Separation of halogens and recovery of heavy metals from secondary copper smelting dust

The separation of halogens and recovery of heavy metals from secondary copper smelting(SCS)dust using a sulfating roasting−water leaching process were investigated.The thermodynamic analysis results confirm the feasibility of the phase transformation to metal sulfates and to gaseous HF and HCl.Under the sulfating roasting conditions of the roasting temperature of 250℃ and the sulfuric acid excess coefficient of 1.8,over 74 wt.%of F and 98 wt.%of Cl were volatilized into flue gas.Approximately 98.6 wt.%of Zn and 96.5 wt.%of Cu in the roasting product were dissolved into the leaching solution after the water leaching process,while the leaching efficiencies of Pb and Sn were only 0.12%and 0.22%,respectively.The mechanism studies indicate the pivotal effect of roasting temperature on the sulphation reactions from various metal species to metal sulfates and the salting out reactions from various metal halides to gaseous hydrogen halides.

Preliminary measurements of boundary layer reactive halogens based on MAXDOAS technique over Salt Lake in West China

The reactive halogens play key roles in the destruction of boundary layer ozone by catalytic reactions and provide a fast pathway to the sedimentation of elemental gaseous mercury.The presence of bromine oxides in the lower

Deciphering fluid origins in the Paleozoic Laoshankou Fe-Cu-Au deposit, East Junggar: Constraints from noble gases and halogens

To constrain the ore-fluid source(s)of the Laoshankou Fe-Cu-Au deposit(Junggar orogen,NW China),we analyzed the fluid inclusion(FI)noble gas(Ar,Kr and Xe)and halogen(Cl,Br and I)compositions in the hydrothermal epidote and quartz.Four hypogene alteration/mineralization stages,including(I)pre-ore Ca-silicate,(II)early-ore amphibole-epidote-magnetite,(III)late-ore pyrite-chalcopyrite,and(IV)post-ore hydrothermal veining,have been identified at Laoshankou.Stage II FIs have salinity of 15.7 wt.%(NaCl eq.),I/Cl molar ratios of 75×10^(−6)-135×10^(−6),and Br/Cl molar ratios of 1.4×10^(−3)-2.1×10^(−3).The moderately-high seawatercorrected Br*/I ratios(0.5-1.5)and low 40ArE/Cl slope(-10−5)indicate the presence of sedimentary marine pore fluid,which was modified by seawater reacting with the Beitashan Fm.volcanic rocks.Stage III fluid is more saline than their stage II and IV counterparts,reaching up to 23.3 wt.%(NaCl+CaCl2 eq.)close to halite saturation(-26 wt.%).The fluid has I/Cl ratios of 75×10^(−6)-90×10^(−6) and Br/Cl ratios of 1.5×10^(−3)-1.8×10^(−3).Considering the increasing 40ArE/Cl trend toward bittern brine and the higher 36Ar content than air-saturated water(ASW),a bittern fluid source is inferred from seawater evaporation,which was modified by interaction with organic-rich marine sedimentary rocks.Stage IV FIs have lower temperature(110-228°C)and Br/Cl(0.90×10^(−3)-1.2×10^(−3)),but higher 36Ar content than ASW,indicative of dissolved evaporite or halite input.Considering also the lowδDfluid(−114‰to−144‰)andδ18Ofluid(2.1‰-3.5‰)values,meteoric water(with minor dissolved evaporites)likely dominated the stage IV fluid.The evaporites may have formed through continuous evaporation of the stage III surface-derived bittern.Involvement of non-magmatic fluids and different ore-fluid origins in stages II and III suggest that the ore-forming process was different from a typical magmatichydrothermal fluid-dominated skarn mineralization,which was previously proposed for Laoshankou.Our noble gas and halogen study at Laoshankou provide new insights on the fluid sources for the Paleozoic Fe−Cu(−Au)deposits in the Central Asian Orogenic Belt(CAOB),and our non-magmatic fluid source interpretation is consistent with the basin inversion setting for the mineralization.

