Amir Hossein Baghaie
1* 
1 Department of Soil Science, Arak Branch, Islamic Azad University, Arak, Iran.
Abstract
Removal of heavy metals from industrial effluents is one of the most important issues in environmental research. This study was done to investigate the adsorption effect of multiwall carbon nanotubes (MWNTs) and nano zinc oxide (ZnO) on the decrease of chromium (Cr) and cadmium (Cd) concentration in wheat that was inoculated with Piriformospora indica and irrigated with plating industry wastewater. Treatments consisted of applying MWCNs (0 and 0.5% (W/W)) and nano ZnO (0 and 1.5% (W/W)) in the soil irrigated with the plating industry wastewater under the cultivation of wheat inoculated with P. indica. This study was done as a factorial experiment in a completely randomized block design in three replications. After 90 days, plants were harvested and the concentration of Cd and Cr in the plant was measured using atomic absorption spectroscopy. The use of MWCNs had a significant effect on the increase of cation exchangeable capacity of the soil. The application of 0.5% (W/W) MWCNs in the soil irrigated with wastewater significantly decreased the soil Cd concentration by 11.7%, while the plant biomass was increased by 13.4%. In addition, applying nano ZnO (1.5% (W/W)) significantly decreased the negative effect of heavy metal toxicity that can be related to the role of nano ZnO in improving soil sorption properties. However, the interaction effect of Zn and Cd cannot be ignored. The results of this study showed that applying MWCNs and nano ZnO has a significant effect on the decrease of phytoremediation efficiency in soil irrigated with plating industry wastewater. However, the type and the amount of heavy metals in wastewater cannot be ignored.