The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the abso...The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.展开更多
Researches on organization and structure in complex systems are academic and industrial fronts in modern sciences. Though many theories are tentatively proposed to analyze complex systems, we still lack a rigorous the...Researches on organization and structure in complex systems are academic and industrial fronts in modern sciences. Though many theories are tentatively proposed to analyze complex systems, we still lack a rigorous theory on them. Complex systems possess various degrees of freedom, which means that they should exhibit all kinds of structures. However, complex systems often show similar patterns and structures. Then the question arises why such similar structures appear in all kinds of complex systems. The paper outlines a theory on freedom degree compression and the existence of hierarchical self-organization for all complex systems is found. It is freedom degree compression and hierarchical self-organization that are responsible for the existence of these similar patterns or structures observed in the complex systems.展开更多
Screening of new microorganism being able to produce efficiently flocculants was carried out. A new model for screening efficient flocculant-producing strains was designed and tested. The results showed that this mode...Screening of new microorganism being able to produce efficiently flocculants was carried out. A new model for screening efficient flocculant-producing strains was designed and tested. The results showed that this model for screening efficient flocculant-producing strains is very reliable and can greatly shorten the screening period. 13 flocculant-producing strains were isolated from activated sludge by conventional method. A strain, designated as HHE6, produced the bioflocculant with the turbidity removal 98% for kaolin suspension. Six of 13 strains selected as the original strains were treated with NTG as mutagen, and five mutant strains(HHE-P7, HHE-A8, HHE-P21, HHE-P24, HHE-A26) with high flocculation efficiency was obtained by selection, which exhibited the flocculation rate for kaolin suspension above 90%. Strains HHE6, HHE-P7, and HHE-P24 were classified as Penicillium purpurogenum, HHE-P21 as Penicillium cyclopium, HHE-A26 as Aspergillus versicolor and HHE-A8 as Aspergillus fumigatus, and it is hitherto unreported for biofloccutant-producing strains of Penicillium. The growth of the six strains(HHE6, HHE-P7, HHE-A8, HHE-P21, HHE-P24, HHE-A26) had similar curves, i.e. firstly increasing rapidly, keeping relatively constant then and finally decreasing gradually with cultivation time. The production of bioflocculants by strains showed the similar pattern to strain growth.展开更多
Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed ...Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.展开更多
Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-...Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-4/Al 3+ ratio on the performance of PACS for removal of natural organic matter(NOM) with humic rich actual water was examined. It was found that PACS with SO 2- \-4/Al 3+ mole ratio of 0.0664 achieved the best NOM removal results and was selected to investigate its performance in comparison with PAC, FeCl 3 and alum(Al 2 (SO 4) 3·18H 2O). The experimental results showed that the optimum NOM removals were achieved at pH 5.0\_8.2 and the dose of about 5 0 mg/L as Al both for the selected PACS and PAC, at pH 5 0\_6 0 and the dose of about 7 0 mg/L as Fe for FeCl 3, and at pH 5 0\_7 0 and the dose of about 7 0 mg/L as Al for alum, respectively. At the optimum conditions, the selected PACS achieved the best NOM removal result, followed by PAC, FeCl 3, and then alum. The concentration of residual aluminum in treated water by the selected PACS and PAC under the optimum coagulant conditions was approximately 115 μg/L, which can completely comply with the regulated limits.展开更多
China is one of countries with the highest mercury production in the world. The Guizhou Province in Southwestern China is currently one of the world's most important mercury production areas. In order to study the...China is one of countries with the highest mercury production in the world. The Guizhou Province in Southwestern China is currently one of the world's most important mercury production areas. In order to study the neurotoxicity of rice from Qingzhen Chemical Plant area and probe into the signal transduction molecular mechanism of injury in rat brain stimulation by mercury contaminated rice. The rats were exposed to mercury contaminated rice for 20 d. Both of the measurements of NO and NOS were processed according to the protocol of the kit. The effect of Hg contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction(RT-PCR) and immunocytochemical methods. The results showed the neural transmitter NO and NOS in brain were significantly change between exposure groups and control group; the mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group(p<0.01). It could be concluded that nitric oxide was involved in mercury contaminated rice induced immediate early gene c-fos expressions in the rat brain. Through food chain, local ecosystem and health of local people iave been deteriorated seriously by mercury. This serious situation will last a long period. In order to alleviate mercury pollution, more work needs to do.展开更多
