Generalised mathematical model to estimate Zn, Pb, Cd, Ni, Cu, Cr and As release from contaminated estuarine sediment using pH-static leaching tests

摘要: Abstract Variations in the environmental conditions marine and estuarine environments can lead to release of elements from sediment seawater phase. The pH dependence leaching test with continuous pH-control evaluates constituents as a function pH. In this work, analysis Zn, Pb, Cd, Ni, Cu, Cr As Suances estuary (northern Spain) is performed using control at values 4, 5, 5.5, 6, 6.5 7 liquid. These pollutants present different experimental patterns over time but not all them are well fitted by previous models. Hence, generalised model time-dependent releases under these proposed. considers three reactions series: (i) oxidation reaction reduced fraction consider speciation change time, (ii) metal oxidised bulk dissolution (iii) adsorption or precipitation after element release. maximum concentration each pollutant that could be released rate coefficients parameters proposed model. for fit second order equation Using Aspen Custom Modeler software, have been estimated. A good agreement between modelled obtained. addition improving upon results models parallel, predicts mobility delay short times Cd Cu process an initial rapid (As Cr) reasonably well. provides when applied two sediments levels oxidation. obtained would useful predicting studied cases which polluted totally mixed inorganic acid-acidified semibatch tests.