酸改性剩余污泥对亚甲基蓝吸附性能的研究

用磷酸对剩余污泥进行改性,研究改性后的污泥对亚甲基蓝的吸附效果.结果表明,pH值增大对改性污泥的吸附有促进作用.在碱性条件下,改性污泥的吸附效果要优于未改性的污泥.温度升高,平衡时间缩短;温度在25,35,45℃时,平衡时间分别为6.5,4.5,3.5h,去除率分别为97.2%,92.2%和90.5%.改性剩余污泥对亚甲基蓝的吸附符合Freundlich等温吸附方程,该吸附是一个自发的放热过程.

高岭土在盐湖卤水提锂中的应用

煅烧酸浸法对高岭土进行处理,得酸改高岭土和铝浸出液。以酸改高岭土对当雄错盐湖卤水中的锂进行吸附,铝浸出液沉淀吸附后卤水中剩余的锂,再以铝浸出液作吸附后酸改高岭土的解吸剂,并对解吸液再次进行沉淀提锂,从而确定高岭土在盐湖卤水提锂中的最佳工艺。结果表明:高岭土煅烧酸浸后Al_2O_3溶出率高,浸出液中的AlCl_3浓度可达0.97mol/L,而所得酸改高岭土孔洞丰富,比表面积较大;以酸改高岭土对锂浓度为320mg/L的卤水进行吸附,发现在酸改高岭土用量为4.0g、体系pH为12、吸附温度为40℃、吸附时间为150min时,有最大锂吸附量,为4.51mg/g;此时,吸附后卤水中锂的浓度为230mg/L,再以铝浸出液沉淀该卤水中的锂,当Al/Li摩尔比为3.5、Na/Al摩尔比为2.7、反应温度为55℃、反应时间为1h时,锂的最大沉淀率为45.3%;将铝浸出液用水稀释1倍,取35m L对4.0g吸附后的酸改高岭土进行解吸,55℃反应20min,Li+解吸率达93.12%,Li+浓度为480mg/L,再次沉淀提锂时,锂沉淀率为84.51%。

粉煤灰负载钒氧化物低温SCR催化剂脱硝性能研究

目前,我国电厂普遍采用SCR法高含尘工艺对烟气中的NOx进行脱硝,催化剂存在严重堵塞、中毒等问题,SCR法低含尘工艺越来越引起重视。为了制备SCR法低含尘工艺中的低温SCR脱硝催化剂,本文将钒氧化物负载在粉煤灰和膨润土混合制成的复合材料载体上,制成V2O5/FA-BT催化剂,同时分别用全自动比表面及孔隙度分析仪(Micromeritics Tristar 3 000)和扫描电子显微电镜(SEM)对催化剂的比表面积和表面形貌进行表征。结果表明:不同V2O5负载量的V2O5/FA-BT催化剂在低温下有很好的脱硝效果,其中以V2O5负载量(质量分数)为11%的V2O5/FA-BT脱硝效果最好,当反应温度为130℃时,脱硝率达到89%;对催化剂进行酸改,CH3COOH酸改的催化剂比表面积较大且脱硝效果最好。

Influencing factors analysis of hard limestone reformation and strength weakening under acidic effect

Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.

Preparation of UV-visible light responsive photocatalyst from titania-bearing blast furnace slag modified with(NH_4)_2SO_4

Sulfate-modified titanium dioxide-bearing blast furnace slag（STBBFS） photocatalysts were prepared by the high energy ball milling method with（NH4）2SO4 and titanium dioxide-bearing blast furnace slag（TBBFS） as raw materials.X-ray photoelectron spectroscopy（XPS）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,thermogravimetric analysis（TGA）,UV-visible diffuse reflectance absorption spectra（UV-Vis）,adsorption experiment and photocatalytic degradation measurement were conducted to characterize the structure,surface status,light absorption capacity,adsorption capacity and photocatalytic activity of the obtained photocatalysts.The adsorption equilibrium was described by the Langmuir isotherm model with a maximum adsorption capacity of 8.25 mg/g of Cr（VI） ions onto the STBBFS photocatalysts.As a result,sulfation of TBBFS improved the photocatalytic activities of STBBFSx photocatalysts.At a low calcination temperature,the photocatalytic activity of STBBFS300 photocatalyst was markedly higher compared with TBBFSx prepared at high calcination temperature,indicating that the photocatalytic activity of STBBFSx photocatalyst was determined by the balanced result between adsorption capacity and perovskite content.

