Efficient Decomposition of Perfluoroalkyl Substances by Low Concentration Indole: New Insights into the Molecular Mechanisms.

Perfluoroalkyl substances (PFAS) are a class of persistent organic pollutants known as "forever chemicals". Currently, the hydrated electron-based advanced reduction process (ARP) holds promise for the elimination of PFAS. However, the efficiency of ARP is often challenged by an oxygen-rich environment, resulting in the consumption of hydrated electron source materials in exchange for the high PFAS decomposition efficiency. Herein, we developed a ternary system constructed by indole and isopropyl alcohol (IPA), and the addition of IPA significantly enhanced the PFOA degradation and defluorination efficiency in the presence of low-concentration indole (<0.4 mM). Meanwhile, opposite results were obtained with a higher amount of indole (>0.4 mM). Further exploring the molecular mechanism of the reaction system, the addition of IPA played two roles. On one hand, IPA built an anaerobic reaction atmosphere and improved the yield and utilization efficiency of hydrated electrons with a low concentration of indole. On the other hand, IPA suppressed the attraction between indole and PFOA, thus reducing the hydrated electron transfer efficiency, especially with more indole. In general, the indole/PFAS/IPA system significantly improved the PFAS destruction efficiency with a small amount of hydrated electron donors, which provided new insights for development of simple and efficient techniques for the treatment of PFAS-contaminated wastewater.

High-Efficient Visible-Light Photocatalysis Performance and Light-Corrosion Resistance of Ag3PO4 Constructed by double-Z System Composites.

Novel visible-light-driven Ag3PO4/AgBr/AgI photocatalysts were prepared via a simple self-assembly strategy combined with in-situ anion-exchanging process. The photocatalytic activity of Ag3PO4 was significantly improved by constructing double-Z system. Specifically, the obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (DRS). Under visible light irradiation (λ > 420 nm), the Ag3PO4/AgBr/AgI photocatalysts showed much higher photocatalytic activity than bulk Ag3PO4 for the degradation of formaldehyde (HCHO), and 100% HCHO degradation could be obtained within 28 min. The degradation efficiency could be maintained in five cycles. Further electron paramagnetic resonance (ESR) tests demonstrated that both •OH and •O2- generated in the system. This study provides new insights into the fabrication of highly efficient visible-light-driven photocatalysts and facilitates their practical application in emerging environment issues.

Solitaire stents deployment may reduce ischemic events in staged angioplasty for severe carotid stenosis.

