Heteroatoms doped iron oxide-based catalyst prepared from zinc slag for efficient selective catalytic reduction of NO_(x) with NH_(3)

Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment,and the development of deNO_(x) catalysts with low-cost and high performance is an urgent requirement.Iron oxide-based material has been explored for promising deNO_(x) catalysts.However,the unsatisfactory low-temperature activity limits their practical applications.In this study,a series of excellent low-temperature denitrification catalysts(Ha-FeO_(x)/yZS)were prepared by acid treatment of zinc slag,and the mass ratios of Fe to impure ions was regulated by adjusting the acid concentrations.Ha-FeO_(x)/yZS showed high denitrification performance(>90%)in the range of 180–300℃,and the optimal NO conversion and N2 selectivity were higher than 95%at 250℃.Among them,the Ha-FeO_(x)/2ZS synthesized with 2 mol/L HNO3 exhibited the widest temperature window(175–350℃).The excellent denitrification performance of Ha-FeO_(x)/yZS was mainly attributed to the strong interaction between Fe and impurity ions to inhibit the growth of crystals,making Ha-FeO_(x)/yZS with amorphous structure,nice fine particles,large specific surface area,more surface acid sites and high chemisorbed oxygen.The in-situ DRIFT experiments confirmed that the SCR reaction on the Ha-FeO_(x)/yZS followed both Langmuir-Hinshelwood(L-H)mechanism and Eley-Rideal(E-R)mechanism.The present work proposed a high value-added method for the preparation of cost-effective catalysts from zinc slag,which showed a promising application prospect in NO_(x) removal by selective catalytic reduction with ammonia.

Effects of earthquake on damage evolution and failure mechanism of key rock pillars in underground engineering

Rock pillar is the key supporting component in underground engineering.During an earthquake,the key rock pillar must bear both the seismic load and the load transferred from other damaged pillars.This paper attempts to reveal the influence of the mainshock on damage evolution and failure characteristic of the key rock pillar during aftershocks by cyclic loading test of marble.Four levels of pre-damage stress(i.e.,10,30,50 and 70 MPa)in the first cycle were used to simulate the mainshock damage,and then cyclic stress with the same amplitude(namely 10 MPa)was conducted in the subsequent cycles to simulate the aftershock until rock failure.The results indicate that the presence of pre-damage has an obvious weakening effect on the bearing capacity and deformation resistance of rock materials during the aftershock process.Besides,the increase of pre-damage significantly changes the final failure pattern of the key rock pillar,and leads to an increase in the proportion of small-scale rock fragments.This study may contribute to understanding the seismic capacity of the unreinforced rock pillar during mainshock-aftershock seismic sequences and to optimizing the design of the key rock pillar in underground engineering.

Enhanced inhibition of talc flotation using acidified sodium silicate and sodium carboxymethyl cellulose as the combined inhibitor

The flotation separation of chalcopyrite and talc is challenging due to their similar natural floatability characteristics.Besides,it is usually difficult to effectively inhibit talc by adding sodium carboxymethyl cellulose(CMC)alone during chalcopyrite flotation.Here,a combined inhibitor comprising acidified sodium silicate(ASS)and CMC was employed to realize effective flotation separation of chalcopyrite and talc,and the combined inhibition mechanism was further investigated.Microflotation results showed that adding ASS strengthened the inhibitory effect of CMC on talc and improved the separation of chalcopyrite and talc.The zeta potential,Fourier transform infrared,and X-ray photoelectron spectroscopy analysis indicated that CMC was mainly adsorbed on the talc surface via hydroxyl and carboxyl groups.Moreover,the addition of ASS improved the adsorption of carboxyl groups.Furthermore,the adsorption experiments and apparent viscosity measurements revealed that adding ASS dispersed the pulp well,which reduced the apparent viscosity,improved the adsorption amount of CMC on the talc surface,and enhanced the inhibition of talc in chalcopyrite flotation.

Effective recovery of chalcopyrite at low temperatures using modified ester collector

The effect of a modified ester collector named as BL on the flotation of chalcopyrite at low temperatures was investigated by micro-flotation tests,contact angle measurements,adsorption experiments,laser particle size analysis,cryogenic transmission electron microscopy(Cryo-TEM)and Fourier transform infrared(FTIR)analyses.Micro-flotation tests proved that the collecting ability of BL for chalcopyrite was significantly better than that of N,N-diethyl dithiocarbamate propiononitrile ester(ester-105)at low temperatures.Combined with laser particle size,Cryo-TEM and FTIR analyses,it was found that the particle size of BL in water was smaller than that of ester-105,and the distributed density of BL was higher than that of ester-105 at low temperatures,indicating that BL dispersed well at low temperatures.Therefore,BL was more easily adsorbed on the chalcopyrite surface and improved the surface hydrophobic degree of chalcopyrite,which were also confirmed by the contact angle measurements and adsorption experiments.

