Yi Meng,Tanglong Liu,Shanshan Yu,Yi Cheng,Jie Lu,Xianzheng Yuan,Haisong Wang
A recyclable and high-efficiency nanoscale adsorbent is prepared from sustainable resources in this study. Inspired by the amino acid and phenolic hydroxyl group in reed root acting as active sites for adsorption, a chemically modified method is employed, where lignin is improved with glycine to prepare a biomimic adsorbent with a synergistic effect of amino acid and phenolic hydroxyl. By blending with nano-Fe3O4, the modified lignin is applied to synthesize lignin derivate magnetic nanogels that adsorb inorganic ions and organic dyes. The maximum capacities of the adsorption are highly improved, whereas unmodified lignin-based adsorbents reveal a low adsorption capacity under the same conditions. The used nanogels are recycled by magnetic separation and regenerated in hydrochloric acid, and the tests are repeated three times. All the regeneration ratios are over 90%, thus ensuring reusability. Finally, the as-prepared nanogels are applied to treat pulp bleaching effluents, revealing one potential application in industry. The designing concept of the recyclable nanogel in this study provides a biomimic strategy of using sustainable resources to treat contamination.
Protective corrosion coatings are preferably composed of available, environmentally friendly, and low-volatility organic compounds. Herein, new excellent corrosion graphene/raw lacquer composite coatings were formed, in which waterborne graphene was modified by taking lignin tripolymer (LT) as an aqueous stabilizer and subsequently adding to raw lacquer (RL). Graphene/lacquer composite coatings were achieved by an eco-friendly fabrication process. The structure and thermostability of the lignin derivative were studied by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry (TG), respectively, while the composition of the LT was characterized by Raman spectrometry. And the experimental result revealed that LT was an effective graphene dispersant (LTG) up to 60 d without any precipitation. Besides, the SEM of the graphene/lacquer coatings revealed that the excellent protection properties were highly attributable to the formation of a very rough surface, because of the highly dispersed nature of the graphene nanoparticles. Also, the corrosion behavior of the composite coatings on a metal substrate were studied by polarization curve analysis and electrochemical impedance spectroscopy (EIS). According to the electrochemical corrosion tests, the lacquer composite coating with 5 wt% LTG dispersion (RL/LTG-5, containing 0.3 wt% graphene) possessed excellent corrosion resistance, making it suitable for protecting bare metal substrates.
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