(214r) Molecular Dynamics Simulation of Dual Polyelectrolyte Coagulation With Natural Organic Matters in Aqueous System | AIChE

(214r) Molecular Dynamics Simulation of Dual Polyelectrolyte Coagulation With Natural Organic Matters in Aqueous System



Molecular Dynamic Simulation of Dual Polyelectrolyte
Coagulation

with Natural Organic Matters in Aqueous System

Yoon Jung Choi,a Hyemin Lee,a Jiwon Jung,a Sang Hyuck Parkb and Seung Soon Janga

a
School of Materials Science and Engineering, Georgia Institute of Technology,
771 Ferst Drive, Atlanta, GA 30332-0245

b
School of Science & Technology, Georgia Gwinnett College, 1000 University
Center Lane, Lawrenceville, GA 30043

Abstract

In this research, water treatment using
dual-coagulants is examined. Through Molecular Dynamics (MD) simulation, the
coagulation process with natural organic matter (NOM) is studied and analyzed at
molecular level. Two of polyelectrolytes, Polydiallyldimethylammonium chloride (PDADMAC)
and Polyacrylic Acid (PA), are used as two coagulants.
Those dual-coagulants are simulated with Humic Acid trimer with Temple-Northeastern-Birmingham (TNB) model.
During the simulation, PDADMAC forms complexes with NOM in water phase, which
are then further coagulated and flocculated with the secondary polyelectrolyte of
the opposite charge. This simulation with two coagulants and NOM was
investigated under various conditions of different solvent, ionic strength, and
molecular weight of polyelectrolytes. Throughout the extensive simulation and
analysis, it was found that the binding of PDADMAC with NOM is mainly due to
electrostatic binding. It was also found that, even after the PDADMAC
aggregates with NOMs, PDADMAC can still interact with PA through electrostatic
interaction.