Adsorption mechanism of sodium oleate and styryl phosphonic acid on rutile and amphibole surfaces

A reagent combination of sodium oleate(NaOl)and salicyl hydroximic acid was employed as the roughing and scavenging collectors,whereas styryl phosphoric acid(SPA)and octanol were employed as the cleaning collectors.Results of bench-scale flotation demonstrate that the dosage of SPA can be reduced by about 80%,and that a better flotation index can be obtained using the proposed reagent system.The results of adsorption amount and contact angle measurements indicate that the rutile surface adsorbed not only a large amount of residual NaOl but also SPA and a small amount of NaOl remained on the amphibole surface in strong acidic solution.The hydrophobic difference between rutile and amphibole surfaces was therefore amplified in cleaning,and their further separation became much easier consequently.

Galvanic effect of magnetite on electrochemical oxidation of arsenopyrite in acidic culture medium

The galvanic interaction of arsenopyrite−magnetite in acidic culture medium was investigated by electrochemical measurements,X-ray photoelectron spectroscopy characterization and leaching experiments.The results indicated that the rest potential of magnetite was 321 mV,which was more anodic than 223 mV of arsenopyrite,and the galvanic current was 7.40μA,verifying the existence of the galvanic interaction between arsenopyrite and magnetite.The galvanic potential and polarization curves suggested that the redox behaviors of arsenopyrite dominated the overall galvanic interaction.The galvanic interaction enhanced the electrochemical dissolution of arsenopyrite with the generation of more oxidation products(S^(0),SO_(3)^(2−),SO_(4)^(2−)and AsO_(3)^(3−)) on arsenopyrite and an increase in the chemical reactivity of the surface.Leaching experiments of 6 days showed that the presence of magnetite improved the arsenic release from arsenopyrite by 30 mg/L,and further confirmed the enhanced oxidation of arsenopyrite when coupled with magnetite.

Synthesis of cobalt-doped ZnO/rGO nanoparticles with visible-light photocatalytic activity through a cobalt-induced electrochemical method

ZnO is a semiconductor photocatalyst widely applied in photodegradation of organic pollutants and in photoelectric conversion. ZnO exhibits low photocatalytic activity due to poor absorption in the visible region. In this work, a novel cobalt-induced electrochemical growth method was developed to synthesize cobalt-doped ZnO/rGO nanoparticles in an aqueous solution at room temperature. Cobalt-doped ZnO/rGO nanoparticles exhibited wider visible-light absorption band ranging from 400 nm to 700 nm due to cobalt doping. The surface structure of ZnO formed by the cobalt-induced electrochemical method without other ions is suitable for photocatalytic reactions. The cobalt-doped ZnO/rGO nanoparticles were found to exhibit in photodegradation and photo-electrochemical measurements and exhibited enhanced photocatalytic activity under visible-light irradiation.

Dissolution of gold in chalcopyrite-containing cyanide solutions

The gold dissolution in anoxic cyanide solution in the presence of chalcopyrite was studied with a rotating disc electrode.It was found that the presence of chalcopyrite reduced and enhanced the dissolution activity of pure gold in the low and high potential regions,respectively.The dissolution of gold was diffusion-controlled at low potentials(≤177 mV)and low cyanide concentrations(≤980 mg/L);however,above the cyanide concentration of 980 mg/L,the current density of gold decreased and the dissolution of gold changed from diffusion-control to electrochemical reaction-control.At high potentials(>177 mV),gold dissolution was always controlled by diffusion.In cyanide solution containing chalcopyrite,appropriate increase of pH value and temperature could accelerate the dissolution of gold,but high pH value would promote the generation of passivation,which was harmful for the dissolution of gold in cyanide solution.

