Superfund Research Program
Chloro-Organic Degradation by Polymer Membrane Immobilized Iron-Based Particle Systems
Project Leader: Dibakar Bhattacharyya
Grant Number: P42ES007380
Funding Period: 2000-2019
The main objective of Dr. Bhattacharyya’s project continues to be the development of new and effective methods for the dechlorination of toxic organics. Because of the presence of various chemicals (chloroethylenes to PCBs) in hazardous waste and Superfund sites, the development of both oxidative (use of hydroxy radicals) and nanotechnology-based reductive (nanosized zero-valent metals) processes is important to bring solution to various remediation problems.
Improvements to oxidative techniques for the destruction of chlorinated phenols (2,4,6-Trichlorophenol [TCP]) and PCBs have focused on the development of supported systems for a more efficient and controlled application of Fenton (free radical) chemistry for groundwater remediation. The study of reductive dechlorination technology involved the synthesis of mixed-matrix polymeric membranes containing bimetallic iron-based nanoparticles using either functionalization and ion-exchange principles or phase-inversion membrane processing. Ion-exchange membranes were prepared using both PAA (poly-acrylic acid) or Chitosan to compare the role of carboxyl (PAA) and amine (chitosan) functional groups for metal chelation during the formation of nanoparticles (20-40 nm) and the detoxification of chlorinated organics (TCE and PCBs). For the dechlorination of 2,3,2',5'-tetrachlorobiphenyl (TeCB) by PAA-bound Fe/Pd (Pd = 2wt%) nanoparticles, complete degradation of TeCB to biphenyl was achieved within 90 mins. For the dechlorination of TCE (trichloroethylene) with PAA-bound Fe/Ni (Ni = 25 wt%) nanoparticles, complete conversion of TCE to ethane was achieved within 2 hours.