In order to study the molecular mechanism of injury in rat organs induced by methylmercury, and the relationship between neurotransmitter and oxidative damage in the toxicity process of rat injury by methylmercury was...In order to study the molecular mechanism of injury in rat organs induced by methylmercury, and the relationship between neurotransmitter and oxidative damage in the toxicity process of rat injury by methylmercury was studied. The control group was physiological saline of 0.9%, the concentration of exposure groups were 5 mg/(kg5d) and 10 mg/(kg5d) respectively. The content of AChE, ACh, NOS, NO, MDA, SOD, GSH-Px and GSH in different organs of rats were determined with conventional methods. The results showed that after exposure to methylmercury for 7 d, the mercury content in brain of exposure groups increased clearly and had significant difference compared with the control group(P<0.01). In rat's brain, serum, liver and kidney, the content of ACh and AChE were all decreased; the content of NOS and NO were all increased; the content of MDA was increased compared with the control group, the exposure groups had significant difference (P<0.01); the content of SOD, GSH and GSH-Px was decreased compared with the control group, the exposure groups had significant difference(P<0.01). It could be concluded that methylmercury did effect the change of neurotransmitter and free radical. They participated in the toxicity process of injury by methylmercury. The damage of neurotransmitter maybe cause the chaos of free radical and the chaos of free radical may also do more damage to neurotransmitter vice versa.展开更多
A kind of Levextrel resin separation process was developed for separation ofindium (III), gallium (III), and zinc (II) from aqueous sulfate solution with Levextrel resincontaining di(2-ethylhexyl) phosphoric acid (CL-...A kind of Levextrel resin separation process was developed for separation ofindium (III), gallium (III), and zinc (II) from aqueous sulfate solution with Levextrel resincontaining di(2-ethylhexyl) phosphoric acid (CL-P 204). The aim of the research is to collectpreliminary results for a pilot-scale production. Properties of adsorbing indium (III), gallium(III), and zinc (II) from sulfate solution with the Levextrel resin were first studied by batchoperation and column operation. The optimum pH, adsorption capacities and concentrations ofstripping agents for indium (III), gallium (III) were tested. The separation order of indium (III),gallium (III), and zinc (II) from sulfate solution with CL-P 204 Levextrel resin was found thatindium (III) could be first separated by adsorbing at the acidity of 1.0 mol/L whereas gallium (III)and zinc (II) could not, and they were adsorbed together by adsorbing at pH =2.8, then separatedfrom each other by stripping with 0.1 and 0.5 mol/L hydrochloric acid, respectively. The recoveriesof three metal ions were all higher than 99 percent. The cyclic properties of this resin are well.展开更多
The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. Continuous tests via a membrane bioreactor (MBR) were operated under the controlled co...The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. Continuous tests via a membrane bioreactor (MBR) were operated under the controlled conditions to proliferate the nitrifiers. Heterotrophic nitrifying bacteria were isolated from the system in which the efficiency of total nitrogen(TN) removal was up to 80%. Since no autotrophic ammonium and nitrite oxidizers could be detected by fluorescence in situ hybridization(FISH), oxidized-N production was unlikely to be catalyzed by autotrophic nitrifiers during the heterotrophic nitrifiers' isolation in this study. The batch test results indicate that the isolated heterotrophic bacteria were able to nitrify. After 3 weeks incubation, the efficiencies of the COD removal by the three isolated bacterial strains B1, B2, and B3 were 52 6%, 71 7%, and 77 7%, respectively. The efficiencies of the TN removal by B1, B2, and B3 were 35 6%, 61 2% and 68 7%, respectively.展开更多
Objective Mercury (Hg), as one of the priority pollutants and also a hot topic of frontier environmental research in many countries, has been paid higher attention in the world since the middle of the last century. Gu...Objective Mercury (Hg), as one of the priority pollutants and also a hot topic of frontier environmental research in many countries, has been paid higher attention in the world since the middle of the last century. Guizhou Province (at N24°30′-29°13′, E103°1′-109°30′, 1 100 m above the sea level, with subtropical humid climate) in southwest China is an important mercury production center. It has been found that the mercury content in most media of aquatics, soil, atmosphere and in biomass of corns, plants and animals, is higher than the national standard.The present study aims to explore the influence of mercury pollution on the health of local citizens. Methods The effect of rice from two mercury polluted experimental plots of Guizhou Province on the expression of c-jun mRNA in rat brain and c-jun protein in cortex, hippocampus and ependyma was observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. Results The results showed that the mercury polluted rice induced expression of c-jun mRNA and its protein significantly. Selenium can reduce Hg uptake, an antagonism between selenium and mercury on the expression of c-jun mRNA and c-jun protein. Conclusion c-jun participates in the toxicity process of brain injury by mercury polluted rice, the expression of c- jun mRNA in brain, and c-jun protein in rat cortex and hippocampus can predict neurotoxicity of mercury polluted rice. People should be advised to be cautious in eating any kind of Hg-polluted foods. To reveal the relationship between c-jun induction and apoptosis, further examinations are required.展开更多
Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics ...Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate were evaluated through different kinetics studies. Since chlorine was an electron withdrawing atom, the substitution of chlorine on the aromatic ring decreased the oxidation rate constant by σ-electron withdrawing conductive effect. The substitution of chlorine at ortho or para position on the aromatic ring increased the oxidation rate constant by π-electron donating conjugative effect, and the conjugative effect could counteract the negative impact of the conductive effect to some extent. On the other hand, the substitution of chlorine at ortho position on the aromatic ring decreased the oxidation rate constant by steric hindrance effect. The oxidation rate constants of phenol and chlorinated phenols studied decreased as follow order: 4-chlorophenol>2,4-dichlorophenol>phenol>2,6-dichlorophenol.展开更多
The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes...The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD Cr and NH + 4-N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, COD Cr and NH + 4-N was 79.1%, 63.9% and 96.4% respectively under the influent COD Cr and NH + 4-N of 122.1 mgCOD Cr /L and 14.84 mgNH + 4-N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3∶1.展开更多
The neurotransmitter level changes of ducks exposed 8-month in a mercury-polluted site(Wanshan, China) and a reference site(Shanghai, China) were examined. Chemical analyses showed both higher mercury and selenium con...The neurotransmitter level changes of ducks exposed 8-month in a mercury-polluted site(Wanshan, China) and a reference site(Shanghai, China) were examined. Chemical analyses showed both higher mercury and selenium concentrations in the organ of Wanshan ducks. An increased content of acetylcholine(ACh) in brain and blood and a decreased activity of acetylcholinesterase(AChE) in blood were observed. Moreover, there was an increasing trend for nitric oxide synthase(NOS) activity and nitric oxide(NO) production in duck brain, but a reduction of NOS activity in duck serum. The possible explanations were due to the interactive effect of selenium accumulation and the sublethal exposure level of mercury in Wanshan area. The present study showed that AChE and NOS were sensitive to mercury contamination of real circumstance, suggesting that these two indexes have the potential to be biomarkers in assessment of health effects by mercury contamination.展开更多
In the presence of inhibitors, the macroscopical oxidation kinetics of calcium sulfite, the main byproduct in wet limestone scrubbing, was studied for the first time by adding different inhibitors and varying pH, conc...In the presence of inhibitors, the macroscopical oxidation kinetics of calcium sulfite, the main byproduct in wet limestone scrubbing, was studied for the first time by adding different inhibitors and varying pH, concentration of calcium sulfite, oxygen partial pressure, concentration of inhibitors and temperature. The mathematical model about the general oxidation reaction was established, which was controlled by three steps involving dissolution of calcium sulfite, mass transfer of oxygen and chemical reaction in the solution. It was concluded that the general reaction was controlled by mass transfer of oxygen under uncatalyzed conditions, while it was controlled by dissolution of calcium sulfite after adding three kinds of inhibitors. Thus, the theory was provided for investigating the mechanism and oxidation kinetics of sulfite. The beneficial references were also supplied for design of oxidation technics in the wet limestone scrubbing.展开更多
The effect of additives (anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant alkyl polysaccharide glycoside (APG), and liquid hydrocarbon cyclopentane (CP)) on hydrate induction time and formation rat...The effect of additives (anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant alkyl polysaccharide glycoside (APG), and liquid hydrocarbon cyclopentane (CP)) on hydrate induction time and formation rate, and storage capacity was studied in this work. Micelle surfactant solutions were found to reduce hydrate induction time, increase methane hydrate formation rate and improve methane storage capacity in hydrates. In the presence of surfactant, hydrate could form quickly in a quiescent system and the energy costs of hydrate formation were reduced. The critical micelle concentrations of SDS and APG water solutions were found to be 300×10-6 and 500×10-6 for methane hydrate formation system respectively. The effect of anionic surfactant (SDS) on methane storage in hydrates is more pronounced compared to a nonionic surfactant (APG). CP also reduced hydrate induction time and improved hydrate formation rate, but could not improve methane storage in hydrates.展开更多
