Molecular dynamics study of selective adsorption of PCB on activated carbon

Abstract

The selectivity of PCB adsorption from fish oil onto activated carbon (AC) was investigated by means of molecular dynamics to determine the importance of molecular planarity. PCB congeners 77 and 118 were selected for comparison purposes due to pronounced differences in mean adsorption efficiency and molecular geometry; triolein, a triacylglycerol of oleic acid (C18:1), was used as the representative fish oil component. Graphitic carbon structure was set up to serve as activated carbon model. Molecular force fields employed in the simulations combined short-range parameters from the OPLS with partial atomic charges obtained via quantum chemical calculations using DFT/B3LYP/6-31**G+ and Solvation Model 6. We modified the dihedral angle potential between the PCB aromatic rings and applied Schrödinger's Jaguar package to evaluate the required force field constants. Our complete system comprised a number of PCB molecules dissolved in triacylglycerol that overlaid and filled the pores of an AC structure. The production run of 4 ns provided strong indications that smaller pores will be conductive to better selectivity though also resulted in certain doubts concerning the the estimation and assignment of partial atomic charges on the activated carbon. The majority of PCB molecules trapped in pores were attached via cl-AC "bonding", leaving the main part of the PCB molecule free to interact with triolein. The cl-AC adsorption energy was found to surpass the energy criteria conventionally used for hydrogen bonds. Planar orientation assumed by a PCB molecule in a very energetically favored position on * Corresponding author. top of the graphite sheet clearly supported the π-cloud overlap hypothesis.

Applications of molecular modeling in the design of new insect repellents targeting the odorant binding protein of Anopheles gambiae

“…This procedure was already successfully adopted in a former work of our group and in other works in the literature. [28][29][30][31][32][33][34][35] The AgOBP 1 -ligand complexes were simulated using the GROMACS 4.0 package 25 in cubic boxes of approximately 8,214 nm 3 containing about 17,000 water molecules. These systems were minimized using the force field GROMOS96.…”

Decrease of the level of extractable polychlorinated biphenyls in soil microcosms: Influence of granular activated carbon and inoculation by natural microbial consortia

“…Technologies using activated carbon (AC) have also been proposed for treating PCBcontaminated sites (Hilber and Bucheli, 2010;Jensen et al, 2011;Ghosh et al, 2011;Gomes et al, 2013), taking advantage of the high capacity of AC to adsorb PCB congeners. The introduction of AC directly into PCB-polluted soils has proved an effective in situ stabilization technology for reducing PCB bioavailability (Vasilyeva et al, 2006(Vasilyeva et al, , 2010Hilber and Bucheli, 2010;Gomes et al, 2013).…”

Interaction of paracetamol and 125I-paracetamol with surface groups of activated carbon: theoretical and experimental study

“…In the experimental works, either commercial AC with different SG content have been used in order to correlate this content with the adsorption capacities, or designed and tested AC with different SG contents. In this regard, computational chemistry can play a major role in designing specific modifications to obtain more efficient and specific adsorbents [18,20].…”