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The regeneration of Fe(II) is the rate-limiting step in the Fenton/Fenton-like chain reactions that seriously hinder their scientific progress towards practical application. In this study, we proposed iron boride (FeB) for the first time as a new material to sustainably decompose H

Many reagents as electron sacrificers have been recently investigated to induce decomposition of permanganate (KMnO4) to produce highly reactive intermediate Mn species toward oxidation of organic contaminants; however, this strategy meanwhile causes low KMnO4 utilization efficiency. This study surprisingly found that graphite can mediate direct electron transfer from organics (e.g., sulfamethoxazole (SMX)) to KMnO4, resulting in high KMnO4 utilization efficiency, rather than reductive sites of graphite-induced conversion of KMnO4 to highly reactive intermediate Mn species. The galvanic oxidation process (GOP) and comparative experiments of different organic contaminants prove that the KMnO4/graphite system mainly extracts electrons from organic contaminants via a one-electron pathway instead of a two-electron pathway. More importantly, the KMnO4/graphite system has superior reusability, graphite can keep a long-lasting reactivity, and the KMnO4 utilization efficiency elevates significantly after each cycle of graphite. The transformation of SMX in the KMnO4/graphite system mainly includes self-coupling, hydroxylation, oxidation, and hydrolytic reaction. The work will improve insights into the electron-transfer mechanism and unveil the advantages of efficient KMnO4 utilization in the KMnO4-based technologies in environmental remediation.

The carbon nanotubes (CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field. Herein, a mini-review of CNTs-based materials currently studies for organic pollutant elimination is presented. This review summarizes the preparation methods of CNTs-based materials. CNTs-based materials can be used as adsorbents to remove organic pollutants in wastewater. The adsorption mechanisms mainly include surface diffusion, pore diffusion and adsorption reaction. Most importantly, an in-depth overview of CNTs-based materials currently available in advanced oxidation processes (AOPs) applications for wastewater treatment is proposed. CNTs-based materials can catalyze different oxidants (e.g., hydrogen peroxide (H2O2), persulfates (PMS/PDS), ozone (O3) and ferrate/permanganate (Fe(VI)/Mn(VII)) to generate more reactive oxygen species (ROS) for organic pollutant elimination. Moreover, the possible reaction mechanisms of removing organic pollutants by CNTs-based materials are summarized systematically and discussed in detail. Finally, application potential and future research directions of CNTs-based materials in the environmental remediation field are proposed.

Reduction of Fe(III) is the rate-limiting step of iron induced Fenton-like systems, such as the iron/peroxydisulfate system, reducing agents (RAs) were frequently employed as electron donors to directly reduce Fe(III) to further promote the formation of reactive oxygen species (ROS), mainly including hydroxyl radical (

Unlike the other studies on emotional design in multimedia learning, the present study differentiated the two confounding variables of visual interface design and structured content to manipulate the instructional material. Specifically, we investigated how the visual aesthetics of positive emotional interface design influenced learners’ cognitive processes, emotional valences, learning outcomes, and subjective experience. Eighty-one college students took part in the experimental study. They were divided into the three experimental groups: a holistic layout of positive emotional design group (HPED), a local layout of positive emotional design group (LPED), and a neutral emotional design group (ND). By using a mixed approach of questionnaires and eye tracking, we further explored the differences among the three groups in cognitive processing, learning outcomes, and subjective experience. Results indicated that the LPED group invested higher cognitive effort, put more attentional focus in the relevant knowledge content module, and achieved better learning performance (i.e., retention and transfer tests) in contrast to the HPED group and the ND group. However, no significant difference in dynamic changes of emotional state among the three groups was detected. The analytical results can provide researchers and practitioners with valuable insights into the positive emotional design of multimedia learning, which allows for the facilitation of mental engagement, learning outcomes and subjective perception.