The deactivation kinetics of Pd(PPh3)2Cl2 in the monocarbonylation of benzyl chloride to synthesize phenylacetic acid is studied in this paper. Solid 1-(2-pyridylazo)-2-naphthol (PAN) is used as the colouring agent, a...The deactivation kinetics of Pd(PPh3)2Cl2 in the monocarbonylation of benzyl chloride to synthesize phenylacetic acid is studied in this paper. Solid 1-(2-pyridylazo)-2-naphthol (PAN) is used as the colouring agent, and the concentration of Pd(PPh3)2Cl2 in the system is measured through absorptiometry. The result shows that the optimum condition of the chromogenic reaction between Pd2+ and PAN is: 0.5 ml of 0.04% PAN added to 10 ml of Pd2+ solution (1.0×10-6-2.0×10-5 mol/L), and heated in a constant temperature water bath at 40℃ for about 30 min, with pH of the solution being about 3.0. The molar coefficient of absorption is 1.384×104 L/(mol·cm); the orders of the hydrolytic reaction to the concentration of Pd(PPh3)2Cl2, PPh3, phenylacetic acid and NaOH are 0.5, minus 0.8, 2 and 1.2, respectively. The activation energy (E) of the hydrolytic reaction is 75.59 kJ/mol, and the pre-exponential factor is 1.68×1012.展开更多
A strain saccharomycete STSM-1 with high flocculanting activity was isolated from activated sludge with conventional methods. The high production rate and the low cost STSM-1 medium was obtained by selecting different...A strain saccharomycete STSM-1 with high flocculanting activity was isolated from activated sludge with conventional methods. The high production rate and the low cost STSM-1 medium was obtained by selecting different kinds of media, carbon source, nitrogen source and inorganic salt ion. The best flocculant-producing conditions were found by changing medium initial pH, culture temperature and ventilation flow. The best flocculating effect was obtained by changing positive ion types, density and concentration of flocculant.展开更多
The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO 2. The ASBR was operated at four chemical oxygen ...The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO 2. The ASBR was operated at four chemical oxygen demand(COD) loading rates, 2.8, 5.1, 6.2 and 8.4 g/(L·d) respectively. The COD loading rate was increased with the TS concentration and HRT changing. At maximum COD loading rate of 8.4 g/(L·d), the COD, total solid(TS) removal rate and methane gas yield were 69%, 68% and 2.5 L/(L·d) respectively. The operation of the reactor with gas-phased absorb of CO 2 was stable in spite of the low pH(2.6—3.9) and high concentration of TS(142 g/L) of input mixture. The output volatile fatty acid(VFA) concentration was between 2.7—4.7 g/L and had no inhibition on the methanogenic microorganism. The reactor without gas-phased absorb of CO 2 became acidified when the total COD loading rate was increased to 5.1 g/(L·d). Stoichiometry of the methanogenesis for kitchen wastes showed a considerable amount of alkaline will be required to keep pH in the appropriate range for the methanogenic microorganism based on theoretical calculation. Gas-phased absorb of CO 2 effectively reduced the alkaline consumption, hence avoided excessive cation into the reactor.展开更多
The paper deals with the degradation of the organic compounds in the coke plant wastewater by the combined process of ultrasonic irradiation and activated sludge. The influence factors of the ultrasonic degradation e...The paper deals with the degradation of the organic compounds in the coke plant wastewater by the combined process of ultrasonic irradiation and activated sludge. The influence factors of the ultrasonic degradation effect such as air atmosphere, initial concentration, ultrasonic power density and the category and consumption of catalyst were investigated. A water quality model was used to explain the degradation of different kinds of organic compounds in the coke plant wastewater by ultrasonic irradiation. After the wastewater was treated by the combined process of ultrasonic irradiation and activated sludge, the COD degradation efficiency was 95.74%, which is 63.49% higher than that by the process of activated sludge alone.展开更多
Public participation has been one of important problems in the strategic environmental assessment (SEA). In this paper, the origin and the present research-conditions of public participation in SEA were analyzed. And ...Public participation has been one of important problems in the strategic environmental assessment (SEA). In this paper, the origin and the present research-conditions of public participation in SEA were analyzed. And the necessity of public participation was illuminated from following three aspects: 1) the public participation in China′s SEA is a key method of gaining the public support; 2) the public participation is one important source of gaining information; 3) the public participation is a good way to overcome the obstruction in the traditional mechanism of making strategy decision. Effective public participation should be involved in the whole process of SEA, and the public participators should include the public representatives of the groups affected by environmental change, the specialists in SEA and relevant fields, persons who are interested in the strategy and media, and so on. Various methods of public participation in SEA, including the methods of obtaining information and information feedback or consultation, were discussed. Further, the function, the advantages and the disadvantages of each method were discussed in detail, too.展开更多
文摘The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.
