Additional Supporting Information may be found in the online version of this article.

etc_735_sm_SupplTabS1.doc61KSupplementary Table S1. Carbon distribution in different regions (ppm) of the 13C nuclear magnetic resonance spectrum for the hydrophobic fractions of HSs used in the present study.
etc_735_sm_SupplTabS2.doc57KSupplementary Table S2. The elemental compositions, atomic ratio and pKa1 of HSs used in the present study.
etc_735_sm_SupplTabS3.doc75KSupplementary Table S3. The correlation assessment of the properties of humic substances.

Please note: Wiley Blackwell is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.