1、anions

anions發(fā)音

英：　　美：

anions中文意思翻譯

常用釋義：負離子

n.[化學(xué)]陰離子（anion的復數形式）；[化學(xué)]負離子

anions常用詞組：

anion exchange───陰離子交換

anion exchanger───陰離子交換劑

anions雙語(yǔ)使用場(chǎng)景

1、It 'shows a thousandfold selectivity for fluoride over other common anions.───它對氟離子的選擇性比其它普通陰離子高幾千倍。

2、The air humidity played major role to the air anions of the atmosphere in the Urban Greenery patches.───空氣濕度在對城市空氣負離子的影響過(guò)程中起到了主要作用。

3、Such ions are capable of reacting with soap to form precipitates and with certain anions present in the water to form scale .───這種離子能夠與肥皂反應形成沉淀，而且能與水中的某些陰離子反應形成水垢。

4、For ionic compounds , the state of having exactly the ratio of cations to anions specified by the chemical formula .───在離子化合物中，正、負離子的比例嚴格遵守化學(xué)公式定義的化合價(jià)關(guān)系。

5、Ionosphere is the height of the gas, solar radiation, ionization with a charge of anions and cations, and some form of electronic freedom.───電離層是高空中的氣體，被太陽(yáng)光的紫外線(xiàn)照射，電離成帶電荷的正離子和負離子及部分自由電子形成的。

6、effect of anions could be neglected.───對電流效率的作用可以忽略。

7、Organic anion transporters(OATs)play a critical role in the elimination of numerous endogenous and exogenous organic anions from the body.───有機陰離子轉運子（OAT）在機體清除各種內、外源性有機陰離子的過(guò)程中發(fā)揮極其重要的作用。

8、Ionic liquid is also known as room temperature molten salts, which consists of nitrogen-containing organic cations and inorganic anions.───離子液體又稱(chēng)室溫熔鹽，基本上是由含氮的有機陽(yáng)離子和大的無(wú)機陰離子組成。

9、If all anions in the serum were measured and accounted for, there would be no gap.───如果血漿中所有的陰離子都能被測定并計算，那就不存在這個(gè)間隙。

anions相似詞語(yǔ)短語(yǔ)

1、monatomic anions───單原子陰離子

2、二氧化鈦光催化 英文參考文獻

發(fā)1篇 氮氟摻雜二氧化鈦光催化微囊藻毒素 （如有需要可以幫翻譯一部分 此類(lèi)文章在線(xiàn)翻譯一般不準) 還有部分無(wú)法發(fā)出，把郵箱留下，我發(fā)給你。

題目：

Visible light-activated N-F-codoped TiO2 nanoparticles for the photocatalytic degradation of microcystin-LR in water

正文：

1. Introduction

The development of nanotechnology for the synthesis of

nanomaterials is providing unprecedented opportunities to deal

with emerging environmental problems associated with water

contamination along with worldwide energy-related concerns [1].

Currently, advanced oxidation technologies (AOTs) and nanotechnologies

(AONs) have been extensively investigated for the

destruction of toxic and recalcitrant organic compounds and

inactivation of microorganisms in water and air [2–12]. Titanium

dioxide (TiO2), a well-known semiconductor with photocatalytic

properties, is a widely used AON for water and air remediation [6–

10]. It has proven to be highly effective in the nonselective

degradation of organic contaminants due to high decomposition

and mineralization rates. However, conventional TiO2 requires

ultraviolet (UV) radiation (l < 400 nm) to overcome its wide band

gap energy (3.2 eV for anatase phase) for photocatalytic

activation [4,11]. This is a technological limitation when aiming

at implementation of large scale sustainable technologies with

renewable energy sources such as solar light, since UV radiation

accounts only for 5% of the total solar spectrum compared to the

visible region (45%) [12,13]. Several attempts have been directed

towards the development of modified TiO2 with visible light

response by dye sensitization, metal (Fe, Co, Ag) [14,15] and

nonmental (N, F, C, S) [4,16–23] doping of the catalyst to reduce

TiO2 band gab energy requirements for photocatalytic activation.

In some metal doping approaches, the resulting visible light

photocatalytic activity has some drawbacks including increase in

the carrier-recombination centers (electron–hole pair species

generated after photo-excitation of the catalyst) and low thermal

stability of the modified material [14]. Moreover, metal leaching

and possible toxicity diminish the potential of employing metaldoped

TiO2 for drinking and wastewater treatment applications. A

more successful approach involves nonmetal doping of TiO2.

