Production Of Caustic Soda Research Articles

Towards a more sustainable hydrogen energy production: evaluating the use of different sources of water for chloralkaline electrolyzers

Water scarcity is becoming a serious threat for the implementation of energy storage devices based on hydrogen in the inland of dry regions, because of the difficulties in finding appropriate sources of water and the important environmental problem associated with the discharge of rejection saline streams produced during the purification of water. This becomes an opportunity for chloralkaline technology in which the quality of water used is lower than the required in other hydrogen production technologies. This work compares the performance of chloralkaline electrolyzers fed with different solutions of NaCl (from brackish water to brines) with that obtained feeding two natural water samples (seawater and porewater) and three processed waters (rejections streams of the electrodialysis, reverse osmosis of the porewater and a real rejection of the reverse osmosis of a vineyard). All tests were made with a lab-scale 3-D printed cell where, in addition, the performance of Ti/RuO2 and Pb/PbO2 anodes were compared, being always better the results obtained in the tests made with the Ti/RuO2 electrode. Results obtained indicate that efficiencies reached using these alternative sources are lower than those which can be reached using synthetic brines that, in turn, were very near to the standards reached in the chloralkaline industry. In the case of hydrogen production, the maximum values were obtained for seawater, reaching efficiencies proximate to 8.0 mg H2 (Wh)-1. Rejection streams of desalination processes were found to be less efficient, attaining values in the range 2 and 4 mg H2 (Wh)-1. Regarding the production of chlorine and caustic soda, better performances were reached again with seawater (161.7 mg Cl2 (Wh)-1 and 0.092 mg OH- (Wh)-1 ) and with the rejection of the electrodialysis, which also reached sound values of 90.4 mg Cl2 (Wh)-1 and 0.107 mg OH- (Wh)-1. Results obtained are promising and indicate a path that must be further worked for the implementation of a greener water management strategy in the hydrogen -based energy storage technology.

Online neutralization promotes water dissociation equilibrium forward in bipolar membranes to achieve 9.2 mol/L NaOH production

The bipolar membrane electrodialysis is a promising caustic soda production technique by taking advantage of the water dissociation under a reverse voltage bias. However, dissociation equilibrium is easily reached when forward water dissociation is equivalent to the back diffusion of acid and base into the salt chamber. Here, we propose manipulating the water dissociation equilibrium by introducing an online neutralization reaction for acid or base products. The results indicate that the online neutralization of the acid product could promote water dissociation forward in bipolar membranes, leading to an increase in the base yield of 27.7 % and a saving of 43.7 % in time in parallel with conventional operation. The boosting water dissociation via online acid neutralization results in the production of 9.2 mol/L NaOH, the highest recorded base concentration produced by bipolar membrane electrodialysis. The present study provides a simple and unique approach for manipulating the water dissociation equilibrium, suggesting the increasingly crucial role of bipolar membranes in base production.

Intellectual control of the electrolysis process in the production of caustic soda

This article is based on the modeling of the operating mode of the membrane electrolyzer in the production of caustic soda through a neural network. In the course of work, a neural network model of the operation of the electrolyzer element was developed. Neural network software was used to create and train neural networks. The purpose of this work is to create an accurate model of the electrolyzer element using the following tasks was to create: the process of designing optimal structures of neural networks and their training, creating an electrolyzer model by training neural networks, as well as processing the modeling results. As a result of this work, a neural network model was developed, which allows to quickly and accurately calculate the result of the operation of the electrolyzer under any initial conditions.

Energy efficiency analysis of caustic soda production process

The increase in the cost of fuel and energy resources motivates industrial enterprises to introduce new technical solutions for their effective use. At the same time, as a result of the production ac-tivities of industrial enterprises, a significant amount of waste is generated that negatively affect human health and the environment. Such enterprises include caustic soda production plants, the technology of which is associated with the formation of thermal and combustible secondary energy resources in the form of steam, condensate, process water, etc. Such types of resources may be useful to use for the production of thermal energy for the company's own needs, or heating of raw materials or material flows involved in the technological chain. The technology of caustic soda production is considered it this paper, the basic structure of production is discussed, the material balance is given, options for improving the efficiency of energy resources are proposed.