OBJECTIVES: Cerebral hyperperfusion syndrome is a fatal complication that can occur after stent angioplasty in patients with severe carotid artery stenosis. Staged angioplasty can prevent cerebral hyperperfusion syndrome. Conventional staged angioplasty consists of small balloon angioplasty in the first stage and carotid artery stenting in the second stage two to four weeks later. Sometimes, antegrade flow during stage 1 could hardly be maintained and stent will be needed. Solitaire stents were used in some patients in our center. This study aimed to examine the safety and effectiveness of Solitaire stents in staged angioplasty. METHODS: A retrospective analysis was performed on patients with severe carotid artery stenosis and preoperative computed tomography perfusion indicating risk of cerebral hyperperfusion syndrome from 2011 to 2018. Small balloon angioplasty (<3 mm in diameter) only was performed in stage 1 (group 1). If antegrade flow during stage 1 is compromised, then a solitaire stent is deployed (group 2). After two to four weeks, cerebral angiography was undertaken in both groups to determine whether to perform stage 2. If the residual stenosis was more than 50%, carotid artery stenting was deployed. Angiographic results, clinical results, and follow-up results were collected and analyzed. RESULTS: Twenty-five patients were included in the study (group 1, n = 19; group 2, n = 6). After stage 1, no patient in group 2 and two patients in group 1 developed new symptomatic cerebral infarction (0.0% vs. 10.5%, p = 1.000). One patient in group 2 and three patients in group 1 (16.7% vs. 15.8%, p = 1.000) developed symptomatic cerebral hyperperfusion syndrome. One patient in group 2 (n = 4) and three patients in group 1 (n = 12) (25% vs. 25%, p = 1.000) developed hyperperfusion phenomenon. Two patients in group 2 and five patients in group 1 (33.3% vs. 26.3%, p = 1.000) developed symptomatic cerebral hyperperfusion syndrome or hyperperfusion phenomenon. One patient in group 1 developed symptomatic cerebral hyperperfusion syndrome and hyperperfusion phenomenon. After stage 2, no new cerebral infarction occurred in both groups. No patient in group 2 (n = 3) and one patient in group 1 (n = 17) developed symptomatic cerebral hyperperfusion syndrome (0.0% vs. 5.9%, p = 1.000). In the combined analysis of both stages, two patients (10.5%) developed new symptomatic cerebral infarction and four patients (21.1%) developed symptomatic cerebral hyperperfusion syndrome in group 1, no patient (0.0%) developed symptomatic cerebral infarction and one patient (16.7%) developed symptomatic cerebral hyperperfusion syndrome in group 2. There was no significant difference in symptomatic cerebral infarction and symptomatic cerebral hyperperfusion syndrome between the two groups (p = 1.000; p = 1.000). Three patients in group 2 and 17 patients in group 1 (50% vs. 89.5%, p = 0.070) underwent stage 2 angioplasty. No cerebral hemorrhage or cerebral infarction occurred in the Solitaire group during the one-year follow-up period. CONCLUSIONS: Solitaire stents deployment may reduce ischemic events in staged angioplasty for severe carotid stenosis.

Effects of cellular prion protein on rapid eye movement sleep deprivation-induced spatial memory impairment.

The effects of cellular prion protein on rapid eye movement sleep deprivation-induced spatial memory impairment were investigated, and the related mechanisms explored. Male C57BL/6 mice were randomly divided into four groups: environment control, sleep deprivation control, sleep-deprived-plasmid adeno-associated virus-green fluorescent protein group, and sleep-deprived-plasmid adeno-associated virus-cellular prion protein-green fluorescent protein group. Overexpression of cellular prion protein was induced by stereotaxic injection of adeno-associated viral plasmids-CAG-enhanced green fluorescent protein-cellular prion protein-Flag (a small label, which can be detected with corresponding tagged antibodies) into the hippocampus. Sleep-deprived mice were allowed no rapid eye movement sleep for 72 hours. Morris water maze was used to assess the effects of cellular prion protein on spatial learning and memory. The expression of amyloid-ß was also investigated in all groups. The sleep-deprived- plasmid adeno-associated virus- cellular prion protein-green fluorescent protein group spent significantly more time in a goal quadrant compared with the sleep-deprived- plasmid adeno-associated virus-green fluorescent protein group. Sleep deprivation resulted in increased amyloid-ß in the hippocampus, which was reversed by the overexpression of hippocampus cellular prion protein. Overexpression of cellular prion protein in the hippocampus rescues rapid eye movement sleep deprivation-induced spatial memory impairment in mice. It is shown that amyloid-ß in the hippocampus might be one of the mechanisms.

Low-Dose Atypical Antipsychotic Risperidone Improves the 5-Year Outcome in Alzheimer's Disease Patients with Sleep Disturbances.

