Enhanced Biodegradation/Photodegradation of Organophosphorus Fire Retardant Using an Integrated Method of Modified Pharmacophore Model with Molecular Dynamics and Polarizable Continuum Model

Jiawen Yang; Qing Li; Yu Li

doi:10.3390/polym12081672

Enhanced Biodegradation/Photodegradation of Organophosphorus Fire Retardant Using an Integrated Method of Modified Pharmacophore Model with Molecular Dynamics and Polarizable Continuum Model

Polymers (Basel). 2020 Jul 27;12(8):1672. doi: 10.3390/polym12081672.

Authors

Jiawen Yang^{1

2}, Qing Li^{1

2}, Yu Li^{1

2}

Affiliations

¹ The Moe Key Laboratory of Resources and Environmental Systems Optimization, North China Electric Power University, Beijing 102206, China.
² College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China.

Abstract

A comprehensive 3D-quantitative structure-activity relationship (QSAR) pharmacophore model was constructed using the values of comprehensive biodegradation/photodegradation effects of 17 organophosphorus flame retardants (OPFRs) evaluated by a normalization method to modify OPFRs with high biodegradation/photodegradation, taking tris(chloro-isopropyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCIPP)-which occur frequently in the environment, and are the most difficult to degrade as target molecules. OPFR-derivative molecules TCPP-OH shows the highest improvement in biodegradation and photodegradation (55.48% and 46.37%, respectively). On simulating the biodegradation path and photodegradation path, it is found that the energy barrier of TCPP-OH for phosphate bond cleavage is reduced by 15.73% and 52.52% compared to TCPP after modification, respectively. Finally, in order to further significantly improve its biodegradability and photodegradation, the efficiency enhancement in the biodegradation and photodegradation of TCPP-OH are analyzed under the simulated environment by molecular dynamics and polarizable continuum model, respectively. The results of molecular dynamics show that the biodegradation efficiency of the TCPP-OH increased by 75.52% compared to TCPP. The UV spectral transition energy (4.07 eV) of TCPP-OH under the influence of hydrogen peroxide solvation effect is 44.23% lower than the actual transition energy (7.29 eV) of TCPP.

Keywords: 3D-QSAR pharmacophore model; biodegradation; molecular dynamics; normalization method; organophosphorus fire retardant; photodegradation; polarizable continuum model.