红层粉质粘土对核素的吸附阻滞效应研究-环境工程专业论文.docxVIP

西南科技大学硕士研究生学位论文 第1页 摘要 中低放废物在放射性废物中占绝大多数，对中低放废物的近地表处置是 一种可行的处置方法。本文即以绵阳紫红粉质粘土为吸附基材，运用现代化 分析测试手段对土样的物理化学成分及性质进行了分析，并将静态试验方法 与动态吸附试验方法相结合，对粘土吸附阻滞核素同位素的效果进行了研 究，取得如下成果： 1、粘土主要成分为石英，此外，还含有蒙脱石、沸石、伊利石、等多 种矿物成分，阳离子交换量较大，吸附性能较好。 2、粘土对Sr2+、Cs+的吸附效果较为理想，尤其是对Cs+的吸附，在溶 液初始浓度小于lOmg／L或者固液比大于1：10的情况下，其吸附比可大于 600m L／g。粘土对Sr2+、Cs+的吸附遵循Freundlich等温吸附方程规律，其 等温吸附方程表达式分别为Qe=O．1315Ce 0‘6627和Qe=O．5662Ce 0‘6636 o 3、溶液初始浓度增大，吸附量增大，吸附率和吸附比减小；固液比增 大或者粘土粒径减小，吸附量、吸附率和吸附比均增大；粘土对Sr2+的吸附 随着pH的增大而增大，粘土对Cs+的吸附在pH为5-7范围内较佳。 4、添加黄铁矿和腐殖质能显著的改善粘土的吸附性能。 5、在地下水淋洗强度为lmL／h的条件下，Sr2+、Cs+在原状土中的迁移 速度分别约为32cm／a、5．Ocm／a。 关键词：粘土 锶 铯 静态试验 动态试验  Abstract Low and intermediate level nuclear waste is the main part of Nuclear Waste， and surface disposal method has been thought to be a realistic approach to dispose of low and intermediate level nuclear waste．In this paper，aubergine siltv clay was used to be the experimental material，morden analysi s and tesying technology was used to analyse the physical and chemical composition and properties of the sility clay，static test was combined with dynamic test，in order to studv the adsorption and detention properties of the silty clay，and the relevant results were obtained． 1．Quartz is the maj or composition of the silty clay，mineral composition such as montmorillonite，zeolites，illite， etc．was also contained in silty clay， cation exchange capacity is ideal for adsorption． 2．The effection of silty clay is ideal，especially for cesium．The adsorption ratio of cesium by silty clay may be greater than 600 mL／g while the solution concentranon is less than 1 0mg／L or the solid-to-liquid ratio is greater than 1：1 0．It keeps to Freundlich equation orderliness that silty clay adsorb Sr，Cs， the adsorption equation of Sr and Cs are Qe=0．1 3 1 5Ceo·6627 and Qe=0．5662Ceo-6636． 3．With the increasing of solid-to-liquid ratio，equilibrium absorption amounts increase，while the equilibrium absorption rates and equilibriu。m absorption ratio decrease．The solid—to—liquid ratio increase o