Nitrogen doping of TiO2 for visible-light driven photocatalysis

revealed band gap narrowing from the mixing of nitrogen 2p

states with oxygen 2p states on the top of the valence band at

substitutional lattice sites in the form of nitride (Ti–N) or

oxynitride (Ti–O–N). A different arrangement is the formation of

oxyanion species at the interstitial lattice sites creating localized

intergap states [24]. Both configurations make it possible to shift

the optical absorption towards visible light, thus, allowing

photocatalytic activity in the visible region [11,22,23]. Fluorine

doping is also effective to induce modifications of the electronic

structure of TiO2 by the creation of surface oxygen vacancies due to

charge compensation between F and Ti4+ but without producing a

significant change in the optical absorption of TiO2 [21]. Moreover,

codoping of TiO2 with nitrogen and fluorine has demonstrated high

photocatalytic activity in the visible region with beneficial effects

induced by both dopants [25–27]. Huang et al. confirmed strong

visible-light absorption and high photocatalytic activity of N-FTiO2

for p-chlorophenol and Rhodamine B degradation under

visible light irradiation [26]. Xie et al. effectively decomposed

methyl orange with visible light-induced N-F-TiO2 photocatalyst

[27]. Both attributed their findings to the synergistic effect of

nitrogen and fluorine doping.

In addition to nonmetal doping, structural properties of TiO2 are

of significant importance to enhance its physicochemical properties

and photocatalytic response. For instance, the use of self-assembly

surfactant-based sol–gel methods has been reported as an effective

approach to tailor-design the structural properties of TiO2 nanoparticles

and films from molecular precursors [6,8–10]. The

hydrocarbon surfactant is used as pore directing agent and to

control the hydrolysis and condensation rates of the titanium

precursor in the sol formulation. This method has the capacity to

yieldtailor-designedTiO2withhighsurface area,highporosity, small

crystal size with narrow pore size distribution and high photocatalytic

activity under UV [8–10] and visible light irradiation [4].

One of the aims of this work is to develop highly efficient N-Fcodoped

TiO2 nanoparticles with enhanced structural properties

and high photocatalytic activity under visible light irradiation

using a novel sol–gel route employing a nonionic fluorosurfactant

as pore directing agent and fluorine dopant and ethylenediamine

as nitrogen source. Fluorosurfactants or fluorinated surfactants,

have been used mainly as antistatic, antifogging and wetting

agents, and paint coating additives [28]. Only recent studies have

focused on the use of fluorinated surfactants as pore template for

mesoporous silica materials [29–32], signifying a great potential

for novel ceramic materials.

The second aim of this work is to focus on the application of

such nanoparticles in engineered water treatment processes for

the destruction of environmental contaminants of worldwide

concern. Drinking water treatment plants are facing more

prevalent occurrence of cyanobacterial harmful algae blooms

(Cyano-HABs) and the release of their toxins in their water sources.

These toxins are considered a serious health risk due to their high

solubility in water, toxicity (i.e., hepatotoxicity, neurotoxicity, and

carcinogenicity) and chemical stability. Among them, microcystin-

LR (MC-LR) is one of the most commonly found cyanotoxins in

Cyano-HABs and the most toxic derivative of the group of

microcystins [33]. Conventional TiO2 has been proven to be

effective in the treatment of MC-LR under UV radiation [34,35].

Recent work demonstrated high degradation rates of MC-LR with

nitrogen-doped TiO2 nanoparticles [4]. In this study, we present

results on the destruction of MC-LR with N-F-TiO2 nanoparticles

under visible light irradiation.

2. Experimental

2.1. Synthesis of visible light-activated TiO2 nanoparticles

To prepare the modified sol–gel solution, a nonionic fluorosurfactant

(Zonyl FS-300 (FS), 50% solids in H2O, RfCH2CH2O(CH2

CH2O)xH; Rf = F(CF2CF2)y where x = 14 and y = 3, Fluka), acting as

both pore directing agent and fluorine source, dissolved in

isopropanol (i-PrOH), was used. Acetic acid (Fisher) was added

to maintain a low pH (6.4). Before adding the titania precursor,

anhydrous ethylenediamine (EDA, Fisher) was added in the

solution as nitrogen source. Then, titanium(IV) isopropoxide (TTIP,

97%, Aldrich) was added dropwise under vigorous stirring and

more acetic acid was added for peptidization. The final sol obtained

was transparent, homogeneous and stable after stirred overnight

at room temperature. Afterwards, the sol was dried at room

temperature for 24 h and then calcined in a multi-segment

programmable furnace (Paragon HT-22-D, Thermcraft) where

the temperature was increased at a ramp rate of 60 8C/h to 100 8C

and maintained for 1 h. Then it was increased up to 400 8C under

the same ramp rate, maintained for 2 h and cooled down naturally

to finally obtain a yellowish powder. The FS:i-PrOH:acetic

acid:EDA:TTIP molar ratio employed in the sol–gel for the

preparation of the denoted Particle 1 was 0.01:0.65:1.0:0.1:0.05.