ОЦЕНКА СВЕРХНОРМАТИВНЫХ ПОТЕРЬ ПОЛЕЗНОГО ИСКОПАЕМОГО НА ПРИМЕРЕ РАЗРАБОТКИ ИЗВЕСТНЯКОВОГО МЕСТОРОЖДЕНИЯ

The article presents methodological provisions for the assessment of increased mineral losses during open-pit mining of deposits with difficult mining and geological conditions. As an example, the indicators of mineral losses during the development of the Kostanok site of the Chanvin deposit of limestones used for the production of caustic soda are given. The actual level of losses exce-eding 30 % of the volume of extraction of raw materials has been established. The main reasons for the increased limestone losses compared to the level justified by the project are outlined. It was found that during the detailed exploration of the limestone massif, karst zones and areas with a high clay content, lying in the form of «veins» in areas of increased fracturing, were not identified. As a result, as a result of blasting, the exploding quarried, clogged areas with pure limestone are mixed, its contamination to values exceeding those allowed by the project, which leads to the loss of balance reserves of minerals during excavation. Recommendations are given for calculating the level of losses during the development of complex faces, which are characterized by the intermittency of rocks with productive limestone strata and karst zones.

Ion injection bipolar membrane electrodialysis realizes over 8 mol/L NaOH conversion from a brine stream

AbstractThe chlor‐alkali process is currently the predominant technology for caustic soda production but has several major challenges, such as enormous energy demand and supply–demand imbalance between NaOH and Cl2 in downstream industries. Herein, we propose a novel ion‐injection bipolar membrane electrodialysis (IJBMED) system that is capable of boosting water splitting in a bipolar membrane with an ultrahigh current density while omittance concentration polarization in anion‐ and cation‐exchange membranes. The results indicate that the IJBMED approach enables one‐step conversion of the NaCl‐containing brine stream into 8.12 mol/L NaOH with specific energy consumption of 0.79 kWh/kg NaOH (23 wt.% → 25 wt.%), compared to 2.15 kWh/kg NaOH (28 wt.% → 30 wt.%) for the chlor‐alkali process. The advantages of low energy consumption and omittance of chlorine emissions suggest that IJBMED might be a promising alternative to the chlor‐alkali process, revealing a new route to reshape the chemical industry for caustic soda production.

Bipolar membrane electrodialysis: A promising paradigm for caustic soda production

AbstractCurrently, a supply‐demand imbalance between NaOH and Cl2 in the chlor‐alkali process places a great burden on the environment. Bipolar membrane electrodialysis (BMED) is a competitive technology to produce acid and base due to its water splitting characteristics. To determine the competitiveness of NaOH production between BMED and the chlor‐alkali method, BMED was evaluated at various current densities with different NaCl concentrations. Results show that NaOH energy consumption in BMED is less than that of the chlor‐alkali method at a moderate salt concentration (<9 wt.%). Interestingly, the stack voltage suddenly increases during the later stage of BMED. It is speculated that the high osmotic pressure surrounding bipolar membranes restrains water transport into the interfacial layer. In addition, economic assessment indicates that BMED has less impact on global warming than the chlor‐alkali process. Overall, the BMED technique is a promising paradigm for base production in an economical and sustainable manner.

E-Chem Education: A Crash Course in Electrochemical Engineering for Caustic Soda Plant Design

The capstone chemical engineering senior process design course at Penn State in spring 2023 tasked students with designing a caustic soda process to partially meet the global demand for commoditized sodium hydroxide. This article disseminates our experience teaching senior chemical engineering students the core tenets of electrochemical engineering in a single class period for designing an electrolytic caustic soda process. In this E-Chem Education article, we relate key concepts found in chemical engineering (such as sizing up a reactor volume), which chemical engineering seniors are adept with, to electrochemical engineering principles (e.g., current density, voltage, and membrane electrode assembly area) for sizing up and costing out a chlor-alkali electrolyzer. Furthermore, we also discuss alternative electrolyzer designs outside the traditional chlor-alkali process, such as oxygen depolarized cathode (ODC) chlor-alkali and bipolar membrane electrodialysis (BPMED), for caustic soda production and the pros and cons of the alternative process designs.

