Efficient palladium ion adsorption and catalyst preparation from pharmaceutical wastewater using amino-functionalized Ti3C2

Abstract

This paper reports the recovery and reuse of Pd ions from pharmaceutical wastewater using amino-modified Ti₃C₂. Ti₃C₂–NH₂ was synthesized by modifying (3-aminopropyl)triethoxysilane and the successful substitution of some surface functional groups of Ti₃C₂; the decrease in material thickness was verified by characterization. This study revealed that the presence of amino groups significantly enhanced the Pd(II) adsorption capacity of Ti₃C₂. The effects of the adsorbent material, adsorbent dosage, pH, initial concentration of Pd ions, presence of competing cations, and contact time on the adsorption performance were investigated. The maximum adsorption capacity of 20 mg of Ti₃C₂–NH₂ was 986.65 mg/g in 100 ml of a Pd-ion solution with an initial concentration of 200 mg/l at pH 3. A pseudo-second-order kinetic model fitted well with the experimentally obtained rate data, indicating that the main mode of Pd-ion removal by Ti₃C₂–NH₂ was via chemical reduction. Finally, the catalyst exhibited excellent performances during the photocatalytic and Suzuki coupling reactions with yields of 81 % and 95 %, respectively. The results demonstrated that Ti₃C₂–NH₂ is an excellent material for adsorbing Pd ions and can effectively recycle these ions from pharmaceutical wastewater.