High Concentrations Of Cl Research Articles

Clues about wood density and trace-element variability of Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby for bioenergy use.

The interest of biofuel producers in Neotropical species that have high growth rates, slight wood density variability, and elemental composition that does not compromise the environment has increased in recent decades. We investigated the density and chemical characteristics of wood of Schizolobium parahyba var. amazonicum (Huber × Ducke) Barneby as a source for the generation of bioenergy. Apparent radial wood density profiles (X-ray densitometry (XRD)) and the elemental distribution (X-ray fluorescence (XRF)) of Cl, S, K, and Ca in the wood of nine S. parahyba var. amazonicum trees, divided into three diameter classes (I = 15.5, II = 19.5, and III = 23.5cm) were analyzed. The high heating value (HHV) of the wood samples was determined, and the energy density was estimated by the product of the HHV and the apparent density. Trees that grew better (classes II and III) produced wood with higher density. These trees showed higher concentrations of K and S, and lower concentrations of Ca and Cl. The highest Cl concentrations were observed in classes with smaller diameters. The chlorine levels met the standards for use of this wood as fuel, but the sulfur levels were higher than the threshold recommended by the ISO 17225-3:2021 guidelines, which can limit the use of the species for certain energy uses. The wood of S. parahyba var. amazonicum had interesting characteristics for the production of bioenergy due to its low density, so it can be used in the production of solid biofuels such as pellets and briquettes. Monitoring chlorine and sulfur is important, since during the combustion of biomass they are released into the atmosphere and can negatively contribute to the effects of climate change.

Contrasting apatite geochemistry between ore-bearing and ore-barren intrusions of the giant Kalmakyr gold-rich porphyry Cu deposit, Tien Shan, Uzbekistan

The Kalmakyr deposit in Uzbekistan is one of the world’s largest gold-rich porphyry Cu deposits, and mineralization was proposed to be closely associated with the emplacement of the latest intrusive phases, that is, granodiorite porphyry. However, it is still unclear which features of these ore-bearing intrusions are crucial for the enormous metal enrichment and how they correlate with magmatic fertility. In this study, we address these questions by comparing the petrological and in situ major and trace element geochemistry of apatite for the ore-bearing and ore-barren intrusions. Magmatic apatite from the ore-bearing granodiorite porphyry has higher Eu/Eu* (0.50–0.58), Sr/Y (1.09–1.64), and La/Yb (36.19–53.42) ratios than the ore-barren quartz porphyry (0.01–0.02, 0.02–0.03, and 2.01–3.75, respectively) and monzonite (0.20–0.11, 0.36–1.12, and 19.71–56.32, respectively). Moreover, the ore-bearing granodioritic magma has higher S (average of 111 ppm) and Cl (average of 8602 ppm) contents than the magma of quartz porphyry (S contents average of 9 ppm; Cl contents average of 2652 ppm) and monzonite (S contents average of 9 ppm; Cl contents average of 8483 ppm). These features collectively suggest that the ore-bearing granodiorite porphyry has relatively high oxygen fugacity, H2O, Cl, and S contents compared to those from the ore-barren intrusions. By comparing our data with the published dataset from porphyry Cu–Mo and Mo-only deposits in the world, we suggest that the high Cl content and low F/Cl ratio in magmatic apatite might be an important indicator to prospect for gold-rich porphyry Cu deposits.

Footprints in compositions, PCDD/Fs and heavy metals in medical waste fly ash: Large-scale evidence from 17 medical waste thermochemical disposal facilities across China.

Chemical compositions, polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) profiles and heavy metals (HMs) leachability of medical waste fly ash (MWFA) from 17 thermochemical treatment facilities in eight Chinese provinces were first investigated. Large-scale and extended monitoring revealed high chloride and Zn contents and similar PCDD/Fs congener profiles in MWFA. Particularly, the PCDD/Fs and HMs concentrations implied greater toxicity than that observed for municipal solid waste incinerator fly ash (MSWIFA). The maximum international toxic equivalent value of PCDD/Fs in MWFA was 40 times that of MSWIFA, and the leaching concentrations of Zn and Hg were 15 and 4 times those of MSWIFA, respectively. Notably, MWFA characteristics suggest the possibility of recycling and sustainable disposal solutions owing to the high Cl and Zn content with good recovery instead of landfill disposal. Similarities in chemical composition, PCDD/Fs homolog distribution, and water-solubility of chloride salts allows co-processing of MWFA and MSWIFA via water-washing detoxification and thermal treatment, such as that used in cement kilns. This study supplements existing literature on the characteristics and risk management of MWFA.

