Active Micelle Pumping Channel Triggers Nonequilibrium Surface Excess Aggregation.

Adsorbate transport during the electrochemical process mostly follows the electric-field direction or the high-to-low direction along the concentration gradient and thus often limits the reactant concentration at the adsorption site and requires specific mechanical or chemical bonds of adsorbates to trigger local excess aggregation for advanced framework structure assembly. Herein, we have discovered an active pumping channel during electrochemical adsorption of a manganese colloid, which follows a low-to-high direction inverse concentration gradient. It triggers surface excess micelle aggregation with even over 16-folds higher concentration than that in bulk owing to hydrogen-bonding difference of the micelle surface between in bulk and at the water surface. Micelles in the channel exhibit unique polymerization behaviors by directly polymerizing monomer micelles to form highly catalytic MnO2 of dendritic frameworks, which can serve as a scalable thin-layer aqueous-phase reactor. It increases the understanding of the interface-dependent dynamic nature of micelle or more adsorbates and inspires transformative synthesizing approaches for advanced oxide materials.

Highly efficient oxidation of chromium (III) with hydrogen peroxide in alkaline medium.

Many technologies have been proposed to oxidize chromium, such as roasting-water leaching technology and hydrometallurgical methods such as pressure oxidative leaching coupled with oxygen, ozone, permanganate and ferrate, but the problems associated with the high temperature, low overall resource utilization efficiency, high energy consumption, and the environmental pollution, still remain unsolved. This paper focuses on the oxidation process of chromium (III) with hydrogen peroxide (H2O2) in an alkaline medium. The effect of parameters including dosage of H2O2, dosage of NaOH, reaction time, reaction temperature and stirring rate on the oxidation efficiency of chromium were investigated. The oxidation efficiency was significantly affected by the dosage of H2O2 and NaOH, reaction time and reaction temperature took second place; last was the stirring rate. Oxidation efficiency was nearly 100% under the optimal conditions: volume ratio of H2O2 to mass of Cr2(SO4)3 of 2.4 mL/g, mass ratio of NaOH to Cr2(SO4)3 0.6 g/g, reaction time of 90 min, reaction temperature of 90 °C and stirring rate of 500 rpm.

Simultaneous stabilization/solidification of Mn2+ and NH4+-N from electrolytic manganese residue using MgO and different phosphate resource.

This study examined simultaneous stabilization and solidification (S/S) of Mn2+ and NH4+-N from electrolytic manganese residue (EMR) using MgO and different phosphate resource. The characteristics of EMR NH4+-N and Mn2+ S/S behavior, S/S mechanisms, leaching test and economic analysis, were investigated. The results show that the S/S efficiency of Mn2+ and NH4+-N could reach 91.58% and 99.98%, respectively, and the pH value is 8.75 when the molar ratio of Mg:P is 3:1 and the dose of PM (MgO and Na3PO4·12H2O) is 8wt%. In this process, Mn2+ could mainly be stabilized in the forms of Mn(H2PO4)2·2H2O, Mn3(PO4)2·3H2O, Mn(OH)2, and MnOOH, and NH4+-N in the form of NH4MgPO4·6H2O. Economic evaluation indicates that using PM process has a lower cost than HPM and HOM process for the S/S of Mn2+ and NH4+-N from EMR at the same stabilization agent dose. Leaching test values of all the measured metals are within the permitted level for the GB8978-1996 test suggested when the dose of PM, HPM and HOM is 8wt%.

Time-periodic oscillation reaction in an organic-solvent dominated electrolyte.

Time-periodic phenomena widely exist in natural life sustaining systems but are rarely reported in highly efficient artificial electrochemical energy-harvesting systems. Herein, we observed for the first time the periodic oscillation reaction in organic-solvent dominated electrolytes that could be also derived from some electrochemical energy harvesting cells. Owing to different reaction activity and acidity in the organic solvent, the oscillation reaction could occur under milder pH conditions and exhibit better durability. Its influence on electric output and related differences from an aqueous B-Z reaction are discussed from a mechanism point of view. Our findings may contribute to smart self-oscillation materials and new strategies for highly efficient long-term energy harvesting.

Adsorption kinetics and isotherm of vanadium with melamine.

