Experimental and computational chemical studies on the cationic furanylnicotinamidines as novel corrosion inhibitors in aqueous solutions

The corrosion inhibition action of three newly synthesized furanylnicotinamidine derivatives namely: 6-[5-{4(dimethylamino)phenyl}furan-2-yl]nicotinamidine(MA-1256), 6-[5-(4-chlorophenyl)furan-2-yl]nicotinamidine(MA-1266), and 6-[5-{4-(dimethylamino)phenyl}furan-2-yl]nicotinonitrile(MA-1250) on carbon steel(C-steel) was investigated in 1.0 mol·L~(-1) HCl solution by weight loss(WL), potentiodynamic polarization(PP), electrochemical impedance spectroscopy(EIS), and electrochemical frequency modulation(EFM)techniques. Morphological analysis was performed on the uninhibited and inhibited C-steel using atomic force microscope(AFM) and Infrared Spectroscopy(ATR-IR) methods. The effect of temperature was studied and discussed. Inspection of experimental results revealed that the inhibition efficiency(IE) increases with the incremental addition of inhibitors and with elevating the temperature of the acid media. The adsorption of furanylnicotinamidine derivatives on C-steel follows Temkin's isotherm. PP studies indicated that the investigated compounds act as mixed-type inhibitors and showed that p-dimethylaminophenyl furanylnicotinamidine derivative(MA-1256) was the most efficient inhibitor among the other studied derivatives with IE reached(95%)at 21 × 10~(-6) mol·L~(-1). MA-1266 is highly soluble in aqueous solution and has non-toxicity profile with LC50 N 37 mg·L~(-1). Thus, MA-1266 can be a promising green corrosion inhibitor candidate with IE N 91% at 21× 10~(-6) mol·L~(-1). The experiments were coupled with computational chemical theories such as quantum chemical and molecular dynamic methods. The experimental results were in good agreement with the computational outputs.     

D72树脂对镨(Ⅲ)的吸附性能(英文)

In this work, the feasibility of using a macroporous strong acid ion exchange resin (D72) as an adsorbent for praseodymium (Ⅲ) was examined. The adsorption behavior and mechanism were investigated with various chemical methods and IR spectrometry. The results showed that the loading of Pr (III) ions was strongly dependent on pH of the medium and the optimal adsorption condition is in HAc-NaAc medium with pH value of 3.0. Adsorption kinetics of Pr (III) ions onto D72 resin could be best described by pseudo-second-order model. The maximum adsorption capacity of D72 for Pr (Ⅲ) was evaluated to be 294 mg·g 1 for the Langmuir model at 298K. The apparent activation energy, E a , was 14.71 kJ·mol 1 . The calculated data of thermodynamic parameters, ΔSΘ value of 100 J·mol 1 ·K 1 and ΔHΘ value of 8.89 kJ·mol 1 , indicate the endothermic nature of the adsorption process, while a decrease of ΔGΘ with increasing temperature indicates the spontaneous nature of the adsorption process. Finally, Pr (Ⅲ) can be eluted by using 1.00 mol·L 1 HCl-0.50 mol·L 1 NaCl solution and the D72 resin can be regenerated and reused. Thomas model was successfully applied to experimental data to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design. The characterization before and after adsorption of Pr (Ⅲ) ions on D72 resin was conformed by IR.     

2,5-二芳基-1,3,4-噻二唑衍生物的合成及缓蚀性能

合成4种2,5-二芳基-1,3,4-噻二唑化合物,即2,5-二苯基-1,3,4-噻二唑(DPTD),2,5-二(2-羟基苯)-1,3,4-噻二唑(2-DHPTD),2,5-二(3-羟基苯)-1,3,4-噻二唑(3-DHPTD)和2,5-二(4-羟基苯)-1,3,4-噻二唑(4-DHPTD)。通过Tafel极化曲线和电化学阻抗研究4种油溶型噻二唑衍生物在50 mg·L^-1硫-乙醇体系中的缓蚀性能,电化学测试表明:腐蚀液中添加噻二唑衍生物后,银片腐蚀得到抑制;随着缓蚀剂浓度增大,腐蚀电流密度减小,缓蚀效率增大;当缓蚀剂浓度为90 mg·L^-1时,4种缓蚀剂DPTD、2-DHPTD、3-DHPTD和4-DHPTD的缓蚀效率分别为85.8%、94.6%、96.4%和97.1%。采用扫描电子显微镜和原子力显微镜观察其表面形貌,可知缓蚀剂在金属表面形成一层保护膜,阻止腐蚀物质与金属表面的接触,从而抑制银片腐蚀。经分子动力学分析可知,4种噻二唑衍生物吸附于金属表面遵循Langmuir等温方程,且吸附属于以化学吸附为主的混合型吸附。量子化学计算和分子动力学模拟研究表明,4种缓蚀剂均具有很好的缓蚀作用,且4种缓蚀剂的缓蚀效率大小顺序是[4-DHPDT]> [3-DHPDT]> [2-DHPDT]> [DPDT],这与实验结果一致。     

