Junhao Lin,Qinxiong Liao,Yaping Hu,Rui Ma,Chongwei Cui,Shichang Sun,Xiangli Liu
The generation of sulfur-containing pollution products affects the quality of biofuels obtained from the supercritical water gasification (SCWG) of sludge . This study investigates the effects of the gasification temperature, moisture content, and reaction atmosphere on the evolution of sulfur-containing compounds. The results showed that temperature was the key parameter causing the migration of sulfur from sludge to biogas and liquid products. The sludge decomposition reaction was dominated by ionic reactions at 360 °C, while the decomposition of organic matter was converted to free radical reactions as the temperature increased from 380 °C to 440 °C. The mercaptan and thioether contents of the bio-oil decreased to 0.3% at 440 °C. Correspondingly, the concentration of H 2 S increased from 6.7 ppm to 38.0 ppm. The decomposition of organic sulfur with an unstable structure (S-H bond and S-C bond) was the main cause of the increase in the content of H 2 S. Additionally, the solubility and oxidation properties of supercritical water were extremely strong. Some sulfur-containing organic compounds were converted into SO 4 2- via hydrolysis and oxidation reactions, forming sulfate crystals with heavy metals in the bio-char, which aided in achieving the synergistic immobilization of sulfur and heavy metals.
Riyi Lin,Kai Chen,Mingqiang Miao,Liqiang Zhang,Xinwei Wang,Ye Jiang,Jianliang Zhang,Yue Wang,Huida Pan
The generation of H2S causes many problems during steam injection thermal recovery. To make clear the formation rule of H2S under the condition of steam injection thermal recovery, tetrahydrothiophene was selected as a model compound, and then reaction mechanism and kinetics were explored based on indoor thermal simulation. The results showed that tetrahydrothiophene aquathermolysis reaction can generate a large amount of H2S. The C–S bond formed by heteroatom S broke at first and then opening-ring occurred, which produced small molecular alkanes or alkenes. The decarbonylation of aldehydes and other organic compounds resulted in the formation of CO, hydrocarbons, and other related compounds. High-temperature water played a key role in the process of tetrahydrothiophene aquathermolysis reaction and would directly participate in the elementary reactions such as hydrolysis and water–gas shift reaction (WGSR). These elementary reactions would finally lead to the migration of hydrogen from water to gas-phase or liquid-phase products. In addition, a kinetic model of H2S formation during tetrahydrothiophene aquathermolysis reaction was established through kinetic experiments, the activation energy is 54.55 kJ/mol, and the frequency factor is 166.47 day–1.
Due to the immunosuppressive tumor microenvironment (TME) and weak radiation absorption, the immune response triggered by radiation therapy (RT) is limited. Herein, a core–shell nanosensitizer UiO@MnS (denoted as UM) was genuinely constructed for the amplification of RT efficacy and induction of immunogenicity via integrating MnS-reprogrammed TME with Hf-based UiO-sensitized RT. The acid-sensitive MnS would produce H2S under acidic TME to improve oxygenation through inhibition mitochondrial respiration and reducing metabolic oxygen consumption, leading to decreased HIF-1α expression and enhanced radiosensitization. In addition, the generated H2S inhibited the catalase activity to increase the H2O2 level, which subsequently enhanced the Mn2+-mediated Fenton-like reaction, resulting in G2/M cell cycle arrest to improve the cellular sensitivity for radiation. This impressive tumor oxygenation, cell cycle arrest, and radiosensitization procedure boosted RT efficacy and resulted in strong antitumor immunogenicity. Taken together, combining the immunosuppressive TME modulation with a sensitizing radiation strategy shows great promise for magnifying immunogenic RT outputs.
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