Influence of pyrolysis temperature on the characteristics and lead(II) adsorption capacity of phosphorus-engineered poplar sawdust biochar

Abstract Phosphorus (P)–engineered biochars (BCP) were prepared via co-pyrolysis of poplar sawdust and monopotassium phosphate (KH2PO4) (10 %, w/w) at 300 ?, 500 ? 700 to evaluate their potential lead [Pb(II)] adsorption. Effects pH, contact time, initial Pb(II) concentration on the adsorption capacity investigated. The physico-chemical, morphological, porous structure, crystallinity spectroscopic characteristics pre- post-Pb-adsorbed analyzed unravel mechanism. Results showed that KH2PO4 reacted with biomass carbon form stable C–P and/or C–O–P groups in BCP, increased retention aromaticity BCP. However, addition led an adverse effect e.g. surface area produced decreased by 41.53 80.32 59.74 respectively. Adsorption experiments displayed BCP exhibited highest (qmax = 154.7 mg g?1), which was almost 6 times higher than pristine biochar 24.3 g?1). Potassium polymetaphosphate [(KPO3)n] particles attached facilitated precipitation [Pb(PO3)2]n, Pb5(PO4)3OH PbHPO4. This study thus demonstrated pyrolysis temperature enhancing removal capability P-modified for from aqueous solutions.