Specifically, the i-PrOH/EDA molar ratio was 2.85 and 14 for

Particles 2, and 3, respectively. Nitrogen-doped TiO2 (Particle 4)

and fluorine-doped TiO2 (Particle 5) where synthesized without FS

and EDA, respectively, maintaining the same final volume by the

addition of more isopropanol. Reference TiO2 was synthesized

using the same procedure but without the addition of nitrogen and

fluorine sources. The synthesized nanoparticles were compared

with Kronos vlp 7000, a commercially available visible lightactivated

TiO2 photocatalyst (Kronos International Inc., D-51373).

2.2. Characterization of synthesized TiO2

An X-ray diffraction (XRD) analysis was performed with a

Kristalloflex D500 diffractometer (Siemens) using Cu Ka

(l = 1.5406A˚ ) radiation, to study the crystal structure and

crystallinity of the TiO2 nanoparticles. The Brunauer–Emmett–

Teller (BET) surface area, pore volume, porosity, Barret–Joyner–

Halenda (BJH) pore size and distribution (based on nitrogen

adsorption and desorption isotherms) were determined by Tristar

300 (Micromeritics) porosimeter analyzer. The samples were

purged with nitrogen gas for 2 h at 150 8C using Flow prep 060

(Micromeritics). A high resolution-transmission electron microscope

(HR-TEM) with field emission gun at 200 kV was employed

to obtain crystal size and crystal structure at the nanoscale. The

samples in ethanol were dispersed using an ultrasonicator (2510RDH,

Bransonic) for 15 min and fixed on a carbon-coated copper grid

(LC200-Cu, EMS). The particle morphology was characterized by an

environmental scanning electron microscope (ESEM, Philips XL 30

ESEM-FEG) at an accelerating voltage of 30 kV. The point of zero

charge (PZC) was measured using a Zetasizer (Malvern Instruments).

The fine elemental composition and electronic structure

was determined with an X-ray photoelectron spectroscope (XPS,

PerkinElmer Model 5300) with Mg Ka X-rays at a takeoff angle of

458 and vacuum pressure of 108 to 109 Torr. The binding

energies were calibrated with respect to C1s core level peak at

284.6 eV. To investigate the optical band gap of the synthesized

TiO2 nanoparticles, the UV–vis absorption spectra were obtained

with a UV–vis spectrophotometer (Shimadzu 2501 PC) mounted

with an integrating sphere accessory (ISR1200) using BaSO4 as

reference standard.

2.3. Photocatalytic evaluation with microcystin-LR under visible light

The photocatalytic activity of the synthesized TiO2 nanoparticles

was evaluated for the degradation of MC-LR. A borosilicate

vessel (i.d. 4.7 cm) was employed as photocatalytic reactor. An

aqueous solution, previously adjusted at the desired pH with

H2SO4 or NaOH without any buffer, was spiked with an aliquot of

MC-LR standard (Calbiochem Cat #. 475815) to achieve an initial

concentration of 1.0  0.05 mg/L. A solution with TiO2 nanoparticles

was dispersed using an ultrasonicator (2510R-DH, Bransonic) for 24 h

and transferred to the reactor containing MC-LR for a final volume

solution of 10 ml. The reactor was completely sealed and mixed to

minimize mass transfer limitations. Two 15W fluorescent lamps

(Cole-Parmer) mounted with UV block filter (UV420, Opticology) to

eliminate spectral range below 420 nm were employed to irradiate

the reactors. The intensity of the radiation was below the detection

limit when employing an IL 1700 radiometer (International Light)

with a 365 nm sensor. The light intensity was determined using a

broadband radiant power meter (Newport Corporation) for a total

visible light intensity of 7.81  105Wcm2. During irradiation, a fan

was positioned near the reactor to cool it down. Sampling was done at

specific periods of time and the samples were quenched with

methanol to stop any further reaction, filtered (L815, Whatman) to

remove the suspended nanoparticles, transferred to 0.2 ml glass

inserts and placed in sample vials. MC-LR samples were analyzed by

liquid chromatography (LC, Agilent Series 1100) equipped with a

photodiode array detector set at 238 nm under isocratic conditions:

60% (v/v) of 0.05% trifluoroacetic acid (TFA) in MilliQ water and 40%

(v/v) of 0.05% TFA in acetonitrile with a flow rate of 1 ml/min.

The column employed was a C18 Discovery (Supelco) column

(4.6 mm  150 mm, 3 mm particle size) kept at 40 8C with an

injection volume of 50 ml [7]. The handling of the toxin must be

done with extreme care since it is highly toxic and irritant if exposed.

Therefore, all the experiments were conducted in an Advance

Sterilchemgard III Class II biological safety cabinet (Baker Company,

Sanford, ME) with full exhaust.