Release Of Chlorine Research Articles

Boosting seawater denitrification in an electrochemical flow cell

Nitrogen compounds in current seawater treatment processes typically are converted to nitrate, threatening seawater quality and marine ecology. Electrochemical denitrification is a promising technique, but its efficiency is severely limited by the presence of excess chloride ions. In this work, a flow-through cell went through an on-demand chlorine-mediated electrochemical-chemical tandem reaction process was designed for efficient seawater denitrification. Equipped with ultrathin cobalt-based nanosheets as the cathode catalyst and commercial IrO2-RuO2/Ti as the anode, the newly designed flow-through cell achieved nitrate removal efficiency that was about 50 times greater than the batch cell and nearly 100 % N2 selectivity. Moreover, nitrite and ammonia can also be removed with over 93 % efficiency in total nitrogen (TN) removal. Furthermore, the concentration of active chlorine in the effluent could be adjusted within two orders of magnitude, enabling on-demand release of active chlorine. Finally, this flow-through cell reduced the TN of actual mariculture tailwater (40.1 mg N L-1 nitrate) to only 5.7 mg N L-1, meeting the discharge standard for aquaculture tailwater of Fujian, China. This work demonstrates the paradigm of deep denitrification from ultra-concentrated chlorine ion wastewater using an on-demand active chlorine-mediated electrochemical-chemical tandem reaction process.

Long-lasting renewable antibacterial N-halamine coating enable dental unit waterlines to prevention and control of contamination of dental treatment water

Developing bacterial biofilm on the dental unit waterlines increases the risk of cross-infection among oral patients. Although chemical disinfectants can achieve disinfection effects in a short period of time, corrosion damage of dental unit waterlines and water contamination can also occur after continuous use of it. Herein, this study explored a one-step deposition method to prepare a durable and renewable antibacterial N-halamine polymeric coating on polyurethane waterlines. The method utilized polyelectrolyte complexes formed with polyethylenimine (PEI) and phytic acid (PA), followed by chlorination to activate the antibacterial properties. The N-halamine polymeric coating reduces the polyurethane waterline’s water contact angle, thus reducing biofouling deposits and the obstruction of the active halide site on the waterlines, thereby facilitating the maintenance of the cleanliness of the coating. In addition, benefiting both from the active chlorine release and the high density of positive charges on the coating, the polyurethane waterline antimicrobial activity is significantly enhanced. Besides, the N-halamine polymeric coating is biocompatible. This study showed that long-lasting and renewable antimicrobial requirements can be achieved by simple surface modification of N-halamine polymer coatings, which provides a practicable strategy for the production of long-term and reproducible antibacterial dental unit waterlines to reduce the incidence of hospital infection in oral department.

Study of chlorine removal from shredder residue: Thermal dechlorination and water leaching

Shredder residue (SR) is an inevitable waste in the production of steel by scrap melting, and the presence of chlorine is the main responsible for its non-use of energy. This study aimed to remove chlorine from SR by thermal dechlorination and water leaching. Thermal dechlorination was first studied from a PVC sample to evaluate the optimum parameters of temperature, heating rate, residence time and atmosphere (N2 or steam). Under optimal conditions for PVC dechlorination, chlorine removals of 73.7 (N2) and 68.0% (steam) were achieved. Optimal parameters were applied to thermal dechlorination of a Brazilian SR with a chlorine content of 2.12 wt%. Reductions in chlorine content to 0.95 and 0.51 wt% were observed with N2 and steam atmospheres, respectively. In an additional evaluation (conducted also with the Brazilian SR and in order to investigate the reactor rotation effect), it was observed that the reactor rotation does not influence the release of chlorine during the thermal treatment but modifies the granulometry of the produced solid. Samples obtained from this test were subjected to a water leaching study to further reduce the chlorine content. The parameters studied were the type of water (tap and distilled), granulometry and carbonation (contact with CO2) in a total of five washing cycles. Carbonation and use of distilled water achieved the highest chlorine removal resulting in a reduction of chlorine content from 1.13 to 0.45 wt%. The obtained results show directions for chlorine removal aiming at the energetic use of shredder residue.

