Livestock wastewater effluent generated after the anaerobic treatment process contains the considerable amount of color-causing organic matter. In this study, a quantitative comparison of three carbon-based adsorbents included granular activated carbon (GAC), expanded graphite (EG), and multi-walled carbon nanotubes (MWNTs) was carried out for the potential application to the removal of color substances, and their mechanism was proposed. Although GAC showed the highest specific dissolved organic carbon (DOC) adsorption capacity, the color removal efficiency was the smallest among three adsorbents. The selective color removal ratios of EG and MWNTs reached 22.7 ± 0.1 PtCo/mg-DOC-removed and 21.2 ± 0.1 PtCo/mg-DOC-removed, respectively, while that of GAC was only 12.3 ± 0.1 PtCo/mg-DOC-removed. The selective adsorption of color substances by graphene-based carbon materials was due to the aromatic π–π interaction between organic matter and the hexagonal carbon lattice of graphene. The analysis of molecular weight distribution also confirmed that the exposed surface area and macro-pores were responsible for the adsorption of high molecular weight color substances. The chemical regeneration of three adsorbents was examined using 1% NaOCl solution and MWNTs showed almost complete recovery of the initial color removal capacity. In conclusion, MWNTs were the most suitable carbon nanomaterial for the selective color removal from livestock wastewater effluent.

厌氧处理过程后产生的畜禽废水中含有大量引起颜色的有机物。在这项研究中，对三种碳基吸附剂进行了定量比较，包括颗粒状活性炭（GAC），膨胀石墨（EG）和多壁碳纳米管（MWNTs），以潜在地去除有色物质，并提出了它们的机制。尽管GAC表现出最高的特定溶解有机碳（DOC）吸附容量，但脱色效率是三种吸附剂中最小的。EG和MWNT的选择性色去除率分别达到22.7±0.1 PtCo / mg-DOC去除率和21.2±0.1 PtCo / mg-DOC去除率，而GAC的选择性色去除率仅为12.3±0.1 PtCo / mg-DOC去除率。 。有机物和石墨烯的六角形碳晶格之间的π – π相互作用。分子量分布的分析还证实，暴露的表面积和大孔是高分子量有色物质的吸附原因。使用1％NaOCl溶液检查了三种吸附剂的化学再生，MWNTs几乎完全恢复了初始脱色能力。总之，MWNTs是最合适的碳纳米材料，可以选择性地去除畜禽废水中的颜色。