【摘要】：石化、化工企業(yè)發(fā)生污染事故后,場(chǎng)地易受高濃度毒性有機(jī)物污染。毒性有機(jī)物揮發(fā)或溶解發(fā)生遷移,會(huì)對(duì)場(chǎng)地周圍大氣、土壤和地下水環(huán)境造成危害,因而需要快速固定污染物,防治其蔓延擴(kuò)散。石灰是危險(xiǎn)廢物處理和污染場(chǎng)地修復(fù)中常用的固化/穩(wěn)定化基材,但用于固定高濃度毒性有機(jī)物時(shí),主要依賴微觀結(jié)構(gòu)包封作用,有機(jī)物易揮發(fā)和溶出,固定能力相對(duì)較弱。對(duì)石灰粉體表面進(jìn)行改性,使其具有“疏水親油”特性,可提高其對(duì)特定毒性有機(jī)污染物的定向捕獲與固定能力,對(duì)事故情況下高濃度毒性有機(jī)物污染土壤的快速固化/穩(wěn)定化具有重要意義。為開(kāi)發(fā)事故情況下高濃度毒性有機(jī)物污染土壤快速穩(wěn)定化劑,本論文以石灰的主要礦物組分——氧化鈣(CaO)為基材,選擇硬脂酸(Stearic Acid,SA)和硅烷偶聯(lián)劑KH570(Silane Coupling Agent KH570,KH570)作為兩種改性劑,采用濕法工藝對(duì)CaO粉體進(jìn)行表面疏水改性,探討不同工藝條件對(duì)改性效果的影響,并對(duì)改性后CaO的形態(tài)和結(jié)構(gòu)進(jìn)行表征。以接觸角指標(biāo)為疏水性強(qiáng)弱判定依據(jù),硬脂酸改性CaO的最佳工藝條件為:SA添加質(zhì)量分?jǐn)?shù)5%,改性溫度30℃,改性時(shí)間30min;KH570改性CaO的最佳工藝條件為:KH570添加量0.02mL/gCaO,改性時(shí)間40min。改性后CaO的接觸角均大于90°。傅里葉紅外和掃描電鏡分析表明,兩種改性劑均以化學(xué)吸附方式包覆在CaO表面,達(dá)到了表面疏水改性的目的。選取硝基苯作為代表性毒性有機(jī)物,以改性CaO為穩(wěn)定化劑,對(duì)高濃度硝基苯污染土壤進(jìn)行固化/穩(wěn)定化,采用硝基苯揮發(fā)率、浸出率與固定率三個(gè)指標(biāo)對(duì)疏水改性CaO的快速固化/穩(wěn)定化效果進(jìn)行評(píng)價(jià)。結(jié)果表明,30%添加量的疏水改性CaO作為穩(wěn)定化劑能夠顯著抑制土壤中硝基苯的揮發(fā)和浸出,SA改性CaO和KH570改性CaO對(duì)硝基苯的固定率分別達(dá)到82.9%和75.6%,SA改性CaO對(duì)硝基苯的固定效果略優(yōu)于KH570改性CaO。疏水改性CaO具有強(qiáng)化吸附作用,未改性CaO具有微觀結(jié)構(gòu)包封作用,二者聯(lián)合使用(先添加疏水改性CaO混合攪拌均勻,再添加未改性CaO)對(duì)硝基苯具有更為顯著的固定效果。20%的SA改性CaO與10%的未改性CaO聯(lián)合使用,養(yǎng)護(hù)3d后硝基苯的固定率可達(dá)91.1%;20%的KH570改性CaO與10%的未改性CaO聯(lián)合使用,養(yǎng)護(hù)3d后硝基苯的固定率可達(dá)89.2%。疏水改性CaO與未改性CaO可聯(lián)合使用,作為事故情況下高濃度毒性有機(jī)物污染土壤的快速固化/穩(wěn)定化材料。
[Abstract]:After the pollution accident in petrochemical and chemical enterprises, the site is liable to be polluted by high concentration of toxic organic matter. The volatilization or dissolution of toxic organic compounds will cause harm to the atmosphere, soil and groundwater around the site, so it is necessary to fix the pollutants quickly and prevent their spread and diffusion. Lime is a common solidified / stabilized base material used in hazardous waste treatment and remediation of contaminated sites, but when it is used to fix high concentrations of toxic organic matter, it mainly depends on microstructure encapsulation. Organic matter is volatile and dissolves, and its fixation ability is relatively weak. The surface of lime powder was modified to have hydrophobic and oil-hydrophobic properties, which could improve its ability to capture and immobilize specific toxic organic pollutants. It is of great significance for rapid solidification / stabilization of soil contaminated by high concentrations of toxic organic matter. In order to develop a rapid stabilizer for soil contaminated by high concentration toxic organic compounds, calcium oxide (CaO), the main mineral component of lime, was used as the base material, and stearic acid (Stearic Acid,SA) and silane coupling agent (KH570 (Silane Coupling Agent KH570,KH570) were selected as two modifiers in this paper. The surface hydrophobic modification of CaO powder was carried out by wet process. The effect of different process conditions on the modification effect was discussed. The morphology and structure of modified CaO were characterized. According to the contact angle index, the optimum technological conditions for the modification of CaO by stearic acid are as follows: the mass fraction of CaO is 5: SA, the modification temperature is 30 鈩，

本文編號(hào)：2234066