均粒石英砂滤料过滤效果的生产性试验与应用

目的将快滤池的传统滤层改造为均粒石英砂滤层,为的是改善滤池的工作性能,提高产水量.方法采用均粒石英砂滤料,粗粒石英砂滤料及常规石英砂滤料进行生产对比试验,研究粒径与过滤周期、滤速、反冲洗强度、反冲洗时间的关系.结果研究表明,均粒滤料与非均粒滤料相比,滤速提高15%以上,过滤周期提高13h以上,反冲洗强度和反冲洗时间变化不大.结论均粒滤料的过滤性能优于非均粒滤料,将常规石英砂滤料更换为平均粒径相同的均粒石英砂滤料,能够延长过滤周期,提高产水量,经济效益明显.     

沸石-石英砂生物滤池处理微污染水中试研究

通过中试考察了沸石-石英砂双层滤料生物滤池处理微污染水的运行效能,探讨了生物滤池处理此类水体的可行性.结果表明,生物滤池可以有效地提高出水水质,对浊度、CODMn、波长为254 mm的紫外吸光度A254、NH3-N和NO-2-N的去除率分别达到93.5%、38%、40%、95%及100%,而且工作区间主要集中在滤层上部30 cm内;反冲洗对滤料表面附着的微生物膜影响很小,生物膜在反冲洗后1~2 h内能恢复到反冲洗前的水平.因此,对于该污染水源水,采用沸石-石英砂生物滤池替代原有普通滤池.     

填料对接触氧化滤柱去除地下水中铁锰的研究

研究了以河砂和锰砂为填料时，接触氧化滤柱对铁锰的去除效果以及反冲洗对去除效果的影响. 结果表明，在滤速为8.3m/h、进水pH值为6.8、溶解氧为1.7mg/L的条件下，河砂填料和锰砂填料滤柱对铁的去除效果分别需要9d和2d即可稳定，出水铁浓度均在0.3mg/L以下；河砂填料和锰砂填料滤柱对锰的去除效果分别需要48d和16d方可稳定，出水锰浓度均在0.1mg/L以下. 反冲洗之后，河砂滤柱对铁和锰的去除能力需要40min和80min才能完全恢复；锰砂滤柱对铁、锰的去除能力需要20min和40min才能完全恢复. 扫描电境对滤膜形态分析表明，成熟的除铁锰滤膜表面呈絮状，反冲洗之后滤料表面仍然附着有絮状滤膜，该絮状滤膜是反冲洗后除铁锰效果能够快速恢复的基础. 实际工程中可以采取价格便宜的河砂取代锰砂，由此可以节省填料投资的90%.     

填料对接触氧化滤柱去除地下水中铁锰的研究

研究了以河砂和锰砂为填料时，接触氧化滤柱对铁锰的去除效果以及反冲洗对去除效果的影响．结果表明，在滤速为8、3m／h、进水pH值为6．8、溶解氧为1．7mg／L的条件下，河砂填料和锰砂填料滤柱对铁的去除效果分别需要9d和2d即可稳定，出水铁浓度均在0．3mg／L以下；河砂填料和锰砂填料滤柱对锰的去除效果分别需要48d和16d方可稳定，出水锰浓度均在0．1mg／L以下．反冲洗之后，河砂滤柱对铁和锰的去除能力需要40min和80min才能完全恢复：锰砂滤柱对铁、锰的去除能力需要20min和40min才能完全恢复．扫描电境对滤膜形态分析表明，成熟的除铁锰滤膜表面呈絮状，反冲洗之后滤料表面仍然附着有絮状滤膜，该絮状滤膜是反冲洗后除铁锰效果能够快速恢复的基础．实际工程中可以采取价格便宜的河砂取代锰砂，由此可以节省填料投资的90％．     

湿法磷酸脱氟研究

本文用二次回归正交组合设计法,对用硫酸钠从湿法磷酸中脱氟生成氟硅酸钠过程中,MgO、Al_2O_3和Fe_1O_3等杂质及Na_2O对脱氟率的影响进行了研究.通过方差分析,得出数学模型.用文献数据和粗磷酸脱氟的实测数据对此模型进行了检验,脱氟率的计算值与实测值相对误差小于10％。用放置较长时间的湿法磷酸脱氟,可获得结晶粗大、便于过滤、洗涤的滤饼。用5％Na_2SO_4溶液充分洗涤后,所得氟硅酸钠符合二级品要求.     