Homogeneous distributed natural pyrite-derived composite induced by modified graphite as high-performance lithium-ion batteries anode

Natural minerals-based energy materials have attracted enormous attention because of the advantages of good materials consistency,high production,environmental friendliness,and low cost.The uniform distribution of grains can effectively inhibit the aggregation of active materials,improving lithium storage performance.In this work,natural graphite is modified by polyvinylpyrrolidone to obtain modified graphite with reduced size and better dispersion.Natural pyrite composite polyvinylpyrrolidone-modified graphite(pyrite/PG)material with uniform particle distribution is obtained by the ball milling process.The subsequent calcination process converts pyrite/PG into Fe_(1-x)Scompounded with polyvinylpyrrolidone-modified graphite(Fe_(1-x)S/PG).The homogeneous grain distributions of active material can facilitate the faster transfer of electrons and promote the efficient utilization of active materials.The as-prepared Fe_(1-x)S/PG electrode exhibits a remarkably reversible specific capacity of 613.0 mAh·g^(-1)at 0.2 A·g^(-1)after 80 cycles and an excellent rate capability of 523.0 mAh·g^(-1)at 5 A·g^(-1).Even at a higher current density of 10 A·g^(-1),it can deliver a specific capacity of 348.0 mAh·g^(-1).Moreover,the dominant pseudocapacitance in redox reactions accounts for the impressive rate and cycling stability.This work provides a low-cost and facile method to fabricate natural mineral-based anode materials and apprise readers about the impact of uniform particle distribution on lithium storage performance.

Ozone generation enhanced by silica catalyst in packed-bed DBD reactor

In this paper,three dielectric barrier discharge(DBD)configurations,which were plain DBD with no packing,DBD with packed pure quartz fibers and DBD with packed loaded quartz fibers,were employed to investigate the effect and catalytic mechanism of catalyst materials in a packed-bed ozone generator.From the experimental results,it was clear that the DBD configuration with packed pure fibers and packed loaded fibers promotes ozone generation.For the packed-bed reactor,ozone concentration and ozone yield were enhanced by an increase of electric field in the discharge gap with the packed-bed effect.Meanwhile,the enhancement of ozone concentration and yield for the DBD reactor packed by loaded fibers with silica nanoparticles was due to the catalysis of silica nanoparticles on the fiber surface.The adsorption of silica nanoparticles on the fiber surface can prolong the retention time of active species and enhance surface reactions.

Comparative Experimental Analysis on Coal Spontaneous Combustion

The goal of this study was to investigate coal quality features and their relationship to coal spontaneous combustion characteristics in multi-seam coal mines to better predict when coal spontaneous combustion is likely to occur.To that end,coal samples of various particle sizes were obtained from five coal seams(Nos.6,8,9,12 and 20)in the Shuangyashan City Xin’an Coal Mine.The samples were then respectively heated using a temperature programming system to observe and compare similarities and differences in the sponta-neous combustion process of different particle sizes in response to rising temperature.The experimental results show,that in all five coal seams,the concentration of CO,C_(2)H_(4),and C_(2)H_(6) increased with a certain degree of regularity as a function of rising temperature.However,of these three gasses,only CO and C_(2)H_(4) can be used as indicators to predict coal mine spontaneous combustion.The critical temperature for samples from all five coal seams ranged from 50–85℃,while the dry cracking temperature of coal seams 8 and 12(80–100℃)were lower than those of 6,9,and 20(100–120℃).Furthermore,the production rate of CO,C_(2)H_(4),and C_(2)H_(6) is related to both coal particle size and temperature.The smaller the particle size,the faster the production rate;and the higher the temperature,the more gas that gets produced.All five coal seems are mainly com-posed of long flame coal.However,they differ in that the No.12 coal seam contains weak cohesive coal;the No.8 coal seam contains lean and gas coal;and the Nos.6,9,and 20 coal seams contain a certain amount of anthracite.During the programmed coal heating,the CO,C_(2)H_(4),and C_(2)H_(6) release trend for the coal seams was No.12>No.8>Nos.6,9,and 20.These results demonstrate that the presence of weak cohesive coal and anthracite highly influence the concentration of CO,C_(2)H_(4),and C_(2)H_(6) released during coal spontaneous combustion.