Perspective in resource recovery from reverse osmosis brines: the case for sustainable seawater refineries for small islands

AbstractReverse osmosis has become the dominant technique for desalination while at the same time there is a steady increase in reliance on desalination systems for water production globally. Resource recovery and mitigation of adverse effects from brine discharge are important factors and are increasingly being considered by researchers and industrial actors. The island nation of Aruba, with over 100 years of commercial desalination history, is used as a case study to illustrate the possibilities of shifting from centralized seawater desalination plants to seawater refineries in which freshwater is considered only one of the possible products. We identify possible economic value from desalination plants of medium scale (as is the case in Aruba) from the production of magnesium, caustic soda, chlorine‐based products and rubidium and possible energy recovery possibilities through osmotic gradients and/or hydrogen storage while at the same time highlighting the insufficient potential for lithium harvesting from seawater desalination brines. We have found that the economic value from resources recovered from brine may be even larger than the value of the freshwater produced by these plants. Furthermore, reduction of salinity and quantity of brine can reduce the overall ecological impact from current brine effluents. © 2023 Society of Chemical Industry (SCI).

НАУЧНО-ПРАКТИЧЕСКИЙ МЕХАНИЗМ ЭКОНОМИЧЕСКОЙ ОЦЕНКИ ПРИМЕНЕНИЯ ТЕХНОЛОГИЧЕСКИХ СХЕМ В ЛОГИСТИЧЕСКИХ МУЛЬТИМОДАЛЬНЫХ СИСТЕМАХ

The industrial sector of Russia is the most important segment of the country's economy. The modern chemical industry has well-established technologies for the production of high-quality caustic soda. Caustic soda is widely used in various production segments, including: chemistry and petrochemistry, metallurgy, gas, food, textile, pulp and paper industry. The unstable economic situation in the world has stopped the action of freight traffic flows in the logistics systems and led to an increase in prices for raw materials. Many countries have started searching for import substitution of raw materials and goods against the background of a sharp break in import supplies. The "leading chemical enterprise" in the Volgograd region is engaged in the production of chemical products. The main volumes of the company's foreign supplies accounted for Europe and Asia. The paper studies the unevenness of foreign supplies in recent years (2020-2021). The characteristic of the links of the logistics system for the transportation of chemical products along the routes "Volgograd – Bishkek" and "Volgograd – Netherlands" is obtained. The time economic costs in the links of multimodal logistics systems are calculated. International routes for the transportation of chemical products to Kyrgyzstan and the Netherlands have been compiled. The effective modes of operation of drivers of automobile transport are determined. Technological schemes for the transportation of caustic soda from Volgograd to Bishkek, using reverse loading of motor transport, have been developed, ensuring a reduction in transport costs.

Liquid-diffusion electrode with core-shell structured mixed metal oxide catalyst for near-zero polarization in chlor-alkali electrolysis

Chlor-alkali electrolysis is a key industrial process for the production of chlorine gas, caustic soda, and hydrogen fuels. Here, we demonstrate that a Ti foam electrode, which has a diffusion layer of liquid reactant, deposited with a thin layer of core/shell-structured mixed metal oxide nanoparticles enables almost zero polarization in the range of hundreds of mA cm−2 towards the chlorine evolution reaction (CER), using noble-metals 20 times lower than commercial electrode. The fast charge-transfer kinetics induce near-zero overpotential at low current densities, while the high mass transport rates aided by porous channels lead to unprecedentedly high CER performance (LSV derived overpotentials of 9 and 44 mV at 10 and 500 mA cm−2 with Faradaic efficiency of 99.1% and 86.1% in 5.0 M NaCl). Under practical chlor-alkali process conditions, the RNTO/Ti foam exhibited remarkable performance as a bifunctional electrode for CER and hydrogen evolution reaction (HER) with overpotential of 11 mV for HER.