Slagging is a major problem in boilers, especially the low-rank coal applied in boilers. In this study, the influence of heat transfer surface on the slagging characteristics of a pilot-scale furnace was investigated. Ni coatings were applied in modifying the deposition surface to control slagging. The growth characteristics of the slag were studied using an online digital image technique. Scanning electron microscopy linked with energy-dispersive X-ray analysis and X-ray diffraction (XRD) were applied to investigate the microstructure, semi-quantitative chemical composition, and mineralogy of slag samples. Ni coating demonstrated a positive effect on the mitigation of slagging. Results revealed that the thicknesses of the slag initially increased with experimental time and then inclined toward stable values for both cases (Case 1: substrate material; Case 2: modified surface). The stable thicknesses for Cases 1 and 2 were 4.91 mm and 3.95 mm, respectively. The heat transfer efficiency was improved by approximately 18.2% with the application of Ni coating for probe surface modification. The mechanism of the mitigation of slagging was investigated in this study. XRD results revealed that the content of alkali reduced when the surface was coated with Ni. The alkali significantly affected the adhesion behavior of the deposition. Hence, Ni coating showed potential in reducing slagging and increasing the efficiency of boilers. The overall study makes a contribution to a deep understanding of the effect of Ni coating on the growth characteristics of the slag.

Biochar produced by the pyrolysis of biomass can be used to counter water pollution from heavy metals. The purpose of this work was to develop a biosorbent based on soy sauce residue (SSR) for the removal of Cr6+ and Pb2+. The SSR biochar (SBC) from oxygen-limited pyrolysis under the temperatures of 300 to 700 °C were obtained, and their adsorption capability was evaluated. After determining the optimum pyrolysis temperature, the effects of initial pH values, contact times, and initial metal concentrations on the Cr6+ and Pb2+ adsorption by SBC prepared at 600 °C (SBC600) were investigated. With the increase of pyrolysis temperature, the physical and chemical properties of SBC developed in a direction favorable to heavy metal adsorption. The SBC600 reached the adsorption equilibrium at the time of 2 (Cr6+) and 24 h (Pb2+), and the maximum adsorption amounts of Cr6+ and Pb2+ were 25.80 and 135.3 mg/g, respectively. The adsorption kinetics followed the pseudo-second-order kinetic equation, and the adsorption isotherms was best described by the Langmuir isotherms. The SBC was an adsorbent with certain potential for heavy metals removal in wastewater.

The sluggish kinetics of Fe(II) recovery strongly impedes the scientific progress of Fenton reaction (Fe(II)/H

Coal and biomass co-combustion in existing utility boilers is a promising option of mitigating the fossil energy crisis and reducing the gaseous emissions of NOx, SOx, and CO2. However, ash-related problems including fouling, slagging, and corrosion cause damage to heat exchange tube and reduce boiler efficiency. In an attempt to give better insights into slagging behavior during coal/biomass combustion, an experimental investigation was conducted to study the growth of slag when coal was co-fired with wood and corn stalk in a 300 kW pilot-scale furnace. For comparison, combustion of pure coal was also conducted. During the experiments, biomass proportions of 5% and 10% by weight were examined. Slags formed on an oil-cooled deposition probe were collected, sampled and analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Change in slag thickness with time was obtained by a CCD monitoring system. With two thermocouples in the probe, the heat flux through the slag could be measured....

The gap of pollutant concentration between simulated sewage (mg/L level) and actual water (μg/L level) strongly limits the application of advanced oxidation processes (AOPs) in natural waters. By coupling adsorption for gathering trace organic contaminants and in-situ catalytic oxidation for recovering adsorption capability, adsorptive catalysts can build a bridge between theoretical research and practical application to promote scientific progress of AOPs. Here, waste leather derived biochar based adsorptive catalysts (WLBC) can effectively adsorb trace sulfamethoxazole (SMX) via electrostatic attraction, hydrophobic interaction, π-π interaction, and Van der Waals forces, moreover, the subsequent in-situ oxidation of surface SMX by hydroxyl radical (•OH) generated from WLBC mediated Fenton-like reaction will recover the adsorption capability of WLBC. Compared with persulfate-driven AOPs, •OH-dominated oxidation is nonselective for various pollutants and effective for adsorbent regeneration. In addition, the pathway of SMX degradation was proposed based on the results of liquid chromatography-quadrupole time of flight-mass spectrometer (LC-QTOF-MS), involving four stages of 1) nitration, hydroxylation, and hydrolytic reaction of SMX, 2) cleavage of S-N and S-C bonds, 3) ring-opening, 4) mineralization. The adsorption and in-situ Fenton-like oxidation system established by WLBC is capable of efficiently degrading trace pollutants and regenerating adsorbent for long-scale operation, which immunes largely from coexisting substances (e.g. anions, cations, and humic acid) with extremely low metal leaching and relatively low cost. Therefore, this study proposes a strategy for sustainable removal of trace organic pollutant in natural waters based on coupling WLBC induced adsorption and in-situ Fenton-like oxidation.

