Chloride Source Research Articles

Bismuth Oxyhalides for NOx Degradation under Visible Light: The Role of the Chloride Precursor

Photocatalysis is a green technology for tackling water and air contamination. A valid alternative to the most exploited photocatalytic material, TiO2, is bismuth oxyhalides, which feature a wider bandgap energy range and use visible radiation to attain photoexcitation. Moreover, their layered structure favors the separation of photogenerated electron–hole pairs, with an enhancement in photocatalytic activity. Controlled doping of bismuth oxyhalides with metallic bismuth nanoparticles allows for further boosting of the performance of the material. In the present work, we synthesized Y%Bi-doped BiO(Cl0.875Br0.125) (Y = 0.85, 1, 2, 10) photocatalysts, using cetyltrimethylammonium bromide as the bromide source and varying the chloride source to assess the impact that both length and branching of the hydrocarbon chain might have on the framing and layering of the material. A change in the amount of the reducing agent NaBH4 allowed tuning of the percentage of metallic bismuth. After a thorough characterization (XRPD, SEM, TEM, UV-DRS, XPS), the photocatalytic activity of the catalysts was tested in the degradation of NOx under visible light, reaching a remarkable 53% conversion after 3 h of illumination for the material prepared using cetylpyridinium chloride.

α-Amylase and cellulase production by novel halotolerant Bacillus sp.PM06 isolated from sugarcane pressmud.

A novel Bacillus sp.PM06 isolated from sugarcane waste pressmud was tested for extracellular α-amylase and cellulase enzyme production. The effect of different substrates, nitrogen sources, pH, and temperature on growth and extracellular enzyme production was examined. Bacillus sp.PM06 was able to grow with starch and carboxymethyl cellulose (CMC) as a sole source of carbon and ammonium chloride was found to be the best nitrogen source. Maximum enzyme production was obtained at 48H for both α-amylase and cellulase. The optimal condition for measuring enzyme activity was found to be pH 5.5 at 50°C for α-amylase and pH 6.4 at 60°C for cellulase respectively. It was found that Bacillus sp.PM06 exhibited halotolerance up to 2M Sodium chloride (NaCl) and Potassium chloride (KCl). The isolate could produce α-amylase in the presence of 2M NaCl and 1M KCl. However, the strain produced cellulase even in the presence of 2M NaCl and KCl. Concomitant production of both enzymes was observed when the medium was supplemented with starch and CMC. A maximum of 31±1.15U/mL of amylase and 15±1.5U/mL of cellulase was produced in 48H. The enzyme was partially purified by Ammonium sulphate (NH4 )2 SO4 precipitation with 2.2 and 2.3-fold purification.

Direct Oxidation of Aryl Malononitriles Enabling a Copper-Catalyzed Intermolecular Alkene Carbochlorination.

A copper-catalyzed carbochlorination of alkenes with aryl malononitriles and chloride is disclosed. This net oxidative transformation proceeds with activated and unactivated alkenes with moderate to excellent yields. Mechanism experiments suggest addition of the malononitrile radical to form a secondary carbon radical which is intercepted by a chloride source. The resultant products can be transformed into biologically important γ-lactones in one further step.

Aerosol and Gas Phase Concentrations from an Adapted Annular Denuder System in a Broiler Housing Facility

HighlightsAn adapted annular denuder system (ADS) was implemented in a broiler facility to measure secondary aerosols.Results show that secondary aerosols were not always associated with ammonium or ammonia.Chloride aerosols were significant in comparison to other species and were present at consistent concentrations.This study concludes that the chloride source was the feed in the feeding pans.Abstract. Fine particulate matter (PM2.5) is present in animal housing facilities from both primary and secondary sources. Measuring secondary aerosols in harsh environments with high gas and particulate concentrations, such as poultry housing facilities, is an ongoing challenge. This study presents the results from the implementation of an adapted annular denuder system (ADS) used to measure secondary PM2.5 from inside a broiler facility in Ontario, Canada. Results from this work show that secondary aerosols formed the majority of total PM2.5 during the early portion of the growth cycle. It was further determined that the ion balance between ammonium and anions was not consistent, leading to the conclusion that a significant portion of the aerosol species are associated with a previously unidentified source that is not necessarily due to secondary reactions. Keywords: Ammonia, Annular denuder system, Particulate matter, Poultry, Secondary aerosols.

