Asian Journal of Physical and Chemical Sciences

Water pollution is a serious issue, with industrial waste, agricultural runoff, and urban activities contaminating both surface and groundwater. Caused by the extensive application of inorganic fertilizer and animal manure, nitrate levels in water are increasing globally. Humans are exposed to nitrate through water and food, which may lead to birth defects, thyroid diseases, and cancer. While traditional methods like activated charcoal are effective, researchers continue to explore sustainable alternatives. This study investigated the potential of eggplant (Solanum melongena L.) as a biosorbent for nitrate removal compared to conventional activated charcoal. Specifically, this research aimed to determine the efficiency of eggplant-derived biosorbents in nitrate removal and evaluate the impact of varying doses and contact times on adsorption capacity. Research methods such as batch adsorption experiments, preparation of potassium nitrate solutions as simulated contaminated water, and optimization of biosorbent dosage were employed to evaluate the efficiency of eggplant-derived biosorbents in nitrate removal. The use of quantitative experimental design permitted the execution of controlled tests under well-defined conditions, increasing the scientific accuracy of the study endeavor.

Results showed that activated carbon achieved higher nitrate removal efficiency (80–90%) than eggplant biosorbents (40–50%), primarily due to its greater porosity and abundance of active functional groups. However, eggplant biosorbent demonstrated its capability as an eco-friendly alternative, with production costs approximately 65% lower than activated carbon. This affordability stems from the usage of agricultural waste, positioning eggplant biosorbents as an accessible and sustainable alternative for water treatment in resource-limited settings. Statistical analysis indicated that experimental conditions such as dose and contact time significantly influenced nitrate adsorption for both materials. Despite lower adsorption efficiency (0.08-0.2 mg/g for eggplant and 0.32-0.36 mg/g for activated carbon), eggplant biosorbents present potential as a sustainable alternative for activated carbon.  Further optimization, including chemical or thermal modifications, is recommended to enhance their performance and adsorption for broader applications.