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ABSTACT: Effects of the cyanuric acid (CA) on the isothermal and non-isothermal crystallization, morphology, polymorphic crystalline structure and phase transition on the PBA have been investigated systematically by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy. The non-isothermal crystallization temperature increased upon addition of the CA. The crystallization kinetics in the isothermal crystallization was quantitatively analyzed. The CA is an effective nucleating agent for the enhanced nucleation density and decreased spherulite size of the PBA.Addition of the CA was favorable for the formation of the PBA α modification, and accelerated the phase transition from the β-to α-modification. The mechanisms of nucleation, preferential formation of the PBA α modification, and accelerated phase transition have also been proposed.

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Chitosan (CTS) derivative adsorbent [P-C-CTS-(Hg)] was prepared by employing the polyamination and Hg 2+imprinted technologies for Hg 2+ removal from a low-concentration aqueous solution (C Hg 2+ ≤ 40 mg•L −1 ). The prepared adsorbents were characterized by Fourier transform infrared spectroscopy, and their physical and chemical properties were compared. The adsorption capacity of P-C-CTS-(Hg) beads to Hg 2+ was 2.2 times higher than that of CTS beads because of the increased number of amide groups as adsorption sites. The adsorption processes and mechanisms at pH from 1.5 to 5.5 were proposed according to the aqueous mercury species distributions. Langmuir and Freundlich isotherm models were applied to analyze the experimental data of Hg 2+ adsorption by P-C-CTS-(Hg) and predict the relevant isotherm parameters. The best interpretation was given by the Freundlich isotherm equation. The kinetic adsorptions were well described by a pseudo-secondorder reaction model. Furthermore, the results of selectivity adsorption suggested that P-C-CTS-(Hg) possessed good adsorption selectivity for Hg 2+ in the presence of Pb 2+ because of the employment of Hg 2+ -imprinted technology. The regeneration and reutilization of P-C-CTS-(Hg) were investigated. The results showed that the adsorption capacity and adsorption property remained stable after eight reuse cycles.

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