本文關(guān)鍵詞：表面改性活性炭對(duì)鉻污染土壤的穩(wěn)定化研究　出處：《武漢科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 鉻污染土壤 活性炭 表面改性 穩(wěn)定

【摘要】：隨著工農(nóng)業(yè)的快速發(fā)展,土壤中重金屬污染日趨嚴(yán)重,其中鉻元素存在形式復(fù)雜,六價(jià)鉻離子毒性較強(qiáng)且容易遷移,已對(duì)生態(tài)環(huán)境造成嚴(yán)重威脅。在多種針對(duì)重金屬污染土壤修復(fù)方法中,穩(wěn)定/固化技術(shù)由于具有經(jīng)濟(jì)有效,適用范圍廣,操作簡單等優(yōu)勢,已廣泛用于底泥、淤泥、工業(yè)廢渣和尾礦中重金屬的穩(wěn)定與重金屬污染土壤的修復(fù),但尋求經(jīng)濟(jì)高效穩(wěn)定劑是穩(wěn)定技術(shù)的關(guān)鍵�；钚蕴坑捎谄渚哂胸S富的孔隙結(jié)構(gòu)與發(fā)達(dá)的比表面積且化學(xué)性質(zhì)穩(wěn)定,已廣泛用于含有重金屬氣體體系及液相體系的吸附,而用于固相體系的研究較少。本論文將研究活性炭進(jìn)行多種改性增強(qiáng)表面化學(xué)性質(zhì),用于鉻污染土壤的修復(fù),并探討改性活性炭對(duì)污染土壤中鉻的穩(wěn)定機(jī)理。本文首先以商品活性炭(標(biāo)記為AC)為原料,進(jìn)行硝酸、氨氣及賦硫改性分別制得含O、N和S官能團(tuán)的活性炭(分別標(biāo)記為OAC、NAC及SAC),并用BET、元素分析、FT-IR、Raman、XPS、Boehm滴定及pHpzc手段表征其理化性質(zhì)。結(jié)果顯示,OAC比表面積增加了27.0%,表面氧含量明顯增加,C=O含量有所降低,生成了COOH,OH等含氧官能團(tuán);NAC比表面積增加了20.2%,表面引入含氮官能團(tuán),如吡啶、吡咯及吡啶氧化物等,活性炭堿性增強(qiáng);SAC的比表面積下降了34.6%,改性過程中形成了-S-S-,噻吩,砜,O=S=O等含硫官能團(tuán)。利用BCR連續(xù)浸提法考察了改性活性炭對(duì)鉻鹽廠區(qū)不同水平及垂直分布污染土壤中鉻賦存形態(tài)的影響,探討活性炭對(duì)污染土壤中鉻的穩(wěn)定作用。在可交換態(tài)總鉻含量為2.41%~39.88%的供試土壤中,分別添加5%(w%)AC,OAC,NAC及SAC后,可交換態(tài)總鉻與六價(jià)鉻含量均有不同程度的下降,其中最優(yōu)穩(wěn)定效果試樣中六價(jià)鉻降低到未檢出線,四種活性炭穩(wěn)定總鉻與六價(jià)鉻的能力依次為SACOACACNAC。為了進(jìn)一步研究活性炭對(duì)土壤中鉻生物有效性的影響,向土壤中添加OAC與NBC(氨氣改性生物炭),以辣椒為指示作物進(jìn)行盆栽實(shí)驗(yàn),觀察生長狀況,分析不同器官鉻離子含量,發(fā)現(xiàn)OAC有效降低了土壤中鉻離子的生物有效性及遷移能力,減少對(duì)辣椒的毒害作用,在鉻離子濃度為300mg/kg的土壤中,鉻在不同器官的富集程度呈現(xiàn)根葉莖果實(shí)的趨勢,90%的鉻富集在植株根部。研究了上述四種活性炭對(duì)Cr(VI)與Cr(III)的等溫吸附及吸附動(dòng)力學(xué)過程。結(jié)果表明,Langmuir模型比較吻合AC吸附Cr(VI)與Cr(III)的過程;由于表面改性增加的官能團(tuán)使OAC、NAC及SAC表面不均勻,Freundlich模型對(duì)Cr(VI)與Cr(III)的等溫吸附過程擬合效果更好。AC、OAC、NAC及SAC吸附Cr(VI)與Cr(III)動(dòng)力學(xué)過程符合擬二級(jí)動(dòng)力學(xué)方程,表明吸附Cr(VI)與Cr(III)是化學(xué)吸附過程。三種改性活性炭OAC,NAC和SAC對(duì)Cr(VI)的飽和吸附量qe,exp均較AC有較大幅度的增加,在298K下,OAC,NAC及SAC對(duì)鉻離子的飽和吸附量分別增加了112.17%,120.73%和55.20%。結(jié)合FT-IR、Raman和XPS表面分析技術(shù)對(duì)吸附Cr(VI)與Cr(III)前后的活性炭進(jìn)行表面性質(zhì)分析,發(fā)現(xiàn)表面改性過程中引入活性炭表面的多種官能團(tuán)(C=O,C-O-C,C-O或者O-S,吡啶,S-S,噻吩,O=S=O)均參與吸附過程,強(qiáng)化了化學(xué)吸附在吸附過程中的作用。
[Abstract]:With the rapid development of industry and agriculture, soil heavy metal pollution is becoming more and more serious, which exists in the form of chromium complex, six chromium ion toxicity is strong and easy to move, has caused a serious threat to the ecological environment. In a variety of the heavy metal contaminated soil remediation method, stable / solid technology because it is economical and effective, applicable to a wide range of operation simple and other advantages, has been widely used in the sediment, silt, repair and stabilization of heavy metal industrial waste