Effect of Citric Acid on Arsenic Removal with Phosphorene and Adsorption in Solution

摘要

This first attempt study explored characteristics of prepared phosphorene materials for promising As(III) treatment. The past year has witnessed the fast growth of investigations on monolayer and few-layer black phosphorous, turned as 'phosphorene.' Same as graphene, single-layer phosphorene is flexible and can be mechanically exfoliated. In this study, the phosphorene catalysts were prepared by exfoliation method. Moreover, four kinds of arsenic concentration, including 0.5, 1, 2 and 4 ppm were tested. The effects of low molecular weight organic acid on competitive adsorption of As(III) were also investigated. The results were compared with that from single metal system. To have detailed characteristics of the morphology. The morphology and elastic strain of the composites were analyzed by transmission electron microscopy and atomic force microscopy. The height of the phosphorene is approximately 5.58nm. The profile of the phosphorene nanosheets exhibits clear edges and a thickness range of ca. 4.55-6 nm. The AFM results indicate that the large nanofilms mainly contain three- to five-layer phosphorene. The results showed that citric acid induced an increase in As(III) adsorption in solution due to the small stability constant of organic-As(III) complexes. The promotion was increased with the increase of the initial concentration of citric acid. The efficiencies of arsenic adsorption were 80%, 50%, 40%, and 20% at pH 3, 5, 7, and 9, respectively, at 25°C and phosphorene dosage of 0.1 g L~(-1). The adsorption capacity are 1.177、 1.767、 2.20 and 3.40mg g~(-1) under 15, 25, 35 and 45°C, respectively. Compared to phosphorene materials, the most appropriate rate of As(III) adsorption rate at 0.0329min~(-1) was achieved. The apparent values for Freundlich sorption capacities were 4.67 mg g~(-1) for As(III) at pH7.