摘要
The surface functional layer of biochar promotes lanthanum dispersion. • Lanthanum-loaded biochar adsorbed 63.5 mg P·g −1 of phosphate within 1 min. • Phosphate in the fixed-bed effluent kept below 0.2 mg P·L −1 . • Lanthanum raised phosphate selectivity over nitrate and sulfate by 14 and 32 times. • Molecular dynamics simulations show lanthanum boosting phosphate dehydration and diffusion. Metal-doped biochar is a promising phosphate adsorbent for mitigating phosphate-driven eutrophication and valorizing biomass, but its adsorption performance, selectivity and stability are strongly governed by the biochar-metal structure. Herein, the biochar was embedded into carbon nanofiber’ networks to construct a self-supporting biochar-carbon nanofiber framework (C-ACF). The C-ACF was first functionalized with an amine-rich HCCP-PEI polymer layer to obtain PCP@C-ACF, which was then used to anchor highly dispersed La species, yielding the performant La-loaded adsorbent PCP-La@C-ACF. Expectantly, PCP-La@C-ACF exhibited outstanding phosphate adsorption kinetics and selectivity, achieving phosphate uptake of 63.5 mg P·g −1 within 1 min (9.3-fold that of La(OH) 3 ) and an equilibrium capacity of 93.9 mg P·g −1 , along with broad pH tolerance and marked reusability. Under fixed-bed operation, PCP-La@C-ACF maintained the effluent phosphate concentration below 0.2 mg P·L −1 (removal rate > 99.4%). Owing to the loaded La species, markedly improved phosphate selectivity under high concentrations of Cl − , NO 3 – , and SO 4 2− was achieved, with selectivity coefficients against NO 3 – and SO 4 2− being 14- and 32-fold higher than La-free PCP@C-ACF. Molecular dynamics simulations rationalize that such dispersed La species enhance adsorption selectivity/rate by promoting phosphate dehydration and improving interfacial diffusion efficiency. Download: Download high-res image (179KB) Download: Download full-size image
危险品化学品经营许可证（带存储）