxidation processes (EAOPs) were developed with nitrogen and sulfur co-doped electrochemically exfoliated graphene (N, S-EEGr) electrocatalysts, which was confirmed as an outstanding bifunctional catalyst for synchronous generation and activation of H2O2 via (2 + 1) e- consecutive reduction reactions. Specifically, two elements (N, S) in metal-free N, S-EEGr-CF cathode synergize to promote the formation of H2O2 followed by its activation. With N, S-EEGr-CF cathode, phenol of initial 50 mg L-1 could be effectively removed within pH 3-11 and 6.25 mA cm-2, and 100% removal efficiency could be achieved within 15-min even at neutral pH. The pseudo-first-order rate constant for phenol removal in metal-free EAOPs with N,S-EEGr-CF at neutral pH was 10 times higher than that with EF process. Detection of active species, coupled with decay kinetics with specific trapping agents, confirmed that OH was the dominant oxidizing species promoting removal efficiencies of organics (phenol, antibiotics and dyes) at pH 3 and pH 7. In the actual wastewater treatment, the synergistic effect of bifunctional catalyst would also be used for improving the degradation efficiency of organics. Thus, the metal-free EAOPs with N,S-EEGr-CF cathode may serve as an alternative in wastewater treatment with a broadened range of solution pH values and avoiding Fe2+ (catalyst) addition.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Eletrodos , Peróxido de Hidrogênio , Radical Hidroxila , Oxirredução , Poluentes Químicos da Água/análise
9.
Chemosphere ; 274: 129983, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33979916

RESUMO

A flow-through reactor with integration of electrosorption (ES) and peroxi-coagulation (PC) processes was designed for organics removal. Impacts of key parameters (solution pH, flow rate, initial concentration of organics, applied voltage) on the removal efficiency of Orange II were explored. Under the optimized conditions, 93% removal efficiency and 1043 mg g-1 removal capacity of Orange II could be obtained with an energy consumption of 31.9 kWh m-3 order-1. Controlled experiments of ES for pollutants removal, and the detections of dissolved irons and the generated hydroxyl radicals (•OH) were conducted, demonstrating the coupling effect and contribution ratio of ES and PC for organics removal in this flow-through system. The spatiotemporal efficiency of the integrated flow-through system was more than 10 times of conventional ES system, providing more potential for practical application of wastewater treatment. The flow-through system was also verified to be advantageous for removal of other organic pollutants including 2,4-dichlorophenoxyacetic acid, phenol and methylene blue with high removal efficiencies. This study proved that the integrated flow-through process was an efficient, comparative and applicable method for wastewater treatment.


Assuntos
Herbicidas , Poluentes Químicos da Água , Purificação da Água , Radical Hidroxila , Fenol
10.
Chem Commun (Camb) ; 56(71): 10341-10344, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32760981

RESUMO

Sub-5 nm ordered nanostructures including lamellar, double gyroid, and columnar phases are formed by a series of oligo(dimethylsiloxane) (ODMS)-based rod-coil liquid crystals with accurate molecular weights. Films with well-oriented line patterns can be obtained by substrate-induced directed self-assembly, which may be further used as lithographic templates.

11.
J Hazard Mater ; 393: 122513, 2020 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-32208334

RESUMO

The traditional electro-Fenton (EF) has been facing major challenges including narrow suitable range of pH and non-reusability of catalyst. To overcome these drawbacks we synthesized FeIIFeIII-layered double hydroxide modified carbon felt (FeIIFeIII LDH-CF) cathode via in situ solvo-thermal process. Chemical composition and electrochemical characterization of FeIIFeIII LDH-CF were tested and analyzed. The apparent rate constant of decay kinetics of ofloxacin (OFC) with FeIIFeIII LDH-CF (0.18 min-1) at pH 7 was more than 3 times higher than that of homogeneous EF (0.05 min-1) at pH 3 with 0.1 mM Fe2+ under same current density (9.37 mA cm-2). Also, a series of experiments including evolution of solution pH, iron leaching, OFC removal with trapping agent and quantitative detection of hydroxyl radicals (OH) were conducted, demonstrating the dominant role of OH generated by surface catalyst via ≡ FeII/FeIII on LDH cathode for degradation of organics as well contributing to high efficiency and good stability at neutral pH. Besides, formation and evolution of aromatic intermediates, carboxylic acids and inorganic ions (F-, NH4+ and NO3-) were identified by High-Performance Liquid chromatography, Gas Chromatography-Mass Spectrometry and ionic chromatography analyses. These findings allowed proposing a plausible degradation pathway of OFC by OH generated in the heterogeneous EF process.