铟、镓、铊金属离子通过色谱纤维支撑固态膜的传递行为(英文)

The transport of metal ions of indium, gallium and thallium from source solution to receiving phase through the chromatographic fiber supported solid membrane in the acetylacetone (HAA) containing mixed solvent system has been explored. The fibers supported solid membranes were prepared with chemical synthesis from cellulose fibers and citric acid with the carboxylic acid ion exchange groups introduced. The experimental variables, such as concentration of metal ions (10-2 to 10-4 mol·L-1) in the source solu...     

响应面方法分析代谢产物对类人胶原蛋白表达的影响

Recombinant Escherichia coli BL21 is used to produce human-like collagen. The key constituents of media are optimized using response surface methodology (RSM). Before thermal induction, the highest biomass production and the lowest production of some hazardous by-products, especially acetic acid, were obtained in the media containing 0.085 mol∙L1 glucose and 0.019 mol∙L1 nitrogen (carbon-nitrogen ratio, 4.47︰1). After thermal induction, when the concentrations of glucose and nitrogen in the media were 0.065 mol∙L1 and 0.017 mol∙L1, respectively (carbon-nitrogen ratio, 3.82︰1), the productivity of human-like collagen per cell was the highest while that of acetic acid was the lowest. The extended analysis showed that the production of lactic acid and propionic acid increased while that of some intermediate acids of the tricarboxylic acid cycle decreased if the dose of glucose in-creased.     

Implications from γ-globulin adsorption onto cation exchangers fabricated by sequential alginate grafting and sulfonation

Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate(Alg)-grafted re sin with an ionic capacity(IC) of 240 mmol·L~(-1)(Alg-FF-240).Moreover,the salt-tolerant feature of Alg-FF-230 was improved by using sequential alginate grafting and sulfonation strategy.Inspired by the enhanced adsorption performance of lysozyme,we have herein proposed to investigate the static and dynamic adsorption behaviors of γ-globulin on a series of Alg-grafted resins with different grafting densities and sulfonation degrees.The adsorption ca pacity of γ-globulin decreased with increa sing alginate-grafting density(IC) from 160 to 230 mmol·L~(-1) at 0 mmol·L~(-1) NaCl because of the steric hindrance caused by the alginate-grafting layer.Effects of ionic strength(IS) indicated that the adsorption capacities of the resins with the IC value of 230-370 mmol·L~(-1) were much higher than CM Sepharose FF at 50-100 mmol·L~(-1) NaCl,and the uptake rate of Alg-FF-230 was about twice as much as that of CM Sepharose FF.This work demonstrated the important effects of alginate-grafting layer and IS in γ-globulin adsorption behavior,which would be helpful in the design of Alggrafted resins and the selection of proper IS condition for protein purification.     

Removal of Cd（II） by Nanometer AIO（OH） Loaded on Fiberglass with Activated Carbon Fiber Felt as Carrier

A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution using column adsorption experiment. As was confirmed by XRD determination, the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO（OH）. SEM images showed that AlO（OH） particles were in the form of small aggregated clusters. The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd（II） adsorption on the new adsorbent. The results showed that the maximum adsorption capacity of Cd（II） was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g, respectively. The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution. Adsorption-desorption cycles showed the feasibility of repealed uses of the composited material. The adsorption capacities were influenced by pH and the initial Cd（II） concentration. The amount adsorbed was greatest at pH 6.5 and the initial Cd（II） concentration of 0.07 mg·L^-1, respectively. Nanometer AlO（OH） played a major role in the adsorption process, whereas the fiberglass and ACF were assistants in the process of removing Cd（II）. In addition, the adsorption capacities for Cd（II） were obviously reduced from 128.50 mg·L^-1 to 64.28 mg·L^-1 when Pb ions were present because Pb ions took up more adsorption sites.     

