为探讨覆盖不同材料对湖泊沉积物磷释放控制机制,通过室内模拟试验,研究了覆盖FezO3、Al2O3、MnO2等3种氧化物及湖沙、蛭石对洱海沉积物磷释放特征、沉积物磷形态、金属形态及环境因子的影响.结果表明:(1)覆盖不同材料均抑制了沉积物磷释放,Fe组、Mn组、A1组、湖沙组和蛭石组沉积物中TP的Qm.分别减少了40.36％、32.07％、26.25％、11.62％和-7.83％.(2)覆盖材料主要是降低了沉积物中NH4C1-P、BD-P、NaOH-P的含量,其中覆盖金属氧化物降幅均高于湖沙和蛭石,覆盖Fe氧化物降低幅度最大,覆盖Mn氧化物对NaOH-P降幅较高.(3)覆盖材料通过影响Fe、A1、Mn及TOC在各磷形态中含量,进而控制磷的释放,其中Fe组沉积物BD-Fe和HCl-Fe含量分别增加了23.81％、110.76％,Mn组沉积物NH4C1-Mn增加110.76％,各组沉积物中NaOH-A1均向HCl-A1转化,且使沉积物TOC含量降低,进而增大沉积物w(TTOC/TP)、w(TFe/TP)、w(TMn/TP)、w(TAL/TP)比值,促进活性磷向惰性磷的转化.(4)覆盖材料通过影响沉积物pH和Eh值,进而影响金属离子形态,控制磷的释放.总体来看,覆盖金属氧化物控磷效果高于非金属无机材料,金属氧化物不仅具有吸附磷等物理作用,而且具有金属离子与磷结合转化磷形态含量的化学作用,进而控制沉积物磷释放,其中Fe氧化物控制效果最高.
To investigate the impact of different capping materials on the phosphorus release from lake sediment,indoor simulation experiments were conducted.Phosphorus release mechanisms from Erhai lake sediment capped by ferric oxide,aluminium oxide,manganese oxides and lake sand,vermiculite were studied.Results showed that:(1) phosphorus release from the sediment was inhibited under all treatment procedures.Sediment TP Q max under Fe,Mn,A1,lake sand and vermiculite treatment was reduced by 40.36％,32.07％,26.25％,11.62％ and-7.83％ respectively.(2)Cover material mainly reduced the NH4 C1-P,BD-P,NaOH-P content,and the decline by the metal oxides was larger than lake sand and vermiculite,Fe oxides reduction is the largest,followed by the Mn oxides.(3)Cover material affected the sediment phosphorus release by changing Fe,A1,Mn and TOC content in different phosphorus forms.Sediment BD-Fe and HC1-Fe content increased by 23.81％ and 110.76％ respectively in Fe group,and in Mn group sediment NH4C1-Mn content increased by 110.76％.Sediment NaOH-Al under each treatment was all transformed into HC1-A1.And sediment TOC content decreased correspondingly,further increasing the sediment w (TTOC/TP),w (TFe/TP),w (TMn/TP),w (TAl/TP) ratios.This helped promote the transformation of labile phosphorus into inert phosphorus.(4) Sediment pH and Eh were changed after capping with different materials which influenced metal speciation and then controlled sediment phosphorus release.Overall,metal oxide showed higher phosphorus immobilization efficiency than other inorganic non-metallic materials,metal oxides can not adsorb phosphorus,but also induce phosphorus transformation through metal iron binding,which control the sediment phosphorus release,and the Fe oxides demonstrated the best efficiency.
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