A Cylindrical Model Of Pyrite Oxidation In Coastal Acidic Soils

Detailed analyses of acid soils in coastal areas of (New South Wales, NSW) indicate that (FeS2) oxidation occurs very close to narrow root channels. The root channels have been caused by extant organic activity and allow oxygen to diffuse through to pyritic layers. From the wall of the root channels in the pyritic layers, oxygen diffuses laterally into the acid soil matrix oxidizing the pyrite present. Such a simultaneous process can be modeled cylindrically. In this paper, a new cylindrical model is developed and solved using approximations to pyrite consumption kinetics. An adapted PDE2D code based on finite element methods is used to solve a linear approximation and Michaelis-Menten uptake kinetics. Pyrite oxidation produces acid in the soil matrix that is subsequently transported to the estaurine waterways, following high rainfall sessions causing a number of environmental disasters. An estimate of the new acid produced in the field is often required before remediation work is possible, and such an estimate may be determined easily using the new model. The result of pyrite oxidation based on the cylindrical approach demonstrate that the new model can accurately predict pyrite oxidation and acid production. The total acid production calculated using the new approach was found to be close to the actual field amount at the Berry site. The new results also compare well with the predictions made by the previous models developed for the Berry site.