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Zirconium based alloys, as refractory metallic materials, can be fabricated into brittle zirconium hydride by hydrogen charging and can then be used as neutron moderators in the nuclear industry. In this study, the fracture toughness of bulk e zirconium hydride was attempted to be estimated by means of Vickers microhardness indentation. Several representative semi-empirical formulas based on Palmqvist and half-penny crack models were adopted, and relevant parameters including Young’s modulus, Vickers hardness, indentation dimension, and crack length were respectively determined. It was observed that cracks began to nucleate at impression corners and peripheries when the load was higher than 500 gf. Crack length at 1000 gf was measured and used to estimate the fracture toughness. The results showed similar values to previous reports obtained from conventional experimental means, indicating that Vickers microhardness indentation is an available method for estimating the fracture toughness of e zirconium hydride.

In the present work, the behavior of recovery and recrystallization have been investigated in -oriented Mo-3Nb single crystals cold deformed by uniaxial compression. The macroscopic deformation characteristics and subsequent annealed microstructure evolution of the compressed Mo-3Nb single crystals were carried out by stereomicroscope and electron backscatter diffraction, respectively. Annealed grain boundary misorientation analysis shows Mo-3Nb single crystals no longer keep a monocrystal structure when the compressive strain exceeds 30%. The proportion of high-angle grain boundaries after annealing for Mo-3Nb single crystal with cold compression at high strain rate is larger than that at low strain rate, suggesting that increasing the strain rate can promote the recovery and recrystallization behavior. To elucidate the evolution process of substructure in the recovery and recrystallization, TEM analyses were performed. The annealed dislocation density is reduced and rearranged compared to the cold-compressed state. With the increase of compressive strain, the annealing sub-structure changes from recovery to recrystallization. The recovery process is primarily polygonization, and the mechanism of recrystallization nucleation is through the coalescence of sub-grains.

A novel magnetic Fe3O4@SiO2@Bi2O2CO3/rGO composite comprising of uniform core-shell-structured Fe3O4@SiO2@Bi2O2CO3 microspheres mounted on reduced graphene oxide (rGO) sheets was successfully fabricated by using a facile hydrothermal method. The adsorption–desorption isotherm of Fe3O4@SiO2@Bi2O2CO3/rGO belonged to type IV with an H4-type hysteresis loop. The specific surface areas and magnetization saturation value (Ms) of Fe3O4@SiO2@Bi2O2CO3/rGO (x = 0.15 g) were 102.12 m2/g and 25.4 emu/g, respectively. Fe3O4@SiO2@Bi2O2CO3/rGO (x = 0.15 g) exhibited remarkable photocatalytic degradation activity and mineralization effect for MO and decolorization performance for the mixed solution of MO, Rh B, and MB. MO degradation by Fe3O4@SiO2@Bi2O2CO3/rGO conformed to a first-order kinetic reaction, and the corresponding kapp value was 0.05553 min−1. A suitable amount of rGO in Fe3O4@SiO2@Bi2O2CO3/rGO could decrease the energy band gap, inhibit the recombination of photo-induced electron/hole (e−/h+) pair, and broaden and enhance the response of the catalyst to visible light, thereby enhancing the visible-light catalytic degradation of organic dyes. The active species produced in the photocatalysis included •O2−, •OH, and h+, with •O2− being the dominant active species. The as-prepared photocatalyst also showed excellent magnetic separation performance and stability. Results show that the as-prepared Fe3O4@SiO2@Bi2O2CO3/rGO composite is a promising photocatalyst with considerable application potential in organic dyes removal.

Objective: To determine the prevalence of sensitivity to common inhaled and food allergens among children with allergic rhinitis (AR) in Changzhou in eastern China and provide a basis for clinical evaluation of pediatric allergic status and prevention strategies for allergen avoidance.Methods: A total of 1248 children with AR were enrolled at the Third People's Hospital of Changzhou between January 2018 and December 2019. The serum-specific immunoglobulin E (sIgE) to 19 kinds of inhaled and food allergens and serum total IgE were detected with the AllergyScreen test (Mediwiss Analytic GmbH, Moers, Germany). All participants had a positive reaction to at least one allergen in the test.Results: Among the patients, 818 (65.54%) were male and 430 (34.46%) were female, with 81 (6.50%) aged 1–3 yr, 501 (40.14%) aged 4–7 yr, and 666 (53.36%) aged 8–14 yr. The positivity rate of inhaled allergens was 80.05% (n = 999), while the positivity rate of food allergens was 66.19% (n = 826). The most common inhaled allergens were Dermatophagoides pteronyssinus (65.38%), mold mix (25.56%), house dust (20.67%), and dog hair dander (13.94%), and the most common food allergens were cow's milk (30.31%), cashew nut (27.9%), egg (22.68%), and beef (12.98%). With an increase in age, the inhaled allergen positivity rate increased, while the food allergen positivity rate decreased. Total IgE levels were higher in the groups with older children.Conclusions: Dermatophagoides pteronyssinus was the most common sensitizing allergen in pediatric patients with AR in Changzhou. Several other inhaled and food allergens were also common. We observed that multiple allergenic factors play an important role in the occurrence and development of AR.

