Filtration of triazine herbicides by polymer-clay sorbents: Coupling an experimental mechanistic approach with empirical modeling

Ido Gardi, Shlomo Nir, Yael G. Mishael*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Triazine herbicides detected in surface and groundwater pose environmental and health risks. Removal of triazine herbicides (simazine, atrazine and terbuthylazine) by polymer-clay composites was studied and modeled. Their binding by a poly 4-vinyl pyridine co styrene-montmorillonite (HPVP-CoS-MMT) composite was especially high due to specific interactions between the herbicides and polymer, mainly hydrogen bonds and π-π stacking. The binding kinetics to the composite was in the order of simazine > atrazine > terbuthylazine, which was in accord with their equilibrium Langmuir binding coefficients; 44,000, 17,500 and 16,500M-1, respectively, which correlated with herbicide accessibility to form specific interaction with the polymer. Simazine binding kinetics to the composite was significantly faster than to granulated activated carbon (GAC), reaching 93% vs 38% of the maximal adsorption within 10min, respectively. Herbicide filtration by composite columns was adequately fitted by a model which considers convection and employs Langmuir formalism for kinetics of adsorption/desorption. Filtration of simazine (10μgL-1) by composite columns (40cm long, which included 26g composite mixed with sand 1:40 (weight ratio)), was well predicted by the model with nearly 120L purified, i.e., effluent concentrations were below regulation limit (3μgL-1). Effluent concentrations from GAC columns exceeded the limit after filtering 5L. Experimental results and model predictions suggest that while GAC has a high capacity for simazine binding, the composite has higher affinity towards the herbicide and its adsorption is faster, which yields more efficient filtration by composite columns.

Original languageAmerican English
Pages (from-to)64-73
Number of pages10
JournalWater Research
Volume70
DOIs
StatePublished - 1 Mar 2015

Bibliographical note

Funding Information:
Supported by The European Commission in the framework of the Project 'Diffusion of nanotechnology based devices for water treatment and recycling – NANOWAT' (ENPI CBC MED I–B/2.1/049, Grant No. 7/1997 ).

Publisher Copyright:
© 2014 Elsevier Ltd.

Keywords

  • Competitive adsorption
  • Filtration
  • Modeling
  • Polymer-clay composites
  • Simazine
  • Triazine herbicides

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