Preparation of Novel NanoSubmicrofiber Catalyst

Preparation of Novel Nano/Submicrofiber Catalyst Containing Nano-TiO 2Particles

Taiqi Liu,Dan Lv,Binbin Cao,Hongtao Wang

Research Center of Ecomaterial,Beijing Institute of Petrochemical Technology,Beijing 102617,People’s Republic of China

Received 21December 2010;accepted 31August 2011DOI 10.1002/app.35577

Published online in Wiley Online Library (https://www.wendangku.net/doc/e012415287.html,).ABSTRACT:A novel Nano/submicrofiber catalyst was prepared via electrospinning technology from poly (vinyl pyrrolidone)(PVP)and nano-TiO 2.First,nano-TiO 2particles were added into the mixture of ethanol and deionized water,the mass ratio of ethanol and deionized water was 1:1,the TiO 2suspension was obtained after 1h with ultrasonic treat-ment and centrifugal effect,Then PVP was added into the above-mentioned suspension and the content of PVP in the sol was 28%.The TiO 2/PVP solution was electrospun with different voltage.The effects of the content of TiO 2and elec-trospinning voltage on diameter of nano/submicrofiber were studied.The nano/submicrofiber catalyst was charac-terized by scanning electron microscopy,transmission elec-tron microcopy,X-ray diffraction,and Fourier transform infrared.The results show that the diameter of nano/submi-crofiber increases with an increase of the content of nano-TiO 2and decreases with the increase of electrospinning volt-age.The analytical result showed that the nano-TiO 2par-ticles were well dispersed in the matrix of PVP,moreover,the crystal type of nano-TiO 2was a mixture of anatase and rutile and the diameter of nano-TiO 2particles in the nano/submicrofiber is in the range of 20–60nm and the nano-TiO 2particle was monodisperse,and the nano-TiO 2particle and PVP molecule was connected by a hydrogen bonding.This nano/submicrofiber catalyst has a high efficiency on degra-dation on CH 2O.56.8percent of CH 2O was degraded under ultraviolet radiation in 80min when the content of nano-TiO 2is 20%in nano/submicrofibers.V

C Key words:nano-TiO 2;PVP;nano/submicrofiber catalyst;

electrospinning;photocatalysis

INTRODUCTION

In recent years,photocatalytic degradable material has attracted increasing attention as a promising method for the removal of toxic organic contami-nants from water and air,and the photocatalytic degradable material has broad applications,how-ever,many problems,such as how to immobilize nano-TiO 2on appropriate carrier to be used repeat-edly and how to improve nano-TiO 2utilization ratio are still left.For improving nano-TiO 2utilization ra-tio,scientist tried to solve the problems by making more surface of nano-TiO 2outside.1,2Commonly sol-gel method is used to immobilize nano-TiO 2,on other hand,immobilization of nano-TiO 2on glass,3metal,4nano-TiO 2thin film,and nano-TiO 2fiber are also tried by Sol–Gel method.For example,with a use of this method,a nano-TiO 2thin film was pre-pared by Yu et al.,5and Zhang et al.,6Li et al.prepared nano-TiO 2fiber,7Madhugiri et al.prepared mesoporous nano-TiO 2fiber.8Although nanometer thin film and nanometer fiber has a high specific surface area,immobilization process needs heat

treatment at a high temperature and limits its

application.

A process which does not need a high tempera-ture for treatment can be available if nano-TiO 2can be immobilized on carrier directly,and in the wide choices of carrier,polymer can be used as a good carrier of nano-TiO 2.Dhannanjeyan et al.immobi-lized nano-TiO 2on modified polyethylene film,9Naskar et al.immobilized nano-TiO 2on foam poly-ethylene film by hot-press method for degradation of organic dyes in aqueous solution.10Above-men-tioned approaches do not need annealing at high temperatures,however,nano-TiO 2exposed outside is still limited.

Electrospinning can prepare nano/submicrofiber,and the diameter of electrospun fibers is 1–2orders of magnitude lower than the diameter of tradition spinning fiber,and the electrospinning fibers have very high specific surface area.11,12Taking water and alcohol (mass ratio 1:1)as solvent,Yang et al.pre-pared poly (vinyl pyrrolidone)(PVP)(M w ?1,300,000)nanofibers is about 20nm in diameter.13Adding nanometer catalyst particles into the poly-mer,many nanometer catalyst particles are unmasked and situated on the surface of the electro-spinning fiber.In this article,TiO 2/PVP nano/sub-microfiber catalyst can be prepared by directly adding nano-TiO 2particles into PVP solution via

V

C 2012Wiley Periodicals,Journal of Applied Polymer Science,Vol.000,000–000(2012)Correspondence to:T.Liu (liutaiqi@https://www.wendangku.net/doc/e012415287.html,).

2012Wiley Periodicals,Inc.2

Inc.J Appl Polym Sci 000:000–000,201

electrospinning technique.This article studied the dispersivity of nano-TiO 2into polymer matrix,for-mation of nanofibrous catalyst via electrospun tech-nique.Photocatalysis performance of the TiO 2/PVP nano/submicrofiber catalyst was also studied.