Sleep disturbances (SD) accelerate the progression of Alzheimer's disease (AD) and increase the stress of caregivers. However, the long-term outcome of disturbed nocturnal sleep/wake patterns in AD and on increased stress of spousal caregivers is unclear. This study assessed the 5-year effect of nocturnal SD on the long-term outcome in AD patients. A total of 156 donepezil-treated mild-moderate AD patients (93 AD + SD and 63 AD - SD as a control group) were recruited. The AD + SD patients were formed into 4 subgroups according to the preferences of spousal caregivers for treatment with atypical antipsychotics (0.5-1 mg risperidone, n = 22), non-benzodiazepine hypnotic (5-10 mg zolpidem tartrate, n = 33), melatonin (2.55 mg, n = 9), or no-drug treatment (n = 29). SD were evaluated by polysomnography, sleep scale, and cognitive scale examinations. Moreover, all spousal caregivers of AD patients were assessed using a series of scales, including sleep, anxiety, mood, and treatment attitude scales. Our data showed that nocturnal sleep/wake disturbances were significantly associated with lower 5-year outcomes for AD patients, earlier nursing home placement, and more negative emotions of spousal caregivers. Treatment with low-dose atypical antipsychotic risperidone improved the 5-year outcome in AD + SD patients. In conclusion, low-dose atypical antipsychotic risperidone improves the 5-year outcome in AD patients with SD. Moreover, improvement of nocturnal sleep problems in AD patients will also bring better emotional stability for AD caregivers.

Methotrexate-loaded PEGylated chitosan nanoparticles: synthesis, characterization, and in vitro and in vivo antitumoral activity.

Cancer nanotherapeutics are rapidly progressing and being implemented to solve several limitations of conventional drug delivery systems. In this paper, we report a novel strategy of preparing methotrexate (MTX) nanoparticles based on chitosan (CS) and methoxypoly(ethylene glycol) (mPEG) used as nanocarriers to enhance their targeting and prolong blood circulation. MTX and mPEG-conjugated CS nanoparticles (NPs) were prepared and evaluated for their targeting efficiency and toxicity in vitro and in vivo. The MTX-mPEG-CS NP size determined by dynamic light scattering was 213 ± 2.0 nm with a narrow particle size distribution, and its loading content (LC %) and encapsulation efficiency (EE) were 44.19 ± 0.64% and 87.65 ± 0.79%, respectively. In vitro release behavior of MTX was investigated. In vivo optical imaging in mice proved that MTX was released from particles subsequently and targeted to tumor tissue, showing significantly prolonged retention and specific selectivity. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay obviously indicated that the higher inhibition efficiency of MTX-mPEG-CS NPs meant that much more MTX was transferred into the tumor cells. A significant right-shift in the flow cytometry (FCM) assay demonstrated that MTX-loaded nanoparticles were far superior to a pure drug in the inhibition of growth and proliferation of Hela cells. These results suggest that MTX-mPEG-CS NPs could be a promising targeting anticancer chemotherapeutic agent, especially for cervical carcinoma.

Functional Magnetic Resonance Imaging Study of Apathy in Alzheimer's Disease.

An fMRI study was launched to understand mechanisms of Alzheimer's disease (AD) patients with apathy. The authors reviewed 7 AD patients with apathy and 6 AD patients without apathy. The block method was adopted, and 24 pictures representing positive, negative, and neutral emotional stimuli were viewed when patients were given brain fMRI. Under "sad versus neutral" stimulation, non-apathetic AD patients had increased activity in bilateral amygdala and bilateral fusiform gyrus, whereas apathetic AD patients only had increased activities in bilateral fusiform gyrus. Thus, the amygdala was the possible anatomical structure related to apathy in AD patients.

Synergistic utilization of industrial solid wastes: Extraction of valuable metals from tungsten leaching residue by photovoltaic sawing waste.

Solid waste challenges in both the tungsten and photovoltaic industries present significant barriers to achieving carbon neutrality. This study introduces an innovative strategy for the efficient extraction of valuable metals from hazardous tungsten leaching residue (W-residue) by leveraging photovoltaic silicon kerf waste (SKW) as a silicothermic reducing agent. W-residue contains 26.2% valuable metal oxides (WO3, CoO, Nb2O5, and Ta2O5) and other refractory oxides (SiO2, TiO2, etc.), while micron-sized SKW contains 91.9% Si with a surface oxide layer. The impact of SKW addition on the silicothermic reduction process for valuable metal oxides in W-residue was investigated. Incorporating SKW and Na2CO3 flux enables valuable metal oxides from W-residue to be effectively reduced and enriched as a valuable alloy phase, with unreduced refractory oxides forming a harmless slag phase during the Na2O-SiO2-TiO2 slag refining process. This process achieved an overall recovery yield of valuable metals of 91.7%, with individual recovery yields of W, Co, and Nb exceeding 90% with the addition of 8 wt.% SKW. This innovative approach not only achieves high-value recovery from W-residue and utilization of SKW but also minimizes environmental impact through an efficient and eco-friendly recycling pathway. The strategy contributes significantly to the establishment of a resource-efficient circular economy, wherein the recovered high-value alloy phase return to the tungsten supply chain, and the harmless slag phase become raw materials for microcrystalline glass production.

