Chlorine Components Research Articles

A new absorbent system for reducing chlorine gas escape and enhancing pollutants removal during ship exhaust wet scrubbing

Using chlorine-containing oxidants to remove pollutants in the exhaust gas of ships is normally accompanied by Cl2 escape, which poses a significant threat to the environment and the health of the crew. This paper proposes a method to solve the problem of Cl2 escape in a single NaClO solution system using BAD (a new amide absorbent, C12H25NO). The electrostatic potential (ESP) theoretical calculations, FT-IR and UV–vis spectra tests showed that the strong field effect interaction between BAD and Cl2, which can form a stable symmetrical structure similar to a “sandwich”, results in a strong binding ability of BAD to Cl2. The effects of the initial pH, the concentration of NaClO solution, aeration time, and some operating parameters on the loss of active chlorine (AC) components were studied. Under the same conditions, a two-phase composite absorbent system with the addition of BAD can reduce the loss of AC components by 32.67% on average and up to 56.12%. It also can effectively capture the Cl2 escaping with the gas flow and keep it in the system, which enhances the oxidation of NO by Cl2 at the gas–liquid interface. It also has a strong ability to remove pollutants for a long period, as the removal efficiencies of SO2, NO, and NOx within 20 mins were 97.84%, 77.98%, and 76.01%, respectively. The results show that the BAD-NaClO two-phase composite absorbent system can effectively reduce Cl2 escape, and it is a sustainable wet treatment scheme for ship exhaust gas with great application prospects.

Controlling Role of CaClOH in the Process of Dechlorination for Municipal Solid Incineration Fly Ash Utilization

The existence of high chlorine components in municipal solid waste incineration fly ash (IFA) has become a key bottleneck in the utilization of IFA as building materials. In this work, the chlorides in IFA were classified as alkali chlorine, calcium chloride, and calcium aluminum chloride, whereas CaClOH was the dominant phase of calcium chloride. For the first time, the effects of CaClOH on chlorine elimination for IFA-derived products by water-washing treatment or high-temperature treatment were carefully examined. The results indicated that IFA chlorine removal was closely linked to CaClOH phase dissolution, decomposition, volatilization, and transformation. CaClOH was easily removed by water washing and had excellent thermostability, even at 1300 °C. As shown in the results of XRD and XRF, the siliceous component would combine with CaClOH to volatilize as SiCl4, whereas the aluminous component would react with CaClOH to form chlorine-fixed and stable calcium aluminum chloride phases. The calcium aluminum chloride instead of CaClOH was in favor of the transformation of residual chlorine from soluble chlorine to chemically fixed chlorine. Therefore, the detoxification mechanism of chlorine for IFA could be summarized as washing dechlorination, volatilization dechlorination, and chemical fixation. As an application, the synergistic treatment of IFA with siliceous/aluminous materials could greatly reduce risks from soluble chlorine, while IFA-derived products were used as building materials.

Waste into Fuel—Catalyst and Process Development for MSW Valorisation

The present review paper highlights recent progress in the processing of potential municipal solid waste (MSW) derived fuels. These wastes come from the sieved fraction (∅ < 40 mm), which, after sorting, can differ in biodegradable fraction content ranging from 5–60%. The fuels obtained from these wastes possess volumetric energy densities in the range of 15.6–26.8 MJL−1 and are composed mainly of methanol, ethanol, butanol, and carboxylic acids. Although these waste streams are a cheap and abundant source (and decrease the fraction going to landfills), syngas produced from MSW contains various impurities such as organic compounds, nitrogen oxides, sulfur, and chlorine components. These limit its use for advanced electricity generation especially for heat and power generation units based on high temperature fuel cells such as solid oxide fuel cells (SOFC) or molten carbonate fuel cells (MCFC). In this paper, we review recent research developments in the continuous MSW processing for syngas production specifically concentrating on dry reforming and the catalytic sorbent effects on effluent and process efficiency. A particular emphasis is placed on waste derived biofuels, which are currently a primary candidate for a sustainable biofuel of tomorrow, catalysts/catalytic sorbents with decreased amounts of noble metals, their long term activity, and poison resistance, and novel nano-sorbent materials. In this review, future prospects for waste to fuels or chemicals and the needed research to further process technologies are discussed.