EXPERIMENTAL

Preparation of nano-TiO 2/PVP suspension system In our experiment,the certain quantity of nano-TiO 2with a particles in the diameter from 20to 60nm,was mixed together with solvents of ethanol and water (w/w ?1:1).The lower layer precipitate was removed and the upper layer suspension was dried after a treatment with ultrasonic for 1h.The maxi-mum concentration of nano-TiO 2suspension is 5.6wt %,then the PVP (K30)was added into the diluted upper layer suspension.The nano-TiO 2/PVP suspension system (28%weight of PVP)can be pre-pared by an ultrasonic treatment for 30min.Preparation of nano/submicrofibers

The basic experimental setup used is shown in Figure 1.The above-mentioned nana-TiO 2/PVP sus-pension system was electrospun at 10,15,20,25,and 30kV with a tip-to-collector distance of 20cm.The PVP nano/submicrofiber and TiO 2/PVP nano/submicrofiber with different content of nano-TiO 2were prepared.The PVP solution (the concentration of PVP in alcohol-water mixed solvents is 28wt %)was used as the blank control.

Characterization of nano/submicrofibers

The structure of nano/submicrofibers was character-ized by Fourier transform infrared (FTIR).Infrared spectrum was obtained by KBr method.The phase structure analyses had been performed by using an X-ray diffractometer.Through images of field emis-sion scanning electron microscope (SEM),we

obtained the surface morphology of fiber and the diameter of fibers.Because of the ununiformity of the diameter of nano/submicrofibers,the average diameters of 50-fibers were used as measurement value of the diameter of fiber.The dispersion of nano-TiO 2in fibers was obtained by transmission electron microscopy (TEM).Photocatalysis experiment of the nano/submicrofiber catalyst

Photocatalysis experiment was conducted in self-making glass tube reactor with a power of 15W of the ultraviolet lamp which is parallel with and above the glass tube.The strength of UV is 385l W/cm 2when operating ultraviolet lamp.The nano/sub-microfibers were electrospun on glass fibers the area of which is 3.8?19cm 2.First,the samples were get into the reactor before the experiment,and the reac-tor was exposed to air and formaldehyde,the rates of which were controlled by gas flow controller.Stopping ventilating after 15min,then we got 1mL gas sample from one side of the reactor using sy-ringe.We got gas sample five times.The ultraviolet lamp was turned on when there was no significant difference in the concentration of formaldehyde which was detected by gas chromatography,and then the experiment began.The concentration of formaldehyde was detected every 4min.

RESULTS AND DISCUSSION

Discussion on the electrospinning with suspension system of nano-TiO 2/PVP

Some properties of solution (such as viscosity,con-ductivity,surface tension),fluid pressure,electro-spinning voltage,deposition distance,and tempera-ture have effect on the diameter of electrospinning fiber.14The effects of the content of nano-TiO 2and electrospinning voltage on the diameter of fiber were mainly investigated.A series of suspension were electrospun with the concentration of PVP sus-pension of 28wt %and nano-TiO 2at different con-tents.Figure 2shows the relationship of the diame-ter of fibers and the content of nano-TiO 2.The diameter of fibers increase with an increase of the content of nano-TiO 2.In the suspension system of TiO 2/PVP in ethanol and water,PVP molecular adsorb at the surface of TiO 2,and PVP molecular and nano-TiO 2particle tangle together via interac-tion.Tangled PVP molecular increases with an increase of the content of nano-TiO 2,and PVP mo-lecular motion was hindered,and the diameter of fiber increases.Figure 3shows the relationship of electrospinning voltage and diameter of fiber when fixing the content of TiO 2and PVP.The diameter

of

Figure 1Schematic representation of electrospinning.

2LIU ET AL.

Journal of Applied Polymer Science DOI 10.1002/app

fiber decreases with an increase of electrospinning voltage,this is because jet of polymer solution has more surface charge density and thus have lager electrostatic repulsive force.Higher electric field in-tensity makes the jet acquiring larger acceleration simultaneously.The two factors could all cause jet,and make fibers acquiring stronger tensile stress

which cause higher tensile strain rate,and thus facil-itate preparing ultrafine fiber.15The analysis of SEM

Figure 4shows SEM images of fiber electrospinning from PVP solution or suspension.Figure 4(a)is

SEM

Figure 3The relationship between nano/diameter of submicrofiber and electrospinning

voltage.

Figure 2The relationship between diameter of nano/submicrofibers and the content of TiO 2

.

Figure 4(a)and (b)SEM images of nano/submicrofibers of PVP (c)and (d)SEM images of nano/submicrofibers of TiO 2/PVP.

NANO/SUBMICROFIBER CATALYST 3

Journal of Applied Polymer Science DOI 10.1002/app

image of PVP nano/submicrofiber,and Figure4(b) is a local enlarged drawing of white block in Figure 4(a).It was noticed that PVP nano/submicrofiber had a uniform smooth surface,but the diameter of fiber was non-uniform extremely,and it was in the range of80–1000nm;Figure4(c)shows SEM image of TiO2/PVP nano/submicrofiber,and Figure4(d)is a local enlarged drawing of white block in Figure 4(c).It can be observed that fibers surface is rough with gibbosity which is possible as a result of nano-TiO2particles in PVP matrix.

