Adsorption Behaviors of a 2D Covalent Organic Framework Toward Pd(II) in Hydrochloric Acid Solution

. All chemical reagents used in this study such as common metal chlorides, 1,3,5-triformylphloroglucinol (Tp), and p -phenylenediamine (Pa-1) were directly purchased from Kanto Chemical Co., Inc. or FUJIFILM Wako Pure Chemical Corporation and were of analytic grade. A 50 mM of stock solution of Pd(II) were prepared by dissolving the powder in a 2 M hydrochloric acid and then diluting the solution to the required concentration using deionized water. Subsequently, 0.05 g of TpPa-1 was weighed in a 9 mL vial bottle with a screw cap and 3 mL of the prepared working solution was added. The mixture was mechanically stirred at 298 K for an exact time interval. Phase separation was conducted by using a plastic syringe and nylon net filter (20–40 µm pores). The concentration of the tested metal ions before and after adsorption were determined using an inductively coupled plasma atomic emission spectrometer (ICP-AES, Shimazu ICPS-7510). The uptake percentage ( R , Abstract In this study, a hydrochloric acid-stable 2D covalent organic framework (TpPa-1) was prepared. And its adsorption behaviors in the recovery of palladium (Pd(II)) from hydrochloric acid solution was systematically investigated under the effect of contact time, hydrochloric acid concentration, chloride ions concentration, and adsorption capacity. The adsorbed species on TpPa-1 was clarified as chloridated Pd(II) by X-ray photoelectron spectroscopy.