Greenhouse gases and future long‐term changes in the stratospheric temperature and the ozone layer

A numerical two‐dimensional (2D) interactive dynamical–radiative–photochemical model including aerosol physics is used to examine the expected long‐term changes in stratospheric temperature and the Earth's ozone layer due to anthropogenic pollution of the atmosphere by the greenhouse gases CO2, CH4 and N2O. The model time‐dependent runs were made for the period from 1975 to 2050. The results of the calculations show that the basic mechanism by which greenhouse gases influence the ozone layer is stratospheric cooling accompanied by a weakness in the efficiency of the catalytic cycles of ozone destruction due to temperature dependencies of the photochemical gas‐phase reactions. Modification of polar stratospheric clouds (PSCs) caused by anthropogenic growth of the greenhouse gases is important only for the polar ozone. An essential influence of the greenhouse gases on the ozone by a modification of the stratospheric sulphate aerosol is revealed. The aerosol changes caused by the greenhouse gases modify the distribution of the ozone‐active gaseous chlorine, bromine and nitrogen components by means of heterogeneous reactions on the aerosol surface, resulting in a significant decrease in springtime polar ozone depletion of the Antarctic ozone hole.

The influence of products and by-products obtained by drinking water electrolysis on microorganisms

It is the aim of this work to underline the chemical character of disinfection processes and to present the results of treatment experiments for artificially and electrochemically added chemicals focusing on chlorine components and hydrogen peroxide obtained on IrO 2/RuO 2 anodes. A discontinuous cell with rotating anode placed 4 mm above an IrO 2 expanded mesh cathode of same diameter was used for the generation of electrolysis products. The thermostated experiments were carried out at a temperature of 20 °C and in constant current mode. Artificial solutions prepared using sodium salts and deionised water were electrolysed. Samples were analysed using the DPD ( N, N-diethyl- p-phenylendiamine) method. Escherichia coli K-12, Bacillus subtilis DSM 2277 and Saccharomyces cerevisiae Kolin were used as test-microorganisms. Morphological changes were studied using transmission electron microscopy. The results show that electrolysed water had a higher lethal efficiency than Ca(OCl) 2 of the same measured active chlorine concentration. During the killing period mainly inner cell parts of the microorganisms react chemically with the disinfectants. In sufficiently high concentrations and reaction times, the cell material continues to react. Cell walls or membranes can break-through as electron microscopy pictures show. Electrolysed water had a higher lethal efficiency on microorganisms. This behaviour demonstrates the existence of additional by-products.

Eu-doped Ca 8Mg(SiO 4) 4Cl 2 phosphor particles prepared by spray pyrolysis from the colloidal spray solution containing ammonium chloride

The green-emitting Ca 8Mg(SiO 4) 4Cl 2:Eu 2+ phosphor particles were prepared by spray pyrolysis from the colloidal spray solution that contained fumed silica and ammonium chloride. The ammonium chloride was used as the source of chlorine and the flux material. The ratios of the calcium and chlorine components that were dissolved into the spray solution were changed from 1:0.25 to 1:2.5. The phosphor particles prepared from the spray solution with the proper amount of ammonium chloride added to the spray solution had fine sizes and regular morphologies. The phase-pure Ca 8Mg(SiO 4) 4Cl 2:Eu 2+ phosphor particles were obtained from the spray solution that had a ratio of calcium to chlorine components in the range of 1:0.5 to 1:1.5. The post-treated phosphor particles had a broad excitation wavelength that ranged from 260 to 480 nm, irrespective of the amount of ammonium chloride added to the spray solution. The phosphor particles prepared from the spray solution with a 1:1 ratio of calcium to chlorine had maximum emission intensity under a long-wavelength ultraviolet.

Blue-Emitting Eu-Doped (Sr, Mg)5(PO4)3Cl Phosphor Particles Prepared by Spray Pyrolysis from the Spray Solution Containing Ammonium Chloride

Blue-emitting strontium magnesium halophosphate phosphor particles were prepared by spray pyrolysis from the spray solutions with ammonium chloride. The ammonium chloride was used as the source of chlorine and the flux material. The prepared (Sr, Mg)5(PO4)3Cl : Eu2+ phosphor particles had regular morphologies and fine sizes. The mean sizes of the (Sr, Mg)5(PO4)3Cl : Eu2+ phosphor particles were each 1.2 and 1.9 μm when the ratios of strontium to chlorine components were 1 : 0.5 and 1 : 1. The ratios of strontium to chlorine components in the as-prepared and post-treated particles were each 1 : 0.26 and 1 : 0.21. The (Sr, Mg)5(PO4)3Cl : Eu2+ phosphor particles that were prepared from the spray solution with the ratio of strontium to chlorine components of 1 : 1.5 had the maximum photoluminescence intensity, which was 176% of that of the commercial BaMgAl10O17 : Eu2+ phosphor particles under excitation wavelength of 400 nm.

Recovery of chlorine gas from waste polyvinyl chloride for better environment.

