Issue 6, 2022

Colloidal stabilities and deposition behaviors of chromium (hydr)oxides in the presence of dissolved organic matters: role of coprecipitation and adsorption

Abstract

Cr (hydr)oxide colloids are regarded as insoluble products of toxic Cr(VI) during the long-term remediation process. However, dissolved organic matters (DOMs) may significantly alter the fate and mobility of Cr (hydr)oxide colloids and pose the risk of Cr(VI) secondary release. In this study, we evaluated the impacts of sediment leaching organic matters (SLOMs) on the stabilities and deposition behaviors of Cr (hydr)oxide colloids by time-resolved dynamic light scattering (DLS) and quartz crystal microbalance with dissipation (QCM-D) techniques. The results indicated that in the presence of SLOMs, the colloidal size of Cr hydroxides (i.e., Cr(OH)3) increased over time due to the formation of coprecipitates with aromatic compounds containing oxygenated groups. In contrast, the SLOMs were largely adsorbed onto Cr oxide (i.e., Cr2O3 and Cr2CuO4) surfaces via non-specific interactions and disaggregated these colloids due to charge accumulation and steric effects. As a result, Cr(OH)3 sequesters a higher content of organic molecules than Cr2O3 and Cr2CuO4. Such differences in the association mechanism of Cr (hydr)oxides with SLOMs resulted in different deposition behaviors. The deposition of Cr(OH)3 on the silica surface in the presence of SLOMs depended on heterogeneous coprecipitation, which led to a higher deposition rate and mass under a higher SLOM loading. Heterogeneous coprecipitation of Cr(OH)3 and SLOMs on the silica surface led to initially irreversible deposition and compact layer nature. However, the deposition of Cr oxides in the presence of SLOMs was reversible and only relevant to their colloidal stabilities and surface charges that relied on surface adsorption of organic molecules. This study highlighted the importance of crystal forms for evaluating the fate and mobility of Cr (hydr)oxides in the presence of DOMs and potential environmental risks of long-term Cr-contamination remediation.

Graphical abstract: Colloidal stabilities and deposition behaviors of chromium (hydr)oxides in the presence of dissolved organic matters: role of coprecipitation and adsorption

Supplementary files

Article information

Article type
Paper
Submitted
13 फरवरी 2022
Accepted
07 मई 2022
First published
24 मई 2022

Environ. Sci.: Nano, 2022,9, 2207-2219

Colloidal stabilities and deposition behaviors of chromium (hydr)oxides in the presence of dissolved organic matters: role of coprecipitation and adsorption

S. Zhu, Y. Mo, J. Xing, W. Luo, C. Jin and R. Qiu, Environ. Sci.: Nano, 2022, 9, 2207 DOI: 10.1039/D2EN00136E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements