A graphene oxide based composite granule for methylene blue separation from aqueous solution: Adsorption, kinetics and thermodynamic studies.

Graphene oxide and chitosan composite material using as a high-efficiency and low-cost granular adsorbent for methylene blue removal was fabricated via self-assembling method. The effects of pH value, contact time, initial concentration, adsorbent dose, temperature, and recyclic stability on the adsorption performance of methylene blue in aqueous solution were investigated in detail. Desorption process with the effects of solvents, contact time, and temperature were also conducted carefully in this study. The adsorption kinetics and adsorption isotherm of dye adsorption process showed that dye adsorption process was fitted to the pseudo-second-order kinetic model and the Freundlich adsorption isotherm, indicating a physical adsorption process with multilayer adsorption. The intra-particle diffusion model indicated that the dye adsorption by the granular adsorbent was strongly happened during the first 4 h. The thermodynamic study showed that the adsorption was a spontaneous and exothermic process and dye ions were condensed onto the surface of adsorbent. The maximum adsorption capacity of dye on the granular adsorbent was calculated as 951.35 mg/g and the adsorbent could maintain its adsorption performance after six cycles. In general, this study provided an efficient, cost-effective, and recyclable the granular adsorbent for dye separation from aqueous solution.

Onto the differences in formulating micro-/nanoparticulate drug delivery system from Thai silk and Vietnamese silk: A critical comparison.

Silk fibroin is a natural polymer with physicochemical properties heavily dependent on its silkworm sources and cultivation conditions. Hence, this study critically compared the characteristics and capacity to generate micro-/nanoparticles of fibroin extracted from the Thai silk and Vietnamese silk. Both Thai fibroin (SFT) and Vietnamese fibroin (SFV) were extracted and fabricated into micro-/nanoparticles using the same methods of desalination and condensation, respectively. Firstly, the amino acid compositions of SFT and SFV were determined and found to be similar, suggesting that the different cultivation conditions did not alter the fibroin chemical contents. Secondly, utilizing various analytical techniques, the SFT structure revealed less heavy chains, more light chains and P-25 glycoproteins, and lower crystallinity than those of SFV. Accordingly, compared to the particles formed by SFT, the SFV-based particles were significantly bigger (∼1700 nm vs. ∼150 nm), and possessed less drug (Amphotericin B) entrapment efficiency (64.3 ± 4.4% vs. 79.3 ± 5.1%), higher hemototoxicity, and less biostability in the blood. Conclusively, these differences add more insights for the appropriate applications of each fibroin kind to best promote its qualities and effectiveness.