Investigation of nickel removal using poly(amidoamine) generation 4 dendrimer (PAMAM G4) from aqueous solutions

Dendrimers are branched molecules that have medical, pharmaceutical, and environmental applications. Dendrimers of polyamidoamine (PAMAM) with functional groups of hydroxyl and amine are useful for making complex of heavy metals. The aim of this experimental study is to utilize dendrimer PAMAM G4 in removing nickel. FTIR and DLS analyses were conducted for determining the structure of the dendrimer. The efficiency of the process was examined under different conditions including different pHs (3, 7, 11), the concentration of the dendrimer adsorbent (0.5-2.5 g/L), the nickel concentration (5-25 mg/L), and different reaction times (5-60 min). The data analysis were carried out using with SPSS. With the increase in the reaction time at constant values of the dendrimer (1g/L), the nickel removal (C= 20 mg/L), at the pHs of 3, 7, and 11 increased from 7 to 18.5, from 45 to 69, and from 54 to 73, respectively. With the increase in the concentration of nickel from 5 to 25 mg/L, the removal efficiency at pH=11 decreased from 97 to 59%. The optimal value of the dendrimer for removing nickel was obtained as 1.5 g/L. The adsorption reaction followed Freundlich isotherm (R 2 =0.95). Through optimizing different conditions it is possible to use this adsorbent as a method with suitable effectiveness in removing heavy metals including nickel from industrial wastewaters.