【作者】 王宜鑫；

【导师】 封克；

【作者基本信息】 扬州大学 ， 植物营养学， 2007， 硕士

【摘要】 本文以三种不同的粘土矿物为材料,研究了不同条件下它们对重金属离子的吸附效果,比较了它们的吸附差异性,探讨了不同粘土矿物材料对重金属离子的吸附特征,同时研究了Cu2+和Zn2+共存条件下,天然膨润土对其吸附效果及其影响因素,并比较了与其单独存在下的吸附差异性,以期为实际应用提供参考。通过研究膨润土对重金属离子不同吸附类型的吸附量及膨润土吸附重金属离子前后的结构变化,探讨了膨润土吸附重金属离子的有关机理,以期为更好地利用膨润土等粘土矿物材料处理重金属废水提供理论依据。同时,本实验首次利用羟基铬柱撑膨润土处理含Cr(Ⅵ)模拟废水,探讨了羟基铝、羟基铬柱撑膨润土对Cr(Ⅵ)的吸附效果,讨论其与原膨润土对Cr(Ⅵ)的吸附差异性,并且观察了羟基铝、羟基铬柱撑膨润土与原膨润土的X射线衍射特征变化,初步探讨了其吸附机理。研究的主要结果如下:(1)对于具有可膨胀层间的粘土矿物而言,其对目标重金属的吸附量不仅仅由单一的阳离子交换量所决定。就吸附特点而言,在一定的浓度范围内,所试三种矿物(膨润土、蛭石、沸石)对Cu2+、Zn2+、Cd2+和Pb2+的吸附均呈很好的直线关系。(2)重金属离子在矿物表面的吸附过程是个迅速的过程,矿物对重金属离子的吸附在10min内即可达最大值。粘土矿物不同颗粒细度对重金属离子的去除率有所不同,但并非颗粒越细吸附量越大。较高的pH(6左右)有助于粘土矿物对溶液中重金属离子的吸附,但考虑到实际操作的其它因素,不能把pH调得过高。(3)Cu2+、Zn2+共存条件下,膨润土对其吸附依然是迅速的过程,10min内即可达最大值。膨润土不同颗粒细度对Cu2+和Zn2+的吸附量变化与其单独存在条件下一致。较高的pH(6左右)仍然有助于膨润土对混合溶液中Cu2+的吸附,但对Zn2+的吸附较其单独存在下受pH的影响小。(4) Zn2+的存在对膨润土吸附Cu2+有一定影响,但膨润土吸附混合液中Zn2+的量大于Cu2+的吸附减少量。相对于Zn2+对膨润土吸附Cu2+的影响, Cu2+对膨润土吸附Zn2+的影响更大。(5)相同重金属摩尔浓度条件下,膨润土对Cu2+的吸附量稍高于Zn2+和Cd2+,但总体相差不大。即膨润土对重金属离子的吸附量主要由溶液中重金属离子的摩尔浓度决定的,而与重金属离子的种类关系不大。(6)膨润土对Cu2+的吸附基本上都是晶层吸附,而对Zn2+和Cd2+的吸附既存在表面吸附又存在晶层吸附。膨润土对Cu2+、Zn2+和Cd2+的晶层吸附量大小顺序依次为Cu2+ > Zn2+ > Cd2+。吸附Cu2+以后膨润土层间距加大,说明有一部分的Cu2+进入到了膨润土的层间。(7)除200℃热活化膨润土对Cu2+的吸附量较天然膨润土稍大外,400℃、600℃和800℃热活化膨润土对Cu2+的吸附量均比天然膨润土小。同时,不同热活化膨润土的d001值均低于天然膨润土,且其d001衍射峰明显向高角度偏移,衍射峰强度也低于天然膨润土。(8)不同体积分数硫酸活化后膨润土对Cu2+的吸附量均较天然膨润土有所降低。不同酸改性膨润土的d001衍射峰强度均低于天然膨润土,除20%硫酸活化土外,不同酸活化膨润土的d001值也均较天然膨润土小。(9)酸-钠化膨润土对Cu2+的吸附明显优于天然膨润土。膨润土经酸-钠改性后,其d001衍射峰明显发生偏移,衍射峰强度显著降低,d001值也由1.5301nm降至1.2571nm。(10)羟基铬柱撑膨润土对溶液中Cr(Ⅵ)的吸附显著好于羟基铝柱撑膨润土和原膨润土。羟基铬柱撑膨润土对Cr(Ⅵ)的吸附在30 min内即可达到吸附平衡。在溶液浓度为20mg L-1以下时,羟基铬柱撑膨润土对溶液中Cr(Ⅵ)的吸附量与溶液Cr(Ⅵ)浓度呈很好的直线关系,可用二元一次方程来表示:y=0.0199x-0.017,R2=0.9908。(11)溶液pH在4-10范围内时,羟基铬柱撑膨润土对溶液中Cr(Ⅵ)的吸附效果均很好,在pH为12时,其对Cr(Ⅵ)的吸附量明显降低;羟基铝柱撑膨润土对Cr(Ⅵ)的吸附受溶液pH的影响很小。更多还原

