Advanced Materials Research Vols. 113-116

Abstract: The floc formation time and order were identified with the laser method while three kinds of coagulants such as polyaluminum chloride, ferric chloride, and aluminum sulfate were tested for comparison of their coagulation process. Floc formation time of three coagulants tended to decrease with the increase of coagulant dose and turbidity. When the pH was 7, floc formation time of PAC、Al2(SO4)3 were smaller than that of other pH conditions. The minimum formation time of FeCl3 occurred when the pH was 6. The minimum dose for floc formation was 0.68, 0.88, and 1.04 mg/L for PAC, FeCl3, and Al2(SO4)3, respectively. It was also found that the floc formation order of PAC was the largest among three coagulants.

Abstract: Thermagravimetric and combustion characteristics of binderless fiberboard (BF) were investigated. Fibers prepared by traditional heat grinding (FB) and which prepared in the presence of trivial inorganic acid during grinding (FBA) were used as compared. The results show that the total weight lost during thermal decomposition following as: BF > FBA > FB. The order of initial decomposition temperature was that FB > BF > FBA. Thermagravimetric weight loss rate in pyrolysis of woodfiber and binderless fiberboard got from adding minim inorganic acid in the heat grinding system to heat grinding were faster compared to the woodfiber made by heat grinding. Combustion characteristics results revealed that heat release rate and total heat release amount of BF were larger than that of FB. Smoking ratio of BF was larger than that of FB before the flaming combustion, but t less than that of FB after the flaming combustion. The concentration of produced CO2 and CO for BF during combustion was higher than FB.

Abstract: Lactic acid production using Lactobacillus casei and Streptococcus thermophilus individually or as mixed culture on distiller’s grain in open fermentation conditions was evaluated. Lactic acid production and residual sugar were the main features examined. Increased lactic acid production was observed, when mixed cultures were used in comparison to individual ones. This revealed possible synergistic effects between the two lactic acid bacteria.

Abstract: There are three freshwaters, namely Majiagou river, Hejiagou river and Xinyigou river in Harbin city, the Hejiagou river has been seriously polluted due to no renovation conducted, which causes great impact on water quality after discharging into the Songhua River and results in water functional decline.The article focuses on the study on water environmental bearing capacity of Hejiagou river so as to provide references for comprehensive treatment of Hejiagou river.

Abstract: In order to reduce the costs of production and increase the lactic acid yields, this research adopts Bacillus subtilis to substitute enzymes. The method used in the study is two-phase fermentation - inoculate Bacillus subtilis to food waste to produce sugar, and then inoculate Lactobacillus to food waste to yield lactic acid. 87.22 g l–1 of total sugar can be obtained from non-autoclaved food waste in 30 h of saccharification at 40 centigrade. After two-phase fermentation, the optimal lactic acid concentration was 50.77g/L. The results indicate that two-phase fermentation is better than synchronous saccharification fermentation.

Abstract: Biodegradation of azo dyes usually started in anaerobic conditions with a reductive cleavage of the azo bond. Some reductive processes take place also in presence of molecular oxygen, a one-step azo dye degrading process had been investigated. A microbial consortium able to degrade Acid red B in aerobic and microaerophilic conditions had been selected. The optimal decolorization rate of Acid red B had been completely degraded under the condition of shaking for 14h and resting for 22h. Different concentrations of trace metal had been studied to determine the best condition for biodegradation after 36h inoculation. With the optimal concentration of ten trace metals, the Acid red B decolorizing efficiency was increased by Corynebacterium variabile.

Abstract: The multi-walled carbon nanotubes (MCNTs) are used as an adsorbent to remove humic acid (HA) from boiler feedwater. The experiment carries on in different temperatures, different MCNTs dosages, different pH value and different HA initial concentration to study adsorption HA property by MCNTs. The adsorption kinetics is well fitted with pseudo-second-order rate model, the adsorption mechanism is mainly attributed to the π-π electron-donor-acceptor interaction between the aromatic ring of HA and the surface carboxylic groups of MCNTs. The adsorption isotherms are fitted better with Langmuir than Freundlich models, the parameters of equilibrium constant, standard free energy (ΔG), standard enthalpy (ΔH), and standard entropy changes (ΔS) are calculated according to experiments, which shows adsorption of HA onto PAC is an exothermic process.

Abstract: In this paper, the Pinus koraiensis plantation at mountainous region in Heilongjiang Province is the research object. Four different types of water in Pinus koraiensis plantation including rainfall, throughfall, stemflow and runoff are respectively selected to study the influence of Pinus koraiensis plantation on the water quality from May to November of 2004. The indicator included pH, Do, TURB, TDS, COND, ORP, K, Na, Ca, Mg, Cu, Zn, Mn and Fe. The results show that the chemical properties of rainfall have been changed after it passing through forest canopy. The value of pH, Do and ORP in throughfall are lower than those of rainfall, the value of TURB and TDS increase obviously, 3.2 and 6.4 times higher than the rainfall. The concentrations of Na, Ca and Zn in the throughfall are lower than those in the rainfall but other metal elements show higher concentrations. The value of pH and Do in stemflow are lower than other water. The element contents in stemflow increase greatly except Cu. The values of pH, TURB, TDS and COND in the runoff are higher than those in stemflow, throughfall and rainfall. The variance of pH and Do don’t change significantly, and the variance coefficients of pH and Do are lower in rainfall, throughfall, stemflow and runoff. The value of TURB, TDS and COND vary remarkably, and the variance coefficients of which are higher. The leaching coefficient of throughfall is in the following order: K>Mg>Mn>Fe>Cu>Na>Zn>Ca. The leaching coefficient of stemflow is in the order of Fe>Mn>Mg>K>Na>Ca>Cu>Zn. After atmospheric precipitation passing through the Pinus koraiensis plantation, the value of pH in the throughfall, stemflow and runoff increase gradually closer to neutral, which shows that the Pinus koraiensis plantation have good buffer function to the acidification of the water.

Abstract: Using sewage sludge to manufacture green high performance haydite was investigated. Sewage sludge was blended with fly ash and river silt, made into raw haydite pellets and sintered. The haydite properties of different mix proportions and sinter parameters were studied. Then microstructure analysis and toxicity characteristic leaching procedure (TCLP) were performed. Results show that reducing sludge percentage of raw pellets decreases water absorption, also makes particle strength and apparent density raise. Increasing preheat temperature enhances particle strength and density while reduces water absorption. Sintered with optimum parameters, density grade of sludge haydite is 700, water absorption is 0.6%, and cylinder compressive strength is 6.6MPa. Microstructure analysis shows enamel surface and internal fine porous structure make haydite lightweight, high strength and low water absorption. And TCLP results show traces of heavy metal content are found in sludge haydite.

Abstract: The aim of this paper is to study on how to control VOC emissions from wood-based panel manufacturing. Total volatile organic compounds (TVOC) emissions from larch particleboard under different processing conditions were collected by an environmental chamber. VOC samples were prepared by desiccator, adsorbed by activated carbon, desorpted with Methylene dichloride and measured by GC/MS. The result showed that the optimal process parameters were single-layer structure, moisture content of 6%, density of 0.60 g•cm-3, thickness of 8mm, resin content of 7%, hot-pressing time of 4min.TVOC increased with board density going up，hot-pressing time increasing, moisture content and resin content rising. The predominant compounds emissions from the particleboards are aromatic compound and hydrocarbon. 24 kinds of compounds were identified from the standard board. With hydrocarbon decreasing, aromatic VOC type increased.