摘要
以吸附去除微污染水中天然有机物（naturalorganicmatter，NOM）为目标，考察了粉末活性炭（PAC）在10～100μm内的粒径变化对其吸附性能的影响，并探讨了PAC粒径变化对不同相对分子质量NOM组分的分级吸附特性．3种不同粒径的PAC由市售PAC经过研磨筛分获得，按照中值粒径（d50）从小到大依次为：PAC-1（19μm）、PAC-2（46μm）和PAC-3（76μm）．吸附实验结果表明，无论对模拟水样还是实际微污染水体中的NOM，随着PAC粒径的减小，PAC对NOM的吸附容量和吸附速率都显著提高．小粒径PAC吸附速率的增加-方面是由于粒径减小导致的有效吸附位点的增加，另-方面粒径减小也使得吸附质分子到达活性炭表面吸附位点的距离减小；而吸附容量的增加主要是由于粒径较小的PAC具有更大的外层比表面积和中孔孔容，有效减弱了相对分子质量大的NOM对活性炭的孔阻塞效应．此外，PAC粒径减小能显著增强其对天然水体中相对分子质量大于2000的有机物组分的吸附，而对相对分子质量小于800的有机物组分的吸附影响相对较小．
The effect of powered activated carbon （PAC） particle size in the range of 10-100 μm on the adsorption of natural organic matter （NOM） in micro-polluted water was investigated, and the adsorption fractionation characteristics in terms of relative molecular mass distribution changes were evaluated. Three PACs with different median particle diameters were obtained through grinding and sieving of a commercial PAC product： PAC-1 （19μm） , PAC-2 （46 μm） , and PAC-3 （76 μm）. The adsorption results showed that with the decrease of particle size, the adsorption properties （both adsorption capacity and adsorption rate） of PAC for NOM in both simulated and real micro-polluted water were significantly enhanced. The faster adsorption rate of PAC with smaller particles was attributed to its more available adsorption sites and shorter diffusion distance for adsorbate molecules. The larger adsorption capacity of smaller particle PACs was mainly due to their greater specific external surface area per unit mass and higher mesopore volume, as the pore blockage effect from large relative molecular mass NOM was alleviated. For micro-polluted water sample, the decrease of PAC particle size significantly enhanced the adsorption of organic matter fractions with relative molecular mass 〉 2 000, but had no notable improvement for that with relative molecular mass 〈 800.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2013年第11期4319-4324,共6页
Environmental Science
基金
国家自然科学基金项目(50878204
51178450)
国家重点基础研究发展计划(973)项目(2011CB933704)
关键词
活性炭
吸附
粒径效应
天然有机物
相对分子质量
powered activated carbon
adsorption
particle size effect
NOM
relative molecular mass
