Advanced Materials Research Vols. 550-553

Abstract: The factor influencing on the mixed bacteria to degrade wastewater containing poly-containing conditions were optimized. Crude oil as a source of carbon, the effects of nitrogen sources, phosphorus sources, time, inoculation amount, temperature, mineralization content, initial pH value and activation time on degrading poly-containing wastewater were investigated by experiment of single factor and orthogonal experiments. The optimum process conditions were as follows: polyacrylamide (HPAM) which comes from waste water as a source of nitrogen, without other nitrogen source, K₂HPO₄ was phosphorus sources, the microorganisms activation time was 2, incubation time was 3d, initial pH value was 7, the inoculum size was 5%(v/v), incubation temperature was 35°C, the mineralization degree was 4000 mg•L-1. The main factors affecting degradation rate was nitrogen sources, time, pH, activation time, inoculum size and mineralization content.

Abstract: In order to further improve the effect on microbe degrading polyacrylamide(HPAM), this paper presented combined process of the microbial degradation of poly-containing wastewater, the innovation of this paper was added to the combination process by immobilized particles, immobilization granules were prepared by the mixed bacterium, simulation experiment on the treatment of poly-containing wastewater was done. Process simulation experiments was divided into components including static and dynamics, biochemical capacity was adjusted by static experiment, wastewater after adjustment was biochemical. After dynamic simulation experiment, the effluent quality indicators tended to be stable after 3d, degradation rate of HPAM was 79.5%, crude oil removal rate was 98.7% and the removal rate of COD_Cr was 86.4%, which attained the National Secondary Emission Standard.

Abstract: Analyze the rheology of recycled asphalts used by three rejuvenators：R1、R2、R3，the study of recycled asphalt's rheological behavior adopt BBR(Bending Beam Rheometer) and DSR(Dynamic Shear Rheometer). From the result of experiment：the usage of rejuvenator reduce the asphalt ability of anti-tracking under high temperature, some of them can even recover to the level of fresh asphalt；the mix of rejuvenators improve largely the asphalt ability of resistance to fatigue and the ability of anti-cracking under low temperature.

Abstract: Pesticide residue grade solvents have the characteristic of ultra high purity, low UV value, low pH value, low moisture content and low evaporation residue, which do not have those controlled impurity peak in pesticide chromatographic detection. This project is funded by the China government to develop the industrialization process of pesticide residue grade n-hexane, in which the industrial n-Hexane is used as crude purified by decoloration, distillation and filtration process. The products are validated by National Research Center for Environmental Analysis and Measurement (CNEAC), National Research Center for Geoanalysis, Chinese Academy of Inspection and Quarantine (CAIQ), Chinese Academy of Agricultural Sciences (CAAS) and other government originations for polychlorinated biphenyls, organochlorine pesticide or chiral pesticides analysis and further confirmed that it’s competitive to all others imported n-Hexane currently occupied in China. The optimized process parameters are: firstly utilizing 2% of silicon dioxide as decoloration agent then rinsed with distillation water before distillation. The heating temperature of two distillation towers is 88°C with reflux ratio of 15:1 and 4:1 respectively, the discharge rate of heavy component is 20 mL/min, the yield of this process is approximately 70%. This patented technique will meet pesticide residue grade n-Hexane market in China and seek for cooperation globally.

Abstract: With the development of chemical and related industry, the quantity of high-strength organic wastewater is growing, which could cause a bigger threat to human health, so it becomes very urgent and essential to research and develop new applicable wastewater treatment technology. The treatment techniques of high-strength organic wastewater at home and abroad were summarized: physical and chemical methods, biological methods and the combined process. The technological process, characters and principle of every method were introduced. These wastewater treatment technologies have some advantages of completely mineralization and degradation of the pollutants, and low risk of secondary pollution. They also have many disadvantages of complex technological process and higher operating cost. Finally, the direction of the research on two-phase combined process was pointed out.