Evaluation of chloride contributions from major point and nonpoint sources in a northern U.S. state

Chloride pollution of groundwater and surface water resources is an environmental concern in many regions. While use of road salt for winter road maintenance is known to be a major source of chloride in the environment, limited research has investigated the environmental impacts of chloride discharged from water softeners, particularly in areas with hard water. A chloride budget was developed for the state of Minnesota to estimate the amount of chloride discharged from household water softeners as well as other domestic, agricultural, commercial, and industrial sources. The analysis used multiple data sources, including salt sales records and wastewater monitoring data, and used statistical, spatial, and survey methods to estimate chloride loading from major sources statewide. Annual chloride mass contributions were estimated for the following sources: household water softener use; human excretions; household product use; chloride concentrations in drinking water; atmospheric deposition; road salt use; dust suppressant use; fertilizer application; industrial discharge; and livestock excretions. A mass balance for 96 wastewater treatment plants with effluent monitoring data showed that across these facilities, discharge from water softeners was the largest chloride source. A statewide chloride budget found that road salt was the largest source of chloride to the environment, but that WWTPs and fertilizer were also substantial sources, discharging 221,300 t and 209,900 t annually. Water softeners were estimated to contribute 65% of the chloride discharged to all 613 municipal WWTPs statewide. Methods used in this analysis could be applied to other communities, watersheds, or states with similar conditions. The results of the analyses indicate that water softening is an important chloride source in areas with hard water and underscore the importance of identifying and characterizing chloride sources in less urban areas, where deicing salt may be a less important contributor and receiving water bodies are often lakes, reservoirs, and streams.

Influence of potassium on the productivity and quality of potato: A Review

Potato ranks one of the most important food crops after rice, wheat, and other field crops. A healthy potato crop removes about 1.7 to 2.3 quintals of potassium ha-1, illustrating that the potassium requirement for potatoes is much higher than that of grains. Being a shallow root crop, the effectiveness of using potassium fertilizers on potatoes varies from 50 to 60 percent. Potassium nutrition plays an important role in increasing the potato yield, either due to the formation of large tubers or the increase in the number of tubers per plant. Among the integrated nutrient management in potatoes, farmyard manure improves the absorption and availability of potassium for potato plants. Potassium protects against frost and drought stress in plants and reduces the incidence of diseases or pests. Potassium availability also decreases the concentration of reducing sugar and improves the colour and quality of potato chips. Potassium sulfate improves potato quality better than sources of potassium chloride.

Isotope evidence for multiple sources of B and Cl in Middle Miocene (Badenian) evaporites, Carpathian Mountains