Performance of different macrophytes in the decontamination of and electricity generation from swine wastewater via an integrated constructed wetland-microbial fuel cell process

Plants constitute a major element of constructed wetlands(CWs).In this study,a coupled system comprising an integrated vertical flow CW(IVCW) and a microbial fuel cell(MFC) for swine wastewater tre atment was developed to research the effects of macrophytes commonly employed in CWs,Canna indica,Acorus calamus,and Ipomoea aquatica,on decontamination and electricity production in the system.Because of the different root types and amounts of oxygen released by the roots,the rates of chemical oxygen demand(COD) and ammonium nitrogen(NH4^+-N) removal from the swine wastewater differed as well.In the unplanted,Canna indica,Acorus calamus,and Ipomoea aquatica systems,the COD removal rates were 80.20%,88.07%,84.70%,and 82.20%,respectively,and the NH4+-N removal rates were 49.96%,75.02%,70.25%,and 68.47%,respectively.The decontamination capability of the Canna indica system was better than those of the other systems.The average output voltages were 520±42,715±20,660±27,and 752±26 mV for the unplanted,Canna indica,Acorus calamus,and Ipomoea aquatica systems,respectively,and the maximum power densities were 0.2230,0.4136,0.3614,and0.4964 W/m^3,respectively.Ipomoea aquatica had the largest effect on bioelectricity generation promotion.In addition,electrochemically active bacteria,Geobacter and Desulfuromonas,were detected in the anodic biofilm by high-throughput sequencing analysis,and Comamonas(Proteobacteria),which is widely found in MFCs,was also detected in the anodic biofilm.These results confirmed the important role of plants in IVCW-MFCs.

Spatio-temporal distribution of gaseous pollutants from multiple sources in industrial buildings with different flow patterns

Energy consumption of industrial buildings has remained continuously high,and the environmental quality requirements are also constantly improving.Only by improving industrial environmental control technology based on the transport mechanism of the pollution,can the energy consumption of industrial building environmental control be further reduced,and the environmental quality of industrial buildings can be improved as well.Therefore,after verifying the numerical simulation by experiments,this study uses a self-label method to investigate the spatio-temporal distribution of gaseous pollutants from multiple time-series sources in industrial plants with different length-span ratios.The results show that,the polluted flow in plants with different aspect ratios have different flow patterns:(i)the,,Back-mixingw flow pattern occurs when the ratio of ventilation rate 6 and polluted flow rate at the exhaust height b is less than 1,i.e.,G/L_(p)<1,and(ii)the"One-way"flow pattern occurs when G/L_(p)>1.For plants with the"Back-mixing"pattern,the following source pollutants enter a density stratified environment induced by the retained pre-source pollutants.The flow of following source pollutants released at the same intensity as the precursor source can reach the roof,while those with low velocity and density difference may be blocked during the ascending process.The maximum height zm of the flow of the following source is related to both the initial Froude number Fr_(o)of the following source and the unsteady vertical density gradient of the fluid in the indoor environment dpa/dz.For plants with the,,One-way,/pattern,the flow from the following source enters into an environment with approximately uniform density.Under the condition of positive buoyancy,design parameters of ventilation corresponding to the vicinity of G/L_(p)=1 may be the optimal solution for safety and energy conservation.

Taxonomic notes on some species of Neolucanus Thomson(Coleoptera: Lucanidae) from China

As a part of ongoing investigations on Neolucanus from Chinese fauna, N. swinhoei hengshanensis Ichikawa ＆ Fujita, 1987 is confirmed as a junior synonym of N. imitator Kriesche, 1935 based on the types examination. Holotype of the little-known species of N. tao Kriesche, 1935 and the male genitalia are illustrated for the first time, in comparison with the sympatric species of N. guangxi Schenk, 2009. Wrong diagnoses of N. nitidus （Saunders, 1854） are pointed out in two widely used books published by Japanese researchers. In order to correct these errors, type specimen of this species and its intraspecific variations are exhibited, with brief discussion on its problematic subspecies. The poorly known species ofN. pallescens Leuthner, 1885 is redescribed with the discovery of its false type specimen. All of the type habitus, figures of male genitalia including female genitalia are given.

Preparation of nZVI embedded modified mesoporous carbon for catalytic persulfate to degradation of reactive black 5

High-efficiency and cost-effective catalysts with available strategies for persulfate(PS)activation are critical for the complete mineralization of organic contaminants in the environmental remediation and protection fields.A nanoscale zero-valent iron-embedded modified mesoporous carbon(MCNZVI)with a core-shell structure is synthesized using the hydrothermal synthesis method and high-temperature pyrolysis.The results showed that nZVI could be impregnated within mesoporous carbon frameworks with a comparatively high graphitization degree,rich nitrogen doping content,and a large surface area and pore volume.This material was used as a persulfate activator for the oxidation removal of Reactive Black 5(RB5).The effects of the material dosage,PS concentration,pH,and some inorganic anions(i.e.,Cl^(−),SO_(4)^(2−))on RB5 degradation were then investigated.The highest degradation efficiency(97.3%)of RB5 was achieved via PS(20 mmol/L)activation by the MCNZVI(0.5 g/L).The pseudo-first-order kinetics(k=2.11×10^(−2)min^(−1))in the MCNZVI/PS(0.5 g/L,20 mmol/L)was greater than 100 times than that in the MCNZVI and PS.The reactive oxygen species(ROS),including^(1)O_(2),SO_(4)^(·−),HO^(.),and·O_(2)^(−),were generated by PS activation with the MCNZVI.Singlet oxygen was demonstrated to be the primary ROS responsible for the RB5 degradation.The MCNZVI could be reused and regenerated for recycling.This work provides new insights into PS activation to remove organic contamination.

