Preparation of Sodium Pyrophosphate Modified Municipal Sludge Biochar for the Cu Adsorption in Aqueous Solution

Abstract

In this work, sodium pyrophosphate (SP) was used as a modifier to prepare the sodium pyrophosphate modified municipal sludge biochar (SP-MSB) for effectively adsorbing Cu in aqueous solution. Four modification factors, i.e., SP concentration factor, impregnation time factor, impregnation solid-liquid ratio factor, and impregnation temperature factor, were investigated to explore the suitable modification condition for the preparation of SP-MSB. In addition, the Cu adsorption efficiencies of the SP-MSB under the suitable modification condition and the unmodified municipal sludge biochar (MSB) were preliminarily evaluated. The results showed that the suitable modification condition for the preparation of SP-MSB was SP concentration of 60 g/L, impregnation time of 10 h, impregnation solid-liquid ratio of 1:30, and impregnation temperature of 25 °C. The Cu adsorption capability of the SP-MSB was 6.37 times than that of MSB, indicating that the SP-MSB can be used as an alternative adsorbent to adsorb Cu in aqueous solution.