Selective removal of cationic organic dyes from aqueous solution using dendritic fibrous nanosilica

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Developing novel adsorbents with high selectivity is crucial for the effective adsorption of diverse organic pollutants in wastewater. Dendritic fibrous nanosilica (KCC-1) was synthesized through the hydrothermal method to evaluate the impact of varying silica content (112, 170 and 224 mmol) on its adsorption capacity. The resultant KCC-1 displayed distinctly defined fibres and three-dimensional (3D) center-radial channels, resulting in large pore volumes, exceedingly high specific surface areas, and particularly accessible internal sites, which offer numerous adsorption sites. Experimental results demonstrated that varying silica moles affected particle size and specific textural properties (including surface area and pore volume) to a certain degree, with little impact on the performance. The results indicated that the synthesized KCC-1 using 170 mmol silica source exhibited superior efficiency for the selective adsorption of cationic dyes (rhodamine B and methylene blue) compared to anionic dyes (methyl orange and tartrazine) at pH 7.0. The maximum adsorption capacities for rhodamine B and methylene blue, according to the Langmuir isotherm model, were found to be 124.5 mg/g and 117.4 mg/g, respectively. The pronounced adsorption affinity for cationic dyes was attributed to the robust electrostatic interactions that occur between the adsorbent and the adsorbates. This study elucidates the extent to which reaction parameters influence the performance of KCC-1, given that their physicochemical properties are contingent with methodology and reaction parameters. The KCC-1 exhibits a remarkable ability to selectively remove dyes, indicating significant potential for the separation and recovery of dyes from real wastewater.