Advanced Materials Research Vols. 356-360

Abstract: Due to their large surface areas, high pore volumes, relatively even distributions of pore sizes, surfaces enriched with unsaturated groups and orderly long-range structures, the mesoporous materials have been widely applied in industries such as chemical, biomedical, environmental protection and functional materials. In recent years, many scientists have demonstrated that the mesoporous molecular sieves have better adsorption of dyes in wastewater. This paper reviews the applications of different types of mesoporous adsorbents for removal of dyes in wastewater. It also presents the challenges and prospects in using the mesoporous materials for dye removal in wastewater treatment.

Abstract: The Kinetics and thermodynamic was studied in ammonia nitrogen adsorption experiment using bamboo charcoal. The results showed that the dynamical data fit well with the pseudo-second-order kinetic model. The positive value of ΔH° (42.065 kJ/mol) and the apparent activation energy of the reaction of adsorption (20.67 kJ/mol) indicated that adsorption apparent rate constant increased with increasing temperature.

Abstract: Formalin (formaldehyde solution) is generally used as embalming fluid and tissue fixation agent because of its low price, antiseptic sterilization ability and good application effect and so on. However, the intense excitant odor of the formaldehyde and its volatile cause great harm for human health and working environment. In order to solve the problems caused by formaldehyde, an improved non-formaldehyde tissue preservative is invented. The preservative is a blend of acid, buffer solution and cross-linking agent, which act as mildew preventive, stabilizer and fixative respectively. The improved preservative is characterized and applied on animal and body tissue fixation and preservation. The results show that the improved preservative is a more desirable tissue preservative than formaldehyde not only due to its good mildew proof, low volatile and odor, but also the same preservation and fixation effects as formaldehyde. It will be considered as a real environmental friendly preservative in near future.

Abstract: Development of the sol-gel films for painting pretreatment of aluminium alloy is to replace bichromate conversion films such as Alodine. Corrosion resistance of Alodine film and sol-gel film were evaluated through potentiodynamic polarization curves, electrochemical impedance spectroscopy, salt spraying and acidic dropping solution. Sol-gel film is almost the same as Alodine film at the film surface density, salt spraying resistance and adhesion with painting coating. Changing color times of dropping solution on sol-gel film is shorter than Alodine film. But the corrosion current of sol-gel film is lower than Alodine and the impedance value is higher than Alodine in 35g/L NaCl solution. Mechanism of corrosion resistance of alumina sol-gel film is that the cathode reaction and anodic reactions are restrained by sol-gel film in the Cl- corrosive medium. The EIS of sol-gel film consisted of only a single capacitive arc with one time constant. Sol-gel coating can prevent or delay the corrosive solution from infiltrating the substrate for its better isolation function, thus protecting 2024 aluminium alloy from corrosion. Sol-gel films can improve corrosion resistance of aluminum alloy and have the same adhesion as Alodine film. It will be a promising alternative pretreatment for aluminum alloys prior to painting.

Abstract: The bentonite coated chitosan which was prepared of natural bentonite used as raw material and chitosan used as modifying agent applied in the treatment of livestock wastewater. The optimal preparation conditions were obtained and the removal rate of the ammonia nitrogen and COD were 73.09% and 88.94% respectively which raw concentration were 27520mg/L and 2060mg/L by orthogonal experiment. Langmuir isothermal adsorption model and the pseudo-second-order kinetic equation could describe the adsorption process accurately.

Abstract: Novel Schiff base-functionalized SBA-15 mesoporous silica is prepared, characterized and used as an adsorbent for heavy metal ion, Cu (II). The organic-inorganic hybrid mesoporous materials have been synthesized by two post-graftings of tetraethoxysilane (TEOS) with 3-aminopropyltrimethoxy-silane (APTES) and salicylaldehyde in sequence. The functionalized mesoporous materials are characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and nitrogen (N₂) adsorption-desorption analysis. The result indicates that, after sequent chemical modifications of aminopropyl and schiff base, the primary hexagonally ordered mesoporous structure of SBA-15 is not affected. The mesoporous silica, which has a BET surface area of 573.263 m² g^-1, a high pore diameter (centered at 5.24 nm) and pore volume of 0.847 cm3 g-1, exhibits the excellent adsorption capacity. The removal rate of Cu²⁺ in aqueous media is high and the adsorbent can be regenerated by EDTA and acid treatments without changing its properties.

Abstract: Microstructures of woodceramics were performed by scanning electron microscopy (SEM) and X-ray diffraction(XRD). The effect of carbonization temperature on carbon yield ratio，volume shrinkage ratio and volume electrical resistivity of woodceramics were investigated. The results show that carbonization temperature has a significant effect on the microstructure of woodceramics. The volume shrinkage ratio increases, and the carbon yield ratio and the volume electrical resistivity decrease, as the carbonization temperature increases.

Abstract: With the development of printing and dyeing industry, the nation has become the world's largest dye production and use country. With the complex composition and high color, the dyeing wastewater was currently recognized as one of the more difficult industrial wastewater to deal with. The bentonites was modified by PDMDAAC and applied into the treatment of dyeing wastewater. The treatment process was optimized with the index of decoloration rate. The decoloration rate reached 99.76% under the optimized conditions of adsorbent dosage=2g/L, pH=11, adsorption time=80min, stirring speed=350r/min, solution concentrate=500mg/L. The orthogonal experiment was designed to investigate the interaction between various reaction conditions. The superiority of PDMDAAC modified bentonite was confirmed by the comparing experiment.

Abstract: The waste coal fly ash was utilized to synthesize zeolite by alkaline fusion method through orthogonal test. The copper oxide was loaded on the zeolite by dipping method. The optimal ratio of coal fly ash to sodium hydroxide, ratio of liquid to solid, calcining temperature and crystallization time were determined to be 1.2, 9, 700°C and 10 h, respectively. The CuO dipped zeolite was applied to treat the acid red GR wastewater and the obtained color and COD removal rates were 83.80% and 99.88%, respectively. The XRD pattern showed that the NaA type zeolite phase was formed in the experiment.

Abstract: The waste wood dust was utilized to prepare the copper oxide loaded activated carbon for the treatment of the printing and dyeing wastewater (acid red GR wastewater). The response surface assisted with Design-Expert 7.0 software was used to optimize the process. The secondary multiple regression models for the color and COD removal rates were established and proven to be significant. The optimum process conditions determined by the software were: copper nitrate (0.5mol/L) 15mL, ratio of liquid to solid 56, activation temperature 690 °C and activation time 2.1h, under which the color and COD removal rates reached 99.8% and 88.34%, respectively.