摘要
以生活污水处理厂剩余活性污泥为原料,制备粉末活性污泥(PAS)作为生物吸附剂,考察p H值,PAS投加量,U(Ⅵ)初始浓度和吸附时间对PAS吸附U(Ⅵ)的影响,探讨了PAS吸附U(Ⅵ)的作用机理。实验结果表明,在U(Ⅵ)初始浓度为10 mg/L时,其最佳吸附p H值为3,去除率97.77%,吸附平衡时间120 min;吸附过程较好地拟合了准二级动力学模型(R2≈1)和Freundlich等温模型(R2≈1);X射线能谱和离子交换实验分析表明,离子交换为其主要吸附方式,参与交换的主要离子为Ca2+;红外光谱分析表明,PAS吸附U(Ⅵ)后自身结构未发生改变。以0.1 mol/L的HCl溶液作为解吸液,初次解吸率达92.83%,循环利用3次仍具有较好的吸附效果。
The residual activated sludge from an urban sewage treatment plant was used to prepare powdered activated sludge( PAS) as a novel biological adsorbent. Different experimental parameters such as solution p H,adsorbent dose,initial concentration and contact time were examined to investigate their effects on adsorption of uranium by PAS. Changes of FT-IR spectra,scanning electron microscope and energy-dispersive spectrometry of PAS before and after adsorption were also studied. The results showed that the maximum adsorption occured at p H of 3,the adsorption reaches equilibrium within 120 min and the removal rate was up to 97. 77%for initial U( Ⅵ) ions concentration of 10 mg / L. The equilibrium data fit well with the pseudo-second-order model( R2≈1) and Freundlich model( R2≈1). Ion exchange experiments and EDS analysis verified that ion exchange was the main adsorption mechanism with Ca2 +as the main exchange ion. FTIR spectra before and after PAS adsorbed uranium indicated that its structure did not change. The used PAS can be desorbed by 0. 1 mol / L HCl( the first desorption rate is up to 92. 83%) and became reusable. PAS is nontoxic and eco-friendly,which has a good prospect in the treatment of uranium-containing wastewater.
出处
《环境工程学报》
CAS
CSCD
北大核心
2015年第3期1141-1147,共7页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(11175081)
高等学校博士点基金项目(20134324110003)
湖南省自然科学基金项目(13JJ3078)
湖南省高校创新平台项目(13K085)
关键词
活性污泥
吸附
铀(Ⅵ)
解吸
离子交换
activated sludge
absorption
uranium(Ⅵ)
desorption
ion exchange