Effect of hydrogen on pitting corrosion of 2205 duplex stainless steel under alternating dry/wet marine environment

Stainless steels play an extremely vital role in the field of marine engineering equipment. However, stainless steel products in service are still subject to corrosion from severe environments such as alternating dry/wet condition and damage caused by hydrogen introduced during heat treatment or cathodic protection. Under alternating dry/wet marine environment, the synergistic effect of hydrogen and corrosion can influence the corrosion resistance of stainless steels dramatically. In this work, the corrosion behavior and mechanism of 2205 duplex stainless steel under alternating dry/wet marine environment are investigated before and after hydrogen charging using electrochemical testing, component characterization and morphological observation. The results show that the open circuit potential, film resistance and breakdown potential all reduce and the passive current density increases after 12 h hydrogen charging. The ratio of Fe3+ and O2−/OH− decreases. The components of the hydrogen charged passive film alter and the performance deteriorates. The number of surface pits increases after 12 h hydrogen charging and additional 10 d alternating dry/wet corrosion. The pitting potential drops much lower. Consequently, The synergistic effect of high concentrations of Cl− in the thin liquid film and hydrogen accelerates the destruction of the passive film, further reducing the corrosion resistance of stainless steels.

Low-Temperature Carburization: Ex Situ Activation of Austenitic Stainless Steel

Surface engineering of chromium-oxide-passivated alloys (e.g., stainless steels) by low-temperature infusion of interstitial solutes (carbon, nitrogen) from a gas phase requires “surface activation” by removing or perforating the passivating oxide film. We demonstrate a new approach for surface activation based on pyrolysis of a reagent powder, introduce advanced methodology to study its microstructure, and compare it to an established activation method. Rather than a bare alloy surface, stripped of its oxide, we find that an “activated” surface involves a reaction layer containing high concentrations of Cl, carbon, or nitrogen. We propose a model for the microscopic mechanism of surface activation that will enable future systematic development toward more effective process schemes.

Dark and UV-Enhanced Degradation of Dimethyl Methylphosphonate on Mesoporous CeO2 Aerogels

Our development of high surface-area mesoporous expressions of ceria (CeO2) is motivated by recent studies identifying CeO2 as one of the most reactive oxides for adsorbing and degrading toxic organophosphorus compounds, including chemical warfare simulants. We synthesize nanostructured CeO2 aerogels using a facile, scalable, and template-free sol–gel method to amplify the number of available and accessible surface sites for organophosphorus adsorption/degradation and then spectroscopically characterize the degradation of dimethyl methylphosphonate (DMMP) at the aerogel surface. The CeO2 aerogels retain high concentrations of surface-sited residual Cl from the chloride sol–gel precursors, which block DMMP binding sites and hinder the formation of surface hydroxyls (OH). We demonstrate that a simple alkaline soak removes surface-fouling Cl and creates a more OH-rich surface, thus unleashing the hydrolytic activity of the amplified CeO2 aerogel surfaces. Whereas the Cl-fouled CeO2 surface weakly and reversibly binds DMMP, the rinsed, OH-rich surface irreversibly binds DMMP and rapidly generates hydrolysis products. Exciting the CeO2 bandgap with UV light (390–400 nm) accelerates DMMP degradation and generates a higher proportion of mineralized POx products than the dark reaction. Our work marks the first-ever report of photodegradation of a chemical warfare simulant at CeO2 as well as the first report of mineralized POx formation at CeO2 at room temperature. The high surface-area CeO2 aerogels exhibit higher capacity than non-networked, nanoparticulate CeO2, thus highlighting the potential applicability of nanocrystalline CeO2 aerogels for protection against organophosphorus compounds.

