EFFICIENT REMOVAL OF CADMIUM IONS FROM AQUEOUS SOLUTIONS USING BIMETALLIC SR-CU SUPPORTED GRAPHITIC CARBON NITRIDE COMPOSITE

Abstract

The contamination of water by cadmium poses serious health and environmental risks, and the use of efficient and cost-effective adsorbents to remove Cd⁺² in aqueous media is necessary. The synthesis and evaluation of a bimetallic Sr-Cu supported graphitic carbon nitride (Sr-Cu@g-C₃N₄) composite to remove Cd⁺² in aqueous solutions is discussed here. The composite was made through a simple wet-impregnation process, which ensure evenly distributed Sr and Cu on the g- C₃N₄ surface. To investigate the effects of pH, contact time, initial metal concentration, the dosage of adsorbent and temperature, batch adsorption studies were carried out. The Sr-Cu@g-C₃N₄ was found to have a maximum adsorption capacity of 178 mg g^-1 in 30 min at pH 6 and 298 K, which was best explained by the pseudo-second-order model, indicating that chemisorption was the most dominant mechanism. The Langmuir isotherm fit the equilibrium data well, which confirmed the monolayer adsorption on a homogeneous surface. Thermodynamic studies indicated that the process is exothermic and spontaneous. The adsorbent also showed five regeneration cycles making it highly effective and thus proving to be practically reusable. In general, Sr-Cu@g-C₃N₄ is a promising, stable, and effective material to use in Cd⁺² removal during wastewater treatment.