Recent Progress in Carbonaceous Materials for the Nitrate Adsorption

Abstract

The use of inorganic nitrogen fertilizers in agricultural applications and oxidation of human and animal by-products, including septic discharge, has led to a considerable increase in nitrate contamination in water bodies. This excess nitrate is responsible for considerable damage to humans and biota. As a result, the removal of nitrate anions from groundwater, rivers, and lakes is critical. In most countries, the content of nitrates as an environmental quality guideline has recently been established to be less than 10 mg/L. Hence, the removal of nitrate ions from groundwater, rivers, and lakes is critical because contamination is expected to become increasingly severe in the future. Against this background, the development of an effective and sustainable treatment approach in the form of adsorption is becoming increasingly desirable. This review work specifically focuses on the effectiveness of carbonaceous materials for nitrate adsorption, with their production, modification, characterization, and morphology investigated in detail. In addition, challenges and future opportunities for applying carbonaceous materials as adsorbents for nitrate removal are also addressed. From the literature results, it has been found that there is an enhancement in the surface area through chemical activation for better nitrate adsorption. It has also been found in the literature that the maximum nitrate adsorption was on a biographene nanosheet-based wheat straw biochar at an initial nitrate concentration of 150 mg/L and a of pH of 7.17. Researchers have reported that the adsorption process with applications of carbonaceous materials is promising for the removal of the nitrate ion, but finding cost-effective, environmentally sound, and efficient adsorbents concurrently for nitrate removal from aqueous solutions remains a challenge at the industrial scale, which should be addressed in future research.