Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge:evidence from sulfide chronology

The Yuhuang hydrothermal field(YHF)is located between the Indomed and Gallieni fracture zones near the top of the off-axis slope on the south rift wall of Segment 29 on the ultraslow Southwest Indian Ridge(SWIR).Previous studies have shown that sulfides in the YHF formed during different mineralization episodes and the YHF has the greatest potential for the formation of large-scale seafloor massive sulfide deposits.However,the sulfide chronology and hydrothermal activity of the YHF remain poorly constrained.In this study,mineralogical analyses and 230Th/U dating were performed.Hydrothermal activity may start about(35.9±2.3)ka from the southwest part of the YHF and may cease about(708±81)a ago from the northeast part of the YHF.The 74 nonzero chronological data from hydrothermal sulfide samples provide the first quantitative characterization of the spatial and temporal history along the SWIR.Hydrothermal activity in the SWIR has been relatively active over the past20 ka.In contrast,between 40 ka and 100 ka,hydrothermal activity was relatively infrequently and short in duration.The maximum activity occurred at 15–11 ka,9–7 ka,6–0.2 ka.There was a slight positive correlation between the maximal age and estimated surface area or estimated tonnage.The minimum mass accumulation rate of YHF is about 278 t/a,which is higher than most HFs related to ultramafic systems.The ultraslow spreading SWIR has the greatest potential to form large-scale seafloor massive sulfides(SMS)deposits.The results of this study provide new insights into the metallogenic mechanism of hydrothermal sulfides along ultraslow-spreading ridges.

Mechanism of mechanical activation for sulfide ores

Structural changes for mechanically activated pyrite,sphalerite,galena and molybdenite with or without the exposure to ambient air,were systematically investigated using X-ray diffraction analysis(XRD),particle size analysis,gravimetrical method, X-ray photo-electron spectroscopy(XPS)and scanning electron microscopy(SEM),respectively.Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers,several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained.For brittle sulfide ores with thermal instability,and incomplete cleavage plane or extremely incomplete cleavage plane,the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation.The effects of mechanical activation are apparent.For brittle sulfide ores with thermal instability,and complete cleavage plane,the mechanism of mechanical activation is that a great amount of surface reactive sites are formed,and lattice deformation happens during their mechanical activation.The effects of mechanical activation are apparent.For brittle sulfide ores with excellent thermal stability,and complete cleavage plane,the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation.The effects of mechanical activation are apparent. For sulfide ores with high toughness,good thermal stability and very excellent complete cleavage plane,the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation,but the lattice deformation ratio is very small.The effects of mechanical activation are worst.

Design,Synthesis and Antitumor Activity of Fluoroquinolone C3 Heterocyclic Bis-oxadiazole Methylsulfide Derivatives Derived from Levofloxacin

To discover an efficient route for the shift from an antibacterial fluoroquinolone to an antitumor one based on the mechanistic similarities between targeting topoisomerases and the eukaryotic ones,two series of the title compounds,C3 bis-oxadiazole methylsulfides 6a―6h and corresponding dimethylpiperazinium iodides 7a―7h derived from levofloxacin 1 were designed and synthesized.Their in vitro antiproliferative activities against Chinese hamster ovary cell line（CHO）,murine leukemia cell line（L1210） and human leukocytoma cell line（HL60） were evaluated by MTT assay,and inhibitory effect on DNA topoisomerase IIα was also measured by means of densitometric assay.

Antitumor Activity of Diallyl Sulfide in Two-StageMouse Skin Model of Carcinogenesis

It has been reported that diallyl sulfide (DAS), a sulfur-containing volatile compound in garlic (Allium sativum ), exerts anticarcinogenic activity in various rodent tumor models. In the present study, the antitumor property of DAS was tested in Swiss albino mice in the two steqe initiation-promotion mouse skin carcinogenesis. Skin cancers were initiated topically with a single subcarcinOgenic dose (52μg) of 7, 12-dimethyl benz (a) anthracene (DMBA). Promotion was performed by twice weekly applications of 12-O-tetradecanoyl phorbol-13-acetate (TPA) at a dose of 5μg/animal for 32 weeks. DAS was applied topically (250μg/animal) thrice weekly for 3 weeks for anti-initiating and 1 h prior to each promotion treatment for anti-promoting studies. The results showed that the treatment schedule of DAS can effectively delay the onset of tumorigenesis and reduce the cumulative number of tumors and the average number of tumors per mouse. In groups in which DAS applied prior to initiation or promotion, a significant population of the aniinals remained tumor-free till the termination of experiment. These findings suggest that DAS can effectively inhibit chemically induced mouse skincarcinogenesis.

