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It is a challenge to achieve the harmless treatment and resourceful use of various metal elements in electroplating sludge, and converting them into functional materials has become an important technological direction. Based on the existence of various metal ions in electroplating sludge, sodium oleate intercalated Zn−Cr‐LDHs (Zn−Cr‐layered double hydroxides) were prepared by two‐phase solution heating method. The adsorption process of the prepared LDHs for Congo red (CR) in aqueous solution can be described by Langmuir isotherm model and pseudo‐second‐order kinetic model and the maximum adsorption capacity is 2750.43 mg/g. The results of TEM and XPS show that the adsorption mechanism is dominated by electrostatic adsorption, ion exchange process, hydrogen bonding interaction and surface complexation. Therefore, this paper provides a strategy for recovering metal elements from electroplating sludge to prepare LDHs adsorption materials with ultra‐high adsorption capacity. [ABSTRACT FROM AUTHOR]

In this paper, fly ash (FA) was successfully prepared into graphene‐like carbon composite materials (GCC) with good adsorption properties for heavy metals by alkali activation‐Hummer oxidation method. What's more, the sulfate in the waste liquid can be collected by concentration, and sulfuric acid can be recycled several times after treatment. FA has been fully recycled in an inexpensive and environmentally friendly way. Compared with FA, the specific surface area of GCC increased about 50 times, and the pore size decreased from 9.49 nm to 4.5 nm. The adsorbing amount of GCC could attain 79.38 mg g−1 within 90 min at pH=6. The experimental data of lead adsorption by GCC showed that the results were very consistent with the Freundlich adsorption model. The adsorbent prepared in this work has a good application prospect in water pollution control, which provides a new approach for resource recovery of FA. [ABSTRACT FROM AUTHOR]

The development of high performance magnetic nanomaterials has a good application prospect in wastewater treatment. Herein, Fe3O4/C nanocomposites was synthesized by eco‐friendly hydrolysis‐calcination method using potassium fulvic acid (FA−K) and FeCl3⋅6H2O as raw materials. The morphology of Fe3O4/C nanocomposites exhibited a loose pore structure with uniform size (a diameter ∼ 27 nm). The prepared Fe3O4/C nanocomposites possessed excellent dispersibility and magnetic properties in aqueous solution. The removal efficiency and maximum adsorption capacity of Fe3O4/C nanocomposites were 98% and 64.0 mg g−1, respectively. Moreover, it was confirmed that the adsorption mechanism of Cr(VI) contains electrostatic attraction and redox reaction. In this work, we provide a convenient means for manufacturing Fe3O4/C nanocomposites, and prove that FA−K is a cheap carbon source for manufacturing Fe3O4/C nanocomposites, which makes Fe3O4/C nanocomposites have potential application value in the effective adsorption of Cr(VI). [ABSTRACT FROM AUTHOR]