發(fā)布時(shí)間：2018-04-24 09:17

  本文選題：nTiO_2 + As(Ⅲ)��； 參考：《昆明理工大學(xué)》2017年碩士論文

【摘要】：普遍存在于水環(huán)境中的砷(As)是一種易遷移、毒性強(qiáng)的污染物。由于其具有的生物累積性和生物放大作用,As污染事件一直備受關(guān)注。近年來納米二氧化鈦(nTi02)的大量生產(chǎn)和使用,由此帶來的生態(tài)風(fēng)險(xiǎn)使nTi02成為了備受關(guān)注的新興污染物。nTiO2進(jìn)入水環(huán)境后,由于其特有的納米尺度效應(yīng)、量子效應(yīng)、界面效應(yīng)及巨大的表面效應(yīng)等特殊的理化性質(zhì),會(huì)影響水體中其他污染物的環(huán)境行為,進(jìn)而影響其生態(tài)風(fēng)險(xiǎn)。為更好地認(rèn)識(shí)淡水環(huán)境中nTi02對(duì)As(Ⅲ)環(huán)境行為的影響,同時(shí)預(yù)測(cè)兩者的生態(tài)風(fēng)險(xiǎn),本研究以對(duì)污染物反應(yīng)靈敏的大型蚤(Daphnia magna)為實(shí)驗(yàn)生物,在確定As(Ⅲ)對(duì)nTi02理化性質(zhì)影響的基礎(chǔ)上,探討不同濃度nTi02下As(Ⅲ)對(duì)大型蚤的毒性(半數(shù)抑制濃度,EC50)和As(Ⅲ)在蚤體內(nèi)累積量、亞細(xì)胞分布、空間分布、代謝及潛在的作用機(jī)制。結(jié)果表明:nTi02的存在減小As(Ⅲ)對(duì)大型蚤的毒性,并且nTiO2吸附As(Ⅲ)后作為載體將As(Ⅲ)運(yùn)輸進(jìn)入蚤體,從而增加As(Ⅲ)在蚤體內(nèi)的累積。增加的As主要分布于細(xì)胞碎屑中,金屬敏感組分(MSF)中的As反而減小,增加的Ti則主要分布于生物解毒組分(BDM)中。蚤體內(nèi)As和Ti在空間分布上具有顯著正相關(guān)關(guān)系。由于吸附作用,nTiO2阻礙了蚤體對(duì)As的代謝,可極大影響蚤體對(duì)As的代謝方式。通過代謝后亞細(xì)胞的測(cè)定發(fā)現(xiàn),無nTi02存在時(shí),代謝的As主要來自于MSF及細(xì)胞碎屑,有nTiO2存在時(shí),代謝的As僅來自于細(xì)胞碎屑。代謝的Ti則主要來自于MSF,蚤體對(duì)As和Ti的解毒機(jī)制并不相同,累積于蚤體內(nèi)的AsL比Ti更容易被代謝。nTiO2可影響蚤體對(duì)重金屬的吸收、累積和代謝等生理過程。因此,除了關(guān)注nTiO2本身的環(huán)境效應(yīng),應(yīng)更多關(guān)注nTiO2對(duì)污染物環(huán)境行為的影響。
[Abstract]:Arsenic ascorbic acid (as), which is ubiquitous in water environment, is a easily transportable and highly toxic pollutant. Due to its bioaccumulation and biomagnification, as pollution events have attracted much attention. In recent years, the production and use of nano-TiO _ 2 (nTi02) in large quantities, the ecological risk caused by this, nTi02 has become a new pollutant. After entering the water environment, because of its unique nano-scale effect, quantum effect. The special physicochemical properties, such as interface effect and huge surface effect, will affect the environmental behavior of other pollutants in water, and then affect their ecological risk. In order to better understand the effect of nTi02 on the environmental behavior of As( 鈪，

本文編號(hào)：1796050