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以西北黄土为研究对象,采用批量法研究不同温度下制得的生物炭对西北黄土吸附敌草隆的影响.结果表明,敌草隆在添加不同质生物炭黄土上的动力学吸附过程较好地符合准二级吸附动力学模型,且吸附过程主要分为快吸附(0~8 h)和慢吸附(8~12 h)两个阶段,在12 h左右达到平衡;热力学较好地符合Freundlich等温吸附模型;添加生物炭的黄土对敌草隆的吸附量随着温度的升高而增大,且吸附过程中ΔG~θ小于0,ΔH~θ和ΔS~θ大于0;不加生物炭的黄土对敌草隆吸附量则随着温度的升高而降低,且吸附过程中ΔG~θ和ΔH~θ小于0,ΔS~θ大于0;在体系温度范围内,E(吸附平均自由能)为1.29~5.00 k J·mol-1,表明无论是否添加生物炭,黄土对敌草隆的吸附都以物理吸附为主.其影响因素分析结果显示,随着生物炭热解温度的升高,溶液中敌草隆的平衡浓度降低,平衡吸附量增大;添加生物炭的黄土对敌草隆吸附量在0.5~6 mg·L-1浓度范围内快速上升,之后吸附量随初始浓度的升高缓慢增加并逐渐趋于平衡;溶液pH对黄土吸附敌草隆有一定影响,但影响不大.
The effects of biochar obtained at different temperatures on diuron-adsorption of diuron in northwestern loess were studied by means of batch method in northwestern China.The results showed that the kinetic adsorption of diuron on biotrophic loess with different biotransformations was better The groundwater is in accordance with the quasi-second-order adsorption kinetics model. The adsorption process is mainly divided into two stages of fast adsorption (0 ~ 8 h) and slow adsorption (8 ~ 12 h), and equilibrium is reached at 12 h. The thermodynamics is in good agreement with Freundlich Isothermal adsorption model. The adsorption capacity of diuron with biochar to diuron increased with the increase of temperature, and ΔG ~ θ was less than 0 and ΔH ~ θ and ΔS ~ θ were greater than 0 in the adsorption process. Without biochar Of loess to diuron decreased with the increase of temperature, and ΔG ~ θ and ΔH ~ θ were less than 0 and ΔS ~ θ was greater than 0 in the adsorption process. In the system temperature range, E (average free energy of adsorption ) Was 1.29-5.000 kJ · mol-1, indicating that the adsorption of diuron on diuron was mainly physical adsorption regardless of the addition of biochar.The analysis of its influencing factors showed that with the increase of pyrolysis temperature of biochar, , The equilibrium concentration of Diuron in the solution decreased and the equilibrium adsorption capacity increased. Adding loess with biochar to the enemy The adsorption capacity increased rapidly in the concentration range of 0.5-6 mg · L-1, and then increased slowly with the increase of initial concentration and gradually became equilibrium. The pH of the solution had some influence on the adsorption of diuron on loess, but the effect was not significant Big.