生物炭对磺胺类抗生素在石灰性紫色土中迁移行为的影响

发布时间：2018-03-29 12:17

本文选题：紫色土　切入点：生物炭　出处：《西南交通大学》2017年硕士论文

【摘要】：紫色土是西南地区的主要耕作土壤,而生物炭作为一种新型环保材料在土壤污染物控制方面应用广泛。本文以川中丘陵区坡耕地紫色土为研究对象,通过批量平衡实验、柱实验和田间试验研究了生物炭施用(投加量0、39.75 t/hm2(1%BC)和198.75 t/hm2(5%BC))及田间老化作用(夏季干湿交替)对三种典型磺胺类抗生素(磺胺嘧啶(SD)、磺胺二甲基嘧啶(SM2)及磺胺甲恶唑(SMZ))在紫色土中迁移行为的影响。研究主要结果如下:(1)在不同处理中,三种磺胺类抗生素吸附强弱的顺序都表现为SDSMZSM2;与对照土对三种磺胺抗生素的吸附相比,添加生物炭能增加土壤对三种抗生素的吸附能力,其中SM2的吸附显著增加(P0.05),但这种促进作用在经过老化过程后有所减弱。在解吸过程中,三种抗生素的Freundlich常数沿大小顺序为SDSMZSM2,表明SD在土壤中吸附容量最大且不易解吸,其次是SMZ和SM2;相应的迟滞系数H大小顺序为SDSMZSM2,与Freundlich常数n值趋势一致,表明紫色土对SD亲和力最强,解吸最难,而SM2则解吸最易,可逆性最强。(2)对照土柱和1%BC 土柱中都存在大孔隙,对照土柱大孔隙比1%BC的土柱更发达;污染物会通过大孔隙以优先流通过土壤进入地下水环境,生物炭的添加改善土壤孔隙结构,减少了大孔隙,降低了优先流通过土壤污染地下水的可能性。(3)土壤中淋出的溶解性有机物(DOM)浓度与土壤孔隙水中离子浓度随淋溶时间呈反比。生物炭会改变了土壤理化性质,从而影响浸出液的溶解性有机物(DOM)的种类,生物炭的添加在一定程度上减少了土壤中DOM的溶出,这在保持土壤肥力方面具有重要意义。(4)不同炭处理方式下地表径流中三种磺胺抗生素的迁移有着不同的变化:未施生物炭小区中大量磺胺抗生素在降雨初期就随地表径流流出,这是因为紫色土坡耕地抗降雨冲击能力较差;耕作层面施1%生物炭小区中,强降雨初期三种磺胺抗生素流出减少且效果明显,污染物随着降雨事件进行逐渐释放;5%生物炭地埂和地沟小区对地表径流中三种磺胺抗生素的截留效果最好,浓度远低于对照小区和面施1%生物炭小区。(5)坡耕地决定污染物更容易从坡上部迁移到下部,因而在整个降雨事件中,三种磺胺抗生素在土壤各深度的浓度并不一定直接下降,可能会先增加后降低,这一现象在耕作层面施1%生物炭的小区比对照小区更明显。5%生物炭地埂小区,三种磺胺抗生素随雨水迁移到一定深度后,水平迁移使其绕过生物炭地埂,并通过溶质扩散和土壤毛细管作用向上迁移。
[Abstract]:Purple soil is the main cultivated soil in southwest China, and biochar, as a new kind of environmental protection material, is widely used in soil pollutant control. In this paper, the purple soil of sloping farmland in the hilly area of central Sichuan is taken as the research object, and the batch balance experiment is carried out. Column and field experiments were carried out to study the effects of biochar application (0 ~ 39.75 t/hm2(1) and field aging (dry and wet alternation in summer) on three typical sulfamethylamine antibiotics (sulfadiazine, sulfamethylpyrimidine (SM2)) and field aging (alternating dry and wet in summer). The effects of sulfamethoxazole (SMZ) on the migration behavior of sulfamethoxazole (SMZ) in purple soil. The main results are as follows: 1) in different treatments, The adsorption order of the three sulfanilamides was SDSMZSM2.Compared with the control soil, the addition of biochar could increase the adsorption ability of the three antibiotics. In the desorption process, the Freundlich constant of the three antibiotics was in the order of SDSMZSM2, which indicated that the adsorption capacity of SD in soil was the largest and it was not easy to desorption. The corresponding hysteresis coefficient H is in the order of SDSMZSM2, which is consistent with the trend of n value of Freundlich constant, which indicates that purple soil has the strongest affinity to SD and the most difficult to desorption, while SM2 is the most easy to desorption. The reversibility is strongest. 2) Macropores exist in both the control soil column and the 1 soil column. The macroporosity of the control soil column is more developed than that of the soil column 1, and the pollutants enter the groundwater environment through the macropores and preferential flow through the soil. The addition of biochar improves the pore structure of the soil and reduces the macroporosity. The concentration of dissolved organic matter (DOM) in soil is inversely proportional to the concentration of ions in soil pore water with the leaching time. Biochar will change the physical and chemical properties of soil. Thus, the species of dissolved organic matter (DOM) of leachate was affected, and the addition of biochar reduced the dissolution of DOM in soil to some extent. This is of great significance in maintaining soil fertility. (4) the migration of three sulfonamides in surface runoff under different carbon treatments has different changes: a large number of sulfamethylamine antibiotics in unapplied biochar plots flow out with surface runoff at the early stage of rainfall. This is due to the poor rainfall impact resistance of sloping land in purple soil, and the decrease of three sulfonamide antibiotics outflow in 1% biochar plot at the early stage of heavy rainfall. With the rainfall event, the pollutants released gradually 5% biochar ridge and gully plot to the surface runoff of the three kinds of sulfamethylamine antibiotic interception effect is the best. The concentration of pollutants in sloping farmland was much lower than that in the control plot and 1% biochar plot. Therefore, the concentrations of three sulfonamides did not decrease directly during the whole rainfall event, and the concentration of the three sulfonamides did not decrease directly in each depth of the soil, so that the pollutants migrated from the upper part of the slope to the lower part of the slope. This phenomenon may increase at first and then decrease. This phenomenon is more obvious in the plot with 1% biochar at the tillage level than in the control plot. After three kinds of sulfamethylamine antibiotics migrate to a certain depth with Rain Water, the horizontal migration causes them to bypass the ridge of biochar. And through solute diffusion and soil capillary action upward migration.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

【参考文献】