This work presented experimental and modeling studies on the simultaneous absorption of H2S and CO2 into the N-methyldiethanolamine (MDEA) and piperazine (PZ) solution in a rotating packed bed (RPB). The effect of different operating conditions, including MDEA concentration (C MDEA), PZ concentration (C PZ), liquid volumetric flow rate (L), temperature (T), and high gravity factor (β) on the absorption efficiencies of H2S and CO2 (ηH2S and ηCO2 ) were investigated. The results showed that ηH2S and ηCO2 were significantly affected by C MDEA, C PZ, L, and β. ηH2S and ηCO2 could reach 99.98 and 96.51%, respectively. Furthermore, an artificial neural network (ANN) model was established to predict ηH2S, ηCO2 , and mass-transfer coefficient (K G a). Results showed that the predicted values were in good agreement with the experimental values (within deviations of ±10% for H2S and CO2). This work provides a potential technology of simultaneous absorption of H2S and CO2 for the biogas upgrade.

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Chemical recycling of polyethylene terephthalate (PET) attracts increasing attention worldwide since it is a sustainable way to tackle the escalating plastic waste problem and create a circular plastic economy. Herein, defect-rich CeO 2 nanoparticles (NPs) with tunable sizes and shapes were conveniently synthesized by one-step precipitation with KH550 modification and first used as novel catalysts for the glycolysis of PET. Among the obtained CeO 2 catalysts, CeO 2 −2.7 nm NPs possessed the best performance for depolymerization at 196 °C, completing the reaction in 15 min with a PET conversion of 98.6% and a monomer yield of 90.3%. The glycolysis mechanism study reveals the relationship between defect engineering and catalytic activity. An ultrasmall size of 2.7 nm minimizes oxygen defect formation energy of CeO 2 NPs and increases the dispersity in ethylene glycol (EG). Rich oxygen defects on CeO 2 nanoparticles accelerate the glycolysis reaction evidently via inducing the generation of Ce 3+ and providing sites for the adsorption and activation. This work provides the application prospect of defective heterogeneous catalysts in the depolymerization reaction under low energy consumption.

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