Determination of Ammonium Ion in Lake Water by Voltammetry

An electroanalytical method for the determination of ammonium ion using a platinized platinum electrode is described. Under optimized analytical conditions, the linear range of the calibration graphs for ammonium ion is 3.0×10?5?5.0×10?3 mol·L?1 with a detection limit of 5.0×10?6 mol·L?1. The method has been applied to the determination of ammonium ion in lake water samples and recoveries of 100%–103% are obtained. The results obtained are found to be in good agreement with spectrophotometric results. Key words ammonium ion - voltammetry - platinized platinum electrode CLC number O 657.1 Foundation item: Supported by the National Natural Science Foundation of China (60171023)Biography: Wu Yun-hua (1971-), female, Ph. D candidate, research direction: bioelectrochemistry.

Migration process of ammonium ion in saturated silty sand and sandy loam

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Rocking-chair ammonium ion battery with high rate and long-cycle life

Aqueous rechargeable ammonium-ion batteries(AIBs)have drew considerable attention because of their capacity for high rates,low cost,and high safety.However,developing desired electrodes requiring stable structure in the aqueous fast ammoniation/de-ammoniation becomes urgent.Herein,an ammonium ion full battery using Cu_(3)[Fe(CN)_(6)]_(2)(CuHCF)acting to be a cathode and barium vanadate(BVO)acting to be an anode is described.Its excellent electrochemical behavior of Prussian blue analogs and the perfectly matched lattice structure of NH_(4)^(+)is expected.And the open structure of vanadium compounds satisfies the fast ammoniation/de-ammoniation of NH4+is also achieved.As a result of these synergistic effects,the BVO//CuHCF full cell retains 80.5 percent of its capacity following 1000 cycling.These achievements provide new ideas for developing low-cost and long-life AIBs.

Chemiluminescence flow Sensor for determination of the Ammonium ion

A novel chemiluminescence (CL) sensor for NH4+ combined with flow injection analysis is presented in this paper. It is based on the inhibition effect of NH4+ on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and hypochlorous acid electrogenerated on-line. The sensor responds linearly to NH4+ concentration in 1.0x10(-6)-4.0x10(-9) g/ml range. A complete analysis could be performed in 1 min. The system is stable for 200 determination.

Removal of Methylene Blue, Rhodamine B and Ammonium Ion from Aqueous Solution by Adsorption onto Sintering Porous Materials Prepared from Coconut Husk Waste

The present work was done in order to develop and find out suitable conversion methods for coconut husk wastes into value-added products. It is well-known that coconuts husk waste is hydrophobic therefore ethanol with different doses was used as a surfactant to enhance the removal efficiency. Treated samples at different adsorbent amounts, sintering temperatures & sintering time, stirring time, pH, and solution temperatures for color removal of Methylene Blue (MB) & Rhodamine B (RhB) and ammonium concentration were evaluated by using UV-Visible Spectroscopy. At 300°C, results showed complete removal for MB and more than 75% for RhB, whereas removal of ammonium ion reached around 52% when sintering product from husk waste was used. Further investigation was carried out for ammonium ion to understand the desorption kinetic behaviors and isotherm models. Kinetics indicated that desorption of ammonium ion followed pseudo-first order equation. Adsorption thermodynamic parameters such as ΔG, ΔH, and ΔS followed Van’t Hoff plot for adsorption and found to be negative which indicated that the adsorption process for ammonium onto coconut husk was physical, spontaneous and exothermic.

Cu-substituted nickel hexacyanoferrate with tunable reaction potentials for superior ammonium ion storage

In this work,a variety of Cu_(x)Ni_(2-x)Fe(CN)_(6)(x=0,0.4,0.8,1.2,1.6,2)cathodes for ammonium ion batteries are prepared and their electrochemical performances are investigated.During the introduction of copper in nickel hexacyanoferrate,the electrochemical performance varies without changing the structure of nickel hexacyanoferrate.The increase of Cu content in nickel hexacyanoferrate leads to the enhancement of reaction potential and capacity.Electrochemical results suggest that the substitution of Cu for Ni has a positive effect on improving the cycling stability and rate capacity of nickel hexacyanoferrate when x in Cu_(x)Ni_(2-x)Fe(CN)_(6)is less than 0.4.Therefore,Cu_(0.4)Ni_(1.6)Fe(CN)_(6)exhibits the best cycling per-formance(capacity retention of 97.54%at 0.3 C)and the highest rate capacity(41.4 mAh g^(-1)at 10 C)in Cu_(x)Ni_(2-x)Fe(CN)_(6).Additionally,the X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)tests also reveal that the structural evolution of Cu_(0.4)Ni_(1.6)Fe(CN)_(6)is highly reversible upon NH_(4)^(+)storage.Therefore,this work proposes a candidate material for ammoniumion batteries and offers a novel avenue for adjusting the operating potential of the material.

