赤泥基颗粒吸附剂的制备及其对水中氮磷的吸附研究
发布时间：2019-01-04 12:00
【摘要】：赤泥是氧化铝工业排放的废弃残渣,近年来随着氧化铝工业规模的不断扩大,赤泥的排放量也大幅度增加,如处理处置不当,不仅大量占用土地资源,还将可能对水、大气和生态等环境造成严重威胁。赤泥的比表面积较大,表面矿物具有一定的活性,可制备为廉价吸附剂。有研究表明,经活化改性后的赤泥可作为水中氮磷的吸附材料,但粉末状赤泥材料存在吸附后溶液浑浊,难以过滤等缺点,是限制赤泥在废水处理中实现大规模应用的瓶颈。本研究采用广西拜耳法赤泥为基本原料,掺以废玻璃粉等作为辅料,利用废玻璃粉熔点低、熔融范围宽、析晶能力强的特点,通过烧结法在较低烧成温度下制备赤泥基颗粒吸附剂(RG1*),采用正交实验和单因素实验对其最佳制备工艺进行研究,运用XRD、SEM、FTIR、BET、EDS等分析方法对其进行结构表征,并考察吸附剂对氮、磷的吸附性能。研究结论如下：(1)通过正交和单因素实验,确定最佳赤泥基颗粒吸附剂(RG1*)制备工艺条件为：赤泥、废玻璃粉、高岭土和碳粉的掺量分别为80%、10%、5%和5%,烧结温度为870℃,保温10min。所制备的吸附剂比表面积为6.00m2·g-1,吸水率为14.83%,体积密度为1.33 g/cm3,显气孔率20.06%,耐酸性为79.86%,耐碱性为96.41%,抗粉化率为99.33%。赤泥基颗粒吸附剂在投加量为4g/L、pH值为5、溶液初始浓度为50mg/L、恒温27℃吸附180min的条件下,对磷的吸附能力为4.82mg/g。(2)SEM表征结果显示,赤泥基颗粒吸附剂表面气孔结构丰富,在870℃温度烧结10min条件下,RG1*赤泥基颗粒以连通气孔为主,RG2*和RG3*赤泥基颗粒则以闭气孔为主。FTIR分析结果表明,烧结后的RG1*赤泥基颗粒表面生成大量的羟基基团,且存在Si-O-Si键,因此吸附剂能通过此类化学键与吸附质发生结合,提高吸附能力。(3)在对氨氮的吸附实验中,RG1*用量在4g/L,溶液初始pH值为9,模拟磷溶液浓度为50mg/L时,恒温(27℃)吸附反应,RG1*对模拟废水中氨氮的吸附在180min达到平衡,平衡吸附容量为0.825mg/g。(4)在对磷的吸附实验中,RG1*用量在6g/L,溶液初始pH值为6,模拟磷溶液浓度为50g/L时,恒温(27℃)吸附反应,240min后吸附基本达到平衡,平衡吸附容量为4.29mg/g。RG1*对磷的吸附等温拟合符合Freundlich等温吸附模型,吸附动力学过程符合伪二级动力学模型和颗粒内扩散模型。通过EDS分析,赤泥中溶出的Al3+、Ca2+、Fe3+与磷发生了化学沉淀反应；FTIR结果显示,RG1*表面-OH基团会与磷酸根进行交换结合,将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，
本文编号：2400259
[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，
本文编号：2400259
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