Chloride binding of monosulfate hydrate (AFm) and its effect on steel corrosion in simulated concrete pore solution

The impact of monosulfate hydrate (AFm) on chloride (Cl−) binding and steel corrosion in simulated concrete pore solutions (SCPSs) was evaluated. In the SCPS with AFm added, a high concentration of Cl− promoted the Cl− binding amount per unit AFm without producing Kuzel's salt. The Cl− binding capacity of AFm could be improved by appropriately changing the amount of AFm with a constant Cl− concentration. The addition of AFm to the SCPS shortened the passivation time and created a more stable passivation film of the steel. The SO42− produced by the AFm binding with Cl− preferentially reacted with AFm to form AFt, and it affected the stability of the Friedel's salt to release Cl−. The addition of AFm raised the chloride threshold value (CTV) for steel corrosion. However, after reaching the CTV, the corrosion rate of steels increased dramatically, due to the release of the bound Cl−.

Ferro-chloro-winchite in Northwest Africa (NWA) 998 apatite-hosted melt inclusion: New insights into the nakhlite parent melt

Melt inclusions are of major significance because they can constrain the volatile abundances in magmas. Here, we report the discovery of the first melt inclusion in a martian apatite containing the first chloro-amphibole reported in Northwest Africa (NWA) 998, a sample that crystallized early from the nakhlite-source. The amphibole is also the first sodic-calcic amphibole in a nakhlite, identified as ferro-chloro-winchite (4.75 wt% Cl) by FIB-TEM. The melt inclusion is present in a euhedral, cumulus apatite grain (Cl/F = 2.11) and is surrounded by a shell of voids. Evidence indicates that the melt inclusion remained as a closed system although syn- and post-entrapment processes may have modified the chemical composition of the original trapped melt. The inclusion also contains Fe-rich, Ca-poor pyroxene and a residual silicate melt consisting of pyroxene and interstitial K-rich glass. Additionally, Cl-enriched apatite is present within the boundaries of the melt inclusion. This apatite could result from cracking of host-apatite during contraction of the melt inclusion glass or represent daughter apatite crystallizing on the walls of the inclusion. Given that Cl-enrichments are found in the host apatite outside the melt inclusion, it is inferred that a later, fluid alteration event locally modified the composition of the apatite in and/or around the melt inclusion. The calculated bulk composition of the melt inclusion is generally consistent with previous work in other nakhlites. Prior to this study, Cl-rich amphiboles have only been found within olivine- and pyroxene-hosted melt inclusions in the later-formed nakhlites. The present study thus demonstrates that (i) the nakhlites record magmatic mixing with a Cl-rich exogenous component that is absent within olivine-hosted melt inclusions in the chassignites, (ii) Cl-rich amphiboles were able to crystallize from the earliest nakhlite parent melt, and (iii) the presence of a Cl-rich fluid was not required to stabilize chloro-amphiboles. We also conclude that magmatic martian amphiboles likely stabilized at lower pressures (and temperatures) than terrestrial amphiboles due to their higher Cl contents.

Salinity responses in 24 guar genotypes are linked to multigenic regulation explaining the complexity of tolerance mechanisms in planta

AbstractGuar (Cyamopsis tetragonoloba (L.) Taub.) is an economically important, drought‐tolerant legume crop affected by moderate to high salinity. Guar has various industrial applications, including gum extracted from seeds that is widely used in the oil and natural gas industries. In this investigation, we evaluated the salinity tolerance of different guar genotypes and their relation to genetic mechanisms regulating guar responses to salinity stress. We screened 24 guar genotypes in a greenhouse lysimeter system under control (electrical conductivity (EC) = 1.46 dS m−1) and high salinity (EC = 13.65 dS m−1) treatments. Both length and biomass of shoots were significantly affected by salinity compared to roots, indicating higher shoot than root sensitivity to salinity. Twenty‐four genotypes were classified based on salt tolerance index for each trait. Tissue ion analysis revealed that roots accumulated over 10‐fold higher Na than leaves, demonstrating that guar effectively regulated the root‐to‐shoot movement of Na+. However, higher Cl concentrations in leaves than roots indicated less regulatory control of Cl− movement. Based on the morphological traits and tissue ion analysis, six genotypes (PI 164486, PI 253186, PI 26152, PI 158125, PI 179926, and PI 263698) with different responses to salinity were selected for gene expression analysis. Expression patterns of different genes showed that a complex network of component traits, including Na+ exclusion, Cl− exclusion, and tissue tolerance, regulate salinity tolerance in guar. Hence, the genetic information about different component traits will benefit guar breeders in developing new varieties that are more tolerant to salinity than current ones.

