Physicochemical Characterization and Adsorptive Performance of Agro-based Adsorbent for Methylene Blue Removal from Aqueous Solution

The discharge of synthetic dyes into aquatic systems poses a persistent environmental challenge because of their recalcitrance and potential impacts on water quality and human health. In this study, jujube seed-derived adsorbent (JJS) was developed and evaluated for the removal of methylene blue (MB) from aqueous media. The adsorbent exhibited favorable physicochemical properties, including a carbon yield of 72.42 %, bulk density of 0.59g/cm-3, pH of 8.61, iodine number of 556.89 mg/g-1, moisture content of 7.62 %, ash content of 1.40 % volatile matter of 0.60, and a point of zero charge (pHpzc) of 7.0. Brunauer-Emmett-Teller (BET) analysis revealed a high specific of 940.650 m2/g-1, indicating adsorptive surface. Fourier-Transform Infrared spectroscopy (FT-IR) identified a pronounced hydroxyl (-OH) band at 3417.98 cm-1, suggesting the contribution of oxygen containing surface functionalities of MB uptake. Scanning Electron Microscopy (SEM) revealed a high porous morphology, while Energy Dispersive Xay Spectroscopy (EDX) confirmed carbon (83.08 %), oxygen (15.66 %), and calcium (0.69 %) as the major detected elements. The JJS adsorbent demonstrated consistently high MB removal efficiencies over three treatment cycles, achieving 96.04 %, 97.60 % and 99.84 % removal in cycles 1, 2, and 3 respectively. These results demonstrate that jujube seed-derived biomass possesses favorable physicochemical and structural characteristics for dye adsorption and can serve as a promising low-cost and environmentally sustainable precursor for the development of adsorbents for MB-contaminated aqueous effluents, particularly wastewater associated with tie-and-dye activities.