环境分析化学杂志

Preparation and Characterization of Activated Carbon Produced from Oil Bean (Ugba or Ukpaka) and Snail Shell

Abstract

Abugu HO, Okoye PAC, Ajiwe VIE, Omuku PE and Umeobika UC

Two agro wastes were selected and carbonized at 600°C for 45 min and 800°C for 30 min and each was divided into three different portions. Each portion was activated with HCl, H2SO4 and H3PO4 as activating agents. The activated carbons were characterized for some important parameters such as pH, ash content, nitrogen, carbon content, sulphur, fat, fibre, protein, moisture content, carbohydrate, oxygen, hydrogen, sodium, potassium and pore volume. Wastewater from battery industry was collected and treated with the activated carbons with a view to determining the extent of the heavy metal adsorption ability. The results of the characterization shows pH range of 6.71 to 6.82, while the pore volume ranged from 3.9 × 10-5 to 2.4 × 10-5 m3/g for Oil Bean activated carbon and 8.7 × 10-6 to 6.2 × 10-6 m3/g for Snail shell activated carbon. The percentage yield of activated carbon before activation is 25.79 to 27.27 for Oil Bean and 61.85 to 86.11% for Snail shell activated carbon. FTIR results shows a surface reorganization of the activated carbon with a formation of new functional groups after chemical activation. The adsorption data generated fitted well into the Freundlich isotherm model since most values of the determination coefficient (R2) >0.500 indicating a heterogeneous adsorption of heavy metals from aqueous solution. It was observed also that those carbon activated with H3PO4 were better adsorbents in most of the activated carbons produced irrespective of the heavy metals, followed by those activated with HCl while those activated with H2SO4 were the least. The ANOVA indicates that there exist a positive significance relationship between the reliability factor (R2) and the Langmuir constants in almost all the activated carbon types produced. So also it was for Freundlich isotherm constants except few of them. This study has shown that activated carbon produced from oil Bean shell and Snail Shell can compete favourably with traditional activated carbons in treating industrial waste especially from battery industries using HCL, H2SO4 and H3PO4 as activating agents.