基于农田中试试验的重金属污染原位钝化修复效果研究与评估

当前,受城市及工业化迅猛发展影响,我国耕地数量与质量持续下降,重金属污染问题尤为突出。原位固化技术作为一种绿色低碳技术,可有效限制重金属的可生物利用性,从而提高我国耕地数量与安全利用率。本研究以田间试验为基础,以小麦籽粒中重金属含量为评价标准,对酸改凹凸棒石、凹凸棒石、酸改Fixall药剂和Fixall药剂的剂量及应用条件进行探究。研究结果表明,对于铅、镉和砷,酸改凹凸棒石和酸改Fixall药剂对农田重金属的钝化效果更优,酸改凹凸棒石的最佳添加质量比分别为3%、3%和7%,与对照组相比,小麦籽粒中对应含量下降分别为48.21%、49.81%和25.40%。酸改Fixall药剂对农田重金属的钝化效果最佳添加质量比相同,均为3%,与对照组相比,小麦籽粒中对应含量下降分别为59.76%、46.63%和24.60%。其中,经添加比为3%的酸改Fixall药剂处理后,小麦籽粒中铅元素含量达到《食品安全国家标准食品中污染物限量》(GB 2762-2017)规定的要求,其他重金属含量得到显著降低,对提高我国农田数量可利用性及使用安全率具有广泛的应用前景。

Adsorption of Cr(Ⅵ) in Water with Phosphoric Acid Modified and Ordinary Walnut Shells

A comparison between the effects of ordinary walnut shell and phosphoric acid modified walnut shell on adsorption of Cr（Ⅵ） was carried out. The experimental results showed that owing to larger surface void of modified walnut shell its adsorption of Cr（Ⅵ） was better. When the temperature was 35 ℃, adsorbent particle size was 1.0-1.6 mm, shaker shock rate was 200 r/min, and dosage of walnut shell was 0.80 g, the Cr（Ⅵ） removal rate reached 99.4%. The fitting of adsorption isotherm and kinetics model showed that, Langmuir isotherm model could reflect the adsorption process of modified walnut shell; and both the adsorption processes of ordinary and modified walnut shells accorded with the pseudo-second-order kinetic equations.

Molecular Mechanisms of Cyclic Nucleotide-Gated Ion Channel Gating

Cyclic nucleotide-gated ion channels （CNGs） are distributed most widely in the neuronal cell. Great progress has been made in molecular mechanisms of CNG channel gating in the recent years. Results of many experiments have indicated that the stoichiometry and assembly of CNG channels affect their property and gating. Experiments of CNG mutants and analyses of cys- teine accessibilities show that cyclic nucleotide-binding domains （CNBD） bind cyclic nucleotides and subsequently conformational changes occurred followed by the concerted or cooperative conformational change of all four subunits during CNG gating. In order to provide theoretical assistances for further investigation on CNG channels, especially regarding the disease pathogenesis of ion channels, this paper reviews the latest progress on mechanisms of CNG channels, functions of subunits, processes of subunit assembly, and conformational changes of subunit regions during gating.

Remediation of in-situ Leach Mining Contaminated Soil by Amendment-plant Synergism

This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3：50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10：50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.

Nitrate-group-grafting-induced assembly of rutile TiO2 nanobundles for enhanced photocatalytic hydrogen evolution

In this study,an acid-induced assembly strategy for a rutile TiO2 photocatalyst was proposed on the basis of the treatment of lamellar protonated titanate with a concentrated HNO3 solution.Nitrate groups were successfully grafted onto a TiO2 surface and induced the assembly of rutile TiO2 nanorods into uniform spindle-like nanobundles.The resulting TiO2 product achieved a photocatalytic hydrogen evolution rate of 402.4μmol h^?1,which is 3.1 times higher than that of Degussa P25-TiO2.It was demonstrated that nitrate group grafting caused the rutile TiO2 surface to become negatively charged,which is favorable for trapping positive protons and improving charge carrier separation,thereby enhancing photocatalytic hydrogen production.Additionally,surface charges were crucial to structural stability based on electrostatic repulsion.This study not only developed a facile surface modification strategy for fabricating efficient H2 production photocatalysts but also identified an influence mechanism of inorganic acids different from that reported in the literature.

