Huang Yang, Yin Wei, Zhao Tian-Lei, Liu Meng, Yao Qi-Zhi, Zhou Gen-Tao
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
School of Environmental Engineering and Resources, University of Science and Technology of Southwest, Mianyang 621010, China.
Nanomaterials (Basel). 2023 Mar 23;13(7):1145. doi: 10.3390/nano13071145.
Organic dyes and heavy metals often coexist in industrial effluents, and their simultaneous removal is a grand challenge. Herein, a hydrochar and MgAl layered double hydroxide (HC-MgAlLDH) nanocomposite was prepared via a facile one-step hydrothermal route, and applied to remove anionic Congo red (CR), cationic Methylene blue (MB) and Pb(II) from aqueous solutions. The nanocomposite was formed by interweaving amorphous HC and crystalline MgAlLDH nanoplates and possessed more functional groups, lower zeta potential and larger specific surface area than uncomposited MgAlLDH. Batch removal experiments showed that the components HC and LDH dominated the CR and MB removals, respectively, whereas Pb(II) removal was conjointly controlled by the two components. The maximum Langmuir removal capacities of the nanocomposite to sole CR, MB, or Pb(II) were 348.78, 256.54 or 33.55 mg/g. In binary and ternary systems, the removal capacities of CR and MB only slightly decreased, while the capacity of Pb(II) increased by 41.13-88.61%. The increase was related to the coordination of Pb(II) with the sulfur-containing groups in dyes and the precipitation of PbSO. Therefore, the simultaneous removal of CR, MB and Pb(II) was involved in a synergistic effect, including electrostatic adsorption, π-π interaction, coordination and precipitation. The present work shows that the HC-MgAlLDH nanocomposite has great potential for wastewater integrative treatment.
有机染料和重金属常常共存于工业废水中，同时去除它们是一项巨大的挑战。在此，通过简便的一步水热法制备了一种水炭与镁铝层状双氢氧化物（HC-MgAlLDH）纳米复合材料，并将其应用于从水溶液中去除阴离子型刚果红（CR）、阳离子型亚甲基蓝（MB）和Pb(II)。该纳米复合材料由无定形的HC和结晶性的MgAlLDH纳米片交织而成，与未复合的MgAlLDH相比，具有更多的官能团、更低的zeta电位和更大的比表面积。批次去除实验表明，HC和LDH组分分别主导了CR和MB的去除，而Pb(II)的去除则由这两种组分共同控制。该纳米复合材料对单独的CR、MB或Pb(II)的最大朗缪尔去除容量分别为348.78、256.54或33.55 mg/g。在二元和三元体系中，CR和MB的去除容量仅略有下降，而Pb(II)的容量增加了41.13 - 88.61%。这种增加与Pb(II)与染料中含硫基团的配位作用以及PbSO的沉淀有关。因此，CR、MB和Pb(II)的同时去除涉及到协同效应，包括静电吸附、π-π相互作用、配位作用和沉淀作用。目前的工作表明，HC-MgAlLDH纳米复合材料在废水综合处理方面具有巨大潜力。
