College of Chemistry and Molecular Engineering, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, PR China.
College of Chemistry and Molecular Engineering, East China Normal University, No. 500 Dongchuan Road, Shanghai 200241, PR China; Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, Shanghai 200062, PR China.
Sci Total Environ. 2022 Jan 15;804:150094. doi: 10.1016/j.scitotenv.2021.150094. Epub 2021 Sep 4.
Sewage sludge (SS) and polyvinyl chloride (PVC) are typical solid wastes. Their co-hydrothermal carbonization behavior was investigated in this study. The low-nitrogen solid fuel (0.94 wt%) with high heating value (9.84 MJ·Kg) was prepared through parameter optimization at 240 °C for 1.5 h under water loading amount of 0.84 g·cm. In an acidic environment, the stubborn protein in SS could be converted into free amino acids, which were generated by the decomposition of PVC under hydrothermal conditions. The stubborn N could be translated into easy-to-remove N, such as nitrile-N and inorganic N, and the dehydration reaction was evidently promoted. The acidic environment at high temperatures caused the dissolution of ash in SS and improved the combustion performance of hydrochar. FT-IR results showed that, with increased PVC loading proportion, -C=N- was converted into -C=O-. Co-hydrothermal carbonization could effectively improve the combustion performance of hydrochar. The addition of PVC could lead to the generation of increased volatile matter, fixed carbon, and unsaturated CC, and the combustion temperature range shifted to a high range. However, the generation of graphite-like carbon was caused by further increasing the PVC loading proportion, which hindered the improvement of its combustion performance. In the parameter optimization study, the increased water loading amount (from 0.54 g·cm to 0.84 g·cm) had the most evident effect on the N content in the hydrochar (from 1.50 wt% to 0.94 wt%), which promoted the denitrification efficiency (from 60.11% to 75.00%) and the conversion of -C=N- components, and prevented further polymerization of solid products.
污水污泥 (SS) 和聚氯乙烯 (PVC) 是典型的固体废物。本研究考察了它们的共水热碳化行为。通过参数优化，在 240°C 下水载量为 0.84g·cm 下反应 1.5h，制备出含氮量低（0.94wt%）、高热值（9.84MJ·Kg）的固体燃料。在酸性环境下，SS 中的顽固蛋白可以转化为游离氨基酸，这些氨基酸是 PVC 在水热条件下分解生成的。顽固氮可以转化为易去除的氮，如腈基氮和无机氮，并且脱水反应明显得到促进。高温下的酸性环境导致 SS 中灰分的溶解，提高了水热炭的燃烧性能。FT-IR 结果表明，随着 PVC 负载比例的增加，-C=N-转化为-C=O-。共水热碳化可以有效提高水热炭的燃烧性能。添加 PVC 会导致挥发性物质、固定碳和不饱和 CC 的增加，燃烧温度范围向高温转移。然而，进一步增加 PVC 的负载比例会导致石墨状碳的生成，从而阻碍其燃烧性能的提高。在参数优化研究中，增加水载量（从 0.54g·cm 增加到 0.84g·cm）对水热炭中的氮含量（从 1.50wt%降低到 0.94wt%）影响最明显，这促进了脱氮效率（从 60.11%提高到 75.00%）和-C=N-组分的转化，防止了固体产物的进一步聚合。