In this review, we systematically summarized the origins, development, basic mechanism and limits of reductant-enhanced iron-based peroxide activation processes (including H2O2, peroxymonosulfate and peroxydisulfate). Notably, the use of reductants would simultaneously accelerate the reduction of Fe3+ and quench the production of reactive species. This trade-off between Fe3+ reduction and reactive species consumption is mainly determined by two aspects, i.e. (i) intrinsic chemical properties like electron transfer pathways and reaction rates with reactive species, and (ii) experimental conditions like reagent dosage ratio, dissolved O2 and pH. Therefore, we first reviewed the characteristics of different iron/peroxide/reductant systems in terms of the above two aspects. Then, we evaluated the practical application potential of different reductants based on their toxicity, costs and self-transformation products. Finally, newly-emerging enhancement strategies like multiple dosing and regulation of phase and crystalline degree were summarized, and future research needs were proposed.

Single-atom catalysts (SACs) have attracted considerable attention from researchers because of their distinct structures and characteristics, especially in maximizing atomic utilization and elevating the intrinsic catalytic activity. More recently, SACs have been becoming a burgeoning area of the environmental field and are extensively applied to remove various refractory organic pollutants. This review summarizes the emerging synthetic and characterization strategies of SACs and analyzes their development tendency. Besides, the application of SACs in advanced oxidation processes (AOPs, e.g., catalysis of H2O2, activation of persulfates and photocatalysis) is discussed. The excellent removal of pollutants depends on the fast generation of reactive oxygen species (SO4•–, •OH, 1O2, and O2•–). The advantages of SACs in AOPs are summarized, and constructive opinions are put forward for the stability and activity of the catalyst. Finally, the opportunities and challenges faced by SACs and its future development direction in the AOPs catalytic field are proposed.

V-Fe concentrate ore was applied to activate peroxydisulfate (PDS) for carbamazepine (CBZ) degradation. The excellent performance of V-Fe concentrate ore was mainly ascribed to the quick electron transfer from surface ≡V(III) and ≡V (IV) to ≡Fe(III) for ≡Fe(II) regeneration, which was confirmed by XPS and XAS analyses. This accelerated ≡Fe(II) regeneration could thus lead to quick formation of HO , SO4 −, O2 − and effective degradation of CBZ. The degradation rate of CBZ could be also expressed by a kinetic model, i.e., −d[CBZ]/dt = (0.83 mM-0.55 min-1(g/L)-0.65) [CBZ]0.29[PDS]1.26[V-Fe]0.65. Combined with the measured intermediates and the results of DFT calculation, CBZ degradation pathway was proposed systematically. Moreover, this catalyst displayed excellent recyclability and general applicability for a broad substrate scope. This study suggests low valent vanadium makes crucial contributions to the high activity of V-Fe-based catalysts, and improves the understanding of electron transfer mechanism between V and Fe in PDS activation process.

