【摘要】 通过土柱模拟实验研究含水层介质对垃圾渗滤液污染的pH缓冲和氧化还原缓冲性能.结果表明,碳酸钙对pH缓冲起重要作用,随着污染程度的加重,碳酸钙缓冲体系的缓冲容量逐渐增大,从背景值的1.62.pH-1mmol/kg增加到41.3.pH-1mmol/kg.随着污染程度的加重,含水层介质的氧化容量(OXC)减小,而还原容量(RDC)升高.在未受污染的介质中,Fe3+是OXC的主要组成,约占OXC的70.5%;TOC是RDC的主要组成,约占RDC的98.7%.物质的存在形态也与污染程度有关,在污染源附近大部分无定型态和部分晶体态Fe3+被还原,而且还原产物主要以FeCO3和FeS形式沉淀;生成Fe2+的沉积使得可离子交换态Fe2+含量由未受污染的介质中的0.5%升高至3%.因此,Fe3+是含水层介质中主要的氧化还原缓冲剂.更多还原

【Abstract】 A column filled with fine sand was constructed to investigate pH buffering capacity and redox buffering capacity of aquifer media.Experimental results indicated that calcium carbonate played a significant role in pH buffering;with the aggravating of landfill leachate pollution,the pH buffering capacity of calcium carbonate was increased;it increased from background value,which was 1.62·pH-1 mmol/kg,to 41.3·pH-1 mmol/kg.With the aggravating of landfill leachate pollution,the oxidation capacity（OXC）of aquifer media was decreased,and the reduction capacity（RDC）was increased.In unpolluted aquifer media,Fe 3+ was the main component of OXC,and accounted for about 70.5% of OXC;TOC was the main component of RDC,and accounted for about 98.7% of RDC.Species of the minerals was related to the degree of pollution;large fraction of amorphous Fe 3+ and part of crystalline Fe 3+ were reduced near the pollution source,and the reduced product was mainly precipitated as FeCO₃ and FeS.Deposit of produced Fe 2+ led to ion-exchangeable Fe 2+ content increased from 0.5% of uncontaminated aquifer media to 3%.Therefore,Fe 3+ may act as a very significant redox buffer in aquifer.更多还原