One-pot fabrication of sacchachitin for production of TEMPO-oxidized sacchachitin nanofibers (TOSCNFs) utilized as scaffolds to enhance bone regeneration.

One-pot fabrication of sacchachitin (SC) for mass-production was developed and optimized by selecting KOH as alkaline agent in depigmentation step and utilizing NaClO2 as bleaching agent in subsequent step in the same pot. Overall yield of one-pot-fabricated SC was up to 35 %w/w of initial weight with a fibrous texture soft enough for mechanical disintegration into SC nanofibers (SCNFs) and better dispersion for producing TEMPO-oxidized SCNFs (T033SC). Both SCNFs and T033SC could form a 3D gelatinous scaffold into which MC3T3-E1 cells were attracted. Higher calcium-trapping ability of T033SC resulting from a greater extent of carboxylate groups provided an excellent bone regeneration environment that resulted in better outcomes of bone regeneration in a femur defect rat model compared to those with SCNFs possessed fewer carboxylate groups. In conclusion, biomaterial scaffolds based on TEMPO-oxidized SCNFs produced from one-pot fabricated SC showed great potential for bone regeneration due to unique physical and chemical properties.

Simultaneous wet desulfurization and denitration by an oxidant absorbent of NaClO2/CaO2.

The simultaneous wet removal performance of NO and SO2 was studied using the oxidant absorbent NaClO2/CaO2. The factors were studied including NaClO2 and CaO2 concentrations, reaction temperature, and gaseous components, such as SO2, NO, O2, and CO2. The products in liquid and solid phases were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and ion chromatography to determine the mechanism of simultaneous desulfurization and denitration by NaClO2/CaO2. The results indicated that the removal efficiency of SO2 was in the range of 98-99.9%, and the removal efficiencies of NO and NOx were 99.4% and 95.0%, respectively. The removal efficiencies of NO and NOx increased with the increase of NaClO2 and CaO2 concentration and reaction temperature. The gaseous components had a stronger effect on NOx removal efficiency, followed by NO removal efficiency, and SO2 removal efficiency. As SO2 concentration increased, the generation of sulfite species promoted the removal of NO and NOx. Competition for NO2 and SO2 absorption by absorbent inhibited the removal efficiencies of SO2 and NOx. The presence of O2 was beneficial for removing SO2, NO, and NOx, while the presence of CO2 was not. The main products in the liquid and solid phases were NO3-, NO2-, SO42-, and CaSO4. The reaction mechanism for simultaneous wet removal of SO2 and NO by NaClO2/CaO2 is proposed and discussed.