摘要
采用静态间歇法 ,实验研究了含Pb2 +废水的 pH值及吸附时间对 13X沸石分子筛吸附Pb2 +性能的影响 ,得出了最佳去除效果的优化条件为 :废水的 pH值接近中性 ,吸附时间 10min。通过吸附实验 ,确定了在Pb2 +初始浓度为 2 0mg/L的条件下 ,13X沸石对Pb2 +的吸附量为 2 1 4 2mg/g ,即每克沸石净化含Pb2 +废水的最大体积量约为 75 0mL。解析实验表明 ,加入沉淀剂 ,浓缩洗脱液中的Pb2 +即以PbS的形式生成沉淀 ,为回收金属铅提供了可能 ;13X沸石在循环使用 5次的条件下 ,对废水中Pb2 +的吸附率仍高达 98% ,重复使用性能良好。经处理后的净化水中Pb2 +的浓度小于 0 4mg/L ,显著低于国家废水排放标准GB8978 88的指标 ( 1 0mg/L)。 13X沸石对Pb2 +的主要吸附形式是离子交换和表面络合反应。
X zeolite molecule sieve synthesized from natural alkaline rocks was used to absorb Pb 2+ in wastewater in this study by ion exchange and absorption experiments. The regeneration of 13X zeolite and the maximum volume of wastewater purified were explored. The experimental results showed that the efficiency of 13X zeolite as an agent capturing heavy metal ion Pb 2+ was as high as 98% or more, and concentration of Pb 2+ in the so-purified water was less than 0.4 mg/L, substantially below 1.0 mg/L stipulated by the China national wastewater discharge standard GB8978-88. Meanwhile, no efficiency reduces were found in the experiment with increasing the recycles of 13X zeolite absorbing Pb 2+ in water up to five cycles. The absorption capacity of 13X zeolite on Pb 2+ was up to 21.42 mg/g(zeolite),given the initial Pb 2+ concentration being 20 mg/L in the wastewater. In the solution concentrated with Pb 2+ desorbed from the Pb 2+ saturated zeolite after adsorption, Pb 2+ could be well precipitated as lead sulfide PbS by adding Na 2S, from which it is possible to recover metallic lead by the ordinary metallurgical processes. The mechanism for adsorption of 13X zeolite on Pb 2+ was suggested to be ion exchange and surface complex absorption, as well as general physical absorption.
出处
《现代地质》
CAS
CSCD
2003年第2期157-162,共6页
Geoscience
基金
教育部博士学科点基金项目 ( 19990 49114 )。
