Deciphering the effect of citric acid on arsenic adsorption with phosphorene in aqueous solution

This paper presents the first attempt to explore the potential of phosphorene as an adsorbent for arsenic [AS(III) and As(V)] removal under competition adsorption with citric acid (CA). In this study, the phosphorene was prepared by the exfoliation method. Results showed that CA reduced As(III) adsorption due to the lower stability constant of organic-As(III) complexes. The adsorption capacity with phosphorene was enhanced with a decrease in the initial concentration of CA. The adsorption rates for As(III) and As(V) were 0.033 and 0.069 min(- 1), respectively, according to kinetics analysis. The maximum adsorption capacity obtained using the Langmuir model was 8.9 mg g(- 1) for As(III) at pH 7 with 0.1 mM CA addition, and the As(V) adsorption capacity of phosphorene was 20 mg g(- 1).