The analysis of TEM

Figure5(a)shows TEM image of TiO2/PVP suspen-sion system.It can be observed that nano-TiO2par-ticulates which are in the range of20–60nm and are almost monodisperse are almost homogeneously dis-tributed in PVP matrix.Figure5(b)shows TEM image of TiO2/PVP nano/submicrofiber which is electrospun from TiO2/PVP suspension on the cop-per net and is the finest fiber we select under TEM. It was noticed that nano-TiO2was dispersed in TiO2/PVP nano/submicrofiber the diameter of which is about30nm.It can be also observed that fibers surface has https://www.wendangku.net/doc/e012415287.html,bination of the gibbosity we saw in the TEM image,we can deter-mine that the gibbosity of fibers surface is nano-TiO2 particle.

The analysis of FTIR spectroscopy

Figure6shows FTIR spectra of PVP nano/submicro-fiber and TiO2/PVP nano/submicrofiber before and after high temperature treatment.Except hydroxyl group absorption peak,the others did not change a lot.Figure6(a)shows FTIR spectra of TiO2/PVP nano/submicrofiber with TiO2content20%after high temperature treatment at200 C for1h.Figure 6(b)shows FTIR spectra of TiO2/PVP nano/submi-crofiber with TiO2content20%.Figure6(c)shows FTIR spectra of PVP nano/submicrofiber.It was dis-covered that the3433.1cmà1is the stretch vibration absorption peak of hydroxyl groups,as shown in Figure6(c).Addition of TiO2,the absorption peak of hydroxyl groups of composite fiber is at3415.7 cmà1,and the absorption peak shifted17.4cmà1to lower waves,while its width increases.This is because of the formation of hydrogen bands between TiO2and PVP.15The absorption peak of hydroxyl groups of high temperature treated TiO2/PVP nano/submicrofiber is at3427.3cmà1in Figure6(c). This is because of breakage of hydrogen bands after high temperature treatment.16,17

The analysis of XRD

Figure7(a)shows a X-ray diffraction(XRD)pattern of nano-TiO2powders.The result shows that there are two crystal types of anatase and rutile;Figure 7(b)shows a XRD pattern of TiO2/PVP nano/https://www.wendangku.net/doc/e012415287.html,pared with Figure7(a),the base line of Figure7(b)was higher obviously which was caused by PVP of composite fiber,but the station of diffrac-tion peak remained invariable,so the crystal type of nano-TiO2was a mixture of anatase and rutile. Nano-TiO2we used in our experiment was a mix-ture of anatase and rutile.Rutile and anatase

were Figure5(a)TEM image of TiO2/PVP suspension(b)TEM image of TiO2/PVP

nano/submicrofiber.

Figure6IR spectra of different nano/submicrofibers(a)

TiO2/PVP nano/submicrofibers after high temperature

treatment(b)TiO2/PVP nano/submicrofibers without

high temperature treatment(c)PVP nano/submicrofibers. 4LIU ET AL. Journal of Applied Polymer Science DOI10.1002/app

still found in the TiO 2/PVP nano/submicrofiber after dispersion and electrospinning.Accordingly,nano/submicrofiber catalyst can be prepare using whether rutile TiO 2or anatase TiO 2in the experiment.

Testing of photocatalysis performance

TiO 2/PVP nano/submicrofiber with TiO 2content 20%and 10%and PVP nano/submicrofiber with no nano-TiO 2were tested in our test experiment of pho-tocatalysis performance.The curves of the concentra-tion of formaldehyde-time had been drawn in Figure 8.When the content of TiO 2was 20%in nano/sub-microfibers,the concentration of formaldehyde declined from 1653to 714ppm after light exposure for 80min,and 56.8percent of CH 2O was degraded.When the content of TiO 2was 10%in nano/submi-crofibers,the concentration of formaldehyde declined from 1515to 802ppm,and only 47percent of CH 2O was degraded.The reason was that only TiO 2exposed to fiber surface can play a role in

https://www.wendangku.net/doc/e012415287.html,pared with nano/submicrofiber with TiO 2content 10%,nano/submicrofiber with TiO 2content 20%had more TiO 2exposed to fiber surface and had greater efficiency of photocatalysis degradation for formaldehyde.Testing photocataly-sis performance of TiO 2/PVP nano/submicrofiber,the concentration of formaldehyde increased at first and then decreased after UV light irradiation.The reason was that the specific surface area of nano/submicrofiber was large,and a little formaldehyde gas was adsorbed on the surface of nano/submicro-fiber when the gas was injected into the reactor,then temperature of reactor increased and desorp-tion of formaldehyde on the surface of nano/submi-crofiber made the concentration of formaldehyde increasing under UV light irradiation.Testing photo-catalysis performance of PVP nano/submicrofiber,the concentration of formaldehyde was increasing from 989to 2090ppm.So the adsorption quantity of fiber for formaldehyde was greater.Degradation rate of formaldehyde is much larger than 56.8%consider-ing desorption of formaldehyde in our experiment.The maximum concentration of distributed nano-TiO 2suspension was 5.6wt %,and the electrospin-ning was comparatively easy from concentration of PVP 28%,so the maximum content of TiO 2was 20%in electrospun fiber.For further improving the effi-ciency of nano/submicrofiber catalyst,experiment technology must be improved for the smaller diame-ter of fiber.

