State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Sci Total Environ. 2022 Jun 25;827:154252. doi: 10.1016/j.scitotenv.2022.154252. Epub 2022 Mar 2.
On the basis of the carbonaceous skeleton assisted thermal hydrolysis that we proposed to achieve efficient sludge dewatering, this work further explored phosphorus (P) transformation in the process. The results showed that during independent thermal hydrolysis in the temperature range of 120-240 °C, organic-P was first decomposed into soluble-P and particulate-P in liquid, and then combined with Ca, Fe, and Al to form more apatite-P (AP) and less non-apatite inorganic-P (NAIP). When the skeleton assisted the sludge thermal hydrolysis, the turning point of the hydrolysis temperature would reduce from 180 °C to 150 °C, at which the liquid-P began to decrease and the organic-P generally decomposed. Moreover, the increment in the content of AP halved while that of NAIP doubled compared to that in the process without the carbonaceous skeleton. These effects come from the exogenous components introduced by adding the skeleton, which were different from the sludge. Compared with the P-rich compound and metal elements that tend to bond with phosphate introduced by the skeleton, hemicellulose as a main organic component played a leading role in the different P transformations of AP and NAIP. The hemicellulose slightly increased the acidity of sludge products, thereby inhibiting AP production and promoting the production of recyclable NAIP. Overall, the carbonaceous skeleton assisted thermal hydrolysis was beneficial for P recovery with a very low filtrate loss rate.
基于我们提出的利用碳质骨架辅助热解来实现高效污泥脱水的方法，本工作进一步探讨了该过程中的磷转化。结果表明，在 120-240°C 的独立热解温度范围内，有机磷首先分解为液体中的可溶性磷和颗粒性磷，然后与 Ca、Fe 和 Al 结合形成更多的磷灰石磷（AP）和较少的非磷灰石无机磷（NAIP）。当骨架辅助污泥热解时，水解温度的转折点将从 180°C 降低到 150°C，此时液体磷开始减少，有机磷通常分解。此外，与无碳质骨架的过程相比，AP 的含量增加了一半，而 NAIP 的含量增加了一倍。这些效果来自于添加骨架引入的外来成分，它们与污泥不同。与骨架引入的、倾向于与磷酸盐结合的富磷化合物和金属元素相比，半纤维素作为主要有机成分在 AP 和 NAIP 的不同磷转化中起主导作用。半纤维素略微增加了污泥产物的酸度，从而抑制了 AP 的生成，促进了可回收 NAIP 的生成。总的来说，碳质骨架辅助热解有利于磷的回收，滤液损失率非常低。