Recovery of lithium using H4Mn3.5Ti1.5O12/reduced graphene oxide/polyacrylamide composite hydrogel from brine by Ads-ESIX process

Powdery Li⁺-imprinted manganese oxides adsorbent was widely used to the recovery of Li⁺, but there are some difficulties, such as poor stability in acid solution, inconvenience of operation and separation. In this work, a useful hydrogel composite based H₄Mn_3.5Ti_1.5O₁₂/reduced graphene oxide/polyacrylamide (HMTO-rGO/PAM) was fabricated by thermal initiation method with promising stable, conductive and selective properties. The resulting materials were characterized by field emission scanning electron microscope, infrared absorption spectrum, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical techniques. The recovery of Li⁺ was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption process. The adsorption capacity of 51.5 mg·g^-1 could be achieved with an initial Li⁺ concentration of 200 mg·L^-1 in pH 10, at 45 ℃ for 12 h. Li⁺ ions could be quickly desorbed by cyclic voltammetry (CV) in pH 3, 0.1 mol·L^-1 HCl/NH₄Cl accompanying the exchange of Li⁺ and H⁺(NH₄⁺) and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.     

Hydrothermal synthesis of zeolitic material from circulating fluidized bed combustion fly ash for the highly efficient removal of lead from aqueous solution

The utilization of coal fly ash derived from circulating fluidized bed combustion(CFBFA) still faces great challenges because of its unique characteristics. In this study, a zeolitic material with Na-P1 zeolite as the main phase was successfully synthesized via a hydrothermal method by using CFBFA as the raw material.The effects of hydrothermal temperature, time, and added CTAB amount on the characterizations of synthesized materials were investigated by XRD, SEM, and XPS. The properties of the ...     

Potential-aided recovery of iodide using 2-D nanosheet CuxO coating polymer/graphene/carbon fibers composite

2-D nanosheet Cu_2O doped CuO coating poly m-phenylenediamine and melamine/graphene/carbon fibers composite(Cu_xO/MPM/GFs) was firstly fabricated by compound electrochemical method. Cu_xO/MPM/GFs was successfully used to the recovery of iodide(I~-) from salt water by lower potential-aided sorption and desorption processes. The potential-aided recovery of I~- at CuxO/MPM/GFs was characterized by FE-SEM, XRD, IR, Raman,XPS, UV–vis and electrochemical techniques in detail. The maximal adsorption capacity of 86.82 mg·g~(-1) could be obtained with a pseudo-second-order model at 0.8 V for 210 min in pH 5.0, 0.1 mol·L~(-1) NaCl, and the process accompanied the generation of CuI, CuO and I~(5-). The I-could be quickly desorbed from the electrode with a transfer of CuI to Cu_2O by cycle voltammetry from -1.0 to 0.5 V for 90 cycles in pH 9.0, 0.1 mol·L~(-1) KNO_3.Thus, CuxO/MPM/GFs was renewable in the continuous electrochemical-adsorption–desorption processes.     

离子液体金属配合物吸附废水中活性蓝19染料

以离子液体1-丁基-3-甲基咪唑溴代盐为原料, 合成含有离子液体咪唑基团和羟基基团的羟基化1-丁基-3-甲基咪唑离子液体铁配合物, 并将其用于活性染料的吸附。考察了该离子液体铁配合物对活性蓝19的吸附影响因素及吸附类型。结果表明当离子液体铁配合物的用量为0.02 g, 在pH为4～5, 活性蓝19染料的浓度为0.05 g·L^-1, 体积为3.0 ml, 吸附时间为15 s时, 离子液体铁配合物对活性蓝19染料的吸附率为98%。以0.1 mol·L^-1 NaOH作为解吸剂, 可实现对吸附的活性蓝的洗脱, 解吸率为60%, 活性蓝19的回收率为54%。基于以上吸附方法, 可实现对印染废水中活性蓝19染料的回收。     

具有羧酸官能团的功能性离子液体萃取分离钇的研究(英文)