A novel magnetic Fe3O4@SiO2@BiFeO3/rGO composite was successfully fabricated via a facile hydrothermal method. This composite consisted of flower-like core-shell structured Fe3O4@SiO2@BiFeO3 microspheres mounting on reduced graphene oxide (rGO) nanosheets. The specific surface areas, magnetization saturation value (Ms), and band gap energy (Eg) of Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) were 139.26 m2/g, 20.3 emu/g, and 1.91 eV, respectively. Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) exhibited remarkable ability to photocatalytically degrade ciprofloxacin (CIP), tetracycline hydrochloride (TC-H), methylene blue (MB), and decolorize a mixed solution of MB, methyl orange (MO), and rhodamine B (Rh B); CIP, TC-H, and MB degradation by Fe3O4@SiO2@BiFeO3/rGO conformed to a first-order kinetic reaction, and the corresponding kapp values by Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) were 0.04211, 0.02792, and 0.05967 min−1, respectively. Excellent magnetic separation performance, recyclability, and stability were also observed. A suitable amount of rGO to the as-prepared photocatalyst could decrease the Eg, accelerate the transfer of photogenerated electrons (e−), suppress the recombination of photo-generated e−–hole (h+) pairs, and enhance the visible-light response of the catalyst. The •OH is the dominant active species during photocatalysis. This work suggests a promising strategy to synthesize photocatalysts with enhanced ability to catalytically degrade organic pollutant under visible light and excellent recyclability.

Influence mechanism of sulfide ions (S2-) during manganese electrodeposition from sulphate electrolyte was investigated. Under the experimental conditions, S2- ion concentration and electrolyte pH represented significant multiple effects on the cathode current efficiency. Scanning electron microscope (SEM) indicated that electrodeposition manganese layer (EML) became refinement as S2- ion concentration was increased. X-ray Diffraction (XRD) displayed that S2- ion had negligible influence on the preferred orientation of the crystalline layer of the EML. S2- ion had no influence on the chemical composition of EML. S2- ion could improve the corrosion resistance of EML. The interaction mechanism of S2- ion with manganese electrodeposition was systematically explored by analysing E-pH diagram, cyclic voltammetry curve, cathode polarization curve and electrochemical impedance method.

The coagulation-dissolved air flotation for removal of sodium oleate (NaOL) from synthetic manganese leaching solution was focused in this study. It indicates that partially hydrolyzed polyacrylamide (HPAM), NaOL dosage and pH have a multiple effect on the removal efficiency of NaOL. The results represents a significant removal efficiency of 97.6% NaOL was achieved under the optimal conditions of coagulation-dissolved air flotation by dosage of 20 mg/L HPAM and 30 mg/L NaOL, pH 8.0. Solution pH has a significant effect on the distribution of oleate species and Mn2+ species. The addition of HPAM facilitates the formation of OL− micelle and the decrease of critical micelle concentration (CMC). Oleate species primarily exist, containing Mn(OL)2(s), OL− and HOL(aq). HPAM could cause the Zeta potential of NaOL to shift negatively. HPAM could decrease CMC of NaOL and lead to a transition from three dimensional network structure to lamellar structure. NaOL can be removed by coagulation-dissolved air flotation through the adsorption and bridge effect of HPAM chains on the floating bubble surface.

A two-component material (Fe3O4@CaSiO3) with an Fe3O4 magnetite core and layered porous CaSiO3 shell from calcium nitrate and sodium silicate was synthesized by precipitation. The structure, morphology, magnetic properties, and composition of the Fe3O4@CaSiO3 composite were characterized in detail, and its adsorption performance, adsorption kinetics, and recyclability for Cu2+, Ni2+, and Cr3+ adsorption were studied. The Fe3O4@CaSiO3 composite has a 2D core–layer architecture with a cotton-like morphology, specific surface area of 41.56 m2/g, pore size of 16 nm, and pore volume of 0.25 cm3/g. The measured magnetization saturation values of the magnetic composite were 57.1 emu/g. Data of the adsorption of Cu2+, Ni2+, and Cr3+ by Fe3O4@CaSiO3 fitted the Redlich–Peterson and pseudo-second-order models well, and all adsorption processes reached equilibrium within 150 min. The maximum adsorption capacities of Fe3O4@CaSiO3 toward Cu2+, Ni2+, and Cr3+ were 427.10, 391.59, and 371.39 mg/g at an initial concentration of 225 mg/L and a temperature of 293 K according to the fitted curve with the Redlich–Peterson model, respectively. All adsorption were spontaneous endothermic processes featuring an entropy increase, including physisorption, chemisorption, and ion exchange; among these process, chemisorption was the primary mechanism. Fe3O4@CaSiO3 exhibited excellent adsorption, regeneration, and magnetic separation performance, thereby demonstrating its potential applicability to removing heavy metal ions.

The adsorption characteristic and mechanism of poly(N1,N1,N3,N3-tetraallylpropane-1,3-diaminium chloride) (PTAPDAC) toward Cr(VI) ions were systematically investigated. Results showed that the remo...