Pyrolysis of municipal plastic waste: Chlorine distribution and formation of organic chlorinated compounds

The release of chlorine during the pyrolysis of actual municipal plastic waste (MPW) was studied. Firstly, thermogravimetry-Fourier transform infrared (TG-FTIR) was analyzed to investigate the chlorine release behavior. Then, the effect of temperature on chlorine migrations was investigated by fast pyrolysis experiments in a fixed bed reactor. Results showed that chlorine released mainly between 241 and 353 °C in the form of HCl or chloroesters during MPW pyrolysis. After pyrolysis, chlorine was mainly distributed in the pyrolytic gas (74.34–82.89 %) and char (10.17–21.29 %). However, the release of chlorine was inhibited due to the melting behavior of MPW at <350 °C. Besides, the relative contents and types of organic chlorinated compounds in liquid products were both decreased with temperature. It was observed that polyethylene terephthalate (PET) was the greatest contributor to the formation of organic chlorinated compounds during MPW pyrolysis. Meanwhile, the pyrolysis of PET was significantly promoted by the HCl released from polyvinyl chloride (PVC). Subsequently, the pathways for the formation of organic chlorinated compounds through the co-pyrolysis of PVC and PET were proposed, including the initial degradation and subsequent chlorination of PET. These findings provided new insights into the release and regulation of chlorine-containing pollutants during actual MPW pyrolysis.

Accidental release of chlorine from a cylinder during transport and an emergency response plan: A scenario-based study.

This article summarizes our research study on the scenario of an accidental chlorine gas release during transportation and preparing emergency response plan to mitigate the subsequent hazards in urban areas. To conduct the research study, the event tree analysis (ETA), a series of brain storming sessions, and a modeling of consequences of an accident using the Phylogenetic Analysis with Space/Time models (PHAST) software were employed. Based on the result of the event tree, 32 initial occurring paths and 20 eventual occurring paths are identified as the outcome. The evacuation time is about 41 seconds, which is very short, and the odds of casualties are estimated at 99 percent within a radius of 140-192 m from the release site, 50 percent within a radius of 202-599 m, and 1 percent within a radius of 758 m. Along with the use of consequence modeling, the development of the ETA can be effective in emergency preparedness. In the case of a chlorine gas release, it would not be possible to effectively control the source of release. Furthermore, the result indicates that in a major city like Tehran, the application and transport of chlorine gas can be a serious challenge.

Hybrid PANI-halamine design, synthesis and antibacterial activity

This study describes the design, preparation and testing of a series of novel hybrid antibacterial polymers based on polyaniline (PANI) and halamine. A melamine-aniline monomer was synthesized and utilized as end groups in the polymerization of aniline, under ultrasonic field, followed by chlorination under mild acidic conditions, to afford the desired hybrid materials. PANI-halamine hybrids were characterized by FTIR-ATR, SEM and EDAX. The combined biostatic and biocidal activity of PANI and active chlorine was investigated against gram-positive and gram-negative bacterial strains. In contrast to parent PANI, the hybrids were found to exhibit diffused antibacterial activity, resulting in inhibited bacterial growth zones. It was found that, apart from the obvious active species in the polymers, added surfactants like DBSA, had strong influence on release of active chlorine from the hybrid halamine moieties, thus diminishing the antibacterial efficacy of the final hybrids.

