【摘要】：赤泥是氧化鋁工業(yè)排放的廢棄殘?jiān)?近年來隨著氧化鋁工業(yè)規(guī)模的不斷擴(kuò)大,赤泥的排放量也大幅度增加,如處理處置不當(dāng),不僅大量占用土地資源,還將可能對水、大氣和生態(tài)等環(huán)境造成嚴(yán)重威脅。赤泥的比表面積較大,表面礦物具有一定的活性,可制備為廉價(jià)吸附劑。有研究表明,經(jīng)活化改性后的赤泥可作為水中氮磷的吸附材料,但粉末狀赤泥材料存在吸附后溶液渾濁,難以過濾等缺點(diǎn),是限制赤泥在廢水處理中實(shí)現(xiàn)大規(guī)模應(yīng)用的瓶頸。本研究采用廣西拜耳法赤泥為基本原料,摻以廢玻璃粉等作為輔料,利用廢玻璃粉熔點(diǎn)低、熔融范圍寬、析晶能力強(qiáng)的特點(diǎn),通過燒結(jié)法在較低燒成溫度下制備赤泥基顆粒吸附劑(RG1*),采用正交實(shí)驗(yàn)和單因素實(shí)驗(yàn)對其最佳制備工藝進(jìn)行研究,運(yùn)用XRD、SEM、FTIR、BET、EDS等分析方法對其進(jìn)行結(jié)構(gòu)表征,并考察吸附劑對氮、磷的吸附性能。研究結(jié)論如下：(1)通過正交和單因素實(shí)驗(yàn),確定最佳赤泥基顆粒吸附劑(RG1*)制備工藝條件為：赤泥、廢玻璃粉、高嶺土和碳粉的摻量分別為80%、10%、5%和5%,燒結(jié)溫度為870℃,保溫10min。所制備的吸附劑比表面積為6.00m2·g-1,吸水率為14.83%,體積密度為1.33 g/cm3,顯氣孔率20.06%,耐酸性為79.86%,耐堿性為96.41%,抗粉化率為99.33%。赤泥基顆粒吸附劑在投加量為4g/L、pH值為5、溶液初始濃度為50mg/L、恒溫27℃吸附180min的條件下,對磷的吸附能力為4.82mg/g。(2)SEM表征結(jié)果顯示,赤泥基顆粒吸附劑表面氣孔結(jié)構(gòu)豐富,在870℃溫度燒結(jié)10min條件下,RG1*赤泥基顆粒以連通氣孔為主,RG2*和RG3*赤泥基顆粒則以閉氣孔為主。FTIR分析結(jié)果表明,燒結(jié)后的RG1*赤泥基顆粒表面生成大量的羥基基團(tuán),且存在Si-O-Si鍵,因此吸附劑能通過此類化學(xué)鍵與吸附質(zhì)發(fā)生結(jié)合,提高吸附能力。(3)在對氨氮的吸附實(shí)驗(yàn)中,RG1*用量在4g/L,溶液初始pH值為9,模擬磷溶液濃度為50mg/L時(shí),恒溫(27℃)吸附反應(yīng),RG1*對模擬廢水中氨氮的吸附在180min達(dá)到平衡,平衡吸附容量為0.825mg/g。(4)在對磷的吸附實(shí)驗(yàn)中,RG1*用量在6g/L,溶液初始pH值為6,模擬磷溶液濃度為50g/L時(shí),恒溫(27℃)吸附反應(yīng),240min后吸附基本達(dá)到平衡,平衡吸附容量為4.29mg/g。RG1*對磷的吸附等溫?cái)M合符合Freundlich等溫吸附模型,吸附動(dòng)力學(xué)過程符合偽二級(jí)動(dòng)力學(xué)模型和顆粒內(nèi)擴(kuò)散模型。通過EDS分析,赤泥中溶出的Al3+、Ca2+、Fe3+與磷發(fā)生了化學(xué)沉淀反應(yīng)；FTIR結(jié)果顯示,RG1*表面-OH基團(tuán)會(huì)與磷酸根進(jìn)行交換結(jié)合,將磷吸附在赤泥表面上。
[Abstract]:Red mud is the waste residue discharged from alumina industry. In recent years, with the continuous expansion of alumina industry, the discharge of red mud is also greatly increased. If the disposal is not proper, not only a large amount of land resources will be occupied, but also water may be affected. The environment, such as the atmosphere and ecology, poses a serious threat. The specific surface area of red mud is large and the surface minerals have certain activity, which can be prepared as cheap adsorbent. Some studies have shown that the activated red mud can be used as the adsorption material for nitrogen and phosphorus in water, but the powder red mud material has the disadvantages of turbidity of solution after adsorption and difficulty of filtration, which is the bottleneck to restrict the large-scale application of red mud in wastewater treatment. In this study, the red mud of Bayer process in Guangxi was used as the basic raw material, and the waste glass powder was mixed as the auxiliary material. The characteristics of the waste glass powder were low melting point, wide melting range and strong crystallization ability. Red mud based granular adsorbent (RG1*) was prepared by sintering method at lower sintering temperature. Orthogonal experiment and single factor experiment were used to study the optimum preparation process. XRD,SEM,FTIR,BET, was used to prepare the adsorbent. The structure of the adsorbent was characterized by EDS and the adsorption properties of the adsorbent for nitrogen and phosphorus were investigated. The results are as follows: (1) by orthogonal and single factor experiments, the optimum preparation conditions of red mud, waste glass powder, kaolin and carbon powder were determined as follows: the content of red mud, waste glass powder, kaolin and carbon powder were 80 1010% and 5%, respectively. The sintering temperature is 870 鈩，

本文編號(hào)：2400259