本文選題：砷 + 納米零價(jià)鐵��； 參考：《環(huán)境工程學(xué)報(bào)》2017年05期

【摘要】：金礦開采后的尾礦中含有大量的砷,納米零價(jià)鐵可以有效穩(wěn)定尾礦中的砷,但是在尾礦的后期復(fù)墾過程中,表層植被分泌的小分子有機(jī)酸,會(huì)使土壤中穩(wěn)定的砷重新釋放,造成二次污染。以植物根系分泌的常見小分子有機(jī)酸中的乙酸作為研究對(duì)象,在納米零價(jià)鐵(NZVI)去除砷的動(dòng)力學(xué)基礎(chǔ)上,利用批實(shí)驗(yàn)方法研究乙酸對(duì)穩(wěn)定砷的影響過程。結(jié)果表明,納米鐵可以在幾分鐘內(nèi)去除尾礦浸出液中的砷,反應(yīng)符合準(zhǔn)二級(jí)動(dòng)力學(xué)模型,鐵砷質(zhì)量比約500∶1時(shí),砷去除率可以達(dá)到94%以上。NZVI快速去除As(Ⅴ)主要是在NZVI表面的氧化鐵上發(fā)生吸附、共沉淀作用。有氧條件下的NZVI對(duì)As(Ⅴ)去除效果優(yōu)于無氧條件下的效果,長(zhǎng)期有氧腐蝕NZVI對(duì)浮選尾礦和生物氧化尾礦的砷去除率比未腐蝕的分別增加了18.03%和15.21%。乙酸鹽對(duì)長(zhǎng)期有氧腐蝕NZVI穩(wěn)定的浮選尾礦和生物氧化尾礦砷的解吸率比未腐蝕的分別減少了7.56%和20.01%。當(dāng)乙酸(以三水合乙酸鈉計(jì))與納米鐵的質(zhì)量比達(dá)到2.72∶1時(shí),由于乙酸的羧基與砷酸根有相似的電荷類型,可以與砷競(jìng)爭(zhēng)吸附鐵氧化物表面的吸附位點(diǎn),又可以與三價(jià)鐵離子形成穩(wěn)定的配合物,會(huì)使穩(wěn)定的砷重新釋放。但當(dāng)鐵砷質(zhì)量比逐漸增大(大于5 000∶1),較多的吸附位點(diǎn)會(huì)有效抑制乙酸鹽對(duì)砷的釋放。
[Abstract]:There is a large amount of arsenic in the tailings after gold mining, and nanocrystalline zero-valent iron can effectively stabilize the arsenic in the tailings, but during the late reclamation of the tailings, the small molecular organic acids secreted by the surface vegetation will release the stable arsenic from the soil. Cause secondary pollution. Acetic acid in common small organic acids exudated by plant roots was used as the research object. Based on the kinetics of removing arsenic from NZVI, the effects of acetic acid on arsenic stabilization were studied by batch experiment. The results show that nanocrystalline iron can remove arsenic from the tailings leachate in a few minutes. The reaction accords with the quasi-second-order kinetic model, and the mass ratio of iron to arsenic is about 500: 1. The removal rate of arsenic can reach more than 94%. NZVI can remove as (鈪，

本文編號(hào)：1916563