改性陶瓷滤料处理武钢含油废水的应用研究

利用武钢水站中的废弃污泥制作陶瓷滤料,并进行表面改性,然后将其投入到对武钢热轧废水处理的应用研究中。在与传统滤料石英砂进行对比的实验中发现,改性滤料在对悬浮物的去除率、对油的去除率和延长过滤周期等方面均大大优于传统石英砂滤料。分析了改性陶瓷滤料的除油机理,通过实验确定了改性陶瓷滤料在对含油废水处理时运行的最佳条件,在滤料粒径为0.8～1.0mm,滤速为8～10m/h,pH为6.8左右,滤层厚度为800mm时拥有良好的处理效果,且运行成本较低。     

曝气生物滤柱处理生活污水工艺研究

为实现生活污水设备的快速一体化设计,结合自行研制的曝气生物滤柱,探究曝气生物滤柱运行方式和运行参数,并与石英砂滤柱的处理效果进行了对比.实验结果表明:反冲洗的频次对挂膜有显著影响;冲洗强度、时间与滤层的生物量密切相关,当水力负荷为3.0m3/m2h、采用三段式联合反冲洗、过滤周期控制为48h时,曝气生物滤柱对悬浮物的处理效果最佳,能够促进微生物在滤柱内重新均匀分布,促使滤柱新旧微生物群落的更替.     

改性活性氧化铝吸附去除水中痕量磷的性能

为了获得更为高效的去除水中痕量磷的方法,通过静态吸附试验考察了经Al_2(SO_4)_3或Na_2SO_4改性的活性氧化铝(γ-Al_2O_3)吸附除磷性能,观察了吸附剂投量、pH值及水温变化对PO_4~3-P去除效果的影响及改性前后的γ-Al_2O_3对模拟水样中不同形态磷的去除效果.结果表明:γ-Al_2O_3经Al_2(SO_4)_3或Na_2SO_4改性后对PO_4~3-P的去除效果比改性前有显著提高,对PO_4~(3-)-P的去除率分别提高了18.53%和14.34%;改性γ-Al_2O_3对PO_4~(3-)-P的去除率在-定的投量范围内随投量的增加明显提高;改性γ-Al_2O_3对PO_4~(3-)-P的吸附作用以物理吸附为主,随着温度和pH值的升高,除磷效果均呈下降趋势;经Al_2(SO_4)_3改性的γ-Al_2O_3表现出更好的除磷效果和较强的水质适应性;水中浊质对吸附除磷效果影响较大,因此γ-Al_2O_3更适合滤后水的深度除磷.     

三聚磷酸钠对镁合金阳极氧化膜性能的影响

为进一步提高镁合金阳极氧化膜的耐蚀性,在NaOH+Na_2SiO_3+Na_2CO_3+C_(10) H_(16) N_2O_8基础电解液中添加三聚磷酸钠,对Mg_(97)Y_2Zn_1-1.5Al镁合金进行阳极氧化,研究三聚磷酸钠对镁合金阳极氧化过程、表面形貌及耐蚀性的影响.探讨三聚磷酸钠在镁合金阳极氧化中的作用机制.结果表明:三聚磷酸钠参与了阳极氧化过程,降低了击穿电压,平缓了最终电压的波动,对阳极氧化膜形貌以及耐蚀性能均有明显影响.当三聚磷酸钠浓度为0.12 mol/L时,阳极氧化膜孔隙细致均匀,膜层裂纹较少,耐蚀性能最佳.     

过滤工艺中颤蚓的迁移分布规律

中试条件下研究了颤蚓在过滤工艺中的迁移分布规律,并考察了滤速和过滤周期对颤蚓迁移分布的影响,以及反冲洗后滤池中颤蚓的分布情况。结果表明：颤蚓在滤池中沿滤床深度方向的迁移与颤蚓体长和滤料粒径有关,颤蚓体长越小、滤料粒径越大,则迁移幅度越大;滤速是颤蚓迁移的主要动力,滤速的提高会引起下层滤床中颤蚓数量的增加,颤蚓泄露风险加大;过滤周期的延长将促进颤蚓的迁移,适当缩短过滤周期有利于水厂颤蚓泄露风险控制;反冲洗可以实现颤蚓从净水工艺中的彻底去除,反冲洗强度越大,颤蚓的去除效果越好。为有效控制颤蚓泄露风险,滤池滤速和过滤周期宜分别控制在9．4m／h和12h以下,反冲洗强度则控制在25L／s·m^2左右,此时颤蚓去除率为97．7％。     

Corrosion resistance of cerium conversion film electrodeposited on Mg-Gd-Y-Zr magnesium alloy