Oxidation of sulfide mineral and metal extraction analysis in the microwave-assisted roasting pretreatment of refractory gold ore

The recovery of gold from refractory ore could guarantee sustainable development in the gold industry. However, there are many challenges in the treatment of ore, such as environmental pollution and low recovery. In this regard, the current research focuses on the pretreatment of refractory gold ore and investigates the effect of microwave power, the role of additives, and water on the oxidation and decomposition of sulfide minerals. Pretreatment using microwave-assisted roasting with NaClO3 as an additive to the oxidizing agent is a new method of processing refractory gold ore. Oxidation was studied through sulfur and chlorine mass balance analysis and the degree of metal extraction from sulfide minerals. SEM analysis was carried out to complete the study of the phase change of compounds in the oxidation of mineral sulfides. Roasting of refractory gold ore with a composition of 180 kg NaClO3 and 180 kg water/ton ore reached a temperature of 470 °C at a microwave power of 400 watts for 30 minutes. Total oxidized sulfur reached 90.6%, while only 10.4 % of the sulfur was released, and chlorine release was 49.5%. In addition, water leaching was conducted to investigate the extraction rate of metals after roasting. The results showed that the water leaching extraction of Cu, Zn, Pb, and Fe reached 84.3%, 97.6%, 22.8%, and 8.4%, respectively. Applying microwaves with appropriate concentrations of additives and water resulted in high oxidation of sulfide minerals (>90%) and low sulfur emissions in roasting refractory gold ore with relatively low power, temperature, and time. Moreover, leaching this roasted gold ore resulted in gold extraction of 92.5%; however, leaching of refractory gold without pretreatment resulted in gold extraction of only 47.5%.

Migration characteristics of chlorine during pyrolysis of municipal solid waste pellets

The migration process of chlorine during municipal solid waste (MSW) pellets pyrolysis was studied in a fixed bed reactor. Distribution and speciation changes of chlorine at different pyrolysis temperatures were determined by ion chromatography (IC) and X-ray photoelectron spectroscopy (XPS) analyses. Results showed that chlorine was mainly distributed in pyrolysis char (42.36–65.29 %) and gas (26.66–35.03 %) after MSW pellets pyrolysis. With the temperature increasing, chlorine in char and tar was enriched due to the increase of chlorine release and the decrease of product yields, with chlorine concentration increasing to 3498 ppm and 1415 ppm at 800 °C, respectively. Results of chlorine forms analysis indicated that most of the organic-Cl in MSW was released into the volatiles during pyrolysis due to the dissociation of CCl. Inorganic-Cl became the dominant form of chlorine in char after pyrolysis, with the proportion increasing from 46.69 % (raw) to 61.22 % (500 °C), which also suggested that part of organic-Cl was converted into the inorganic-Cl. Notably, the proportions of inorganic-Cl decreased at >600 °C due to the migration of inorganic. In addition, the pyrolysis release behavior of chlorine was affected by the pore structure of char, which could be inhibited by the unprosperous pores in char, especially at low temperatures (<600 °C). These findings provided a reference for the chlorine regulation of MSW pyrolytic products.

Temperature resolved release of inorganic compounds from biomass

The release of inorganic compounds during the thermal conversion of solid biomass can cause severe operational problems in thermal power plants. To effectively reduce fine particle emissions and depositions, it is important to understand the release of problematic elements into the gas phase.This study presents a temperature-resolved analysis of the release of potassium, sodium, chlorine, sulfur, phosphorus, calcium, and magnesium from ten biomass samples. Conventional woody biofuels, alternative woody biofuels, and stalk-like biomass are analyzed in an electrothermal vaporization unit (ETV) which is connected directly to an inductively coupled plasma optical emission spectrometer (ICP-OES). The suppression of secondary gas-phase reactions in the given setup enables the isolated observation of each individual species’ release pattern. The results from this experimental setup are compared to a range of release patterns found in the literature, with a particular focus on potassium. For the high heating rates applied in this setup, the potassium release starts at around 700 °C, with the majority being release between 1000 °C and 1400 °C. Since hardly any potassium is released together with chlorine and sulfur, the majority of it is released as KOH or elemental potassium. Overall, this work presents reproducible temperature-resolved release patterns of inorganic elements from various biogenic feedstocks in an inert atmosphere.

