本文關(guān)鍵詞：典型氟喹諾酮類(lèi)抗生素在高嶺土上吸附特征的實(shí)驗(yàn)研究　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2017年博士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 氧氟沙星 氟甲喹 高嶺土 溶解性腐殖酸 銅離子

【摘要】：氟喹諾酮類(lèi)抗生素(Fluoroquinolone Antibiotics,FQs)在水-土壤/沉積物中已被頻繁檢出。吸附是控制其遷移轉(zhuǎn)化的重要環(huán)節(jié)。環(huán)境中共存的溶解性有機(jī)質(zhì)(Dissolved Organic Matter,DOM)與重金屬離子會(huì)影響到抗生素的吸附。溶解性腐殖酸(Dissolved Humic Acid,DHA)是DOM的主要成分之一,而Cu(II)被廣泛應(yīng)用在工農(nóng)業(yè)生產(chǎn)及動(dòng)物飼料等方面,是水環(huán)境中受人關(guān)注的重金屬離子。本文利用吸附批實(shí)驗(yàn)并輔助以微觀表征和模擬計(jì)算方法研究了Cu(II)和DHA對(duì)氧氟沙星(Ofloxacin,OFL)和氟甲喹(Flumequine,FLU)這兩種典型FQs在高嶺土上吸附與解吸的影響。主要成果如下:(1)OFL主要通過(guò)氫鍵作用和陽(yáng)離子交換作用吸附到高嶺土上。溶液離子強(qiáng)度的增大對(duì)OFL+的吸附無(wú)影響,但會(huì)抑制OFL±的吸附,由此可以判斷各形態(tài)的OFL與高嶺土間的吸附親和力大小順序?yàn)镺FL+OFL±OFL-。OFL吸附分配系數(shù)Kd(L/kg)隨pH(4.0-10.0)變化呈現(xiàn)不對(duì)稱(chēng)的“鐘形”,其最大值出現(xiàn)在pH=7.0左右。FLU在高嶺土上的吸附機(jī)理主要為氫鍵和靜電引力作用。溶液離子強(qiáng)度的增大降低了FLU的活度,導(dǎo)致其Kd值降低。FLU的吸Kd隨pH(4.0-10.0)變化也呈現(xiàn)不對(duì)稱(chēng)的“鐘形”,在pH=6.0左右達(dá)到最大。當(dāng)OFL與FLU共存時(shí),OFL與高嶺土間較強(qiáng)的親和力使其表現(xiàn)出了更強(qiáng)的競(jìng)爭(zhēng)吸附能力。二者在高嶺土上均容易發(fā)生解吸,且FLU比OFL解吸率高。(2)在溶液pH≤7.0時(shí),游離態(tài)的Cu(II)會(huì)與OFL、OFL-Cu或FLU-Cu競(jìng)爭(zhēng)吸附點(diǎn)位,從而抑制OFL或FLU在高嶺土上的吸附。絡(luò)合物Cu-OFL或CuFLU與高嶺土間的親和力均大于OFL或FLU,因而會(huì)促進(jìn)OFL或FLU的吸附。Cu(II)的抑制或促進(jìn)作用取決于二者的初始濃度。當(dāng)溶液pH7.0時(shí),Cu(II)會(huì)促進(jìn)OFL和FLU在高嶺土上的吸附,且促進(jìn)作用隨Cu(II)濃度的增大而增強(qiáng)。這是由于pH7.0時(shí),未被絡(luò)合的Cu(II)主要以Cu(OH)2的形式存在,不會(huì)競(jìng)爭(zhēng)吸附點(diǎn)位。除此之外,Cu(OFL-)2(s)會(huì)沉淀到高嶺土表面。在解吸過(guò)程中,Cu(II)會(huì)通過(guò)離子交換作用或者“絡(luò)合拖拽”方式促進(jìn)OFL在高嶺土上的解吸,而Cu(II)對(duì)FLU解吸的促進(jìn)作用是通過(guò)“絡(luò)合拖拽”的方式。(3)在不同體系中,OFL或FLU與DHA的相互作用強(qiáng)度與溶液pH有關(guān)。DHA與OFL或FLU間的結(jié)合能力隨著溶液pH的升高(4.0-10.0)而變?nèi)�。結(jié)合物DHA-OFL和DHA-FLU與高嶺土間親和力隨著溶液pH的升高而降低,因此影響著OFL或FLU在高嶺土上的吸附。在酸性條件下,共沉淀作用是目標(biāo)組分從液相轉(zhuǎn)移到固相的一個(gè)重要機(jī)理。在解吸過(guò)程中,DHA會(huì)與吸附到高嶺土上的OFL或FLU結(jié)合,將吸附在高嶺土上的目標(biāo)污染物“拖拽”下來(lái),從而促進(jìn)OFL或FLU在高嶺土上的解吸。
[Abstract]:Fluoroquinolone Antibiotics. FQs have been frequently detected in water-soil / sediment. Adsorption is an important step in controlling the migration and transformation of FQs. Dissolved Organic Matter. DOM) and heavy metal ions can affect the adsorption of antibiotics. Dissolved humic acid dissolved Humic acid (DHA) is one of the main components of DOM. CuPII is widely used in industrial and agricultural production, animal feed and so on. CuII) and DHA were used to study ofloxacin in Ofloxacin. OFLL and Flumequine. The effect of these two typical FQs on kaolin adsorption and desorption. The main results are as follows: 1). OFL was mainly adsorbed on kaolin by hydrogen bonding and cation exchange. The increase of ionic strength of solution had no effect on the adsorption of OFL. But it can inhibit the adsorption of OFL 鹵. It can be concluded that the order of adsorption affinity between various forms of OFL and kaolin is OFL OFL 鹵OFL-.OFL adsorption partition coefficient KDX L / kg with pH (. (4.0-10.0) the change presented an asymmetrical "bell shape". The adsorption mechanism of pH=7.0 on kaolin is mainly hydrogen bond and electrostatic gravitation. The increase of ionic strength decreases the activity of FLU. As a result of the decrease of K d value, the absorption of K d with pH = 4.0-10.0) also showed an asymmetric "bell shape", which reached the maximum around pH=6.0. When OFL and FLU coexisted. The strong affinity between OFL and kaolin makes them show stronger competitive adsorption ability. Both of them are easy to desorption on kaolin. Moreover, the desorption rate of FLU is higher than that of OFL. 2) when pH 鈮，

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