Construction of porous Si/Ag@C anode for lithium-ion battery by recycling volatile deposition waste derived from refining silicon.

Owing to the rapid advancement of the photovoltaic industry, a lot of photovoltaic (PV) silicon waste will be generated. Thus, the recycling and reuse of waste silicon have become particularly important, both for environmental remediation and economic benefits. In this work, a special structure of porous Si nanoparticles embedded nano-Ag and coated carbon layer (P-SiNPs/Ag@C) was produced by silver-assisted chemical etching (Ag-ACE) the deposited silicon waste. The special porous structure and carbon layer coating can effectively address the volume expansion issues during charge/discharge. The intercalated Ag nanoparticles greatly reduced the transfer impedance and enhanced the electrical conductivity of the anode material. As a result, the novel-designed P-SiNPs/Ag@C anode can maintain a prominent reversible capacity (1521 mAh·g-1 at 0.2 A g-1 after 50 cycles) and outstanding rate performance (1099 mAh·g-1 at 2 A g-1). When the current density at 1 A g-1, the specific capacity still maintains at 706 mAh·g-1 over 300 cycles. The superiority of the prepared P-SiNPs/Ag@C structures was further confirmed by Comsol Multiphysics software. Impressively, the synthesis route provides a novel avenue for value-added utilization of residual silicon waste resources from EB refining silicon and the preparation of high-performance lithium battery silicon-based anode.

Three-Dimensional Porous Si@SiOx/Ag/CN Anode Derived from Deposition Silicon Waste toward High-Performance Li-Ion Batteries.

The application of photovoltaic (PV) solid waste to the field of lithium-ion batteries is deemed to be an effective solution for waste disposal, which can not only solve the problem of environmental pollution but also avoid the loss of secondary resources. Herein, based on the volatile deposited waste produced by electron beam refining polysilicon, a simple and environmentally friendly method was designed to synthesize P-Si@SiOx/Ag/CN as an anode material for lithium-ion batteries. Remarkably, the presence of silver and the formation of a carbon-nitrogen network can enhance the electrical conductivity of the composite and boost the transport efficiency of lithium ions. Furthermore, the porous Si@SiOx structure is generated by silver-assisted chemical etching (Ag-ACE), and the carbon-nitrogen grid architecture is formed after lyophilization with NaCl as a template, which can jointly provide sufficient buffer space for the volume change of silicon during lithiation/delithiation. Benefitting from these advantages, the P-Si@SiOx/Ag/CN anode exhibits outstanding cycling performance with 759 mA h g-1 over 300 cycles at 0.5 A g-1. Meanwhile, the lithium-ion batteries employing the P-Si@SiOx/Ag/CN anodes present a superior rate capability of 950 mA h g-1 at 2 A g-1 and retain a high reversible specific capacity of 956 mA h g-1 at 1 A g-1 after 50 cycles. This work opens up a new economic strategy for the fabrication of high-performance silicon anodes and affords a promising avenue for the recycling of PV silicon waste.

Preparation of Al-Si alloy from silicon cutting waste: Enabling oxide surface removing and silicon utilization improving via vacuum sintering.

