Carbon: Science and Technology (Dec 2016)
Calcium Ion Removal by KMnO4 Modified Pineapple Leaf Waste Carbon Prepared from Waste of Pineapple Leaf Fiber Production Processing
Abstract
Pineapple leaf fiber waste carbon, modified with 3% KMnO4, was used for Ca2+ removal from aqueous solution. The effects of contact time, loading, water hardness, and isotherms on Ca2+ adsorption were studied. The results show that the Ca2+ ion removal by pineapple leaf fiber waste carbon could be improved by modification with KMnO4. The adsorption would reach equilibrium state at about 60 min for a water source with hardness values of 40-200 mg/dm3. Increases in total hardness (40 to 200 mg/dm3) lead to a decrease in Ca2+ ion removal efficiency (90.05% to 37.65%) and an increase in Ca2+ ion adsorption capacity at equilibrium (4.37 mg/g to 8.95 mg/g). The Ca2+ removal efficiencies increase with increasing loading of modified waste carbon. The equilibrium data were fitted well by both the Langmuir isotherm and the Freundlich isotherm. For the Langmuir isotherm model, the values of the maximum Ca2+ adsorption capacity and Langmuir constant being 2.81 mg/g and 0.9262 dm3 /g, respectively. On the other hand for the Freundlich isotherm model, the KF and n values are 1.374 dm3 (1/n) mg (1-1/n)/g and 4.671, respectively. These results indicate that modified pineapple fiber waste carbon is a material with high Ca2+ ion adsorption capacity, heterogeneity, and high affinity.
