【摘要】：近年來(lái),有不少利用生物炭作為一種新型的吸附材料去除各種重金屬污染土壤和水體方面的研究,但針對(duì)含砷廢水的生物炭去除研究還鮮有報(bào)道。本研究以谷殼為原料,通過(guò)不同溫度缺氧高溫?zé)峤庵苽涑?種炭化谷殼,并通過(guò)酸、堿改性后篩選出吸附效果最好的一種炭化谷殼,將其進(jìn)行磁性負(fù)載,獲得另一種新型的負(fù)載納米Fe3O4的炭化谷殼(CRH-I)。研究CRH-I的吸附時(shí)間、pH、添加量這三個(gè)因素對(duì)吸附的影響；通過(guò)吸附動(dòng)力學(xué)、等溫吸附探討其吸附特性。同時(shí),了解CRH-I吸附解吸能力和針對(duì)實(shí)際含砷廢水去除能力。從BET比表面積、孔徑結(jié)構(gòu)分析、SEM、XRD、FTIR幾個(gè)方面對(duì)CRH-I進(jìn)行表征分析及機(jī)理研究。主要研究結(jié)果如下：(1)通過(guò)對(duì)As(Ⅴ)吸附性能篩選結(jié)果可知,CaO改性的炭化谷殼,使得炭化谷殼得到了活化,溶液中As(Ⅴ)去除率比較高。CRHCaO600的吸附效果最佳,去除率最高達(dá)到82%。將篩選出的CRHCaO600進(jìn)行磁性負(fù)載,成功合成新型炭化谷殼CRH-I。(2)吸附實(shí)驗(yàn)表明,剛開(kāi)始吸附速率較快,隨著時(shí)間推移,速率逐漸下降,8h時(shí),CRH-I對(duì)As(Ⅴ)吸附已幾乎達(dá)到飽和狀態(tài),吸附達(dá)到平衡。相對(duì)CRHCaO600而言,CRH-I對(duì)As(Ⅴ)的去除率明顯提高。隨著溶液pH值降低,CRH-I對(duì)As(Ⅴ)的去除率逐漸升高,pH=2時(shí)的去除率高達(dá)98.3%；當(dāng)pH=11時(shí),去除率只有63.7%。CRH-I吸附反應(yīng)滿足準(zhǔn)動(dòng)力學(xué)二級(jí)方程,相關(guān)系數(shù)為R2=0.999；在不同溫度下,將CRH-I對(duì)As(Ⅴ)的吸附驗(yàn)數(shù)據(jù)進(jìn)行Langmuir方程和Freundlich等溫方程擬合,結(jié)果更符合Langmuir方程；在25℃時(shí),相關(guān)系數(shù)R2=0.985。通過(guò)吸附熱力學(xué)分析表明,該吸附過(guò)程是自發(fā)進(jìn)行的,且低溫更有利于吸附的進(jìn)行。(3)通過(guò)吸附解吸實(shí)驗(yàn)可以得知,5次吸附解吸的去除率分別為83.2%、66.4%、65.6%、67.2%、64.0%。由此可以看出,第一次吸附解吸后CRH-I對(duì)As(Ⅴ)的去除率仍然是很高的,從第二次以后CRH-I對(duì)As(Ⅴ)的去除率開(kāi)始降低,但是保持一個(gè)較穩(wěn)定的去除率,說(shuō)明CRH-I依然具備良好的吸附性能,且再生吸附性能穩(wěn)定。(4)經(jīng)過(guò)對(duì)比表面積進(jìn)行表征分析發(fā)現(xiàn),CRH-I相較CRH600的BET比表面積增大約30%,達(dá)到182m2·g-1,微比表面積和微孔體積都擴(kuò)大了6倍左右。XRD檢測(cè)結(jié)果可知,吸附過(guò)程沒(méi)有新的晶體產(chǎn)生,CRH-Ⅰ吸附As(V)為表面吸附。FTIR分析結(jié)果表明,相比CRH600,CRH-Ⅰ分子間的羧基和酚羥基官能團(tuán)有所增加,產(chǎn)生了芳構(gòu)化反應(yīng)和脂肪醚類物質(zhì)。(5)通過(guò)對(duì)實(shí)際廢水進(jìn)行預(yù)處理和添加CRH-Ⅰ相結(jié)合的處理方法,在CRH-Ⅰ添加量為2 g、固液比為1：200時(shí),出水As(Ⅲ)、As(V)濃度分別為0.034、0.245mg·L-1,都達(dá)到了國(guó)家污水綜合排放標(biāo)準(zhǔn)(GB8978-1996)中所規(guī)定的要求(砷最高允許排放濃度0.5 mg·L-1)。Pb、Cd、Zn、Mn的去除率隨著CRH-Ⅰ添加量的增加而逐漸上升,去除率分別為9.8%-30.7%、34.1%-55.1%、10.9%-22.8%、57.1%-66.7%。其中Pb、Cu也達(dá)到了排放標(biāo)準(zhǔn)。
[Abstract]:In recent years, biochar has been used as a new adsorption material to remove various heavy metals from contaminated soil and water. However, there are few reports on the removal of arsenic wastewater. In this study, five kinds of carbonized husks were prepared by pyrolysis at different temperature, anoxia and high temperature. After modified with acid and alkali, a carbonized husk with the best adsorption effect was selected and loaded with magnetic. Another new carbonized grain husk (CRH-I) loaded with nanometer Fe3O4 was obtained. The effects of adsorption time and pH, addition on the adsorption of CRH-I were studied, and the adsorption characteristics were investigated by adsorption kinetics and isothermal adsorption. At the same time, the adsorption and desorption ability of CRH-I and the removal ability of arsenic-containing wastewater were studied. The characterization and mechanism of CRH-I were studied from the aspects of BET surface area, pore size structure analysis and SEM,XRD,FTIR. The main results are as follows: (1) the results of screening the adsorption properties of As (鈪，

本文編號(hào)：2414892