Melamine, possessing three free amino groups and three aromatic nitrogen atoms in its molecule, has great potential as an adsorbent for metal ions. We investigated three impact factors of the adsorption process: the initial pH of the vanadium solution, contact time and reaction temperature. The adsorption kinetics could be accurately described by the pseudo-second-order kinetic model. Langmuir and Freundlich models fitted well with the experimental equilibrium data, and the maximal adsorption capacity was found to be 1,428.57 mg vanadium/g melamine, and the Freundlich model showed the adsorption is privilege type.

Periodic current oscillation catalyzed by δ-MnO2 nanosheets.

The oxygen evolution reaction (OER) is of wide interest for both fuel and hydrometallurgy applications. Different types of nanoscale MnO2 , varying from nanosheets to nanoneedles, are synthesized and assembled on the anode to investigate their catalytic effect on the nonlinear kinetics of the MnO2 -catalyzed OER at high current. For δ-MnO2 nanosheets, periodic current oscillations (PCO) occurr and occupy up to 40 % of the total energy consumption. The PCO can help to reduce the energy consumption under constant current conditions. Its amplitude could be twice of that for the previously reported MnO2 grown by an in situ electrochemical method. If the amount of γ-MnO2 nanoneedles increases, the oscillation disappears. For different Mn oxides, the rate constants of H2 O2 decomposition differ, resulting in changes in oscillation features. The results of this study may enable new ideas to improve the efficiency of industrial electrolysis and charging-discharging of supercapacitors.

Recyclable and Efficient Recovery of Ca and S from Phosphogypsum by Using Multistep Precipitation.

The resource utilization of phosphogypsum (PG) is the key to promote the green development of the phosphorus chemical industry. The natural environment and public safety are significantly threatened by the enormous volume of PG storage. In this study, Ca and S were successfully recovered from the PG via a multistep precipitation in the NaOH-BaCO3 system. The alkali solution can be recycled five times, with a first recovery ratio of about 97.9%, and the decomposition ratio of PG remained above 70% after five cycles. In addition, the recovery ratios of Ca and S in PG are 99.9 and 82.5%, respectively. The product of BaSO4 can be used as a weighting agent for oil and natural gas drilling mud. The BaSO4 can also be used as wave-absorbing materials, and its reflection loss value reaches 97.8% of the analytical purity BaSO4. This work provides a new idea for the efficient recycling of Ca and S in PG with an outstanding application prospect.

Influence of PUB2 on the Leveling Effect of Chip Copper Connection Electroplating: Mechanism and Applications.

The copper connectivity technique is essential for achieving electrical interconnection in wafer level packaging (WLP), system in packaging (SiP), and 3D packaging. The essential processing material for copper connectivity is a copper sulfate electroplating solution in which organic additives play a crucial role in the regularity of copper electrodeposition. In this study, electrochemical tests, X-ray diffraction, 3D profiling, and scanning electron microscopy were used to investigate the leveling effect and mechanism of polyquaternary ammonium urea-containing polymer (PUB2) in the process of copper electrodeposition on-chip copper connections. PUB2 has excellent polarization ability on the target surface, remains unaffected by the sulfur additive SPS and poly(ethylene glycol), and displays a strong ability to regulate the copper deposition rate of through-holes and surface wiring. The waviness of the wafer surface wiring was reduced from 130 to approximately 70 nm after optimizing the PUB2 concentration, and the surface roughness was reduced from 10 to approximately 7 nm. The coating was dispersed evenly, and the rate of through-hole filling was improved by 57%. This study not only examined PUB2 leveling performance and mechanisms but also devised a research method and system for electroplating additives to facilitate the development and application of new electroplating additives.

Promoting the Calcified Roasting of Vanadium Slag Based on the CeO2-Catalytic Oxidation Mechanism.