High-strength hydrophilic N-halamines chitosan and cellulose nanofibers membranes with repeated bactericidal properties

Direct addition of disinfectants and membrane separation techniques have been common methods to address microbial contamination in water. However, disinfectants may generate toxic by-products, and even minor damage or biofilm formation on filtration membranes can lead to a heightened risk of microbial contamination. Consequently, how to quickly and safely disinfect microbial contaminated water sources remains a huge challenge. In this study, the high-strength broad-spectrum antibacterial CNF/CS composite membrane was fabricated by utilizing cellulose nanofibers (CNF) to reinforce the structure of chitosan (CS). The resulting CNF/CS composite membrane exhibits an impressive tensile strength of 148 MPa and boasts an active chlorine content of 5.29 %. Notably, even after undergoing 50 washing cycles and 10 repeated chlorination procedures, the structural integrity and high active chlorine content of the composite membrane remain preserved, validating its exceptional strength, stability, and chlorine rechargeability. Additionally, the CNF/CS antibacterial materials demonstrate remarkable attributes in terms of rapid sterilization, sustained and consistent release of active chlorine, and efficient inhibition of biofilm formation, demonstrating great potential in efficient, green, and safe sterilization.

An Effective Mitigation System For Chlorine Release From Storage Facilities: An IoT based Practical Approach Using Physical Barriers

An Effective Mitigation System For Chlorine Release From Storage Facilities: An IoT based Practical Approach Using Physical Barriers

Release of Sulfur and Chlorine Gas Species during Combustion and Pyrolysis of Walnut Shells in an Entrained Flow Reactor

The release behavior of sulfur and chlorine compounds into the gas phase of walnut shell particles (WNS) is studied with an entrained flow reactor. Experiments are carried out in nitrogen (N2), carbon dioxide (CO2) atmosphere and under air and oxy-fuel conditions at different temperatures (T = 1000–1300 °C) and stoichiometries (λ = 0.8–1.1). A total of 98.7% of fuel-bound sulfur volatilizes as sulfur dioxide (SO2), carbonyl sulfide (COS) and hydrogen sulfide (H2S) in the gas phase in N2 atmosphere at 1000 °C. As hydrogen chloride (HCl), 37.0% of the chlorine is released at this temperature. In CO2 atmosphere, a similar total release of sulfur and chlorine is observed (1000 °C). With each temperature increment, the release of SO2, H2S and HCl in the gas phase decreases (N2 and CO2 atmosphere). SO2 forms the major sulfur component in both atmospheres. In CO2 atmosphere, higher concentrations of COS were detected than in N2 atmosphere. Air and oxy-fuel combustion conditions show significantly lower SO2, COS and HCl concentrations as in N2 and CO2 atmosphere. No H2S is detected in the gas phase during any of the combustion trials.

Thiol Chlorination with N-Chlorosuccinimide: HCl-Catalyzed Release of Molecular Chlorine and the Dichotomous Effects of Water

Thiol Chlorination with <i>N</i>-Chlorosuccinimide: HCl-Catalyzed Release of Molecular Chlorine and the Dichotomous Effects of Water

Release of chlorine during oat straw pyrolysis doped with char and ammonium chloride

Chlorine is one of the most undesirable elements in agricultural biomass which can cause operating problems during its thermal conversion. Even in low-temperature pyrolysis, chlorine is released in the gaseous phase. Therefore, in order to study the chlorine release during pyrolysis, the following samples were analyzed: oat straw, oat straw doped with char, oat straw doped with NH4Cl, and char doped with NH4Cl. The pyrolysis process of these feedstocks was conducted at 400, 500 and 600 °C under an inert atmosphere, with a short residence time (2 min) for a sample in the reactor. It transpired that the doping of ammonium chloride into oat straw increased the char yield. Doping oat straw with char as well as NH4Cl promoted biochar carbonization. Chlorine release was significantly inhibited when increasing the pyrolysis temperature from 400 to 600 °C for samples of oat straw, oat straw doped with char, and oat straw doped with NH4Cl. In addition, despite the increase in pyrolysis temperature, the percentage of chlorine distributed into the gas phase decreased. Doping oat straw with NH4Cl had a positive effect on increasing the share of furfural (up to 12.9% at 400 °C) in non-condensed gases identified by pyrolysis gas chromatography-mass spectrometry.

