Zhou Juanjuan, Yang Ying, Li Zhanjun
School of Health, Guangzhou Vocational University of Science and Technology, Guangzhou, 510080, People's Republic of China.
School of Environment, Jinan University, Guangzhou, 511436, People's Republic of China.
Sci Rep. 2024 Sep 11;14(1):21232. doi: 10.1038/s41598-024-72258-6.
MgO nanoparticles have good As-adsorption capacity in treating As-contaminated wastewater but suffer from high production cost. In this study, instead of using pre-formed MgO nanoparticles, we found that in-situ formed Mg(OH) from MgCl and NaOH reaction exhibited super high arsenate (As(V)) removal efficiency. Only 1.5 mmol/L of in-situ formed Mg(OH) could remove more than 95% As(V) within 10 min to make the As contaminated water (10 mg-As(V)/L) meet the municipal wastewater treatment standard, whereas MgO nanoparticles failed. The Mg-As sludge has an amorphous crystal structure while no Mg(OH) phase could be observed. As(V) existed uniformly within the sludge which was confirmed by elemental mapping. A precipitation-adsorption-coagulation mechanism might exist, which could relieve the restriction of limited surface area of solid MgO adsorbents. This study not only reveals an applicable method for efficient removal of trace level As(V) from water but also implies the huge potential of in-situ formed adsorbents in water treatment.
氧化镁纳米颗粒在处理含砷废水方面具有良好的砷吸附能力，但生产成本较高。在本研究中，我们没有使用预先形成的氧化镁纳米颗粒，而是发现由氯化镁和氢氧化钠反应原位形成的氢氧化镁表现出超高的砷酸盐（As(V)）去除效率。仅1.5 mmol/L的原位形成的氢氧化镁就能在10分钟内去除超过95%的As(V)，使含砷废水（10 mg-As(V)/L）达到城市污水处理标准，而氧化镁纳米颗粒则无法做到。镁-砷污泥具有无定形晶体结构，未观察到氢氧化镁相。通过元素映射证实，As(V)均匀存在于污泥中。可能存在沉淀-吸附-凝聚机制，这可以缓解固体氧化镁吸附剂有限表面积的限制。本研究不仅揭示了一种从水中高效去除痕量As(V)的适用方法，还暗示了原位形成的吸附剂在水处理中的巨大潜力。
