Methylene Blue Adsorption using Magnetite-Modified Tea Waste Adsorbent

Methylene blue (MB) is a hazardous waste for living things and the environment. In this study, MB adsorption was carried out using tea waste as an adsorbent. To enhance the adsorption process, activation with HCl and modification with magnetite (Fe3O4) were carried out. The purpose of this study was to determine the effectiveness of using tea waste adsorbent activated and modified with Fe3O4 on methylene blue waste. Tea waste was activated with HCl and modified with Fe3O4 using the coprecipitation method. Two variations of testing were conducted, namely, the variation of pH and contact time. The adsorbent was characterized using Fourier transform infrared and scanning electron microscopy. The results showed that the optimum pH at pH 10 with an adsorption power of 98.4% and a contact time of 90 minutes with an adsorption power of 98.6%, when the adsorbent was applied directly to the methylene blue waste produced an adsorption power of 99%, and an adsorption isotherm model that was suitable using Freundlich isotherm with an R2 value of 0.9704.