SDS/凹凸棒土对水中碱性嫩黄的吸附及性能  

Performance of Auramine Adsorption from Aqueous Solution on SDS-Modified Attapulgite

作　　者：王翠[1] 汪茜 王春杏 杨恩[1] 

机构地区：[1]武汉科技大学资源与环境工程学院,湖北武汉430081 [2]湖北省环境科学研究院,湖北武汉430072

出　　处：《环境科学与技术》2014年第6期49-54,共6页Environmental Science & Technology

基　　金：国家自然科学基金青年科学基金项目(50904047)

摘　　要：凹凸棒土是一种吸附性能良好的天然无机矿物材料,表面带负电,因而对于水中带正电的阳离子染料碱性嫩黄有一定吸附效果,去除率为59.3%。用阴离子表面活性剂十二烷基硫酸钠(SDS)对其进行改性后,由于将凹凸棒土的表面电性变得更负,吸附效率将会提高。此外,由扫描电镜看出凹凸棒土为纤维状,且晶束间多呈平行紧密聚集,而经SDS改性后的凹凸棒土,晶束在三维空间呈松散交错的排列,更为分散和疏松多孔。由红外吸收光谱看出SDS的特征峰出现在SDS/凹凸棒土中,说明SDS对凹凸棒土起到了良好的改性作用。激光粒度仪测定结果表明SDS/凹凸棒土的中位径d(0.5)由改性前的4.223μm减小到3.758μm,比表面积因而更大,这些变化均会导致改性后的SDS/凹凸棒土有更强的吸附能力。当投加量为0.45 g/L时,吸附30 min后对废水中碱性嫩黄可达吸附平衡,去除率达到80.2%,吸附容量为296.3 mg/g,是活性炭吸附容量129.6 mg/g的2倍多。吸附后的材料经过加热解析再生,吸附性能接近凹凸棒原土,可以再次利用。Attapulgite is a kind of natural inorganic mineral materials with good adsorption performance. As surface of attapulgite is negatively charged, cationic dyes exhibits positive charge, such as auramine, could be effectively adsorbed on it; in this way, the removal rate of auramine from water could reach 59.3%. Higher removal efficiencies can be even achieved by attapulgite modified with sodium dodecyl sulfate （SDS）, an anionic surfactant, as the surface of modified attapulgite is more negatively charged. It has been showed from the image of scanning electron microscopy that attapulgite has a fibrous structure of parallel aggregates; and when attapulgite is modified with SDS, it could be seen the fibers are interknitted resembling a woven texture, so the structure of individual fibers become looser. Additionally, results of infrared spectrum analysis display a characteristic peak of SDS in the SDS-modified attapulgite, indicating a good modification effect on attapulgite by SDS. Furthermore, analysis of the laser granulometric instrument revealed that median diameter of SDS- modified attapulgite diminished to 3.758 μm compared with that （4.223 μm） of the raw attapulgite, thus enhancing its adsorption capacity. The adsorption equilibrium is attained within 30 minutes when the dosage of SDS-modified attapulgite is 0.45 g/L, and the removal rate and adsorption capacity reach to 80.2% and 296.3 mg/g respectively. Comparatively, the adsorption capacity of activated carbon is only 182 mg/g. The experiments conducted also prove that adsorption performance of SDS-modified attapulgite after being desorbed thermally is close to that of the raw attapulgite, which suggests that attapulgite may be reused.

关 键 词：十二烷基硫酸钠(SDS) 凹凸棒土 改性 吸附 碱性嫩黄 

分 类 号：X131.2[环境科学与工程—环境科学]