CONCLUSIONS

TiO 2/PVP nano/submicrofiber catalyst was pre-pared by electrospinning.The diameter of nano/submicrofiber increased with adding nano-TiO 2or decreasing voltage.Nano-TiO 2particle and PVP molecule was connected by a hydrogen bonding and the crystal type of nano-TiO 2did not change in TiO 2/PVP nano/submicrofiber.The TEM

result

Figure 7XRD patterns of nano-TiO 2and TiO 2/PVP nanocomposite

fiber.

Figure 8Effect of the time under ultraviolet on the con-centration of CH 2O.

NANO/SUBMICROFIBER CATALYST 5

Journal of Applied Polymer Science DOI 10.1002/app

showed that the nano-TiO2particles the diameter of which was in the range of20–60nm were well dis-persed in the matrix of PVP;testing of photocataly-sis performance indicated that nano/submicrofiber catalyst had good photocatalysis performance. Nano/submicrofiber catalyst with photocatalysis ac-tivity had been prepared successfully.Nano/submi-crofiber photocatalysis catalyst with visible light photocatalysis activity is underway.

References

1.Lu,C.;Yang,P.;Du,Y.K.;Hua,N.P.;Song,H.Y.Chin

J Catal2003,24,248.

2.Cai,N.C.;Wang,Y.P.;Cao,Y.L.Chin J Catal1999,20,177.

3.Chen,S.F.;Cao,G.Y.J Environ Sci2003,15,83.

4.Zhang,L.;Zhu,Y.F.;He,Y.Appl Catal B Environ2003,40,

287.

5.Yu,G.;Chen,Z.Y.;Zhang,Z.L.Catal Today2004,90,305.

6.Zhang,P.Y.;Jiang,Z.P.Catal Today2004,90,305.

7.Li,D.;Xia,Y.Nano Lett2003,3,555.

8.Madhugiri,S.;Sun,B.;Smirniotis,P.G.Microporous Mesopo-

rous Mater2004,69,77.

9.Dhananjeyan,M.R.;Mielczarski,E.;Thampi,K.R.;Buffat,P.;

Bensimon,M.;Kulik,A.;Mielczarski,J.;Kiwi,J.J Phys Chem B2001,105,12046.

10.Naskar,S.;Pillay,S.A.;Chanda,M.J Photochem Photobiol A

Chem1998,113,257.

11.Yang,Q.B.;Li,Z.Y.;Hong,Y.L.;Zhao,Y.Y.;Qiu,S.L.;

Wang,C.;Wei,Y.Y.Polym Sci Part B:Polym Phys2004,42, 3721.

12.Liu,T.Q.Nanotechnique for Air Purification;Chemical Indus-

try Press:Beijing2004.

13.Zhang,S.M.;Liu,T.Q.Polym Mater Sci Eng2005,21,292.

14.Reneker,D.H.;Doshi,J.J Electrostat1995,35,151.

15.Sato,T.;Sato,A.;Arai,T.Colloid Surf A:Physicochem Eng

Aspects1998,142,117.

16.Wu,D.C.;Du,Z.L.;Gao,X.S.Nanofiber;Chemical Industry

Press:Beijing,2003,p60.

17.He,X.X.;Sun,D.Q.;Wang,Z.M.Practical Infrared Spectros-

copy,2nd ed.;Petroleum Industry Press;Beijing,1990;Vol.10, p335.

6LIU ET AL. Journal of Applied Polymer Science DOI10.1002/app

雅思口语素材汇总之端午节

雅思口语素材汇总之端午节 雅思口语素材:Dragon Boat Festival(端午节) Qu Yuan The Dragon Boat Festival, also called the Duanwu Festival, is celebrated on the fifth day of the fifth month according to the Chinese calendar. For thousands of years, the festival has been marked by eating zong zi (glutinous rice(糯米)wrapped to form a pyramid using bamboo or reed leaves) and racing dragon boats. The festival is best known for its dragon-boat races, especially in the southern provinces where there are many rivers and lakes. This regatta(赛舟会)commemorates the death of Qu Yuan , an honest minister who is said to have committed suicide by drowning himself in a river. Qu was a minister of the State of Chu situated in present-day Hunan and Hubei provinces, during the Warring States Period (475-221BC)(战国时期). He was upright, loyal and highly esteemed for his wise counsel that brought peace and prosperity to the state. However, when a dishonest and corrupt prince vilified Qu, he was disgraced and dismissed from office. Realizing that the country was now in the hands of evil and corrupt officials, Qu grabbed a large stone and leapt into the Miluo River on the fifth day of the fifth month. Nearby fishermen rushed over to try and save him but were unable to even recover his body. Thereafter, the state declined and was eventually conquered by the State of Qin. The people of Chu who mourned the death of Qu threw rice into the river to feed his ghost every year on the fifth day of the fifth month. But one year, the spirit of Qu appeared and told the mourners that a huge reptile(爬行动物)in the river had stolen the rice. The spirit then advised them to wrap the rice in silk and bind it with five different-colored threads before tossing it into the river. During the Duanwu Festival, a glutinous rice pudding called zong zi is eaten to symbolize the rice offerings to Qu. Ingredients such as beans, lotus seeds(莲子), chestnuts(栗子), pork fat and the golden yolk of a salted duck egg are often

