Zhang Xiangling, Gao Jingtian, Lei Yu, Xu Zhouying, Xia Shibin, Jiang Yinghe, Cheng Jing
School of Civil Engineering and Architecture, Wuhan University of Technology 122, Luoshi Road, Hongshan District Wuhan China 430070
RSC Adv. 2019 Dec 2;9(68):39811-39823. doi: 10.1039/c9ra04826j.
This work presents novel materials, ZnFe-LDHs-modified (Zn : Fe molar ratio of 2 : 1 and 3 : 1) and ZnAl-LDHs-modified (Zn : Al molar ratio of 2 : 1 and 3 : 1) zeolites, which were synthesized under alkaline conditions a co-precipitation method and coated on original zeolites. The as-prepared LDHs-modified zeolites were used as substrates for a constructed rapid infiltration system (CRIS) to conduct purification experiments to investigate the phosphorus removal performance of all types of zeolites. The experimental results showed that the phosphorus removal rates of the Zn-LDHs-modified zeolites reached over 80%, which are superior to that of the original zeolites. Furthermore, isothermal adsorption and adsorption kinetic experiments were conducted to explore the adsorption mechanisms. The theoretical maximumadsorption capacities were efficiently enhanced owing to the Zn-LDHs coating strategy. Especially, that of the ZnFe-LDHs-modified (3 : 1) zeolites reached 434.78 mg kg, which is much higher than that of the original zeolites. Meanwhile, according to the fitting results of the adsorption kinetics experiments, it was found that the predominant adsorption type of the original zeolites was converted from intrinsically weak physical adsorption into more stable chemical adsorption by the Zn-LDHs coating. Furthermore, high-throughput sequencing was also exerted to uncover the phosphorus removal mechanism by microorganisms. The obtained results indicate that the relative abundance of and , which are closely related to phosphorus removal, effectively increased. Overall, the Zn-LDHs-modified zeolites improved the phosphorus removal performance efficiently and sustainably when applied in CRIS.
本研究制备了新型材料，即通过共沉淀法在碱性条件下合成的锌铁层状双氢氧化物改性（锌与铁摩尔比为2∶1和3∶1）和锌铝层状双氢氧化物改性（锌与铝摩尔比为2∶1和3∶1）的沸石，并将其负载于原始沸石上。将所制备的层状双氢氧化物改性沸石用作构建快速渗滤系统（CRIS）的基质，进行净化实验以研究各类沸石的除磷性能。实验结果表明，锌层状双氢氧化物改性沸石的除磷率达到80%以上，优于原始沸石。此外，还进行了等温吸附和吸附动力学实验以探究吸附机制。由于采用了锌层状双氢氧化物负载策略，理论最大吸附容量得到有效提高。特别是，锌铁层状双氢氧化物改性（3∶1）沸石的理论最大吸附容量达到434.78 mg/kg，远高于原始沸石。同时，根据吸附动力学实验的拟合结果发现，通过锌层状双氢氧化物负载，原始沸石的主要吸附类型从本质上较弱的物理吸附转变为更稳定的化学吸附。此外，还运用高通量测序技术揭示微生物的除磷机制。所得结果表明，与除磷密切相关的 和 的相对丰度有效增加。总体而言，锌层状双氢氧化物改性沸石应用于CRIS时能有效且可持续地提高除磷性能。