Solvent extraction of phosphoric acid from wet process phosphoric acid produced by decomposing low grade phosphate with hydrochloric acid was investigated by the mixture of n-butanol (nBA) and isopropyl ether (iPE). The experimental results show that the mixture has good performance on P2O5 extraction and Ca2+ purification from HCl-route wet-process phosphoric acid. Optimization of extraction process shows that nBA has good performance for H3PO4 separation at the condition of 5:1 O/A phase ratio, 293 K extraction temperature, 9:1 VB/VE ratio and 15 min extraction time. Based on the Van't Hoff equation, the enthalpy changes of P2O5 extraction was calculated to be −16.41 kJ.mol−1. The results from liquid-liquid mass transfer show three stages can achieved about 90 wt% P2O5 extraction regardless of the countercurrent and cocurrent extraction. And the relation of total extraction percent and cross-flow extraction stages for all tested components were summarized. Moreover, the extraction mechanism between H3PO4 and nBA was discussed by researching the extraction equilibrium under different conditions. The result showed that phosphoric acid was extracted in the form of H3PO4·nBA, H3PO4·2 nBA and H3PO4·3 nBA complexes. Stripping operations using Deionized water as a extractant for phosphoric acid was also investigated at different conditions.

The flotation performance and hydrophobic mechanism of O-ethyl-N-benzoyl thionocarbamate (EBZTC) on chalcopyrite were first estimated by single flotation experiments, batch adsorption experiments, contact angle measurements, DFT calculation and FTIR analysis. Single flotation experiments illustrated that a flotation recovery of 96.7% was achieved to chalcopyrite when EBZTC was used compared to 90% with SIBX at pH 6.5. Adsorption experiments indicated that the adsorption process of EBZTC on chalcopyrite surface was an exothermic monolayer chemisorption process. Hydrophobic mechanism demonstrated that EBZTC chemisorbed onto the chalcopyrite surface through the chemical reactions of C O and C S groups to the copper species with the formation of C O Cu and C S Cu bonds, which resulted in the coverage of the hydrophobic groups of EBZTC onto the chalcopyrite surface to enhance its hydrophobicity.

Microstructure evolution and mechanical properties, i.e., Young's modulus, hardness and yield strength variations were investigated for hydrogenated Zircaloy-4 tubes during thermal decomposition process of precipitated hydrides. Firstly, the embedded δ-hydrides were synthesized through hydrochemical method in autoclave. Then the dehydrogenation temperature and corresponding activation energy were detected via DSC as 832–869 K and 185.4 KJ/mol when heated up to 1273 K which simulated the loss of coolant accident (LOCA) temperature. Finally, nanoindentation technique was performed on samples in as-received state, hydrides, surrounding matrix, post-hydriding samples after 869 and 1273 K anneal to determine the mechanical properties. The Young's modulus and hardness calculation were carried out by Oliver-Pharr theory and corrections were implemented by P-U model meanwhile the yield strength was figured out using empirical equations. The results showed that the modulus, hardness and yield strength of δ-hydrides were the largest of all. Mechanical properties of as-received material were highly similar to the surrounding matrix. Different from 869 K anneal, the microstructure changed from equiaxed grain to Basket-weave Widmanstatten after 1273 K anneal while corresponding modulus, hardness and yield strength elevated to a comparable level with δ-hydrides due to the increase of oxygen content.

Flotation collectors with strong collecting ability and superior selectivity have important application prospects for recovering complex and refractory copper sulfide resources. Herein, a novel surfactant of N-benzoyl-N’,N’-diethyl thiourea (BDETU) with C O and C S groups is synthesized for separation of chalcopyrite and pyrite. The flotation performance and adsorption mechanism of BDETU to chalcopyrite and pyrite were evaluated by flotation experimental, adsorption experimental, contact angle measurements, UV–vis spectroscopy, as well as FTIR analyses and DFT calculation. By comparing the flotation performances with the traditional flotation collector of O-isopropyl-N-ethyl thionocarbamate (IPETC), it becomes evident that BDETU exhibit stronger collecting ability and excellent selectivity for chalcopyrite against pyrite. These results might be attributed to the facts that BDETU can selectively adsorb on the surface of chalcopyrite and strengthen its surface hydrophobicity, while the hydrophobicity of pyrite surface is not improved with the weak adsorption of BDETU on its surface. The analyses of adsorption mechanism reveal that BDETU is chemically adsorbed on the surface of chalcopyrite by the reactions of the functional groups (C O and C S) to the copper species with the formation of C O Cu and C S Cu structures.

In view of reducing contaminant and recovery arsenic and antimony, a novel technology was proposed to recover arsenic and antimony from arsenic-rich copper smelter dust comprehensively. The technique route includes three stages: arsenic and antimony trioxides were leached from the copper smelter dust with hydrochloric acid; trivalent arsenic ions (As3+) were then reduced to less toxic simple arsenic (As) by sodium hypophosphate (NaH2PO2) and recovered; and stepwise recovery of antimony by SbCl3 was achieved by the continuous distillation technique. The results indicates that the leaching efficiency of As and Sb was over 97.5% and 96.8% under conditions of initial 4.0 mol/L HCl, liquid-solid ratio (L/S) of 6:1, leaching temperature of 363 K and time of 2 h. Over 92.5% arsenic was recovered by NaH2PO2 reduction under the suitable conditions: 363 K, 1.5 h and 2.0 times addition of NaH2PO2. The recovery rate of Sb is more than 97.53% at 393 K. The distillation temperature of SbCl3 was optimized between 463 K and 473 K. The corresponding mechanisms of the leaching and recovering of arsenic and antimony were systematically investigated and confirmed by E-pH diagram, thermodynamic calculation, arsenic speciation, composition analysis and XRD characterization.