Evaporites of Middle Miocene Badenian stage occur widely in basins from the Carpathian Mountain region (Poland, Slovakia and Ukraine), but their source and formation process are still debatable. A detailed boron isotope study in combination with previous chlorine isotope and chemistry data of the salt samples from three localities (Wieliczka mine, Trans-Carpathian Basin, East Slovakian Basin) reveal ranges of δ11B (−4.5 to +35.7‰) and δ37Cl (−0.2 to +0.8‰). Modelling calculation indicates that both Rayleigh fractionation and incorporation of fluid inclusion solutes cannot cause such a large shift on δ11B values in halite. Instead, the B and Cl isotope data imply multiple brine sources, including evaporite brine, dissolved diapiric halite and basin brine in addition to the predominant seawater source during the formation of these evaporites. At Wieliczka salt mine, a positive δ11B excursion (from −5‰ to + 30‰) matches the negative δ37Cl variation (from +0.5 ± 0.1‰ to -0.2‰) stratigraphically upwards, which indicate both terrestrial boron and non-marine chloride made significant contributions to the composition of the basin brine during the early development of the basin. In the upper column, the δ11B values are within the marine range, but show influence by the sorption of boron onto clay, whereas the δ37Cl values at +0.5‰ still indicate the presence of non-marine chloride, possibly from recrystallized, diapiric halite. In the Trans-Carpathian Basin, constant δ37Cl (+0.3‰) and δ11B (+15‰) in the middle of the profile are consistent with a dominant marine source, whereas the lower δ11B (+2.2‰) and higher δ37Cl (+0.8‰) in the lower column suggest terrestrial fresh water flowed into the basin during the formation of basal halite. Halites in the upper part of the profile show near 0‰ of δ37Cl, suggesting incorporation of Cl from a mixture of expelled basin brines. In the Slovakian Basin, the δ11B values (+18.1 to +19.1‰) at the base of the profile lie within the marine range, but high δ37Cl values (+0.7 to +0.8‰) require a non-marine chloride source. In the upper part of the profile, boron isotope data indicate a change from marine (+12.2 to +23.4‰) to non-marine (+5.4 to +6.1‰) derivation of B, but the sources of Cl remain marine (+0.0 to +0.5‰). Overall, both B and Cl isotopes show coupled variation in the Middle Miocene Badenian evaporites and suggest multiple sources of B and Cl.

Solvent Extraction of Gold(III) with Diethyl Carbonate

Diethyl carbonate (DEC) was evaluated as a green, renewable alternative to methyl isobutyl ketone and dibutyl carbitol for the recovery of gold from copper-rich sources, such as anode slimes, by solvent extraction from chloride solutions. DEC is a powerful extractant at high chloride concentrations and can be used to sequester and concentrate gold from large volumes of dilute aqueous solutions containing high concentrations of copper. Stripping can be performed using pure water. Different variables were investigated: DEC concentration, chloride concentration, chloride source, phase volume ratio, and equilibration time. The selectivity and phase disengagement times were studied, and possible mechanisms of extraction are discussed and evaluated. In addition, the stability of DEC against hydrolysis was measured.

Chloride source delineation in an urban‐agricultural watershed: Deicing agents versus agricultural contributions

AbstractAnalyses (n = 525) of chloride (Cl−), bromide (Br−), nitrate as nitrogen (NO3‐N), sodium (Na+), calcium (Ca2+) and potassium (K+) in stream water, tile‐drain water and groundwater were conducted in an urban‐agricultural watershed (10% urban/impervious, 87% agriculture) to explore potential differences in the signature of Cl− originating from an urban source as compared with an agricultural source. Only during winter recharge events did measured Cl− concentrations exceed the 230 mg/L chronic threshold. At base flow, nearly all surface water and tile water samples had Cl− concentrations above the calculated background threshold of 18 mg/L. Mann–Whitney U tests revealed ratios of Cl− to Br− (p = .045), to NO3‐N (p < .0001), to Ca2+ (p < .0001), and to Na+ (p < .0001) to be significantly different between urban and agricultural waters. While Cl− ratios indicate that road salt was the dominant source of Cl− in the watershed, potassium chloride fertilizer contributed as an important secondary source. Deicing in watersheds where urban land use is minimal had a profound impact on Cl− dynamics; however, agricultural practices contributed Cl− year‐round, elevating stream base flow Cl− concentrations above the background level.

It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH.

