铝锰氧化物负载锯末对砷、氟的吸附效能及机理
发布时间：2018-09-01 14:06
【摘要】：随着人们对健康和公共卫生的重视,饮用水中砷污染和氟超标问题越来越受到人们的关注。本研究以锯末为载体,通过负载铝锰氧化物改性锯末,制备改性锯末颗粒吸附剂。采用锯末作为吸附剂的载体,不仅能充分利用农业废弃物,也可以找到一个经济、环境友好的吸附材料。并对改性锯末表面特性、吸附去除氟、砷的效率及吸附机理进行了探讨。主要实验结果如下:1.在SEM、FTIR、BET、XPS等分析基础上,对改性锯末进行了表面结构研究。相比于原锯末,改性锯末在1055 cm-1处的(-OH)弯曲振动峰型更加凸显;改性锯末的表面有微粒聚集,比表面积从0.757 m2/g增加到34.04m2/g。经测定改性锯末含锰1.485mg/g,含铝40.864mg/g。2.通过投加量、pH实验可知,吸附剂的最佳投加量为1g/L;pH=3时吸附除F效果较差,这是因为pH=3时溶出大量的Al3+并与F-形成优势络合物[AlF]2+、[Al F2]+、AlF3,而此时吸附剂表面带正电荷(pHpzc=5.21);pH=3时吸附除As(III)、As(V)效果较好,改性锯末对As(III)的吸附是先将As(III)氧化成As(V)再吸附,和As(III)的吸附过程不同,改性锯末直接吸附As(V)。3.通过动力学实验,Power模型拟合R2值较高,可以很好的解释吸附F、As(III)、As(V)的动力学数据,说明改性锯末表面分布有不同吸附能的活性位点。吸附F、As(III)、As(V)的吸附速率受颗粒内扩散影响,但不是唯一的控制因素。4.通过等温实验,Freundlich、Langmuir等温线模型均能较好的描述改性锯末对F和As(III)的吸附,最大吸附量qm分别达到了27.68mg/g和29.95mg/g;Freundlich等温线模型可以很好的描述改性锯末吸附As(V),相比于原锯末,改性锯末对As(V)的吸附容量显著增大。5.共存阴离子实验结果可以看出,阴离子存在对吸附F有较小的负面影响;阴离子对吸附As(III)、As(V)也有负面影响,其中PO43-影响最大,因为PO43-和As为同族元素。6.动态除F的实验可以看出,穿透曲线受pH、填料层高度、进水流速及初始溶液浓度影响。从As(III)的穿透曲线可以看出,在初始浓度为100μg/L时,112h后达到了10μg/L;动态除As(V)的实验可以看出,初始浓度为150μg/L时,348h后达到了10μg/L,吸附去除As(V)持续不超过10μg/L的时间比去除As(III)时间长。
[Abstract]:With the attention of people to health and public sanitation, people pay more and more attention to arsenic pollution and fluorine excess in drinking water. In this study, the modified sawdust particle adsorbent was prepared by loading aluminum-manganese oxide on the carrier of sawdust. Using sawdust as the carrier of adsorbent can not only make full use of agricultural waste, but also find an economical and environmentally friendly adsorption material. The surface characteristics of modified sawdust, the adsorption efficiency of fluoride and arsenic and the adsorption mechanism were also discussed. The main experimental results are as follows: 1. The surface structure of modified sawdust was studied on the basis of SEM,FTIR,BET,XPS analysis. Compared with the original sawdust, the (-OH) bending vibration peak at 1055 cm-1 is more prominent, and the surface area of the modified sawdust increases from 0.757 m2 / g to 34.04 m2 / g, and the surface area of the modified sawdust is increased from 0.757 m2 / g to 34.04 m2 / g. The modified sawdust contains manganese 1.485 mg / g and aluminum 40.864 mg / g 路2. The results of pH experiment show that the optimum dosage of adsorbent is 1 g / L (pH = 3) and the adsorption efficiency of F is poor. This is because pH= 3 dissolves a large amount of Al3 and forms a dominant complex [AlF] 2, [Al F2] AlF3 with F-, and at this time, the adsorbent adsorbs As (III) as (V) with a positive charge (pHpzc=5.21) at pH = 3. The modified sawdust adsorbs As (III) by oxidizing As (III) to As (V) and then adsorbing it. Different from the adsorption process of As (III), modified sawdust adsorbs As (V). 3 directly. The kinetic data of adsorption of FBA as (III) and as (V) can be well explained by fitting the R ~ 2 value of the modified sawdust model with higher R ~ 2 value, indicating that the surface distribution of modified sawdust has active sites with different adsorption energy. The adsorption rate of (III) as (V) is affected by particle diffusion, but it is not the only controlling factor. 4. Freundlichl Langmuir isotherm model can well describe the adsorption of F and As (III) by modified sawdust. The maximum adsorption capacity of qm is up to 27.68mg/g and 29.95 mg / g / g Freundlich isotherm model, which can describe the adsorption of As (V), by modified sawdust as compared with that of original sawdust. The adsorption capacity of modified sawdust on As (V) was significantly increased. The experimental results of co-existing anions show that the existence of anions has a small negative effect on the adsorption of F, and that anions have a negative effect on the adsorption of As (III) and as (V), especially PO43-, because PO43- and As are homologous elements. The experimental results of dynamic removal of F show that the penetration curve is affected by the height of the pH, packing layer, the influent velocity and the initial concentration of the solution. From the breakthrough curve of As (III), we can see that 10 渭 g / L is achieved after 112h at the initial concentration of 100 渭 g / L and 10 渭 g / L after 348h when the initial concentration is 150 渭 g / L, and the time of As (V) removal is longer than that of As (III) removal.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ424;X703