Environmentally harmful silicon cutting waste (SCW) generated during the production of silicon solar cells possesses a high reuse value. However, the presence of oxide surface and impurities restrict the Si-cores reuse. Herein, inspired by the structure and composition of SCW, designed a combined process consisting of vacuum sintering and alloying to reuse SCW into Al-Si alloy at a low cost. Vacuum sintering promotes the reduction of the oxide surface by Si-core. Oxygen content was decreased by 92.54 %, demonstrating the successful removal of the oxide surface. The discharge of reduction products contributes to the densification, and the Si-core has converged into dense Vac-ceramic (Si block), rendering a relative density of 96.17 %. More importantly, during the alloying process, the formation of Vac-ceramic dredges the mass transfer pathway from Si-core to Al melt. As a result, the Si utilization rate increased about seven times compared with the direct reuse of pristine SCW. Compared with commercial Al-Si alloys, the Al-Si alloys prepared by reusing silicon cutting waste in this work have satisfactory mechanical properties. The method has the prominent advantages of being protective-atmosphere-free, additive-free, and scalability, and may be a promising candidate for the silicon cutting waste purifying and reusing field.

Recycling of silicon from waste PV diamond wire sawing silicon powders: A strategy of Na2CO3-assisted pressure-less sintering and acid leaching.

Recycling diamond wire sawing silicon powders (DWSSP) from photovoltaic (PV) silicon wafers production has become an urgent problem. The challenge of recovery is the surface oxidation and contamination of the ultra-fine powder with impurities during the sawing and collection process. In this study, a clean recovery strategy of Na2CO3-assisted sintering and acid leaching was proposed. Due to the Al contamination from the perlite filter aid, the introduced Na2CO3 sintering aid can react with the SiO2 shell of DWSSP to form a slag phase with accumulated impurity Al during the pressure-less sintering process. Meanwhile, the evaporation of CO2 contributed to the formation of ring-like pores surrounded by a slag phase, which can be easily removed by acid leaching. When 15 % Na2CO3 was added, the content of impurity Al in DWSSP could be reduced to 0.07 ppm with a removal rate of 99.9 % after acid leaching. The mechanism suggested that the addition of Na2CO3 can trigger the liquid phase sintering (LPS) process of the powders, and the cohesive force and liquid pressures difference generated during the process facilitated the transportation of impurity Al from the SiO2 shell of DWSSP to the formed liquid slag phase. The efficient silicon recovery and impurity removal of this strategy demonstrated its potential for solid waste resource utilization in the PV industry.

Photochemical degradation of perfluorooctanoic acid under UV irradiation in the presence of Fe (III)-saturated montmorillonite.

Perfluorooctanoic acid (PFOA) has attracted worldwide attention owing to its widespread distribution and potential ecological risks. Developing low-cost, green-chemical and highly efficient treatment approaches is significant for treating PFOA caused environmental issues. Herein, we propose a feasible PFOA degradation strategy under UV irradiation by adding Fe (III)-saturated montmorillonite (Fe-MMT), and the Fe-MMT could be regenerated after reaction. In our system consisting of 1 g L-1 Fe-MMT and 24 µM PFOA, nearly 90 % initial PFOA could be decomposed within 48 h. The enhanced PFOA decomposition could be explained by the ligand-to-metal charge transfer mechanism based on the generated reactive oxygen species (ROSs) and the transformation of iron species in the MMT layers. Moreover, the special PFOA degradation pathway was revealed according to the intermediate identification and the density functional theory calculation. Further experiments demonstrated that even in the presence of co-existing natural organic natter (NOM) and inorganic ions, efficient PFOA removal could still be obtained in UV/Fe-MMT system. This study offers a green-chemical strategy for PFOA removal from contaminated waters.

Dissolved black carbon incorporating with ferric minerals promoted photo-Fenton-like degradation of triclosan in acidic conditions.