雅思口语常用背诵素材

口语常用背诵素材 一，喜好和厌恶： 1.（释放压力）I guess most young people enjoy listening to music. It’s a perfect way to reduce stress/relieve stress. (*It’s a perfect stress-buster.) 2.（休闲）I think the best way to relax and kill time (kick back and relax) is to be with friends. Chatting with them helps me unwind/wind down (* Chatting with them is very therapeutic). 3.（放松）I found it pretty relaxing to flick through a magazine before going to bed (*before hitting the sack/hitting the hay). 4.（运动）Jogging on sunny days and simply basking in the sun(bathing in the sun) is super enjoyable(pleasurable). /Jogging is my favorite workout. It can always cheer me up after I’ve been down and depressed. And it can help me shed some unwanted weight. 5.（喜欢，提升心情）I’m quite into watching sitcom (I’m fascinated by, I’m crazy about, I adore, I’m very fond of...). Spending 20 minutes in front of the screen and having a good laugh after dinner really puts me in a better mood/ switch my mood/ lift my spirits. 6.（天气）I fancy spring most compared to the other three. Summer is simply too hot and stuffy (*muggy), and you can’t stay out for two minutes without getting sweaty and smelly. Autumn is too dry and winter too freezing cold. 7.（电影）I’m a movie buff (Movies are my biggest pastime), and I would either catch one on my couch or go to the movie theatre when they have the one I like on the big screen./ It's a great form of relaxation for me to while away the hours of a long flight, to keep my family together on the sofa, and to give me a bit of a thrill. 8.（无聊困难）I’m terrible at what I study now./(History is never my forte/ my strong suit). The classes are kind of a drag (It’s super dull/ *It’s mind-numbing), and there’s always loads of (tons of) homework to do. Memorizing those facts and years is a lot of effort (is tricky; is no picnic; is challenging for me). 9.（不能忍）I can’t stand (I hate, I totally dislike) the busy traffic in my city. I’m sick and tired of always getting stuck in traffic for a long time during rush hours. It really bothers me (It drives me crazy, *It drives me up the wall). 10. （受欢迎）Hip-hop is really trendy (is catching on, is all the rage) among young people these days. 二，时间和地点 11. （优点）What’s great about my home town is that there are plenty of shopping malls, coz I’m a shopaholic and I can shop for hours. 12. （远）The stadium is quite far away from where I live, and every time I want to do there, it takes me roughly 40 minutes by bus to arrive. (It’s one-hour drive from the city center.) 13. （方便）My apartment is in the center/heart of the city, a handy location where I can find supermarkets and clubs right on my doorstep. It’s a bit noisy though. 14. （近）I’m a movie-goer and and there’s a movie theater pretty close to my home, so I go there quite often (frequently). (close to my home= *within walking distance of my home , *in close proximity to my home) 15. （经常）I have a heavy workload at school, so I have to go to the library to study pretty much

雅思口语素材

雅思口语素材 Document serial number【LGGKGB-LGG98YT-LGGT8CB-LGUT-

Useful Expressions: Words and phrases Friends and communication: solidify/ strengthen/ enhance/ promote communication / connection with mutual understanding relationship network/circle of f r i e n d s cultivate/develop friendship with s b . keep steady relationship with sb. establish interpersonal networksac build up the social circle spur message transmission Knowledge and experience widen one’s outlook broaden one’s vision/horizon acquire knowledge and skills comprehensive/overall quality

expand/enlarge one’s scope of knowledge knowledge reserve/base/storage theoretical knowledge practical skills social experience broaden one’s knowledge base promote one’s overall/ comprehensive competence accumulate experiences learn lessons from past experiences Work and experience the scarcity of employment o p p o r t u n i t i lay the foundations for career p r o s p e r i t y

雅思口语素材

U s e f u l E x p r e s s i o n s: Words and phrases Friends and communication: mutual understanding solidify/ strengthen/ enhance/ promote communication / connection with relationship network/circle of friends cultivate/develop friendship with sb. keep steady relationship with sb. establish interpersonal networksac build up the social circle spur message transmission Knowledge and experience widen one’s outlook broaden one’s vision/horizon acquire knowledge and skills comprehensive/overall quality expand/enlarge one’s scope of knowledge knowledge reserve/base/storage theoretical knowledge practical skills social experience broaden one’s knowledge base promote one’s overall/ comprehensive accumulate experiences competence learn lessons from past experiences Work and experience the scarcity of employment opportunities lay the foundations for career prosperity immerse oneself in endless job tasks boost/augment/enhance efficiency be adept in boost one’s c ompetitiveness Health and pressure diminish individuals' leisure time drive away lassitude lighten one’s burden homework/workforce overload

近期雅思口语卡片新题素材汇总

近期雅思口语卡片新题素材汇总 人物Describe a classmate of yours Describe a good friend Describe a happy person Describe a colleague Describe a neighbor Describe your own personality Describe a family member Describe a child you know Describe an old person Describe an old person who has influenced you the most Describe a successful person Describe a singer Describe a sportsman Describe a movie star Describe a character in TV or movie Describe a teacher of yours Describe a famous person that you want to spend a day with.地点Describe a building at schools Describe a historical place

