DEVELOPMENT OF ACTIVATED CARBON FROM PANDANUS SENDERI STEM FOR THE REMOVAL OF Pb2+ AND Ni2+ FROM WASTEWATER

Abstract

The released of hazardous and toxic elements like heavy metals from industries into the hydrosphere like oceans, rivers, lakes are a major concern in environment. Natural agents have high adsorption capacities for divalent metal ions. Pandanus is a natural adsorbent and in comparison with others and its availability in Nigeria is cost effective. In this study, the adsorption of heavy metal ions (Pb2+ and Ni2+) from sewage wastewater which might occur by environmental contaminant in polluted underground water was investigated in batch condition. Adsorbents was prepared from pandanus senderi stem plant, carbonized at 600 oC and impregnated with 1M NaOH and 1M H3PO4 at 600 oC in a muffle furnace for 3 hours. The resultant products were analysed using Fourier Transform Infrared and Scanning Electron Microscope Energy Dispersive X-ray, and were also tested to adsorb the heavy metal ions in wastewater at varying pH, dosages, contact time and temperature. The Isotherm, kinetic and thermodynamic studies were carried out on the adsorbents. The Fourier Transform Infrared (FTIR) spectrum identified the present of hydroxyl, carbonyl, carbonxyl and lactone. The Scanning Electron Microscope Energy Dispersive X-ray (SEM/EDX) indicated that phosphoric acid particle activated carbon (H3PO4-PAC) has more carbon content of weight concentration (86.38 g) than sodium hydroxide particle activated carbon (NaOH-PAC) (84.42 g) and control activated carbon (CAC) (82.51 g) and the pandanus senderi stem carbon contain minerals like calcium, silver, potassium, silicon, phosphorus, aluminum, magnesium and sodium. The adsorption capacity and metal removal percentage was computed and recorded at various parameters (pH, contact time, dosage and temperature). In this study, the optimum value of pH to Pb2+ and Ni2+ at 10.197 and 0.4013 mg/g adsorption capacity was 4. The percentage removal for Pb2+ increased from 40 to 58% for pH increase from 2.0 to 4.0 while Ni2+ increase from 14.4 to 16.1 % for pH increase from 2 to 4. Metal removal for dosage was observed from 0.2 to 0.6 g for Pb2+ and decrement was observed in Ni2+. When compared (R2) values, experimental and predicted value, second order fitted the adsorption. By studying the entropy, enthalpy and mean free energy, Thermodynamic proved the adsorption process are spontaneous and endothermic in nature. It was recommended adsorption column study should be carried out and other chemicals order than NaOH and H3PO4 should be used to improve the efficiency. Nevertheless, other heavy metal ions should be used for adsorption studies using pandanus senderi adsorbent.