Artificial skin with fast and robust self-healing ability for durable intelligent protection of magnesium alloys

Imitating the self-healing behavior of the skin of living organisms to damage, the artificial skin with fast and robust self-healing ability that can provide durable intelligent protection for magnesium alloys was elaborately designed and fabricated in this work. The as-prepared artificial skin has two-layers, and the thin bottom layer is a hydrothermal film composed of magnesium (hydr)oxides and the thick top layer is a uniform and compact polyethyleneimine (PEI) – polyacrylic acid (PAA) polymer film that was fabricated by layer-by-layer (LBL) assembly method. The artificial skin can heal the cuts of 25 μm–120 μm within 25 min under moist atmosphere even with high concentrations of aggressive Cl-. More importantly, the skin shows exceptional self-healing robustness to various severe damage (including repeated cutting/scratching, high temperature and organic-solvent immersion). The molecular dynamics method was used to simulate the dynamic self-healing process of the artificial skin, which elucidates that the self-healing mechanism of the as-prepared artificial skin is mainly related to the special reversible interaction among polymer molecules under humidity. This work may not only boost the application of magnesium alloys in harsh environments, but also provide a novel way for durable intelligent protection of metallic materials.

Elevating pH and introducing SO42– to promote organic dye mineralization by UV/PDS process under high contents of Cl– conditions

Elevating pH and introducing SO42– to promote organic dye mineralization by UV/PDS process under high contents of Cl– conditions

Effect of salinity on the denitrification of the sulfur-based autotrophic denitrification system

This study investigated the effect of gradual salt concentration increases on the nitrogen removal performance from a sulfur-based autotrophic denitrification (SAD) process. A continuous operation reactor was used to study the adaptability of sulfur-based autotrophic denitrifying bacteria to changes in salinity. The study focused specifically on the effects of SO42− and Cl− on the activity of SAD bacteria. When the concentration of SO42− was 0∼4 ​g/L, NO3−-N was removed at more than 97%. When the concentration of SO42− increased to 15 ​g/L, the removal of NO3−-N decreased to 51%. When the concentration of NaCl was 0∼30 ​g/L, the removal rate of NO3−-N was all greater than 97%. When the concentration of NaCl increased to 80 ​g/L, the removal rate of NO3−-N decreased to 34.6%. When the NaCl concentration was 50 ​g/L, the removal rate of NO3−-N decreased to 80.59% at first, and the removal rate of NO3−-N recovered to 98% after 16 days of operation. When the NaCl concentration increased to 80 ​g/L, the NO3−-N removal rate decreased to 50%, and the reactor still could not recover its performance after long-term operation. The growth of halophilic heterotrophic bacteria with the increase of NaCl concentration leads to an increase in the abundance of Proteobacteria. The higher concentration of Cl− seriously inhibits the growth of Sulfurimonas and Thiobacillus, decreasing the effectiveness of bacteria to remove nitrogen.

Seawater Intrusion Risk and Prevention Technology of Coastal and Large-Span Underground Oil Storage Cavern

The presence of a high concentration of Cl− in saltwater will erode the structure and facilities, reducing the stability and service life of the underground oil storage cavern. In order to reduce the risk of seawater intrusion, this paper studies the risk and prevention technology of seawater intrusion based on a case study of a coastal and large-span underground oil storage cavern. A refined three-dimensional hydrogeological model that comprehensively considers permeability coefficient partitions, faults, and fractured zones are constructed. The seepage fields and seawater intrusion risks of the reservoir site in its natural state, during construction, and during operation are examined, respectively. The study quantifies the water inflow and optimizes the seawater intrusion prevention technology. The results indicate that there is no risk of seawater incursion into the cavern under natural conditions. The water inflows after excavating the top, middle, and bottom sections of the main cavern are predicted to be 6797 m3/day, 6895 m3/day, and 6767 m3/day, respectively. During the excavation period, the water supply from the water curtain system is lower than the water inflow of the cavern, providing the maximum water curtain injection of 6039 m3/day. The water level in the reservoir area decreased obviously in the excavation period, but the water flow direction is from the cavern to the sea. Additionally, the concentration of Cl− in the cavern area is less than 7 mol/m3; hereby, there are no seawater intrusion risks. When only the horizontal water curtain system is deployed, seawater intrusion occurs after 18 years of cavern operation. The concentration of Cl− in the southeast of the cavern group exceeds 50 mol/m3 in 50 years, reaching moderate corrosion and serious seawater intrusion. In addition to the horizontal curtain above the cavern, a vertical water curtain system could be added on the southeast side, with a borehole spacing of 10 m and extending to 30 m below the cavern group. This scheme can effectively reduce seawater intrusion risk and extend the service life of the cavern. The findings of this research can be applied as guidelines for underground oil storage caverns in coastal areas to tackle seawater intrusion problems.

