Research Article
Moronkola BA, Giwa-Ajeniya AO,
Abstract
Water is one of the world’s most valuable resources, which is under constant threat due to climate change, drought, explosive population growth and waste. A wide variety of heavy metal species enters the aquatic compartment through atmospheric deposition, lixiviation of mining areas and cultivated fields, and industrial discharges. These activities follow an upward curve in response to the world’s ever growing population and its needs. Therefore, there is need to discover non-toxic adsorbent from natural source to combat the menace of water pollution. Orange peel is a non-toxic and environmentally friendly fruit, adsorbent potentials. The present study investigates the adsorption of divalent metal ions from aqueous media using unmodified orange peel as adsorbent. The orange peels for the adsorption experiment was cut, washed, dried and ground into fine powder. The powdered material was characterized using Fourier Transform Infrared (FT-IR) spectrophotometer and Scanning Electron Microscope (SEM). Determination of heavy metals adsorbed was performed on Perkin Elmer model 214 Atomic Absorption Spectrometry (AAS). The effect of pH, contact time, initial metal ion concentration and adsorbent dosage in the removal of heavy metals from aqueous media were evaluated. The Orange peel showed high metal uptake for the tested metal ions Co2+ (97.8%), Cu2+ (95.5%) and Zn2+ (97.0%). The optimum pH for Orange peel was 3, the optimum contact time for the dehydration method of the orange peel was 150 min, and the optimum adsorbent dosage for the Orange peel was 2 g while the orange peel biosorbent optimum initial metal ion concentration was 40 ppm. Adsorption data fitted well with Freundlich and Langmuir equilibrium adsorption isotherms. The maximum adsorption capacity Q value for Langmuir model for the initial metal ion concentration were in the order Cu2+>Co2+>Zn2+. Conclusively, the effective adsorbent properties displayed by the orange peels in the removal of divalent ion from aqueous media studies indicate their potentials in the treatment of water pollution.