【作者】 吕志江；

【导师】 刘云国；

【作者基本信息】 湖南大学 ， 环境科学与工程， 2008， 硕士

【摘要】 重金属是常见的环境污染物,主要来源采矿、冶金、化工、电镀、皮革等工业排放的废水和固体垃圾填埋厂的滤液。重金属主要通过食物链进入人体并在人体内积累,产生很强的污染生态效应。对重金属废水的处理,以及对其中有用金属的回收一直以来都是研究领域的研究热点。粉煤灰应用于废水处理,具有操作简便、效果好、成本低廉等优势。改性处理能大大提高粉煤灰的吸附性能,并能有效吸附水溶液中的重金属离子。本课题第一步对粉煤灰的改性进行了研究,实验结果表明,粉煤灰经1 mol/L盐酸和1 mol/L硫酸的混合酸在80℃下浸泡60 min,其中盐酸、硫酸体积比为1:3,粉煤灰与酸的固液比为1/8 （g/mL）,在浸泡过程中加入铁粉0.2 g/L,氯化钠0.3 g/L,得到去除效果好的改性粉煤灰。课题第二步,用第一步制成的粉煤灰为主要原料,对模拟含Cd²⁺、Pb²⁺、Cu²⁺的废水进行了实验,实验结果表明,废水中Cd²⁺、Pb²⁺、Cu²⁺的初始浓度、粉煤灰用量、pH值、吸附时间等因素均能影响粉煤灰对Cd²⁺、Pb²⁺、Cu²⁺的吸附效果。在Cd²⁺、Pb²⁺、Cu²⁺初始浓度均为40 mg/L,pH=7,搅拌2 h,粉煤灰的投加量分别为14、10、12 g/L的条件下,Cd²⁺、Pb²⁺、Cu²⁺的去除率分别达到96.53 %、99.21%、97.49 %。粉煤灰对Cd²⁺、Pb²⁺、Cu²⁺的吸附等温线符合Freundilich和Langmuir两种模式。课题第三步是对第二步的进一步研究,在多元重金属离子混合体系吸附实验中,发现当Pb²⁺与其他两种金属离子分别混合后,有利于其余两种重金属离子的去除,而当Cd²⁺作为干扰离子加入Cu²⁺的溶液中或将Cu²⁺作为干扰离子加入Cd²⁺的溶液中,粉煤灰对以上两种金属离子的去除率均降低,说明Cu²⁺、Cd²⁺混合时会互相干扰,影响吸附效果。更多还原

【Abstract】 Many industry including metals finishing, planting and mining acidic bring waste water containing cadmium, lead, copper, et al. Long-term ingestion of water containing higher concentration of heavy metals can cause many diseases such as stomach ailment, metal retardation, liver and kidney damage. Research in heavy metals removal and recovery are always a key problem in environmental protection. Fly ash has lots of advantages in the treatment of wastewater, such as simple process, high efficiency and low cost. Modification of Fly ash can improve its adsorption ability greatly and so makes it adsorb the contaminants such as heavy metal ions in wastewater more effectively.The first step of the issue in the modification of fly ash have been studied, the experimental results showed that the fly ash by 1 mol/L hydrochloric acid and 1 mol/L acid mixture of sulphuric acid at 80℃soak 60 min, including hydrochloric acid, sulfuric acid volume ratio To 1:3, fly ash and acid ratio of solid to liquid to 1/8 （g/mL）, immersion in the process of accession to iron 0.2 g/L, sodium chloride 0.3 g/L, by removal good Modification of fly ash.Improved fly ash was used to remove Cd²⁺, Pb²⁺, Cu²⁺ from simulated wastewater. The experiment results show that the adsorption capability was affected by the initial concentration of Cd²⁺, Pb²⁺, Cu²⁺, pH,adsorption time and the concentration of fly ash .The result also demonstrated that the remove rate of Cd²⁺,Pb²⁺,Cu²⁺ could reach 96.53%,99.21%,97.49%,within 2 hours at the solid/liquid ratio of 14,10,12 g?L-1, pH=7, when Cd²⁺, Pb²⁺, Cu²⁺ concentration at 40mg?L-1. Simulation to the adsorption process showed that the process could be fitted well by both Freundilich and Langmuir Equation.The third step is subject to the second step of further study, the heavy metal ions in the mixed system of multi-absorption tests, found that when Pb²⁺ metal ions and the other two were mixed, the remaining two is conducive to the removal of heavy metal ions, and when Cd²⁺as interference by adding Cu²⁺ ions in the solution or as an interference Cu²⁺ or Cd²⁺adding the solution of these two kinds of fly ash on the removal of metal ions are reduced, that Cu²⁺, Cd²⁺ mixed at each other Interference and impact the effect of the absorption.更多还原