Preparation,characterization and photocatalytic activity of sulfuric acid-modified titanium-bearing blast furnace slag

The feasibility of reducing Cr(VI)from the aqueous solution by sulfuric acid-modified titanium-bearing blast furnace slag(SATBBFS)as a photocatalyst was investigated.The photocatalysts were examined by X-ray diffraction(XRD),UV-vis diffuse reflectance spectra,thermogravimetric analysis(TG)and Fourier transform infrared spectroscopy(FTIR).The photocatalytic activities of the different catalysts were evaluated by the photocatalytic reduction of Cr(VI)under UV-vis light irradiation.The results show that the photocatalytic activities of SATBBFS catalysts are strongly dependent on CaTiO3-to-TiO2 mass ratio,adsorption capacity and surface acidity,and SATBBFS calcined at 400°C shows a higher photocatalytic activity compared with other catalysts.

Effect of Low-Molecular-Weight Organic Acids on Cl-Adsorption by Variable Charge Soils

Low-molecular-weight (LMW) organic acids exist widely in soils and have beenimplicated in many soil processes. The objective of the present paper was to evaluate effect of twoLMW organic acids, citric acid and oxalic acid, on Cl^-adsorption by three variable charge soils, alatosol, a lateritic red soil and a red soil, using a batch method. The results showed that thepresence of citric acid and oxalic acid led to a decrease in Cl^- adsorption with larger decreasesfor citric acid. Among the different soils Cl^- adsorption in the lateritic red soil and the redsoil was more affected by both the LMW organic acids than that in the latosol.

Transformation of Flue-Gas-Desulfurization Gypsum to α-Hemihydrated Gypsum in Salt Solution at Atmospheric Pressure

Direct phase transformation of flue gas desulfurization gypsum in hot salt solution at atmospheric pres-sure was investigated.The effects of temperature,salt species,salt concentration,solids content,pH and modifier were examined.The crystals obtained under different conditions and solubility of calcium sulfate in contact with solid gypsum were also determined.α-Calcium sulfate hemihydrate crystals of stubby columnar shape and regular pentahedral sides were obtained under the following conditions：salt concentration 20%-30%,operation tempera-ture 95-100 °C,solids mass content in the slurry 10%-30% and neutral pH.Thermodynamic analysis revealed that phase transformation of calcium sulfate dihydrate to α-calcium sulfate hemihydrate occurs because of the difference in solubilities between the two solid gypsum phases in this system.

NO adsorption and temperature programmed desorption on K_2CO_3 modified activated carbons

Fuel cell stacks as the automotive power source can be severely poisoned by a trace amount of NOx in atmosphere,which makes it necessary to provide clean air for fuel cell vehicles.In this work,activating commercial activated carbons with K2CO3 for the large enhancement of NO capture was studied.K2CO3 modified activated carbons(K2CO3 ACs)were prepared by impregnating activate carbons in K2CO3 solution under ultrasound treatment,followed by temperature programmed baking at 800 oC.The dynamic NO flow tests on K2CO3 ACs at room temperature indicated that NO adsorption capacity reached the maximum(96 mg/g)when K2CO3 loading was 19.5 wt%,which corresponded to a specific surface area of 1196.1 m2/g and total pore volume of 0.70 cm3/g.The ten-fold enhancement of NO adsorption on K2CO3 ACs compared to the unimpregnated activated carbon was mainly attributed to the formation of potassium nitrite,which was confirmed by FTIR and temperature programmed desorption measurements.Regeneration tests of NO adsorption on the optimum sample revealed that 76%of the NO adsorption capacity could be remained after the fourth cycle.

Deletion of 93 bp Far-upstream Fragment of Rice Cytosolic Fructose- 1, 6-Bisphosphatase Promoter Completely Alter Its Expression Pattern

The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements responsible for the regulation of mesophyll_specific expression, the 5′ flanking regions of -1 195 bp, -1 102 bp, -768 bp, and -644 bp upstream of the translation initiation ATG codon were fused to the reporter gene encoding β_glucuronidase (GUS) and transferred to rice via particle bombardment. Analysis of the 5′ promoter deletions identified that a 93 bp fragment between -1 195 bp and -1 102 bp is essential for directing mesophyll specific expression. High constitutive expression of GUS reporter gene was found in the -768 deletion lines and another two deletion series. These results indicate the great potential utility of the promoter in rice biotechnology.

