Magnetized orange peel: A realistic approach for methylene blue removal

Abstract

Though the utilization of agricultural wastes as biosorbent has demonstrated promising results in wastewater treatment, researches on magnetized biosorbent is still limited up to now. The conventional filtration and centrifugation are commonly associated with the drawbacks of long operation hours and high energy consumption. Therefore, development of magnetized biosorbent that removes the pollutant effectively and can be recovered from treated solution in shorter time offers an interesting solution. In this research, the performance of three types of orange peel adsorbent for methylene blue (MB) removal namely, untreated orange peel (UOP), chemically treated orange peel (COP), and magnetized orange peel (MOP) was compared. Adsorption results revealed that the MB percentage removal using UOP, COP, and MOP was 92.73%, 97.86% and 91.45%, respectively. The adsorption process using MOP was then further studied as a function of pH (2–12), solid to liquid ratio (1:25–1:100), temperature (30–60 °C), contact time (20–180 min) and initial MB concentration (50–250 mg/L). The highest removal percentage for MB could be achieved at pH 8, solid to liquid ratio of 1:25, temperature of 40 °C, initial MB concentration of 50 mg/L, and equilibrium time of 40 min. The kinetic study demonstrated that Langmuir adsorption isotherm model best represented the adsorption results with the maximum monolayer adsorption capacity of 40 mg/g. The findings in this research are suggesting MOP as an inexpensive biosorbent that is effective for MB dye removal in a more realistic biosorption system.