Removal of zinc from wastewater using orange, pineapple and pomegranate peels

Abstract

The aim of this study was to produce a low-cost adsorbent to remove zinc from wastewater using orange, pineapple and pomegranate peels that had been carbonized by microwave and chemical activated using ZnCl2 and H2SO4. Effects of the fruit type, microwave processing time, activating agent type and adsorption contact time on the optimum adsorption efficiency were investigated. Characterization of the dried peels was done using thermogravimetry/differential thermal analysis, Fourier transform infrared spectroscopy and scanning electron microscopy devices. The dried orange, pineapple and pomegranate peels were subjected to 800 W microwave power for 1 to 4 min. The products obtained were characterized by FT-IR and SEM analyses. The zinc extraction efficiency of the produced activated carbons was determined using a UV spectrophotometer. When ZnCl2 was used, maximum zinc adsorption capacity of the orange peel was 37.08 mg/g for 2 h, pomegranate peel was 35.66 mg/g and pineapple peel was 37.23 mg/g for 4 h. When H2SO4 was used, maximum zinc adsorption capacity of pomegranate peel was 37.17 mg/g for 2 h and orange peel was 37.64 mg/g, pineapple peels were 36.99 mg/g for 4 h at 20 degrees C when the initial concentration of zinc was 40 mg/L and the constant biosorbent dosage was 0.25 g/L. The best result for the 3 fruit peels was obtained from activated carbons, which were microwaved at 800 W for 4 min. As a result, it was observed that environmentally friendly and cost-effective activated carbon could be successfully produced for use in zinc adsorption from wastewater.