氧化铁纳米材料在污水处理中的应用
Review
Use of iron oxide nanomaterials in wastewater treatment:A review
Piao Xu a ,b ,Guang Ming Zeng a ,b ,?,Dan Lian Huang a ,b ,?,Chong Ling Feng a ,b ,Shuang Hu c ,Mei Hua Zhao a ,b ,Cui Lai a ,b ,Zhen Wei a ,b ,Chao Huang a ,b ,Geng Xin Xie a ,b ,Zhi Feng Liu a ,b
a College of Environmental Science and Engineering,Hunan University,Changsha 410082,PR China
b Key Laboratory of Environmental Biology and Pollution Control (Hunan University),Ministry of Education,Changsha 410082,PR China c
School of Environment,Tsinghua University,Beijing 100084,PR China
a b s t r a c t
a r t i c l e i n f o Article history:
Received 29November 2011
Received in revised form 2February 2012Accepted 10February 2012Available online 4March 2012Keywords:
Iron oxide nanomaterials Wastewater treatment Nanosorbents Photocatalysts
Immobilization carriers
Nowadays there is a continuously increasing worldwide concern for the development of wastewater treat-ment technologies.The utilization of iron oxide nanomaterials has received much attention due to their unique properties,such as extremely small size,high surface-area-to-volume ratio,surface modi ?ability,ex-cellent magnetic properties and great biocompatibility.A range of environmental clean-up technologies have been proposed in wastewater treatment which applied iron oxide nanomaterials as nanosorbents and photo-catalysts.Moreover,iron oxide based immobilization technology for enhanced removal ef ?ciency tends to be an innovative research point.This review outlined the latest applications of iron oxide nanomaterials in wastewater treatment,and gaps which limited their large-scale ?eld applications.The outlook for potential applications and further challenges,as well as the likely fate of nanomaterials discharged to the environment were discussed.
?2012Elsevier B.V.All rights reserved.
Contents 1.Introduction ...............................................................12.Iron oxide nanomaterials .........................................................23.
Iron oxide nanomaterials in wastewater treatment .............................................43.1.Adsorptive technologies .....................
.................................43.1.1.Iron oxide NMs as nanosorbents for heavy metals......................................43.1.2.Iron oxide NMs as nanosorbents for organic contaminants.
.................................53.2.Photocatalytic technology .....................................................63.3.Immobilization carriers ......................................................74.Iron oxide nanomaterials in environment .................................................75.Conclusions ...............................................................8Acknowledgments...............................................................8References .................................
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8
1.Introduction
The spread of a wide range of contaminants in surface water and groundwater has become a critical issue worldwide,due to popula-tion growth,rapid development of industrialization and long-term droughts (Cundy et al.,2008;Chong et al.,2010;Zeng et al.,2011).
It is thus of necessity to control the harmful effects of contaminants and improve the human living environment.Contaminants persisting in wastewater include heavy metals,inorganic compounds,organic pollutants,and many other complex compounds (O'Connor,1996;Fatta et al.,2011;Li et al.,2011).All of these contaminants releasing into the environment through wastewater are harmful to human be-ings and ecological environment.Consequently,the need for contam-inants removal has become a must (Jiang et al.,2006;Huang et al.,2010;Pang et al.,2011a ).
In an effort to combat the problem of water pollution,rapid and signi ?cant progresses in wastewater treatment have been made,in-cluding photocatalytic oxidation,adsorption/separation processing
Science of the Total Environment 424(2012)1–10
?Corresponding authors at:College of Environmental Science and Engineering,Hunan University,Changsha 410082,PR China.Tel.:+8673188822754;fax:+8673188823701.
E-mail addresses:zgming@https://www.wendangku.net/doc/6218258926.html, (G.M.Zeng),huangdanlian@https://www.wendangku.net/doc/6218258926.html, (D.L.
Huang).
0048-9697/$–see front matter ?2012Elsevier B.V.All rights reserved.doi:
10.1016/j.scitotenv.2012.02.023
Contents lists available at SciVerse ScienceDirect
Science of the Total Environment
j o u r n a l h o me p a g e :w ww.e l s e v i e r.c om /l o c a t e /s c i t o t e n v
and bioremediation(Huang et al.,2006a;Zelmanov and Semiat, 2008;Long et al.,2011;Pang et al.,2011a,2011b).However,their applications have been restricted by many factors,such as processing ef?ciency,operational method,energy requirements,and economic bene?t.Recently,nanomaterials(NMs)have been suggested as ef?-cient,cost-effective and environmental friendly alternative to existing treatment materials,from the standpoints of both resource conserva-tion and environmental remediation(Friedrich et al.,1998;Dimitrov, 2006;Dastjerdi and Montazer,2010).
Nanotechnology holds out the promise of immense improve-ments in manufacturing technologies,electronics,telecommunica-tions,health and even environmental remediation(Gross,2001; Kim et al.,2005;Moore,2006).It involves the production and utiliza-tion of a diverse array of NMs,which include structures and devices with the size ranging from1to100nm and displays unique proper-ties not found in bulk-sized materials(Stone et al.,2010;Wang et al., 2010).Several kinds of nanomaterials,such as carbon-based NMs (Mauter and Elimelech,2008;Upadhyayula et al.,2009)and TiO2 NMs(Khan et al.,2002;Shankar et al.,2009),have been widely stud-ied and extensively reviewed.However,iron oxide-based NMs need to be studied in greater detail.
This review evaluates the important properties of iron oxide NMs. It highlights not only recent developments in the application of iron oxide NMs for wastewater treatment,but also gaps which limited their large-scale?eld application.Primary attention is given to recent development in the utilization of iron oxide NMs as nanosorbents, followed by critical discussion on their application as photocatalysts. Furthermore,the practical potential of iron oxide based immobiliza-tion technology for improving pollutant removal ef?ciency is elabo-rated.The likely fate of NMs discharged in the environment and associated remediation method are also discussed.A detailed descrip-tion of synthesis method,properties and characterization of iron oxide NMs is beyond the scope of this article,but can be found in Laurent et al.(2008)and Teja and Koh(2009).The structure of this review is illustrated in Fig.1.
2.Iron oxide nanomaterials
Iron oxides exist in many forms in nature.Magnetite(Fe3O4), maghemite(γ-Fe2O3),and hematite(α-Fe2O3)are the most common forms(Cornel and Schwertmann,1996;Chan and Ellis,2004).In re-cent years,the synthesis and utilization of iron oxide NMs with novel properties and functions have been widely studied,due to their size in nano-range,high surface area to volume ratios and superparamagnetism(McHenry and Laughlin,2000;Afkhami et al., 2010;Pan et al.,2010).Particularly,the easy synthesis,coating or modi?cation,and the ability to control or manipulate matter on an atomic scale could provide unparalleled versatility(Boyer et al., 2010;Dias et al.,2011).Additionally,iron oxide NMs with low toxic-ity,chemical inertness and biocompatibility show a tremendous potential in combination with biotechnology(Huang et al.,2003; Roco,2003;Gupta and Gupta,2005).The unique properties,which account for the application of iron oxide NMs as well as the consider-able differences among iron oxide bulk materials,were presented in Fig.2(Bystrzejewski et al.,2009;Selvan et al.,2010).
It is reported that preparation methods and surface coating me-diums play a key role in determining the size distribution,morpholo-gy,magnetic properties and surface chemistry of nanomaterials (Jeong et al.,2007;Machala et al.,2007).Many researchers have been focusing their efforts on developing chemical and physical methods for the synthesis of MNPs(Dias et al.,2011).Recently,a va-riety of synthesis approaches have been developed to produce high quality nanoparticles(Hassanjani et al.,2011),nano-ovals(Zhong and Cao,2010),nanobelts(Fan et al.,2011)and nanorings(Goti?et al.,2011)or other nanostructures.Fig.3presents the three most important published routes for the synthesis of superparamagnetism iron oxide nanoparticles(SPIONs),summarized by Mahmoudi et al. (2011).Advances in NMs synthesis enable the precise control of surface active sites by manufacturing monodisperse and shape-controlled iron oxide NMs(Bautista et al.,2005;Li and Somorjai, 2010).Some emerging methods,such as fungi/proteins mediated biological method and sonochemical method,necessitate wide de-velopment.Future studies should aim to address different challenges to provide new ef?cient and speci?c magnetic NMs.In addition,the development of iron oxide NMs into a?eld scale may provide a pro-ductive area of research,and more research is required to explore the application potential of these novel NMs.
Generally,nanomaterials should be stable to avoid aggregation and endow a low deposition rate,in order to assure their reactivity and mobility(Schrick et al.,2004;Kanel et al.,2007;Tiraferri et
al.,
Fig.1.Overview of the review structure.
2P.Xu et al./Science of the Total Environment424(2012)1–10
Fig.2.Important properties of iron oxide magnetic nanoparticles for wastewater treatment
applications.
Fig.3.A comparison of published work (up to date)on the synthesis of SPIONs by three different routes.Sources:Institute of Scienti ?c Information.(Adopted from (Mahmoudi et al.,2011)).
3
P.Xu et al./Science of the Total Environment 424(2012)1–10
2008).However,it is reported that NMs tend to aggregate in solution (Lin et al.,2005).Commonly,the stability of colloidal nanoparticles is in?uenced by the electrostatic and van der Waals interactions (Chen et al.,2007).Much work is still needed to advance knowledge in the enhancement of NMs stability,by reducing their surface energy which limits their large-scale application.One attractive potential approach is the modi?cation of NMs,based on the fact that iron oxide NMs could react with different functional groups.The use of stabilizer,electrostatic surfactant,and steric polymers has been wide-ly proposed for facilitating NMs with non-speci?c moieties,group speci?c,or highly speci?c ligands(Hyeon et al.,2001;Harris et al., 2003;Batalha et al.,2010;Sung et al.,2012).
