Revealing selected groundwater contaminants, risks, and sustainable solutions for safe drinking water through pristine and modified biochar

Groundwater serves as the primary source of drinking water for nearly half of the world's population. However, it is often contaminated with heavy metals, nitrates, fluorides, chlorides, and emerging contaminants, posing risks to human health. Treating groundwater to deliver safe drinking water is crucial, and biochar has emerged as a promising solution. While pristine biochar has proven to be an effective adsorbent in terms of performance, cost and regeneration capabilities, various studies have reported modification methods to further enhance its adsorption capacities. Although significant research has focused on efficacy of pristine and modified biochar in removing contaminants from aqueous solutions, its application for groundwater treatment remains limited. This study presents a systematic review consolidating knowledge on both pristine and modified biochar for the removal of inorganic and organic pollutants from groundwater. The review explores adsorption mechanisms, modification techniques, and the economic and environmental impacts of biochar application. It also emphasizes the need for future studies to concentrate on the interconnectivity of performance, cost, and environmental impacts of both pristine and modified biochar as well as their practical application in groundwater treatment for drinking water purposes.