Efficacy evaluation of biochar and activated carbon as carriers of bacterial inoculants in the remediation of multi-metal polluted soil

Application of appropriate organic amendments as the carriers of bacterial consortium may improve the remediation efficiency of HMs-polluted soil. A greenhouse experiment was designed and carried out to investigate the capability of biochar, and activated carbon prepared from ostrich manure and almond husk as the carriers of bacterial inoculants in the phytoremediation of a calcareous soil polluted with Pb, Ni, Cd and Zn by maize. Results showed that the application of biochar and activated carbon prepared from ostrich manure increased root (78-129%) and shoot (72.3-272%) dry weight, as compared to the control. The values of metal accumulation in both maize root and shoot were in the order of Cd>Zn>Ni>Pb. While biochar and activated carbon prepared from ostrich manure significantly increased both root and shoot metals uptake, those prepared from almond husk drastically decreased the uptake of some metals. The foremost mechanism involved in the phytoremediation of Cd, Ni and Pb was phytostabilization while that of Zn was due to the phytoextraction. Results of the present study demonstrated the effectiveness of ostrich manure-derived biochar and activated carbon as an efficient treatment in the phytoremediation of multi-metal-polluted soils and the mitigation of HMs phytotoxicity.