本文编号：2217433
[Abstract]:With the attention of people to health and public sanitation, people pay more and more attention to arsenic pollution and fluorine excess in drinking water. In this study, the modified sawdust particle adsorbent was prepared by loading aluminum-manganese oxide on the carrier of sawdust. Using sawdust as the carrier of adsorbent can not only make full use of agricultural waste, but also find an economical and environmentally friendly adsorption material. The surface characteristics of modified sawdust, the adsorption efficiency of fluoride and arsenic and the adsorption mechanism were also discussed. The main experimental results are as follows: 1. The surface structure of modified sawdust was studied on the basis of SEM,FTIR,BET,XPS analysis. Compared with the original sawdust, the (-OH) bending vibration peak at 1055 cm-1 is more prominent, and the surface area of the modified sawdust increases from 0.757 m2 / g to 34.04 m2 / g, and the surface area of the modified sawdust is increased from 0.757 m2 / g to 34.04 m2 / g. The modified sawdust contains manganese 1.485 mg / g and aluminum 40.864 mg / g 路2. The results of pH experiment show that the optimum dosage of adsorbent is 1 g / L (pH = 3) and the adsorption efficiency of F is poor. This is because pH= 3 dissolves a large amount of Al3 and forms a dominant complex [AlF] 2, [Al F2] AlF3 with F-, and at this time, the adsorbent adsorbs As (III) as (V) with a positive charge (pHpzc=5.21) at pH = 3. The modified sawdust adsorbs As (III) by oxidizing As (III) to As (V) and then adsorbing it. Different from the adsorption process of As (III), modified sawdust adsorbs As (V). 3 directly. The kinetic data of adsorption of FBA as (III) and as (V) can be well explained by fitting the R ~ 2 value of the modified sawdust model with higher R ~ 2 value, indicating that the surface distribution of modified sawdust has active sites with different adsorption energy. The adsorption rate of (III) as (V) is affected by particle diffusion, but it is not the only controlling factor. 4. Freundlichl Langmuir isotherm model can well describe the adsorption of F and As (III) by modified sawdust. The maximum adsorption capacity of qm is up to 27.68mg/g and 29.95 mg / g / g Freundlich isotherm model, which can describe the adsorption of As (V), by modified sawdust as compared with that of original sawdust. The adsorption capacity of modified sawdust on As (V) was significantly increased. The experimental results of co-existing anions show that the existence of anions has a small negative effect on the adsorption of F, and that anions have a negative effect on the adsorption of As (III) and as (V), especially PO43-, because PO43- and As are homologous elements. The experimental results of dynamic removal of F show that the penetration curve is affected by the height of the pH, packing layer, the influent velocity and the initial concentration of the solution. From the breakthrough curve of As (III), we can see that 10 渭 g / L is achieved after 112h at the initial concentration of 100 渭 g / L and 10 渭 g / L after 348h when the initial concentration is 150 渭 g / L, and the time of As (V) removal is longer than that of As (III) removal.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ424;X703
【共引文献】
相关期刊论文 前1条
1 万祥云;朱泮民;;颗粒状污泥活性炭流化床吸附处理含铜矿山废水[J];化工环保;2013年04期
，本文编号：2217433
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