Investigation of the Role of Copper Species-Modified Active Carbon by Low-Temperature Roasting on the Improvement of Arsine Adsorption

Abstract

Traditional adsorbents undershot the expectations for arsine (AsH ₃) removal under low-temperature operation conditions in the industry. In this study, the copper (Cu) precursor was used to modify activated carbon and yield novel adsorbents by low-temperature roasting for high-efficiency removal of AsH ₃. The best conditions were determined as impregnation with 2 mol/L Cu(NO ₃) ₂ adsorbent and roasting at 180 °C. At a reaction temperature of 40 °C and an oxygen content of 1%, the AsH ₃ removal efficiency reached over 90% and lasted for 40 h and the best capacity of 369.6 mg/g was obtained with the Cu/Ac adsorbent. The characterization results showed the decomposition of Cu(NO ₃) ₂ during the low-temperature roasting process to form surface functional groups. The formation of the important intermediate Cu ₂(NO ₃)(OH) ₃ in the decomposition of Cu(NO ₃) ₂ into CuO plays a role in the good regeneration performance of the Cu/Ac adsorbent using water washing and the gas regeneration method. The results of in situ diffuse reflectance infrared Fourier transform spectroscopy combined with X-ray photoelectron spectroscopy demonstrated that the interaction of trace oxygen with Lewis (L) acid sites increased chemisorbed oxygen by 17.34%, significantly promoting the spontaneity of AsH ₃ oxidation reaction. These results provide a friendly economic method with industrial processes practical for AsH ₃ removal.