粘土矿物材料对水体中砷和重金属的控制研究

发布时间：2018-01-22 23:43

  本文关键词： 海泡石 凹凸棒 吸附 饱和吸附量 BCR形态　出处：《南京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着工农业的发展,我国土壤、河流和湖泊不同程度的存在砷和重金属污染,频发的砷中毒和重金属污染事件受到广泛关注,同时也强调了砷和重金属污染治理的迫切性。本文利用环境矿物材料的吸附性处理这类污染。砷污染研究的是海泡石和凹凸棒两种粘土矿物经过改性后对水体中As3+、As5+的吸附效果,并进行实验室模拟实验确定两种材料对As3+、As5+的饱和吸附量和反应平衡时间以及水环境的各种因素如pH、粒径、阴离子(硫酸根、碳酸根、磷酸根)对吸附效果的影响,通过动态收集装置模拟动态吸附过程。重金属研究分为水相吸附和沉积物固相固定,水相的吸附研究了两种材料对Pb2+和Cd2+的饱和吸附量、吸附平衡时间和pH的影响,沉积物固相的研究包括材料对沉积物pH的影响以及对Pb2+和Cd2+BCR形态的改变。试验结果表明未经改性的海泡石和凹凸棒对As3+、As5+的吸附效果较差,而经过800℃热改性的海泡石和700℃热改性的凹凸棒对As3+、As5+表现出极佳的效果,海泡石对As3+、As5+饱和吸附量分别为27.9mg/g、33.6mg/g,吸附平衡时间分别为4小时和1小时；凹凸棒对两者的饱和吸附量分别为68.26mg/g、31.84mg/g,吸附平衡时间分别为24小时和4小时。各因素影响为pH越高,海泡石和凹凸棒对As3+、As5+的吸附效果越好,粒径影响较小,硫酸根和碳酸根对As3+的吸附影响较大,对As5+影响较小,磷酸根基本没有影响,动态吸附效果较差。在pH为6和6.5时,采用原状海泡石和凹凸棒对Pb2+、Cd2+进行吸附效果较佳,海泡石对Pb2+、Cd2+的饱和吸附量为27.12mg/g、25.93mg/g,吸附平衡时间较长,均为24小时；凹凸棒对Pb2+、Cd2+的饱和吸附量为26.75mg/g、 24.55mg/g,吸附平衡时间在24以上。海泡石和凹凸棒的加入使沉积物的pH略有下降,海泡石降低了沉积物中弱酸提取态、可还原态的Pb,降低了弱酸提取态的Cd,对可氧化态的Pb、可还原态的Cd略有提高,凹凸棒对沉积物的影响规律与海泡石类似。
[Abstract]:In recent years, with the development of industry and agriculture, arsenic and heavy metal pollution in soils, rivers and lakes in China has been paid more and more attention. At the same time, the urgency of arsenic and heavy metal pollution treatment was emphasized. In this paper, the adsorptive property of environmental mineral materials was used to treat this kind of pollution. Arsenic pollution is studied by using two kinds of clay minerals, sepiolite and attapulgite, which have been modified to the water body. As3. . The adsorption effect of As5, and laboratory simulation experiments were carried out to determine the saturated adsorption capacity and reaction equilibrium time of the two materials to As3 as well as various factors of water environment such as pH, particle size. The influence of anions (sulphate, carbonate, phosphate) on adsorption effect was simulated by dynamic collecting device. Heavy metal adsorption was divided into water adsorption and sediment solid fixation. The effects of two kinds of materials on the saturated adsorption capacity, adsorption equilibrium time and pH of Pb2 and Cd2 were studied. The study of sediment solid phase includes the influence of the material on the pH of sediment and the change of Pb2 and Cd2 BCR morphology. The results show that the unmodified sepiolite and attapulgite have effect on As3. The adsorption effect of As5 was poor, but the sepiolite modified at 800 鈩，

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