Effect of oil displacement agent on corrosion behavior of NaCl - Alkali/ Surfactant/ Polymer flooding pipeline steel

The research examined the effect of oil displacement agent (Hydrolyzed polyacrylamide, Sodium petroleum sulfonate, NaCl) on corrosion behavior of 20# steel in simulated NaCl ASP flooding solution. Scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were performed to investigate the corrosion mechanism of oil displacement agent on carbon steel. The results demonstrated HPAM (hydrolyzed polyacrylamide) and SPS (sodium petroleum sulfonate) can be adsorbed on the surface of carbon steel to played a role in corrosion inhibition. For-HPAM, the corrosion inhibition rate decreases at high concentrations, which was ascribed to the saturation of adsorption amount and the thinning of corrosion product layer at higher concentrations. For-SPS, the formation of hemi-micellar aggregates caused desorption of the inhibitor from the metal/solution interface at higher concentrations. For -NaCl, NaCl promoted the occurrence of corrosion. Although the adsorption of oxygen on the surface of carbon steel was inhibited by a higher concentration of Cl−, a corrosion cell was formed under the action of the adsorption layer of HPAM and SPS, which promoted localized corrosion.

Using apatite to differentiate metallogenic potential and environment of granitic rocks: A case study from the Tongshanling W-Sn-Cu-Pb-Zn ore field, Nanling Range (South China)

The Tongshanling ore field is one of the most representative W–Sn–Cu–Pb–Zn polymetallic deposits in the central-western Nanling Ore Belt, which developed multiple mineralization types, including Cu–Pb–Zn (Tongshanling), W–Sn (Weijia), Pb–Zn (Jiangyong), and Mo (Yulong) deposits. Here, we analyzed apatite from the Tongshanling granodiorite and the Weijia granite porphyry, integrating major and trace elements, U–Pb dating, and Nd isotopic analyses to compare the difference in geochronology, magma source, redox environment, and evolution between the Tongshanling and Weijia deposit. The U–Pb dating of the Tongshanling and Weijia apatite samples yield a lower intercept age of 166.2 ± 11.3 Ma (1σ, MSWD = 0.22) and 160.87 ± 8.92 Ma (1σ, MSWD = 0.44) on Tera-Wasserburg diagrams, respectively. The 147Sm/144Nd and 143Nd/144Nd ratios of the Tongshanling apatite samples are 0.136769–0.182878 and 0.512159–0.512246, respectively, with corresponding εNd (t = 166 Ma) ranging from −8.32 to −6.60, suggesting that the Tongshanling granodiorite was produced by partial melting of metaigneous rocks in the deep crust. The Tongshanling apatite shows a right-inclined REE pattern, while the Weijia apatite displays a “V” type REE pattern. The Tongshanling apatite shows higher Eu/Eu* values, and lower Mn and Ce/Ce* values than the Weijia apatite, indicating that the former formed in higher magmatic oxidation state while the latter formed in more reduced conditions. The granodiorite in the Tongshanling deposit is characterized by a lower degree of fractionation than the granite porphyry in the Weijia deposit, of which the Weijia apatite has lower Sr, Mg contents, and higher Y contents. Furthermore, apatite from Cu-bearing granites exhibits lower F/Cl ratios compared to those from W-bearing granites in the South China Block. In the Tongshanling area, apatite from the Tongshanling granodiorite has higher Cl contents than the Weijia apatite, indicating that the crustal basement of the Tongshanling area was affected by the high Cl fluid derived from the Proterozoic oceanic subduction and remelted to form granite in the Mesozoic, while the Weijia granite porphyry formed from remelting of a sedimentary source. The Tongshanling granodiorite and Weijia granite porphyry with different degrees of fractionation, magma source, and halogens contents can be effectively distinguished by the geochemistry of apatite. The difference in trace elements (Sr, Y, Mg, and REE) and isotopes of apatite can be applied to the identification of different types of ore-bearing granites in the Nanling Range.

