Removal of heavy metals from model wastewater by using polybenzoxazine aerogel

Our study made use of polybenzoxazine aerogel as a chelating polymer. The results indicated that the removal of metal ions was in the following order: Sn2+ > Cu2+ > Fe2+ > Pb2+ > Ni2+ > Cd2+ > Cr2+, which was in accordance with the Irving–Williams rule. Additionally, the amount of metal ions removed depended on the amount of absorbent and sorption time. As expected, the maximum adsorption capacity of mixed-metal solutions was lower than that of single-metal solutions for all types of metals at the same conditions. The results obtained from the isotherm studies showed that the experimental data for the removal of heavy metal ions were in agreement with the Langmuir isotherm model. Furthermore, the desorption process was shown to be a function of pH, type of solution, and temperature.