Dissolved black carbon (DBC) has been recognized as an important organic matter that influences the photochemical processes of organic pollutants. The excited triplet state (3DBC*) of DBC usually exhibits activity in neutral and basic aqueous conditions, rather than in acidic conditions. In this study, we found the crop (wheat, rice, maize) straw sourced DBC can substantially enhance the photodegradation of triclosan in relatively acidic conditions, and in the presence of ferric minerals (ferrihydrite and lepidocrocite), when exposed to simulated sunlight irradiation. This should be ascribed to the rapid non-reductive dissolution of ferric minerals by DBC, which leads to the generation of abundant hydrogen peroxides (H2O2) and hydroxyl radicals (•OH) through photo Fenton-like reactions. •OH is the dominant reactive species that leads to triclosan degradation in acidic conditions. Otherwise, triclosan itself is resistant to direct photolysis at pH < 5.0. The triplet state (3DBC*) plays a critical role in accelerating the Fe3+/Fe2+ cycling, which further promotes •OH generation. This study provides a new perspective on the role of DBC in surface water or mineral-water interfaces with acidic conditions and adds a more comprehensive understanding about the environmental implications of the DBC-ferric mineral system in sunlit surface water.

Enhanced photodegradation of tylosin in the presence of natural montmorillonite: Synergistic effects of adsorption and surface hydroxyl radicals.

Tylosin (TYL) is a ubiquitous macrolide antibiotic which has been frequently detected in natural aqueous environment. Montmorillonite (MMT), a major component of natural suspended particles, plays essential roles in the transportation and transformation processes of various organic contaminants. This study systematically investigated the photodegradation behavior and mechanism of TYL in MMT suspensions under simulated sunlight irradiation. In the existence of 0.1 g L-1 Na-MMT, >80.8 % TYL was degraded after 8 h irradiation, which was significantly higher than that in the absence of MMT (42.5 %). Further mechanistic studies suggested that the synergistic effects including the formation of surface complex and the generation of surface hydroxyl radicals play essential roles in the accelerated TYL phototransformation. Meanwhile, other factors like exchangeable cations of MMTs, pH and ionic strength could also strongly influence the TYL photodegradation. The probable degradation pathways of TYL in MMT suspension was further proposed based on the detected intermediates and DFT calculations. Photobacterium phospherium T3 bioluminescent assay revealed that the photodegradation products of TYL have a lower acute toxicity than bulk TYL, especially in the presence of MMT. This study provides new insights for the photodegradation pathways of organic contaminants in aqueous environments, which is of great importance for assessing the fate and risk of emerging pollutants in natural surface water bodies.

Retraction: In situ Raman investigation of the phase transition of NaVO2F2 under variable temperature conditions.

[This retracts the article DOI: 10.1039/D1RA02827H.].

Identification of miRNA-mRNA Pairs in the Alzheimer's Disease Expression Profile and Explore the Effect of miR-26a-5p/PTGS2 on Amyloid-ß Induced Neurotoxicity in Alzheimer's Disease Cell Model.

Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common type of dementia. MicroRNAs (miRNAs) have been extensively studied in many diseases, including AD. To identify the AD-specific differentially expressed miRNAs and mRNAs, we used bioinformatics analysis to study candidate miRNA-mRNA pairs involved in the pathogenesis of AD. These miRNA-mRNAs may serve as promising biomarkers for early diagnosis or targeted therapy of AD patients. In this study, based on the AD mRNA and miRNA expression profile data in Gene Expression Omnibus (GEO), through differential expression analysis, functional annotation and enrichment analysis, weighted gene co-expression network analysis, miRNA-mRNA regulatory network, protein-protein interaction network, receiver operator characteristic and Least absolute shrinkage and selection operator (LASSO) regression and other analysis, we screened the key miRNA-mRNA in the progress of AD: miR-26a-5p/PTGS2. Dual-luciferase and qPCR experiments confirmed that PTGS2 is a direct target gene of miR-26a-5p. The expression of miR-26a-5p in the peripheral blood of AD patients and AD model cells (SH-SY5Y cells treated with Aß25-35) was up-regulated, and the expression of PTGS2 was down-regulated. Functional gain -loss experiments confirmed that PTGS2 protects AD model cells from damage by inhibiting proliferation and migration. However, the expression of miR-26a-5p promotes the proliferation of AD model cells. It is further found that PTGS2 is involved in the regulation of miR-26a-5p and can reverse the effect of miR-26a-5p on the proliferation of AD model cells. In addition, through network pharmacology, qPCR and CCK-8, we found that baicalein may affect the progression of AD by regulating the expression of PTGS2. Therefore, PTGS2 can be used as a target for AD research, and miR-26a-5p/PTGS2 can be used as an axis of action to study the pathogenesis of AD.

