Optimization of Dyes Pollutant Adsorption Using KOH-Activated Eucalyptus Leaf Waste with Isotherm Adsorption Model

As with the rest of the production, the Batik industry hurts people's lives due to dyes. When discharged into the river, this dye will directly cause environmental pollution, one of which is the disruption of photosynthesis of aquatic plants and can cause disease for living things. Therefore, it is necessary to make efforts to overcome this. This study aims to determine the effect of adsorbent time variation and dose variation on methylene blue and malachite green adsorption. Adsorption is the absorption of solution molecules that occur on an adsorbent surface. The adsorbent used is Eucalyptus distillation leaf waste with KOH activation treatment using the Freundlich and Langmuir adsorption isotherm model. The measurement method uses UV-Vis spectrophotometry to analyze methylene blue and malachite green levels at the maximum wavelength. The results showed that the best % removal to adsorb methylene blue was 52.84% and malachite green 88.03% at a dose of 0.2 gram, and the optimum contact time to adsorb malachite green and methylene blue was 20 minutes. The adsorption Model in this study followed the Isotherm of Freundlich and Langmuir adsorption on malachite green with R2 of 0.872 and 0.612 for non-activation and 0.964 and 0.095 for KOH activation, while methylene blue obtained 0.636 and 0.143 for non-activation and 0.850 and 0.545 for KOH activation. Based on the study results, it was concluded that the distillation of Eucalyptus leaf waste is more effective in adsorbing malachite green.