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In this work, a novel sustained released system (VCSB-Zn(II)) for zinc supplements was built by vanillin-chitosan Schiff base (VCSB) chelated with Zn 2+ to improve the zinc trace element utilization ratio. Samples were characterized by FT-IR, 1 H NMR, XRD, SEM, and TGA. The results showed that VCSB exhibited a more excellent chelation capacity of Zn 2+ than chitosan. The chelation capacity of VCSB was about 1.7 times more than that of chitosan, corresponding to 50.96 mg/g and 29.91 mg/g, respectively. Furthermore, VCSB-Zn(II) showed excellent sustained released performance at simulated gastric fluid because of the acid slow-dissolving ability. And the higher the CN content of VCSB, the higher the cumulative release rate (R i ) of Zn 2+ , the highest R i reached 77.81%. The sustained released curves were described by the first-order and Korsmeyer-Peppas equation, which described the Zn 2+ sustained released performance caused by the dissolution of VCSB-Zn(II) and Fick diffusion. This Zn 2+ sustained released system shows great potential in the application in the field of trace elements supplements for animals., (Copyright © 2021 Elsevier B.V. All rights reserved.)

[Display omitted] • Salicylaldehyde-chitosan Schiff base behaved an electrostatic adsorption on anionic dyes. • Salicylaldehyde-chitosan Schiff base had a greater adsorption capacity than chitosan. • Electron-donating-effect exhibited a greater impact than the -C = N content on the surface charges. • The adsorption was more affected by the -C = N hydrolysis than –NH 2. In this paper, an electropositive adsorbent, salicylaldehyde-chitosan Schiff base (SCSB), was prepared via chitosan modification. The results showed that SCSB exhibited electrostatic adsorption on anionic dyes with a better adsorption performance than chitosan, corresponding to 24.75% and 79.80% removal rate of methyl orange (MO), respectively. Furthermore, the positive charge from the C = N was not strong enough to counter the electron-donating effect of salicylaldehyde, the MO removal rates of 0.5SCSB, 1.0SCSB, and 1.5SCSB were 79.80%, 69.02% and 59.60%, respectively. In the pH test, the imine group (C = N) hydrolysis showed a greater impact on charges changing than the amino group (–NH 2) hydrolysis. [ABSTRACT FROM AUTHOR]