Effect of Adding Zeolite and Biochar to Soil on Heavy Metals Adsorption by Potato in a Contaminated Soil

Heavy metals enter from human being activities into soil and food cycle and can lead to poisoning. In this research, the influence of adding poplar wood biochar, mixture biochar and zeolite on the decrease of Pb, Ni and Cd adsorption by potato was investigated. To produce biochar, a lab scale gasification reactor (850°C) was used. A random trial including 3 repetitions was conducted in a greenhouse located in Basminj, Tabriz. Additives percentages were 2, 3 and 5 wt%. The amount of Ni, Pb and Cd traits were significant at 1% probability level. The highest and lowest Pb adsorption were belonged to treatment with no additives (6.89 mg per g) and poplar biochar factor (3.85 mg per g). Compared to mixture biochar (3.31 mg per g) and zeolite (4.5 mg per g), poplar wood biochar factor (2.75 mg per g) had the lowest Ni adsorption. The second (3%) and third (5%) levels treatments of poplar biochar (2.8 and 2.05 mg per g) accompanied with the third level (5%) mixture biochar factor (2.93 mg per g) had the lowest Ni and the treatment with no additives (6.75 mg per g) had the maximum Ni. The highest Cd amount was belonged to the treatment with no additives (1.96 mg per g). Furthermore, poplar biochar factor (1.18 mg per g) included the lowest Cd amount compared to the mixture biochar (1.58 mg per g) and zeolite (1.52 mg per g). Considering all, the poplar wood biochar showed the highest decline of metal adsorption.