Aqueous ring-opening metathesis polymerization (ROMP) is a powerful tool for polymer synthesis under environmentally friendly conditions, functionalization of biomacromolecules, and preparation of polymeric nanoparticles via ROMP-induced self-assembly (ROMPISA). Although new water-soluble Ru-based metathesis catalysts have been developed and evaluated for their efficiency in mediating cross metathesis (CM) and ring-closing metathesis (RCM) reactions, little is known with regards to their catalytic activity and stability during aqueous ROMP. Here, we investigate the influence of solution pH, the presence of salt additives, and catalyst loading on ROMP monomer conversion and catalyst lifetime. We find that ROMP in aqueous media is particularly sensitive to chloride ion concentration and propose that this sensitivity originates from chloride ligand displacement by hydroxide or H2O at the Ru center, which reversibly generates an unstable and metathesis inactive complex. The formation of this Ru-(OH)n complex not only reduces monomer conversion and catalyst lifetime but also influences polymer microstructure. However, we find that the addition of chloride salts dramatically improves ROMP conversion and control. By carrying out aqueous ROMP in the presence of various chloride sources such as NaCl, KCl, or tetrabutylammonium chloride, we show that diblock copolymers can be readily synthesized via ROMPISA in solutions with high concentrations of neutral H2O (i.e., 90 v/v%) and relatively low concentrations of catalyst (i.e., 1 mol %). The capability to conduct aqueous ROMP at neutral pH is anticipated to enable new research avenues, particularly for applications in biological media, where the unique characteristics of ROMP provide distinct advantages over other polymerization strategies.

The aza‐Prins Cyclization of Unfunctionalized Olefins Promoted by NHC‐Cu Complex and ZrCl4

The aza‐Prins cyclization reaction catalyzed by ZrCl4 and NHC (N‐heterocyclic carbene) metal complexes is firstly reported. NHC‐copper complexes as promoter and ZrCl4 as chloride source are utilized under a mild condition, where homoallylic amines and aldehydes are successfully converted to piperidine derivatives in satisfactory yields and diastereoselectivity.

The Effect of Micro-Steel Fiber on the Corrosion Steel Reinforcement

There are many possible sources of ion chloride which can be open to concrete during service. Structure thesaurus to the sea may be sprayed with salt mist or seawater carried by the wind. In order to understand the behaviour of structures, different levels of corrosion must be studied. The current study has been taken up to investigate the behaviour of Reinforcement Concrete beams (RC) and bond strength of specimens exposed to 5% chloride solution, to cause corrosion of reinforcement. Two types of mixing by using Ordinary Portland Cement (OPC) type (I) concrete (with and without using micro steel fiber Vf =1.2) to cast eight reinforce concrete supported simply beam. Corrosion was accelerated using electrical current with different density to cause mass loss in steel bar with different levels of 6 %, 10 %, and 16 %. The results of the bond test and beams show a decrease in capacity with increasing the corrosion. The micro steel fiber causes an increase in bond strength of concrete ranged from (40-60%), and an increase in ultimate strength of beams ranged from (4 to 38 %) as compared with the beam without steel fiber.

Use of Seawater/Brine and Caliche’s Salts as Clean and Environmentally Friendly Sources of Chloride and Nitrate Ions for Chalcopyrite Concentrate Leaching

A less harmful approach for the environment regarding chalcopyrite concentrate leaching, using seawater/brine and caliche’s salts as a source of chloride and nitrate ions, was investigated. Different variables were evaluated: sulfuric acid concentration, sodium nitrate concentration, chloride concentration, source of water (distilled water, seawater, and brine), temperature, concentrate sample type, nitrate source (analytical grade and industrial salt), and pre-treatment methods in order to obtain maximum copper extraction. All tests were performed at moderate temperatures (≤45 °C) and atmospheric pressure. The leaching system using distilled water, seawater, and brine base media resulted in copper extraction of 70.9%, 90.6%, and 86.6% respectively. The leaching media, with a concentration of 20 g/L Cl−, obtained a maximum Cu extraction of 93.5%. An increase in the concentration of H2SO4 and NaNO3 from 0.5 to 0.7 M, led to an increase in the copper extraction. The use of an industrial salt compared to the analytical salt did not show great variations in the percentage of extraction achieved, which would be a good and cost effective alternative. The increase in temperature from 25 to 45 °C showed a great effect on the copper leaching (of 60% until 90.6%, respectively). The pre-treatment is suggested to increase copper extraction from 60.0% to 71.4%.

Observation of Road Salt Aerosol Driving Inland Wintertime Atmospheric Chlorine Chemistry.