The cerium conversion film was applied to improving the corrosion resistance of Mg-Gd-Y-Zr magnesium alloy. The film was electrodeposited on the surface of the Mg-RE alloy in cerium nitrate solution. The compositions and morphologies were analyzed by X-ray diffraction(XRD), scanning election microscopy (SEM). The corrosion behaviors of the film were investigated electrochemical impedance spectroscopy (EIS), potentiodynamic polarization tests and immersion tests. The results show that the optimum parameters for electrochemical deposition are as follows: pH 10.0, time 30 min, 50 mmol/L Na₂CO₃ and temperature 25 °C by the designed experiments according to the orthogonal table L(9, 3⁴). The corrosion protection efficiency is dependent on the deposition parameters. The cerium conversion film shows better corrosion protection behavior than chromate conversion film on Mg-Gd-Y-Zr magnesium alloy. Foundation item: Project (5133001E) supported by the Major State Basic Research and Development Program of China     

Molten salts/ceramic-foam matrix composites by melt infiltration method as energy storage material

A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding SiC ceramic foam as matrix and Na₂SO₄ as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs between Na₂SO₄ and SiC matrix. Na₂SO₄ has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage density and high thermal conductivity, it is suit for energy storage under high temperature. Funded by the “863” Hi-Tech Research and Development Program of China (2008AA05Z418)     

BaZr0.9Y0.1O2.95/Na2SO4 composite with enhanced protonic conductivity

Heterogeneous composite BaZr_0.1Y_0.9O_2.95/Na₂SO₄ was designed and fabricated with Y-doped BaZrO₃ as matrix and Na₂SO₄ as dispersant by conventional powder processing to improve the total conductivity of barium zirconate. The electrical conduction of the composite was studied by electrical and electrochemical methods. Microstructure of the heterogeneous composite was examined by SEM. The experimewtal results show that the protonic conductivity of Y-doped BaZrO₃ is greatly improved upon incorporating Na₂SO₄ in the material. Microstructure observation indicates that a multiphase structure with Na₂SO₄ disperses at the grain boundaries of BaZr_0.1Y_0.9O_2.95. Electromotive force (EMF) measurements under fuel cell conditions reveal that the total ionic transport number of the composite is more than 0.9 at 750 °C. Funded by the National natural Science Foundation of China(No. 50872090)     

Optimization of efficient stable reagent of alkaline thiourea solution for gold leaching

1　INTRODUCTIONThiourea ,asanontoxic goldleachingreagentsubstitutingcyanide ,hasattractedtheinterestofmanyresearchersallovertheworldsincethedissolu tionofgoldinthioureasolutionwasfirstreportedin194 1,andaseriesofstudiesonthetheoryandtech nologyforleachinggoldbythioureahavebeencon ducted[1 3] .Mostreportson golddissolutioninthioureasolutionwereconcernedwithacidicmedia .Itwasdifficultforgoldtodissolveinalkalinesolutionbecauseofthepassivationofelementsulfurproducedbytheirreversibledecompositi…     

Effect of corrosive solutions on C-S-H microstructure in portland cement paste with fly ash

By means of ²⁹Si and ²⁷Al magic angle spinning nuclear magnetic resonance (MAS NMR) combined with deconvolution technique, X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as energy dispersive X-ray system(EDX), the effect of 5 wt% corrosive solutions (viz. 5 wt% Na₂SO₄, MgSO₄, Na2SO4+NaCl and Na₂SO₄+NaCl+Na₂CO₃) on C-S-H microstructure in Portland cement containing 30 wt% fly ash was investigated.The results show that, in MgSO₄ solution, Mg²⁺ promotes the decalcification of C-S-H by SO ₄ ^2- ,increasing silicate tetrahedra polymerization and mean chain length (MCL) of C-S-H. However, the substituting degree of Al³⁺ for Si⁴⁺ (Al[4]/Si) in the paste does not change evidently. Effect of Na²SO⁴ solution on C-S-H is not significantly influenced by NaCl solution, while the MCL and Al[4]/Si of C-S-H in fly ashcement paste slightly change. However, the decalcification of C-S-H by SO ₄ ^2- and CO ₃ ^2- attack, as well as the activation of fly ash by SO ₄ ^2- attack will increase the MCL and Al[4]/Si, which are both higher than that under Na₂SO₄ corrosion, MgSO₄ or Na₂SO₄ +NaCl coordination corrosion.     