Calcification roasting-acid leaching is a clean, efficient, and environmentally friendly process, but in the roasting process, the local temperature is often too high, the heat release is not timely, and the heat transfer is blocked. Furthermore, the material is easy to sinter, which affects the final vanadium extraction effect. In this paper, a small amount of CeO2 was introduced in the roasting process of vanadium slag to promote the calcified roasting. The results showed that the vanadium leaching rate reached 93.17% with the addition of 0.1 wt % CeO2 at a roasting temperature of 750 °C, which was higher than that obtained without CeO2 addition (90.00%). The results of XPS, XRD, and SEM-EDS analyses confirmed that adding CeO2 to the roasted clinker significantly increased the proportion of pentavalent vanadium to the total vanadium by up to 28.64%. O2-TPD analysis revealed an enhanced chemisorbed oxygen with the CeO2-assisted roasting, indicated the activation of oxygen by CeO2, and resulted in an enhanced oxidation of vanadium. The work in this paper establishes an alternative route for catalytic oxidation-enhanced vanadium slag roasting, which can improve the utilization of vanadium slag at relatively lower temperatures under the action of CeO2 and is of positive significance in solving the problems of sintering and energy consumption in the roasting process.

Molecular Diodes Induced by a Schottky Barrier with a Gold-Silicon Doped Electrode.

To create complementary metal oxide semiconductor compatible molecular devices, more insights into the electrode property regarding its metal/semiconductor doping level and creating a functional molecular device are required. In this work, we constructed an EGaIn/alkanethiol/Au-Si molecular diode (with a rectification ratio R of 50.70) induced by Schottky barriers within a gold-silicon doped electrode instead of the functional property of molecules. The relationship between the rectification ratio and the number of methylene units in alkanethiol was analyzed, revealing a gradual increase in the ratio from 3.33 for C6H14S to 50.70 for C16H34S. The rectification ratio of the junction is well modulated by the temperature due to the change in the Schottky barrier. Such a mechanism is explained by the energy band diagrams of the surface space charge region and a combination of density functional theory and Keldysh-Green formalism calculations.

Ti/Ti4O7 Anodes for Efficient Electrodeposition of Manganese Metal and Anode Slime Generation Reduction.

Preventing lead-based anodes from causing high-energy consumption, lead pollution, and harmful anode slime emission is a major challenge for the current electrolytic manganese metal industry. In this work, a Ti4O7-coated titanium electrode was used as anode material (Ti/Ti4O7 anode) in manganese electrowinning process for the first time and compared with a lead-based anode (Pb anode). The Ti/Ti4O7 anode was used for galvanostatic electrolysis; the cathodic current efficiency improved by 3.22% and energy consumption decreased by 7.82%. During 8 h of electrolysis, it reduced 90.42% solution anode slime and 72.80% plate anode slime formation. Anode product characterization and electrochemical tests indicated that the Ti/Ti4O7 anode possesses good oxygen evolution activity, and γ-MnO2 has a positive catalytic effect on oxygen evolution reaction (OER), which inhibited anode Mn2+ oxidation reaction and reduced the formation of anode slime. In addition, the low charge-transfer resistance, high diffusion resistance, and dense MnO2 layer of the anode blocked the diffusion path of Mn3+ in the system and inhibited the formation of anode slime. The Ti/Ti4O7 anode exhibits excellent electrochemical performance, which provides a new idea for the selection of novel anodes, energy savings and emission reduction, and the establishment of a new mode of clean production in the electrolytic manganese metal industry.

Prediction and Effect Verification of Thiamine as a Leveling Agent in Chip Wafer Electroplating.

Thiamine, a nitrogen-containing heterocyclic compound, is explored for the first time as a novel leveling agent in this study. Based on the density functional theory (DFT) calculations and molecular dynamics (MD) simulations of the adsorption process of thiamine and the commonly used leveling agent JGB, the average values of the binding energies after equilibrium of thiamine and JGB are similar, which indicates that the thiamine molecules have strong bonding ability with the surface of copper and can be adsorbed tightly on the surface of copper. By cyclic voltammetry (CV) curve, thiamine was found to inhibit copper deposition and the inhibition effect was stronger than JGB. The chrono potential curve (CP) test found that the potential difference △η = 87 > 50 mV at high and low speeds of thiamine, which indicates that thiamine has the potential to be used as a leveling agent. Electrochemical impedance spectroscopy (EIS) testing found that thiamine inhibited copper precipitation by inhibiting the reactions of Cu2+ → Cu+ and Cu+ → Cu. According to electroplating experiments, thiamine has a leveling effect on wafer electroplating and can be used as a leveling agent because the copper layer on the wafer obtained by adding it has a smoother surface compared to the copper layer obtained without adding it. It was found that wafer electroplating does not require PEG, and only adding 55 mg/L Cl-, 6 mg/L SPS, and 4 mg/L thiamine as additives can achieve a good filling effect.

