scholarly journals Highly efficient removal of thallium(I) by facilely fabricated amorphous titanium dioxide from water and wastewater

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Gaosheng Zhang ◽  
Jinglin Luo ◽  
Hanlin Cao ◽  
Shengping Hu ◽  
Huosheng Li ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
High Efficiency ◽  
Ph Value ◽  
Hydroxyl Group ◽  
Precipitation Method ◽  
Solution Ph ◽  
Surface Complexes ◽  
Environmental Friendliness ◽  
Mining Wastewater ◽  
The One

AbstractIn this study, amorphous hydrous titanium dioxide was synthesized by a facile precipitation method at room temperature, aiming to effectively remove thallium(I) from water. The titanium dioxide prepared using ammonia as precipitant (TiO2I) is more effective for thallium(I) uptake than the one synthesized with sodium hydroxide (TiO2II). The TiO2 obtained particles are amorphous, aggregates of many nanoparticles and irregular in shape. The thallium(I) uptake increases with the rise of solution pH value. Under neutral pH conditions, the maximal thallium(I) adsorption capacities of TiO2I and TiO2II are 302.6 and 230.3 mg/g, respectively, outperforming most of the reported adsorbents. The amorphous TiO2 has high selectivity towards thallium(I) in the presence of multiple cations such as K+, Ca2+, Mg2+, Zn2+ and Ni2+. Moreover, the TiO2I is efficient in removing thallium(I) from real river water and mining wastewater. Additionally, the spent TiO2I can be regenerated using hydrochloric acid solution and reused. The Tl(I) adsorption is achieved via replacing the H+ in hydroxyl group on the surface of TiO2 and forming inner-sphere surface complexes. Owing to its high efficiency, facile synthesis and environmental friendliness, the TiO2I has the potential to be used as an alternative adsorbent to remove Tl(I) from water.

scholarly journals Facile synthesis of a high purity α-MnO2 nanorod for rapid degradation of Rhodamine B

2021 ◽  
Author(s):  
shumin wang ◽  
Ao Guan ◽  
Jiahan Wang ◽  
Xiaofang Fu ◽  
Xiang Guo ◽  
...  
Keyword(s):  
Rhodamine B ◽  
High Efficiency ◽  
Catalytic Mechanism ◽  
Ph Value ◽  
Removal Rate ◽  
Precipitation Method ◽  
Characteristic Peak ◽  
Catalytic Stability ◽  
Rapid Removal ◽  
Co Precipitation

Abstract Manganese dioxide (α-MnO2) nanorods with diameters of about 5-15 nm and lengths of 100-150 nm were synthesized by a simple co-precipitation method. XRD, TEM, HRTEM, SAED and XPS were used to analyze the crystallographic information, microstructure and chemical bonding of the as-prepared sample. The α-MnO2 nanorod exhibited a high efficiency and rapid removal rate of rhodamine B (RhB), which reached about 97.5% within 10 min when pH=4 (and pH=6.6) and 97.7% within 50 min when pH = 9 in the presence of H2O2. The results also indicated that a lower pH value is conducive to the movement of the characteristic peak and the attenuation of the intensity of the characteristic peak of RhB dye. Then a possible catalytic mechanism was revealed. Moreover, the α-MnO2 nanorod exhibits an excellent recyclability and catalytic stability. This research indicates that α-MnO2 nanorods have a potential application in practical dye pollutant treatment.

Phosphate removal from aqueous solution by Fe-La binary (hydr)oxides: A study of batch experiments and mechanisms

2021 ◽  
Author(s):  
Haijing Duan ◽  
Lin Zhang ◽  
Yu-long Wang ◽  
Yanhong Liu ◽  
Yangyang Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Ph Value ◽  
Phosphate Removal ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Batch Experiments ◽  
Exchange Reactions ◽  
X Ray ◽  
Co Precipitation

