Combustion of fossil fuels gives rise to sulfur oxides, which are harmful to the environment. Adsorptive desulfurization (ADS) of diesel was conducted using sewage sludge activated with H₂O₂ as the oxidizing agent. A full 2² central composite response surface design was employed to determine optimum conditions for the production of activated sewage sludge (ASS). The adsorbent (ASS) was characterized using SEM, EDX and FTIR and the results of the analysis showed that it has the capacity to desulfurize diesel significantly. The ASS was subsequently used to conduct batch ADS of diesel with a view to investigate the kinetics, equilibrium and thermodynamics of the process. The optimum conditions established for the production of ASS using H₂O₂ as the oxidizing agent were: temperature 400 °C and holding time 60 min. The Elovich model gave the best fit to the kinetic data of the ADS of diesel using ASS, while the equilibrium study showed that the Freundlich isotherm fitted the data at 35 °C better than Temkin and Langmuir isotherms. The positive values of the free energy and enthalpy changes revealed that the process was non-spontaneous and endothermic, respectively, while the negative entropy change is evidence of decrease in randomness of the adsorbed species. 33% desulfurization was achieved in 100 min during ADS of diesel showing that the adsorbent developed by activating SS with H₂O₂ was very good and effective. Thus, ASS can be used to gain more insight into kinetics, equilibrium and thermodynamics of the ADS of middle-distillate petroleum fractions.

中文翻译：

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活性污泥对柴油的吸附脱硫：动力学，平衡和热力学研究

化石燃料的燃烧会产生氧化硫，这对环境有害。柴油的吸附脱硫（ADS）使用以H ₂ O ₂为氧化剂活化的污水污泥进行。使用完整的2 ²中央复合响应面设计来确定生产活性污泥（ASS）的最佳条件。用SEM，EDX和FTIR对吸附剂（ASS）进行了表征，分析结果表明该吸附剂具有明显的柴油脱硫能力。随后使用ASS进行批次的柴油ADS，以研究该过程的动力学，平衡和热力学。建立使用H ₂生产ASS的最佳条件O ₂作为氧化剂：温度为400°C，保持时间为60分钟。Elovich模型最适合使用ASS的柴油ADS动力学数据，而平衡研究表明Freundlich等温线在35°C时比Temkin和Langmuir等温线拟合得更好。自由能和焓变的正值表明该过程分别是非自发的和吸热的，而负熵变则表明吸附物种的随机性降低。柴油ADS在100分钟内实现33％的脱硫，表明吸附剂是通过用H ₂ O ₂活化SS产生的非常好和有效。因此，可以使用ASS来更深入地了解中间馏分石油馏分ADS的动力学，平衡和热力学。