Textural and compositional variation of mica from the Dexing porphyry Cu deposit:constraints on the behavior of halogens in porphyry systems

The Dexing porphyry deposit is the largest porphyry Cu–Mo–Au deposit in South China.Biotite composition can record the physicochemical conditions and evolution history of magmatic-hydrothermal system.Biotite from the Dexing porphyry deposit could be divided to three types:primary magmatic biotite(Bi-M),hydrothermal altered magmatic biotite(Bi-A)and hydrothermal biotite(Bi-H).The temperature of Bi-M and Bi-H range from 719 to 767℃ and 690 to 727℃,respectively.Both magmatic and hydrothermal biotite have high Fe^(3+)/Fe^(2+)ratios(from 0.18 to 0.24)and XMgvalues(from 0.57 to 0.66),indicating a high oxygen fugacity.BiM has F lower than Bi-A and Bi-H(up to 0.26 wt%),but has Cl(Cl=0.18–0.30 wt%)similar to Bi-A and Bi-H(Cl=0.21–0.35 wt%),suggesting that high Cl/F ratios of early hydrothermal fluid may result from the exsolution from high Cl magma.From potassic alteration zone to phyllic and propylitic alteration zones,Cl decreases with increasing Cu,whereas F increases roughly.Therefore,Cl mostly originate from magma,but enrichment of F possibly results from reaction of fluids and Neoproterozoic strata.Negative correlation between Cl and Cu indicates that Cl might act as an important catalyst during Cu mineralization process.Biotite from Dexing has similar halogen compositions to other porphyry Cu-/Mo deposits in the world.Chlorine contents of hydrothermal fluid may be critical for Cu transportation and enrichment,while consumption of Cl would promote Cu deposition.

Anomalous bond-length behaviors of solid halogens under pressure

The three halogen solids(Cl_(2),Br_(2),and I_(2))have the isostructural diatomic molecular phaseⅠwith a space group of Cmca at ambient pressure.At high pressure,they all go through an intermediate phaseⅤwith incommensurate structures before eventually dissociating into the monatomic phaseⅡ.However,a new structural transition between phaseⅠandⅤwith anomalous bond-length behavior was observed in bromine under pressure,which,so far,has not been confirmed in iodine and chlorine.Here,we perform first-principles calculations for iodine and chlorine.The new structural transition was predicted to be common to all three halogens under pressure.The transition pressures might be systematically underestimated by the imperfect van der Waals correction method,but they follow the order Cl_(2)>Br_(2)>I_(2),which is consistent with other pressure-induced structural transitions such as metallization and the molecular-to-monatomic transition.

SOMO-HOMO level conversion in triarylmethyl-cored N-heterocyclic carbene-Au(I)complexes triggered by selecting coordination halogens

Conventionally,organic radicals adhere to the Aufbau principle,the energy level of the singly occupied molecular orbital(SOMO)is not below the highest occupied molecular orbital(HOMO),but somewhat abnormal phenomena have appeared recently.In this study,we introduce a novel strategy by incorporating unique NHC-Au-X units into a tris(2,4,6-trichlorophenyl)methyl(TTM)system to create metal-involved open-shell complexes,denoted as TTM-NHC-Au-X(X=I,Br,or Cl).Density-functional theory calculations were used to predict an inversion in the energy of the SOMO and highest doubly occupied molecular orbital(HOMO)of TTM-NHC-Au-I,which is supported by experimental results.Organometallic radicals TTM-NHC-Au-X demonstrated distinct properties with different coordinated halides.The radical behaviors have been investigated by EPR,UV-vis spectroscopy and cyclic voltammetry,additional structural information provided by structurally comparing related the precursor complexes given by X-ray crystallography.TTM-NHC-Au-I with SOMO-HOMO conversion(SHC)features a highly thermal decomposition temperature up to 305℃.Furthermore,the photostability of TTM-NHC-Au-I was found to be 75and 23 times greater than that of TTM-NHC-Au-Br and TTM-NHC-Au-Cl,respectively.These findings provide valuable insights into the structural and electronic design principles governing the occurrence of SOMO-HOMO conversion in open-shell systems.