Preparation of Low Cost Activated Carbon from Deactivated Resin Catalyst for Methyl Tert-Butyl Ether Synthesis and Its Application in Dimethyl Sulfide Adsorption with Transition Metal Impregnation

In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activated carbon was characterized in detail. After loading various transition metals, including Cu^(2+), Ag+, Co^(2+), Ni^(2+), Zn^(2+), and Fe^(3+) via the ultrasonic-assisted impregnation method, a series of metal-loaded adsorbents(xM-AC) were obtained and their dimethyl sulfide(DMS) adsorption performance was investigated in a batch system. Among these adsorbents, 15Cu-AC presented a superior DMS adsorption capacity equating to 58.986 mg/g due to the formation of S-M(σ) bonds between Cu^(2+) and sulfur atoms of DMS as confirmed by the Raman spectra and kinetic study.

Recent update on electrochemical CO_(2)reduction catalyzed by metal sulfide materials

Seeking and developing efficient CO_(2)reduction reaction(CO_(2)RR)electrocatalysts is a hot topic in this era of global warming.Among material candidates for sustainable and cost-effective applications,metal sulfides have attracted attention as promising nature-inspired materials due to multiple adsorption sites which are enhanced by the covalent character of sulfur.This article summarizes the current status regarding the utilization and development of metal sulfide materials as CO_(2)RR electrocatalysts.First,the research background and basic principles of electrochemical CO_(2)RR are introduced.Next,an overview of the main obstacles to developing efficient CO_(2)RR electrocatalysts is presented.The section is followed by a summary of the empirical evidence supporting the application of metal sulfides as CO_(2)RR electrocatalysts beside nature-inspired motivation.The summary of synthesis methods of various metal sulfides is also presented.Furthermore,the paper also highlights the recent works on metal sulfide as efficient CO_(2)RR including the undertaking strategy on the activity enhancement,and finally,discusses the challenges and prospect of metal sulfides-based CO_(2)RR electrocatalysts.Despite recent efforts,metal sulfides remain relatively unexplored as materials for CO_(2)RR electrocatalytic applications.Therefore,this review aims to stimulate novel ideas and research for improved catalyst designs and functionality.

Catalytic hydrolysis of carbonyl sulfide over modified coal-based activated carbons by loading metal

A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide(COS) .The influences of the calcination temperature,additive content(2.5%-10.0%Fe2O3,mass fraction) and the basic density of the activation process were thoroughly investigated.The surface of catalysts was characterized by Boehm titration.The products were characterized by scanning electron microscopy(SEM) ,X-ray diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS) .The results show that catalysts with 2.5%-5.0%Fe2O3 after calcining at 500℃have superior activity.The conversion rate of COS increases with increasing the relative density of basic capacity loaded onto activated carbon(AC) ,and the activity follows the order:KOH>Na2CO3>NaHCO3.Boehm titration data clearly show that the total acidity increases(from 0.06 to 0.48 mmol/g) and the basic groups decrease(from 0.78 to 0.56 mmol/g) after COS hydrolysis and H2S adsorption.The XPS results show that the product of H2S may be absorbed by the interaction with metal compounds and O2 to form sulfate(171.28 eV) and element sulfur(164.44 eV) ,which lead to catalysts poisoning.

Catalytic effect of activated carbon on bioleaching of low-grade primary copper sulfide ores

The catalytic effect of activated carbon on the bioleaching of low-grade primary copper sulfide ores using mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was investigated. The results show that the addition of activated carbon can greatly accelerate the rate and efficiency of copper dissolution from low-grade primary copper sulfide ores. The solution with the concentration of 3.0 g/L activated carbon is most beneficial to the dissolution of copper. The resting time of the mixture of activated carbon and ores has an impact on the bioleaching of low-grade primary copper sulfide ores. The 2 d resting time is most favorable to the dissolution of copper. The enhanced dissolution rate and efficiency of copper can be attributed to the galvanic interaction between activated carbon and chalcopyrite. The addition of activated carbon obviously depresses the dissolution of iron and the bacterial oxidation of ferrous ions in solution. The lower redox potentials are more favorable to the copper dissolution than the higher potentials for low-grade primary copper sulfide ores in the presence of activated carbon.