基金Supported by the Science Foundation of the Ministry of Education of China for the Returned Overseas Chinese Scholars
文摘Researches on organization and structure in complex systems are academic and industrial fronts in modern sciences. Though many theories are tentatively proposed to analyze complex systems, we still lack a rigorous theory on them. Complex systems possess various degrees of freedom, which means that they should exhibit all kinds of structures. However, complex systems often show similar patterns and structures. Then the question arises why such similar structures appear in all kinds of complex systems. The paper outlines a theory on freedom degree compression and the existence of hierarchical self-organization for all complex systems is found. It is freedom degree compression and hierarchical self-organization that are responsible for the existence of these similar patterns or structures observed in the complex systems.
基金The National Natural Science Foundation of China(No.50078022)
文摘Screening of new microorganism being able to produce efficiently flocculants was carried out. A new model for screening efficient flocculant-producing strains was designed and tested. The results showed that this model for screening efficient flocculant-producing strains is very reliable and can greatly shorten the screening period. 13 flocculant-producing strains were isolated from activated sludge by conventional method. A strain, designated as HHE6, produced the bioflocculant with the turbidity removal 98% for kaolin suspension. Six of 13 strains selected as the original strains were treated with NTG as mutagen, and five mutant strains(HHE-P7, HHE-A8, HHE-P21, HHE-P24, HHE-A26) with high flocculation efficiency was obtained by selection, which exhibited the flocculation rate for kaolin suspension above 90%. Strains HHE6, HHE-P7, and HHE-P24 were classified as Penicillium purpurogenum, HHE-P21 as Penicillium cyclopium, HHE-A26 as Aspergillus versicolor and HHE-A8 as Aspergillus fumigatus, and it is hitherto unreported for biofloccutant-producing strains of Penicillium. The growth of the six strains(HHE6, HHE-P7, HHE-A8, HHE-P21, HHE-P24, HHE-A26) had similar curves, i.e. firstly increasing rapidly, keeping relatively constant then and finally decreasing gradually with cultivation time. The production of bioflocculants by strains showed the similar pattern to strain growth.
文摘Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.
文摘Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-4/Al 3+ ratio on the performance of PACS for removal of natural organic matter(NOM) with humic rich actual water was examined. It was found that PACS with SO 2- \-4/Al 3+ mole ratio of 0.0664 achieved the best NOM removal results and was selected to investigate its performance in comparison with PAC, FeCl 3 and alum(Al 2 (SO 4) 3·18H 2O). The experimental results showed that the optimum NOM removals were achieved at pH 5.0\_8.2 and the dose of about 5 0 mg/L as Al both for the selected PACS and PAC, at pH 5 0\_6 0 and the dose of about 7 0 mg/L as Fe for FeCl 3, and at pH 5 0\_7 0 and the dose of about 7 0 mg/L as Al for alum, respectively. At the optimum conditions, the selected PACS achieved the best NOM removal result, followed by PAC, FeCl 3, and then alum. The concentration of residual aluminum in treated water by the selected PACS and PAC under the optimum coagulant conditions was approximately 115 μg/L, which can completely comply with the regulated limits.
