Next Article in Journal
Increase and Spatial Variation in Soil Infiltration Rates Associated with Fibrous and Tap Tree Roots
Previous Article in Journal
Correction: Harding, S.F., et al. Experimental Observation of Inertial Particles through Idealized Hydroturbine Distributor Geometry. Water 2019, 11, 471
Open AccessArticle

Assessment of the Rheological Behavior of Polymer–Oxidant Mixtures and the Influence of the Groundwater Environment on Their Properties

Key Laboratory for Water and Sediment Sciences of Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China
*
Author to whom correspondence should be addressed.
Water 2019, 11(8), 1698; https://doi.org/10.3390/w11081698
Received: 5 May 2019 / Revised: 25 July 2019 / Accepted: 13 August 2019 / Published: 16 August 2019
(This article belongs to the Section Water Quality and Ecosystems)
Shear-thinning polymers have been introduced to contaminant remediation in the subsurface as a mobility control method applied to mitigate the inefficient delivery of remedial agents caused by geological heterogeneity. Laboratory experiments have been conducted to assess the compatibility of polymers (xanthan and hydrolyzed polyacrylamide (HPAM)) and oxidants (KMnO4 and Na2S2O8) through quantitative evaluation of the viscosity maintenance, shear-thinning performance, and oxidant consumption. The mechanism that causes viscosity loss and the influence of the groundwater environment on the mixture viscosity were also explored. The xanthan–KMnO4 mixture exhibited the best performance in both viscosity retention and shear-thinning behavior with retention rates higher than 75% and 73.5%, respectively. Furthermore, the results indicated that xanthan gum has a high resistance to MnO4 and that K+ plays a leading role in its viscosity reduction, while HPAM is much more sensitive to MnO4. The viscosity responses of the two polymers to Na2S2O8 and NaCl were almost consistent with that of KMnO4; salt ions displayed an instantaneous effect on the solution’s viscosity, while the oxide ions could cause the solution’s viscosity to decrease continuously with time. Since xanthan exhibited acceptable oxidant consumption as well, xanthan–KMnO4 is considered to be the optimal combination. In addition, the results implied that the effects of salt ions and the water pH on the mixture solution could be acceptable. In the 2D tank test, it was found that when xanthan gum was introduced, the sweeping efficiency of the oxidant in the low-permeability zone was increased from 28.2% to 100%. These findings demonstrated the feasibility of using a xanthan–KMnO4 mixture for actual site remediation. View Full-Text
Keywords: polymer; solution viscosity; shear-thinning behavior; compatibility; groundwater environment; aquifer; contaminant hydrogeology polymer; solution viscosity; shear-thinning behavior; compatibility; groundwater environment; aquifer; contaminant hydrogeology
Show Figures

Graphical abstract

MDPI and ACS Style

Xu, Q.; Chen, J.; Song, X. Assessment of the Rheological Behavior of Polymer–Oxidant Mixtures and the Influence of the Groundwater Environment on Their Properties. Water 2019, 11, 1698.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map

1
Back to TopTop