ADSORPTION OF Fe(II) AND Mn(II) FROM OGUN RIVER USING ACTIVATED CARBON PREPARED FROM PLANTAIN PEEL

Abstract

Discharge of untreated industrial effluents containing heavy metals is hazardous to the environment as they are highly toxic, accumulates in food chain and persistent in nature. Hence, their removal from water is a substantial step in the protection of the environment and human health. This research compares and explores the potency of activated and carbonized (un-activated) plantain peel in the adsorption of Fe(II) and Mn(II) contamination from Ogun river catchment at Agboyi Ketu (which is an important bird nesting, fishing and drinking water source) using fixed bed column adsorption method. Atomic Absorption Spectroscopy (AAS) of the raw water sample show that it contains 1.1 mg/l and 3.1 mg/l of manganese (Mn2+) and iron (Fe2+) respectively. Plantain peels were collected from a local plantain chip factory as wastes from Ibule, Akure, Ondo state, washed, sundried, cut into small sizes of about 2x2 cm, dehydrated in oven at 110oC, crushed with mortar and pestle then sieved using 500 μm sieve then carbonized using an electric furnace at 500oC for 1 hour. 500g of the carbonized plantain peel was weighed into a beaker and soaked in 500 ml of H3PO4 for 48 hours then dried in microwave at 300W for 5 minutes to produce the activated adsorbent. The adsorption study was conducted in a column of 50 cm height, 2 cm inner diameter in which the raw water samples at a constant flow rate of 3.33 ml/minute passed under gravity through each adsorbent at constant bed depth of 30 cm. Characterization of the adsorbent was done using Fourier Transform infrared Spectroscopy (FTIR) which revealed absorbance peaks of aldehyde, amide, alkyl, hydroxyl and carboxylic functional group. The adsorption of Fe (II) using carbonized plantain peel showed that the break through time (𝑡𝑏), and exhaust time (𝑡𝑒) were 28 and 86 minutes respectively. The time required for the formation of adsorbent zone (θƒ), was estimated as 27.24 minutes. Quantity of solute removed from the solution in the adsorption zone (U) was found to be 314.89 g. The adsorption rate constant (K) was found out as 1.58 L/mg hour and adsorption capacity coefficient (N) as 1.48 mg/L While in the use of activated plantain peel, 𝑡𝑏= 81 minutes, 𝑡𝑒= 114 minutes, θƒ = 27.12 minutes, U = 371.7g, K= 1.57 L/mg hour and N= 3.1 mg/L. In the adsorption of manganese using carbonized plantain peel, 𝑡𝑏= 67 minutes , 𝑡𝑒= 123 minutes, θƒ = 30.56 minutes, U = 90.65g , K= 5.06 L/mg hour and N= 1.74 mg/L while the result of activated plantain peel are; 𝑡𝑏= 145 minutes , 𝑡𝑒= 219 minutes, θƒ = 30.29 minutes, U = 159.9 g , K= 3.73 L/mg hour and N=1.74 mg/L. Both adsorbent were found to be effective whereas activated plantain peel has relatively higher adsorption capacity and can be applied for water treatment.