Abstract

The aim of the present study was examination theability of different contents of kiwi shell to adsorb differenttypes (cadmium, nickel and lead) and concentrations (5, 10, 20,30, 40, 50 and 100 mgl-1) of heavy metal ions from aqueoussolutions. The kiwi shell samples were collected from gardens ofnorthern Iran, washed and grounded to assess the monometaland competitive adsorption behavior of Cd, Ni and Pb on thekiwi shell. The sum of adsorbed heavy metals on the kiwi shellcould well described using both the Freundlich (R2 between0.92 – 0.98) and Langmuir (R2 between 0.96 – 0.99) equations.All of the sorption isotherms were of the L-curve type. Resultsfrom the batch experiments show that the maximum adsorptioncapacities of the metals by the kiwi shell were in the order ofPb >> Ni > Cd based on the both monometal and competitivesystems. The distribution coefficient (kd), Freundlich capacitycoefficient (kF) and Langmuir maximum capacity (a) werehigher in monometal than in competitive system. Competitionsignificantly reduced metals k, especially for Cd and Ni. Thesorption capacity in different contents of kiwi shell was in theorder of 5 > 3 > 1 g for the metals. The total sorption amountincreased with the increasing the initial concentration of themetal; however, distribution coefficient values for each metalconcentration at both systems indicated that the kiwi shellcapacities for sorption decreased with increasing the initialconcentration of the metals.