Taxonomic revision of Prosopocoilus gracilis(Saunders,1854) and its allied species from China(Coleoptera:Lucanidae)

Prosopocoilus gracilis （Saunders, 1854） and its seven allied species from China are revised. Lectotype, paralectotypes of P. gracilis （Saunders, 1854） and P. denticulatus （Boileau, 1901） are designated. The doubtful species, P. piceipennis （Westwood, 1855） is evidently confirmed as a valid species with verification of its type depository. Two highly similar species, P. crenulidens （Fairmaire, 1895） and P. denticulatus （Boileau, 1901） are compared in detail for correcting longstanding wrong diagnoses of them. P. similis Schenk, 2009 is illustrated with male genitalia firstly. Two recently-published species, P. andreasi Schenk, 2009 and P. katsurai Fujita, 2010 are treated as new junior synonyms. All the five valid species in this paper are redescribed, with illustrations of adult （including type） habitus, male and female genitalia if they are available. A key to large males is provided for identifying them briefly.

Facile construction of honeycomb-shaped porous carbon electrode materials using recyclable sodium chloride template for efficient lithium storage

Carbon materials are the preferred anode materials for Li-ion batteries.Here,we propose an easy and sustainable strategy to prepare honeycomb-shaped porous carbon(HPC)electrode materials through a process involving simple calcination and subsequent water washing by using polyvinyl-pyrrolidone(PVP)as carbon source and NaCl as pore-forming agent.A controllable cavity size and distribution of the carbon materials can be readily obtained solely by adjusting the NaCl amount.Results showed that the optimized HPC sample had a relatively uniform cavity distribution and a highly porous structure.Moreover,the special honeycomb-shaped structure was conducive to the electronic conductivity of the electrode materials,provided a short path for Li-ion transport and a wide interface with the electrolyte,and buffered the volume change of active materials.The special honeycomb-shaped structure was also maintained well after long cycles,which improved electrode stability.When used as anode materials for Li-ion batteries(LIBs),the sample demonstrated excellent cycling stability and rate performance,with a high specific capacity of 230 mA hg^-1 and a reversible capacity of 197 mA hg^-1,after 1200 cycles at 2 C.Overall,we introduced a simple strategy for the potential mass production of porous carbon materials for LIBs.

The complete mitochondrial genome of Odontolabis fallaciosa(Coleoptera: Lucanidae) with its phylogenetic implications

In this study, the complete mitochondrial genome of Odontolabis fallaciosa was sequenced for the first time using the next generation sequencing method. Like most reported mitogenomes of scarab beetles, it was a double-stranded circular molecule, consisting of 13 protein-coding genes（PCGs）, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region. The mitogenome of O. fallaciosa was 19,614 bp in length. The base nucleotide composition in the mitogenome of O. fallaciosa was： A（40.0%）, T（30.5%）, C（18.5%） and G（11.0%）, with the total AT content of 70.5%. The phylogenetic analysis of twelve species of stag beetles and other three scarab beetles showed that O. fallaciosa and Aegus angustus share a common ancestor. The mitogenomic data could provide a reliable reference for the future study on conservation, phylogeny and even evolution of these species.

New synonymies and records of the stag-beetle genus Aegus Mac Leay from Chinese fauna(Coleoptera:Lucanidae)

Four new synonyms in the stag-beetle genus Aegus MacLeay from Chinese fauna are proposed and discussed based on their type specimens： A. pichoni Didier 1931, syn. nov. = A. laevicollis Saunders 1854; A. beauchenei Boileau 1902, syn. nov. and A. caprinus Didier, 1928, syn. nov. =A. taurus Boileau, 1899; A. dispar Dider 1931, syn. nov. =A. kuangtungensis Nagel, 1925. A species checklist with fifteen species of this genus from China is given, including two new record species, A. labilis Westwood, 1864 from Xizang and A. coomani Didier, 1926 from Guangxi.