Describe a monument Describe an interesting building Describe a lake, river or sea. Describe a peaceful place Describe a leisure place Describe a park Describe a place of interest Describe a natural beauty Describe a city you want to live in Describe a place you have visited Describe a place you always go for shopping

Simon考官范文-雅思口语素材2(Cook整理)

一.雅思P2相关话题 一日假期 和外国朋友一起吃饺子的建议 1.The best way to eat a dumpling is in one bite. “Dumplings are designed to be consumed in one mouthful, as it’s the best way to enjoy the combination of the meat filling and the very thin and springy flour wrapper,” If you can’t use chopsticks, eat your dumplings with your fingers. Avoid using a fork at all costs, as piercing the dumpling will compromise the flavour. 3.Mix two parts vinegar with one part soy sauce for the perfect dumpling sauce. Add young ginger slices too， Chili oil is also a great addition when available. 4.Dumplings are just one element of dim sum. “Dim sum doesn’t just include dumplings. It’s also braised dishes like pork ribs, chicken feet, and beef balls. It’s actually small tapas-style dishes that are eaten in Cantonese restaurants at lunchtime,” 5.Xiao long bao dumplings are different from others as they contain broth. They originated in the Jiangnan region of China and are prepared in bamboo steaming baskets called xiao long, hence the name. 6.When eating xiao long bao or a dumpling with a ~soupy~ interior, opt for chopsticks and a spoon. “As soon as the dumplings arrive at your table, lift one from the steamer basket onto a soup spoon. Next, tear the skin of the dumpling by pressing the chopsticks from the side of the dumpling onto the spoon. The broth will ooze out onto the spoon. Sip the soup then enjoy the dumpling in one mouthful.” 7.You can tell whether your dumpling was cooked fresh or frozen by looking at the skin. “The skin of a freshly made dumpling is springy and light. “Frozen ones tend to be soggy.” 8.When makingdumplingsat home, try to keep your packages small.

(完整word版)雅思口语素材整理汇总

雅思口语素材训练 by Tina Li Do you like music??A—肯定:Definitely yes, everyone enjoys music, and I am no exception! I love... 否定 :Well, honestly speaking, music is really not my cup of tea, simply because... ( 给出直接原因) What—pop, techno ( 电音音乐), hip-hop, rock, meditation ( 冥想乐) and especially light music.( 罗列名词) Where—Normally speaking, I would like to listen to music with my earphones when I take a ride on public transportation. ( 给出一个具体的场景) When—As long as I couldn’t go to sleep, I’d like to listen to some light music to calm myself down. ( 给出一个条件 :As long as I..., I would...)

Who—My most favourite singers include Adele, James Blunt, Avril Lavigne, and so forth. ( 喜欢的歌手) Why—I am fond of music mainly because it can cheer me up greatly when I feel down/low/ blue/bored/tired/depressed. ( 心情不好的时候让我高兴起来)?Besides, I also believe that music is an indispensable part of culture and tradition, through which I could have a better understanding of different cultures around the world, including cowboy culture, African-American street culture, the three main reli- gions and so on. ( 有助于理解不同的文化) Do you like watching movies?? A—Speaking of movies, yes, I am a big fan of all types of movies, such as...?What—comedy, action, romance, sci-fi, manga, vampire, zombie, animation...

雅思口语part 2 素材分类整理

做有偿工作的人 Describe a person you know who is doing a paid job. You should say: Who this person is What job it is; How long the job lasted; And explain why you or this person chose to do this job. 让你笑的小孩 Describe a time that a child did something that made you laugh. You should say: When this happened Who the child was What the child did And explain why it was funny 特殊的旅行 Describe an educational trip you went on when you were in school. You should say: When and where you went; Who you went with; What you did; And explain what you learned on this trip.

Describe an electronic machine you want to buy. You should say: What it is When you know this machine What specific And explain why you want this machine 难忘的广告 Describe an unforgettable advertisement (that you saw or heard liked) You should say: Where you saw or heard it What kind of advertisement it was What the contents of the advertisement were (or, what product or service was advertised) And explain how you felt when you saw or heard this advertisement/why you like it

【2019-2020】雅思口语话题素材-精选word文档 (1页)