Novel magnetic core-shell structured Fe3O4@SiO2@BiFeO3–sepiolite microspheres were fabricated via a facile hydrothermal method. The as-prepared microspheres comprised a Fe3O4@SiO2 magnetic core with a strong response to external fields and a porous BiFeO3/sepiolite composite functional layer. The specific surface area, magnetization saturation value (Ms), and band gap energy (Eg) of Fe3O4@SiO2@BiFeO3–sepiolite (x = 0.4 g) were 126.68 m2/g, 18.2 emu/g, and 2.09 eV, respectively. A suitable amount of sepiolite in Fe3O4@SiO2@BiFeO3–sepiolite could improve the microstructure of the photocatalyst through the interface effect between the sepiolite and the formed BiFeO3, which can enlarge the specific surface area and thus increase the absorption of light and the adsorption of pollutants, decrease the Eg of the as-prepared photocatalyst, and improve the separation and inhibit the recombination of photogenic electron and hole (e−/h+) pairs, thereby expediting the photocatalytic degradation of pollutants. The as-obtained Fe3O4@SiO2@BiFeO3–sepiolite (x = 0.4 g) exhibited a remarkable photocatalytic degradation performance for ciprofloxacin (CIP), tetracycline hydrochloride (TC-H), and methylene blue (MB) and an excellent decolorization for the mixed solution of methyl orange (MO), rhodamine B (Rh B), and MB under visible-light irradiation. In addition, the as-obtained photocatalyst demonstrated excellent magnetic separation performance, recyclability, and stability. The active species produced during the photocatalysis included OH, O2−, and h+, with OH being the dominant active species. Such a well-structured core-shell photocatalyst has remarkable potential for numerous applications in treating organic wastewater.

A novel magnetic core–shell architecture Fe3O4@Sio2@Bi2O2CO3–sepiolite composite was successfully fabricated by coating a layer of Bi2O2CO3–sepiolite mixture onto Fe3O4@Sio2 cores through a facile hydrothermal method. The photodegradation rates of ciprofloxacin (CIP) and tetracycline hydrochloride (TC-H) were 92.1% and 100%, respectively. A suitable amount of sepiolite in Fe3O4@Sio2@Bi2O2CO3–sepiolite can enlarge the specific surface area, promote the formation of an excellent photocatalyst structure, and generate a strong interfaces effect between the sepiolite and Fe3O4@Sio2@Bi2O2CO3. This condition endowed the as-prepared photocatalyst with high light harvesting capability and abundant active reaction sites. It also boosted the separation of photogenic e − /h + pairs. Moreover, this condition inhibited the recombination of e − /h + pairs and decreased the energy band gap, thereby enhancing the visible light catalytic degradation of antibiotics. The active species produced during photocatalysis included h + and •O 2 − , with h + as the dominant active species. The as-prepared photocatalyst exhibited excellent photocatalytic degradation activity, magnetic separation performance, recyclability, and stability.

The influences of tetraborate anions on manganese electrodeposition in an anion-exchange membrane electrolysis reactor were investigated. The experimental results of manganese electrodeposition indicate that a certain amount of tetraborate anions can increase cathode current efficiency and initial pH 7.0–8.0 is suitable for high cathode current efficiency. X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis show the nanocrystalline structure and impact morphology of electrodeposited manganese. The purity of electrodeposited manganese is above 99.88 %. The tests of tetraborate anions on buffer capacity (β) and pH value of the electrolyte near the cathode surface confirm that tetraborate anions facilitate manganese electrodeposition. Tetraborate anions can improve concentration polarization of Mn2+ ions and then increase the overpotential of hydrogen evolution reaction. Therefore, ammonium tetraborate can reduce the hydrogen embrittlement, pore, and pitting negative effect on electrodeposit surface, to improve the corrosion resistance of electrodeposited manganese. After tetraborate anions being added in electrolyte, weight loss measurement indicates that the corrosion resistance of electrodeposited manganese is improved. Electrochemical measurements testify that corrosion resistance of electrodeposited manganese containing tetraborate anions in electrolyte is reflected by less negative corrosion potential and higher impedance.

The leaching kinetics of reductive leaching of manganese from manganese dioxide ores (MDO) in dilute sulfuric acid in the presence of Phytolacca americana powder (PAP) was investigated. The effects of stirring speed, leaching temperature and leaching time, particle size, weight ratio of PAP to MDO ( C W ) and sulfuric acid concentration ( C H ) on the leaching efficiency of manganese were studied. The leaching efficiency of manganese based on the shrinking core model was found to be controlled by diffusion through the ash/inert layer composed of the associated minerals. The apparent activation energy is 15.18 kJ mol −1 . The experimental results indicate reaction order of 0.797 for C H and 1.25 for C W . The overall leaching efficiency equations for MDO dissolution reaction with PAP in dilute sulfuric acid were proposed by a semi-empirical model.

The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode current efficiency and initial pH 7.0–8.0 is the optimized pH for high cathode current efficiency. The analyses of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate the compact morphology and nanocrystalline structure of electrodeposits. X-ray photoelectron spectrometry (XPS) analysis shows that the elements of Mn, Si and O exist in the deposit. The solution chemistry calculations of sulfate electrolyte and sodium silicate solution indicate that species of Mn 2+ , MnSO 4 , Mn(SO 4 )2–2, Mn 2+ , MnSiO 3 , Mn(NH 3 ) 2+ , SiO 3 2– and HSiO 3 − are the main active species during the process of manganese electrodeposition. The reaction trend between Mn 2+ and Si-containing ions is confirmed by the thermodynamic analysis. In addition, polarization curve tests confirm that sodium silicate can increase the overpotential of hydrogen evolution reaction, and then indirectly improve the cathode current efficiency.

