Green synthesis of ultrapure La(OH)₃ nanoparticles by one-step method through spark ablation and electrospinning and its application to phosphate removal

Abstract

La(OH)₃ metal engineered nanoparticles (MENPs) are efficient phosphate binders; however, complex synthesis procedures and purity as well as agglomeration issues impede their development and practical applications. Herein, a green and a one-step method in combination with the spark ablation aerosol technology and electrospinning is proposed for the synthesis of La(OH)₃ MENPs; further, their application as phosphate binders are elucidated as a proof the concept. Material characterization results confirm the successful synthesis of ultrapure La(OH)₃ MENPs, which has not been achieved before via an environmentally friendly one-step procedure. Small angle X-ray scattering and X-ray photoelectron spectroscopy etching results show that La(OH)₃ MENPs loading on the electrospun nanofibers are uniform in both two and three dimensions. The comparative tests revealed a high phosphate adsorption capacity (110.8 mg P/g La) and indicted that the La(OH)₃ MENPs perform well; this was observed even under the interference of coexisting ions (Cl⁻, SO₄ ²⁻, NO₃ ⁻, and F⁻) at different pH values. After three cycles of solution-shaking treatment, the release of La(OH)₃ was less than 1 wt% (0.5 wt%), which was acceptable for an adsorbent. These results indicate that the La(OH)₃ MENP-loaded nanofibers are practical phosphate binders due to the simple production methods, low manufacturing cost, and impressive capacity. The proposed method significantly shortens the loading process and is a promising alternative for not only the synthesis of the adsorbent, but also for other engineering materials where loading is needed.