Geochemical characteristics of apatite and amphibole within the granitic intrusions from the Suyunhe Mo deposit, Xinjiang province, NW China: Insights into petrogenesis and mineralization potential

Textural and compositional variations in apatite and amphibole from mineralized granite (G), granite porphyry (GP), granodiorite porphyry (GDP), and barren tonalite porphyry (TDP) in the Suyunhe ore district, Xinjiang province, NW China revealed differences in their petrogenesis, magmatic properties and mineralization potentials. The higher Cl contents (0.09–0.18 wt%) and Cl/F ratios of apatite, and the higher Mg/(Mg + Fe2+) ratios (0.54–0.62) of amphibole in the barren TDP indicate that the parental magma was mainly generated via melting of the lithospheric mantle. In contrast, the parental magmas of the GDP, G, and GP were mainly derived from melting of the juvenile lower crust. The enrichment of Mn, Y, and heavy rare earth elements (HREEs), depletion of Sr, and strong negative Eu anomalies of the apatite from the GP indicate that it underwent a high degree of fractional crystallization. Moreover, the reverse core-to-rim compositional variations in REE and Sr contents and the La/Y ratios observed in some of the apatite grains, as well as the distinct differences in the major-element compositions (e.g., CaO, MnO, SiO2, and Ce2O3) of the individual zones within single apatite grains, indicate magmatic mixing. The calculated magmatic viscosities (Logη = 4.8–5.0 Pas) at Suyunhe remained below the average value for granitic melts (mostly Logη > 5 Pas) at the same temperature. These results support the hypothesis that low-viscosity magma (e.g., Logη < 5 Pas) may be essential for the formation of porphyry Mo deposits. The physicochemical conditions (including temperature, pressure, and H2O content) estimated based on the amphibole in the mineralized intrusions indicate the existence of a deep magma chamber with a large volume, which continuously released volatiles (e.g., fluorine and water) and effectively reduced the viscosity of the magma.

Appraisal of groundwater quality for drinking and irrigation suitability using multivariate statistical approach in a rapidly developing urban area, Tirunelveli, India.

The quantitative and qualitative stress on groundwater resources has been witnessed across the globe. The current study assesses the groundwater quality of Tirunelveli district which faces the hazard of groundwater contamination through seepage of toxins, considering the open dumping ofhuge volumes of solid waste. The findings from this study confirmed the presence of more than 20% samples in the "poor to very poor" quality with high concentrations of TDS, Cl-, and NO3-, unfit for drinking, and other domestic purposes. The spatial distribution of TDS and NO3- highlighted the potentialimpact of solid waste dumping in the nearby landfill sites. K-means hierarchical clustering and multivariate analysis suggested that salinization and nitrate pollution was highly influenced by anthropogenic sources in comparison to geogenic sources. Rock water interaction and evaporation processes emerged as the two major dominant natural mechanisms controlling the groundwater chemistry. Four hydro-chemical facies were identified in the order of Ca-HCO3 > Ca-Mg-Cl > Na-Cl > mixed Ca-Na-HCO3. Thus, this study creates an urgent need of mitigation measures towards curbing and management of solid waste disposal and hence, the potential hazard ofcontaminant seepage into the groundwater.

Corrosion behavior on carbon steel in a simulated soil solution under the interaction effect of chloride and bicarbonate ions

The effect of HCO3− and Cl− on the corrosion behavior of Q345 carbon steel in soil simulated solutions was investigated through electrochemical and surface characterizations. The results show that the sample behaves with active dissolution state in low concentration of Cl− solution while pseudo passivation of sample is observed in high concentration of Cl− solution. However, in solutions containing low concentration of HCO3−, the addition of high concentration Cl− does not result in the pseudo passivation of sample due to the formation of discontinuous film, which increases the corrosion rate. In addition, in solution containing high concentration of HCO3−, the addition of high concentration Cl− leads to much higher increase of corrosion rate. The deep corrosion pit is observed on the matrix due to the rapid rupture of FeCO3 film and the sufficient development of pitting.