Evaluation and Management of Health and Safety Risks of Chlorine Gas in Transportation Routes

Background: More than 90% of goods movement in Iran is done by road transport. A significant part of these materials is dangerous goods. Considering that chlorine gas is considered a toxic and oxidizing substance, predicting the way of release and mortality due to accidental leakage of chlorine gas can be a crucial tool in adopting preventive strategies. This study aims to evaluate the safety of chlorine gas transportation and analyze the consequences of its release. Materials and Methods: This cross-sectional-analytical study was conducted in 2020 in Tehran. The transportation risk rating index was used to measure and evaluate the quantitative risk of transportation of hazardous materials. PHAST software was used to determine the consequence of possible accident scenarios on the transportation route. In the final stage, according to the amount of traffic, the time and manner of response to emergencies by the fire and emergency organization were simulated using Pathfinder software. Results: In this evaluation, the chlorine risk rating was calculated as 192. The worst possible scenario was a catastrophic rupture of chlorine in the second half of 2021. As a result of the accident, up to a radius of 1800 m from the center of the leak, the dangerous concentration is equal to 20 ppm, that is, equal to the ERPG3 limit. The simulation results showed that the release of poisonous chlorine gas leads to the death of 10% of people up to a radius of 192 m around the scenario. Conclusion: In the scenario of the sudden release of chlorine, in which people need to escape and move away from the accident site, it was found that it takes more than 24 minutes to leave the ERPG-3 area. Considering that the assumed average speed of 1.15 m/s is the average speed of people and naturally the speed of sensitive people is much lower in the conditions of an accident, it can be concluded that in the scenario of a sudden leak, a significant part of the people involved in the accident may suffer severe and irreparable damage.

Comparative study on pyrolysis behaviors and chlorine release of pure PVC polymer and commercial PVC plastics

The organic and inorganic additives in PVC plastics cause great difficulties in their actual recycling process, which are different from pure PVC polymer (PVC-PO). In this study, PVC-PO and two commercial PVC plastics were selected and their differences in structure, pyrolysis behavior, chlorine release and migration were compared by FTIR, TG-MS and a fixed-bed pyrolysis reactor. There were more oxygen-containing functional groups and aromatic compounds in the commercial PVC plastics than PVC-PO because of the addition of foaming agents, flame retardants and lubricants. The thermal weight loss of the commercial PVC plastics was divided into three stages due to the decomposition of additives and the releases of CO2 gas, while that of the PVC-PO was two. The pyrolysis tar of two PVC plastics contained 35.72% and 15.71% oxygenated compounds, respectively, while that obtained from PVC-PO contained 96.46% of aromatic compounds. In addition, calcium additives in PVC plastics could promote the cracking of heavy constituents in the volatile, which was favorable for the formation of more light fractions in tar. The pyrolysis gas of PVC-PO was mainly composed of H2 and C1-C4 hydrocarbon gases, while that of PVC plastics contained about 50% of CO2, followed by H2 and hydrocarbon gases. The chlorine content of the PVC-PO (55.88 wt.%) was higher than that of the PVC plastics (13.83 wt.%, 22.77 wt.%). Most of the chlorine in the three PVC samples released as HCl at 220–370 °C, while the peak temperature of dechlorination of the PVC-PO delayed about 8 °C compared to that of PVC plastics and small part of HCl also released at around 475 °C in the pyrolysis of PVC-PO. About 99.90 wt.% of the chlorine was distributed in the gas phase after PVC-PO pyrolysis, while there were 99.85 wt.% and 97.85 wt.% of chlorine was detected in the gas products of two PVC plastics.

