Advanced Materials Research Vols. 356-360

Abstract: For the surficial sediments sampled from the Shaxi River in Sanming, Fujian Province, China, the distribution characteristic of heavy metal copper in surficial sediments were investigated. The microwave digestion result showed that the concentration of Cu in surficial sediments ranged from 26.95 mg/kg to 74.76 mg/kg. The results of modified BCR sequential extraction procedure showed that heavy metal copper in the surficial sediment was mainly associated with residual and reducible fractions. The fractions of copper sampled near the wastewater discharge were in the order of residual > reducible > oxidizable > acid soluble > water soluble fraction, and in the order of residual > reducible > acid soluble > oxidizable > water soluble fraction in samples away from the wastewater discharge. The results indicated that the concentration and fraction of pollutant copper were significantly correlative to the wastewater discharge of some iron and steel factory around the Shaxi River, which varied obviously with the downstream distance increasing to the wastewater discharge. The reducible and oxidizable fractions decreased with the downstream distance increasing to the wastewater discharge of iron and steel factory, however, the acid soluble fraction increased with the distance increasing.

Abstract: Near surface disposal of low and intermediate level radioactive waste (LILW) requires a detailed site investigation of the potential sites, in which the transport behavior of solutes in the groundwater system is one of the key processes that needed to be addressed. An investigation is undertaking for the disposal of LILW at a potential site in Southern China. In-situ test have been conducted to study the hydrogeologic characteristics of the site. Firstly, tests including pit permeability tests, injecting tests, water pressure tests, pumping tests and laboratory permeability tests have been performed according to the specific field conditions. Hydraulic conductivities for different layers of rock and soils have been calculated and their recommended values have been presented. And then in-situ dispersion tests have been performed at an area adjacent to the disposal site with non-sorbed tracers. A numerical model has been developed for the site based on data obtained during the site investigation, and has been calibrated with available measured groundwater level and measured tracer concentrations in the dispersion tests. Calibrated results indicate that the longitudinal dispersion coefficient is equal to 5.0×10-3 m²/d. Preliminary predictions have been performed for the groundwater flow and solute advection-dispersion behavior according to the design of the site, in which the center valley will be backfilled with low permeable materials. Predicted results indicate that the groundwater exhibits a lower water table and a smaller hydraulic gradient under designed site condition than under natural condition. All the tracers remain underground in the site and transport slowly mainly through advection and dispersion. Finally, conclusions for the study have been presented and the key tasks for future work have been discussed. This study provides an insight understanding of the hydrogeology characteristics of the disposal site and is useful for the assessment of environment impacts of the site under disposal of LILW.

Abstract: The effect of addition of Fructus Ligustri Lucidi Extract (FLLE) on methane production and rumen fermentation in sheep was investigated in this study. FLLE addition levels were 0, 1, 2, 3 and 4 g/L of ruminal fluid. Ruminal fluid was removed from four sheep, mixed with phosphate buffer (1:2) and incubated (30 ml) anaerobically at 38°C for 24-h with or without FLLE. Results indicated that addition of FLLE linearly decreased methane production (p<0.05), linearly decreased ammonia concentration (p<0.05), and acetate to propionate ratio (p<0.05). Data of numbers of methanogens, fungi, ciliate and cellulolytic indicated that they were linearly decreased by addition of FLLE (p<0.05). Addition of FLLE at all dosages have no effect on rumen pH value, acetate molar concentration and butyrate molar concentration (p>0.05). Addition of FLLE linearly decreased count of F. succinogenes (p<0.05). In conclusion, these results of 24-h in vitro batch culture indicated that FLLE has the ability to inhibit methane production in the rumen, stimulate rumen fermentation and suppress fiber degrading bacteria, F. succinogenes. Abbreviations: FLLE=Fructus Ligustri Lucidi extract; IVDDM=in vitro digestibility of dry matter.

Abstract: In the limestone/gypsum wet flue gas desulfurization pilot-scale test rig, key parameters such as SO₂ absorption rate, mass transfer were experimentally determined．The results show that desulphurizing capacity of gypsum and fly ash is relatively weaker, which is only equivalent to fresh limestone with a content of 0.27% and 1.5% respectively. pH-t curve of slurry with different levels of fly ash could be divided into a sharply increasing stage and a steadily increasing stage. The leaching content of Mn²⁺ is about 9 times of Fe³⁺ , Mn²⁺ can form intermediate complex with HSO3- in the solution, which can induce catalytic reaction and accelerate SO2 absorption. Fly ash in gypsum slurry can obviously promote desulfurization. The pH value of slurry is high at the initial reaction stage, and effect of fly ash on SO₂ absorption rate is less than 1.5%. when the pH value is decreased to 5.0, The leaching content of Mn2+ will grow with the decrease of pH value, better catalytic efficiency can be gained, effect of fly ash on SO2 absorption rate can increase 6.0% at most. The reaction is controlled by liquid phase resistance; the ratio of gas phase resistance to overall resistance is less than 38%. Mn²⁺ concentration of slurry increases with pH value decreasing and fly ash concentration increasing, which has significant effect on catalyzed oxidation of SO₃^2-.