Abstract In this study, Fe-La binary (hydr)oxides were prepared by a co-precipitation method for phosphate removal. Various techniques, including secondary electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), powder X-ray diffraction (p-XRD) and Brunauer-Emmett-Teller (BET) surface area analysis, were employed to characterize the synthesized Fe-La binary (hydr)oxides. Batch experiments indicated that the performance of phosphate removal by Fe-La binary (hydr)oxides was excellent and increased with increasing La contents. The kinetics study showed that the adsorption was rapid and described better by the pseudo-second-order equation. The maximum adsorption capacities of Fe/La 3:1, Fe/La 1:1 and Fe/La 1:3 binary (hydr)oxides at pH 4.0 calculated by Langmuir model were 49.02, 69.44 and 136.99 mg/g, respectively. The uptake of phosphate was highly affected by solution pH and significantly reduced with the increase of pH value. The analyses of p-XRD, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) suggested that the predominant mechanisms of phosphate removal involved surface hydroxyl exchange reactions and co-precipitation of released La3+ and phosphate ions, which resulted into the formation of amorphous phase of rhabdophane (LaPO4∙0.5H2O). The results show great potential for the application on the treatment of phosphate decontamination for their high efficiency of phosphate removal.

scholarly journals Experimental study on single factor effect of divergent ultrasonic degradation of methylene blue in water

2019 ◽  
Vol 118 ◽  
pp. 03051
Author(s):  
Yong-guang Bi ◽  
Xin-ting Zhang ◽  
Shao-qi Zhou
Keyword(s):  
Methylene Blue ◽  
Degradation Rate ◽  
Ph Value ◽  
Methylene Blue Solution ◽  
Solution Ph ◽  
Environmental Friendliness ◽  
Initial Concentration ◽  
Highly Active ◽  
Blue Solution ◽  
Ultrasonic Degradation

The study of divergent ultrasonic degradation of methylene blue in water was carried out by exploring the ultrasonic intensity of the methylene blue, the initial concentration and the degradation rate of the solution pH. The test results show that the degradation rate of methylene blue decreases with the increase of ultrasonic power.The initial concentration of methylene blue solution is in the range of 0.00-10.00 mg/L. The degradation rate of methylene blue increases as the concentration of the solution increases. when the concentration is greater than 10.00mg/L, the concentration increases, and the ultrasonic degradation rate decreases. When the pH value is higher, the degradation rate of the methylene blue solution increases with the increase of pH, and the degradation rate reaches a maximum of 77.89%. The region where the ultrasonic degradation of methylene blue occurs is mainly at the junction of gas-liquid two phases, and is degraded by forming hydrogen peroxide in the cavitation bubbles and decomposing into various highly active radicals. Ultrasound has the advantages of fast, low energy consumption and environmental friendliness.

scholarly journals Determination of Iron Valence States Around Pits and the Influence of Fe3+ on the Pitting Corrosion of 304 Stainless Steel

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 726
Author(s):  
Zhang ◽  
Du ◽  
Wang ◽  
Zhao ◽  
Zhou
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Ph Value ◽  
Ion Concentration ◽  
304 Stainless Steel ◽  
Solution Ph ◽  
Valence States ◽  
The One ◽  
Iron Valence

Potassium ferricyanide and potassium ferrocyanide were used to observe and monitor the pitting corrosion of 304 stainless steel (SS) at anodic polarization in situ. The results show that there are Fe3+ ions around the corrosion pit when pitting occurs on 304 SS in NaCl aqueous solution. The effect of Fe3+ surrounded pits on the pitting corrosion was also studied by testing the electrochemical behavior of 304 SS in different Fe3+/Fe2+ solutions. The presence of Fe3+ leads to the positive shift of corrosion potential and the increase of corrosion rate of 304 SS. There are two possible reasons for this phenomenon. On the one hand, Fe3+ hydrolysis results in the decrease of pH value of solution. At the same iron ion concentration, the higher the Fe3+ ion concentration, the lower the solution pH value. On the other hand, Fe3+ may reduce on the electrode surface. The decrease of solution pH and the reduction of Fe3+ resulted in the acceleration of the corrosion rate.