Effect of granulation on chlorine-release behavior during municipal solid waste incineration.

The preparation of refuse-derived fuel (RDF) is an effective and simple means of rural municipal solid waste utilization. The release of chlorine during RDF combustion is important as it causes high-temperature corrosion and pollutants emission such as HCl, dioxins, etc. In this paper, constant-temperature and increasing-temperature combustion experiments were carried out using an electrically heating furnace to analyse the effects of granulation (pressure and additives) on the release of chlorine in particles. During the constant-temperature combustion below 800 °C, only organic chlorine was released from the RDF. The increase of granulation pressure from 1 MPa to 10 MPa did not affect the total amount of chlorine release, but delayed the organic chlorine release by increasing the gas diffusion resistance. During the constant-temperature combustion above 900 °C, inorganic chlorine was released as well. The increase of granulation pressure enhanced the inorganic chlorine release significantly by promoting the reactants contact. During the increasing-temperature combustion, the increase of granulation pressure delayed the organic chlorine release as well but inhibited the inorganic chlorine release. This was mainly attributed to the slow temperature rise to 900 °C, during which the inherent calcium in the RDF reacted with silicon and aluminium, resulting in less reactants for an inorganic chlorine release reaction. Three calcium-based additives were used to inhibit chlorine release. CaCO3 showed no dechlorination effect, and CaO showed better dechlorination effect than Ca(OH)2. For the constant-temperature combustion at 900 °C, the addition of CaO with a Ca/Cl ratio of 2 achieved a dechlorination efficiency of over 90%, with little influence from the granulation pressure. For the increasing-temperature combustion, the granulation pressure had a significant influence on CaO dechlorination effectiveness. Only at a granulation pressure as high as 10 MPa, did the addition of CaO with the Ca/Cl ratio of 2.5 achieve a dechlorination efficiency of 95%.

Antimicrobial dichloroisocyanurate-salts for controlled release of chlorine.

Sodium dichloroisocyanurate (Na-DCC), a disinfectant known for rapid decomposition in water, loses its effectiveness with complete release of free available chlorine (FAC) in under an hour. To overcome this, a series of chlorine rich transition metal complexes/tetrabutylammonium (TBA) salts of DCC, including 2Na[Cu(DCC)4], 2Na[Fe(DCC)4], 2Na[Co(DCC)4]·6H2O, 2Na[Ni(DCC)4]·6H2O, and TBA[DCC]·4H2O have been developed for extended chlorine release studies. The DCC-salts are synthesized based on the metathesis reaction process and are characterized using IR, NMR, CHN analyses, TGA,DSC, and Lovi bond colorimeter. The DCC-salts displayed poor water solubility and low decomposition chlorine release profile compared to Na-DCC. The water solubility of DCC-salts was reduced by a factor of 5.37 to 2500 compared to Na-DCC. The decomposition release of FAC from DCC-salts has been studied over time in comparison to Na-DCC in distilled water using a Lovi-bond colorimeter. DCC-salts displayed controlled FAC release profiles that varied from 1-13 days depending on the type of metal/TBA unit in them, whereas the parent Na-DCC displayed complete FAC release in about 0.91 h. For a proof of concept, the controlled release of metal from one of the DCC-metal complex salts, i.e., copper from the Cu-DCC is also investigated with a function of time in distilled water at RT. The 100% release of copper from Cu-DCC was identified over a period of 10 days. In addition, the applicability of DCC-salts as excellent antiviral agents against the bacteriophage T4 and antibacterial agents against Erwinia, Pseudomonas aeruginosa PA014 (Gram-negative), and Staphylococcus epidermidis (Gram-positive) compared to Na-DCC has been demonstrated.