The stability of iron oxide colloid suspensions could be greatly augmented by surface modi?cation with suitable functional groups, such as phosphonic acids,carboxylic acid,and amine(Fig.4)(Boyer et al.,2010;Dias et al.,2011).Since the practical application depends on the type of modi?ed medium,it would be critical to functionalize with various mediums(Mohanraj and Chen,2007).A series of me-diums can be tuned to introduce various functional groups to iron oxide NMs,but a robust protocol to achieve this has yet to be developed and demonstrated.Nanomaterials that are sterically stabilized tend to remain well-dispersed even in industrial application(Tiraferri et al., 2008).It should be noted that the application of iron oxide NMs are strongly related to their intrinsic properties,which highly depend on the preparation method and modi?cation mediums(Machala et al., 2007;Girginova et al.,2010).
3.Iron oxide nanomaterials in wastewater treatment
Selection of the best method and material for wastewater treat-ment is a highly complex task,which should consider a number of factors,such as the quality standards to be met and the ef?ciency as well as the cost(Huang et al.,2008;Oller et al.,2011).Therefore, the following four conditions must be considered in the decision on wastewater treatment technologies:(1)treatment?exibility and ?nal ef?ciency,(2)reuse of treatment agents,(3)environmental secu-rity and friendliness,and(4)low cost(Zhang and Fang,2010;Oller et al.,2011).
Magnetism is a unique physical property that independently helps in water puri?cation by in?uencing the physical properties of contaminants in water.Adsorption procedure combined with mag-netic separation has therefore been used extensively in water treat-ment and environmental cleanup(Ambashta and Sillanp??,2010;Mahdavian and Mirrahimi,2010).Iron oxide NMs are promising for industrial scale wastewater treatment,due to their low cost,strong adsorption capacity,easy separation and enhanced stability(Hu et al., 2005;Carabante et al.,2009;Fan et al.,2012).The ability of iron oxide NMs to remove contaminants has been demonstrated at both labora-tory and?eld scale tests(White et al.,2009;Girginova et al.,2010). Current applications of iron oxide NMs in contaminated water treat-ment can be divided into two groups:(a)technologies which use iron oxide NMs as a kind of nanosorbent or immobilization carrier for removal ef?ciency enhancement(referred to here as adsorptive/ immobilization technologies),and(b)those which use iron oxide NMs as photocatalysts to break down or to convert contaminants into a less toxic form(i.e.photocatalytic technologies).However,it should be noted that many technologies may utilize both processes.
3.1.Adsorptive technologies
3.1.1.Iron oxide NMs as nanosorbents for heavy metals
Heavy metal contamination is of great concern because of its toxic effect on plants,animals and human beings,and its tendency for bioac-cumulation even at relatively low concentration.Therefore,effective removal methods for heavy metal ions are extremely urgent and have attracted considerable research and practical interests(Huang et al., 2006a;Chen et al.,2011;Pang et al.,2011c).
Nowadays,the majority of bench-scale research and?eld applica-tions of materials for wastewater treatment has focused on magnetic NMs(Iram et al.,2010),carbon nanotubes(Sta?ej and Pyrzynska, 2007),activated carbon(Kobya et al.,2005),and zero-valent iron (Ponder et al.,2000).Among these,it seems that iron oxide magnetic NMs,possessing the capability to treat large volume of wastewater and being convenient for magnetic separation,are most promising mate-rials for heavy metal treatment(Hu et al.,2010).The iron oxide NMs could illustrate excellent superiority.In a study performed by Nassar (2010),it was found that the maximum adsorption capacity for Pb(II) ions was36.0mg g?1by Fe3O4nanoparticles,which was much higher than that of reported low cost adsorbents.The small size of Fe3O4 nanosorbents was favorable for the diffusion of metal ions from solu-tion onto the active sites of the adsorbents surface.It recommended that Fe3O4nanosorbents were effective and economical adsorbents for rapid removal and recovery of metal ions from wastewater ef?uents.
However,as one of the most important surface-driven phenom-ena in aquatic environments,aggregation caused by high
surface https://www.wendangku.net/doc/6218258926.html,mon chemical moieties for the anchoring of polymers and functional groups at the surface of iron oxide magnetic nanoparticles(Adopted from(Dias et al.,2011)). 4P.Xu et al./Science of the Total Environment424(2012)1–10
area to volume ratios of NMs could control a number of important environmental processes,including ion uptake(Baalousha,2009). In addition to aggregation,numerous interactions occurred in waste-water also affect the adsorption of metals.For example,phosphates can be well adsorbed and can out-compete metals for adsorption sites due to their high concentrations in wastewater(Feng et al., 2010).Therefore,the above mentioned factors as well as the types of contaminants may limit the effectiveness of nanosorbents,and the exploration of highly effective modi?cation methods for NMs tends to be a hot research?eld for enhancing the ef?ciency of nano-sorbents.Surface modi?cation,which can be achieved by the attach-ment of inorganic shells and/or organic molecules,not only stabilizes the nanoparticles and eventually prevents their oxidation,but also provides speci?c functionalities that can be selective for ion uptake and thus enhance the capacity for heavy metal uptake in water treatment procedures.Several types of functionalized materials have been utilized by grafting of chelating ligands on the surface of NMs for heavy metal removal(Ambashta and Sillanp??,2010; Girginova et al.,2010).For example,Bystrzejewski et al.(2009)ap-plied carbon-encapsulated magnetic nanoparticles to remove Cu2+ and Cd2+.In their study,the ion uptakes achieved95%for cadmium and copper,which were considerably higher than the capacities of activated carbons,con?rming the prospect of modi?ed iron oxide NMs for ef?cient heavy metal removal from aqueous solutions.
Mechanisms of contaminant adsorption from wastewater by modi-?ed iron oxide NMs include surface sites binding(Hu et al.,2010),mag-netic selective adsorption(Ozmen et al.,2010),electrostatic interaction (Zhong et al.,2006),and modi?ed ligands combination(Hao et al., 2010).The addition of novel modi?cation mediums to NMs can achieve high ef?ciency.For example,a novel magnetic nanosorbent(MNP–NH2)has been developed by the covalent binding of1,6-hexadiamine on the surface of Fe3O4nanoparticles for the removal of Cu2+ions from aqueous solution(Hao et al.,2010).The chemisorptions occurred between Cu2+and NH2groups on the surface of MNP–NH2,as shown in Eq.(1).In addition,the prepared nanosorbents had good reusability and stability,and the adsorption capacity of MNP–NH2was kept constant (about25mg g?1).This further con?rmed their application potential, not only considering removal ef?ciency,but also taking into account the practical application.
MNP–MH2tCu2t→MNP–NH2Cu2te1TLaboratory studies indicated that iron oxide NMs could effectively remove a range of heavy metals,including Pb2+,Hg2+,Cd2+,Cu2+ et al.A list of functionalized iron oxide NMs with their sorption capac-ity values was summarized in Table1.However,iron oxide-based technology for heavy metal adsorption is still at a relatively early stage for wide application.It is recognized that much work is needed to advance knowledge in the area of NMs,and the transfer of iron oxide NMs from laboratory to?eld-scale application involves many complexities.With increasing trends in contaminant removal treat-ment,more data of NMs will become available on performance and cost,which can provide additional information for large-scale indus-trial application(Otto et al.,2008).
3.1.2.Iron oxide NMs as nanosorbents for organic contaminants
As a well-known separation process,adsorption has been widely applied to remove chemical pollutants from water.It has numerous ad-vantages in terms of cost,?exibility and simplicity of design/operation, and insensitivity to toxic pollutants(Zeng et al.,2007;Ahmad et al., 2009;Rafatullah et al.,2010).Therefore,an effective and low-cost ad-sorbent with high adsorption capacity for organic pollutants removal is desirable.Iron oxide NMs are currently being explored for organic contaminant adsorption,particularly for the ef?cient treatment of large-volume water samples and fast separation via employing a strong external magnetic?eld.A lot of experiments have been undertaken to examine the removal ef?ciency of organic pollutants by using iron oxide NMs for organic pollutants(Zhang et al.,2010;Zhao et al.,2010; Luo et al.,2011).For example,Fe3O4hollow nanospheres were shown to be an effective sorbent for red dye(with the maximum adsorption capacity of90mg g?1)(Iram et al.,2010).The saturation magnetiza-tion of prepared nanospheres was observed to be42emu g?1,which was suf?cient for magnetic separation with a magnet(critical value at 16.3emu g?1)(Ma et al.,2005).These proved that magnetic NMs tech-nology was a novel,promising and desirable alternative for organic contaminant adsorption.
Similar to heavy metal adsorption,the adsorption of organic con-taminants took place via surface exchange reactions until the surface functional sites are fully occupied,and thereafter contaminants could diffuse into adsorbent for further interactions with functional groups (Ma et al.,2005;Zhao et al.,2010;Hu et al.,2011).Based on this mechanism,the development of NMs for organic contaminant re-moval requires an extension of surface modi?cation.The modi?cation and chemical treatment of NMs are essential to enhance the target adsorption capability.One example in this area is the use of carbon coated Fe3O4nanoparticles(Fe3O4/C)to extract trace PAHs(Zhang et al.,2010).The recoveries of experimental PAHs on Fe3O4/C nano-sorbents were signi?cantly increased compared with those pure Fe3O4nanoparticles,and the removal ef?ciencies of target compounds were above90%for PhA,FluA,Pyr,BaA,and BbF,as shown in Fig.5.In addition,through this method,the presence of carboxyl and hydroxyl groups could modify Fe3O4/C nanoparticles with hydrophilic surface. The modi?ed nanoparticles can then not only be dispersed stably in solution for practical applications,but also decrease the irreversible
Table1
Functionalized iron oxide magnetic nanomaterials in heavy metal adsorption.