【2019-2020】雅思口语话题素材-精选word文档 本文部分内容来自网络整理，本司不为其真实性负责，如有异议或侵权请及时联系，本司将立即删除！ == 本文为word格式，下载后可方便编辑和修改！ == 雅思口语话题素材 雅思口语素材总结雅思口语要求学生平时多多的积累素材，在口语方面要不断的加强练习。烤鸭们要多模拟不同的场景，多用丰富的口语短语，这 样你的雅思口语水平才能越来越高。下面是常用的一些口语短语，供大家参考！ 1、 a change of pace 改变步调;换口味 You cant do these chemistry experiments all day long . You certainly need a change of pace . 2、 a far cry from 相距甚远 The published book is a far cry from the early manuscript . 3、 and how 的确 A ： Shes a good dancer . B ： And how . 4、 a matter of time 时间问题 It is only a matter of time . 5、 a phone call away 一个电话之远，即愿意过来帮忙 If you need my help , do let me know . Just remember I am a phone call away . 6、 a while back 不久以前 Well , I listened to that CD you lent me a while back . 7、 all along 一直 I knew it all along . 8、 anything but 绝对不 I was anything but happy about going . 9、 account for 解释 How do you account for it ? 10、 after all 毕竟;终究 A ： Ive just seen the X - rays and your teeth look just fine . B ： I see . Then there is nothing to worry about after all . 11、allergic to 对过敏 Oh man ! Something in this room is making my eyes itch . I must be allergic to something . 12、 at sbs service 愿为某人服务 I am at your service at any time . 13、 around the clock 24小时不停 Martha studied around the clock for management exam . 14、 as far as I know 就我所知 But as far as I know , he once won the world champion at the Olympic Games . 15、 at home with 对很熟悉 She is at home with problems like this . 16、 back out 退出 A ： Wasnt Bert supposed to sing tonight ? B ： Yes , but he backed out at last minute . 17、be cut out for 适合于，有做某事物的天赋 She is cut out for a dancer . 18、 be absorbed in 全神贯注于某事物 She has been absorbed in a horrorfiction . I cant tear her away . 19、 be addicted to 对某事物上瘾 She has been addicted to drugs for years . 20、 be attached to 对某事物有感情 A ： Im amazed that you are still driving that old car of yours . I thought you would have gotten rid of it years ago . B ： It runs well and Ive actually been quite attached to it .

雅思口语话题素材积累：Hometown

雅思口语雅思托福技巧雅思口语-美联国际教育雅思口语话题素材积累：Hometown 2014-02-18 17:00 类别：雅思口语来源：enguo 责编：meten 考生们在练习备考雅思口语过程中，可以多从身边的生活中取材，锻炼自己的口语表达能力。下面小编就为大家整理了雅思口语话题素材：Hometown，希望对大家备考有所帮助。 1、Where do you come from? 2、What tourist attractions are there in your hometown? Would a foreign visitor enjoy them? 3、Did you learn much about the history of your hometown in school? 4、What do you think needs to change in your hometown? 5、What place(s) in your hometown do you go to in your spare time? 6、Why did you choose to live here/there? 7、What do you like about your hometown? 8、What do you think needs to be done to make your hometown a better place to live in? 9、For you, what benefits are there to living in a big city? 10、What facilities does your hometown have? 11、What sorts of buildings are there in your hometown? 12、What's the most attractive part of your hometown? 13、What forms of transport do visitors use to come to your hometown? 14、How could your hometown attract more visitors? 15、Has the weather in your hometown changed much in recent years? Important: At the moment (2012) in China, there are about 30 different topics being used in Part 1. These topics and questions are in the examiner's question book(topic pool), the examiner is not allowed to make his or her own questions in Part 1 test. 众所周知，雅思口语考试是非常重视临场发挥的，虽然这些雅思口语考试试题看上去都很平常，但是还是要求大家在自己熟悉的题目和熟悉的事物中发挥自己的真实水平，所以大家一定不能掉以轻心，平时就要多加训练，在考场上正常甚至超常发挥出来。

雅思口语高分模板汇总

雅思口语高分模板汇总 多看一些雅思口语高分模板，有助于提升英语说话的逻辑，还能增强我们遣词造句的能力。下面就和大家分享，来欣赏一下吧。 雅思口语高分模板：描述兴趣爱好的话题 雅思口语高分模板一： From a middle class family, I was born in Hsin Ying, Tainan on October 10th, 1965. My father is a civil official at Tainan City Government. My mother is a house wife good at . Although I am the only child of my parents, I am by no mans a spoiled one. On the contrary, I have been expected to be . I study hard at school. Besides texts knowledge, journalism is my favorite; whenever reading, my heart is filled with great joy and interesting. 从中产阶级家庭，我出生在Hsin Ying，台南1965年10月10日。我父亲是台南市政府的一名公务员。我母亲是一位善于烹饪的家庭主妇。虽然我是我父母的独生子女，但我决不是一个被宠坏的孩子。相反，我被认为是一个成功的受过高等教育的人。我在学校努力学习。除了文字知识，新闻是我的最爱;每当阅读，我心中充满了极大的乐趣和乐趣。

各系列专业职称资格分类一览表

附件2、《各系列专业职称资格分类一览表》 国家各系列（专业）职称资格分类一览表 各系列（专业）分类 高、中、初级专业技术资格名称 正高级 副高级 中级 初级 （助理级） 初级 （员级） 工 程 系 列 建设专业 研 究 员 级 高 级 工 程 师 高 级 工 程 师 工 程 师 助 理 工 程 师 技 术 员 机械专业 纺织专业 轻工专业 冶金专业 石油化工专业 交通水路运输 专业 交通公路运输 专业 质量技术监督 专业 水利专业 水产专业 林业专业 环境保护专业 广播电影电视 工程专业 电子信息专业 煤炭专业 地质矿产专业 水文(工程、环境)地质专业 探矿专业 物化探与遥感 专业 地质实验测试 (选矿)专业 测绘专业 采矿专业 土地专业 岩土工程专业