Electrode/Electrolyte Optimization‑Induced Double‑Layered Architecture for High‑Performance Aqueous Zinc‑(Dual)Halogen Batteries

Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation.Herein,a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid(ZEA)artificial film and ZnF2-rich solid electrolyte interphase(SEI)layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.The ZEA-based artificial film shows strong affinity for the ZnF2-rich SEI layer,therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode.Such double-layered architecture not only modulates Zn2+flux and suppresses the zinc dendrite growth,but also blocks the direct contact between the metal anode and electrolyte,thus mitigating the corrosion from the active species.When employing optimized metal anodes and electrolytes,the as-developed zinc-(dual)halogen batteries present high areal capacity and satisfactory cycling stability.This work provides a new avenue for developing aqueous zinc-(dual)halogen batteries.

Enhanced selectivity of catalytic hydrogenation of halogenated nitroaromatics by interfacial effects

The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.

Regularities controlling the distribution of halogens in the Danzhai epithermal Hg-Au deposit in Guizhou and their significance

HALOGENS, as mineralizer elements, have been attracting ever increasing attention of geological workers inpetrogenetically experimental and ore-forming fluid geochemical studies. However, little research workhas been done on the contents, variation characteristics and significance of halogens in solid ores(rocks). It is found in the study of the Danzhai Hg-Au deposit that (i) variations in the contents ofhalogens and their distribution regularities in solid rocks and ores can shed light on the formation of thedeposit; and (ii) halogens can serve the function of indicator elements in search of buried orebodies. 1 Main characteristics of the ore

Simultaneous Degradation, Dehalogenation, and Detoxification of Halogenated Antibiotics by Carbon Dioxide Radical Anions

Despite the extensive application of advanced oxidation processes(AOPs)in water treatment,the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number of factors.Halogen moieties exhibit strong resistance to oxidative radicals,affecting the dehalogenation and detoxification efficiencies.To address these limitations of AOPs,advanced reduction processes(ARPs)have been proposed.Herein,a novel nucleophilic reductant—namely,the carbon dioxide radical anion(CO_(2)^(·-))—is introduced for the simultaneous degradation,dehalogenation,and detoxification of florfenicol(FF),a typical halogenated antibiotic.The results demonstrate that FF is completely eliminated by CO_(2)^(·-),with approximately 100%of Cland 46%of Freleased after 120 min of treatment.Simultaneous detoxification is observed,which exhibits a linear response to the release of free inorganic halogen ions(R^(2)=0.97,p<0.01).The formation of halogen-free products is the primary reason for the superior detoxification performance of this method,in comparison with conventional hydroxyl-radical-based AOPs.Products identification and density functional theory(DFT)calculations reveal the underlying dehalogenation mechanism,in which the chlorine moiety of FF is more susceptible than other moieties to nucleophilic attack by CO_(2)^(·-).Moreover,CO_(2)^(·-)-based ARPs exhibit superior dehalogenation efficiencies(>75%)in degrading a series of halogenated antibiotics,including chloramphenicol(CAP),thiamphenicol(THA),diclofenac(DLF),triclosan(TCS),and ciprofloxacin(CIP).The system shows high tolerance to the pH of the solution and the presence of natural water constituents,and demonstrates an excellent degradation performance in actual groundwater,indicating the strong application potential of CO_(2)^(·-)-based ARPs in real life.Overall,this study elucidates the feasibility of CO_(2)^(·-)for the simultaneous degradation,dehalogenation,and detoxification of halogenated antibiotics and provides a promising method for their regulation during water or wastewater treatment.