Enabling nickel ferrocyanide nanoparticles for highperformance ammonium ion storage

Prussian blue and its analogs are extensively investigated as a cathode for ammonium-ion batteries.However,they often suffer from poor electronic conductivity.Here,we report a Ni_(2)Fe(CN)_(6)/multiwalled carbon nanotube composite electrode material,which is prepared using a simple coprecipitation approach.The obtained material consists of nanoparticles with sizes 30-50 nm and the multiwalled carbon nanotube embedded in it.The existence of multiwalled carbon nanotube ensures that the Ni_(2)Fe(CN)_(6)/multiwalled carbon nanotube composite shows excellent electrochemical performance,achieving a discharge capacity of 55.1 mAh·g^(-1)at 1 C and 43.2 mAh·g^(-1)even at 15 C.An increase in the ammoniumion diffusion coefficient and ionic/electron conductivity based on kinetic investigations accounts for their high performance.Furthermore,detailed ex situ characterizations demonstrate that Ni_(2)Fe(CN)_(6)/multiwalled carbon nanotube composite offers three advantages:negligible lattice expansion during cycling,stable structure,and the reversible redox couple.Therefore,the Ni_(2)Fe(CN)_(6)/multiwalled carbon nanotube composite presents a long cycling life and high rate capacity.Finally,our study reports a desirable material for ammonium-ion batteries and provides a practical approach for improving the electrochemical performance of Prussian blue and its analogs.

Removal of ammonium ion from water by Na-rich birnessite:Performance and mechanisms

Na-rich birnessite（NRB） was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion（NH＋4） from aqueous solution.In order to demonstrate the adsorption performance of the synthesized material,the effects of contact time,pH,initial ammonium ion concentration,and temperature were investigated.Adsorption kinetics showed that the adsorption behavior followed the pseudo second-order kinetic model.The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption models and the model parameters were evaluated.The monolayer adsorption capacity of the adsorbent,as obtained from the Langmuir isotherm,was 22.61 mg NH＋4-N/g at283 K.Thermodynamic analyses showed that the adsorption was spontaneous and that it was also a physisorption process.Our data revealed that the higher NH＋4adsorption capacity could be primarily attributed to the water absorption process and electrostatic interaction.Particularly,the high surface hydroxyl-content of NRB enables strong interactions with ammonium ion.The results obtained in this study illustrate that the NRB is expected to be an effective and economically viable adsorbent for ammonium ion removal from aqueous system.

Switching Optimally Balanced Fe-N Interaction Enables Extremely Stable Energy Storage

The interaction between electrode materials and charge carriers is one of the central issues dominating underlying energy storage mechanisms.To address the notoriously significant volume changes accompanying intercalation or formation of alloy/compounds,we aim to introduce and utilize a weak,reversible Fe-N interaction during the(de)intercalation of ammonium ions(NH_(4)^(+))within iron(Ⅲ)hexacyanoferrate(FeHCF),inspired by manipulating the electrostatic adsorption between N and Fe in the early stages of ammonia synthesis(Bosch-Harber Process,Chemical Engineering)and steel nitriding processes(Metal Industry).Such strategy of switching well-balanced Fe-N interaction is confirmed in between the nitrogen of ammonium ions and highspin Fe in FeHCF,as observed by using X-ray absorption spectroscopy.The resulting material provided an extremely stable energy storage(58 mAh g^(-1) after 10000 cycles at current density of 1 A g^(-1))as well as high-rate performance(23.6 mAh g^(-1) at current density of 10 A g^(-1)).