The influence of sodium oleate (NaOL) on manganese electrodeposition from sulfate solution was systematically investigated in terms of cathode current efficiency, solution chemistry calculation and thermodynamic analysis, polarization curves and Fourier transform infrared spectroscopy (FT-IR) analysis. The experimental results show that NaOL concentration and pH present a multiple effect on cathode current efficiency. According to the solution chemistry calculations of sulfate electrolyte and NaOL, it is found that MnSO4, Mn(SO4)22 −, Mn2 +, Mn(NH3)2 +, and OL− and (OL)22 − are the main active species, respectively. The reaction trend between OL− and Mn2 + ions was evaluated by thermodynamic analysis. Finally, the influence of NaOL on hydrogen evolution reaction and manganese electrodeposition was investigated. And the coordination reaction of OL− and Mn2 + was analyzed by FT-IR.

Novel dithiocarbamate (DTC)-modified crosslinked poly(β−cyclodextrin-co-triethylenetetramine) microspheres (DTC-PCDTTM) possessing a particle size distribution of 141 μm with a span value of 0.65 were fabricated and evaluated by Cu2+−MO/TB binary-component systems. DTC-PCDTTM shows excellent simultaneous adsorption performance for Cu2+ and methyl orange (MO) or thymol blue (TB) at a DTC graft ratio of 0.21; it also exhibits eminent regeneration and recyclability. The adsorption isotherm data of DTC-PCDTTM for Cu2+ and MO or TB in Cu2+−MO/TB binary-component systems can be described by the Freundlich and Langmuir models, respectively. The adsorption kinetic data of Cu2+, MO, and TB by DTC-PCDTTM are related to the pseudo-second-order kinetic model. The adsorption is a process of spontaneous endothermic entropy increment. The coordination, electrostatic attraction, and the host−guest interaction of β−cD moieties with contaminants are the primary mechanisms for Cu2+, MO, and TB adsorption. In the Cu2+−MO/TB binary-component systems, competitive adsorption is effectively avoided, and Cu2+ shows good synergistic effects with MO and TB.

A novel magnetic core-shell Fe3O4@[epichlorohydrin-co-triethylenetetramine]n-graft-CSSNa microspheres (Fe3O4@[ECH-co-TETA]n-g-CSSNa) was successfully fabricated through adhesion and subsequent crosslinking of poly(epichlorohydrin-co-triethylenetetramine) copolymer ([ECH-co-TETA]n) on Fe3O4 microspheres and then grafting with dithiocarbamate (−CSS−). The as-prepared Fe3O4@[ECH-co-TETA]n-g-CSSNa microspheres presented an uniform core-layer architecture with approximately 600 nm of particle sizes and 50 nm of coating layer. The −CSS− content of Fe3O4@[ECH-co-TETA]n-g-CSSNa was 1.9257 mmol g−1, and its measured magnetization saturation value was 50.51 emu g−1. Benefiting from its unique microstructure, the resulting adsorbent exhibited high adsorption efficiencies of 293.85, 256.69, 277.93, and 225.07 mg g−1 for Pb2+, Cd2+, Cu2+, and Zn2+ in the pH range of 5.00–8.00 at 293 K, respectively, and rapid adsorption speed of reaching equilibrium within 10 min. Meanwhile, the resulting adsorbent could be easily regenerated at least five cycles with a little capacity loss and exhibited excellent magnetic separation performance. The adsorption data fitted the Langmuir and pseudo-second-order models well, and the adsorption activation energies for Pb2+, Cd2+, Cu2+, and Zn2+ were 26.6359, 15.6302, 26.5152, and 21.1095 kJ mol−1, respectively. All adsorption were spontaneous endothermic processes featuring an entropy increase, involving electrostatic attraction, physisorption, and chemisorption (especially ion exchange and surface complexing adsorption). In chemisorption, S, N, and O in the active layer of Fe3O4@[ECH-co-TETA]n-g-CSSNa were all involved in the formation of a coordination bond and particularly formed a symmetrical S-coordinated four-membered ring of (–CSS−)2M2+. Our work suggests a promising strategy for the rapid and highly efficient removal of heavy metal ions from wastewater.

Problems associated with water eutrophication due to high phosphorus concentrations and related environmentally safe solutions have attracted wide attention. A novel bis(diallyl alkyl tertiary ammonium salt) polymer, particularly poly(N1,N1,N6,N6-tetraallylhexane-1,6-diammonium dichloride) (PTAHDADC), was synthesized and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, mercury intrusion method, and thermogravimetric analysis. The adsorption characteristics in phosphorus were evaluated in dilute solution, and the recycling properties of PTAHDADC were investigated. Results showed that PTAHDADC possessed macropores with a size distribution ranging from 30 to 130 μm concentrating at 63 μm in diameter and had 46.52% of porosity, excellent thermal stability below 530K, and insolubility. PTAHDADC could effectively remove phosphorus at pH = 7–11 and had a removal efficiency exceeding 98.4% at pH = 10–11. The adsorption equilibrium data of PTAHDADC for phosphorus accorded well with the Langmuir and pseudo-second-order kinetic models. Maximum adsorption capacity was 52.82 mg/g at 293 K. PTAHDADC adsorbed phosphorus rapidly and reached equilibrium within 90 min. Calculated activation energy Ea was 15.18 kJ/mol. PTAHDADC presented an excellent recyclability with only 8.23% loss of removal efficiency after five adsorption–desorption cycles. The morphology and structure of PTAHDADC slightly changed as evidenced by the pre- and post-adsorption of phosphorus, but the process was accompanied by the partial deprotonation of the (–CH2)3NH+ group of PTAHDADC. The adsorption was a spontaneous exothermic process driven by entropy through physisorption, electrostatic attraction, and ion exchange. Survey results showed that PTAHDADC was a highly efficient and fast-adsorbing phosphorus-removal material prospective in treating wastewater.

