Xiaofang You,Yuxia Hou,Jingwei Wang,Lin Li,Meng He
This study aims to address the challenge of treating Pb 2+ in mining wastewater, a persistent issue in water environment pollution control. The sodium alginate/graphene oxide/polyethylene glycol (SA/GO/PEG) gel beads were designed and prepared with graphene oxide (GO), sodium alginate (SA), and polyethylene glycol (PEG) as raw materials by combining experiments and simulation. Firstly, the simulation system of SA/GO/PEG gel bead was constructed through molecular simulation, and the optimal composition of SA/GO/PEG gel bead was determined. The simulation results indicated that, with a PEG polymerization degree of 4000, the SA/GO/PEG gel bead system exhibited the greatest structural stability and the most effective cross-linked. Based on the understanding of the structure–performance relationship, SA/GO/PEG4000 gel beads were prepared to achieve an adsorbent with both high adsorption capacity and good stability. Characterization results indicated the successful cross-linked of polyethylene glycol with sodium alginate and graphene oxide, which not only introduced additional oxygen-containing functional groups and increased the crystallinity of the gel beads but, more importantly, led to the formation of a dense and complex three-dimensional network. This structure contributed to the improved thermal stability of the composite. Adsorption experiments showed that the adsorption of Pb 2+ onto SA/GO/PEG gel beads followed the Langmuir isotherm model. The calculated maximum adsorption capacities at 25°C, 35°C, and 45°C were 490.20, 497.51, and 526.32 mg/g, respectively. Furthermore, the gel beads exhibited excellent reusability, retaining 92.64% of their initial adsorption capacity after four consecutive adsorption–desorption cycles.
Graphene oxide (GO) is a biocompatible nanomaterial that has an inhibitory effect on insulin amyloid fibrillation. In order to enhance the inhibitory effect of GO and explore the rules of electrostatic interactions on the inhibitory effect, carboxyl group, PEI and PEG were coupled to the GO nanoplatelet surface to prepare inhibitors of different surface electrical properties. The effects of surface electrical properties of inhibitors on insulin fibrillation were investigated. The results showed that GO, carboxyl group modified GO (GO-COOH), PEI modified GO (GO-PEI), and PEG modified GO (GO-PEG) inhibited insulin fibrillation in a dose-dependent manner. Compared with GO, positive charge-modified GO-PEI and negative charge-modified GO-COOH enhanced the inhibitory effect, while uncharged polymer-modified GO-PEG weakened the inhibitory effect. The inhibitory effect of the inhibitors increased with the increase of surface charge density. The difference in inhibitory effect between GO-PEI and GO-COOH was due to the different electrostatic interactions between inhibitors and insulin, and the different inhibition mechanisms. In addition, inhibitors mainly interact with insulin during the nucleation phase to hinder insulin fibrillation. The charge modifications of graphene oxide enhanced the inhibitory effect on insulin fibrillation based on electrostatic interactions, which will provide new thoughts for the development of anti-amyloid fibrillation drugs.
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