Activated Carbon from Sugarcane Bagasse: A Low-Cost Approach towards Cr(VI) Removal from Wastewater.

The potential of pretreated sugarcane bagasse (SCB) as a low-cost and renewable source to yield activated carbon (AC) for chromate CrO₄²⁻ removal from an aqueous solution has been investigated. Raw sugarcane bagasse was pretreated with H₂SO₄, H₃PO₄, HCl, HNO₃, KOH, NaOH, or ZnCl₂ before carbonization at 700 °C. Only pretreatments with H₂SO₄ and KOH yield clean AC powders, while the other powders still contain non-carbonaceous components. The point of zero charge for ACs obtained from SCB pretreated with H₂SO₄ and KOH is 7.71 and 2.62, respectively. Batch equilibrium studies show that the most effective conditions for chromate removal are a low pH (i.e., below 3) where >96% of the chromate is removed from the aqueous solution. [ABSTRACT FROM AUTHOR]