residue and tailings in soil contaminated with heavy metals, but seek economic efficient stabilizer is key to stabilizing technology. Activated carbon due to its pore structure and developed specific surface area and stable chemical property rich, has been widely used for the adsorption of heavy metal containing gas system and liquid system, and used to study the solid system is less. This paper will study a variety of modified activated carbon enhanced surface chemical properties, for Remediation of chromium contaminated soil, and discusses the stability mechanism of modified activated carbon on pollution of chromium in soil. In this paper, commercial activated carbon (labeled AC) as raw materials, nitrate, ammonia and sulphur modification were prepared with O, N and S activated carbon functional groups (labeled OAC, NAC and SAC), and by BET, elemental analysis, FT-IR, Raman, XPS, Boehm and pHpzc characterization of titration means its physicochemical properties. The results showed that OAC increased by 27% than the surface area, surface oxygen content increased, C=O content decreased, the formation of COOH, OH and other oxygen-containing functional groups; NAC increased by 20.2% the specific surface area, surface into nitrogen containing functional groups such as pyridine, pyrrole and pyridine oxide, activated carbon enhanced alkaline; the specific surface area of SAC decreased by 34.6%, modified during the formation of -S-S-, thiophene, sulfone, O=S=O and sulfur functional groups. Use of BCR continuous extraction was investigated on different modified activated carbon chromate water Effect of chromium speciation in horizontal and vertical distribution of contaminated soil, the effect of activated carbon stable effect on the pollution of chromium in soil. The exchangeable chromium content of 2.41%~39.88% tested soils were added 5% (w%) AC, OAC, NAC and SAC, exchangeable chromium and chromium six. The content decreased to a certain degree, the stability effect of optimal six sample chromium reduced to unghecded qualify, ability of four kinds of activated carbon and stable total chromium chromium six followed by SACOACACNAC. in order to further study the effect of active carbon on the bioavailability of chromium in soil, add OAC and NBC to the soil (ammonia modified biochar), with pepper as the indicator plant pot experiment, observe the growth status, analysis of different organs of chromium ion content, found that OAC effectively reduces the chromium ions in the soil biological validity and migration ability, reduce the toxicity of chromium ion concentration in pepper. 涓，

本文編號(hào)：1402767