Preparation of MgAl2O4 Nanopowder by Homogeneous Precipitation Method

2007 ◽  
Vol 280-283 ◽  
pp. 587-590 ◽  
Author(s):  
Xiao Lin Jia ◽  
Xiang Chong Zhong
Keyword(s):  
Ph Value ◽  
Particle Diameter ◽  
Ammonium Bicarbonate ◽  
Precipitation Method ◽  
Homogeneous Precipitation ◽  
Solution Ph ◽  
Homogeneous Precipitation Method ◽  
Surface Active Agents ◽  
Metallic Salt ◽  
Suitable Amount

MgAl2O4 nanopowder is synthesized by homogeneous precipitation method, using MgCl2,AlCl3 and ammonium bicarbonate as starting materials. The influences of the concentration of metallic salt solution, pH value and type and concentration of surface-active agents on agglomeration have been discussed. The results show that with addition of suitable amount of anion surface-activeagent, MgAl2O4 nanopowder with particle size of less than 12nm and secondary particle diameter of less than 170nm can be obtained by heated precursor at 850°C for 1h.

scholarly journals On Performance of Sparse Fast Fourier Transform Algorithms Using the Aliasing Filter

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1117
Author(s):  
Bin Li ◽  
Zhikang Jiang ◽  
Jie Chen
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
High Efficiency ◽  
Theory And Practice ◽  
Long Time ◽  
And Performance ◽  
Binary Tree Search ◽  
The One ◽  
Sparse Fast Fourier Transform ◽  
L1 And L2

Computing the sparse fast Fourier transform (sFFT) has emerged as a critical topic for a long time because of its high efficiency and wide practicability. More than twenty different sFFT algorithms compute discrete Fourier transform (DFT) by their unique methods so far. In order to use them properly, the urgent topic of great concern is how to analyze and evaluate the performance of these algorithms in theory and practice. This paper mainly discusses the technology and performance of sFFT algorithms using the aliasing filter. In the first part, the paper introduces the three frameworks: the one-shot framework based on the compressed sensing (CS) solver, the peeling framework based on the bipartite graph and the iterative framework based on the binary tree search. Then, we obtain the conclusion of the performance of six corresponding algorithms: the sFFT-DT1.0, sFFT-DT2.0, sFFT-DT3.0, FFAST, R-FFAST, and DSFFT algorithms in theory. In the second part, we make two categories of experiments for computing the signals of different SNRs, different lengths, and different sparsities by a standard testing platform and record the run time, the percentage of the signal sampled, and the L0, L1, and L2 errors both in the exactly sparse case and the general sparse case. The results of these performance analyses are our guide to optimize these algorithms and use them selectively.

scholarly journals Ionic Liquid-Assisted Synthesis of Ag3PO4 Spheres for Boosting Photodegradation Activity under Visible Light

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 788
Author(s):  
Beibei Zhang ◽  
Lu Zhang ◽  
Yulong Zhang ◽  
Chao Liu ◽  
Jiexiang Xia ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Visible Light ◽  
High Efficiency ◽  
Chemical Precipitation ◽  
Active Species ◽  
Precipitation Method ◽  
Dihydrogen Phosphate ◽  
Xrd Pattern ◽  
Simple Chemical ◽  
Visible Light Driven

In this work, a simple chemical precipitation method was employed to prepare spherical-like Ag3PO4 material (IL-Ag3PO4) with exposed {111} facet in the presence of reactive ionic liquid 1-butyl-3-methylimidazole dihydrogen phosphate ([Omim]H2PO4). The crystal structure, microstructure, optical properties, and visible-light photocatalytic performance of as-prepared materials were studied in detail. The addition of ionic liquids played a crucial role in forming spherical-like morphology of IL-Ag3PO4 sample. Compared with traditional Ag3PO4 material, the intensity ratio of {222}/{200} facets in XRD pattern of IL-Ag3PO4 was significantly enhanced, indicating the main {111} facets exposed on the surface of IL-Ag3PO4 sample. The presence of exposed {111} facet was advantageous for facilitating the charge carrier transfer and separation. The light-harvesting capacity of IL-Ag3PO4 was larger than that of Ag3PO4. The photocatalytic activity of samples was evaluated by degrading rhodamine B (RhB) and p-chlorophenol (4-CP) under visible light. The photodegradation efficiencies of IL-Ag3PO4 were 1.94 and 2.45 times higher than that of Ag3PO4 for RhB and 4-CP removal, respectively, attributing to a synergy from the exposed {111} facet and enhanced photoabsorption. Based on active species capturing experiments, holes (h+), and superoxide radical (•O2−) were the main active species for visible-light-driven RhB photodegradation. This study will provide a promising prospect for designing and synthesizing ionic liquid-assisted photocatalysts with a high efficiency.

