Adsorption Properties and Mechanism of Attapulgite to Graphene Oxide in Aqueous Solution

Na Li,Jiyuan Fang,Cuihong Li,Haibo Kang,Wei Wang,Ping Jiang

doi:10.3390/ijerph19052793

Abstract

In order to remove toxic graphene oxide (GO) from aqueous solution, attapulgite (ATP) was used as adsorbent to recycle it by adsorption. In this paper, the effects of different pH, adsorbent mass, GO concentration, time and temperature on the adsorption of GO by attapulgite were studied, and the adsorption performance and mechanism were further explored by XRD, AFM, XPS, FTIR, TEM and SEM tests. The results show that when T = 303 K, pH = 3, and the GO concentration is 100 mg/L in 50 mL of aqueous solution, the removal rate of GO by 40 mg of attapulgite reaches 92.83%, and the partition coefficient Kd reaches 16.31. The adsorption kinetics results showed that the adsorption equilibrium was reached at 2160 min, and the adsorption process could be described by the pseudo-second-order adsorption equation, indicating that the adsorption process was accompanied by chemical adsorption and physical adsorption. The isotherm and thermodynamic parameters show that the adsorption of GO by attapulgite is more consistent with the Langmuir isotherm model, and the reaction is a spontaneous endothermic process. The analysis shows that attapulgite is a good material for removing GO, which can provide a reference for the removal of GO in an aqueous environment.

Highlights

The presence of polar oxygen-containing functional groups on the surface of graphene oxide (GO) makes it hydrophilic, while the presence of various functional groups such as carboxyl, hydroxyl, and epoxy groups makes its affinity for pollutants in water continuously strengthened, it can be used for wastewater treatment [2]
It can be seen from the figures that the needle-shaped attapulgite surface is attached with tulle-like GO, which indicates that GO is adsorbed on the surface of attaInt
The adsorption effect of GO by attapulgite was tested under different conditions, and various characterization methods were used to systematically study its adsorption performance and mechanism

Summary

Introduction

Graphene oxide (GO) is an oxygen-containing graphene derivative. The oxygencontaining groups on the surface of GO form composite materials with ions, polymers and other materials, so it has been widely used in the fields of physics, chemistry, biology and materials science [1]. The presence of polar oxygen-containing functional groups on the surface of GO makes it hydrophilic, while the presence of various functional groups such as carboxyl, hydroxyl, and epoxy groups makes its affinity for pollutants in water continuously strengthened, it can be used for wastewater treatment [2]. For the wastewater treatment by GO, many scholars have studied it. GO can be used to remove As(III) and cephalexin in aqueous solution. It can adsorb metal ions, such as Cr(VI), U(VI), Pb(II), Co(II), etc. It can adsorb metal ions, such as Cr(VI), U(VI), Pb(II), Co(II), etc. [3–8]

Methods

Results

Conclusion