Nanosorbents Ligands Heavy metals Adsorption capacity Reference
Mesostructured silica magnetite–NH2Cu(II)The adsorbents showed a capacity of0.5mmol/g for Cu(II).(Kim et al.,2003)
Magnetic iron–nickel oxide–Cr(VI)The prepared adsorbent showed a maximum of30mg/g
uptake capability for Cr(VI).
(Wei et al.,2009)
Montmorillonite-supported MNPs–AlO;–SiO Cr(VI)The adsorption capacity was15.3mg/g for Cr(VI).(Yuan et al.,2009)
PEI-coated Fe3O4MNPs–NH2Cr(VI)The maximum adsorption capacity for Cr(VI)was83.3mg/g.(Pang et al.,2011b)
δ-FeOOH-coatedγ-Fe2O3MNPs–Cr(VI)The Cr(VI)adsorption capacity determined to be25.8mg/g.(Hu et al.,2007)
Flower-like iron oxides–As(V),Cr(VI)The As(V)adsorption capacity was5.3mg/g.(Li and Zhang,2006)
Hydrous iron oxide MNPs–As(V),Cr(VI)8mg of arsenic per g of adsorbent.(Pradeep,2009)
Fe3O4–silica Si–OH Pb(II),Hg(II)The removal ef?ciency was97.34%and90%for Pb(II)and Hg(II),
respectively.
(Ambashta and Sillanp??,2010)
Amino-modi?ed Fe3O4MNPs–NH2Cu(II),Cr(VI)The maximum adsorption capacity was12.43mg/g for Cu(II)
ions and11.24mg/g for Cr(VI)ions,respectively.
(Huang and Chen,2009)
m-PAA-Na-coated MNPs–COO Cu(II),Pb(II)et al.Adsorption capacity:Cd(II)(5.0mg g?1);Pb(II)(40.0mg g?1);
Ni(II)(27.0mg g?1)and Cu(II)(30.0mg g?1).
(Mahdavian and Mirrahimi,2010)
Poly-L-cysteine coated Fe2O3MNPs–Si–O;–NH2Ni(II),Pb(II)et al.The recovery of the tested metals were almost all above50%,
even the removal ef?ciency of Ni(II)reached89%.(White et al.,2009)
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adsorption of analytes to overcome the desorption problem of carbon materials.
In summary,combination of the superior adsorption performance and magnetic properties of iron oxide NMs tend to be a promising ap-proach to deal with a variety of environmental problems.Advances in iron oxide NMs could provide opportunities for developing next-generation adsorption systems with high capacity,easy separation,and extended lifecycles.The novel physical,chemical and magnetic properties of iron oxide NMs can facilitate many advanced applications in the development of adsorptive technologies,and thus generate more ef ?cient and cost-effective remediation approaches as compared with conventional technologies (Babel and Kurniawan,2003;Cundy et al.,2008;Brar et al.,2010).3.2.Photocatalytic technology
Photocatalysis,one of the advanced physico-chemical technology applicable in photodegradation of organic pollutants (Akhavan and Azimirad,2009),has attracted much attention in recent years.How-ever,some obstacles hinder the wide application of iron oxide NMs for the photocatalysis of toxic compounds:(a)the separation of ma-terials after the treatment process tends to be expensive owing to manpower,time and chemicals used for precipitation followed by centrifugation or decantation at the end of treatment process,and (b)the low quantum-yield of treatment process restricts the kinetics and ef ?ciency (Bandara et al.,2007).These limitations should be taken into account for the development of NMs based technologies.Considerable efforts have been made to enhance photocatalytic activity,such as decreasing photocatalyst size to increase surface area,combin-ing photocatalyst with some novel metal nanoparticles,and increasing hole concentration through doping (Zhang and Fang,2010).On the other hand,improved charge separation and inhibition of charge car-rier recombination are essential in improving the overall quantum ef ?ciency for interfacial charge transfer (Beydoun et al.,1999;Watson et al.,2002;Hu et al.,2009).
Iron oxide NM can be a good photocatalyst absorbing visible https://www.wendangku.net/doc/6218258926.html,pared with commonly applied TiO 2,which mainly absorbs UV light with wavelengths of b 380nm (covering only 5%of the solar spectrum)due to its wide band-gap of 3.2eV,Fe 2O 3with band-gap of 2.2eV (Akhavan and Azimirad,2009)is an interesting n-type semi-conducting material and a suitable candidate for photodegradation under visible light condition.The better photocatalytic performance of iron oxide NMs than TiO 2can be attributed to considerable
generation of electron –hole pairs through the narrow band-gap illu-mination (Eq.(2))(Bandara et al.,2007).Fe 2O 3thv →Fe 2O 3ee ?
cb ;h t
vb T
e2T
Many species of Fe(III)oxides have been proposed,such as α-Fe 2O 3,γ-Fe 2O 3,α-FeOOH,β-FeOOH and γ-FeOOH,to degrade organic pollut-ants and reduce their toxicity due to enhanced photocatalysis effect (Wu et al.,2000).These NMs are illustrative of a new way to manipulate the catalytic properties of iron oxide for photocatalysis,towards a safe and effective wastewater treatment nanotechnology.An example is the photodegradation of Congo red (CR)dye (C 32H 24N 6O 6S 2)by iron oxide nanoparticles which were synthesized by thermal evaporation and co-precipitation approach (Khedr et al.,2009).The maximum re-moval ef ?ciency was 96%at a size of 100nm.Further,irradiation was found to have no pronounced effect on the catalytic decomposition ca-pacity,but the rate of degradation was fast in the presence of light.
Iron oxide NMs have been widely applied as photocatalysts,but their activity decline is frequently encountered because of the elec-tron –hole charge recombination on the oxide surface,as fast as with-in nanoseconds (Rothenberger et al.,1985).Deposition of a noble metal on a metal oxide support can be employed to address this problem.For example,gold/iron oxide aerogels were used as photo-catalysts to degrade disperse Blue 79azo dye in water under ultravi-olet light illumination (Wang,2007).In the photocatalysis system,metallic gold particles,which were considered to function as the sites for electron accumulation under UV light irradiation,could facili-tate the transfer of surface electrons.The better separation between electrons and holes would allow a better ef ?ciency for oxidation and reduction reactions (Liu et al.,2004),thus enhancing the photocatalytic activity.Meanwhile,hydroxyl radicals near the catalyst surface,acting as the main oxidative species to attack dye molecules,were ef ?cient to improve dye degradation.The combination of metals with iron oxide nanomaterials can increase the kinetics of oxidation –reduction reaction,and tend to be an effective approach for photocatalytic im-provement (Otto et al.,2008).
In addition,due to its narrow band-gap,Fe 2O 3can be applied as a sensitizer of TiO 2photocatalyst (Zhang and Lei,2008;Akhavan and Azimirad,2009).Electrons in the valence bands of TiO 2are driven into Fe 2O 3due to formation of the built-in ?eld in Fe 2O 3–TiO 2heterojunc-tion.The charge transport between the valance bands of Fe 2O 3and TiO 2is regarded as an effective process to promote photocatalytic activ-ity of the composition,since it results in an increase in the electron –hole recombination time (Peng et al.,2010a;Shinde et al.,2011).
Recently,a novel photo-Fenton-like system has been set up with the existence of iron oxides and oxalate (Lei et al.,2006).Iron oxides were mainly acted as a photocatalyst,while oxalic acid could be excit-ed to generate electron –hole pairs (Leland and Bard,1987;Siffert and Sulzberger,1991).The heterogeneous iron oxide –oxalate system could exhibit a strong ligand-to-metal charge transformation ability as described below (Lei et al.,2006):
Firstly,oxalic acid can be adsorbed by iron oxide particles to form iron oxide –oxalate complexes including [Fe III (C 2O 4)n ](2n ?3)?or [Fe II (C 2O 4)n-1]4?2n on the surface in solution,which are much more photoactive than other Fe 3+species,with the generation of oxalate
radical C 2O 4??
.Iron oxide tnH 2C 2O 4??≡Fe eC 2O 4Tn
e2n à3T?
e3T
?≡Fe eC 2O 4Tn
e2n à3T?
thv →Fe eC 2O 4T2?2or e≡Fe eC 2O 4T2?2TtCO 2?
?
e4T
?Fe III eC 2O 4Tn
e2n à3T?
thv →?Fe II eC 2O 4Tn à1
4à2n
tC 2O 4?
?
e5
T
Fig.5.Removal ef ?ciencies of PAHs by Fe3O4and Fe3O4/C nanosorbents (Adopted
from (Zhang et al.,2010)).
6P.Xu et al./Science of the Total Environment 424(2012)1–10
Then,a rapid de-carboxylation is followed.Oxalate radical is transferred into carbon-centered radicalCO2??,then further trans-formed into superoxide ion(O2??).
C2O4??→CO2tCO2??e6TC2O4??tO2→CO2tO2??e7TFinally,O2??produces H2O2and O2by disproportion.?OH,generated in their redox–oxidize transformation process accompanied with the production and consumption of H2O2,as described below,plays a key role in the photodegradation process.
