Background and Purpose: Phytoremediation efficiency of heavy metals is an important factor in environmental studies. This study was conducted to investigate the effect of multi-walled carbon nanotubes (MWCNTs), zeolite, and P.indica on bio-degradation of mazut in a soil treated with Cd and mazut.
Materials and Methods: Treatments consisted of applying zeolite (0, 1 and 2% (W/W)), MWCNTs (0, 1 and 2 % (W/W)) in the presence and absence of P.Indica in the Cd (0 , 5 and 10 mg/kg soil) polluted soil that was simultaneously polluted with mazut (0 and 6 % (W/W)). After 70 days, plants were harvested, and plant and soil Cd were measured using AAS. In addition, the degradation percentage of mazut in soil was determined.
Results: The addition of 2 % (W/W) MWCNTs and zeolite to the soil polluted with 6 % (W/W) mazut significantly increased the bio-degradation percentage of mazut in the soil by 11.3%. For soil and plant Cd concentration, it was decreased by 10.6 and 12.8%, respectively. In addition, plant inoculation with P.indica significantly increased the biodegradation of mazut in the Cd polluted soil (10 mg Cd/kg soil) by 14.3%. Increasing soil pollution to mazut from 0 to 6 % (W/W) significantly increased the soil microbial respiration by 14.4%.
Conclusion: Based on the results, the addition of MWCNs and zeolite in the soil and plant inoculation with P.indica significantly increased the mazut bio-degradation in the soil. However, the amount and type of pollutant had a significant effect on phytoremediation efficiency.