Department of Environment and Energy, Sejong University, Seoul 05005, Republic of Korea.
Advanced Technology Department, Land & Housing Institute, Daejeon 34047, Republic of Korea.
Environ Int. 2019 Nov;132:105037. doi: 10.1016/j.envint.2019.105037. Epub 2019 Aug 19.
In an effort to seek a new technical platform for disposal of drinking water treatment sludge (DWTS: alum sludge), pyrolysis of DWTS was mainly investigated in this study. To establish a more sustainable thermolytic platform for DWTS, this study particularly employed CO as reactive gas medium. Thus, this study laid great emphasis on elucidating the mechanistic roles of CO during the thermolysis of DWTS. A series of the TGA tests of DWTS in CO in reference to N revealed no occurrence of the heterogeneous reaction between CO and the sample surface of DWTS. As such, at the temperature regime before initiating the Boudouard reaction (i.e., ≥700 °C), the mass decay patterns of DWTS in N and CO were nearly identical. However, the gaseous effluents from lab-scale pyrolysis of DWTS in CO in reference to N were different. In sum, the homogeneous reactions between CO and volatile matters (VMs) evolved from the thermolysis of DWTS led to the enhanced generation of CO. Also, CO suppressed dehydrogenation of VMs. Such the genuine mechanistic roles of CO in the thermolysis of DWTS subsequently led to the compositional modifications of the chemical species in pyrolytic oil. Furthermore, the biochar composite was obtained as byproduct of pyrolysis of DWTS. Considering that the high content of AlO and Fe-species in the biochar composite imparts a strong affinity for As(V), the practical use of the biochar composite as a sorptive material for arsenic (V) was evaluated at the fundamental levels. This work reported that adsorption of As(V) onto the biochar composite followed the pseudo-second order model and the Freundlich isotherm model.
为寻求处理饮用水处理污泥（DWTS：明矾污泥）的新技术平台，本研究主要研究了 DWTS 的热解。为建立更可持续的 DWTS 热解平台，本研究特别采用 CO 作为反应性气体介质。因此，本研究特别强调阐明 CO 在 DWTS 热解过程中的机械作用。在 CO 中与 N 参照的 DWTS 的一系列 TGA 测试表明，CO 与 DWTS 样品表面之间没有发生多相反应。因此，在引发 Boudouard 反应之前的温度范围内（即≥700°C），N 和 CO 中 DWTS 的质量衰减模式几乎相同。然而，来自 DWTS 在 CO 中实验室规模热解的气态流出物与 N 不同。总之，CO 与从 DWTS 热解中产生的挥发性物质（VMs）之间的均相反应导致 CO 的生成增加。此外，CO 抑制了 VMs 的脱氢作用。CO 在 DWTS 热解中的这些真正的机械作用随后导致热解油中化学物质的组成发生变化。此外，还获得了 DWTS 热解的生物炭复合材料作为副产物。考虑到生物炭复合材料中高含量的 AlO 和 Fe 物质对 As(V) 具有很强的亲和力，因此在基础水平上评估了生物炭复合材料作为砷（V）吸附材料的实际用途。本工作表明，As(V) 吸附到生物炭复合材料上遵循伪二级模型和 Freundlich 等温线模型。
