The absorption effect and mechanism of graphene oxide removal from aqueous solution by basalt stone power

Abstract

Graphene oxide (GO) is a novel carbon material utilized extensively for diverse industrial applications. When exposed to environmental elements like sunlight and chlorination, GO can undergo a series of physical and chemical transformations, and its presence in water and the environment can endanger ecosystems. Therefore there is a need for methods that can effectively remove GO from water. Accordingly, we delve into the efficacy of basalt stone powder (BSP) as an adsorption medium for purifying aqueous solutions of GO. We examine the impact of various experimental parameters—namely pH, initial solution concentration, adsorbent mass, contact duration, and ambient temperature—on GO adsorption, employing the method of controlled variables. The adsorption efficacy is notably influenced by the pH level. At an acidic pH of 3, an initial GO concentration of 80 mg/L, an adsorbent dosage of 50 mg, and a temperature of 303 K (approximately 30 °C), the adsorption removal efficiency reaches an impressive 99 %, boasting a maximum adsorption capacity of 112 mg/g. Dynamically, the adsorption kinetics align most closely with a pseudo-first-order model, achieving equilibrium after 24 h. Thermodynamic analyses reveal that the Langmuir isotherm model most accurately describes the adsorption behavior, indicating an enhancement in BSP's adsorption capacity for GO as temperature rises. Based on thermodynamic equations, the adsorption of GO onto BSP is deduced to be a spontaneous process. Our findings illustrate BSP's considerable potential in the treatment and removal of GO from water, and therefore it may prove useful in environmental remediation efforts.

Keywords

• Basalt stone powder
• Graphene oxide
• Adsorption kinetics
• Thermodynamic analyses
• Thermodynamic equations