Removal of vanadium from ammonium molybdate solution by ion exchange

The separation techniques of vanadium and molybdenum were summarized, and a new method of removal V(Ⅴ) from Mo(Ⅵ) by adsorption with chelate resin was presented. Nine kinds of chelate resins were used to investigate the adsorbent capability of V(Ⅴ) in ammonium molybdate solution with static method. The test results show that DDAS, CUW and CW-2 resins can easily adsorb V(Ⅴ) in ammonium molybdate solution, but hardly adsorb Mo(Ⅵ). The dynamic experimental results show more than 99.5% of V(Ⅴ) can be adsorbed, and the adsorption rate of Mo(Ⅵ) is less than 0.27% at 294-296 K for 60 min at pH 7.42-8.02. The mass ratio of V to Mo decreases to l/5 0000 in the effluent from 1/255 in the initial solution. The loaded resin can be desorbed by 5% NH3·H2O solution, and the vanadium desorption rate can reach 99.6%. The max concentration of vanadium in desorbed solution can reach 20 g/L, while the concentration of molybdenum is less than 0.8 g/L.

Adsorption of methyl orange from aqueous solution by composite magnetic microspheres of chitosan and quaternary ammonium chitosan derivative

Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions.The CHMMs were characterized by a scanning electron microscope,a transmission electron microscope,and Fourier transform infrared spectroscopy,respectively.Compared with the chitosan beads,the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size.The MO adsorption by CHMMs was investigated by batch adsorption experiments.The adsorption kinetics was conformed to the pseudo second-order kinetics equation.The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K.Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change(△H°) of 99.44 kJ·mol^-1.The CHMMs had a stable performance for MO adsorption in the pH range of 4-10,but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction.A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs.The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.

A NEW TECHNOLOGY FOR PRODUCTION O F HIGH PURITY PARATUNGSTATE AMMONIUM FROM LOW GRADE TUNGSTEN CONCENTRATE

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Adsorption of Ammonium and Heavy Metal Ions on Industrial Vermiculite from the Yuli Mine in Xinjiang, China

The present work discusses the mineralogy, saturated adsorption of ammonium and adsorption of heavy metal ions （Cu^2＋, Pb^2＋ and Zn^2＋） on industrial vermiculite samples from the Yuli Mine in Xinjiang Autonomous Region. The saturated adsorption capacity of ammonium and the affection factors of adsorption of Cu^2＋, Pb^2＋ and Zn^2＋ are discussed on the basis of the mineralogical characteristics of the industrial vermiculite samples. The saturated adsorption capacities of ammonium are between 56.02 and 98.42 mmol/100g. The time of adsorption equilibrium is about 30-60 min, and the pH values and concentration of the ion solution significantly affect the adsorption capacities of the heavy metal ions. The adsorption capabilities of the heavy metal ions on industrial vermiculite are almost the same in the low ion concentration solutions, characterized by a sequence of Zn^2＋〉Pb^2＋〉Cu^2＋ for adsorption capacity in solutions with relatively high ion concentration. The results have practical significance for the application of the industrial vermiculite to treating wastewater containing ammonium or heavy metal ions.

EXCHANGE ADSORPTION EQUILIBRIA OF AMMONIUM ON CATION-VERMICULITE MINERALS

Experiment was designed under different pH and temperature conditions to analysis the NH4+ exchange capacity of Na+-vermiculite,Ca2+-vermiculite and Mg2+-vermiculite clay minerals pre-treated using NaCl,CaCl2 and MgCl2 solutions respectively.The results indicated that the exchange reactions occurred most rapidly at the proceeding 80 minutes and approached to equilibrium by about 120 minutes.The exchange quantity of ammonium on the vermiculite(at initial ammonium concentration of 673mg/L)varied with pH with a peak value of 28.36mg/g on Na+-vermiculite,23.01mg/g on Ca2+-vermiculite,20.14mg/g on Mg2+-vermiculite,18.04mg/g on natural vermiculite at pH 7.The exchange and adsorption isotherm of NH4+ on cation-vermiculite can be described by Langmuir equation.