Assuntos
Antibacterianos/química , Carbono/química , Hidróxidos/química , Ferro/química , Ofloxacino/química , Poluentes Químicos da Água/química , Eletrodos , Eletrólise , Concentração de Íons de Hidrogênio
12.
Chemosphere ; 241: 125066, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31622888

RESUMO

A porous carbon aerogel (CA) was prepared to activate persulfate (PS) for the removal of phenol. The adsorption of phenol on CA and its removal in CA/PS system was fitted to a second-order model and first-order kinetic model, respectively. Influencing factors of CA/PS such as pH, CA dose, PS concentration, phenol concentration and temperature were investigated. CA/PS presented good performance on phenol removal over a pH range of 3-11 with the highest removal obtained at pH 7. Four kinds of organic pollutants including tetracycline, Rhodamine B, Safranine T and malachite green were investigated in the CA/PS system, proving that the adsorption of the contaminants benefitted their subsequent oxidation removal. The removal of aromatic compounds (phenol, p-diphenol, p-chlorophenol, and p-nitrophenol) in CA/PS system followed a decreasing order of hydroxyl > chlorine > nitro. The radical scavenging experiments suggested the removal of phenol was mainly through a non-radical pathway. The study presented the preparation and application of a green catalyst to activate PS, which is very promising for the development of the technology and the treatment of phenolic wastewater.


Assuntos
Carbono/química , Fenol/química , Poluentes Químicos da Água/química , Adsorção , Catálise , Clorofenóis , Radical Hidroxila/química , Cinética , Nitrofenóis , Oxirredução , Porosidade , Sulfatos/química , Tetraciclina , Águas Residuárias/química , Poluentes Químicos da Água/análise
13.
J Hazard Mater ; 368: 830-839, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30743230

RESUMO

Conventionally the deep treatment and disinfection are fulfilled by different processes for municipal wastewater treatment, this work verified a breakthrough by one process of novel flow-through electro-Fenton (EF) with graphene-modified cathode, which is usually seemed to be ineffective. This process was firstly confirmed to be cost-effective for simultaneous sulfadiazines (SDZs) degradation and disinfection from municipal secondary effluent with a very low electrical energy consumption (EEC) of 0.21 kW h/m3, attributed to the high H2O2 production of 4.41 mg/h/cm2 on the novel graphite felt cathode modified by electrochemically exfoliated graphene (EEGr) with a low EEC of 3.08 kW h/(kg H2O2). Compared with the ineffective SDZs degradation by the conventional flow EF, this process was more cost-effective and overcame the harsh requirements on electrolyte concentration. It also showed good effectiveness in the degradation of different antibiotics, and the graphene-modified cathode still kept stable performance after eight consecutive runs. Account for the combined action of OH and active chlorine, the formation of hydroxylated and chlorine containing by-products was confirmed, and a possible degradation mechanism for SDZs was proposed. This flow-through EF process provided an alternative method for the disinfection and antibiotics degradation by one process for the treatment and reuse of municipal secondary effluent.


