chemical stabilization of some heavy metals in an artificially multi-elements contaminated soil,using rice husk biochar and coal fly ash

A greenhouse experiment hasbeen plannedfor this studyto delineate the benefits of two types of rice husk biochars (namely b300 and b600 which are prepared at 300°c and 600°c, respectvely) and coal fly ash (cfa), as soil amendments, for decreasing the amount of some heavy metals (like pb, cd, ni, cr, and cu) as well as mobility and phytoavailability in an artificially-calcareous multi-element-contaminated soil. the effect of soil amendment on heavy metals’ availability has been evaluated via sequential extraction experiment and phytoavailability of the plant. according to the results, among the studied amendments, b600 has had the highest positive effect on both dry matter yield in corn and heavy metals’availabilityreduction in post-harvest soil samples (with the exceptionofcr),compared to cfa and b300, due to the increasing specific surface area, cec, and ph that promoteheavy metals’ sorption in the soil through surface complexation and ion exchange mechanisms. evaluation of heavy metals’ chemical forms in post-harvest soil samples indicatesthat addition of amendments has significantly decreased mobility factor of heavy metals (with the exception of cr in cfa-amended soils). in general, application of three soil amendments to this polluted soil hasconsiderable effect on the reduction of heavy metals’ availability and phytoavailability.however, among the studied amendments, b600 and cfa have had the maximumand minimum effect on heavy metals’availabilityreduction, respectively.