The adsorption characteristic and mechanism of poly(N

A two-component material (Fe

Monodisperse sodium yttrium fluoride corn sticks with hexagonal nanostructure were successfully prepared by a facile and repeatable precipitation transformation method. The phase and morphology of the products were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The growth mechanism was studied, indicating that the initial generated Y(OH)3 gradually translated into YF3 and then transformed into corn stick-like H-NaYF4 nanoparticles owing to the crucial role of fluorine ions in the solution. The up-conversion (UC) luminescence properties of H-NaYF4:20%Yb3+,2%Er3+ nanocrystals were discussed. The intensive green emission in the range of 510–570 nm was attributed to the (2H11/2, 4S3/2)→4I15/2 transition and the weaker red emission between 640 and 680 nm was originating from the 4F9/2→4I15/2 transition.

The influences of oxalate anions on manganese electrodeposition in sulfate solution were investigated on the basis of cathode current efficiency, characterization of SEM-EDX and XRD, solution chemistry calculation, thermodynamics and electrochemical test. The experimental results show that the range of (NH4)2C2O4 was adjusted from 0 mol/L to 4.8 × 10−3 mol/L. And 1.5 × 10−3 mol/L (NH4) 2C2O4 was suitably used with initial pH 7.0. The characterization of SEM indicates that oxalate anions can improve the morphology of electrodeposited films. The electrodeposited films containing manganese were characterized and determined by EDX and XRD. The solution chemistry calculation of catholyte and oxalate anions shows that the main active species are MnSO4, Mn(SO4)2− 2, Mn2+, Mn(SO4)C2O2− 4, MnC2O 4, Mn(NH3)2+, and C2O2− 4. The reaction trend between C2O2− 4 and Mn2+ ions is confirmed by computation of reaction energy. Electrochemical test analysis indicates oxalate anions increase the overpotentials of hydrogen evolution reaction and manganese electrodeposition.

We investigated the reduction leaching process of manganese dioxide ore using black locust as reductant in sulfuric acid solution. The effect of parameters on the leaching efficiency of manganese was the primary focus. Exper- imental results indicate that manganese leaching efficiency of 97.57% was achieved under the optimal conditions: weight ratio of black locust to manganese dioxide ore (WT) of 4:10, ore particle size of 63 μm, 1.7 mol·L -1 H2SO4, liquid to solid ratio (L/S) of 5:1, leaching time of 8 h, leaching temperature of 368 K and agitation rate of 400 r·min -1 . The leaching rate of manganese, based on the shrinking core model, was found to be controlled by inner diffusion through the ash/inert layer com- posed of associated minerals. The activation energy of reductive leaching is 17.81 kJ·mol -1 . To conclude the reaction mechanism, XRD analysis of leached ore residue indicates manganese compounds disappear; FTIR characterization of leached residue of black locust sawdust shows hemicellulose and cellulose disappear after the leaching process.

Surface plasmon resonance sensors based on Au-metalized nanowires in the liquid-core photonic crystal fibers are theoretically analyzed by using finite element method. It is found that the negative refractive index sensitivity exists in the proposed design. The average negative refractive index sensitivity of −4125 nm/RIU (Refractive Index Unit) is achieved in the sensing range of 1.45–1.49, and the sensor resolution is −4.5 × 10 −4 RIU. The sensor with high linearity and accuracy is demonstrated. The new structure is compact in size and easy to fabricate, making it promising for miniaturized complex communication devices. The effects of tuning and optimizing the structural parameters on the plasmonic excitations are also studied. This study provides a basis for investigating the PCF refractive index sensor based on the SPR of the metal nanowires.

Electrolytic manganese residue (EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrate (EMR-CSH). The MnO2 is successfully synthesized from the metal cations extracted from EMR, which can effectively recycle the manganese in the EMR. By the combination of XRD, SEM and EDX analysis, the as-prepared MnO2 is found to exhibit a single-phase with the purity of 90.3%. Furthermore, EMR-CSH is synthesized from EMR via hydrothermal method. Based on the detailed analyses using XRD, FT-IR, FE-SEM, EDX and BET surface area measurement, the product synthesized under the optimum conditions (pH 12.0 and 100 °C) is identified to be a calcium silicate hydrate with a specific surface area of 205 m2/g incorporating the slag-derived metals (Al and Mg) in its structure. The as-synthesized material shows good adsorption properties for removal of Mn2+ and phosphate ions diluted in water, making it a promising candidate for efficient bulk wastewater treatment. This conversion process, which enables us to fabricate two different kinds of valuable materials from EMR at low cost and through convenient preparation steps, is surely beneficial from the viewpoint of the chemical and economical use of EMR.