Fe3ttO2??→?Fe2ttO2e8TO2??tnHttFe2t→Fe3ttH2O2e9TFe2ttH2O2→Fe3ttOH?t?OHe10TAccording to above equations,photolysis of Fe(III)–oxalate com-plexes forms H2O2,Fe3+could result in the radical chain mechanism described above,and the Fenton reaction(Eq.(10))is enhanced by the participation of Fe2+.Therefore,the photochemical reduction of Fe(III)-complex will be coupled to a Fenton reaction,with the produc-tion of oxidative species such as superoxide(O2??),hydroperoxyl (H2O2)and OH radicals(Quici et al.,2005)by utilizing natural mate-rials(iron oxides and oxalic acid)to produce?OH without external H2O2and arti?cial injection of iron(Faust and Zepp,1993).In short, photo-Fenton-like system can provide a promising and effective meth-od for photocatalysis of organic pollutants,possessing great application potential.It is also important to not only enhance the photocatalyst ability but justify the combination of iron oxide NMs with microbes (or other organisms)secreting oxalic acid or other organic acids on the basis of photocatalyst,therefore expanding the application of iron oxide NMs in removal of organic contaminants.
3.3.Immobilization carriers
Iron oxide NMs have also shown considerable potential in the immobilization of biomass.The biosorption capacity of a variety of macro and microbial biomass has been widely used to remove various pollutants.NMs can offer larger surface areas and multiple sites for interaction or adsorption(Paljevac et al.,2007).In particular,due to the advantage of chemical inertness and favorable biocompatibility, iron oxide NMs have been widely used in immobilization technology (Huang et al.,2003;Sulek et al.,2010).
A great deal of efforts has been made by various researchers (Jolivalt et al.,2000;Jiang et al.,2005;Huang et al.,2006b)to develop effective immobilization technology.Immobilization of biomass onto a more rigid and open support has been extensively studied for fungi and microalgae(Li et al.,2010).In fact,immobilized cells have been attracting great attention since the1970s,mainly due to their dis-tinct advantages over dispersed cells(McHale and McHale,1994). First of all,the immobilization of native biomass enhances physical characteristics and offers a higher level of activity(Rodriguez,2009). In addition,resistance to environmental perturbations such as pH,tem-perature and toxic chemical concentrations can be enhanced(Shin et al.,2002).Moreover,immobilization is conducive to cyclic biomass utilization,easier liquid–solid separation and minimal clogging in continuous-?ow systems.Such advantages could satisfy the engineer-ing needs for application of immobilization technology.
Appropriate techniques must be combined to provide technically sound and economically feasible options(Oller et al.,2011).Recently,Saccharomyces cerevisiae immobilized on the surface of chitosan-coated magnetic nanoparticles(SICCM)was applied as a novel mag-netic adsorbent for the adsorption of Cu(II)from aqueous solution (Peng et al.,2010b).In the study of Peng et al.(2010b),a series of experiments were performed to examine the removal ef?ciency of the prepared adsorbents.It was found that SICCM was quite ef?cient as a magnetic adsorbent for the adsorption of Cu(II).The removal ef?ciency reached over90%within20min,and the maximum ad-sorption capacity reached134mg g?1.Hopefully this kind of novel adsorbent will have broad applications in the removal of heavy metals from wastewater.It is thus reasonable to presume that immo-bilization of biomass on suitable support is a precondition for the use of biosorbents in large-scale processing.In addition,more studies should be conducted to optimize the adsorbent,mainly by selecting proper strains which have great adsorption ability to heavy metals and organic compounds.
Although lots of immobilization mediums and methods have been investigated,little information is available on combining iron oxide nanotechnology with other biological technology for environmental application,which may show a great application prospect by combin-ing respective advantages of both NM and biomass.Thus it is of great importance to study not only the large-scale application of adsorp-tion method but also immobilization technology with high capacity and stability.Future studies may need to draw the?eld of magnetic NMs into biological applications such as nano-biosensors,cells/ proteins immobilization for magnetic separation and environmental improvement.There is an emerging need for iron oxide NM immobi-lization technology to be applied in environmental treatment.As a result,it is of signi?cance to select suitable biomass which possesses favorable adsorption capacity and is well compatible with magnetic NMs.In combined chemical and biological wastewater treatment,it is also very important to keep in mind how the characteristics of each individual treatment process can improve the destruction of a persistent contaminant(Oller et al.,2011).In addition,commercial issues such as scale up of the preparation of a biocatalyst or biosensor by immobilization of enzymes or microbes have to be assessed in com-petition with existing materials(Wang et al.,2008).It is anticipated that the practical performance will increase signi?cantly after combining with biotechnology and iron oxide-based technology,and large-scale ?eld application will also expand to a great extent.
4.Iron oxide nanomaterials in environment
It is recognized that there are many potentially serious issues con-cerning the environmental fate of engineered NMs and their potential impacts on human health.Currently,there are very few information on the background concentrations and physical–chemical forms of NMs in the environment due to limitations in separation and analyt-ical methodologies,although some laboratory based studies have been carried out.However,such information is urgently required and a major advance in knowledge would come through the develop-ment of accurate and robust methodologies for the measurement of NMs concentration and form in the environment(Ju-Nam and Lead, 2008).A de?nitive need exists to evaluate the effects that NMs may have on the environment,yet little is known regarding interactions of NMs with environmental matrices,either naturally or in the test environment(Darlington et al.,2009).
First of all,it is imperative to identify the ecotoxicity of NMs in aquatic systems,or focus on transport in a terrestrial environment with an aim of prediction of NM behavior and evaluation of exposure pathways.Nanomaterials,that are near commercialization and are produced in large quantities,will enter the aquatic environment, resulting in direct exposure to humans via skin contact,inhalation of water aerosols and direct ingestion of contaminated drinking water(Nel,2006).Thus the study of toxicity and pathology is ex-tremely important(Gatti and Rivasi,2002).Since there is so little
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data available for the fate of discharged NMs,research is required to test the behavior and particulate binding properties of manufactured NMs with ecosystem and human beings.But it is noted that cells and tissues have effective antioxidant defenses that deal with reactive oxygen species generation by NMs(Bell,2003).Throughout their uptake and transport through the body,NMs will encounter a num-ber of defenses that can eliminate,sequester,or dissolve NMs.
The unique characteristics of NMs will necessitate new test strat-egies to delineate the novel mechanisms of injury that may arise from these materials.Risk assessment is of key importance to the reg-ulatory agencies that are responsible for formulating exposure and safety guidelines(Nel,2006).Predicting the physical behaviors and biological toxicity of NMs is likely to be much more dif?cult than pre-dicting those of conventional chemical pollutants,which is still often a major problem(Bucheli and Gustafsso,2000;Moore,2006).A major challenge for ecological risk identi?cation will be the derivation of toxicity thresholds for NMs,and determining whether or not current-ly available biomarkers of harmful effect will also be effective for en-vironmental nanotoxicity and nanopathology.It is therefore necessary that effective risk assessment procedures are in place as soon as possible to deal with potential hazards of NMs(Galloway et al.,2002;Galloway et al.,2004;Moore,2006).It is also important for regulatory agencies to develop positive and negative benchmarks that can be used as reference controls(Nel,2006).
In general,the attention on this?eld is still not enough,and addi-tional studies should be conducted to advance knowledge in the area of safety and biocompatibility studies.In particular,for long-term toxicity studies,the potential impacts on human and environmental health should be essentially addressed.More re?ned methods for NM characterization and toxicological evaluations will be emerging. For example,some of speci?c nanosensors tend to be an available ap-proach to detect ROS generation by nanoparticles.This could make these evaluations cost effective,facilitating new product develop-ment(Nel,2006).
5.Conclusions
Wastewater treatment and reuse is a practice related not only to a number of bene?ts in regards to water balances and management but also to a number of question marks.Immediate research must be launched towards this direction so as to safeguard human health and environmental ecosystems.Nanomaterials,with unique physical and chemical properties,have a tremendous potential for contami-nants removal.To bring the NMs development a step forward,NMs prioritization and further application prospect have been presented. As a kind of effective photocatalysts,iron oxide NMs would display their dominant superiority even at a source of visible light.In fact, iron oxide NMs are ef?cient nanosorbents for heavy metals and or-ganic pollutants.Employing iron oxide NMs to adsorb heavy metals and organic pollutants are the most attractive and successful applica-tions.While applications as immobilization carriers are only sparsely addressed,the potential of utilization as support carriers,consisting of biosensors and biosorbents,could not be ignored.
Although many cases of success in NMs were bene?ted from their unique chemical and physical properties,the applications of NMs in wastewater treatment are still limited in the early stage.As illustrated in this review,a range of iron oxide-based technologies have been proposed or are under active development for wastewater treatment, but many techniques are still at an experimental or pilot stage.Poten-tial dif?culties may be encountered in application in vitro and in vivo studies with iron oxide NMs.The?eld of iron oxide NMs(in a variety of chemical and structural forms)has already exhibited its diversity and potential applications in many frontiers of environmental area.