Inland sources of particulate chloride for atmospheric nitryl chloride (ClNO2) formation remain unknown and unquantified, hindering air quality assessments. Globally each winter, tens of millions of tons of road salt are spread on roadways for deicing. Here, we identify road salt aerosol as the primary chloride aerosol source, accounting for 80–100% of ClNO2 formation, at an inland urban area in the wintertime. This study provides experimental evidence of the connection between road salt and air quality through the production of this important reservoir for nitrogen oxides and chlorine radicals, which significantly impact atmospheric composition and pollutant fates. A numerical model was employed to quantify the contributions of chloride sources to ClNO2 production. The traditional method for simulating ClNO2 considers chloride to be homogeneously distributed across the atmospheric particle population; yet, we show that only a fraction of the particulate surface area contains chloride. Our new single-particle parametrization considers this heterogeneity, dramatically lowering overestimations of ClNO2 levels that have been routinely reported using the prevailing methods. The identification of road salt as a ClNO2 source links this common deicing practice to atmospheric composition and air quality in the urban wintertime environment.

Leaching of Pure Chalcocite in a Chloride Media Using Waste Water at High Temperature

Studying the dissolution of chalcocite allows to understand the behavior of the most abundant secondary sulfide ore in copper deposits, while digenite (Cu1.8S) and other intermediate sulfides (Cu2−xS) are often associated with chalcocite. The most common mechanism of dissolution is by two stages, and chloride ions benefit the kinetics of dissolution. In this study, a pure chalcocite mineral (99.9% according to XRD (X-Ray Diffraction) analysis) is leached in chloride media using NaCl and wastewater as the sources of chloride. Magnetic leaching tests are performed at 65, 75, and 95 °C, using a particle size between −150 and + 106 μm. Chloride concentration and leaching time are the main variables. A substantial dissolution of chalcocite was obtained with 0.5 M H2SO4, 100 g/L of chloride and a leaching time of 3 h. The apparent activation energy (Ea) derived from the slopes of the Arrhenius plots was 36 kJ/mol. The XRD analysis proves the presence of elemental sulfur (S0) as the main component in the leaching residue. No significant differences in copper extraction were detected when using 100 g/L of chloride ion or wastewater (39 g/L).

Residual effect of KCl coated by polymeters incorporated in a corn crop

The use of polymer-coated potassium fertilizers may reduce the leaching of potassium (K) in the soil, increasing the availability of this nutrient to plants for a long period. In this context, the residual effect of doses and sources of potassium chloride (KCl) application on K nutrition, production components and corn grain yield in two sequential crops were investigated in this study. The experiment was conducted in a clayey Oxisol. The experiment was arranged in a randomized complete block design with four replicates in a 4 X 4 factorial scheme: four potassium doses (0, 40, 80 and 120 kg ha-1 of K2O ) and four KCl sources [uncoated fertilizer (conventional) and three sources of fertilizer coated with different polymers]. The KCl sources showed the same residual effect for most production components, leaf K content and corn grain yield in both crops. The increase of K fertilizer doses in the previous crop provided residual effect on the second-harvest corn crop, resulting in linear increase in leaf K content, weight of 100 grains and grain yield up to the dose of 77 kg ha-1, whit the use of any source of KCl.

Stress Corrosion Cracking of High-Pressure Scrubber in Urea Plant: A Case Study

This current work investigates the failure of high pressure (HP) scrubber lining in urea fertilizer production plant after 20 years in service. AISI 316L urea grade (UG) stainless steel scrubber lining was showed severe damage. In order to find out the root cause of failure, cracks were observed by visual inspection together with microstructure examination Chemical analysis of the base metal and corrosion products were analyzed Chemical analysis of the lining base alloy is conformed to the AISI 316L UG. Results revealed existence of chloride assisted stress corrosion cracking (SCC) initiated from pitting formed in the inner surface of the scrubber lining. Corrosion products analysis revealed existence of chloride (Cl-). Localized pitting corrosion is attributed to Cl attack. The expected sources of chloride are water during hydrostatic testing, water vapor during passivation, chloride containing atmosphere during transportation or storage the base alloy in coastal areas and water vapor in carbamate gasses (process fluid). Pits initiated at the lining inner surface act as stress concentration sites assisted SCC initiation. Chloride SCC is caused by simultaneous action of both tensile stresses and a corrosive environment containing chloride. To overcome the scrubber failure, chloride must be eliminated and residual stresses must be controlled. Upgrading the scrubber base alloy using high-alloy duplex stainless steel (Safurex) is highly recommended.

