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  本文選題：生物炭 + 六價鉻��； 參考：《中國地質(zhì)大學(北京)》2015年碩士論文

【摘要】：生物炭應用在土壤中具有溫室氣體減排、改善土壤性質(zhì)、豐富土壤微生物群落等作用,同時對污染物有較好吸附效果,能有效控制其遷移作用。本文著重考察生物炭對污染物的吸附能力,以六價鉻和莠去津作為目標污染物,研究生物炭在土壤環(huán)境中對六價鉻和莠去津的吸附鎖定效果,并將生物炭酸化來提高對莠去津的吸附能力,探討酸化后生物炭吸附能力提升的原因。本文通過土柱淋濾實驗,研究土壤中添加生物炭后對Cr(VI)的遷移影響,特別是對其進行模擬酸雨淋濾實驗,進一步研究含生物炭的土壤對Cr(VI)的鎖定效果。結(jié)果表明,僅施加1%的生物炭,就能大幅度提高土壤系統(tǒng)固定Cr(VI)的能力,小粒徑生物炭對Cr(VI)的吸附固定能力更加明顯,在一定條件下是大粒徑的固定吸附量的3倍,在酸雨淋濾作用下也不易解吸。關于酸化前后生物炭對莠去津的吸附效果實驗,實驗結(jié)論說明酸化能夠提高生物炭對莠去津的吸附能力。酸化前后的生物炭都可以用Freundlich方程進行擬合,溫度對吸附能力有顯著的影響,隨著溫度的升高,吸附量也隨之提高,酸化前生物炭符合Elovich動力學方程,而酸化后生物炭符合準二級動力學方程。酸化后的生物炭對莠去津具有更好的吸附能力,是由于酸化增加了生物炭的表面積和孔徑、孔容等,使得生物炭具有更多的吸附位點和更強的范德華力,同時也改變了生物炭的表面電性,與莠去津之間產(chǎn)生強烈的靜電吸引。將生物炭添加進土壤中,可以提高土壤系統(tǒng)對莠去津的吸附固定效果,隨著生物炭添加量的增加,吸附固定效果增加。在土壤培養(yǎng)試驗中,生物炭沒有出現(xiàn)解吸,表現(xiàn)了很好的吸附穩(wěn)定性。實驗證明土壤的含水量對酸化后的生物炭吸附莠去津的能力有明顯的影響,當土壤長期處于高含水量狀態(tài)時,酸化后生物炭的吸附能力有所下降。綜上所述,生物炭在土壤中對六價鉻、莠去津都有很好的吸附固定作用,可以有效的降低兩者的遷移性,特別是將生物炭酸化后,能夠更好的提升對莠去津的吸附能力,酸化后的生物炭在我國北方的旱田土壤中應用能夠達到比較好的吸附效果,實驗結(jié)果對不同類型的污染土壤治理有很好的實際參考價值。
[Abstract]:Biochar can reduce greenhouse gas emissions, improve soil properties, enrich soil microbial communities, and have good adsorption effect on pollutants, which can effectively control their migration. In this paper, the adsorption ability of biochar to pollutants was investigated. The adsorption and locking effect of biochar on hexavalent chromium and atrazine in soil environment was studied with hexavalent chromium and atrazine as the target pollutants. The adsorption ability of atrazine was improved by acidification of biochar, and the reason for the increase of adsorption ability of biochar after acidification was discussed. In this paper, the effects of biochar on Cr (VI) migration in soil were studied by soil column leaching experiment, especially the simulated acid rain leaching experiment, and the locking effect of biochar containing soil on Cr (VI) was further studied. The results showed that the ability of Cr (VI) fixation in soil system could be greatly improved by adding only 1% biochar. The adsorption and fixation capacity of small diameter biochar on Cr (VI) was more obvious than that of large diameter biochar under certain conditions, and the adsorption capacity of Cr (VI) was 3 times as much as that of large particle size. It is not easy to desorption under acid rain leaching. As to the adsorption effect of atrazine on biochar before and after acidification, the experimental results show that acidification can improve the adsorption ability of atrazine to biochar. The biochar before and after acidification can be fitted by Freundlich equation. Temperature has a significant effect on the adsorption capacity. With the increase of temperature, the adsorption capacity increases, and the biochar before acidification accords with Elovich kinetic equation. The acidified biochar accords with the quasi-second-order kinetic equation. The acidated biochar has better adsorption ability to atrazine because acidification increases the surface area, pore size and pore volume of biochar, which makes biochar have more adsorption sites and stronger van der Waals force. At the same time, it also changed the surface electrical properties of biochar, and produced strong electrostatic attraction between atrazine and biochar. The adsorption and fixation effect of atrazine could be improved by adding biochar into the soil, and with the increase of biochar addition, the adsorption and fixation effect of atrazine could be increased. In soil culture experiment, no desorption of biochar was observed, which showed good adsorption stability. The results showed that the soil moisture content had a significant effect on the adsorption ability of atrazine by acidified biochar, and when the soil was in high water content for a long time, the adsorption capacity of biochar decreased after acidification. To sum up, biochar has a good adsorption and fixation effect on hexavalent chromium and atrazine in soil, which can effectively reduce the migration of both, especially after acidification of biochar, it can improve the adsorption capacity of atrazine. The application of acidified biochar in dry soil of northern China can achieve better adsorption effect. The experimental results have a good practical reference value for the treatment of different types of contaminated soil.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X53

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相關期刊論文 前2條

1 王貴;張慶輝;程莉;同麗嘎;海全勝;;內(nèi)蒙古包頭市污灌區(qū)農(nóng)田土壤鉻的潛在生態(tài)風險評價[J];江蘇農(nóng)業(yè)科學;2012年07期

2 蒲維維;張小玲;徐敬;趙秀娟;徐曉峰;董t，

本文編號：2063421