The extraction of manganese from low-grade manganese oxide ores using CaS derived from CaSO 4 as reductant was investigated. The effects of mass ratio of CaS to ore, reduction temperature, reduction time, liquid to solid ratio (L/S ratio), stirring speed, leaching temperature, leaching time and H 2 SO 4 concentration on the leaching rates of Mn and Fe during the reduction–acid leaching process were discussed. The leaching rates of 96.47% for Mn and 19.24% for Fe were obtained under the optimized conditions of mass ratio of CaS to manganese oxide ore 1:6.7, L/S ratio 5:1, stirring speed 300 r/min, reduction temperature of 95 °C for 2.0 h in the reduction process and leaching stirring speed of 200 r/min, H 2 SO 4 concentration of 1.5 mol/L, leaching temperature of 80 °C for 5 min in the leaching process. In addition, this process can be employed in the recovery of manganese from various manganese oxide ores, and Mn leaching rate above 95% is obtained.

In this study, using coal as a reducer, the thermal decomposition of CaSO3 to produce CaS was carried out at different conditions. The mineralogical composition and microstructure of the as-obtained CaS were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results revealed that single-phase CaS was detected in the product under optimum conditions and the optimal synthesis conditions of CaS were as follows: molar ratio of C and CaSO3 (C/S ratio)=2.5, reaction temperature 1173 K, reaction time 1.5 h and coal particle size 100 mesh. Under the optimum conditions, the purity and yield of CaS are up to 99.15% and 96.52% respectively, which indicated that the decomposition was almost complete and the as-synthesized CaS can be recycled to be a raw material in chemical industry. Meanwhile, thermodynamic calculation showed that the reaction for CaS generation was very complex and CaS was generated mainly through solid–solid reaction and gas–solid reaction.

The zeolite material was first synthesized from electrolytic manganese residue (EMRZ), by a two-step synthetic procedure using NaOH and NaAlO2 within a short aging period. Based on the detailed analyses using XRD, FT-IR, FE-SEM, XRF, CEC and BET surface area measurement, the product synthesized at Si/Al ratio = 1.5 was mainly composed of Na-A zeolite with a specific surface area of 35.38 m2 g−1. Then, the removal characteristics of Mn2+ and Ni2+ ions by EMRZ were investigated under various operating variables like contact time, solution pH and initial metal concentration. The adsorption equilibrium for both Mn2+ and Ni2+ was best described by the Langmuir model, confirming the applicability of monolayer coverage of metal ions onto EMRZ particles. The maximum sorption capacities for Mn2+ and Ni2+ shown by EMRZ were 66.93 mg g−1 and 128.70 mg g−1, respectively. It was also found that adsorption of Mn2+ and Ni2+ by EMRZ followed second-order kinetics and rate constants for Mn2+ and Ni2+ sorption were found to be 0.001091 and 0.005668 g mg−1 min−1, respectively at 30 °C. These results indicate that the synthesized EMRZ is a promising and low-cost adsorbent for removing heavy metals from wastewater due to higher adsorption capacity than other adsorbents.

The zeolite synthesized from electrolytic manganese residue (EMRZ) was investigated as adsorbents to remove methylene blue (MB), a cationic dye, from aqueous solutions. The effects of various experimental parameters, such as contact time, initial MB concentration, temperature and pH on the adsorption capacity were investigated. The results showed that the adsorption behavior of EMRZ was greatly affected by pH and temperature. And higher solution pH and temperature resulted in higher adsorption capacity of MB. The experimental data were also analyzed by the Langmuir and Freundlich models of adsorption. The adsorption of MB onto EMRZ agrees well with the Langmuir isotherm and the thermodynamic parameters such ΔH, ΔS and ΔG were determined to be +37.46 kJ mol−1, +201.03 J mol−1 K−1, −23.45 to −25.46 kJ mol−1, respectively, showing adsorption to be an endothermic yet spontaneous process. Moreover, pseudo-first-order and pseudo-second-order models were considered to evaluate the rate parameters. The adsorption process could be described well by pseudo-second-order model, with an activation energy of +13.71 kJ mol−1. These results indicate that the synthesized EMRZ is a promising and low-cost adsorbent for removing dyes from wastewater due to the high adsorption capacity.

A three-component magnetic material, namely, Fe3O4@SiO2@CaSiO3, which featuring an Fe3O4@SiO2 core and a layered porous CaSiO3 shell, was synthesized via precipitation and utilized as an adsorbent to remove Ag+ from wastewater. The structure, morphology, composition, and magnetic properties of this material were analyzed by a series of characterization techniques, and its adsorption efficiency, adsorption thermodynamics, kinetic characteristics, and recyclability were investigated in detail. The magnetic Fe3O4@SiO2@CaSiO3 composite possessed a core–shell structure, with a cotton-like morphology, a specific surface area of 75.97 m2·g−1, pore size of 11.4 nm, pore volume of 0.36 cm3·g−1, and magnetization saturation of 60.5 emu·g−1. The adsorption equilibrium data of Ag+ adsorption by Fe3O4@SiO2@CaSiO3 fitted the Redlich–Peterson model well, and the equilibrium adsorption capacity of the material for Ag+ reached 127.84 mg·g−1 at an initial concentration of 225 mg·L−1 and temperature of 293 K. Kinteic studies showed that the adsorption process conformed well to the pseudo-second-order model and reached equilibrium within 150 min. The adsorption process was endothermic, with an activation energy of 8.475 kJ·mol−1 and accompanied by Ag O bonding and Ca2+ release. Therefore, the adsorption mechanism involved in Ag+ removal includes not only physisorption and ion exchange but also chemisorption, which is controlled by surface OH and O groups. The percentage of Ag+ removal tended to stabilize after five cycles of Fe3O4@SiO2@CaSiO3 reuse and but decreased by only 14.34%. Synthesized Fe3O4@SiO2@CaSiO3 exhibited excellent adsorption, regeneration, and magnetic separation performance. Thus, the synthesized Fe3O4@SiO2@CaSiO3 may potentially be applied to remove Ag+.

