A series of hybrid hydrogels of poly(ethylene glycol) (PEG) were synthesized using gelatin as a crosslinker and investigated for controlled delivery of the first-generation cephalosporin antibiotic, Cefazedone sodium (CFD). A commercially available 4-arm-PEG–OH was first modified to obtain four-arm-PEG–succinimidyl glutarate (4-arm-PEG–SG), which formed the gelatin–PEG composite hydrogels (S_nN_m) through crosslinking with gelatin. To regulate the drug delivery, S_nN_m hydrogels with various solid contents and crosslinking degrees were prepared. The effect of solid contents and crosslinking degrees on the thermal, mechanical, swelling, degradation, and drug release properties of the hydrogels were intensively investigated. The results revealed that increasing the crosslinking degree and solid content of S_nN_m could not only enhance the thermal stability, swelling ratio (SR), and compression resistance capacity of S_nN_m but also prolong the degradation and drug release times. The release kinetics of the S_nN_m hydrogels were found to follow the first-order model, suggesting that the transport rate of CFD within the matrix of hydrogels is proportional to the concentration of the drug where it is located. Specifically, S₁N₁-III showed 90% mass loss after 60 h of degradation and a sustained release duration of 72 h. The cytotoxicity assay using the MTT method revealed that cell viability rates of S₁N₁ were higher than 95%, indicating excellent cytocompatibility. This study offers new insights and methodologies for the development of hydrogels as biomedical composite materials.

In view of the flue gas characteristics of cement kilns in China, the development of low-temperature denitrification catalysts with excellent anti-poisoning performance has important theoretical and practical significance. In this work, a series of MnCeO_x@TiO₂ and tourmaline-containing MnCeO_x@TiO₂-T catalysts was prepared using a chemical pre-deposition method. It was found that the MnCeO_x@TiO₂-T2 catalyst (containing 2% tourmaline) exhibited the best low-temperature NH₃-selective catalytic reduction (NH₃-SCR) performance, yielding 100% NO_x conversion at 110 °C and above. When 100–300 ppm SO₂ and 10 vol.% H₂O were introduced to the reaction, the NO_x conversion of the MnCeO_x@TiO₂-T2 catalyst was still higher than 90% at 170 °C, indicating good anti-poisoning performance. The addition of appropriate amounts of tourmaline can not only preferably expose the active {001} facets of TiO₂ but also introduce the acidic SiO₂ and Al₂O₃ components and increase the content of Mn⁴⁺ and O_α on the surface of the catalyst, all of which contribute to the enhancement of reaction activity of NH₃-SCR and anti-poisoning performance. However, excess amounts of tourmaline led to the formation of dense surface of catalysts that suppressed the exposure of catalytic active sites, giving rise to the decrease in catalytic activity and anti-poisoning capability. Through an in situ DRIFTS study, it was found that the addition of appropriate amounts of tourmaline increased the number of Brønsted acid sites on the catalyst surface, which suppressed the adsorption of SO₂ and thus inhibited the deposition of NH₄HSO₄ and (NH₄)₂HSO₄ on the surface of the catalyst, thereby improving the NH₃-SCR performance and anti-poisoning ability of the catalyst.