摘要
沉积物是海洋生态系统磷循环的载体之一,铁氧化物作为海洋沉积物活性组分的重要部分,对磷在沉积物上的吸附解吸有着重要贡献,进而影响着磷在沉积物-水界面的交换。本文利用自行合成的α-Fe_(2)O_(3)和无定形氧化铁,研究了无机磷(以KH_(2)PO_(4)为例)在其上的吸附特征,并考察了离子强度等对该吸附过程的影响。结果表明,无定形氧化铁对无机磷的吸附平衡时间较短且吸附量较大,这与其较差的结晶度,较大的比表面积有关。无机磷在氧化铁上的吸附等温线符合Freundlich吸附等温式,研究发现两种铁氧化物的吸附热力学函数均为ΔH^(θ)>0,ΔG^(θ)<0,ΔS^(θ)>0,说明整个吸附过程是吸热、自发、熵增加的过程;随着离子强度的增大,无机磷在两种铁氧化物上的平衡吸附量增加,吸附pH边曲线实验发现,无定形氧化铁对无机磷的吸附量随着pH的升高而减小。
Sediment is one of the important carrier of phosphorus cycle in marine ecosystems.As an important composition of sediment for sorption behavior,iron oxide plays a considerable role on phosphorus sorption and desorption process,which deserve more attention during phosphorus exchange at the sediment-water interface.The sorption behaviors of phosphorus onto two kinds of iron oxides(α-Fe_(2)O_(3),amorphous iron oxides)were studied in this paper.The sorption kinetic and thermodynamic characteristics were investigated.The results are as follows,the sorption equilibrium time of amorphous iron oxide is shorter and the equilibrium sorption amount is larger than those ofα-Fe_(2)O_(3) under the same circumstances,which is related to the poor crystallinity and large specific surface area of amorphous iron oxide.The sorption isotherms fit the Freundlich sorption isotherm well.The calculation of the thermodynamic parameters showsΔH^(θ)>0,ΔG^(θ)<0 andΔS^(θ)>0,indicating that the sorption is an endothermic and spontaneous process with an entropy increase.Moreover,with the increase of ionic strength in NaNO_(3) medium,the equilibrium sorption amount of inorganic phosphorus on the two iron oxides increased.With the phosphate sorption pH edge curves result shows that the sorption capacity of phosphorus on amorphous iron oxide decreases with the increase of pH.
作者
郭智俐
李苓
刘晓月
李敬
曹晓燕
Guo Zhili;Li Ling;Liu Xiaoyue;Li Jing;Cao Xiaoyan(Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education,Institute for Advanced Ocean Study, Ocean University of China, Qingdao 266000, China;Laboratory for Marine Ecology and Environmental Science, Polit National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China;College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266000, China)
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2021年第8期42-48,共7页
Periodical of Ocean University of China
基金
国家自然科学基金项目(41676064)
国家重点研究发展计划项目(2016YFA0601301)资助。
关键词
富营养化
无机磷
铁氧化物
吸附动力学
吸附等温线
eutrophication
inorganic phosphorus
iron oxide
sorption kinetics curve
sorption isotherm
作者简介
郭智俐(1996-),女,硕士生,研究方向:海洋界面化学;通讯作者:曹晓燕,E-mail:caoxy@ouc.edu.cn。
