Fluorescent characteristics and metal binding properties of individual molecular weight fractions in municipal solid waste leachate

Molecular weight (MW) is a fundamental property of dissolved organic matter (DOM), which potentially affects the binding behavior between DOM and metals. Here, a combined approach of ultrafiltration fractionation, fluorescence excitation-emission matrix quenching and parallel factor analysis (PARAFAC) was employed to elucidate fluorescent characteristics and metal binding properties of individual MW fractions of DOM in landfill leachate. Four humic-like and two protein-like components were identified by PARAFAC. Among them, a fulvic acid-like component was found to be responsible for Cd(II) binding while Cu(II) inclined to complex with humic-like components rather than protein-like ones. Apart from that, MW was found to exert less influence on metal binding than that of specific metals or components. Key components distributed within various fractions of DOM were the main influence on the impact of MW on metal binding.

► We examined binding behavior between heavy metal and individual MW fractions of DOM.
► MW was found to exert less influence on binding than that of metal or component.
► MW impact on binding was induced by key component distributed in various fractions.
► FA-like substance was found to be responsible for Cd(II) binding.
► Cu(II) tended to complex with HS (high MW) rather than protein substance (low MW).