Assuntos
Antibacterianos/química , Desinfecção/métodos , Grafite/química , Peróxido de Hidrogênio/química , Ferro/química , Sulfadiazina/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Eletrodos , Águas Residuárias
14.
Chemosphere ; 212: 784-793, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30189405

RESUMO

The chlorinated phenoxy herbicide of 2,4-dichlorophenoxyacetic acid (2,4-D) was oxidized by thermally activated persulfate (TAP). This herbicide was studied for different persulfate dosages (0.97-7.29 g L-1), for varying initial pH levels (3-12) and temperatures (25-70 °C). Compared with Fe2+/PS, TAP could achieve a higher total organic carbon (TOC) removal under wider pH ranges of 3-12. Increasing the mole ratio of PS to 2,4-D favored for the decay of 2,4-D and the best performance was achieved at the ratio of 50. The 2,4-D degradation rate constant highly depended on the initial pH and temperature, in accordance with the Arrhenius model, with an apparent activation energy of 135.24 kJ mol-1. The study of scavenging radicals and the EPR confirmed the presence of both SO4- and OH. However, SO4- was the predominant oxidation radical for 2,4-D decay. The presence of both Cl- and CO32- inhibited the degradation of 2,4-D, whereas the effect of NO3- could be negligible. Verified by GC/MS, HPLC and ion chromatography, a possible degradation mechanism was proposed.


Assuntos
Ácido 2,4-Diclorofenoxiacético/química , Sulfatos/química , Herbicidas/química , Temperatura Alta , Concentração de Íons de Hidrogênio , Oxirredução , Temperatura , Poluentes Químicos da Água/química
15.
Chemosphere ; 206: 439-446, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29758501

RESUMO

H2O2 production plays an important role in electro-Fenton process for pharmaceutical and personal care products (PPCPs) degradation. In this work, carbon nanotube (CNT) was attempted to make a gas diffusion electrode (GDE) by rolling method to achieve a high H2O2 production and current efficiency, and it was further used as electro-Fenton cathode for the degradation of acetylsalicylic acid (ASA) as one kind of PPCPs. The optimal amount of catalyst layer was 0.15 g CNT and 93.75 µL PTFE, obtaining the production of H2O2 of 805 mg L-1 in 0.05 mM Na2SO4 solution at 100 mA after 180 min. The degradation of ASA by electro-Fenton on such a CNT-GDE cathode was studied, and some important parameters such as current, pH as well as the dosage of Fe2+ were optimized. The degradation ratio of ASA could achieve almost 100% after 10 min and the TOC removal ratio was 62% at 1 h under the condition of 100 mA and pH 3, showing a great potential for the treatment of PPCPs.


Assuntos
Aspirina/química , Eletrodos/estatística & dados numéricos , Nanotubos de Carbono/química , Poluentes Químicos da Água/química , Difusão
16.
Bioprocess Biosyst Eng ; 39(3): 511-9, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26747441

RESUMO

This work studied a cost-effective electrosorption that driven by microbial fuel cells (MFC-sorption) to remove Cu(2+) from wastewater without an external energy supply. The impact factors, adsorption isotherms and kinetics of the novel process were investigated. It indicated that a low electrolyte concentration and a high solution pH could enhance the Cu(2+) removal efficiency, while the adsorption capacity increased with the increase of numbers of MFCs in series and the initial Cu(2+) concentration. The adsorption isotherms study indicated that the monolayer adsorption in MFC-sorption was dominant. The kinetics study suggested the increase of initial Cu(2+) concentration could enhance the initial adsorption rate. The electrode characterizations verified the existence of Cu2O and Cu on the electrode surface of active carbon fibers (ACFs), suggesting that MFC-sorption was not only an adsorption process, but also a redox reaction process.


Assuntos
Fontes de Energia Bioelétrica , Cobre/química , Concentração de Íons de Hidrogênio , Cinética
17.
Biotechnol Lett ; 37(12): 2357-64, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26272393

RESUMO

Microbial fuel cells (MFCs) face major hurdles for real-world applications as power generators with the exception of powering small sensor devices. Despite tremendous improvements made in the last two decades, MFCs are still too expensive to build and operate and their power output is still too small. In view of this, in recently years, intensive researches have been carried out to expand the applications into other areas such as acid and alkali production, bioremediation of aquatic sediments, desalination and biosensors. Unlike power applications, MFC sensors have the immediate prospect to be practical. This review covers the latest developments in various proposed biosensor applications using MFCs including monitoring microbial activity, testing biochemical oxygen demand, detection of toxicants and detection of microbial biofilms that cause biocorrosion.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais/métodos , Biotecnologia/métodos
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