Microwave Reactor with Combined Rigid and Flexible Stirring Paddles for Improving Fluid Heating Uniformity in Soft Manganese Ore Leaching Processes.

In order to overcome the apparent limitations of the inhomogeneous nature of large-scale microwave heating of fluids, a microwave reactor with a rigid-flexible combined stirring paddle is used to heat fluids, destabilizing the hot spots present in the microwave heating of fluids process. An integrated multiphysics field simulation model for calculating the microwave heating process with fluid was created for the purpose of clarifying the temperature field dispersion and fluid flow patterns in the reactor. By using the proposed model, the rigid-flexible combined stirring paddle is compared with the conventional single- and double-layer stirring paddle to highlight the benefits of the rigid-flexible combined stirring paddle in improving fluid heating uniformity. It was found experimentally that the leaching rate of soft manganese ore was increased by 7.08 and 5.22% compared to conventional single and double stirred paddles, respectively. In addition, the optimal stirrer parameters were investigated by the response surface method.

Leaching of phosphate ores with lower dissolution of metallic impurities: the dual role of sodium oleate.

In this work, we report the use of surfactants to improve the performance of phosphate ore leaching while reducing the concentration of metallic impurities in the leaching solution. Based on the zeta potential analysis, sodium oleate (SOL) is determined as a suitable surfactant because it can change interfacial properties and improve ionic diffusion. This is experimentally demonstrated by the high leaching performance. After that, the reaction conditions on the leaching performance are systematically investigated. Under the optimal experimental conditions (SOL concentration of 10 mg L-1, sulfuric acid concentration of 1.72 mol L-1, leaching temperature of 75 °C, and leaching time of 180 min), a high phosphorus leaching efficiency of 99.51% is achieved. Meanwhile, the leaching solution presents a lower content of metallic impurities. Further measurements performed on the leaching residues indicate that the additive SOL can promote the growth of platy crystals and facilitate PO leaching. Overall, this work demonstrates that the SOL-assisted leaching method allows for highly-efficient utilization of PO and high-purity phosphoric acid production.

Role of Additives: Modified Hemihydrate Phosphogypsum Morphology and Enhanced Filtration Performance of Wet-Process Phosphoric Acid.

The morphology of hemihydrate phosphogypsum crystals is of vital importance in the hemihydrate-dihydrate (HH-DH) wet-process phosphoric acid production for high filtration strength. The morphology of hemihydrate phosphogypsum is commonly needlelike due to the strong acidic crystallization environment, which is unfavorable to the following filtration process. In this study, the crystal habit of hemihydrate phosphogypsum with a large aspect ratio was skillfully modified by additives to achieve a higher filtration strength. d-Glucitol (DG) reduces the theoretical aspect ratio of hemihydrate phosphogypsum crystals from 2.076 to 1.583 by interacting with the (002) face of CaSO4·0.5H2O preferentially, and poly(vinyl alcohol) (PVA) facilitates the aggregation of small grains to gather into a clusterlike structure. The modified morphologies of hemihydrate phosphogypsum have a lower bulk density and a larger porosity of the formed filter cake, which increases the filtration strength up to 45.9% when DG is added. Our work provides an in-depth explanation of the evolution mechanism of hemihydrate phosphogypsum morphology with the additives and its influence on the filtration performance. The improved filtration strength would reduce the water content of hemihydrate phosphogypsum and relieve the storage pressure of the phosphogypsum slag dump, which is meaningful to the clean production and process emission reduction of the phosphorus chemical industry.

[Preparation and characterization of N, S, F-codoped nanosize TiO2 with ionic liquid].

N, S, F-co-doped TiO2 visible-light response photocatalyst (N-S-F-TiO2) was prepared with TiCl4, thiourea and ionic liquid (C6 mim]+ [BF4) via the microwave-catalytic hydrolysis precipitation process followed by calcination in an NH3/N2 atmosphere. It was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffusion reflectance spectroscopy (UV-Vis/DRS). Results showed that it was high purity anatase. The Ti-O-N, Ti-O-S and Ti-S bonds were formed in the TiO2 crystal and F used to dope TiO2 in the form of TiOF2. In the visible region 400 -550 nm, it has strong absorption, and in 600-800 nm there was a strong absorption band. N-S-F-TiO2 prepared at volume ratio of [C6 mim]+ [BF4]- /H2O of 5/95 exhibited the highest photocatalytic activity, and the degradation ratio of methyl orange was 95% under visible-light irradiation for 200 min. Multi-element co-doped synergistic effect was demonstrated by enhancement of the absorption in the visible region and higher visible light photocatalytic activity for N-S-F-TiO2.

