School of Environment Studies, China University of Geosciences, Wuhan, 430074, Hubei, China.
Faculty Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, Hubei, China.
Chemosphere. 2020 Mar;243:125333. doi: 10.1016/j.chemosphere.2019.125333. Epub 2019 Nov 9.
Pyrolysis carbonisation is a promising technology to convert organic waste into valuable carbon-based materials. However, sludge is generally highly compressible and difficult to dewater because of its high concentrations of biopolymers; the bound water of sludge is trapped in a network composed of biopolymers. Therefore, chemical conditioning is an indispensable step for improving sludge dewaterability performance. In the present work, the effects of different chemical conditioning agents (polymeric aluminium chloride (PACl), iron(III) chloride (FeCl), KMnO-Fe(II) and Fenton's reagent) on the physicochemical properties of sludge-based carbons (SBCs) were systematically studied and the SBCs were further used in advanced wastewater treatment. The adsorption mechanisms of dissolved organic matters (DOMs) by different SBCs were also investigated. The results showed that conditioning with KMnO-Fe(II) and Fenton's reagent improved the specific surface area of the SBCs, whereas inorganic salt flocculation conditioning reduced the porosity of the SBCs. In addition, we found that the Fenton-SBC and Mn/Fe-SBC performed better than the other investigated SBCs in the removal of organic compounds from secondary effluent and that the pseudo-second-order kinetic model could better describe the process of DOMs adsorption by all of the investigated SBCs. Moreover, three-dimensional fluorescence excitation-emission matrix spectroscopy in combination with an analysis of the physical and chemical fractionation of DOMs showed that all of the SBCs performed well in the adsorption of aromatic substances, hydrophobic acids and hydrophobic neutrals, whereas the Mn/Fe-SBC and Fenton-SBC performed better than the other SBCs in the removal of weakly hydrophobic acids.
热解碳化是将有机废物转化为有价值的碳基材料的一种很有前途的技术。然而，由于污泥中含有大量的生物聚合物，因此其具有很高的可压缩性和脱水难度；污泥中的结合水被困在由生物聚合物组成的网络中。因此，化学调理是改善污泥脱水性能不可或缺的步骤。在本工作中，系统研究了不同化学调理剂（聚合氯化铝（PACl）、三氯化铁（FeCl）、KMnO4-Fe(II) 和芬顿试剂）对基于污泥的碳（SBC）的物理化学性质的影响，并进一步将 SBC 用于高级废水处理。还研究了不同 SBC 对溶解有机物（DOMs）的吸附机制。结果表明，KMnO4-Fe(II) 和芬顿试剂调理可提高 SBC 的比表面积，而无机盐絮凝调理则降低了 SBC 的孔隙率。此外，我们发现 Fenton-SBC 和 Mn/Fe-SBC 在去除二级出水中的有机化合物方面优于其他研究的 SBC，并且伪二阶动力学模型可以更好地描述 DOMs 吸附过程。此外，三维荧光激发-发射矩阵光谱结合 DOMs 的物理和化学分级分析表明，所有 SBC 均能很好地吸附芳香物质、疏水性酸和疏水性中性物质，而 Mn/Fe-SBC 和 Fenton-SBC 在去除弱疏水性酸方面的性能优于其他 SBC。
