Lanthanum/iron co-modified biochar for highly efficient adsorption of low-concentration phosphate from aqueous solution

Given the rigorous discharge standards and the low-concentration phosphate in wastewater, there is an urgent demand for the development of economically efficient materials and technologies for removing lowconcentration phosphate. In this study, a highly efficient adsorbent for low-concentration phosphate, known as lanthanum and iron co-modified sawdust biochar(La-MBC), was successfully synthesized. The La-MBC displayed outstanding adsorption performance in the treatment of low-concentration phosphate wastewater with a phosphate removal rate of around 100% when the phosphate concentration was below 1.0 mg/L. Moreover, the results of adsorption isotherms indicated that the maximum adsorption capacity of phosphate by La-MBC was nearly 27.49 mg/g. The results demonstrated that La-MBC maintained significant stability in phosphate adsorption, achieving a removal efficiency exceeding 90% across the pH range of 4 to 8. More attractively, LaMBC has been demonstrated impressive selectivity in adsorbing phosphate, even in the presence of competing ions. Characterization findings and adsorption experiments provided evidence that the adsorption of phosphate by La-MBC was mainly driven by chemisorption. Collectively, these findings strongly indicate that La-MBC is an exceptional choice for efficiently removing low-concentration phosphate in real-world applications.