Unveiling the potential of Rhododendron foliage: a novel eco-friendly and cost-effective approach for cationic dye removal using in situ co-hydrothermally synthesized magnetic hydrochar

A novel environmentally friendly and cost-effective adsorbents derived via hydrothermal carbonization (HTC), designated as HC-I, HC-II, and MHC, were isolated in situ using iron precursor and alkaline medium from Rhododendron arboreum leaves (RAL) for the purpose of organic dye removal from wastewater. The materials underwent comprehensive characterization through Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS). Among the three materials, MHC exhibited notably very high efficacy in reducing contaminants, i.e., crystal violet (CV), methyl green (MG), fuchsin basic (FB), and methylene blue (MB) from waste water. Batch adsorption experiments revealed MHC’s superior performance, achieving maximum dye removal rates of 99.32% for CV, 98.496% for MG, 92.024% for FB, and 91.496% for MB, surpassing the capabilities of HC-I, HC-II besides other related materials. Moreover, its magnetic nature facilitated easy separation from the solution. This study not only presents the synthesis and characterization of the effective magnetic hydrochar material, but also underscores the potential of adsorbent materials for pollutant removal from textile effluent.