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 low-concentration 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, La-MBC 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.