Remediation Effect Of Vinegar Residue-Based Amendments On Chromium Contaminated Soil

It is a great challenge to remediate heavy metals pollution of soil in China and many other countries.Vinegar residue?VR?is rich in organic matter,which exhibits good physical and chemical properties.Therefore VR has great potential to remediate the soil contaminated heavy metal.In this study,we prepared vinegar residue supported nanoscale zero-valent iron?VR-nZVI?and burned it into vinegar residue biochar?VRB?,then utilizing the indoor simulation experiments,the optimal modification method of materials would be confirmed.By extrusion granulation process,the best recipe under different kinds and different percentage binder was compared and the effect of particle on Cr contaminated soil was studied.The results were as follows:?1?Through the soil column leaching experiments,the effect of three different amendments on soil basic properties,the content of different valence of chromium and the content of available chromium was compared.The results indicated that VR has best effect that increases the soil organic matter content and the cation exchange capacity and decreases the redox potential and the pH.VR has positive effects to increase the reduction and fixation efficiency of Cr???and also decrease the available chromium in soil.?2?The indoor simulation experiments indicated that VR-nZVI?nZVI loading 5%?is the optimal modification method,the particle has more functional groups,greater specific surface area and better stability than nZVI.When the soil was treated with VR-nZVI for 15 days,the leaching efficiency of Cr?VI?and Cr_totalotal was significantly reduced and exchangeable Cr and carbonate-bound was almost converted to Fe-Mn oxide-bound and organic matter-bound.VR-nZVI could effectively improve soil physical and chemical properties and reduce the leachability of Fe caused by nZVI.?3?For vinegar residue-based materials,by extrusion granulation process,the best recipe under different kinds and different percentage binder is compared and the effect of particle on Cr contaminated soil was studied.The results indicated that A3 particle is the best granulation formula.When the soil was treated with A3 for 30 days,the leaching efficiency of Cr was significantly reduced and exchangeable Cr was almost converted to Fe-Mn oxide-bound and residual-bound.Soil redox potential was decreased,which increased the organic matter content,the cation exchange capacity and the pH.With the increase of A3 particle addition,the leaching efficiency of Cr and exchangeable Cr was significantly reduced and 2%A3 particle has great effect on low concentration Cr contaminated soil.