RWTH Aachen University, Institute for Environmental Engineering, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany.
University of Hohenheim, Institute of Agricultural Engineering, Chair of Conversion Technology and Life Cycle Assessment of Renewable Resources, Garbenstr. 9, 70599 Stuttgart, Germany.
J Environ Manage. 2018 Apr 1;211:278-286. doi: 10.1016/j.jenvman.2018.01.065. Epub 2018 Feb 4.
Activated Carbon (AC) can be used to reduce organic micropollutants (OMPs) in wastewater treatment plants (WWTPs). While producing ACs conventionally still damages the environment, this can be reduced by using renewable raw material from waste streams und producing AC locally. In this study, fibers (toilet paper) were separated out of wastewater by screening WWTP influents in full scale and then used as a no-cost, carbon-rich and heavy metal-poor raw material to produce ACs. Pretreatment was hydrothermal carbonization (HTC). Thereafter, they were activated using KOH to generate activated carbons (HTC-ACs). Their functional groups were characterized using FT-IR, and the alteration of their chemical composition was traced by elementary analysis. Adsorption tests were performed with nitrogen (BET surface) and methylene blue as standard tests. The adsorption capacity was tested with WWTP effluent and the removal of UVA as a surrogate for OMP removal was measured. After HTC and activation 13-16% of the fibers dry mass was obtained as HTC-ACs. Higher dehydration and formation of aromatic structures on the HTC-ACs were detected with FT-IR as HTC and activation temperature increased. BET surface and methylene blue adsorption of some HTC-ACs was higher than the Reference AC. Nevertheless, their ability to reduce OMPs is still lower than the Reference AC due to the different nature of their functional groups and their microporous structure that is not fully accessible for OMPs in real wastewater. Further research has to be carried out to adjust the production process so as to obtain mesoporous HTC-ACs tailored to reduce OMP concentrations and to close the carbon loop within WWTPs.
活性炭 (AC) 可用于减少废水处理厂 (WWTP) 中的有机微量污染物 (OMP)。虽然传统的 AC 生产仍然会对环境造成破坏，但通过使用废物流中的可再生原料并在当地生产 AC，可以减少这种破坏。在这项研究中，纤维（卫生纸）通过在全规模 WWTP 进水口进行筛选而从废水中分离出来，然后用作无成本、富碳和贫重金属的原料来生产 AC。预处理是水热碳化 (HTC)。此后，它们使用 KOH 进行活化以生成活性炭 (HTC-AC)。使用傅里叶变换红外光谱 (FT-IR) 对其官能团进行了表征，并通过元素分析追踪了其化学成分的变化。使用氮气 (BET 表面) 和亚甲蓝进行了吸附测试，作为标准测试。使用 WWTP 出水进行了吸附容量测试，并测量了 UVA 的去除率作为 OMP 去除率的替代指标。经过 HTC 和活化后，纤维干质量的 13-16%被转化为 HTC-AC。随着 HTC 和活化温度的升高，FT-IR 检测到 HTC-AC 上更高的脱水和芳构化结构的形成。一些 HTC-AC 的 BET 表面和亚甲蓝吸附高于参考 AC。然而，由于它们的官能团的性质不同以及它们的微孔结构在实际废水中对 OMP 不完全可及，它们减少 OMP 的能力仍然低于参考 AC。需要进一步研究以调整生产工艺，以便获得针对降低 OMP 浓度的介孔 HTC-AC，并在 WWTP 中闭合碳循环。