Modification of nanometer calcium carbonate for water-borne architectural coatings

A kind of modifier was synthesized to modify the surface of nanometer calcium carbonate （abbreviated as nano-CaCO3）, which is used in architectural coatings. The modification technology of the nano-CaCO3 was studied through orthogonal experimental methods. The factors studied were rotation speed, modifier dosage, emulsification temperature, emulsification time and heat aging time after emulsification. Optimized conditions for modification of the surface were： rotation speed 16000 r/min; modifier dosage 3%; emulsification temperature 75 ℃; emulsification time 60 min and aging time 40 min. The modified nano-CaCO3 was also studied by size-distribution measurements, transmission electron microscopy, infrared spectroscopy and thermal analysis. The results show that the size distribution of the modified nano-CaCO3 is uniform and that there are chemi-sorption and physi-sorption between the nano-CaCO3 and the modifier. Compared to traditional architectural coatings without nano-CaCO3, the nanometer composite coatings are obviously improved in respect to dirt resistance, scrub resistance, thixotropy, water resistance, alkalinity resistance and aging resistance.

Removal of diclofenac from aqueous solution with multi-walled carbon nanotubes modified by nitric acid

Modified multi-walled carbon nanotubes(MWCNTs) were used as adsorbents for removal of diclofenac. The reaction conditions were examined. Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models were applied to determine appropriate equilibrium expression. The results show that the experimental data fit the Freundlich equation well. Thermodynamic parameters show that the adsorption process is spontaneous and exothermic. The kinetic study indicates that the adsorption of diclofenac can be well described with the pseudo-second-order kinetic model and the process is controlled by multiple steps.

Enhancing electrochemical performance of SnO_(2) anode with humic acid modification

Humic acid(HA)was studied as a modifier in the SnO_(2) anode preparation for the electrochemical performance improvement.Scanning electron microscopy,180°peel test,and nanoindentation experiment were used to examine the influence of the HA on electrode.The results showed that the addition of HA could improve the dispersion uniformity of all particles.The components were tightened,increasing the difficulty of peeling off the film from the current collector.The deformation resistance of the electrode was greatly enhanced by the HA modification.The electrochemical test results showed that the anode from the normal micron-sized SnO_(2)particles with the HA modifier exhibited significant progress in electrochemical performance compared with those without HA.The reversible specific capacity of the SnO_(2) anode can be maintained as high as 733.4 mA·h/g at a current density of 100 mA/g after 50 cycles.Therefore,HA is a promising modifier for anode preparation of lithium-ion batteries.

Preparation, morphology and mechanical properties of acrylate-modified polyurethane/unsaturated polyester resin graft-IPNs

Acrylate modified polyurethane resin was first synthesized, and interpenetrated with unsaturated polyester resin to form IPNs and gradient IPNs which cured at room temperature. The polymerization process was traced by an IR spectroscopy technique and the simultaneous interpenetrating techniques were determined. The morphology of these IPNs were estimated by TMA and TEM methods. The results indicated that large amount of interpenetrating and entanglement make T g linked up effectively, and domains between two phases can be in nanometre ranges, which changed with composition ratios. The mechanical properties results showed that IPNs varied from elastomeric to plastic materials. It was noteworthy that, with the introduction of modified groups and the formation of graft construction in IPNs, the miscibility in the systems was improved a lot. These further led to the improved mechanical properties of IPNs with elastomer reinforced and plasticizer toughened as well. The reinforced miscibility between the networks can apparently change mechanical property especially for the gradient ones when the materials are elongated.

SWELLING AND WETTABILITY OF LIGHT-CURED METHACRYLATE-BASED DENTAL RESINS PREPARED FROM CHOLIC ACID

2＇-methacryloxy-3α, 7α, I2α- trimethacryloyl cholic acid ethyl ester （CAGE4MA） has been prepared from cholic acid. Photo-polymeric resins were prepared from CAGE4MA. 2,2-bis[4-（2-hydroxy-3-methacrylyloxypropoxy）phenyllpropane （bis-GMA） was used for comparison, triethyleneglycol dimethacrylate （TEGDMA） was used as diluent. The polymerization was initiated by camphoroquinone （CQ）/N, N-dimethylaminoethyl methacrylate （DMAEMA） system. The conversion of CAGE4MA was 39% when the reaction time is 60s, which is lower than bis-GMA and TEGDMA. The swelling value of CAGE4MA resin was 0.41% in distilled water, which is much lower than those of bis-GMA resin （2.04%） and TEGDMA resin （4.77%） under the same conditions. Copolymers from CAGE4MA and TEGDMA have been prepared. With the increase of TEGDMA in mixture, the degree of conversion of CA GE4MA and swelling value increased. The swelling values of photocured resins in 0.1mol/L HCl were also measured.