Adsorption Anionic dye Bed height Breakthrough time Cationic surfactant Cationic surfactants Cationics Citrus fruits Dyes Fixed bed column Fixed bed columns Mengkuang leaves Reactive Orange 16 Reactive Orange 16 dye Reactive orange 16 dye Scanning electron microscopy Yoon-Nelson model Yoon-nelson model adsorption cation detection method dye leaf area model pollutant removal surfactant wastewater wastewater treatment