Rigid-Flexible Combined Impeller Enhancement in Leaching of Phosphate Rock: a Kinetics Study.

Conventional rigid impellers are frequently used in the leaching process of phosphate rock, which often form a symmetrical flow field in the reactor, leading to a reduction in the leaching efficiency. In this work, a rigid-flexible combined impeller was applied to the leaching process of phosphate rock to increase the leaching efficiency. The effects of the reaction temperature (T), sulfuric acid excess coefficient (ε), liquid-solid ratio (L/S), agitation speed (N), and leaching time (t) on the leaching of phosphate rock were investigated, and based on this, the leaching kinetics was studied. The results indicated that under the optimum parameters of a reaction temperature of 353 K, a sulfuric acid excess coefficient of 1.15, a liquid-solid ratio of 4.0 mL/g, an agitation speed of 280 rpm, and a leaching time of 120 min, the leaching rate of phosphate rock using the rigid-flexible combined impeller reached 89.1%, which was 7.1% higher than that of the conventional rigid impeller under the same electric energy consumption. The leaching process complied with the unreacted core shrinking model, and the reaction rate was controlled by product layer diffusion. The apparent rate equation of the leaching process was 1 - 2X/3 - (1 - X)2/3 = 2.06 × 10-3[ε]1.375[L/S]1.273[N]0.748 exp(-19.03 × 103/RT)·t, and the apparent activation energy was 19.03 kJ/mol. The numerical simulation and analysis of the leaching residue showed that the system temperature in the rigid-flexible combined impeller system was homogenized, and the mixing effect of reactants was enhanced through the multiposition movement of the flexible connection piece in the axial direction, so that the reactants participated in the chemical reaction more efficiently.

Chloride ion inhibition of electrochemical oscillations on the anode of an electrolytic manganese metal cell.

In industrial electrolytic manganese metal process, the energy consumption closely related to the electrolysis of cathode and anode. The effect of Cl- concentration on electrochemical oscillation at the anode of the electrolytic manganese metal cell was investigated. The results showed that the electrochemical oscillation at the anode was inhibited by Cl-, and the amplitude and frequency of the electrochemical oscillation decreased as the increase of Cl- concentration. When the concentration of Cl- was 2.68 g/L, the cathode and anode electrodes could be effectively activated, and the manganese current efficiency reached its minimum, correspondingly, the power consumption reached its maximum. In addition, the presence of the chloride reduced the production of MnO2 at the anode surface. ClO4- and free ions formed insoluble amorphous structures on the surface of the anode with the increase in reaction time and chloride ion concentration, and the insoluble amorphous structures prevented further generation of MnO2. Thus, electrolytic manganese metal energy consumption decreased.

A non-printed integrated-circuit textile for wireless theranostics.

While the printed circuit board (PCB) has been widely considered as the building block of integrated electronics, the world is switching to pursue new ways of merging integrated electronic circuits with textiles to create flexible and wearable devices. Herein, as an alternative for PCB, we described a non-printed integrated-circuit textile (NIT) for biomedical and theranostic application via a weaving method. All the devices are built as fibers or interlaced nodes and woven into a deformable textile integrated circuit. Built on an electrochemical gating principle, the fiber-woven-type transistors exhibit superior bending or stretching robustness, and were woven as a textile logical computing module to distinguish different emergencies. A fiber-type sweat sensor was woven with strain and light sensors fibers for simultaneously monitoring body health and the environment. With a photo-rechargeable energy textile based on a detailed power consumption analysis, the woven circuit textile is completely self-powered and capable of both wireless biomedical monitoring and early warning. The NIT could be used as a 24/7 private AI "nurse" for routine healthcare, diabetes monitoring, or emergencies such as hypoglycemia, metabolic alkalosis, and even COVID-19 patient care, a potential future on-body AI hardware and possibly a forerunner to fabric-like computers.