LABORATORY AND OPERATING TESTING OF HIGH-ALLOY STEEL PIPES MADE BY THE LATEST TECHNOLOGIES

The purpose of the research: evaluation of the quality and durability for pipes made of high-alloyed austenitic and ferritic-austenitic steels, which are manufactured at PJSC "CENTRAVIS PRODUCTION UKRAINE" using the latest technologies, by conducting complex laboratory studies and long-term operational tests at chemical industry enterprises. Materials and methods: the research materials were experimental pipes made of high-alloyed austenitic and ferritic-austenitic chromium-nickel-molybdenum steels of the new generation, manufactured using the latest technologies. The microstructure of the pipes was investigated by metallography and electron microscopy using developed and improved methods. Corrosive researches in laboratory terms included a test on firmness against the local types of corrosion inherent in high-alloy steels: intergranular corrosion (IGC), pitting corrosion (PC), corrosion cracking (CC) and sulfide stress corrosion cracking (SSCC). The mechanical properties of the pipes were determined by tensile and impact bending tests. Long-term operational tests of pipes were carried out in conditions of industrial production at chemical industry enterprises in apparatus for the urea and caustic soda production. Research results: A high content of special low-energy grain boundaries in the theory of coincident nodes’ lattices (SG CSL) was established in the structure of pipes manufactured according to the latest technologies (≥ 75 %); high resistance of pipes against various types of the most dangerous local corrosion compared to existing analogues, a high level of mechanical properties, as well as high corrosion resistance during long-term operational tests in environments at chemical industry enterprises. The implementation of the obtained results will contribute to increasing the efficiency of production and operation for highly alloyed steel pipes in demand on the world market and increasing the competitiveness of domestically produced pipes on the European and world markets.

A comprehensive multi-scale model for bipolar membrane electrodialysis (BMED)

Bipolar membrane electrodialysis (BMED) is a technology combining solute and solvent dissociation to produce chemicals. In the recent decades, it has been typically studied for the production of valuable acid and base solutions from salt streams. Although many works have been devoted to the experimental investigation of BMED, only a few efforts have focused on its mathematical modelling. In the present work, a comprehensive process model based on a multi-scale approach with distributed parameters is presented for the first time. Five models related to four different dimensional scales were fully integrated to form a comprehensive tool. The integrated model was developed by using the process simulator gPROMS Model builder and was based on a semi-empirical approach combining high prediction accuracy and low computational demand. Once validated through a wide range of experimental data, the model capability was shown by carrying out a broad sensitivity analysis assessing the performance of the BMED technology for industrial-scale applications. Results showed how the performance of a BMED unit changes with both varying process conditions and the installed membrane area. Particularly, the non-ideal phenomena that reduce the produced NaOH concentration and increase the energy consumption were thoroughly investigated. Finally, this study demonstrated that a Levelized Cost Of Caustic Soda of about 280 € ton-1NaOH can be obtained, thus making this technology a possible candidate for the industrial production of caustic soda from brines in the future.

Obtaining Caustic Soda and Burkeite by Caustification of Mixture of Corbonate and Sodium Sulphate

The optimal technological parameters for the production of caustic soda from sodium carbonate and sulfate and calcium hydroxide have been established. The influence of the concentration of lime milk on the rate of filtration by sediment and filtrate has been studied.
 Purpose of the Work: The purpose of this work is to determine the physicochemical basis for the production of sodium hydroxide and burkeite by causticization of sodium carbonate and sulfate.
 Scientific Novelty: In comparison with the known works, a theoretical profoanalytical analysis of the one-cation of four-component system and its constituents was carried out for the first time, and also determined the optimal technological parameters of causticization of solutions for local carbonates and sodium sulfates.
 Features of the Work:
 - the influence of the main technological parameters on the processes of causticization, filtration, evaporation;
 - research of intermediate and finished products by modern physicochemical methods;
 - study of the rheological properties of the solution depending on the temperature and concentration of the resulting solutions.

