Advanced Materials Research Vols. 518-523

Abstract: Activated carbon fibers (ACFs) supported La-S/TiO₂ nanocomposite photocatalyst was successfully prepared by coating-calcining method. The surface morphology, microstructure and optic properties of the sample were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area and UV–Vis diffuse reflectance spectroscopy (UV–Vis). The characteristic results confirmed that La-S/TiO₂ powders were deposited on activated carbon fiber homogeneously, and the micrographic structure and surface properties of ACFs had not been damaged by the deposition process and calcination at high temperatures. Furthermore, anatase-form TiO₂ was uniquely developed even as calcination temperatures reached 700°C. Experiments indicated that the ACFs supported La-S/TiO₂ nanocomposite photocatalyst calcined at 450°C for 2h showed higher photocatalytic activity in photodegradation of phenol aqueous solution than La-S/TiO₂ powder catalyst. The improvement may be explained in terms of synergetic effect on the stronger adsorption ability of ACFs and efficient photocatalytic performance of La-S/TiO₂.

Abstract: Poly(vinylidene fluoride) (PVDF) powder was treated with aqueous sodium hydroxide to obtain partially defluorinated fluoropolymers with expected properties such as improved hydrophilicity and fouling resistance (used as membrane material). The effects of concentration of aqueous sodium hydroxide were investigated. The results showed that the membrane’s hydrophilicity increased with increase of the fraction of alkaline treated PVDF powder. The fouling potential also decreased with the increase of the fraction of alkaline treated PVDF powder.

Abstract: Abstract. Poly(ethylene terephthalate)(PET)/poly(trimethylene terephthalate) (PTT) and PET/PTT /montmorillonite(MMT) nanocomposites were prepared by melt blending through a co-rotating twin screw extruder. Their morphology was characterized by Scanning Electron Microscope(SEM). And the nonisothermal crystallization behavior was studied by Differential Scanning Calorimetry(DSC). The results indicated that MMT dispersed homogeneously in the PTT matrix; the crystallization onset temperature(Tonset) and the crystallization peak temperature(Tp) in crystallization exotherms of PET/ PTT/MMT nanocomposites shifted to higher temperature as MMT content increased, which proved MMT acted as heterogeneous nucleating agent, and the crystallization behavior became imperfect as the cooling rate increased.

Abstract: The TiO2/NiFe2O4 (TN) composite nanoparticles with different mass ratios of NiFe2O4 to TiO2 were prepared via sol-gel method. X-ray diffraction was used to characterize the phase structure of TN. The results indicated that adulterating a smidgen of NiFe2O4 into the TiO2 (about 0.1%) can promote the phase transformation of TiO2, however, when the doping amount of NiFe2O4 surpasses 1%, the introduction of NiFe2O4 can inhibit the growth of TiO2 crystal grain and reduce the size of TiO2 crystal grain. The degradation experiment of methyl orange solution under UV illumination (253.7 nm) showed that the content of NiFe2O4 in the TN was higher, the photocatalytic activity of TN was worse, and the 0.1% TiO2/NiFe2O4 calcined at 400 °C presented the best photocatalytic activity.

Abstract: The preparation of polymeric aluminum chloride(PAC) uses industrial waste coal gangue as raw materials was studied. The effects of reaction conditions such as roasting temperature, acid molar ratio, concentration of hydrochloric acid and acid leaching time were studied, the ideal reaction conditions for the preparation of PAC was determined. The result of the experiment for treating wastewater shows that the performance of PAC prepared from coal gangue is much better than that of commercial PAC.