A multi-step predictive model for the release and transformation of K-Cl-S-containing species from biomass

The release of inorganic elements, especially K, Cl, and S, can cause severe damage to biomass conversion devices, such as slagging, fouling, or corrosion. A predictive model for the release of K-Cl-S elements can be used to enhance the design and operating conditions of biomass conversion devices. In this study, a detailed model is developed that includes 12 solid species and 13 reactions, which can represent the main pathways of the release of K-Cl-S from the particle. The model is coupled to a particle model to predict the release of potassium from different types of biomass at various operating conditions. First, the types and solubility of the potassium after pyrolysis and combustion at different temperatures are compared with the experimental data from the literature. The model predictions of the H2O-soluble, NH4AC-soluble, stable, and total potassium are comparable to the experimental data. Second, the K, Cl, and S in two types of biomass with high and low Si content are studied and compared with the experimental data. The model is used to explain different stages of potassium, sulfur, and chlorine release, which were observed in the experiments. Finally, the concentration of gas-phase potassium-containing species, i.e., atomic K, KCl, and KOH, downstream of burning biomass particles at different temperatures are investigated and compared with experimental measurement. The model can capture the release behavior of these species at different temperatures with good accuracy. The model results are summarized to create a clearer picture of the pathways of K-Cl-S-release from biomass and their interactions with other ash elements.

Газоподібний хлор: молекулярні механізми токсичності, клінічні прояви, діагностичні біомаркери та сучасна лікувальна стратегія

The hostilities on the territory of our state are accompanied by the destruction of the infrastructure of cities and industrial enterprises, which critically increased the risk of toxic gas emissions (including chlorine) and the occurrence of mass poisoning. Aim. To summarize modern knowledge about the molecular mechanisms of chlorine gas toxicity, clinical biomarkers of the toxic process, and modern treatment strategy. Material and Methods. Information data of the Ministry of Health of Ukraine, the State Emergency Service of Ukraine (SES of Ukraine), the American Health Service (CDC), the American Association of Poison Control Centers (AAPCC), materials of scientific libraries PubMed, Medline, Elsevier. Content analysis, systematic and comparative analysis were used. Results and their Discussion. Chemical accidents with the release of chlorine and the occurrence of mass poisonings are registered in various countries. Until now, the mechanisms of the toxic action of chlorine remain completely unstudied, especially at the level of intracellular structures. The results of recent studies demonstrate that irritant and irritant-necrotic effects are not directly caused by chlorine molecules, but by their hydration products – hydrochloric and hypochlorous acids. These acids directly provide a high production of reactive superoxides and nitrogen oxidants, which form oxidative stress in the epithelial cells of the mucous membrane of the bronchopulmonary structure in deeper tissues. The destruction of the cells of the ciliated epithelium occurs, the functioning of ion channels is disturbed and the permeability of cell membranes increases, inflammatory reactions develop: hyperemia, edema, bronchospasm, and surfactant destruction. These processes are facilitated by a massive release of biologically active substances – proinflammatory cytokines – IL-1β, IL-6, IL-18, nuclear factor (NF-KB), 8-isoprostane and tumor necrosis factor (TNF-β) – one of the main biomarkers of oxidative stress. These processes cause: damage to intracellular structures – mitochondria; imbalance in the functioning of the signaling molecule cAMP and disruption of autophagy processes; a decrease in the energy potential of cells with the development of endothelial dysfunction, a violation of the vascular mechanisms of NO homeostasis, both in the cells of the respiratory tract and outside the lungs, which contributes to anatomical damage and impaired function of the organs of the cardiovascular system and kidneys. Conclusion. The mechanism of the toxic action of chlorine at the level of intracellular structures undoubtedly requires further study. Another relevant direction of research may be the search for new sensitive biomarkers of the toxic process, which will allow us to objectively assess the severity of poisoning and increase the effectiveness of the rather complex process of treating patients, in the absence of antidotes. Key Words: chlorine gas, toxicity, mechanism of action, acute poisoning, treatment of poisoning.