In conclusion,there is much recent interest in the use of engi-neered iron oxide NMs as an in-situ,relatively non-invasive tool in wastewater treatment.But it is noted that uncertainties over the health impacts and environmental fate of these nanomaterials need to be addressed before their widespread application.Increasingly, study of their fate and impact in the environment is becoming impor-tant due to the discharges already occurring to the environment.The likely further increase in NMs discharges along with the dramatic in-dustry growth,and the immense knowledge gaps in risk assessment and management,would necessitate expanding studies in this area. Acknowledgments
The study was?nancially supported by the Programs for Changjiang Scholars and Innovative Research Team in University(IRT0719),the National Natural Science Foundation of China(50808073,50978088, 51039001),the Hunan Key Scienti?c Research Project(2009FJ1010), the Environmental Protection Technology Research Program of Hunan (2007185),the Hunan Provincial Natural Science Foundation of China(10JJ7005)and the New Century Excellent Talents in University (NCET-08-0181).
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纳米材料应用现状及发展趋势
NANO MATERIAL NANO MATERIAL NANO MATERIAL 纳米材料 应用现状及发展趋势 北京有色金属研究总院李明怡 摘要纳米材料是近期发展起来的多功能材料,本文概述了纳米材料的结构特性、主要制备工艺及应用现状和发展趋势,由于纳米材料具有许多特殊功能和效应,将在工业和国防等领域中发挥巨大潜力,并将为人类社会带来巨大影响。 关键词纳米结构功能材料制备工艺应用现状发展趋势 1前言 纳米材料是指由极细晶粒组成,特征维度尺寸在1~100纳米范围内的一类固体材料,包括晶态、非晶态和准晶态的金属、陶瓷和复合材料等,是80年代中期发展起来的一种新型多功能材料。由于极细的晶粒和大量处于晶界和晶粒内缺陷中心的原子,纳米材料在物化性能上表现出与微米多晶材料巨大的差异,具有奇特的力学、电学、磁学、光学、热学及化学等诸方面的性能,目前已受到世界各国科学家的高度重视。以纳米材料及其应用技术为重要组成部分的纳米科学技术,被认为对当代科学技术的发展有着举足轻重的作用。美国IB M公司首席科学家Ar mstrong认为:/正像70年代微电子技术产生了信息革命一样,纳米科学技术将成为下一代信息的核心。0我国科学家钱学森也指出:/纳米左右和纳米以下的结构将是下一阶段科学技术发展的重点,会是一次技术革命,从而将引起21世纪又一次产业革命。0由于纳米科学技术具有极其重要的战略意义,美、英、日、德等国都非常重视这一技术的研究工作。美国国家基金会把纳米材料列为优先支持项目,拨巨款进行专题研究。英国从1989年起开始实施/纳米技术研究计划0。日本把纳米技术列为六大尖端技术探索项目之一,并提供1187亿美元的专款发展纳米技术。我国组织实施的新材料高技术产业化专项中也将纳米材料列为其中之一。纳米材料正在向国民经济和高技术各个领域渗透,并将为人类社会进步带来巨大影响。 2纳米材料的结构和特性 我们所使用的常规材料在三维方向上都有足够大的尺寸,具有宏观性。纳米材料则是一些低维材料,即在一维、二维甚至三维方向上尺寸极小,为纳米级(无宏观性),故纳米材料的尺寸至少在一个方向上是几个纳米长(典型为1~10nm)。如果在三维方向上都是几个纳米长,为3D纳米微晶,如在二维方向上是纳米级的,为2D纳米材料,如丝状材料和纳米碳管;层状材料或薄膜等为1D纳米材料。纳米颗粒可以是单晶,也可以是多晶,可以是晶体结构,也可以是准晶或无定形相(玻璃态);可以是金属,也可以是陶瓷、氧化物或复合材料等。纳米微晶的突出特征是晶界原子的比例很大,有时与晶内的原子数相等。这表明纳米微晶内界面很多,平均晶粒直径越小,晶界 20
气体在污水处理中的应用
气体在污水处理中的应用 杨冰倩12化41 12234014 摘要：随着我国工业的快速发展，环境污染问题也变得日益严重，特别是在水污染方面的问题日益突出。本文分别探讨了氧气、臭氧和过氧化氢三种气体在污水处理中的应用，主要论述了氧气在污水处理的各个环节中所起的作用。 关键词：氧气臭氧过氧化氢污水处理应用 Application of Gas in Treating Wastewater Abstract：With the rapid development of our country industry,theenvironmental pollution problem has become increasingly serious, especially in water pollution problem increasingly prominent.This paper discusses the three gas oxygen, ozone and hydrogen peroxide application in wastewater treatment，mainly discusses the oxygen in the wastewater treatment of the role of each part Key words：Oxygen;Ozone;Hydrogen peroxide;Sewage treatment;application 活性污泥法处理污水通过空气供氧,向盛有活性污泥的曝气池中连续鼓入空气,以满足好氧微生物的生存、繁殖需要,从而改善活性污泥的性质,提高污水处理效果。除此之外，氧气在污水处理的其他环节也有作用，例如曝气池沉砂池，以及作为一种新型污水处理技术的曝气生物滤池。臭氧作为一种强氧化剂,不仅具有优异的消毒作用,而且在水处理中同时具有去除水中的色、臭、味以及一些 无机化学物质。Ｈ ２Ｏ ２ 是一种全面有效的杀菌剂，杀菌速度快。本文通过以上三 种气体来阐述气体在污水处理中的应用。 1.氧气在污水处理中的应用 1.1曝气沉沙池 曝气沉砂池就是在池的一侧通进空气的沉砂池。池内的污水在空气引导下成螺旋形向前流动(即旋流)。污水在这种周边到中心逐渐减少的旋流流速作用下,砂粒被带到池底的集砂槽中而被分离。污水中的有机物,包括从砂面上冲刷下来的污泥都处于悬浮状态,并随水流进入后面的处理构筑物。国外从五十年代开始
纳米氧化铁
第一章综述 1.1 概述 1.1.1 氧化铁的性质 纳米科学技术是20世纪80年代末诞生并崛起的新科技，它的基本内涵是指在-9-7）范围内认识和改造自然，通过直接和安排原子，分子创造1010～纳米尺寸（新物质，以及改造原有物质使其具有新的性质[1]。纳米材料具有量子尺寸效应，小尺寸效应，表面效应及宏观量子隧道效应等基本特性[1]。这些基本特性使纳米材料具有不同与常规材料的潜在的物理，化学性质，因此引起人们的广泛兴趣。纳米氧化铁( nano- sized iron oxide) 具有良好的耐候性、耐光性、磁性 和对紫外线具有良好的吸收和屏蔽效应, 可广泛应用于闪光涂料、油墨、塑料、皮革、汽车面漆、电子、高磁记录材料、催化剂以及生物医学工程等方面, 且可望开发新的用途[2，3]。 通常，铁的氧化物及其羟基氧化物均归属于氧化铁系列化合物，按价态，晶型结构的不同可以分为（α-﹑β-﹑γ-）FeO ﹑FeO ﹑FeO 和（α-﹑β-﹑γ-） 4323FeOOH.按色泽又可以分为，红﹑黄﹑橙﹑棕﹑黑。较具实用价值的有，α- FeO32﹑β- FeO ﹑α- FeOOH﹑FeO等。43321.1.2 氧化铁的应用 1 纳米氧化铁在装饰材料中的应用 在颜料中, 纳米氧化铁又被称为透明氧化铁( 透铁) 。所谓透明, 并非特指粒子本身的宏观透明, 而是指将颜料粒子分散在有机相中制成一层漆膜( 或称油膜) , 当光线照射到该漆膜上时, 如果基本不改变原来的方向而透过漆膜, 就称该颜料粒子是透明的。透明氧化铁主要有5 个品种, 即透铁红、黄、黑、绿、棕。透明氧化铁颜料因其有0.01μm 的粒径, 因而具有高彩度、高着色力和高透明度, 经特殊的表面处理后具有良好的研磨分散性。透明氧化铁颜料可用于油化与醇酸、氨基醇酸、丙烯酸等漆料制成透明色漆, 有良好的装饰性。此种透明漆既可单独, 也可和其他有机彩色颜料的色浆相混, 如加入少量非浮性的铝粉浆则可制成有闪烁感的金属效应漆; 与不同颜色的底漆配套, 可用于汽车、自行车、仪器、仪表、木器等要求高的装饰性场合。透铁颜料强烈吸收紫外线的特性使其可作为塑料中紫外线屏蔽剂,而用于饮料、医药等包装塑料中。纳米FeO 在32 1 静电屏蔽涂料中也有广阔的应用前景, 日本松下公司已研制成功具有良好静电屏蔽的FeO 纳米涂料。这种具有半导体特性的纳米粒子在室温下具有比常规的23氧化物高的导电性, 因而能起到静电屏蔽作用。 2 纳米氧化铁在油墨材料中的应用 透铁黄可用于罐头外壁的涂装, 透铁红油墨为红金色, 特别适合罐头内壁用, 加之透铁红耐300 ℃的高温, 是油墨中难得的颜料珍品。为提高钞票的印制质量, 往往在印钞油墨中加入纳米氧化铁颜料来保证钞票的色度和彩度等指标。 3 纳米氧化铁在着色剂中的应用 随着人们生活水平的提高, 人们越来越重视医药、化妆品、食品中使用的着色剂, 无毒着色剂成了人们关注的焦点。纳米氧化铁在严格控制砷和重金属含量的情况