工艺美术专业研究员级高 级工艺美术 师 高级工艺美 术师 工艺美术 师 助理工艺 美术师 工艺美术 员 农业系列 农技专业 农业技术推 广研究员 高级农艺师农艺师 助理农艺 师 技术员畜牧(兽医) 专 业 农业技术推 广研究员 高级畜牧 (兽医)师 畜牧(兽 医)师 助理畜牧 (兽医)师 技术员农业经济专业高级农经师 农经师 (考试) 助理农经 师(考试) 农经员 (考试) 财经系列 国际商务专业 高级国际商 务师 国际商务 师(执业资 格) 助理国际商 务师 (从业资格) 外销员 (从业资 格) 经济专业 研究员级高 级经济师 高级经济师 经济师 (考试) 助理经济 师(考试) 经济员 (考试) 会计专业 研究员级高 级会计师 高级会计师 (考评结合) 会计师 (考试) 助理会计 师(考试) 会计员 (考试) 统计专业高级统计师 统计师 (考试) 助理统计 师(考试) 统计员 (考试) 审计专业 高级审计师 (考评结合) 审计师 (考试) 助理审计 师(考试) 审计员 (考试) 思想政治 工作专业 研究员级高 级政工师 高级政工师政工师 助理政工 师 教师系列高校教师(思想 政治教育专职 教师) 教授副教授讲师助教 高校教管研究 专业 研究员副研究员 助理研究 员 研究实习 员 高校实验专业高级实验师实验师 助理实验 师 实验员中专校教师高级讲师讲师助理讲师教员中专实验专业高级实验师实验师 助理实验 师 实验员技工学校教师 教授级高级 讲师 高级讲师讲师助理讲师教员技校实习指导 教师 高级实习指 导教师 一级实习 指导教师 二级实习 指导教师 三级实习 指导教师党校教师 (市级以上) 教授副教授讲师助教 党校教师(县 级) 高级讲师讲师助理讲师

雅思口语考试素材

雅思口语试题参考素材 1.被污染的地方 Last vacation, I went to Hainan with my family.Hainan is such a wonderful place that I will never forget it. It's really a good place where gave me a rather good impression. I feel so wonderful during the journey, as I have experienced a lot of things for the first time. The sky is also brighter and clearer than that I had ever seen. It was my first time to experience the sea and the beach in the sunshine. When sitting on the cruise, I could clearly see the ocean waves pushing the windows of the cruise. But last week, I went to Hainan again. I went to the beach the second time, but this trip changed my idea about its scenery. There were a lot of rubbish. The water was full of flotsam and refuse.When I walked along the sea, terrible smell went into my nose.The beach had been affected by pollution.Due to poor management, people who visited there damaged the environment. It is to be regretted that a beautiful place has gone.

最全的专业技术职称分类标准

专业技术职称分类 系　列 高 级中　级 初　级正高级副高级 高等学校 教师 教授副教授讲师助理讲师 中等专业 学校教师 高级讲师讲师助理讲师、教员 技工学校教师 高级讲师讲师助理讲师、教员高级实习指导教师 一级实习指导教 师 二级实习指导教 师、三级实习指 导教师 中学教师中学高级教师中学一级教师中学二级教师、中学三级教师 小学（幼儿园）教 师 小学高级教师 小学一级教师、 小学二级教师、 小学三级教师幼儿园高级教师 幼儿园一级教 师、幼儿园二级 教师、幼儿园三 级教师 自然科学研究人员研究员 (Z) 副研究员 (Z) 助理研究员(Z)研究实习员(Z) 社会科学研究人员研究员 (S) 副研究员 (S) 助理研究员(S)研究实习员(S) 工程技术人员教授级高 级工程师 高级工程 师 工程师 助理工程师、技 术员 实验技术人员教授级高 级实验师 高级实验 师 实验师 助理实验师、实 验员 教授级高 级农艺师 高级农艺 师 农艺师 助理农艺师、农 业技术员

农业技术人员教授级高 级兽医师 高级兽医 师 兽医师 助理兽医师、兽 医技术员 教授级高 级畜牧师 高级畜牧 师 畜牧师 助理畜牧师、畜 牧技术员 卫生技术 人员主任医师 副主任 医师 主治（主管） 医师 医师、医士主任药师 副主任 药师 主管药师药师、药士主任护师 副主任 护师 主管护师护师、护士主任技师 副主任 技师 主管技师技师、技士 经济专业人员教授级高 级经济师 高级经济 师 经济师 助理经济师、经 济员 会计专业人员教授级高 级会计师 高级会计 师 会计师 助理会计师、会 计员 审计专业人员教授级高 级审计师 高级审计 师 审计师 助理审计师、审 计员 统计专业人员教授级高 级统计师 高级统计 师 统计师 助理统计师、统 计员 新闻专业人员高级记者主任记者记者助理记者高级编辑主任编辑编辑(X)助理编辑(X) 出版专业人员编审副编审编辑(C)助理编辑(C) 技术编辑 助理技术编辑、 技术设计员 一级校对 二级校对、三级 校对 图书资料专业人员研究馆员 (T) 副研究馆 员(T) 馆员(T) 助理馆员、管理 员(T) 文物博物专业人员研究馆员 (W) 副研究馆 员(W) 馆员(W) 助理馆员、管理 员(W)