土壤不同有机组分对诺氟沙星的吸附

通过静态吸附实验,研究了水稻土和赤红壤不同有机组分颗粒物(DOC去除、NaOH提取、375℃灼烧和600℃灼烧)对诺氟沙星的吸附行为。结果表明,DOC去除颗粒物的总有机碳含量(TOC)最高,其他颗粒物的TOC从原始土壤到600℃灼烧后颗粒物逐渐减小。所有土壤不同有机组分颗粒物对诺氟沙星的吸附均表现为非线性吸附,Freundlich模型对吸附数据的拟合效果很好,并且其吸附非线性程度均比原始土壤高。其中,375℃灼烧后颗粒物具有最强的吸附非线性特征,吸附非线性参数n值分别为0.517(水稻土)和0.592(赤红壤)。水稻土不同有机组分颗粒物对诺氟沙星的吸附能力均高于赤红壤。与原始土壤相比,DOC去除和NaOH提取颗粒物的Koc值(ce=0.1mg.L-1)减小,说明其吸附能力降低。相反,375℃灼烧后颗粒物对诺氟沙星Koc值最大,说明其吸附能力最强,而600℃灼烧后的颗粒物的吸附能力最弱。

Study of Norfloxacin Sorptions by Organic Species in the Soils

Sorption isotherms of norfloxacin(NOF) on different organic fractions from a paddy soil and a latosolic red soil(DOC removed,NaOH extracted,375 ℃heated and 600 ℃heated) were determined to compare their sorption behavior for NOF.The TOC content decreased from original soil to the particles heated at 600 ℃,except that the DOC removed particles had the highest TOC.All sorption isotherms of NOF were nonlinear and fitted well by the Freundlich model.The sorption nonlinearity of NOF on all different fractions was higher than the original soils.The particles heated at 375 ℃exhibited the most nonlinear sorption for NOF,with n values of 0.517(paddy soil) and 0.592(latosolic red soil).The different organic fractions of the paddy soil showed stronger sorption for NOF than the latosolic red soil.Compared to original soils,the Koc values(ce=0.1 mg·L-1) of DOC removed and NaOH extracted particles reduced,revealing the decrease of their sorption capacity for NOF.In contrast,the 375 ℃heated particles had the highest Koc values,indicating the strongest sorption for NOF.However,the 600 ℃heated particles exhibited the lowest sorption capacity.