Chromium is a common harmful pollutant with high toxicity and low bearing capacity of soil and water. Excellent salinity resistance, a wide pH range, and high regeneration capacity were essential for qualified adsorbents used in removing hexavalent chromium (Cr(VI)) from polluted water. Herein, iron oxalate modified weak basic resin (IO@D301) for the removal of Cr(VI) was prepared by the impregnation method. The IO@D301 was characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Owing to abundant amine, carboxyl groups and iron ions existing on the surface, IO@D301 possesses high adsorption and salinity resistance capacity for Cr(VI). The maximum adsorption capacity of IO301 towards Cr(VI) reached 201.30 mg·g −1 at 293 K and a pH of 5. The adsorption equilibrium was well fitted by the Freundlich model, and the adsorption process was described by the pseudo-first-order kinetics model as spontaneous and exothermic. The mechanism may be identified as electrostatic attraction, coordination, and reduction, which was confirmed by FT-IR and X-ray photoelectron spectroscopy.
Gang Wang,Zengxi Li,Liu Fan,Chunshan Li,Suojiang Zhang
S ec -amines catalyzed two-step Mannich reaction for preparation of methacrolein from propionaldehyde and formaldehyde was more attractive than the C 4 selective oxidation route. Herein, a novel continuous fixed-bed process was developed for direct preparation of methacrolein from above stocks with catalysis of sec -amine grafted D301 resin. The effect of resin, sec -amine structure and grafting percentage on catalytic performance of the modified resin were detailed investigated and demonstrated by using FT-IR, TG-DTA, titration and solid-state NMR characterization methods before the optimal conditions were obtained. The grafting percentage of amine with abundant sec -amino groups onto D301 resin could reach 93.7% at optimal condition. With this new strategy, the yield and selectivity of methacrolein could attain 40.2% and 99.3%. In addition, the Mannich reaction step with activation energy of 66.3 kJ/mol was determined as the rate-controlling step through mechanism-based kinetic calculation.
Amino acid functionalized D301 resins (Tyr-D301, Phe-D301, and Ala-D301) are successfully prepared to remove phenols. The influences of adsorption condition on adsorption ability and the practical application value are investigated. The functionalized D301 resins possess strong adsorption ability toward phenol by ways of hydrogen bond interaction. The adsorption capacity of Tyr-D301, Phe-D301, and Ala-D301 is 388.2, 368.4, and 321.5 mg· g−1 at 293 K and pH of 2, respectively. The adsorption process could be described satisfactorily by Lagergren-first-order model and Langmuir model. The rate constant is 0.057, 0.042, and 0.035 min−1, respectively. The functionalized D301 can be used to dispose wastewater containing phenols.
危险品化学品经营许可证（带存储）