Snow-like BiVO4 with rich oxygen defects for efficient visible light photocatalytic degradation of ciprofloxacin.

The overuse of ciprofloxacin (CIP), causing serious environment pollution, has drawn great attentions. To provide alternative solution to this problem, we synthesized a snow-like BiVO4 with rich oxygen vacancy by adjusting the amounts of cetyltrimethyl ammonia bromide (CTAB) surfactant. Various characterizations were performed to investigate the morphology and surface properties of the synthesized BiVO4. Interestingly, both the morphology and the amount of oxygen vacancy were related to the concentration of additional CTAB, and the most oxygen vacancies were generated when specific amount of CTAB (molar ratio of CTAB to Bi3+ of 0.2) was introduced. Photoluminescence and photoelectrochemical tests demonstrated that the presence of oxygen vacancy significantly enhanced the separation efficiency of photo-generated carriers in BiVO4. Subsequently, CIP photodegradation was significantly enhanced in the presence of snow-like BiVO4. Both quenching experiments and EPR tests demonstrated that photogenerated holes and •O2- were the main active species contributing to CIP degradation. Furthermore, CIP transformation pathway was proposed based on the identified transformation products. Our study developed a novel method to synthesize a BiVO4 material with snow-like morphology and abundant oxygen vacancy by simply varying the amount of surfactant. This study would shed light on designing the next generation photocatalyst with the assistant of surfactant to control the surface properties.

Recycling silicon kerf waste: Use cryolite to digest the surface oxide layer and intensify the removal of impurity boron.

The surface oxide layer (SiO2 layer) is still one of the main limitations of the recovery and purification of silicon kerf waste (SKW). Herein, to recycle SKW as the low-boron silicon ingot, an effective combination strategy that digests the surface oxide layer by pretreatment and then removes impurity boron by slag treatment is proposed. In the pretreatment part, the surface oxide layer of SKW was successfully digested into a liquid phase after mixing 10.5 wt% cryolite and sintering at 1400 °C, and the obtained SKW-ceramic has a dense structure. Moreover, when holding at 1400 °C for 2 h, the boron concentration in SKW-ceramic was decreased to 5.75 ppmw, and the removal rate reaches 14.18%. In the slag treatment part, CaO and SiO2 are selected as slag agents. The CaO/SiO2 mass ratio and reaction temperature were determined to be 2 and 1600 °C based on thermodynamic simulation. Besides, Na2O formed due to the dissociation of cryolite, which can enhance the oxygen ion activity and boron-absorbing capacity of the slag. The experimental result exhibited that the boron removal efficiency reached 86.56%. The simplicity and scalability of this strategy provide a better alternative for the recovery of SKW.

In situ Raman investigation of the phase transition of NaVO2F2 under variable temperature conditions.

In this study, the phase transition of NaVO2F2 was measured at different temperatures via in situ Raman spectroscopy. The NaVO2F2 compounds were synthesized by a hydrothermal method and were identified to be monoclinic with the P21/c space group at room temperature by XRD. Accordingly, the variations of Raman shifts and intensities of the characteristic peaks for NaVO2F2 associated with temperature were obtained and investigated. It was confirmed that NaVO2F2 had three types of phase transitions, which occurred in the temperature region from 78 K to 573 K. Further, the results indicate that transition from a low-temperature phase (I) to another low-temperature phase (II), low-temperature phase (II) to P21/c phase and P21/c phase to P21/m phase occurred near the three temperature points of 93 K, 233 K, and 453 K, respectively, during the heating process. Therefore, a novel characterization method was provided for further research on the phase transition theory and performance of vanadate compounds.