编号：CDUT-2024-20

标题：Retarding performance of the vadose zone for nitrogen pollutants derived from municipal solid waste landfills in the red bed zone

入藏号：WOS:000783626100002

中国科学院文献情报中心期刊分区： 环境科学与生态学1区TOP（2022）

本校作者：李娜英; 韩智勇*, 任怡;王双超; 胡馨然;曾卓君

* Corresponding author.

来源出版物：JOURNAL OF ENVIRONMENTAL MANAGEMENT  卷: 306  文献号: 114406 

出版年：2022

第一地址：成都理工大学      

关键词：Ammonia；Nitrate；Adsorption；Migration；Municipal solid waste landfil；adose zone in red bed

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摘要：Nitrogen pollutants such as ammonia and nitrates cause soil and groundwater contamination at municipal solidwaste landfill (MSWL) sites due to leachate leakage. Here, the migration of nitrogen pollutants in the vadose zoneof the red bed (VZRB) at a MSWL site was studied by static adsorption batch experiments and one-dimensionalsimulated migration experiments. The results indicated that the soil in the red bed did not adsorb nitrates.Chemical adsorption and monolayer adsorption of the soil played dominant roles during ammonia adsorption inthe VZRB, which was best fitted by the pseudo-second-order kinetic equation (R2NH+4= 0.99) and the Langmuirmodel. The ammonia adsorption capacity of the soil was the highest (Qm = 2.041 mg⋅g− 1) at 318 K. It was due tothe endothermic and non-spontaneous chemical adsorption of ammonia, whose enthalpy change (ΔH) reached20.995 kJ⋅mol− 1 and Gibbs free energy ranged from 8.469 to 8.706 kJ⋅mol− 1. Chloride penetration tests indicated that the diffusion coefficient and migration speed reached 0.0515 cm2⋅h− 1 and 0.0833 cm⋅h− 1, respectively, in the clay layer under the MSWL sites. The average hysteresis diffusion coefficients of ammonia in thesimulated soil columns leached by ammonium chloride solution (SSCAC) and by the leachate from MSWL (SSCL)were 1.129 and 1.400, respectively. After the leaching experiments, the clay pore structure was saturated, andthe specific surface area decreased. The absorption peak intensities of clay functional groups, including carboxyl,alkyne, and hydroxyl groups, were reduced. The ammonia content in the soil of SSCAC decreased from the top(14.51 mg⋅kg− 1) to the bottom (3.14 mg⋅kg− 1) and in the SSCL from 24.96 mg⋅kg− 1 to 5.05 mg⋅kg− 1, respectively. Thus, the impermeable clay layer and VZRB helped in retardation of ammonia leakage from MSWL sites.This was due to the blockage of seepage, ammonia mechanical filtration, ammonia monolayer chemicaladsorption, and the reaction between the functional groups and ammonia in the VZRB underneath the MSWLsites.

文章链接地址: https://www.sciencedirect.com/science/article/pii/S0301479721024683?via%3Dihub