Volatile evolution of magmas associated with the Bairong deposit, Tibet, and implications for porphyry Cu-Mo mineralization

Volatiles are considered to play an important role in porphyry Cu mineralization, and high apatite S and Cl contents are often used to distinguish fertile magma systems from barren ones in the subduction zone. However, magmatic volatile evolution and its implications in post-collisional porphyry deposits remain enigmatic. To address this issue, we conducted zircon U-Pb dating and Hf isotope, and zircon and apatite chemical compositions of multi-stage magmatic rocks from the Bairong post-collisional porphyry Cu-Mo deposit in the Gangdese belt, Tibet. The magmatic rocks included pre-mineralized porphyritic monzogranite and biotite monzogranite, syn-mineralized monzogranite porphyry, and post-mineralized dacite porphyry that formed in 14.1–12.7 Ma, ca. 12.1 Ma, and 11.8–11.6 Ma, respectively. All these intrusions have depleted zircon Hf isotope (εHf(t) = 1.7–8.0, 3.7–9.0, 3.3–9.7 for pre-, syn-, and post-mineralized intrusions, respectively) together with the research results of contemporaneous magmatic rocks in the adjacent area, suggesting that the multi-stage intrusions at Bairong are derived from a cogenetic magma chamber in post-collisional extension setting. All the intrusions have similar zircon CeN/CeN*, EuN/EuN* ratios with average ΔFMQ values of 2.1 – 2.6, together with the high apatite EuN/EuN* ratios and low Ga concentrations, implying that their magmas are all oxidized. These intrusions have zircons (10,000 × EuN/EuN*) /Y all > 1 and Ce/Nd/Y mostly > 0.01, and obtain low average titanium-in-zircon temperatures of 659 to 714 °C, which indicate their magmas are hydrous. Apatite Cl contents decrease, combined with the drop of apatite XCl/XOH and the surge of XF/XCl ratios from pre- to syn-mineralized intrusions, possibly indicating that fluid exsolved from magma at the syn-mineralization stage. The apatite SO3 contents in these different-stage intrusions, however, are almost unchanged. Combined with previous studies, the buffering effect of magmatic anhydrite maintains the stability of magma S content, which together with fluid exsolution leads to the S-Cl decoupling. Consequently, we conclude that the oxidized and hydrous magma with effective fluid exsolution is a critical control on the formation of Bairong porphyry Cu-Mo mineralization. Considering the wide variations of apatite Cl contents and the occurrences of S-Cl decoupling, simple application of high apatite SO3 and Cl contents to distinguish the ore-forming and barren systems in the post-collisional porphyry system should be cautious.

The degradation of municipal solid waste incineration leachate by UV/persulfate and UV/H2O2 processes: The different selectivity of SO4•- and •OH

In this work, the different selectivity of SO4•- and •OH towards municipal solid waste incineration leachates (MSWILs) was studied by a comparative study of UV/persulfate (PS) and UV/H2O2. Results showed SO4•- preferentially mineralized carbon atoms of higher average oxidation state, while •OH showed a two-stage mechanism of partial oxidation and mineralization successively. Electron spin resonance (ESR) analysis showed SO4•- had superior selectivity towards MSWILs than •OH, and Fe(II) would significantly affect the selectivity via forming Fe-MSWILs complex. As the consequence, Fe(II) showed slightly negative effect on UV/PS, but greatly enhanced the performance of UV/H2O2/Fe(II). High concentration of Cl- affected the degradation of non-fluorescent substances by UV/PS, while SO42- and NO3- showed no effect. In contrast, anions showed no effect on UV/H2O2. In addition, •OH preferentially attacked large molecules, but SO4•- showed no selectivity. This study further revealed the selectivity of SO4•- and •OH in the treatment of hypersaline wastewater, and provided theoretical support for the development of targeted technology.