A new kind of hydrophobic ionic liquids [1-alkyl-3-(1-carboxylpropyl)im][PF6] has been synthesized,and their extraction properties for Y(III) in the nitric acid medium was also investigated.The effects of extractant concentration,equilibrium pH of aqueous phase,salt concentration,temperature etc.were discussed.The results show that this kind of Task-Specific Ionic Liquid(TSIL) needs to be saponified before being used for the Y(III) ex-traction,and the extraction is acid dependent,and the extraction efficiency increases with the aqueous phase acidity decreasing.Furthermore,the loaded organic phase is easy to be stripped;more than 95% Y(III) could be stripped from the loaded organic phase when the stripping acidity is higher than 0.07 mol?L?1.The slope analysis technique is used to investigate the extraction mechanism,and a possible cation-exchange extraction mechanism is proposed in the present extraction system.     

膜蒸馏-结晶耦合从高浓度KCl-MgCl2-H2O溶液中回收KCl

用直接接触膜蒸馏处理高浓度的KCl和MgCl₂溶液,考察了盐水浓度(1.0～4.0 mol·L^-1)、循环流速(0.1～0.5 m·s^-1)对膜蒸馏性能的影响;结果表明:随着盐水浓度的升高,膜通量下降,这是由于盐溶液的蒸汽压(即溶液中水的活度)下降的缘故;当浓度超过3.0 mol·L^-1时,MgCl₂溶液的膜通量出现负值,这主要归结为MgCl₂溶液低的水的活度和高黏度的协同影响;提高循环流速,膜通量增大,尤其对高黏度的盐水(即MgCl₂溶液),增大流速对减少温度和浓度极化的影响更加有效。利用膜蒸馏-结晶耦合技术和间歇式操作,从高浓度KCl-MgCl₂-H₂O溶液中回收纯水和KCl结晶产品,考察了不同冷却方式对溶液过饱和度、KCl晶体形貌、粒度和粒度分布的影响。结果表明,自然冷却有利于形成形貌规整、粒度分布相对集中的结晶产品;在KCl降温过程中,自然冷却过程中的最大过冷度比快速降温过程小,从而有效地控制晶核形成的数量和晶体的生长速率。     

Synthesis of hierarchical dendritic micro–nano structure ZnFe_2O_4 and photocatalytic activities for water splitting

Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results show that the sample(S-2) is composed of pure ZnFe_2O_4 when the molar ratio of Zn~(2+)/Fe~(2+)in the electrolyte is 0.35. Decreasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-1) is composed of ZnFe_2O_4 and α-Fe_2O_3, whereas increasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn~(2+)/Fe: Zn at excess decreases the cell volume whereas Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV–Vis diffuse reflectance spectra were acquired by a spectrophotometer. The absorption edges gradually blue shift with the increase of the molar ratio of Zn~(2+)/Fe~(2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous olution containing 0.1 mol·L~(-1)Na_2S/0.02 mol·L~(-1)Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol·h-1· 0.02 g~(-1)was achieved by pure ZnFe_2O_4sample(S-2). The photocatalytic activity of the mixture phase of Zn Fe_2O_4 and α-Fe_2O_3(S-1) is better than ZnF e_2O_4 and ZnO(S-3).     

Direct synthesis of single-phase α-CaSO4·0.5H2O whiskers from waste nitrate solution

Single-phase α-CaSO₄·0.5H₂O whiskers were directly synthesized from waste Ca(NO₃)₂ solution using a hydrothermal method, and HNO₃ was synchronously regenerated. The effects of reaction temperature and Ca²⁺ concentration on the phase composition and morphology of products were determined by X-ray diffraction and optical microscopy. On the basis of the experimental results, the formation diagram of α-CaSO₄·0.5H₂O was plotted within the range of 5-35 g·L^-1 Ca²⁺ and 115℃-150℃. In addition, the conditions of the direct synthesis of α-CaSO₄·0.5H₂O were determined. Well-crystallized, single-phase α-CaSO₄·0.5H₂O whiskers with high aspect ratios (length, 1785 μm; diameter, 10.63 μm; aspect ratio, 168) and HNO₃ (70.25 g·L^-1) were obtained at the optimal conditions of 25 g·L^-1 Ca²⁺ and 125℃.     