文摘China is one of countries with the highest mercury production in the world. The Guizhou Province in Southwestern China is currently one of the world's most important mercury production areas. In order to study the neurotoxicity of rice from Qingzhen Chemical Plant area and probe into the signal transduction molecular mechanism of injury in rat brain stimulation by mercury contaminated rice. The rats were exposed to mercury contaminated rice for 20 d. Both of the measurements of NO and NOS were processed according to the protocol of the kit. The effect of Hg contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction(RT-PCR) and immunocytochemical methods. The results showed the neural transmitter NO and NOS in brain were significantly change between exposure groups and control group; the mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group(p<0.01). It could be concluded that nitric oxide was involved in mercury contaminated rice induced immediate early gene c-fos expressions in the rat brain. Through food chain, local ecosystem and health of local people iave been deteriorated seriously by mercury. This serious situation will last a long period. In order to alleviate mercury pollution, more work needs to do.
基金The National Natural Science Foundation of China(No. 20177013) and the Younger Research of Shanghai Jiaotong University
文摘In order to study the molecular mechanism of injury in rat organs induced by methylmercury, and the relationship between neurotransmitter and oxidative damage in the toxicity process of rat injury by methylmercury was studied. The control group was physiological saline of 0.9%, the concentration of exposure groups were 5 mg/(kg5d) and 10 mg/(kg5d) respectively. The content of AChE, ACh, NOS, NO, MDA, SOD, GSH-Px and GSH in different organs of rats were determined with conventional methods. The results showed that after exposure to methylmercury for 7 d, the mercury content in brain of exposure groups increased clearly and had significant difference compared with the control group(P<0.01). In rat's brain, serum, liver and kidney, the content of ACh and AChE were all decreased; the content of NOS and NO were all increased; the content of MDA was increased compared with the control group, the exposure groups had significant difference (P<0.01); the content of SOD, GSH and GSH-Px was decreased compared with the control group, the exposure groups had significant difference(P<0.01). It could be concluded that methylmercury did effect the change of neurotransmitter and free radical. They participated in the toxicity process of injury by methylmercury. The damage of neurotransmitter maybe cause the chaos of free radical and the chaos of free radical may also do more damage to neurotransmitter vice versa.
文摘A kind of Levextrel resin separation process was developed for separation ofindium (III), gallium (III), and zinc (II) from aqueous sulfate solution with Levextrel resincontaining di(2-ethylhexyl) phosphoric acid (CL-P 204). The aim of the research is to collectpreliminary results for a pilot-scale production. Properties of adsorbing indium (III), gallium(III), and zinc (II) from sulfate solution with the Levextrel resin were first studied by batchoperation and column operation. The optimum pH, adsorption capacities and concentrations ofstripping agents for indium (III), gallium (III) were tested. The separation order of indium (III),gallium (III), and zinc (II) from sulfate solution with CL-P 204 Levextrel resin was found thatindium (III) could be first separated by adsorbing at the acidity of 1.0 mol/L whereas gallium (III)and zinc (II) could not, and they were adsorbed together by adsorbing at pH =2.8, then separatedfrom each other by stripping with 0.1 and 0.5 mol/L hydrochloric acid, respectively. The recoveriesof three metal ions were all higher than 99 percent. The cyclic properties of this resin are well.
文摘The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. Continuous tests via a membrane bioreactor (MBR) were operated under the controlled conditions to proliferate the nitrifiers. Heterotrophic nitrifying bacteria were isolated from the system in which the efficiency of total nitrogen(TN) removal was up to 80%. Since no autotrophic ammonium and nitrite oxidizers could be detected by fluorescence in situ hybridization(FISH), oxidized-N production was unlikely to be catalyzed by autotrophic nitrifiers during the heterotrophic nitrifiers' isolation in this study. The batch test results indicate that the isolated heterotrophic bacteria were able to nitrify. After 3 weeks incubation, the efficiencies of the COD removal by the three isolated bacterial strains B1, B2, and B3 were 52 6%, 71 7%, and 77 7%, respectively. The efficiencies of the TN removal by B1, B2, and B3 were 35 6%, 61 2% and 68 7%, respectively.