Abstract: Potassium ferrate has good application prospect in water treatment owing to its strong oxidation in the entire pH range and its decomposition Fe³⁺ with the characteristics of non-toxic and good coagulation effect of flocculation, etc. In this paper, the main material is calcium hypochlorite, which is used to optimize the preparation of potassium ferrate by traditional hypochlorite oxidation methods without applying chlorine in addition. XRD and IR were used to characterize the final product-potassium ferrate; while the concentration of potassium ferrate solution is determined using direct spectrophotometric method for quantitative analysis during the reaction system. The results show that the reaction temperature 25 °C, re-crystallization temperature -5 °C and reaction time 40 minutes will make yield up to 80% and the purity of the product to 97%. As the representitive substance of polycyclic aromatic hydrocarbon (PAHs), Phenanthrene can be used as target object in the analysis of K2FeO4’ oxidation property when pH is 9.5 and illuminated by xenon lamp. The result shows that as reaction concentration is 10mg/L, phenanthrene’s degradation effect becomes very obvious while accumilative degradation ratio reaches up to 65.5% after 60 mins of system reaction.

Abstract: Two kinds of new type of strong alkali anion exchange fibers (PP-g-Vam-ETA and PP-g-Vam-DAC) have been prepared non-toxically and easily via the quaternary reaction of PP-g-Vam matrix (a kind of weakly basic anion-exchange fiber, produced by our Lab.) with ETA (2,3-epoxypropyl trimethyl ammonium chloride) and the grafting reaction of PP-g-Vam matrix with DAC (acyrloxyethyl trimethylammonium chloride). The exchange capacities of PP-g-Vam-ETA and PP-g-Vam-DAC are 2.1018mmol/g (dry fiber) and 2.0217mmol/g (dry fiber) resp. Its adsorption and desorption performances for NO₃^- have been studied. The adsorption isotherm curve has been well described by Langmuir equation. The fibers have selective adsorption property for NO₃^-. The static adsorption capacity of PP-g-Vam-ETA is 11.24 mg/g (dry fiber at pH=3); and PP-g-Vam-DAC is 9.79 mg/g (dry fiber at pH=4). The static desorption rate of the two fibers are above 97%.

Abstract: CAL beads were made by dropping wise mixture of chitosan and alumina into NaOH solution. Effects of contact time, adsorbent dosage, initial concentration and pH on fluoride removal were carried out by batch experiments. Results show that adsorption rate was relatively rapid in the first 6 h, thereafter distinctly decreased until adsorption reached the equilibrium within 48 h, at this time, adsorption capacity was up to 0.67 mg/g, which was much higher than raw chitosan (0.052 mg/g). Fluoride removal increased significantly with an increase of adsorbent dosage, however, it rose slowly when the adsorbent dosage was above 16 g/L. Adsorption capacity reduced from 0.75 mg/g to 0.64mg/g when solution pH rose from 4 to 7, nevertheless, adsorption was relatively independent on solution pH between 7 and 10.

Abstract: The new purifying agent named granulated fly ash was used to absorb the organic dyes-ethylene blue, direct red 12B and reactive brilliant orange X-GN in solution in this paper. The effects of dosage, temperature and pH on adsorption and discolor were separately studied. In addition, the adsorption model was also analyzed. Experiment results showed that adsorption isotherm models of ethylene blue and direct red 12B on the new agent conformed to Freundlich equation, and reactive brilliant orange X-GN conformed to Langmuir equation; The adsorption kinetics models of ethylene blue, direct red 12B and reactive brilliant orange X-GN on the new agent conformed to pseudo-secondary kinetic equation, liquid film diffusion was the main control step for adsorption of the three dyes.

Abstract: To provide instructive information for biochar research based on utilization of agricultural residues scientifically, we investigated physical and chemical properties of different biochars. According to a registered patent method from our institute, and a simple corncob pellet kiln and relevant biochar prepare method, we chose maize straw, rice hull and corncob et al. as raw materials and measured micro-structure, element composition, specific surface area, total pore volume and average pore diameter of these materials. Results showed that biochars from all materials behaved smoothly, clear structure and average C content 60%, average ash content less than 33%. All biochars were alkaline. With high porosity, peanut hull biochar and mushroom matrix biochar tended to be designed as fertilizer carrier in agriculture. In terms of nutrients analysis, maize straw and corncob were qualified to be applied to low potassium content and low pH soil, but rice hull biochar should be used on low phosphorous content soil. There would be a wide applying spectrum of soil for rice straw biochar.