Abstract: Photodegradation of dimethyl phthalate (DMP) in aqueous solutions by Fe(III)/oxalate/H₂O₂ system was investigated using daylight lamps as main light source. The UV-Vis spectra of the system and the concentration of •OH generated during irradiation were detected. The influences such as light sources, initial pH value, initial concentration of reactants on photodegradation efficiency of DMP were discussed. This system has advantage in appling visible light to produce •OH. DMP degradation efficiency principally depend on the concentration of •OH produced from photochemical process of the system. Several light sources including daylight lamps, metal halide lamps, UV disinfecting lamp and sunlight can all be as the light sources to achieve DMP degradation. DMP degradation efficiency keeps on a high level over the range of pH 3.0 to 5.0 and the optimum pH is 3.0. The degradation rate of DMP increases with increase of the initial concentrations of Fe(III) and H₂O₂, whereas decreases with increase of the initial concentrations of oxalate.

Abstract: At present, it is so prominent in the development of the petrochemical industry in China，and it is accompanied by petrochemical wastewater, which has become a big problem need to solve urgently.Because petrochemical wastewater mainly contains benzene-compound, organic matter, high salt wastewater and oil sewage, etc. They are very damaging and highly contaminated. The composition and properties of the petrochemical wastewater were introduced firstly, the current situation of petrochemical wastewater treatment at home and abroad were reviewed in the study. Especially the development of petrochemical industry in sichuan was introduced. Based on the present situation and the existing problems, put forward some countermeasures and expect technique develop direction in the future.

Abstract: This study presents the preparation of corncob-based bio-char and its application in adsorptive removal of three basic dyes (methylene blue, crystal violet and basic fuchsin) from aqueous solution. The adsorption behavior of basic dyes on bio-char was investigated via batch experiments. Experimental results showed that the adsorption efficiency of bio-char increased with increasing solution pH and temperature. Thermodynamic parameters demonstrated the spontaneous and endothermic nature of the adsorption. The dye removal process fitted the Langmuir isotherm well. The adsorption capacity of bio-char for methylene blue, crystal Violet and basic fuchsin at 25°C was calculated to be 126.58, 81.96 and 75.18 mg/g, respectively.

Abstract: This study utilizes chitin to remove dissolved Cu(II) from aqueous solutions. The effects of the dissolved Cu(II) concentration, chitin dosage, and pH on adsorption of dissolved Cu(II) by chitin are determined. Adsorption capacity for 20 and 80 mg/L dissolved Cu(II) onto chitin (2 g/L) was 3.86 mg/g and 5.12 mg/g, respectively. The dissolved Cu(II) adsorption percentage increased from 39% to 70% when the chitin dosage was increased from 2 g/L to 4 g/L. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. Analytical results demonstrate that the Freundlich isotherm fitted experimental results better than did the Langmuir isotherm. Enthalpy (ΔH0) and entropy (ΔS0) for dissolved Cu(II) adsorption were 8.46 kJ/mol and 123.1 J/mol.K, respectively.

Abstract: A novel organic-inorganic composite sodium polyacrylate-humic acid-rectorite was prepared by polymerization reaction of acrylic acid, humic acid and rectorite in aqueous solution and used as adsorbent for removal of heavy metals Pb(II), Cd(II), Cu(II) and Zn(II) ions from aqueous solution. The effects of contact time, pH, temperature and adsorbent dosage on adsorption capability were investigated. Adsorption kinetics, adsorption isotherm and desorption of adsorbed heavy metal ions were also researched. The results indicated that the adsorption reaction of heavy metals was rapid and reached equilibrium in 30 min. Adsorption capacities of heavy metals increased with increasing initial pH, temperature and adsorbent dosage. Adsorption reaction is endothermic. The optimum pH for all the four ions adsorption was observed at 5.5-6.5. The removal rate of Pb(II), Cd(II), Cu(II) ions with initial concentration of 50mg/L are more than 98%, and Zn(II) ions removal is about 90%. The suitability of adsorption kinetics for heavy metals to a pseudo-second-order kinetics model suggested that the adsorption rate may be governed by chemiadsorption involving ions exchange or sharing between adsorbent and metal ions. The adsorption equilibrium data was well interpreted by Langmuir and Freundlich isotherm model. The adsorption behaved as monomolecular layer. The maximum monolayer adsorption capacity was 1666.7, 666.7, 303.0 and 454.6 mg∙g-1 for Pb(II), Cd(II), Cu(II) and Zn(II) ions, respectively, at 25°C. Adsorbed metal ions were desorbed effectively by 0.1M HCl solution. Desorption rate was about 95.2, 92.4, 98.7 and 94.3% for Pb(II), Cd(II), Cu(II) and Zn(II) ions, respectively. Adsorbent can be reused for three cycles without any significant loss in adsorption performance.