文摘Objective Mercury (Hg), as one of the priority pollutants and also a hot topic of frontier environmental research in many countries, has been paid higher attention in the world since the middle of the last century. Guizhou Province (at N24°30′-29°13′, E103°1′-109°30′, 1 100 m above the sea level, with subtropical humid climate) in southwest China is an important mercury production center. It has been found that the mercury content in most media of aquatics, soil, atmosphere and in biomass of corns, plants and animals, is higher than the national standard.The present study aims to explore the influence of mercury pollution on the health of local citizens. Methods The effect of rice from two mercury polluted experimental plots of Guizhou Province on the expression of c-jun mRNA in rat brain and c-jun protein in cortex, hippocampus and ependyma was observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. Results The results showed that the mercury polluted rice induced expression of c-jun mRNA and its protein significantly. Selenium can reduce Hg uptake, an antagonism between selenium and mercury on the expression of c-jun mRNA and c-jun protein. Conclusion c-jun participates in the toxicity process of brain injury by mercury polluted rice, the expression of c- jun mRNA in brain, and c-jun protein in rat cortex and hippocampus can predict neurotoxicity of mercury polluted rice. People should be advised to be cautious in eating any kind of Hg-polluted foods. To reveal the relationship between c-jun induction and apoptosis, further examinations are required.
文摘Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate were evaluated through different kinetics studies. Since chlorine was an electron withdrawing atom, the substitution of chlorine on the aromatic ring decreased the oxidation rate constant by σ-electron withdrawing conductive effect. The substitution of chlorine at ortho or para position on the aromatic ring increased the oxidation rate constant by π-electron donating conjugative effect, and the conjugative effect could counteract the negative impact of the conductive effect to some extent. On the other hand, the substitution of chlorine at ortho position on the aromatic ring decreased the oxidation rate constant by steric hindrance effect. The oxidation rate constants of phenol and chlorinated phenols studied decreased as follow order: 4-chlorophenol>2,4-dichlorophenol>phenol>2,6-dichlorophenol.
文摘The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD Cr and NH + 4-N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, COD Cr and NH + 4-N was 79.1%, 63.9% and 96.4% respectively under the influent COD Cr and NH + 4-N of 122.1 mgCOD Cr /L and 14.84 mgNH + 4-N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3∶1.
文摘The neurotransmitter level changes of ducks exposed 8-month in a mercury-polluted site(Wanshan, China) and a reference site(Shanghai, China) were examined. Chemical analyses showed both higher mercury and selenium concentrations in the organ of Wanshan ducks. An increased content of acetylcholine(ACh) in brain and blood and a decreased activity of acetylcholinesterase(AChE) in blood were observed. Moreover, there was an increasing trend for nitric oxide synthase(NOS) activity and nitric oxide(NO) production in duck brain, but a reduction of NOS activity in duck serum. The possible explanations were due to the interactive effect of selenium accumulation and the sublethal exposure level of mercury in Wanshan area. The present study showed that AChE and NOS were sensitive to mercury contamination of real circumstance, suggesting that these two indexes have the potential to be biomarkers in assessment of health effects by mercury contamination.
基金The National Basic Research Program(973) of China(No. JK00020)
文摘In the presence of inhibitors, the macroscopical oxidation kinetics of calcium sulfite, the main byproduct in wet limestone scrubbing, was studied for the first time by adding different inhibitors and varying pH, concentration of calcium sulfite, oxygen partial pressure, concentration of inhibitors and temperature. The mathematical model about the general oxidation reaction was established, which was controlled by three steps involving dissolution of calcium sulfite, mass transfer of oxygen and chemical reaction in the solution. It was concluded that the general reaction was controlled by mass transfer of oxygen under uncatalyzed conditions, while it was controlled by dissolution of calcium sulfite after adding three kinds of inhibitors. Thus, the theory was provided for investigating the mechanism and oxidation kinetics of sulfite. The beneficial references were also supplied for design of oxidation technics in the wet limestone scrubbing.
基金Chinese Jiangsu Province Education Committee Program (G0109199)Chinese Natural Science Foundation (50176051).
文摘The effect of additives (anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant alkyl polysaccharide glycoside (APG), and liquid hydrocarbon cyclopentane (CP)) on hydrate induction time and formation rate, and storage capacity was studied in this work. Micelle surfactant solutions were found to reduce hydrate induction time, increase methane hydrate formation rate and improve methane storage capacity in hydrates. In the presence of surfactant, hydrate could form quickly in a quiescent system and the energy costs of hydrate formation were reduced. The critical micelle concentrations of SDS and APG water solutions were found to be 300×10-6 and 500×10-6 for methane hydrate formation system respectively. The effect of anionic surfactant (SDS) on methane storage in hydrates is more pronounced compared to a nonionic surfactant (APG). CP also reduced hydrate induction time and improved hydrate formation rate, but could not improve methane storage in hydrates.
