摘要
探讨非极性的菲和极性的1,3-二硝基苯在不同阳离子饱和高岭石和蒙脱石上的吸附机制。结果表明,不同阳离子饱和矿物对1,3-二硝基苯的吸附量均高于菲。1∶1型高岭石阳离子交换量和比表面积均低于2∶1型蒙脱石,对菲和1,3-二硝基苯的吸附量也较弱。Zeta电位按照K+、Ca2+和Al3+饱和矿物的顺序从负电荷方向逐渐趋于0,表明矿物表面疏水性逐渐加强,与菲的疏水性作用更强。X射线衍射分析显示,离子饱和矿物吸附菲后层间距增大,表明菲进入层间。Al3+饱和蒙脱石吸附菲前后层间距均为最大,对菲的层间容纳能力最强,因此,Al3+饱和矿物对菲的吸附量均高于K+和Ca2+饱和矿物。K+较弱的水分子竞争及空间位阻作用使得K+饱和矿物对1,3-二硝基苯的吸附量更高,3价的Al3+相对2价的Ca2+具有更强的阳离子架桥能力,提高了1,3-二硝基苯在Al3+饱和矿物上的吸附量。
The paper is to make a further exploration of the dominant mechanism responsible for adsorption of nonionic organic compounds on different cation-saturated kaolinite and smectite based on the study of the adsorption mechanism of the organic contaminants on the clay minerals, nonpolar nonionie compound （phenanthrene, PHE） and the polar nonionie compound （ 1,3-dinitrobenzene, DNB）. The re- sults of our study demonstrate that the cation-saturated kaolinite and smectitc can adsorb larger amounts of DNB than PHE. 1 ： 1 type lay- ered kaolinite with relatively fiat and smooth surface is more con- densed. Smectite with larger surface area and CEC value proves to have a stronger adsorption capacity for both PHE and DNB than kaolinite itself. Zeta potential gradually approaches neutral, exhibit- ing the following negative order： K＋ -modified 〉 Ca2＋ -modified 〉 A13＋ -modified minerals, indicating that the surface hydrophobicity tends to get enhanced, which is likely to result in a facilitating by_ drophobic adsorption of PHE on the solid surfaces. X-ray diffraction analysis has also shown that the layer distance turned to have in- creased when it was interacting with PHE, which may signify there exists the interlayer PHE. However, the layer distance of AI3 ＋ -modi- fied smectite has been the largest no matter whether it was before or after its interaction with PHE, thus revealing the strongest adsorption capacity for PHE, whereas K~ -modified smectite with the smallest layer distance tends to have the lowest adsorption capacity for PHE. Thus, it is easy to prove that the Al3 ~ -saturated clay mineral enjoys greater adsorption capacity for PHE than the K＋ - and Ca2＋ -saturated clay minerals may have. At the same time, weakly hydrated ex- changeable cation of K＋ with relatively small hydration sphere can promote the increase of the effective size of the adsorptive domains of K ~ on the clay surfaces and therefore help to enhance the adsorption amount of DNB. As a trivalent cation, A13 ＋ has be
出处
《安全与环境学报》
CAS
CSCD
北大核心
2015年第2期200-204,共5页
Journal of Safety and Environment
基金
国家水体污染控制与治理科技重大专项(2012ZX07103-005)
国家自然科学基金项目(21407053
41371444
31300422)
安徽省自然科学基金项目(1308085MB28
1408085QC47)
安徽省自然科学重大项目(KJ2013ZD07)
关键词
环境工程学
黏土矿物
吸附
菲
1
3-二硝基苯
environmental engineering
clay mineral
adsorption
phenanthrene
1,3-dinitrobenzene