Acid precipitation coupled membrane-dispersion advanced oxidation process (MAOP) to treat crystallization mother liquor of pulp wastewater

Treatment to crystallization mother liquor containing high concentration of organic and inorganic substances is a challenge in zero liquid discharge of industrial wastewater. Acid precipitation coupled membrane-dispersion advanced oxidation process(MAOP) was proposed for organics degradation before salt crystallization by evaporation. With acid–MAOP treatment CODCrin mother liquor of pulping wastewater was eliminated by 55.2% from ultrahigh initial concentration up to 12,500 mg·L~(-1). The decolorization rate was 96.5%. Recovered salt was mainly NaCl(83.3 wt%) having whiteness 50 brighter than industrial baysalt of whiteness 45. The oxidation conditions were optimized as CO_3= 0.11 g·L~(-1) and C_(H_2O_2)= 2.0 g·L~(-1) with dispersing rate 0.53 ml·min~(-1) for 100 min reaction toward acidified liquor of p H = 2. Acidification has notably improved evaporation efficiency during crystallization. Addition of H_2O_2 made through membrane dispersion has eliminated hydroxyl radical "quench effect" and enhanced the degradation capacity, in particular, the breakage of carbon–chloride bonds(of both aliphatic and aromatic). As a result, the proposed coupling method has improved organic pollutant reduction so as the purity of salt from the wastewater mixture which can facilitate water and salt recycling in industry.     

乳状液膜中1,3-桥连杯[4]芳烃/冠醚对碱金属离子的选择性萃取(英文)

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclu sion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of diacid calix[4]-1,3-crowns-4,5 were synthesized, and their inclusion-extraction parameters were optimized including the calixcrown scaffold （4.4%, by mass） as the carrier/demulsifier, the commercial kero sene as diluent in membrane, sulphonic acid （0.2 mol.L-1） and ammonium carbonate （0.4 mol.L-1） as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed （300 r.min-1）, and initial solute concentration （100 mg.L-1）. The selectivity of membrane over more than ten interfering cations was examined and the re sults reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98%-99%.     

Methane hydrate crystal growth on shell substrate

Hydrate crystals growth on the surface of methane bubble (hydrate film) in pure water was studied by using a high-pressure visible microscope under the conditions of subcooling ΔT = 5.44–13.72 K and methane concentration difference ΔC = 2.92–8.19 mol·L^-1. It was found the hydrate film is porous and the hydrate crystals grow towards the liquid phase on the film substrate. The crystal morphology and growth rate are affected by ΔT and ΔC. When ΔT < 8.82 K and ΔC < 4.12 mol·L^-1, the hydrate grows into scattered columnar crystals, and the axial growth rate of the crystal gradually decreases. When ΔT > 8.82 K or ΔC > 4.12 mol·L^-1, the hydrate crystals grow in dendritic shape, and the axial growth rate increases first and then decreases. The perimeter and area of the growing hydrate crystals were measured, and the fractal dimension of hydrate crystal under different ΔC and ΔT was calculated. The results show that the fractal dimension of columnar hydrate crystal is greater than 3. When 3.87 mol·L^-1 < ΔC < 4.20 mol·L^-1 and 7.4 K < ΔT < 8.8 K, the fractal dimension of columnar hydrate crystal is greater than 4; The fractal dimension of dendritic hydrate crystal is less than 3. When ΔC > 4.77 mol·L^-1, ΔT < 8.52 K, the fractal dimension of dendritic hydrate crystal is less than 2.     

The adsorption and corrosion inhibition of 8-hydroxy-7-quinolinecarboxaldehyde derivatives on C-steel surface in hydrochloric acid

The protection influence of 8-hydroxy-7-quinolinecarboxaldehyde derivatives against C-steel corrosion was studied in 2 mol· L-1 HCl solutions at 30 ℃.Measurements were conducted under various experimental conditions using weight loss,potentiodynamic polarization,electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques.These studies have shown that 8-hydroxy-7-quinolinecarboxaldehyde derivatives are very good "green",mixed-type inhibitors.Corrosion rates obtained from both EFM and EIS methods are comparable with those recorded using Tafel extrapolation method,confirming validation of corrosion rates measured by the latter.The inhibitive action of these 8-hydroxy-7-quinolinecarboxaldehyde derivatives was discussed in terms of blocking the electrode surface by adsorption of the molecules through the active centers contained in their structures following Langmuir adsorption isotherm.Quantum chemical method was also employed to explore the relationship between the inhibitor molecular properties and its protection efficiency.