钢渣处理含铅、镉废水的性能研究

发布时间：2018-05-19 18:00

本文选题：钢渣 + 铅离子　；参考：《南京理工大学》2015年硕士论文

【摘要】：吸附法以其设备简单、去除效率高和易操作等优点成为了目前处理水中重金属污染物最为广泛使用的方法之一,而寻找一种吸附性能好、价格低廉的吸附剂是吸附法应用的关键。钢渣作为炼钢过程中产生的一种固体废弃物,具有较大比表面积和多孔结构,是一种良好的吸附剂。基于上述观点,本文选择钢渣作为吸附剂,研究了其对水中铅离子和镉离子的吸附去除特征。实验利用化学成分分析仪、XRD、BET、SEM等表征手段对钢渣的化学成分、性质和结构特征进行分析,结果表明钢渣的主要成分为CaO,溶于水中呈碱性,对铅离子和镉离子具有一定的化学沉淀作用；观察钢渣的外貌发现,钢渣表面粗糙多孔,有利于吸附水中重金属离子。通过单一离子静态吸附实验,对钢渣的投加量、溶液初始pH、反应温度以及反应时间对吸附效果的影响进行了研究,结果表明钢渣投加量和反应时间对去除效果有较大影响,钢渣最佳质量投加比分别为铅/钢渣=1：10和镉/钢渣=1：20；初始pH值和温度对钢渣吸附重金属离子的影响不大,钢渣能够很好地适应废水的变化。实验还对钢渣去除重金属离子的机理进行了研究：通过观察实验现象及XRD、SEM分析表征,可知吸附和化学沉淀作用是钢渣去除铅离子和镉离子的主要机制。通过研究吸附机理可知,准二级动力学模型和Langmuir模型能更好的描述钢渣吸附铅离子和镉离子的过程,钢渣对水中铅离子和镉离子的吸附速率由化学吸附机制控制,其吸附形式为单层吸附。动态吸附实验结果表明,穿透时间随床层高度的增加而增加,但是随进水流速和进水初始浓度的增加而减少。动态吸附过程符合Thomas方程,相关系数R2值均在0.9以上,运用该方程可准确预测吸附柱的操作参数。通过计算结果可知,钢渣吸附柱对铅离子和镉离子的最大吸附量分别为69.86 mg/g和55.14 mg/g；动态竞争吸附实验结果还表明钢渣对铅离子和镉离子的吸附优先顺序为Pb2+Cd2+。
[Abstract]:Because of its simple equipment, high removal efficiency and easy operation, adsorption method has become one of the most widely used methods for treatment of heavy metal pollutants in water. Low-cost adsorbent is the key to the application of adsorption method. As a kind of solid waste produced in steelmaking process, steel slag is a good adsorbent with large specific surface area and porous structure. Based on the above viewpoint, the adsorption and removal characteristics of lead and cadmium ions in water were studied by using steel slag as adsorbent. The chemical composition, properties and structural characteristics of steel slag were analyzed by means of chemical composition analyzer XRDX et SEM. The results show that the main composition of steel slag is Cao, which is soluble in water and is alkaline. It is found that the surface of steel slag is rough and porous, which is beneficial to the adsorption of heavy metal ions in water. Through the static adsorption experiment of single ion, the effects of adding amount of steel slag, initial pH of solution, reaction temperature and reaction time on the adsorption effect were studied. The results showed that the addition amount and reaction time of steel slag had great influence on the removal efficiency. The optimum mass addition ratio of steel slag is 1: 10 for lead / steel slag and 1: 20 for cadmium / steel slag respectively. The initial pH value and temperature have little effect on the adsorption of heavy metal ions by steel slag, and the steel slag can adapt to the change of wastewater. The mechanism of removing heavy metal ions from steel slag was also studied. The adsorption and chemical precipitation were the main mechanisms of removing lead ion and cadmium ion by observing the experimental phenomenon and analyzing by SEM. Through the study of adsorption mechanism, the quasi-second-order kinetic model and Langmuir model can better describe the adsorption process of lead and cadmium ions in steel slag, and the adsorption rate of steel slag to lead and cadmium ions in water is controlled by chemical adsorption mechanism. The adsorption form is monolayer adsorption. The experimental results of dynamic adsorption show that the penetration time increases with the increase of bed height, but decreases with the increase of influent velocity and initial concentration of influent. The dynamic adsorption process accords with the Thomas equation and the correlation coefficient R2 is above 0.9. The operating parameters of the adsorption column can be accurately predicted by using the equation. The results show that the maximum adsorption amounts of lead ion and cadmium ion on steel slag adsorption column are 69.86 mg/g and 55.14 mg / g, respectively, and the dynamic competitive adsorption results also show that the preferential order of adsorption of lead ion and cadmium ion on steel slag is Pb2 Cd2.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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