Modifying SWAT-CS for simulating chloride dynamics in a Boreal Shield headwater catchment in south-central Ontario, Canada

Rising chloride concentrations in surface water due to applications of deicing practices is proving detrimental to aquatic systems. In this study, a new chloride module is developed for a version of the Soil and Water Assessment Tool specially designed for Canadian Shield catchments (SWAT-CS) to model long-term chloride dynamics in a headwater catchment in south-central Ontario, Canada. In this modified model (SWAT-CS-CL; extended SWAT-CS model for chloride), chloride sources, sinks, internal storages or pools, and movement between these components are depicted. Performance of SWAT-CS-CL is assessed using a two-stage evaluation process based on the generalized likelihood uncertainty analysis (GLUE) framework. SWAT-CS-CL was found to perform moderately well, with simulated monthly chloride in streams and lake outflow following overall chloride trends and capturing regular chloride dynamics. However, simulations fail to consistently reproduce some instances of large or low chloride fluxes. Limitations in simulating large chloride fluxes may be attributed to the inadequate ability for SWAT-CS-CL to closely simulate snowpack and snowmelt processes. Parameter transferability among sub-catchments does suggest that there is a potential to extend SWAT-CS-CL to other Canadian Shield catchments for chloride modelling. Further improvements are needed through more trials to other catchments in a same or different landscape, and by modifying the simulation structure, especially representation of snow hydrology and chloride inputs.

Palladium/aluminium-cocatalyzed carbonylative synthesis of 2-chloroethyl benzoates from epoxides and aryl iodides

A new straightforward and efficient procedure for the palladium/aluminium-cocatalyzed carbonylative synthesis of 2-chloroethyl benzoates from epoxides and aryl iodides has been developed. By using TFBen (benzene-1,3,5-triyl triformate) as the CO source and LiCl as the chloride source, AlCl3-catalyzed regioselective ring-opening of epoxides was merged successfully with the palladium-catalyzed carbonylative cross-coupling of aryl iodides. A variety of the desired 2-chloroethyl benzoates were obtained in moderate to excellent yields with very good substrates compatibility.

Chloride Balance in Freshwater System of a Highly Anthropized Subalpine Area: Load and Source Quantification Through a Watershed Approach

AbstractRecent studies have highlighted an increase of chloride in many lakes worldwide, with negative effects on chemical and physical properties of inland waters and freshwater biota. In this study, we assessed the long‐term trend (1993–2017) of chloride in Lake Iseo, located in the midlatitudes, and analyzed its relationship with discharge data of the inflows and hydrological and hydroclimatic changes. Additionally, we performed a specific annual survey, collecting water samples at a biweekly frequency in tributaries, calculating chloride load, and comparing the result with the chloride increase observed in lacustrine water. The combined use of Geographic Information System (GIS) and multivariate analyses allowed identification of possible sources of chloride and their seasonal dynamic within the mixed‐land‐use watershed: impervious surface and deicing salt, population and sewage effluents, livestock, and rainwater. Their potential contribution to total mass balance was assessed, cross‐checking the results between chloride source evaluation and load estimation. Chloride load from wastewater treatment plants played an important role, albeit we highlighted that the main source was the road deicing salt, with a primarily winter contribution. The increased anthropization in the watershed was likely the main cause of the chloride enhancement. This study demonstrates that the problem of salinization can also affect lakes located in the midlatitude areas and provides a reproducible method for the identification and quantification of the different sources. Our results will help to better understand the potential sources of salinity in rivers that may reveal processes controlling the salinization of freshwater systems, with implications for future management practices.