STUDIES ON SYNTHESIS AND CHARACTER OF INORGANIC ION EXCHANGER TITANIUM PHOSPHATE-AMMONIUM TUNGSTOPHOSPHATE

In this paper, a new complex inorganic ion exchanger Titanium Phosphate - Ammonium Tungstophosphate (abbreviated as TiP - AWP) was synthesized, whose exchange character and chemical structure were studied, Thiscompound exhibits high exchange capacity and selectivity for Cs+, its exchangecapacity attains 0. 95 mmol/g in the medium of 0. 1 mol/L HNO3, andwhich almost doesn’ t change in the 1 AW imitated waste solution. There areno change in exchange capacity and structure after several times of exchanging,eluting, regenerating, which is of great importance to the separation and uptaking of radio - nuclides. Further more, this exchanger has good thermal andradioactive stability.

Effects of Hydroxyl Groups in Organic Ammonium Counterions on the Properties of Fluorinated Surfactants

The surface tension, foaming and viscosity for C_7F_(15)COO^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x) and C_8F_(17)SO_3^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x)(x=0, 1,2, 3) were measured to systematically study the effects of hydroxyl groups in organic ammonium counterions on the properties of perfluorooctanoates and perfluorooctanesulfonates. The results showed that the critical micelle concentration (cmc) and the surface tension at cmc (γ_(cmc)) were both increased with the increase of number of hydroxyl groups (x) in the two series. The perfluorooctanesulfonate had smaller cmc but higherγ_(cmc) than perfluorooctanoate with the same counterion. The minimum molecular area of surface adsorption (A_(min)) of C_8F_(17)SO_3^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x) were 0.64, 0.57, 0.63 and 0.72 nm^2 while the A_(min) values of C_7F_(15)COO^-N^+H(C_2H_4OH)_x(C_2H_5)_(3-x) were 0.61, 0.62, 0.61 and 0.71 nm_2 when x=0, 1, 2 and 3,respectively. For the investigated systems of surfactants, the results of foam expansion ratio agreed with those of surface activity, while the 25% drainage time were consistent with the results of viscosity.

水系铵离子电池β-MnO_(2)正极材料的制备及性能研究

通过简单的水热法合成了隧道型β-MnO_(2)正极材料并应用于水系铵离子电池,并采用1 mol/L(NH4)2SO4水系电解液,在窗口电压为0~1.6 V范围内,测试其电化学性能。实验结果表明:β-MnO_(2)正极材料在0.1A/g电流密度下表现出109.8 mAh/g放电比容量,经过140次循环后,其放电比容量仍有101.9 mAh/g,容量保留率为92.8%,库伦效率接近100%,具有优异的循环稳定性能。同时还具有优异的倍率性能,β-MnO_(2)纳米棒正极材料即使在1.0 A/g大电流密度下仍有78.7 mAh/g。此外,通过非原位FTIR、XPS测试探索了其储铵机理,结果表明铵根离子具有良好的可逆性。

人类辅助生殖技术用液中铵离子含量影响因素分析

目的为人类辅助生殖技术(ART)用液产品中铵离子含量的控制及储存条件提供参考。方法选择市场上6个厂家17批不同作用的ART用液,使用离子色谱法测定铵离子含量,并分析储存温度和储存时间对铵离子含量的影响。结果货架有效期内,冷冻液套装、解冻液套装、培养液、处理液中铵离子含量分别为0.89~3.34µg/mL,0.88~4.68µg/mL,0.75~1.45µg/mL,0.38~3.89µg/mL。胚胎培养液中铵离子含量,37℃储存时30 d内从0.9µg/mL升至3.1µg/mL,4℃储存时240 d内从0.6µg/mL升至1.7µg/mL。结论不同作用ART用液中铵离子含量存在差异,且与产品的储存温度、储存时间呈正相关。在进行货架有效期制订时,应考虑产品中铵离子含量。

铵离子混合超级电容器电极材料研究进展

随着社会对能源需求的不断增长和传统能源的消耗,寻找可再生清洁能源已成为当务之急。铵离子混合电容器作为一种清洁且可持续的解决方案在电能存储领域备受关注。本文主要综述了铵离子混合电容器的研究进展,包括其优点以及当前存在的问题和挑战。同时,重点关注了电极材料的研究现状,如锰基氧化物、钒基氧化物、钼基化合物等,并展望了未来的发展方向。通过对铵离子混合电容器的研究现状进行全面分析,本文旨在为该领域的研究者提供有益的参考和启示。