纳米材料的发展及应用
课程名称：化工新材料概论姓名：邓元顺 学号：1208110201 专业：化学工程与工艺班级：化工122
浅析纳米材料的发展及应用 摘要：纳米材料是纳米级结构材料的简称。狭义是指纳米颗粒构成的固体材料， 其中米颗粒的尺寸最多不超过100nm。广义是指微观结构至少在一维方向上受纳米尺度（1-100nm）限制的各种固体超细材料。【2】纳米技术是当今世界最有前途的决定性技术。纳米材料在力学、磁学、电学、热学、光学和生命等方面的重要作用和应用前景。 Abstract：Nanometer material is the abbreviation of nano structured materials.The narrow sense refers to the solid material of nano particles, in which the size of the meter particles is not more than 100nm. Generalized refers to a variety of solid ultrafine materials which are limited by nano scale (1-100nm) in the one-dimensional direction at least in one dimension.. Nanotechnology is the most promising technology in the world today. Nano materials in mechanics, magnetism, electricity, heat, optics and life and so on the important role and the application prospect. 关键词：纳米材料纳米技术发展应用 前言：纳米材料和纳米结构无论在自然界还是在工程界都不是新生事物。在自然界存在大量的天然纳米结构，只不过在透射电镜的应用以前人们没有发现而已。在工程方面，纳米材料80年代初发展起来的，纳米材料其粒径范围在1—100nm之间，故纳米材料又称超微晶材料。它包括晶态、非晶态、准晶态的金属、陶瓷和复合材料等。由于极细的晶粒和大量处于晶界和晶粒缺陷中心的原子，纳米材料的物化性能与微米多晶材料有着巨大的差异，具有奇特的力学、电学、瓷学、光学、热学及化学等多方面的性能，从而使其作为一种新型材料在电子、冶金、宇航、化工、生物和医学等领域展现出广阔的应用前景。目前已受到世界各国科学家的高度重视。美国的“星球大战计划”、“信息高速公路”，欧共体的“尤里卡计划”等都将纳米材料的研究列入重点发展计划；日本在10年内将投资250亿日元发展纳米材料和纳米科学技术；英国也将发展纳米材料科学技术作为重振英国工业的突破；我国的自然科学基金“863”计划、“793”计划以及国家重点实验室都将纳米材料列为优先资助项目。【1】美国科学技术委员会把“启动纳米技术的计划看作是下一次工业革命的核心” 一、纳米材料的发展史 1965年诺贝尔物理学奖获得者、美国加利福尼亚工学院教授费曼(R.P.Feynman)曾在1959年预言：“如果有一天可以按照人的意志来安排一个个原子，将会产生怎样的奇迹？”
纳米金属材料的发展与应用综述
纳米金属材料的发展与应用 摘要：纳米技术的诞生将对人类社会产生深远的影响，可能许多问题的发展都与纳米材料的发展息息相关。在纳米金属材料的研究中，它的制备、特性、性能和应用是比较重要的方面。本文概要的论述了纳米材料的发现发展过程，并结合当今纳米金属材料研究领域最前沿的技术和成果，简述了纳米材料在各方面的应用及其未来的发展前景。 关键词：纳米金属材料、纳米技术、应用 一、前言 纳米级结构材料简称为纳米材料(nanomater material)，是指其结构单元的尺寸介于1纳米～100纳米范围之间。由于它的尺寸已经接近电子的相干长度，它的性质因为强相干所带来的自组织使得性质发生很大变化。并且，其尺度已接近光的波长，加上其具有大表面的特殊效应，因此其所表现的特性，例如熔点、磁性、光学、导热、导电特性等等，往往不同于该物质在整体状态时所表现的性质。 纳米粒子异于大块物质的理由是在其表面积相对增大，也就是超微粒子的表面布满了阶梯状结构，此结构代表具有高表能的不安定原子。这类原子极易与外来原子吸附键结，同时因粒径缩小而提供了大表面的活性原子。 纳米技术在世界各国尚处于萌芽阶段，美、日、德等少数国家，虽然已经初具基础，但是尚在研究之中，新理论和技术的出现仍然方兴未艾。我国已努力赶上先进国家水平，研究队伍也在日渐壮大。 二、纳米材料的发现和发展 1861年，随着胶体化学的建立，科学家们开始了对直径为1~100nm的粒子体系的研究工作。1990年7月在美国召开了第一届国际纳米科技技术会议（International Conference on Nanoscience &Technology)，正式宣布纳米材料科学为材料科学的一个新分支。自20世纪70年代纳米颗粒材料问世以来，从研究内涵和特点大致可划分为三个阶段： 第一阶段（1990年以前）：主要是在实验室探索用各种方法制备各种材料的纳米颗粒粉体或合成块体，研究评估表征的方法，探索纳米材料不同于普通材料的特殊性能；研究对象一般局限在单一材料和单相材料，国际上通常把这种材料称为纳米晶或纳米相材料。 第二阶段（1990~1994年）：人们关注的热点是如何利用纳米材料已发掘的物理和化学特性，设计纳米复合材料，复合材料的合成和物性探索一度成为纳米材料研究的主导方向。 第三阶段（1994年至今）：纳米组装体系、人工组装合成的纳米结构材料体系正在成为纳米材料研究的新热点。国际上把这类材料称为纳米组装材料体系或者纳米尺度的图案材料。它的基本内涵是以纳米颗粒以及它们组成的纳米丝、管为基本单元在一维、二维和三维空间组装排列成具有纳米结构的体系。 三、纳米材料的应用 1、纳米磁性材料 在实际中应用的纳米材料大多数都是人工制造的。纳米磁性材料具有十分特别的磁学性质，纳米粒子尺寸小，具有单磁畴结构和矫顽力很高的特性，用它制成的磁记录材料不仅音质、图像和信噪比好，而且记录密度比γ-Fe2O3高几十
纳米材料及其应用前景
纳米材料及其应用前景 摘要:21世纪，纳米技术、纳米材料在科技领域将扮演重要角色。纳米技术是当今世界最有前途的决定性技术之一。本文简要地概述了纳米材料的基本特性以及其在力学、磁学、电学、热学等方面的主要应用，并简单展望了纳米材料的应用前景。 关键词：纳米材料；功能；应用； 一、纳米材料的基本特性 所谓纳米材料是指材料基本构成单元的尺寸在纳米范围即1~100纳米或者由他们形成的材料。由于纳米材料是由相当于分子尺寸甚至是原子尺寸的微小单元组成，也正因为这样，纳米材料具有了一些区别于相同化学元素形成的其他物质材料特殊的物理或是化学特性例如：其力学特性、电学特性、磁学特性、热学特性等，这些特性在当前飞速发展的各个科技领域内得到了应用。科学家们和工程技术人员利用纳米材料的特殊性质解决了很多技术难题，可以说纳米材料特性促进了科技进步和发展。 1、力学性质 高韧、高硬、高强是结构材料开发应用的经典主题。具有纳米结构的材料强度与粒径成反比。纳米材料的位错密度很低，位错滑移和增 殖符合Frank-Reed模型，其临界位错圈的直径比纳米晶粒粒径还要大，增殖后位错塞积的平均间距一般比晶粒大，所以纳米材料中位错滑移和 增殖不会发生，这就是纳米晶强化效应。金属陶瓷作为刀具材料已有50 多年历史，由于金属陶瓷的混合烧结和晶粒粗大的原因其力学强度一直 难以有大的提高。应用纳米技术制成超细或纳米晶粒材料时，其韧性、 强度、硬度大幅提高，使其在难以加工材料刀具等领域占据了主导地位。 使用纳米技术制成的陶瓷、纤维广泛地应用于航空、航天、航海、石油 钻探等恶劣环境下使用。 2、热学性质 纳米材料的比热和热膨胀系数都大于同类粗晶材料和非晶体材料的值，这是由于界面原子排列较为混乱、原子密度低、界面原子耦合作用 变弱的结果。因此在储热材料、纳米复合材料的机械耦合性能应用方面 有其广泛的应用前景。例如Cr-Cr2O3颗粒膜对太阳光有强烈的吸收作 用，从而有效地将太阳光能转换为热能。 3、电学性质 由于晶界面上原子体积分数增大，纳米材料的电阻高于同类粗晶材料，甚至发生尺寸诱导金属——绝缘体转变（SIMIT）。利用纳米粒子的 隧道量子效应和库仑堵塞效应制成的纳米电子器件具有超高速、超容量、超微型低能耗的特点，有可能在不久的将来全面取代目前的常规半导体 器件。2001年用碳纳米管制成的纳米晶体管，表现出很好的晶体三极管 放大特性。并根据低温下碳纳米管的三极管放大特性，成功研制出了室 温下的单电子晶体管。随着单电子晶体管研究的深入进展，已经成功研 制出由碳纳米管组成的逻辑电路。
纳米铁基材料的制备及其催化降解有害污染物机理的研究
纳米铁基材料的制备及其催化降解有害污染物机理的研究 随着工业的发展,环境污染日益严重,水资源的安全也受到了严重威胁,对水环境污染的控制和处理已成为当前研究热点。基于活性自由基反应的高级氧化技术被广泛应用于水处理领域。 铁基材料稳定性好且廉价易得,作为催化剂应用前景广阔。本文制备了5种不同形貌的纳米氧化铁,研究其催化降解盐酸四环素的过程及机理;利用化学气相沉积法制备了三维结构的Fe@GNS/GF复合材料,并对其结构进行表征,探讨了Fe@GNS/GF复合材料催化降解刚果红和甲基紫的过程。 本论文主要内容如下:（1）采用沉淀法制备了5种不同形貌的纳米氧化铁,分别为片状、棒状、木瓜状、立方状、球状结构。利用扫描电子显微镜、X射线衍射、比表面积分析对5种不同相貌纳米氧化铁进行了表征。 这5种纳米氧化铁尺寸均一、比表面积接近。以盐酸四环素为目标污染物研究其催化活性。 自由基清除实验和ESR分析表明反应过程中羟基自由基和超氧自由基同时发挥氧化作用。研究表明:纳米氧化铁形貌是影响催化活性的关键因素之一。 （2）以棒状纳米Fe2O3为催化剂,在 Fe2O3/H2O2非均相芬顿体系下降解盐酸四环素,并考察了双氧水浓度、催化剂投加量、pH、反应温度对降解过程的影响。分析降解过程中间产物,推断出了盐酸四环素降解途径。 动力学分析和热力学分析表明:降解过程符合二级动力学模型,反应活化能为53.37 kJ/mol。催化剂多次循环使用和铁离子渗出实验表明,催化剂具有良好的稳定性。
纳米氧化铁材料的制备与现代发展.