Experimental Design Technique on Removal of Hydrogen Sulfide using CaO-eggshells Dispersed onto Palm Kernel Shell Activated Carbon：Experiment,Optimization,Equilibrium and Kinetic Studies

This study presents the use of chicken eggshells waste utilizing palm kernel shell based activated carbon（PKSAC） through the modification of their surface to enhance the adsorption capacity of H2S. Response surface methodology technique was used to optimize the process conditions and they were found to be： 500 mg/L for H2S initial concentration, 540 min for contact time and 1 g for adsorbent mass. The impacts of three arrangement factors（calcination temperature of impregnated activated carbon（IAC）, the calcium solution concentration and contact time of calcination） on the H2S removal efficiency and impregnated AC yield were investigated. Both responses IAC yield（IACY, %） and removal efficiency（RE, %） were maximized to optimize the IAC preparation conditions. The optimum preparation conditions for IACY and RE were found as follows： calcination temperature of IAC of 880 ℃, calcium solution concentration of 49.3% and calcination contact time of 57.6 min, which resulted in 35.8% of IACY and 98.2% RE. In addition, the equilibrium and kinetics of the process were investigated. The adsorbent was characterized using TGA, XRD, FTIR, SEM/EDX, and BET. The maximum monolayer adsorption capacity was found to be 543.47 mg/g. The results recommended that the composite of PKSAC and Ca O could be a useful material for H2S containing wastewater treatment.

Improved hemimorphite flotation using xanthate as a collector with S(Ⅱ) and Pb(Ⅱ) activation

The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation results indicated that hemimorphite floats when the S(Ⅱ)–Pb(Ⅱ)–xanthate process is used; a maximum recovery of approximately 90% was obtained.Zeta-potential,contact-angle,scanning electron microscopy–energy-dispersive spectrometry(SEM–EDS),and diffuse-reflectance infrared Fourier transform spectroscopy(DRIFTS) measurements were used to characterize the activation products on the hemimorphite surface and their subsequent interaction with sodium butyl xanthate(SBX).The results showed that a Zn S coating formed on the hemimorphite surface after the sample was conditioned in an Na2 S solution.However,the formation of a Zn S coating on the hemimorphite surface did not improve hemimorphite flotation.With the subsequent addition of lead cations,Pb S species formed on the mineral surface.The formation of the Pb S species on the surface of hemimorphite significantly increased the adsorption capacity of SBX,forming lead xanthate(referred to as chemical adsorption) and leading to a substantial improvement in hemimorphite flotation.Our results indicate that the addition of lead cations is a critical step in the successful flotation of hemimorphite using the sulfidization–lead ion activation–xanthate process.

Oil-soluble Ni-Mo sulfide nanoparticles and their hydrogenation catalytic properties

Oil-soluble bimetallic Ni-Mo sulfide nanoparticles（NiMoS） with narrow size distribution were successfully synthesized through a composite-surfactants-assisted-solvothermal process.The surface functionality and lipophilicity of the Ni-Mo sulfides were shown by transmission electronic microscopy,Fourier transform infrared and ultraviolet spectroscopy.The as-prepared Ni-Mo sulfides supported on activated carbon（NiMoS/AC） exhibited enhanced catalytic activity towards naphthalene hydrogenation instead of cracking.For comparison,CoMoS/AC and MoS2/AC catalysts were also prepared through similar procedures,and it was found that their catalytic performance decreased in the order of NiMoS/AC〉CoMoS/AC〉MoS2/AC.Furthermore,the activity of the bimetallic NiMoS nanocatalyst can be effectively tuned via variation of the atomic ratio of Ni/（Ni＋Mo）.

Spontaneous combustion tendency of fresh and pre-oxidized sulfide ores

Three representative sulfide ore samples were collected from typical metal mines,and their corresponding pre-oxidized products were obtained under nature environment.The thermal behaviors of each sample at heating rates of 5,10,15 and 20 °C/min in air flow from ambient temperature to 800 °C were studied by simultaneous thermal analysis and the TG/DSC curves before and after the pre-oxidation were compared.By the peak temperature of DTG curves,the whole reaction process for each sample was divided into different stages,and the apparent activation energies were calculated by the Ozawa-Flynn-Wall method.The results show that the reaction process of each sample after pre-oxidation is more complex,with quicker reaction rates,fewer heat production quantities,and higher or lower ignition-points.The apparent activation energies decrease from 364.017-474.228 kJ/mol to 244.523- 333.161 kJ/mol.Therefore,sulfide ores are more susceptible to spontaneous combustion after the pre-oxidation.