Halogen modified organic porous semiconductors in photocatalysis: mechanism, synthesis, and application

Photocatalysis is considered as the promising energy conversion way to resolve the issues of energy crisis and environmental pollution.As the key point of the photocatalysis,the photocatalyst determines the final conversion efficiency from solar,therefore,the composition and photoelectronic nature of which deserve to be valued.Halogen often affects immensely the intrinsic electron configuration of the matrix because of electrophilic property,and thus its topic has attracted lots of attention for photocatalytic application.In this review,halogencontained organic porous semiconductors are discussed in detailed.Firstly,the role of halogens in photocatalysis based on organic porous semiconductors are categorized.Then,the way to introduce the halogens into organic porous semiconductors and their applications in photocatalysis are reviewed.At last,the outlooks are given at the end of this paper.This review would bring new insights into the non-metal doping engineering for improving the photocatalytic performance of organic semiconductors.

Adsorption of fluorine and chlorine on Mg(0001) surface:A density functional theory investigation

The adsorption of low-coverage of F and Cl adatoms on the Mg（0001） surface was investigated using first-principles calculations based on the density functional theory（DFT）.The stability of the（2×2） structures formed by halogen atoms adsorbed at different sites was determined.The difference between the adsorption of F and Cl on Mg（0001） surface was also discussed.The calculation results show that hollow sites are the energetically most favorable at the low-coverage.It can be concluded from the Mulliken charges and density of states that electrons transfer from the substrate Mg atoms to the adatoms,which leads to the formation of adsorbate bond and further causes the stronger interaction between Mg atom and adatom.The interaction between Cl and Mg atoms is weaker than the interaction between F and Mg.

Progress in Analytical Methods of Halogenated Disinfection By-Products

Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.

N-doped ordered mesoporous carbon as a multifunctional support of ultrafine Pt nanoparticles for hydrogenation of nitroarenes

Due to the advantages of high surface areas, large pore volumes and pore sizes, abundant nitrogen content that favored the metal-support interactions, N-doped ordered mesoporous carbons are regarded as a kind of fascinating and potential support for the synthesis of effective supported cat-alysts. Here, a N-doped ordered mesoporous carbon with a high N content （9.58 wt%）, high surface area （417 m^2/g）, and three-dimensional cubic structure was synthesized successfully and used as an effective support for immobilizing Pt nanoparticles （NPs）. The positive effects of nitrogen on the metal particle size enabled ultrasmall Pt NPs （about 1.0 ± 0.5 nm） to be obtained. Moreover, most of the Pt NPs are homogeneously dispersed in the mesoporous channels. However, using the ordered mesoporous carbon without nitrogen as support, the particles were larger （4.4 ± 1.7 nm） and many Pt NPs were distributed on the external surface, demonstrating the important role of the nitrogen species. The obtained N-doped ordered mesoporous material supported catalyst showed excellent catalytic activity （conversion 100%） and selectivity （〉99%） in the hydrogenation of halogenated nitrobenzenes under mild conditions. These values are much higher than those achieved using a commercial Pt/C catalyst （conversion 89% and selectivity 90%）. This outstanding catalytic perfor-mance can be attributed to the synergetic effects of the mesoporous structure, N-functionalized support, and stabilized ultrasmall Pt NPs. Moreover, such supported catalyst also showed excellent catalytic performance in the hydrogenation of other halogenated nitrobenzenes and nitroarenes. In addition, the stability of the multifunctional catalyst was excellent and it could be reused more than 10 times without significant losses of activity and selectivity. Our results conclusively show that a N-doped carbon support enable the formation of ultrafine metal NPs and improve the reaction ac-tivity and selectivity.

Identification of Some AOX Compounds Formed in Wool Chlorination Using Model Chemicals

The AOX (adsorbable organic halogens) problem in wool shrinkproofing effluents has attracted more attention in recent years. The probable origins and structures of AOX compounds were proved by the reaction of DCCA with the model substances of different amino acid residues. The GC-MS results indicated that available chlorine could chlorinate the side chain of tyrosine, histidine and trypotophan and generate AOX load in the effluent.