课题名称MITobj004 姓名 院系 专业班级 指导教师 2009 年10 月01 日
摘要纳米氧化铁的制备方法有沉淀法、固液气相法、水热法、凝胶—溶胶法、共混包埋法、单体聚合法等.。本文通过分析比较各种纳米氧化铁的制备方法, 水热法由于操作简单、粒子可控等优点广泛应用于自分散氧化物的制备研究中。 关键词水热法，沉淀法，固液气相法，比较 前言 定，催化活性高，具有良好的耐光性、耐候性和对紫外线的屏蔽性，在精细陶瓷、塑料制品、涂料、催化剂、磁性材料以及医学和生物工程等方面有着广泛的应用价值和前景，因此研究纳米氧化铁有着很重要的意义。由于纳米氧化铁具有如此多的优点及其广泛的应用前景，近年来国内外研究者对其制备和应用投入了大量的研究工作。本文综述了纳米氧化铁制备方法的一些研究进展，分析了当前急需解决的问题，并对今后发展做了展望。重点介绍了水热法制备纳米氧化铁材料，以及在铁离子浓度、PH值、水解时间分别不同的情况下的水解程度。【1】 文献综述 国内外研究现状： 我国纳米材料和纳米结构的研究已有10年的工作基础和工作积累，在“八五”研究工作的基础上初步形成了几个纳米材料研究基地，科院上海硅酸盐研究所、南京大学、科院固体物理所、科院金属所、物理所、国科技大学、清华大学和科院化学所等已形成我国纳米材料和纳米结构基础研究的重要单位。无论从研究对象的前瞻性、基础性，还是成果的学术水平和适用性来分析，都为我国纳米材料研究在国际上争得一席之地，促进我国纳米材料研究的发展，培养高水平的纳米材料研究人才做出了贡献。在纳米材料基础研究和应用研究的衔接，加快成果转化也发挥了重要的作用。目前和今后一个时期内这些单位仍然是我国纳米材料和纳米结构研究的坚力量。【2】 近年来美国纳米技术研究与产品开发发展迅速。如医学领域的纳米医药机器人、纳米定向药物载体、纳米在基因工程蛋白质合成中的应用，微电子及信息技术领域的导电聚合物在信息技术的应用、纳米电子元器件FET二极管、用于感应器的电子序列、纳米传感器，化工领域的利用纳米材料提高催化剂的效能等，都取得了很大进展。 日本科学家在2003年12月发现，当温度降到极端低时，非常接近于一维金属的碳纳米管的电阻急剧增大，变成绝缘体，与普通金属的导电性截然相反。从
浅谈纳米材料应用及发展前景
Jiangsu University 浅谈纳米材料应用及发展前景
摘要 纳米材料展现了异常的力学、电学、磁学、光学特性、敏感特性和催化以及光活性，为新材料的发展开辟了一个崭新的研究和应用领域。纳米技术在精细陶瓷、微电子学、生物工程、化工、医学等领域的成功应用及其广阔的应用前景使得纳米材料及其技术成为目前科学研究的热点之一，被认为是世纪的又一次产业革命。纳米材料向国民经济和高新科技等各个领域的渗透以及对人类社会的进步的影响是难以估计的。 关键词：纳米材料；纳米应用；量子尺寸效应 1.前言 纳米材料和纳米结构无论在自然界还是在工程界都不是新生事物。在自然界存在大量的天然纳米结构，只不过在透射电镜的应用以前人们没有发现而已。 在工程方面，纳米材料80年代初发展起来的，纳米材料其粒径范围在1—100nm之间，故纳米材料又称超微晶材料。它包括晶态、非晶态、准晶态的金属、陶瓷和复合材料等。由于极细的晶粒和大量处于晶界和晶粒缺陷中心的原子，纳米材料的物化性能与微米多晶材料有着巨大的差异，具有奇特的力学、电学、瓷学、光学、热学及化学等多方面的性能，从而使其作为一种新型材料在电子、冶金、宇航、化工、生物和医学等领域展现出广阔的应用前景。目前已受到世界各
国科学家的高度重视。美国的“星球大战计划”、“信息高速公路”，欧共体的“尤里卡计划”等都将纳米材料的研究列入重点发展计划；日本在10年内将投资250亿日元发展纳米材料和纳米科学技术；英国也将发展纳米材料科学技术作为重振英国工业的突破；我国的自然科学基金“863”计划、“793”计划以及国家重点实验室都将纳米材料列为优先资助项目[1]。美国科学技术委员会把“启动纳米技术的计划看作是下一次工业革命的核心”[2]。 2.纳米材料的制备 现行的纳米材料制备方法很多。但是真正能够高效低成本制备纳米材料的方法还是现在各个国家研究的重点。目前已报的工艺方法主要有以下几种：物理气相沉积法（PVD）和化学气相沉积法（CVD）、等离子体法、激光诱导法、真空成型法、惰性气体凝聚法、机械合金融合法、共沉淀法、水热法、水解法、微孔液法、溶胶—凝胶法等等。 3.纳米材料的主要应用 3.1纳米材料在工程方面的应用 纳米材料的小尺寸效应使得通常在高温下才能烧结的材料如SiC 等在纳米尺度下在较低的温度下即可烧结,另一方面,纳米材料作为烧结过程中的活性添加剂使用也可降低烧结温度,缩短烧结时间。纳米粉体可用于改善陶瓷的性能，其原因在于微小的纳米微粒不仅比表面积大，而且扩散速度快，因而进行烧结时致密化的速度就快，烧结
纳米材料研究现状及应用前景要点
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开题报告填写要求 1．开题报告（含“文献综述”）作为毕业设计（论文）答辩委员会对学生答辩资格审查的依据材料之一。此报告应在指导教师指导下，由学生在毕业设计（论文）工作前期内完成，经指导教师签署意见及所在专业审查后生效； 2．开题报告内容必须用黑墨水笔工整书写或按教务处统一设计的电子文档标准格式（可从教务处网页上下载）打印，禁止打印在其它纸上后剪贴，完成后应及时交给指导教师签署意见； 3．“文献综述”应按论文的格式成文，并直接书写（或打印）在本开题报告第一栏目内，学生写文献综述的参考文献应不少于15篇（不包括辞典、手册）； 4．有关年月日等日期的填写，应当按照国标GB/T 7408—94《数据元和交换格式、信息交换、日期和时间表示法》规定的要求，一律用阿拉伯数字书写。如“2004年4月26日”或“2004-04-26”。
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一、文献调研部分（获取综述的参考文献—精读全文）1．利用中文（期刊、学位论文、会议论文）数据库，检出中文切题题录（批量），选择记录文摘格式10篇（其中学位论文要求不少于2篇、期刊论文6篇）； [1]叶灵. 纳米材料的应用与发展前景[J]. 科技资讯. 2011(20) 摘要: 很多人都听说过"纳米"这个词,但什么是纳米,什么是纳米技术,可能很多人并不一定清楚。着名的诺贝尔奖获得者Feyneman在20世纪60年代曾经预言:如果我们对物体微小规模上的排列加以某种控制的话,我们就能使物体得到大量的异乎寻常的特性,就会看到材料的性能产生丰富的变化。他所说的材料就是现在的纳米材料。 [2]赵雪石. 纳米技术及其应用前景[J]. 适用技术市场. 2000(12) 摘要: 纳米技术在精细陶瓷、微电子学、生物工程、化工、医学等领域的成功应用及其广阔的前景,使得纳米技术成为目前科学研究的热点之一,被认为是21世纪的又一次产业革命。 [3]何燕,高月,封文江. 纳米科技的发展与应用[J]. 沈阳师范大学学报(自然科学版). 2010(02) 摘要：纳米科技是21世纪的主导产业,世界各国把纳米科技的研究和应用作为战略重点。在第五次科学技术革命中,新材料家族被推上新一轮科技革命的顶峰。在新材料和新技术中,纳米材料和纳米技术无疑将成为核心材料和核心技术。纳米技术的最终目标是直接操纵单个原子和分子,制造新功能器件,从而开拓人类崭新的生活模式。文章概述了纳米科技的发展过程及纳米材料的性质与制备,介绍了纳米技术在部分领域的应用,并简述了纳米技术对未来社会的巨大影响及潜在的、令人鼓舞的发展前景。 [4]何彦达. 纳米材料的应用及展望[J]. 科技风. 2010(01) 摘要：纳米材料(尺寸在1-100纳米范围内)又称超细微粒、超细粉末,是处在原子簇和宏观物体交界过渡区域的一种典型系统,其结构既不同于体块材料,也不同于单个的原子。其特殊的结构层次使它拥有一系列新颖的物理和化学特性,在众多领域特别是在光、电、磁、催化等方面具有非常重大的应用价值。 [5]樊东黎. 纳米技术和纳米材料的发展和应用[J]. 金属热处理. 2011(02) 摘要：<正>2005年12月在克利夫兰召开了由美国金属学会和克利夫兰纳摩网主办的美国纳米技术应用峰会。许多实体企业,如波音、福特、通用、洛克希德、蒂姆肯等公司高管出席会议和发言。会议的特点是着重于纳米。 [6]张桂芳. 纳米材料应用与发展前景概述[J]. 黑龙江科技信息. 2009(16) 摘要：由于独特的微结构和奇异性能,纳米材料引起了科学界的极大关注,成为世界范围内的研究热点,以下概述了纳米材料的应用与发展前景。 [7]杨萍. 多功能复合纳米材料的制备及其光分析应用研究[D]. 中国科学技术大学 2012 摘要：纳米材料具有独特的化学、物理和生物性能,引起了人们的极大关注。多功能复合结构纳米材料能够将不同功能的纳米材料整合到一个纳米器件中,从而为现代工业、生物医学
