ABSTRACT:

Natural adsorbent was optimized from four natural adsorption materials (kaolin, bentonite, diatomite, and natural zeolite) through the comparison of their ability to recover organic matter from an ultra-short-sludge-retention-time (ultra-short-SRT) activated sludge process effluent. Natural zeolite was modified by the loading of three types of chemical coagulants (Fe₂(SO₄)₃, Al₂(SO₄)₃, and ZnSO₄) and was used for the study of the advanced recovery of organic matter. The results of Brunauer–Emmett–Teller surface area (SBET) measurements, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses showed that natural zeolite was successfully modified, with decrease in the specific surface area of the modified zeolite (MZ), but some metal ions/metal oxides were loaded onto the surface of natural zeolite. Compared with chemical coagulant and natural zeolite, the organic recovery efficiency from the effluent of the MZs improved, and after the optimization process, the organic recovery efficiency of MZ4 (Zeolite:Fe₂(SO₄)₃ = 4:1), MZ9 (Zeolite:Al₂(SO₄)₃ = 4:1), and MZ13 (Zeolite:ZnSO₄ = 2:1) reached 72.0%, 67.6%, and 61.2%, respectively. The MZs can allow a significant amount of recovery of soluble chemical oxygen demand (SCOD) from the effluent, with SCOD recovery efficiencies for MZ4, MZ9, and MZ13 of 44.8%, 44.3%, and 39.4%, respectively. The E4/E6, UV253/UV203, and SUVA analyses after the organic recovery experiments indicated that the generation potential of disinfecting byproducts or halogenated products was reduced in the treated effluent by the MZs. The mechanism can be considered in two ways: the coagulation effect of the loaded metal ions/metal oxides and the physical and chemical adsorption effect based on the hydrogen bond and ππ bond between the MZ and organic matter. This study facilitated the application of organic recovery from wastewater and the advanced treatment of effluent.

KEYWORDS: Modified zeolite, Organic recovery, Ultra-short SRT, Effluent

摘要: 通过对四种天然吸附材料(高岭土、膨润土、硅藻土和天然沸石)在超短污泥龄活性污泥工艺出水中回收有机物的能力的比较，优选出天然吸附剂。选用三种混凝剂(Fe₂(SO₄)₃、Al₂(SO₄)₃和ZnSO₄)对天然沸石进行改性，研究了有机物质的高级回收。Brunauer-Emmett-Teller(SBET)测量表面积的结果、扫描电子显微镜(SEM)和X射线衍射(XRD)分析表明,天然沸石已成功改性,比表面积下降(MZ),但一些金属离子/金属氧化物被加载到沸石的表面。与化学混凝剂和天然沸石相比，MZs污水的有机回收效率有所提高，经过优化处理后，MZ4（沸石：Fe₂(SO₄)₃ = 4：1），MZ9（沸石：Al₂（SO₄）₃＝4∶1）和MZ13（沸石：ZnSO₄＝2∶1）分别达到72.0％，67.6％和61.2％。 MZ可以从污水中大量回收可溶性COD（SCOD），MZ4，MZ9和MZ13的SCOD回收效率分别为44.8％，44.3％和39.4％。有机物回收实验后的E4/E6，UV253/UV203和SUVA分析表明，通过MZ处理的污水中消毒副产物或卤化产物的产生潜力降低了。可以通过两种方式来考虑该机理：负载的金属离子/金属氧化物的凝聚作用以及基于MZ和有机物之间的氢键和π-π键的物理和化学吸附作用。这项研究促进了污水中有机物回收的应用和废水的深度处理。

关键词: 改性沸石, 有机物回收, 超短SRT, 污水

原载于Science of The Total Environment（2020 Impact Factor = 6.551）

原文链接：https://www.sciencedirect.com/science/article/pii/S0048969718342347