【Abstract】 In this paper, the adsorption effect of three kind of different clay minerals as a material to heavy metals was studied in different conditions. Compared with their adsorption difference, this article has discussed the different clay mineral material to the heavy metals adsorption characteristic, simultaneously has studied Cu2+ and under the Zn2+ coexistent condition, the natural bentonite to its adsorption effect and its the influence factor, and has compared if under the alone existence adsorption difference. And the adsorption quantity of different styles to heavy metals and the change of structure of bentonite fore-and-aft were studied in this paper. The related mechanism of adsorption to heavy metals on bentonite was discussed, as used clay mineral material handling heavy metals waste water well. At the same time, this experiment uses pillared bentonite processing using the hydroxyl-chromium to adsorb Cr (VI) for the first time. The adsorption effect of the hydroxy-aluminium and the hydroxyl-chromium bentonite to Cr (VI) has also discussed. And the X-ray diffraction characteristic change of the hydroxy-aluminium bentonite, the hydroxyl-chromium bentonite and the original bentonite was observed in this paper. Its adsorption mechanism has discussed initially. The results as follows:(1)The quantity of adsorption by expansibility clay mineral is not just decided by single CEC. Speaking of the adsorption characteristic, in the certain density scope, three kind of minerals to Cu2+, Zn2+, Cd2+ and the Pb2+ adsorption assumes the very good linear relation.(2)The adsorption of heavy metals on clay minerals surface is a rapid process, the maximal quantity of adsorption appears in ten minutes. The different granularity of clay minerals has different adsorption effects to heavy metals, but the quantity of adsorption is not changed by granularity of clay minerals all the while. The biggish pH value (about 6) of solution conduces to the adsorption of clay minerals to heavy metals, but the pH value can not be regulated too high considered to other factors of factual operation.(3)The adsorption of the coexistence of Cu2+ and Zn2+ on bentonite surface is also a rapid process, the maximal quantity of adsorption appears in ten minutes. The adsorption effect of different granularity bentonite to the coexistence of Cu2+ and Zn2+ was also consistent with their single exist. The biggish pH value of solution conduces to the adsorption of bentonite to them.(4)The adsorption of Cu2+ to the bentonite has a certain influence when Zn2+ existence, but in the bentonite adsorption intermixture the Zn2+ quantity is bigger than Cu2+. Compare with the influence of adsorbs Cu2+ to the bentonite by Zn2+, the influence of adsorbs Zn2+ to the bentonite by Cu2+ is bigger.(5)Under the same heavy metal molar density condition, the quantity of adsorption of bentonite slightly is higher than Zn2+ and Cd2+ to Cu2+, but the overall difference is not big. Namely the bentonite adsorption mainly determinated by heavy metal ion molar density in solution.(6)The adsorption of bentonite to the Cu2+ is the crystal level adsorption basically, but to Zn2+ and Cd2+ adsorption both existence surface adsorption and existence crystal level adsorption. The bentonite to Cu2+, Zn2+ and the Cd2+ crystal level adsorption size order is Cu2+ > Zn2+ > Cd2+. The bentonite level spacing enlarged when adsorbing Cu2+, it can be explained there had part of Cu2+ enter to the bentonite level.(7)Besides 200℃hot activation bentonite, the quantity of adsorption to Cu2+ is smaller than natural bentonite, such as 400℃, 600℃and 800℃hot activation bentonite. At the same time, the d001 values of different hot activation bentonites were lower than the natural bentonite, also its d001 diffraction peak obviously displacement to the high angle, the diffraction peak intensity also is lower than the natural bentonite.(8)The quantity of adsorption to Cu2+ of different acidification bentonites was lower than the natural bentonite. The diffraction peak intensity is lower than the natural bentonite, and the d001 values of different acidification bentonites were lower than the natural bentonite besides 20% sulfuric acidification bentonites.(9)The acid-sodium bentonite obviously surpasses the natural bentonite to the Cu2+ adsorption. The bentonite after the acid-sodium modification, its d001 diffraction peak obviously has the displacement, the diffraction peak intensity remarkably reduces, and the d001 value also falls by 1.5301 nm to 1.2571 nm.(10)The adsorption to Cr (VI) of the hydroxyl-chromium bentonite is better than the hydroxy-aluminiumcolumn bentonite and the original bentonite. The maximal quantity of adsorption on the hydroxyl-chromium bentonite appears in 30 minute. When the solution concentration is below 20 mg L-1, the quantity of adsorption to Cr (VI) on the hydroxyl-chromium bentonite is very good linear relation with solution Cr (VI), may use the dual first power regulation to indicate: y=0.0199x-0.017, R2=0.9908.(11)When the solution pH is in the scape of 4 to 10, the adsorption effect to Cr (VI) on hydroxyl-chromium bentonite is well.And when the solution pH is 12, the quantity of adsorption to Cr (VI) obviously reduces. The influence of solution pH of adsorption to Cr (VI) on the hydroxy-aluminium bentonite is small.更多还原