基金Project supported by the Foundation of Scientific and Technological from the Ministry of Education (No. 03071), of Natural Science Foundation of Jiangxi Province (No. 0320013) of the Youth Foundation of Nanchang University.
文摘The deactivation kinetics of Pd(PPh3)2Cl2 in the monocarbonylation of benzyl chloride to synthesize phenylacetic acid is studied in this paper. Solid 1-(2-pyridylazo)-2-naphthol (PAN) is used as the colouring agent, and the concentration of Pd(PPh3)2Cl2 in the system is measured through absorptiometry. The result shows that the optimum condition of the chromogenic reaction between Pd2+ and PAN is: 0.5 ml of 0.04% PAN added to 10 ml of Pd2+ solution (1.0×10-6-2.0×10-5 mol/L), and heated in a constant temperature water bath at 40℃ for about 30 min, with pH of the solution being about 3.0. The molar coefficient of absorption is 1.384×104 L/(mol·cm); the orders of the hydrolytic reaction to the concentration of Pd(PPh3)2Cl2, PPh3, phenylacetic acid and NaOH are 0.5, minus 0.8, 2 and 1.2, respectively. The activation energy (E) of the hydrolytic reaction is 75.59 kJ/mol, and the pre-exponential factor is 1.68×1012.
文摘A strain saccharomycete STSM-1 with high flocculanting activity was isolated from activated sludge with conventional methods. The high production rate and the low cost STSM-1 medium was obtained by selecting different kinds of media, carbon source, nitrogen source and inorganic salt ion. The best flocculant-producing conditions were found by changing medium initial pH, culture temperature and ventilation flow. The best flocculating effect was obtained by changing positive ion types, density and concentration of flocculant.
文摘The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO 2. The ASBR was operated at four chemical oxygen demand(COD) loading rates, 2.8, 5.1, 6.2 and 8.4 g/(L·d) respectively. The COD loading rate was increased with the TS concentration and HRT changing. At maximum COD loading rate of 8.4 g/(L·d), the COD, total solid(TS) removal rate and methane gas yield were 69%, 68% and 2.5 L/(L·d) respectively. The operation of the reactor with gas-phased absorb of CO 2 was stable in spite of the low pH(2.6—3.9) and high concentration of TS(142 g/L) of input mixture. The output volatile fatty acid(VFA) concentration was between 2.7—4.7 g/L and had no inhibition on the methanogenic microorganism. The reactor without gas-phased absorb of CO 2 became acidified when the total COD loading rate was increased to 5.1 g/(L·d). Stoichiometry of the methanogenesis for kitchen wastes showed a considerable amount of alkaline will be required to keep pH in the appropriate range for the methanogenic microorganism based on theoretical calculation. Gas-phased absorb of CO 2 effectively reduced the alkaline consumption, hence avoided excessive cation into the reactor.
基金Supported by the National Natural Science Foundation of China
文摘The paper deals with the degradation of the organic compounds in the coke plant wastewater by the combined process of ultrasonic irradiation and activated sludge. The influence factors of the ultrasonic degradation effect such as air atmosphere, initial concentration, ultrasonic power density and the category and consumption of catalyst were investigated. A water quality model was used to explain the degradation of different kinds of organic compounds in the coke plant wastewater by ultrasonic irradiation. After the wastewater was treated by the combined process of ultrasonic irradiation and activated sludge, the COD degradation efficiency was 95.74%, which is 63.49% higher than that by the process of activated sludge alone.
基金Under the auspices of the keyproject of Shandong Provincial Environmental Protection Bureau (No. 2003447)
文摘Public participation has been one of important problems in the strategic environmental assessment (SEA). In this paper, the origin and the present research-conditions of public participation in SEA were analyzed. And the necessity of public participation was illuminated from following three aspects: 1) the public participation in China′s SEA is a key method of gaining the public support; 2) the public participation is one important source of gaining information; 3) the public participation is a good way to overcome the obstruction in the traditional mechanism of making strategy decision. Effective public participation should be involved in the whole process of SEA, and the public participators should include the public representatives of the groups affected by environmental change, the specialists in SEA and relevant fields, persons who are interested in the strategy and media, and so on. Various methods of public participation in SEA, including the methods of obtaining information and information feedback or consultation, were discussed. Further, the function, the advantages and the disadvantages of each method were discussed in detail, too.