Deterioration mechanism of sulfate attack on concrete under freeze-thaw cycles

The experiments of concrete attacked by sulfate solution under freeze-thaw cycles were investigated. The sulfate solution includes two types of 5% Na2SO4 and 5% MgSO4. Through the experiment, microstructural analyses such as SEM, XRD and TGA measurements were performed on the selected samples after freeze-thaw cycles. The corrosion products of the concrete were distinguished and quantitatively compared by the thermal analysis. Besides, the damage mechanism considering the dynamic modulus of elastically of concrete under the coupling effect was also investigated. The experimental results show that, under the action of freeze-thaw cycles and sulfate attack, the main attack products in concrete are ettringite and gypsum. The corrosion products exposed to MgSO4 solution are more than those to Na2SO4 solution. Furthermore, the content of gypsum in concrete is less than that of ettringite in test, and some of gypsum can be observed only after a certain corrosion extent. It is also shown that MgSO4 solution has a promoting effect to the damage of concrete under freeze-thaw cycles. Whereas for Na：SO4 solution, the damage of concrete has restrained before 300 freeze-thaw cycles, but the sulfate attack accelerates the deterioration process in its further test period.     

SO2-4对块体纳米晶铜阳极极化行为的影响

为了揭示SO₂^-4对块体纳米晶铜耐蚀性能的影响规律,利用电化学方法,结合X射线衍射、能谱分析、扫描电镜等表面分析技术,研究了惰性气体沉积原位温压法制备的块体纳米晶铜在不同质量分数（0.3%、1.3%、2.3%、3.3%和4.3%）Na₂SO₄溶液中的阳极极化行为.结果表明,随着SO₂^-4的增多,纳米晶铜的致钝电流密度增大,而致钝电位降低.在0.3%的Na₂SO₄溶液中加入1%的NaCl,纳米晶铜阳极极化行为发生明显变化,Cl^-在纳米晶铜表面形成难溶于水的CuCl保护钝化膜,纳米晶铜致钝电流密度降低,活化-钝化过渡区电流密度下降速率显著减小.     

Effects of CFB Ash on the Adsorption Mechanism of Polycarboxylate Superplasticiser

The effects of circulating fluid bed(CFB) ash on the adsorption performance of polycarboxylate superplasticiser and the mechanism of this influence on the dispersive property of the polycarboxylate superplasticiser were investigated by determing the cement paste fluidity, total organic carbon adsorption, infrared spectroscopic analyses and ζ potential test. The experimental results show that the addition of an inorganic salt into the mixture to change the content of SO_4~(2-)and Fe_2 O_3 can improve the adaptability between the CFB ash and polycarboxylate superplasticiser. Adsorption may occur between the polycarboxylate superplasiciser and Fe_2 O_3, SO_4~(2-)or other components in CFB ash, leading to a significant reduction in paste fluidity. As the content of Na_2 SO_4 in CFB ash reaches 3% or Fe_2 O_3 reaches 9%, the paste loses its liquidity. The organic carbon content in the liquor decreases with an increase in Na2_ SO_4 or Fe_2 O_3 content. Adding some Ba(NO_3)_2 and Na_2 S to the liquor can recover the organic carbon content to a certain extent, and the absolute value of ζ potential will increase. The addition of Ba(-NO_3)_2 or Na_2 S reduces the adsorption property of Na_2 SO_4 or Fe_2 O_3 in CFB ash on the polycarboxylate superplasticiser.     

Preparation of TiO2 Thin Film and Its Antibacterial Activity

TiO2 nanometer thin films with photocatalytic antibacterial activity were prepared by the sol-gel method on fused quartz and soda lime glass precoated with a SiO2 layer. The thin films were characterized by X-ray photoelectron spectroscopy ( XPS ), scanning electron microscopy (SEM), and X- ray diffraction ( XRD ). The results show that sodium and calcium diffusion into nascent TiO2 film is effectively retarded by the SiO2 layer precoated on the soda lime glass, The antibacterial activity of the films was determined. The crystalline of TiO2 nanometer thin film has important effects on the antibacterial activity of the film.     

Hydrothermal synthesis of WO<Subscript>3</Subscript> nanowires in the presence of guanidine sulfate and its photocatalytic activity

WO₃ nanowires were fabricated by a hydrothermal method, which proceeded at 170 °C for 48 h in a solution containing C₂H₁₀N₆H₂SO₄ as a dispersant and Na₂WO₄ as a starting material. The nanowires exhibit a well crystallized one-dimensional structure with 20 nm in diameter and several microns in length. The physicochemical properties of WO₃ were compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and UV-vis spectroscopy (UV-Vis). The photoactivity of the as-perpared WO₃ nanowires was evaluated through the photodegradation of methylene blue (MB) in aqueous solution. The experimental results demonstrate that addition of C₂H₁₀N₆H₂SO₄ salt in the WO₃ nanowires synthesis process can enhance its photocatalytic activity obviously.