Sugarcane bagasse treated with hydrous ferric oxide as a potential adsorbent for the removal of As(V) from aqueous solutions.

The mechanism of As(V) removal from aqueous solutions by means of hydrated ferric oxide (HFO)-treated sugarcane bagasse (SCB-HFO) (Saccharum officinarum L.) was investigated. Effects of different parameters, such as pH value, initial arsenic concentration, adsorbent dosage, contact time and ionic strength, on the As(V) adsorption were studied. The adsorption capacity of SCB-HFO for As(V) was found to be 22.1 mg/g under optimum conditions of pH 4, contact time 3h and temperature 22 °C. Initial As(V) concentration influenced the removal efficiency of SCB-HFO. The desorption of As(V) from the adsorbent was 17% when using 30% HCl and 85% with 1M NaOH solution. FTIR analyses evidenced two potential binding sites associated with carboxyl and hydroxyl groups which are responsible for As(V) removal. Adsorption, surface precipitation, ion exchange and complexation can be suggested as mechanisms for the As(V) removal from the solution phase onto the surface of SCB-HFO.