New recycling process of chlorine component in polyvinyl chloride was proposed. Hydrogen chloride, evolved from polyvinyl chloride by heating at 533K, was conducted into metal oxides at 573K to form the corresponding metal chloride. The metal chlorides were then regenerated to metal oxides and chlorine gas by introducing oxygen gas at 673K. Among the metal oxides studied, cobalt oxide was the most effective both for the fixation and release of chlorine components. More than 60% of chlorine ions in PVC was recovered as chlorine gas even after 50 times of the iterative uses.

The TDLAS instrument for the detection of total inorganic chlorine in the stratosphere

A novel method based on tunable diode laser absorption spectroscopy is proposed for the detection of the sum of the stratospheric chlorine components HCl, ClONO2, ClOOCl and ClO. All of the above species are detected as HCl following thermal decomposition (ClONO2 and ClOOCl) to ClO which is converted to Cl via reaction with NO; the Cl atom is then rapidly reacted with a hydrocarbon to form HCl. The method has been investigated in the laboratory for detection of ClONO2, for which the conversion efficiency was found to be 100% under suitable conditions.

Structure and stability of chlorosiloxanes

SINDO1 calculations were performed to determine the structure and stability of chlorosiloxanes of the groups Si n O n−1 Cl 2 n+2 , Si n O n Cl 2 n and Si n O n+ m Cl 2 n−2 m . A comparison of isomers and sequences reveals the preferred stabilization with increasing size. The most stable structures can be characterized as chains and monocyclic and oligocyclic rings. Model reactions were undertaken to understand the growth pattern of increasing oxygen and decreasing chlorine components.

Component Patterns of Chlordanes in Human Milk, Cow's Milk, Dog Adipose Tissue, Cat Adipose Tissue and Wild Bird

The component patterns of chlordanes (total of 19 compounds) in human milk (n=12), cow's milk (n=10), dog adipose tissue (n=4), cat adipose tissue (n=6) and wild bird (2 species) were examined by mass spectrometry with selected ion monitoring. The component patterns in these samples were extremely different from those of aquatic biota described previously. In these higher animal samples, relatively high levels of residues of higher chlorine components (e. g. trans-, cis-nonachlor) and metabolites (oxychlordane, heptachlor epoxide) in relation to chlordanes were observed, though the component patterns varied in the different species of animal. High levels of residues of higher chlorine components were found in human milk, cat adipose tissue and wild bird samples, while the levels of metabolite residues were high in cow's milk and dog adipose tissue samples. The differences of component patterns may be due to species differences of metabolic activity.

Chemical Analysis of Aerosol Particles and of Gas Traces on the Island of Hawaii

Aerosols of two different size ranges with radii between 0.08 < r < 0.8 μ (large particles) and 0.8 < r < 8 μ (giant particles) were analyzed for NH4+, Cl−, SO4− and NO3− Parallel with this, the concentration of corresponding gas traces, that is of NH3, chlorine components, SO2 and nitrogen dioxide was measured.
 The results show that the giant particles consisted almost entirely of sea spray. Their content of NO3− was small compared to the data from the East Coast of the United States (Round Hill, Massachusetts and Homestead, Florida).
 The Cl− content of the large particles was less than 1.5 % of that of the giant particles, confirming previous data which showed that the sea spray is almost completely restricted to particles larger than 0.8 μ radius. The large particles contained NH4 in amounts comparable with the other components, indicating the presence of other than sea spray nuclei in this size range. The NH4 is probably present in the form of (NH4)2SO4.
 Both particle sizes were completely missing in the raining orographic clouds.
 All gas components were found to be present and the concentrations did not fluctuate very much. They were washed out, to a small degree, if at all, by rain.

Recent Investigations in Air Chemistry

New results of chemical analyses of natural aerosol particles in Florida and in the Boston area are presented. These data are compared with the results obtained earlier at various other locations. The continental and maritime components of NH4, Na2, Cl, SO4, and NO3 can be separated for two different size ranges, viz. large particles (radius 0.08 μ to 0.8 μ) and giant particles (radius 0.8 μ to 8 μ). It is found that the continental influence on aerosols extends far into the ocean. The nitrate content of the particles presents an especially interesting problem, since it appears that the major part of NO3 stems neither from a continental nor from a maritime source, but from a certain area along the coast. A comparison is made of the total amounts of material found in the large and the giant particles of the various locations. Information gained from this comparison provides the basis for conclusions regarding the size distribution of aerosols. A pronounced difference between maritime and continental distributions becomes evident in this case. The concentration of the corresponding gas traces of NH3, SO2, nitrogen oxides and chlorine components were measured in Florida and at other locations simultaneously with the chemical analysis of the aerosols. For most components the concentration of these gas traces is considerably higher than that for the corresponding substances in the aerosols. The importance of these findings for air chemistry is discussed.