A Novel Sulfided Mo/C Catalyst for Direct Vapor Phase Carbonylation of Methanol at Atmospheric Pressure

The direct carbonylation of methanol, without any halide in the feed as apromoter, is presented. A series of Mo catalysts supported on activated carbon, γ-Al_2O_3 and SiO_2were prepared. The results show that the support greatly affects the Mo catalyst in the directvapor-phase carbonylation of methanol, and activated carbon is the best supports of the investigatedsupports. In addition, the relationships between adsorptions of NH_3 and CO and carbonylation ofmethanol were investigated. A novel sulfided Mo/C catalyst had high activity and selectivity for thevapor phase carbonylation of methanol to methyl acetate without the addition of a CH_3I promoter tothe feed. The reaction conditions were optimized at a reaction temperature of 573 K, a methanolconcentration of 23 mol% and a carbon monoxide space velocity of 3,000 L/(kg·h). Under theseoptimal conditions a methanol conversion of 50%, carbonylation selectivity of 80 rnol%, andspace-time yield of 8.0 mol/(kg·h) were obtained. The active phase of this novel sulfided Mo/Ccatalyst is the non-crystalline phase, and the active component is present as MoS_(2.5) on thesurface of the activated carbon.

ACTIVATION MECHANISM OF AlCl_3 DURING THE LEACHING OF Cu-Ni ORE WITH FeCl_3

After Cu-Ni ore powder pre-soaked in AlCl3 solution.the leaching ratios of copper andnickel can increase obviously.By X-ray diffraction analyses,electron energy spectrum analysesand electrochemical experiments,it is affirmed that,the activation of aluminum ion includestwo aspects:one is the surface change of the ore by the absorption of hydrolysates,and the oth-er is the change of semiconductor characteristics of the metal sulfides by impurity aluminum ionentering the lattice,so that leaching reactions are accelerated.

Structural and Characteristics of Manganese Doped Zinc Sulfide Nanoparticles and Its Antibacterial Effect against Gram-Positive and Gram-Negative Bacteria

The Manganese doped zinc sulfide nanoparticles of the cubic zinc blende structure with the average crystallite size of about 3.56 nm were synthesized using a coprecipitation method using Thioglycolic Acid as an external capping agent for surface modification. The ZnS:Mn2+ nanoparticles of diameter 3.56 nm were manufactured through using inexpensive precursors in an efficient and eco-friendly way. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy are used to examine the structure, morphology and chemical composition of the nanoparticles. The antimicrobial activity of (ZnS:Mn2+) nanocrystals was investigated by measuring the diameter of inhibition zone using well diffusion mechanism versus two various bacterial strains. The technique of microorganism inactivation was considered as sorts-dependent. Bacillus subtilis showed the largest antibacterial sensitivity (35 mm) to ZnS: Mn2+ nanoparticles at a concentration (50 mM) whereas Escherichia coli offered maximum zone of inhibition (20 mm) at the same concentration. In this study, the results indicated that ZnS:Mn2+ nanoparticles were found to have significant antibacterial activity against Gram-negative (E. coli) and Gram-positive (Bacillus subtilis) bacteria.

Ferroptosis-inducing inorganic arsenic(II)sulfide nanocrystals enhance immune activation

Arsenic(II)sulfide is a stable inorganic arsenic compound with a different valence from arsenic trioxide,and has been widely applied to treat various diseases with low toxic side effects for a long time.However,its low solubility and complicated formulations restrict its further applications in modern medical industry.Meanwhile,as the tumour with the highest incidence rate among women,the low recurrence risk of breast cancer has been confirmed to be closely related to the high infiltration of immune cells.Herein,we synthesized and filtered novel biocompatible PEGylated arsenic(II)sulfide nanocrystals AsS@PEG with a size of 93.14±0.49 nm by the gel method,which displayed excellent anticancer and immune activation activity in breast cancer model.Proteomic analysis suggested that the AsS@PEG induce ferroptosis in cancer cells and further activate antitumour immune responses via B-cell lymphoma 9-like(BCL9L)protein inhibition.Furthermore,mechanism studies revealed notable glutathione peroxidase 4(GPX4)downregulation in cancer cells,dendritic cells(DCs)maturation and subsequent effector CD8^(+)T-cells production induced by the AsS@PEG in the tumour microenvironment.This study highlights biocompatible arsenic(II)sulfide nanocrystals that induce ferroptotic cell death and activate antitumour immune responses,providing insights into the path towards the immunotherapy assisted chemotherapy for breast cancer.