Influence of the Process Conditions on the Formation of AOX Compounds during Wool Chlorine Pretreatment

Chlorination occurred simultaneously with oxidationwhen wool was treated by chlorine-containing reagents.The adsorbable organic halogens(AOX) compounds were produced by the chlorination of amino acid residues,especially tyrosine residue. The factors that might influence the reaction of dichloroisocyanuric acid (DCCA) with tyrosine residue were discussed. Higher temperature, appropriate pH value and lower concentration of chloride ion are favorable to decrease the percentage of chlorination. Determination of optimum process conditions would be helpful to control AOX compounds formation during wool chlorine pretreatment.

Inverse Halogen Bonds Interactions Involving Br Atom in the Electronic Deficiency Systems of CH3＋… Br-Y （Y--H, CCH, CN, NC）

Inverse halogen bonds interactions involving Br in the electronic deficiency systems of CH3＋...Br-Y （Y=H, CCH, CN, NC） have been investigated by B3LYP/6- 311＋＋G（d, p） and MP2/6-311＋＋G（d, p） methods. The calculated interaction energies with basis set super-position error correction of the four IXBs complexes are 218.87, 219.48, 159.18, and 143.05kJ/mol （MP2/6-311＋＋G（d, p））, respectively. The relative stabilities of the four complexes increased in the order： CH3＋ … BrCN〈CH3＋…- BrNC〈CH3＋… BrH≈CH3＋ …BrCCH. Natural bond orbital theory analysis and the chemical shifts calculation of the related atoms revealed that the charges flow from Br-Y to CH3e. Here, the Br of Br-Y acts as both a halogen bond donor and an electron donor. Therefore, compared with conventional halogen bonds, the IXBs complexes formed between Br-Y and CH3＋. Atoms-in-molecules theory has been used to investigate the topological properties of the critical points of the four IXBs structures which have more covalent content.

Alkaline Hydrolysis to Reduce the AOX Concentrations in Effluents from Chlorination Treatment of Wool

Organic halogens generated in the chlorlnatlon treatment of wool are proven to be acutely toxic to human beings. Legislation on environmental pollution has become more and more stringent in recent years. So the chlorlnation treatment is faced with disuse. Alkaline hydrolysis is adopted to reduce the AOX (Absorbable Organic Halogen) concentrations in the effluents from the chlorlnatlontreatment under 40℃ and pH values 9, 10, 11 and 12. After treatment the reduction of AOX appears approximately 65%.

Halogen Bonding or Hydrogen Bonding between 2,2,6,6-Tetramethyl- piperidine-noxyl Radical and Trihalomethanes CHX3 （X=CI, Br, I）

The halogen and hydrogen bonding complexes and trihalomethanes （CHX3, X=C1, Br, I） are between 2,2,6,6-tetramethylpiperidine-noxyl simulated by computational quantum chem- istry. The molecular electrostatic potentials, geometrical parameters and interaction energy of halogen and hydrogen bonding complexes combined with natural bond orbital analysis are obtained. The results indicate that both halogen and hydrogen bonding interactions obey the order CI〈Br〈I, and hydrogen bonding is stronger than the corresponding halogen bond- ing. So, hydrogen bonding complexes should be dominant in trihalomethanes. However, it is possible that halogen bonding complex is competitive, even preponderant, in triiodomethane due to the similar interaction energy. This work might provide useful information on specific solvent effects as well as for understanding the mechanism of nitroxide radicals as a bioprobe to interact with the halogenated compounds in biological and biochemical fields.

QSAR Study of Halogen Phenols Toxicity to Tetrahymena Pyriformis

Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter （energy of the lowest unoccupied molecular orbital （E_LUMO）, the molecular volume （V）, and the lowest negative charge （Q_min）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, -lgEC_50dependent equation calculated at the B3LYP/6-31G^＊＊ level is more advantageous than the others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from the semi-empirical PM3 method.