Experimental design of La(OH)₃-zeolite modified wood ceramics for adsorption of total phosphorus in water and its composite properties study

Excessive total phosphorus in water triggers eutrophication, posing risks to aquatic ecosystems and human health. Modified wood ceramics were prepared by calcination: pine wood loaded with zeolite and lanthanum hydroxide modifiers was calcined in a nitrogen atmosphere. Orthogonal experimental design and multi-objective optimization methods were employed to determine optimal preparation conditions. The material's structure and properties were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) analyses. Kinetic studies were conducted to evaluate the fitting effect of different models on total phosphorus adsorption. The results showed that the pseudo-second-order model (R²=0.9996) exhibited superior fitting performance, outperforming the pseudo-first-order model and intra-particle diffusion model. Isothermal adsorption analysis was performed to characterize the adsorption process. It was found that the Freundlich model (R²=0.9903) described the process more effectively than the Langmuir model. The optimized modified wood ceramics showed exceptional performance: its total phosphorus adsorption capacity (Q) reached 24.05 ± 0.27 mg/g, and its apparent porosity (P) was 74.89 ± 1.62 %. These properties confirm its potential as an efficient and eco-friendly adsorbent for controlling eutrophication in water bodies. • La(OH)₃-zeolite dual-modified wood ceramic achieves 24.05 ± 0.27 mg/g P adsorption and 74.89 ± 1.62 % porosity. • 9-factor 3-level orthogonal design fused with multi-objective optimization achieves Q-P synergy; validated results match predictions. • Pseudo-second-order kinetics confirms chemisorption, while XRD/FT-IR evidences support the formation of LaPO₄. • The Freundlich isothermal model has the best fit, indicating heterogeneous multi-layer phosphorus adsorption. • 5 cycles show 79.1 % capacity retention with 0.3 mol/L NaOH; La leaching < 0.005 mg/L; raw material is renewable pine.