Aggregation Behavior of Dissolved Black Carbon: Implications for Vertical Mass Flux and Fractionation in Aquatic Systems

• DOI: 10.1021/acs.est.7b04232
• Publication Date: 2017-11-14T03:29:35Z
• Authors: Fanchao Xu; Chenhui Wei; Qingqing Zeng; Xuening Li; Pedro J.J. Alvarez; Qilin Li; Xiaolei Qu; Dongqiang Zhu
• Keywords: dBc; Carbon fibers

The fluvial export of dissolved black carbon (DBC) is a major land-ocean flux in the global cycle, affecting size refractory pool oceans. aggregation behavior DBC significant determinant its transport and vertical mass flux. In this study, kinetics interaction energy leached from biochar were investigated. was mainly stabilized by hydration force underwent structural compacting divalent cation solutions. Na+ Mg2+ had limited impact on colloidal stability due to strong these cations. Ca2+ Ba2+ readily destabilized forming inner-sphere complexes, reducing hydrophilicity. Consistently, charge reversal observed with high concentrations Ba2+. Simulated sunlight exposure led photo-oxidation DBC, increasing stability. behaved nonconservatively laboratory mixing experiments using estuary water samples aggregation/sedimentation; while model aquatic humic acid conservatively. Our results infer that there possible fractionation organic matter estuarine systems, which have been overlooked efforts determine budgets associated climate change implications.