This paper presents a theoretical investigation on an analyte-filled core self-calibration microstructured optical fiber plasmonic refractive index sensor. The proposed microstructured optical fiber sensor introduces the concept of simultaneous detection in different ranges of wavelength because the sensing performance of the sensor in different wavelength ranges is relatively high, which will be useful for high accuracy measurement. The resonant peak 1 and peak 2 are stronger and more sensitive to the variation of analyte refractive index than any other peaks in this kind of microstructured optical fiber. An average refractive index sensitivity of −4354.3 nm/RIU (refractive index unit) and 2280 nm/RIU in the dynamic index range from 1.46 to 1.485 as well as −2660 nm/RIU and −4240 nm/RIU from 1.50 to 1.52 corresponding to the peak 1 and peak 2 can be obtained, respectively. The self-calibration sensor demonstrates high linearity and accuracy. The influence of the structural parameters on the plasmonic excitations is also studied, with a view of turning and optimizing the resonant spectrum.

We analyzed the leaching behavior and chemical speciation of heavy metals in a landfill of electrolytic manganese residue (EMR). The results showed that most of Pb, Cr, As, Cu, and Zn were associated with F4 (residual fraction) and Mn and Co were mainly present in F1 (exchangeable and weak acid soluble fraction). In order to evaluate potential risks of heavy metals to the landfill, modified potential ecological risk index (MPER), potential ecological risk index (PER), index of geo-accumulation (Igeo) assessment, and risk assessment code (RAC) were employed. Ranking order for potential risk based on RAC assessment is Mn > Co > Zn > Cu > Cr = As = Pb. Results from Igeo assessment indicates that Mn poses a potential for high risk to human health and the ecosystem. MPER, which integrates the characteristics of PER and RAC, shows that the potential risks of heavy metals are in the order of As > Cu > Mn > Co > Pb > Cr > Zn. The analysis indicates that Mn, Co, As, and Cu within EMR pose a potential risk ...

This article presents the fabrication of hexagonal yttrium hydroxide fluoride nanobundles via one-pot hydrothermal process, using yttrium nitrate, sodium hydroxide and ammonia fluoride as raw materials to react in propanetriol solvent. The X-ray diffraction pattern clearly reveals that the grown product is pure yttrium hydroxide fluoride, namely Y(OH)(2.02)F-0.98. The morphology and microstructure of the synthesized product is testified to be nanobundles composed of numerous oriented-attached nanoparticles as observed from the field emission scanning electron microscopy (FESEM). The chemical composition was analyzed by the energy dispersive spectrum (EDS), confirming the phase transformation of the products which was clearly consistent with the result of XRD analysis. It is proposed that the growth of yttrium hydroxide fluoride nanobundles be attributed to ion exchange and precipitation transformation. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.

The polarization filter characters of a gold-coated and liquid-filled photonic crystal fiber are studied using the finite element method. Results show that the resonance strength and wavelengths are different in two polarized directions. Filling liquid of refractive index n=1.33 (purified water) in holes in longitudinal direction can increase the loss of core mode polarized in the y-direction around the resonance peak. The resonance strength is much stronger in y-polarized direction than in x-polarized direction. The resonance strength can achieve 508dB/cm in y-polarized direction at the communication wavelength of 1311nm in one of our structures. Moreover, the full width half maximum is only 20nm. Such a small number makes such photonic crystal fibers promising candidate to filter devices. A liquid filled PCF of the small hole in the fiber core is designed and we find that filling liquid increases the resonance strength peak by thirty eight percent for the y-polarized resonance point.

To investigate the distribution of positive allergens in patients with allergic rhinitis in Changzhou.A total of 4242 cases with allergic symptoms and signs underwent skin prick test with 16 kinds of standardized allergens. The common allergens were found out. The samples were stratified on seven age groups to analysis the distributive characteristics of allergens responsible for each group. The samples were also stratified on children group and adults group to analysis their response degree to dust mite.2638 cases (62.19%) had the positive reaction, including male 1380 (52.3%) cases, female 1258 (47.7%) cases. Dermatophagoides farinae and dermatophagoides pteronyssinus had the highest positive ratio (85.86%, 83.55%) in inhalation group, followed cockroach (11.49%) and Humulus L. (9.82%), fungus (2.92%) in the lower positive ratio. Shrimp (5.76%) was the most common allergen in food group. The distribution of common allergens in different age groups was variable. There was significantly higher sensitivity to dust mite between children group compared to adults group (P0.01).The study shows that Dust mite was the mostly responsible common allergen in Changzhou district. The distribution of common allergens in children group and adults group was variable.