The removal of copper, cadmium and lead by rice husk ash

In this study, a major agricultural waste, rice husk ash, was used for the removal of copper, cadmium and lead and their preconcentration and separation prior to analysis by graphite furnace atomic absorption spectrometry was observed. For this purpose, rice husk was thermally treated at 300degreesC, 500degreesC and 800degreesC for 8 hrs in a muffle furnace. The effects of thermal treatment and various experimental conditions on retention and elution efficiencies of the elements studied were investigated by applying batch and column methods. All elements were nearly quantitatively (>90%) retained at pH greater than or equal to 6 with a shaking time of 10 min. Maximum lead adsorption capacity of rice husk ash heated at 300degreesC, 500degreesC and 800degreesC were 12.3, 9.7, 8.6 mg Pb/g adsorbent. The results showed that rice husk ash, especially heated at 300degreesC, could be used as an efficient and inexpensive adsorbent for the removal of some toxic heavy metals from polluted wastewaters.