Enhanced Phosphate Adsorption by Mg-Stirred Leaf Biochar in a Complex Water Matrix via Active MgO Facet Exposure

Abstract

In phosphate adsorption, the interaction between MgO and the carbon network in Mg-biochar is an overlooked factor that contributes to active MgO facet generation for enhancing phosphate adsorption. However, the complex water matrix adsorption mechanism underlying the adaptability of MgO-biochar and enhanced phosphate adsorption are not fully studied. Herein, Mg-stirred leaf biochar (Mg-SLBC) was prepared by the Mg-stirring modification method. Mg-SLBC possessed the highest adsorption capacity (79.28 mg g–1) to phosphate among the adsorbents. In addition, Mg-SLBC had a good performance for phosphate adsorption in a complex water matrix. Phosphate adsorption by Mg-SLBC was not affected by Cl–, NO3 –, SO4 2–, humic acid, metal ions, and Ca2+ but was inhibited by Mg2+ and HCO3 –. For long-term adsorption, Mg-SLBC could constantly adsorb phosphate to avoid phosphate accumulation (<2 mg L–1). Meanwhile, phosphate adsorption by Mg-SLBC was a spontaneous process (ΔG, −6.884 kJ mol–1), which was dominated by inner-sphere complexation. Owing to high combination between MgO and the carbon network, there were more active MgO facets (e.g., (1 1 0) and (2 0 0)) to induce stronger unbalanced electron distribution in Mg-SLBC. Thereby, Mg-SLBC, with high adsorption capacity and adaptability, could effectively adsorb phosphate in a complex water matrix.

Ferrate(VI) Activation with Nanoconfined Cu–Mg Sites for Water Treatment: Selective Cu(III) Production via Support-Dependent Redox Catalysis

“…The performance tests in the real water matrices having different chemical compositions showed that the extent of kinetic retardation in 2,4-DBP degradation varied depending on water source (Figure c). Regardless of water matrix, Cu–Mg–C 3 N 4 /Fe­(VI) outperformed Cu–Mg–SiO 2 /Fe­(VI) and Cu–Mg–k10/Fe­(VI) in oxidative 2,4-DBP treatment and underwent marginal activity loss in Pearl River water and tap water (water quality parameters available in our previous study).…”

Phosphate Adsorption on Cerium/Terephthalic Acid Metal–Organic Frameworks (Ce‐MOF) Driven by Effective Electrostatic Attraction and Ligand Exchange in a Wide pH Range

“…The pseudo‐first‐order and pseudo‐second‐order kinetic models were conducted to analyze the adsorption kinetic data (Figure S2). The higher correlation coefficient R 2 (R 2 >0.99) of the pseudo‐second‐order model (Table S1) illustrated the dominant function of chemisorption in the phosphate adsorption process [18] . Furthermore, to better verify the adsorption kinetics form of phosphate adsorption by 1.5Ce‐MOF, the Elovich model (Figure S3) and intraparticle diffusion model (Figure S4) were used to fit the experimental data.…”

“…The higher correlation coefficient R 2 (R 2 > 0.99) of the pseudo-second-order model (Table S1) illustrated the dominant function of chemisorption in the phosphate adsorption process. [18] Furthermore, to better verify the adsorption kinetics form of phosphate adsorption by 1.5Ce-MOF, the Elovich model (Figure S3) and intraparticle diffusion model (Figure S4) were used to fit the experimental data. The preferable fitting correlations of the two models (Table S2 and Table S3) also indicated the presence of chemisorption.…”