Abstract: In this study, calcium alginate immobilized bacillus subtilis body was used as an adsorbent for the aim of adsorpting Cu(Ⅱ) ions form the aqueous solutions, On sutiable condition, this study use purely bacteria eliminate other bacteria come in life-form bacteria .Through the orthogonal experiment obtains the optimum condition of sodium alginate fossilization bacillus subtilus pellet to the Cu(Ⅱ) adsorption, The biosorption efficiency was strongly influenced by the pH and the initial concentration ofthe Cu(Ⅱ) aqueous solutions. We also discusses the influence of single factor to the sodium alginate fossilization bacillus subtilus pellet to the Cu(Ⅱ) adsorption ,which included pH, contact time, temperature, initial metal ion concentrations and ionic strength in the adsorption process. The adsorption of the adsorbent on Cu(Ⅱ) is related to its concentration . From the research,we know the maximum adsorption rate to the Cu(Ⅱ) is about 83.2%. Using different model to analyse data. The sorption process follows pseudo-second-order kinetics very well,and the correlation coefficients R all reached to 0.9, and the rate constant of this kinetics model for the adsorption processes, k₂, increased with the increasing temperatures. The isothermal data could be well described by the Langmuir adsorption isothermal equations．The experimental results showed that heavy metals could be eficciently accumulated by the immobilized bacteria.

Abstract: In this study, calcium alginate immobilized bean husk powder(CA) beads was used as an adsorbent for the aim of removing Pb(Ⅱ) ions form the aqueous solutions, and the effect of initial solution pH, contact time, temperature, initial metal ion concentrations and ionic strength in the adsorption process were investigated in detail. Experimental results showed that the amount of adsorbed Pb(Ⅱ) increased with the increasing initial metal ion concentration and solution pH in the examined range. The results showed that the optimum adsorption pH for Pb(Ⅱ) was5.5, the uptake was 10. 78 mg/g, the desorption rates of Pb(Ⅱ) by EDTA was calculated as 90 %. The concentration of Pb(Ⅱ)of mine wastewater reach the first class of irrigation water quality standards after the first time of adsorption treatment, and reach the first class of fishery water quality standard after the second treatment.

Abstract: Experiment was made to study heavy metal ion mining wastewater.The effect of Temperature, pH, Initial concentration, coexisting ions and time on the performance of Nanomaterials were investigated. Results showed that removal efficiency of heavy metal ions was higher than 86% after adsorption treatment of containing Cr(VI) mine wastewater, Cr(VI) concentration in permeation liquid was lower than 0.1 mg/L, and the concentration of Cr(VI) ions reaches the first class of irrigation water quality standards , which verified that Nanomaterials is effective for the removal of heavy metal ions, and the concentration liquid can be reclaimed.

Abstract: The Leptospirillum ferrooxidans which had been selected and cultivated from mine area was applied in treatment of Cr(VI) -containing waste water in the laboratory and real Cr(VI) -containing waste water. The principle of its adsorption process was probed. The results show that the main factors which affect the lead uptake are pH value、ways of pretreatment、contacting time、co-existing ions、Leptospirillum ferrooxidans concentration insolutions,etc.It was able to adsorb Cr(VI) efficiently.After adsorption steps of the treatment, the concentration of heavy metal Cr(VI) in solution met the standard for treating waste water. After adsorption treatment of containing chromium mine wastewater, the concentration of chromium ions reaches the first class of irrigation water quality standards.

Abstract: Sludge agriculture application in future will be one of the main sewage sludge disposal ways in China. To ensure safety and environment of sewage sludge agriculture application, except to strengthen the research of sludge heavy metal, pathogen outside the organic contaminants will be one of the focuses of the future research, especially to strengthen the PAHs and NP/NPE. In order to reduce the environmental risks of sludge agriculture application, using biological aerobic fermentation processing technology treatment sludge can effectively reduce the organic contaminants, depress secondary pollution problem, which sewage sludge brings.

Abstract: In order to use remediation of contaminated soil and revegetation in Huize lead-zinc mining tailings,it was significant to study of the lead-zinc tolenrance of the symbiosis of the legume-rhizobia in Huize lead-zinc mining tailings.In this paper,the tolenrance to compound lead-zinc stress of the symbiosis of the legume-rhizobia was studied. The results showed that the legume seeds grew natually in Huize lead-zinc mining tailings had the good resistence to compound lead-zinc.The host plants inoculated the two high tolenrance to lead-zinc strains HS3 and HZ8 showed that the capability of host plants to resist compound lead-zinc stress was stronger than those were not inoculated and are sensitive to metal resistence rhizobia.The HS3 and HZ8 could decrease the concentrations of lead-zinc of the surrounding surface of nodule and could be beneficial to the metal lead-zinc tolerance of the symbiosis of legume-rhizobia by the combination of the lead-zinc and the polysaccharides and many other secrations of the nodule surface.The comprehensive reaction mechanism of heavy metal tolenrance to lead-zinc of the symbiosis of legume-rhizobia HS3 and HZ8 is worth studying.