scholarly journals Separation of Radionuclides from a Rare Earth-Containing Solution by Zeolite Adsorption

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Deniz Talan ◽  
Qingqing Huang
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Contact Time ◽  
Separation Efficiency ◽  
Ph Value ◽  
Solid Phase ◽  
Separation Performance ◽  
Solution Ph ◽  
Zeolite Sample ◽  
Alternative Sources

The increasing industrial demand for rare earths requires new or alternative sources to be found. Within this context, there have been studies validating the technical feasibility of coal and coal byproducts as alternative sources for rare earth elements. Nonetheless, radioactive materials, such as thorium and uranium, are frequently seen in the rare earths’ mineralization, and causes environmental and health concerns. Consequently, there exists an urgent need to remove these radionuclides in order to produce high purity rare earths to diversify the supply chain, as well as maintain an environmentally-favorable extraction process for the surroundings. In this study, an experimental design was generated to examine the effect of zeolite particle size, feed solution pH, zeolite amount, and contact time of solid and aqueous phases on the removal of thorium and uranium from the solution. The best separation performance was achieved using 2.50 g of 12-µm zeolite sample at a pH value of 3 with a contact time of 2 h. Under these conditions, the adsorption recovery of rare earths, thorium, and uranium into the solid phase was found to be 20.43 wt%, 99.20 wt%, and 89.60 wt%, respectively. The Freundlich adsorption isotherm was determined to be the best-fit model, and the adsorption mechanism of rare earths and thorium was identified as multilayer physisorption. Further, the separation efficiency was assessed using the response surface methodology based on the development of a statistically significant model.

Separation of phenols from oils using deep eutectic solvents and ionic liquids

2020 ◽  
Vol 92 (10) ◽  
pp. 1717-1731
Author(s):  
Yucui Hou ◽  
Zhi Feng ◽  
Jaime Ruben Sossa Cuellar ◽  
Weize Wu
Keyword(s):  
Ionic Liquids ◽  
Phenolic Compounds ◽  
High Efficiency ◽  
Deep Eutectic Solvents ◽  
Environmentally Benign ◽  
Organic Chemical ◽  
Environmental Friendliness ◽  
Oil Mixtures ◽  
Organic Chemical Industry

AbstractPhenolic compounds are important basic materials for the organic chemical industry, such as pesticides, medicines and preservatives. Phenolic compounds can be obtained from biomass, coal and petroleum via pyrolysis and liquefaction, but they are mixtures in oil. The traditional methods to separate phenols from oil using alkaline washing are not environmentally benign. To solve the problems, deep eutectic solvents (DESs) and ionic liquids (ILs) have been developed to separate phenols from oil, which shows high efficiency and environmental friendliness. In this article, we summarized the properties of DESs and ILs and the applications of DESs and ILs in the separation of phenols and oil. There are two ways in which DESs and ILs are used in these applications: (1) DESs formed in situ using different hydrogen bonding acceptors including quaternary ammonium salts, zwitterions, imidazoles and amides; (2) DESs and ILs used as extractants. The effect of water on the separation, mass transfer dynamics in the separation process, removal of neutral oil entrained in DESs, phase diagrams of phenol + oil + extractant during extraction, are also discussed. In the last, we analyze general trends for the separation and evaluate the problematic or challenging aspects in the separation of phenols from oil mixtures.

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