The Cd0.9Zn0.1Te crystal growth with low pressure and vertical Bridgman method (LPVB) was numerically simulated and analysed by the simulation software of Comsol Multiphysics. In the process of crystal growth, the influence of variable crucible dropping rate on solid-liquid interface was studied in this paper. The variability of crucible dropping rate was achieved by a specifical furnace temperature distribution function, while the selection and analysis of crucible dropping rate was obtained by the combination of orthogonal experimental design method and regression analysis method. In this paper, the value of relative crystal growth rate was defined, and the influence of variable crucible dropping rate on solid-liquid interface was discussed by comparing these values. The simulation results showed that if the crucible dropping rate was 3.5 mm/h (ν1) in the first stage and 0.6 mm/h (ν2) in the second stage, and the distance (d) between the bottom of crucible and the position of melting point in tempreture field was 0.02 m at the time of dropping rate change, the solid-liquid interface was appreciably convex after 211 hours' growth, and the relative crystal growth rate was 0.45%, which made the solid-liquid interface smooth and kept the crystal grow up spontaneously.

In this paper, the vertical Bridgman method was used to grow In-doped, Al-doped and In-Al codoped CdZnTe crystals. The temperature-dependent Hall effects, X-ray diffraction (XRD), dislocation density were applied to study the energy level of chief defects and the possible existence of compensatory mechanism in the doped CdZnTe crystal. The XRD results showed that lattice distortion existed in the three doped samples, and the lattice distortion in Al-doped crystal was the highest among them. The phenomenon may attribute to the stress caused by the occupation of In and Al atoms at Cd vacancies which make atoms depart from their equilibrium positions. The Hall effect test showed that the n-type In doped CdZnTe samples were estimated to have shallow donors at 15.6 meV below the conduction band, which is associated with [InCd], and the In-Al codoped samples have shallow donors at 15.1 meV below the conduction band, which is associated with [InCd]and [AlCd]. While, for the p-type Al doped CdZnTe sample, shallow acceptors were deduced at 59.9 meV above the valence band, which is considered to be [VCd-2AlCd] (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In-doped CdZnTe (CZT) crystals have been investigated under controlled Te partial pressure. The dependence of the electrical properties on the In dopant concentration under fixed Te partial pressure and the dependence on Te partial pressure under fixed In dopant concentration are presented. The optimized growth parameters, such as Te partial pressure, In dopant concentration, etc., were obtained for preparing In-doped CZT crystal of high resistivity up to 10 Ωcm. In addition, based on an In-doped compensation mechanism in CZT crystals is discussed.

In this paper, the design and fabrication of a capacitive Frisch grid structure for CdZnTe (CZT) detector were investigated. The aging tests were first used to investigate the degradation of the mechanical and electrical characteristics of the CdZnTe detector based on the capacitive frisch grid structure. The effects of the degradation on the performance of CdZnTe detectors were investigated by scanning acoustic microscopy (SAM) test, current-voltage test, and multichannel pulse-height spectrum analysis. In particular, a passivation layer obtained by a two-step passivation processing, combined with a Teflon tape, was used as an insulated layer of the capacitive Frisch grid detector, improving its stability effectively at high voltages. However, further improvements in material and device fabrication (including insulated layer) were required to realize the potential of CZT detectors with the capacitive Frisch grid structure.

The factors influencing the shape of solid-liquid interface during the process of CdZnTe vertical Bridgman growth were investigated in this paper. The relationship between the temperature gradient and the solid-liquid interface parameter ? near the growth interface with different crucible dropping rate was obtained. Here ? represents the solid-liquid interfacial concave-convex extent. If ? is positive, the solid-liquid interface will be convex into solid phase region and if ? is negative, the solid-liquid interface will be convex into liquid phase region. Simulation results show that when the crucible dropping rate (Vp) was rather high (Vp = 50 mm/h), the value of ? dropped greatly with the increase of the solid-liquid interface temperature gradient, and when Vp was low (for example, Vp = 0.1 mm/h), the value of ? declined slowly and had a trend of turning positive value to negative value with the increase of temperature gradient. In particular, when Vp was about 1 mm/h, the solid-liquid interface tended to be flat with the increase of the temperature gradient. Therefore, it might be concluded that when the temperature gradient of solid-liquid interface was greater than 10 K/cm, and Vp was about 1 mm/h, rather flat solid-liquid interface during the process of crystal growth could be obtained. In addition, based on the simulation results, actual crystal growth experiments were implemented. The experimental results are roughly consistent with the simulation results.