生物炭对诺氟沙星在土壤中吸附行为的影响
Effects of biochar on adsorption of nofloxacin in tropical soils
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摘要: 以甘蔗渣为前驱材料,在3 种温度(350、450、550℃)下制备不同碳化度的生物炭(分别记为BC350、BC450、BC550),研究其对诺氟沙星在砖红壤中吸附行为的影响。结果表明,诺氟沙星在砖红壤和生物炭土壤上(W/W,1.0%)的吸附动力学过程包括快速和缓慢两个阶段,伪二级动力学模型能较好地拟合砖红壤和生物炭土壤吸附诺氟沙星的动力学过程(r ≥ 0.963,P < 0.01);添加质量浓度分别为0.1%、0.2%、0.5%、0.8%、1.0% 的3 种生物炭提高了砖红壤对诺氟沙星的吸附量,且随着生物炭添加量的增加,吸附量逐渐增加,添加生物炭后砖红壤对诺氟沙星的单点吸附值是砖红壤的1.04~2.34 倍。诺氟沙星在生物炭土壤中的吸附过程能够采用Freundlich 模型、Langmuir 模型和Tekmin 模型进行较好的拟合(r ≥ 0.910,P < 0.05);生物炭土壤对诺氟沙星的非线性吸附过程主要受到表面吸附作用、分配作用和其他微弱作用力共同影响。生物炭的施入可以提高土壤对有机污染物的吸附能力,从而降低有机污染物的生态环境风险。Abstract: A series of biochar were prepared by pyrolyzing sugarcane bagasses,a typical tropical agricultural wastes,at three different pyrolysis temperatures(350,450,550℃),which were referred as BC350,BC450 and BC550. The effects of biochar on adsorption of nofloxacin on Latosols and the dominant mechanism of nofloxacin environmental behavior in biochar soils were studied. Results showed that adsorption on Latosols and biochar-amended soils(W/W,1.0%)included two steps,the fast reaction and the slow reaction. The adsorption kinetics of nofloxacin on Latosols and biochar-amended soils(W/W,1.0%)accorded with the pseudo-second-order kinetics equation(r ≥ 0.963,P < 0.01). When biochar amendment rates were set as 0.1%,0.2%,0.5%,0.8% and 1.0%(W/W)of soils, it could significantly increase the adsorption of nofloxacin on Latosols,and the adsorption quantity increased with the increasing quantity of biochar. The single-point adsorption values of nofloxacin on biochar-amended soils were 1.04-2.34 times higher than the on Latosols. The adsorption and desorption data over the entire range of antibiotics concentrations were well described by the Freundlich equation,Langmuir equation and Tekmin equation with r ≥ 0.910 and P < 0.05. Mechanism of adsorption of nofloxacin on biochar-amended soils included surface adsorption,partition and other weak forces. Application of biochar in soil could increase the adsorption of organic pollutant in soil to decrease the ecology risk.