Engineered basil seed hydrogel for eco-conscious adsorption of anionic contaminants in groundwater

This investigation endeavours to address the presence of arsenic and fluoride ions, common contaminants in groundwater, by utilizing basil seeds (BS) derived from Ocimum basilicum L. as a natural means for water purification. In this research, BS were modified with ferric ions (FBS) and aluminium ions (ABS) to facilitate the adsorptive removal of arsenic and fluoride ions, respectively. Adsorption experiments were conducted through batch adsorption and the teabag dip methods. The modified biosorbents were characterized using a stereomicroscope, FE-SEM, and TGA analyses to ascertain their morphology and thermal stability. The study aimed to elucidate the impact of arsenic and fluoride ion concentration, equilibration time, temperature variations, and pH levels on adsorption phenomena. The adsorption isotherm data conformed well to the Langmuir adsorption model, while kinetics adhered to the pseudo-second-order reaction model. Notably, rapid removal of contaminants was observed, with a maximum adsorption capacity of 20 mg/g within 10 min for fluoride ions and 3.03 mg/g within 20 min for arsenic ions. The results indicate that chemisorption mechanisms primarily govern the removal of contaminants. These findings highlight the efficacy of locally sourced basil seeds as a promising low-cost biomaterial for the efficient removal of arsenic and fluoride ions from drinking water, with demonstrated potential for real-time application.