Abstract Re-use of the byproduct wastes resulting from different municipal and industrial activities in the reclamation of contaminated water is real application for green projects and sustainability concepts. In this direction, the synthesis of composite sorbent from the mixing of waterworks and sewage sludge coated with new nanoparticles named “siderite” (WSSS) is the novelty of this study. These particles can be precipitated from the iron(II) nitrate using waterworks sludge as alkaline agent and source of carbonate. Characterization tests using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) mapping revealed that the coating process was correctly achieved and siderite nanoparticles were planted on the surface of the composite sorbent. Interaction between Congo Red dye and composite sorbent was evaluated through a set of batch tests under the variation of agitation time, pH of aqueous solution, and sorbent dosage. The results proved that the prepared sorbent had a high ability in the treatment of water contaminated with Congo Red dye in comparison with previous studies and the maximum adsorption capacity reached to maximum value i.e. 9416 mg/g. The sorption process was governed by electrostatic attractions; however, Sips and Pseudo-second-order models described this process with coefficient of determination greater than 0.99. Graphic abstract

中文翻译：

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菱铁矿纳米颗粒包覆新型复合吸附剂的合成及其在刚果红染料污染水体修复中的应用

摘要 不同市政和工业活动产生的副产品废物在污染水的回收利用中的再利用是绿色项目和可持续性概念的真正应用。在这个方向上，从水厂和污水污泥混合合成复合吸附剂是本研究的新颖之处，该纳米颗粒涂有名为“菱铁矿”（WSSS）的新型纳米颗粒。这些颗粒可以使用水厂污泥作为碱性试剂和碳酸盐来源从硝酸铁 (II) 中沉淀出来。使用 X 射线衍射 (XRD)、扫描电子显微镜 (SEM) 和能量色散谱 (EDS) 映射的表征测试表明，涂层过程正确实现，并且菱铁矿纳米颗粒被植入复合吸附剂的表面。在搅拌时间、水溶液的 pH 值和吸附剂剂量的变化下，通过一组批次测试评估刚果红染料和复合吸附剂之间的相互作用。结果证明，与以往的研究相比，所制备的吸附剂对刚果红染料污染水的处理能力强，最大吸附量达到最大值，即9416mg/g。吸附过程受静电吸引力控制；然而，Sips 和伪二阶模型以大于 0.99 的决定系数描述了这个过程。图形摘要 结果证明，与以往的研究相比，所制备的吸附剂对刚果红染料污染水的处理能力强，最大吸附量达到最大值，即9416mg/g。吸附过程受静电吸引力控制；然而，Sips 和伪二阶模型以大于 0.99 的决定系数描述了这个过程。图形摘要 结果证明，与以往的研究相比，所制备的吸附剂对刚果红染料污染水的处理能力强，最大吸附量达到最大值，即9416mg/g。吸附过程受静电吸引力控制；然而，Sips 和伪二阶模型以大于 0.99 的决定系数描述了这个过程。图形摘要