吸附材料对黄河兰州段河岸带沉积物中氨氮吸附-解吸的影响  

Effect of adsorption materials on adsorption-desorption of ammonia-nitrogen in riparian sediments in Lanzhou section of the Yellow River

作　　者：王若凡 田开栋 杨光[1,2] 李佩钢 刘雨欣 WANG Ruofan;TIAN Kaidong;YANG Guang;LI Peigang;LIU Yuxin(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of the Yellow River Water Environment in Gansu Province,Lanzhou 730070,China)

机构地区：[1]兰州交通大学环境与市政工程学院,兰州730070 [2]甘肃省黄河水环境重点实验室,兰州730070

出　　处：《环境工程学报》2024年第7期1828-1839,共12页Chinese Journal of Environmental Engineering

基　　金：国家自然科学面上基金资助项目(51969011);甘肃省自然科学基金资助项目(23ZDFA002);甘肃省高等学校创新能力提升项目(2020B-109)。

摘　　要：采用原位覆盖技术可有效提升河岸带沉积物对陆源污染物的吸附作用,且有效控制沉积物内源污染物释放。本研究以沸石、混凝土渣和活性炭作为覆盖材料的代表,结合BET、SEM-EDS、FTIR、XRD等表征手段,通过吸附动力学实验、吸附热力学实验、混合实验及原位覆盖实验对覆盖材料的氨氮吸附效果及机理进行对比分析,同时研究材料对河岸带沉积物中氨氮吸附及解吸的影响。结果表明,3种材料对20 mg·L^(-1)氨氮溶液中氨氮的吸附动力学表现为:沸石和生物炭在180 min可达到吸附释放平衡,混凝土渣则需720 min。随着环境温度的升高,材料的吸附量不断增加,沸石的理论吸附量值最大。三种材料对氨氮的吸附均属于可自发进行的吸热过程,活性炭吸附主要以物理吸附为主,而沸石、混凝土渣还伴有化学吸附。表征分析结果表明,沸石、混凝土渣在吸附氨氮过程中,两者的羟基官能团与氨氮形成氢键或存在静电引力,这有利于两者对氨氮的吸附,其中混凝土渣的硅氧键及铝氧键官能团也参与了氨氮的吸附。吸附后,沸石的晶体结构未发生改变,但混凝土渣的表面结构受到一定的影响。混合吸附/释放实验结果表明,与无材料添加的对照实验组比较,沸石、混凝土渣和活性炭分别添至沉积物并吸附12 h后,对氨氮质量浓度为20 mg·L^(-1)上覆水中氨氮的吸附率分别提升了23.04%、9.41%和15.72%。但3种材料添至沉积物后对沉积物内源氨氮的控释效果存在差异,添加沸石和活性炭组对沉积物中氨氮的控释率分别提高了6.24%和0.80%,添加混凝土渣组促进了沉积物中氨氮的释放。通过综合对比,沸石吸附氨氮效果最佳,活性炭次之,混凝土渣最差。通过进一步的原位覆盖实验,连续观察14 d后,发现沸石作为原位覆盖材料对上覆水中氨氮吸附率可提升约21.58%,且无诱发沉积物中氨氮释放风险,可成为黄�The use of in-situ cover technology can effectively enhance the adsorption of land-based pollutants by riparian sediment and effectively control the release of endogenous pollutants in sediments.In this study,zeolite,concrete slag,and activated carbon were used as representatives of cover materials(inorganic/activated),combined with BET,SEM-EDS,FTIR,XRD,and other characterization means,to comparatively analyze the ammonia nitrogen adsorption effect and mechanism of the cover materials through adsorption kinetic and thermodynamic experiments,mixed experiments and in-situ covering experiments,the effect of the materials on the adsorption and desorption of ammonia nitrogen in the sediment of the riparian zone was also studied.The results showed that the adsorption kinetics of ammonia nitrogen in 20 mg·L^(-1)ammonia nitrogen solution on the three materials were following:zeolite and biochar could reach the adsorption-desorption equilibrium in 180min,while concrete slag took 720 min.With the increase of the ambient temperature,the adsorption capacity of the material increased,and the theoretical adsorption value of zeolite was the largest.The adsorption of ammonia nitrogen on the three materials was a spontaneous endothermic process,and the physical adsorption mainly occurred on activated carbon,while the chemical adsorption adsorption also accompanied on zeolite and concrete slag.The results of characterization analysis showed that the hydroxyl functional groups of zeolite and concrete slag could form hydrogen bonds with ammonia nitrogen or produce electrostatic attraction during the adsorption of ammonia nitrogen,which was conducive to the adsorption of ammonia nitrogen,of which the silica-oxygen and aluminum-oxygen bonding functional groups of concrete slag also took part in the adsorption of ammonia nitrogen.After adsorption,no changes happened in the crystal structure of zeolite,but some changes appeared on the surface structure of concrete slag.The results of the mixed adsorption/release experiments showed that

关 键 词：原位覆盖材料 河岸带沉积物 氨氮 吸附固定 内源释放 

分 类 号：X703.1[环境科学与工程—环境工程]