氨离子对水钴矿硫化浮选的影响及其机理

引入氨离子强化主要的氧化钴矿物(水钴矿)的硫化,使其浮选回收率从不到20%显著提高到70%以上。微浮选和傅立叶变换红外分析表明,氨离子增强黄药的吸附强度,从而提高水钴矿的浮选回收率。Zeta电位、ICPOES和XPS测试进一步表明,水钴矿表面的钴可通过形成氨配合物而转移到液相中,从而增加矿物表面的硫吸附位点,促进硫化。这项研究将有助于更好地理解水钴矿的浮选行为,并为高效回收氧化钴矿提供有价值的参考。

贵州某硫化铅锌矿选矿试验研究

贵州某硫化铅锌矿的矿物共生关系复杂,嵌布粒度大小不均匀。为实现矿石中有价金属铅和锌的高效利用,采用优先浮选工艺,并采用新型高效环保锌活化剂X-43替代硫酸铜,通过铅锌浮选条件试验确定适宜的选矿工艺流程和药剂制度。试验结果表明,对于铅品位4.23%、锌品位8.02%的原矿,在磨矿细度为-0.074 mm占80%的条件下,优先选铅时采用1次粗选、1次扫选和铅粗精矿再磨至-0.045 mm占65.5%后3次精选,可获得铅品位50.19%、回收率65.33%的铅精矿;选铅尾矿经活化剂X-43活化后,采用1次粗选、2次扫选和2次精选选锌;经全流程闭路试验可得到铅品位为57.63%、回收率为80.50%的铅精矿,以及锌品位为49.62%、回收率为92.52%的锌精矿,尽可能地实现了铅和锌的有效回收。研究结果可为新型高效锌活化剂X-43的应用和同类型铅锌矿石开发利用提供借鉴。

活性炭吸附塔产生硫化氢的原因及解决措施研究

某矿山水处理工序采用“电石渣中和过滤—滤液活性炭吸附除油”的基本流程,针对其活性炭吸附塔产生硫化氢这一实际问题开展了分析研究,结果表明塔内SRB的生长繁殖是产生硫化氢气体的直接原因,并且得出了SRB菌种的来源为生活污水返回所致。从活性炭吸附后的水体中分离出一株SRB菌株,该菌的生长繁殖受到pH值、温度、氧气、Fe^(2+)、碳源等环境因素的影响,其中pH值和温度是影响SRB生长繁殖的重要因素。结合现场实际,对比分析了可采取的治理措施及优缺点,通过热处理治理有效抑制了细菌的生长,达到了治理效果。

新型含丁烯酸内酯基三氟乙基硫醚(亚砜)类化合物的设计、合成与杀螨活性

为寻找高活性杀螨化合物,以sulfiflumin为先导化合物,保留4-甲基-2-氟-5-(2,2,2-三氟乙硫基)苯胺活性基团,通过其与氯乙酰乙酸乙酯成环合成三氟乙基硫醚丁烯酸内酯的核心骨架C1,再对核心骨架进行氧化、氯代或溴代,以及将内酯环改造为硫内酯环及二硫代酮酯环得到C2~C87个化合物,采用1H NMR、^(13)C NMR和HRMS手段对其结构进行了表征。生物活性测试数据表明,目标化合物在100 mg/L质量浓度下具有一定的杀螨活性,尤其是对朱砂叶螨Tetranychus cinnabarinus卵孵化的抑制活性较高(校正孵化抑制率67%~93%);此外,化合物C3对二斑叶螨Tetranychus urticae成虫的的校正死亡率达100%。该研究可为丁烯酸内酯基三氟乙基硫醚(亚砜)衍生物和氟吡呋喃酮衍生物的设计和改造提供研究思路,对探究该类化合物的生物活性具有参考意义。