铁基纳米材料的合成,性能及在环境中的应用
铁基纳米材料的合成，性能及在环境中的应用 摘要：由于纳米级金属材料的特殊性能，人们开始对研究其在环境工程中的应用的研究越来越感兴趣。本文是一篇关于铁的纳米材料环境中的应用的综述文献，它们在水、废水处理以及空气污染控制中的应用。详细讨论了纳米铁基颗粒在环境中的应用，包括去除含氯有机物、重金属及无机物。 关键词：环境应用，纳米颗粒，性能 一引言 米级金属材料是指有着纳米级颗粒和结构，大小范围在在1到100nm的金属。近期的研究表明许多这些材料的性质取决于其在纳米级机制的颗粒大小【1】。此外，纳米材料的结构也同样会导致其物理化学性质新奇重大的变化。例如，磁性材料的强大磁力会发生改变【2】，表面反应和催化性能得以提高【3】，机械强度会增加五倍甚至更多【1】。在结构问题上，纳米颗粒的表明效应极其重要。例如，当从微米颗粒缩小至纳米级范围时，微晶的表面化学会下降，并且会发现它们独特的化学反应。同样，它们巨大而独特的比表面积使得纳米颗粒在宏观尺度产生表面能，因此会影响它们的综合性质。对于3mn左右的特定纳米球形颗粒，大约有50%的原子或电子是在表面，使得其控制综合性质成为可能。因此，表面结构的最优化可能有效提高纳米颗粒的整体行为。 在环境中的应用，铁基纳米材料被证明是清洁受污染土壤和地下水非常有效的工具。由于铁基纳米材料粒径较小，因此其比传统的铁粉活性更高，且可在溶液中分散并很容易直接泵送至污染区。铁元素本身没有毒性效应，考虑到它是地球上含量最丰富的金属之一，当暴露于空气中，铁元素会被氧化成砖红色的氧化铁，当有机污染物如TCA，TCE，PCE或四氯化碳等有机化合物遇到氧化铁时，会被降解成为简单的低毒含碳化合物。此外，氧化的铁可以还原重金属如铅、镍或汞等成为不可溶形式，使其能够锁在土壤中。因此，本文详细阐述详细讨论了纳米铁基材料的制备、性能以及其在环境中的应用。 二在环境中的应用 与微米颗粒相比，由于具有高的比表面积和更多的表面反应点，纳米级铁级颗粒有着更高的反应率。而且，由于它们可以在悬浮液中保持，纳米铁颗粒可以注入进污染的土壤、沉积物和蓄水层中。但由于纳米铁颗粒的聚合性，其很难在悬浮液中稳定存在。Schrick 等认为碳能够有效抑制聚合并纳米铁颗粒的传输性【4】。许多报告显示纳米铁已经被用作补救地下水、土壤和空气的通用材料，不管是在实验室还是在野外规模。同样也有报道称纳米铁可以与多种环境污染物有效反应，包括含氯有机物、重金属以及无机物。可被纳米铁降解的常见环境污染物在表1中有列举。
微生物在污水处理中的应用研究
微生物在污水处理中的应用研究 摘要水污染问题是环境污染的主要问题之一，已经受到社会大众的广泛关注。在污水处理工艺中，微生物处理技术显现出明显的优势，已经得到了广泛研究。基于此，本文探讨了微生物在污水处理中的应用，详述了微生物在污水处理中所使用的技术，并对微生物在污水处理中存在的问题进行了讨论，以此供大家分享交流。 关键词微生物；污水处理；原理；应用；问题 1 微生物污水处理机制与净化原理 针对不同的污染物，微生物的净化方式也有所差异，主要包括以下三种：①降解有机物，部分细菌、真菌、藻类可通过吞食将污水中一些复杂的有机物转化为简单的无机物分子，从而实现各种生命元素在自然中的循环，维持生态平衡。这种方式可有效处理尿素、氨基酸、蛋白质等含氮有机物，从而净化城市生活污水。②代谢作用，污水中存在大量不能被微生物食用的有机污染物，其中有些可以作为代谢能源来维持微生物的生命活动。例如，一些放线菌和杆菌在从广泛存在于餐厅污水的脂肪中获取新陈代谢所需能量的过程实际上也起到了污水净化的作用。③祛毒素作用，微生物主要通过改变污染物的分子结构减弱其毒性。如对于洗衣粉中的有毒磷元素，微生物可以通过将无机磷酸盐拆分为无毒性的有机酸和二氧化碳来去除。但是由于污水成分和微生物分解过程都较为复杂，这种处理方式可能产生有毒的中间物质，造成二次污染，因此在应用过程中必须要进行严格的监视[1]。 2 微生物污水处理技术的应用 2.1 微生物吸附技术 微生物吸附技术是利用某些微生物的化学结构特性，将自身或者其分泌物与污水中的悬浮物质结合在一起，形成一种活性生物吸附剂，再人为地进行固液分离。这种技术较为新颖，并且价格低廉，目前多应用于大面积重金属污水的处理。 微生物吸附技术在应用过程中受到很多因素的影响：①温度和pH值：这两个因素会严重影响污水中重金属离子的化学状态和微生物的活性，从而影响氧化还原过程和沉淀反应等；②吸附时间：研究表明，微生物吸附重金属的过程仅需几个小时，适当延长吸附时间可以提高吸附效率，因此在应用中要在保持细胞活性的前提下适当平衡吸附时间；③共存离子，污水的成分往往较为复杂，净化水质的一个关键在于保留原有的无害物质，如钙离子、钠离子、钾离子等轻金属离子，这就需要对污水成分和微生物的吸附性做一个全面的了解，防止过渡净化。 2.2 微生物絮凝技术
纳米氧化铁材料
纳米氧化铁材料 班级：材料化学091班姓名：林赚学号：091304101 摘要：氧化铁纳米粒子是一种新型的磁功能材料，被广泛应用于生物、材料以及环境等众 多领域。本文介绍了超顺磁氧化铁纳米粒子的制备方法，比较了各种方法的优缺点；评述了磁性氧化铁纳米粒子在细胞、蛋白质和核酸分离及生物检测中的应用，对多功能复合磁性氧化铁纳米粒子的构建，在生物医学领域中的应用具有的指导意义。 关键词：超顺磁性氧化铁纳米粒子；制备；生物分离；生物检测 1 引言 磁性纳米粒子是近年来发展起来的一种新型材料，因其具有独特的磁学特性，如超顺磁性和高矫顽力，在生物分离和检测领域展现了广阔的应用前景。同时，因磁性氧化铁纳米粒子具有小尺寸效应、良好的磁导向性、生物相容性、生物降解性和活性功能基团等特点，在核磁共振成像、靶向药物、酶的固定、免疫测定等生物医学领域表现出潜在的应用前景。但由于其较高的比表面积，强烈的聚集倾向，所以通常对其表面进行修饰，降低粒子的表面，能得到分散性好、多功能的磁性纳米粒子。对磁性纳米粒子的表面进行特定修饰，如果在修饰后的粒子上引入靶向剂、药物分子、抗体、荧光素等多种生物分子，可以改善其分散稳定性和生物相容性，以实现特定的生物医学应用。此外，适当的表面修饰或表面功能化还可以调节磁性纳米粒子表面的反应活性，从而使其应用在细胞分离、蛋白质纯化、核酸分离和生物检测等领域。 2 磁性氧化铁纳米粒子的合成方法 磁性纳米粒子的制备是其应用的基础。目前已发展了多种合成和制备方法，如共沉淀法、水热合成法、溶胶凝胶法和微乳液法等，上述方法均可制备高分散、粒度分布均匀的纳米粒子，并能方便地对其表面进行化学修饰。 在这些合成方法当中，共沉淀法是水相合成氧化铁纳米粒子最常用的方法。该方法制备的磁性纳米颗粒具有粒径小，分散均匀，高度生物相容性等优点，但制得的颗粒存在形状不规则，结晶差等缺点。通过在反应体系中加入柠檬酸，可得到形状规则、分散性好的纳米粒子。利用这种方法合成的磁性纳米材料被广泛应用在生物化学及生物医学等领域。微乳液法制备纳米粒子，产物均匀、单分散，可长期保持稳定，通过控制胶束、结构、极性等，可望从分子规模来控制粒子的大小、结构、特异性等。微乳液合成的磁性纳米粒子仅溶于有机溶剂，其应用受到限制。通常需要在磁性纳米粒子的表面修饰上亲水分子，使其溶于水，从而能应用于生物、医学等领域。 热分解法是有机相合成氧化铁纳米粒子最多也是最稳定的方法。利用热分解法制备的纳米Fe3O4颗粒产物具有好的单分散性，且呈疏水性，可以长期稳定地分散于非极性有机溶