本文選題：重金屬 + Cu~(2+)��； 參考：《北京化工大學(xué)》2016年碩士論文

【摘要】：近年來(lái),隨著現(xiàn)代工業(yè)的快速發(fā)展,重金屬的開(kāi)采和應(yīng)用越來(lái)越廣泛,大量含重金屬的廢水沒(méi)有經(jīng)過(guò)達(dá)標(biāo)處理就排放到環(huán)境中,造成了巨大的安全隱患,直接威脅到人體健康和生態(tài)環(huán)境。因此,有效地處理重金屬?gòu)U水已成為當(dāng)今環(huán)保領(lǐng)域中一個(gè)亟待解決的重要問(wèn)題。傳統(tǒng)的處理工藝往往只能將重金屬?gòu)U水降低到一定濃度,不能將它們從水體中完全除去。而吸附法其材料來(lái)源廣,對(duì)低濃度的重金屬離子具有較高的去除能力,可以有效地達(dá)到排放標(biāo)準(zhǔn),是一種很有前途的重金屬?gòu)U水處理方法。常用的吸附劑是活性炭,但其價(jià)格偏貴,在應(yīng)用中受到限制。目前針對(duì)活性炭等較為昂貴的問(wèn)題,人們正在研制各種高效低廉的吸附劑。木屑是一種林業(yè)廢棄物,廉價(jià)易得,且產(chǎn)量巨大,由于它表面為多孔結(jié)構(gòu)且本身含羥基官能團(tuán),是一種應(yīng)用前景廣泛的重金屬吸附劑,但木屑吸附量不大,往往需要通過(guò)改性提高其吸附性能。本文用熱解+NaOH浸泡的方法制備改性木屑,并對(duì)其改性條件進(jìn)行優(yōu)化；采用表征手段觀察了改性前后木屑表面結(jié)構(gòu)的變化；通過(guò)間歇實(shí)驗(yàn),考察了pH、初始濃度、吸附時(shí)間、投加量、粒徑、離子強(qiáng)度等因素對(duì)改性木屑吸附Cu2+的影響；在相同條件下,將改性木屑對(duì)Cu2+的吸附效果與活性炭和原木屑進(jìn)行比較；并進(jìn)行吸附等溫線、吸附動(dòng)力學(xué)和熱力學(xué)參數(shù)研究,進(jìn)一步揭示木屑對(duì)重金屬離子的吸附過(guò)程,探討改性木屑吸附銅離子的機(jī)理。研究結(jié)果表明：木屑的最佳改性條件為：熱解條件(熱解溫度240℃、熱解時(shí)間45min)以及浸泡條件(NaOH溶液的浸泡時(shí)間3h、NaOH溶液的浸泡濃度0.4mol/L、NaOH溶液浸泡的浸漬比1：20)：與原始木屑相比,改性木屑的比表面積變大,表面相對(duì)平整光滑且出現(xiàn)了一些明顯的孔隙,羥基增多；對(duì)于初始濃度為20mg/L的銅離子溶液,在吸附時(shí)間為180min, pH為5,投加量為4g/L的最佳吸附條件下,改性木屑對(duì)Cu2+的去除率可以達(dá)到99%,處理后的Cu2+剩余濃度低于國(guó)家要求的廢水排放一級(jí)標(biāo)準(zhǔn)(0.5 mg/L)；與原木屑和活性炭相比,改性木屑的平衡時(shí)間縮短了60min,吸附速率提高了50%；改性木屑對(duì)銅離子的吸附符合Langmuir等溫模型,最大吸附量為31.25mg/g,是原始木屑吸附量的8倍,是活性炭的3倍,準(zhǔn)二級(jí)反應(yīng)動(dòng)力學(xué)模型能更好的描述改性木屑對(duì)銅離子吸附反應(yīng)的動(dòng)力學(xué)；改性木屑對(duì)Cu2+的去除是化學(xué)吸附和物理吸附共同作用的結(jié)果。
[Abstract]:In recent years, with the rapid development of modern industry, the mining and application of heavy metals is becoming more and more extensive. It is a direct threat to human health and ecological environment. Therefore, the effective treatment of heavy metal wastewater has become an important problem in the field of environmental protection. The traditional treatment process can only reduce the heavy metal wastewater to a certain concentration and can not completely remove them from the water. The adsorption method is a promising treatment method for heavy metal wastewater because of its wide source of materials, high removal capacity of heavy metal ions with low concentration, and can meet the discharge standard effectively. The commonly used adsorbent is activated carbon, but its price is too high, so it is limited in application. At present, for the more expensive problems such as activated carbon, people are developing various kinds of high-efficiency and low-cost adsorbents. Wood sawdust is a kind of forestry waste, which is cheap and easy to get, and its yield is huge. Because of its porous structure and hydroxyl functional group, it is a kind of heavy metal adsorbent with wide application prospect, but the adsorption amount of wood chips is not large. It is often necessary to improve the adsorption performance by modification. In this paper, the modified sawdust was prepared by the method of pyrolysis NaOH soaking, and the modification conditions were optimized. The changes of the surface structure of the wood chips before and after modification were observed by means of characterization, and the pH, initial concentration and adsorption time were investigated by intermittent experiments. The effects of adding amount, particle size and ionic strength on the adsorption of Cu _ 2 by modified wood scraps were studied. Under the same conditions, the adsorption effect of modified wood chips on Cu _ 2 was compared with that of activated carbon and raw wood chips, and the adsorption isotherm was carried out. The adsorption kinetics and thermodynamic parameters were studied to reveal the adsorption process of heavy metal ions and the mechanism of copper ion adsorption by modified sawdust. The results show that the optimum modification conditions of sawdust are pyrolysis conditions (pyrolysis temperature 240 鈩，

本文編號(hào)：2086204