Caustic Soda Production, Energy Efficiency, and Electrolyzers

ADVERTISEMENT RETURN TO ISSUEPREVViewpointNEXTCaustic Soda Production, Energy Efficiency, and ElectrolyzersAmit Kumar*Amit KumarDepartment of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, United States*Email: [email protected]More by Amit Kumarhttps://orcid.org/0000-0001-7807-3427, Fengmin DuFengmin DuDepartment of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, United StatesLaboratory for Physical Chemistry, ETH Zurich, CH-8093 Zurich, SwitzerlandMore by Fengmin Duhttps://orcid.org/0000-0002-8164-7628, and John H. Lienhard V*John H. Lienhard VDepartment of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, United States*Email: [email protected]More by John H. Lienhard Vhttps://orcid.org/0000-0002-2901-0638Cite this: ACS Energy Lett. 2021, 6, 10, 3563–3566Publication Date (Web):September 15, 2021Publication History Received27 August 2021Published online15 September 2021Published inissue 8 October 2021https://doi.org/10.1021/acsenergylett.1c01827Copyright © 2021 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1621Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSUBJECTS:Radiology,Electrodes,Membranes,Electrical energy,Selectivity Get e-Alerts

NaCl recovery from organic pollutants-containing salt waste via dual effects of aqueous two-phase systems (ATPS) and crystal regulation with acetone

A large amount of salt waste accompanied with contaminants (e.g., organic pollutants) is produced in chemical production process, causing serious environmental hazards and waste of salt resources. However, there have been few satisfactory treatments for this hazardous waste until now. In this work, a novel strategy for NaCl recovery and organic pollutants removal from the salt waste containing pyridine derivatives was developed by using acetone in salt waste solution. The results showed NaCl was effectively recovered (recovery rate, 99.12%), and the TOC value of its saturated solution was reduced from 806.2 to 145.4 mg/L, below the limits (200 mg/L) for chlorine gas and caustic soda production in chlorine alkali plant. Moreover, no pyridine derivatives can be identified through Fourier transform infrared spectroscopy (FTIR) test. Mechanism analysis demonstrated the dual effects of acetone as following: 1) acetone and NaCl formed aqueous two-phase systems (ATPS) to remove organic pollutants; 2) acetone, as a crystal regulator, induced NaCl crystals to recrystallize in cubic morphology with a smooth surface, which enhanced the removal of pollutants. Besides, the acetone-water phase split facilitated the separation of organic pollutants as well as the reuse of acetone. This work proposes a promising and feasible method for salt waste to remove organic pollutants and recover recrystallized NaCl solids, and also provides new insights into the function of acetone on the crystal regulation of salts.

Investigation of the influence of chlorine-containing disinfectant type on the quality of drinking water and the effectiveness of water treatment technology

Introduction. Effectiveness and applicability of chlorine-containing disinfectants used in the practice of water treatment were studied for the purpose of solving urgent environmental problems associated with the formation of secondary pollutants generated during the chlorination of natural water. Such contaminations are mostly represented by organohalogen compounds producing strong negative effect on the physiological state of living organisms, including human beings. To solve this problem, it is proposed to use technical grade sodium hypochlorite instead of traditional liquid chlorine when selecting disinfectants for natural water. Technical grade sodium hypochlorite is obtained by saturating solutions of diaphragmatic sodium hydroxide with chlorine gas at the stage of liquefaction of chlorine and caustic soda production. Sodium hypochlorite solution is significantly less toxic, non-flammable and not explosive. Materials and methods. A comparative study was conducted as to changes in the content of organohalogen compounds and heavy metals in water treated with sodium hypochlorite and liquid chlorine of one year duration. Analyses of water samples of water treated with liquid chlorine and sodium hypochlorite were made to measure concentrations of heavy metals, organohalogen compounds and other drinking water quality indicators, as specified by current regulations. Results. The obtained data demonstrate that the use of sodium hypochlorite for disinfection provides a higher quality of drinking water, therefore, it is advisable to replace liquid chlorine with technical grade sodium hypochlorite in the process of water treatment as potable water. Conclusions. The results of the study formed the basis for numerous industrial tests and subsequent implementation in existing water treatment plants in many large cities of Russia.

Removal of iodine from the salt water used for caustic soda production by ion-exchange resin adsorption

A lower concentration of iodine (<0.2 mg/L) in the salt water used for caustic soda production is crucial to prolong the service life of ionic membrane and decrease the cost of production. The removal of iodine from salt water by resin adsorption was carried out in this work. It was found that the existing species of iodine is the key factor to affect the adsorption, and I2 is the optimal adsorbed species in salt water through the reaction between I2 and Cl− in the resin to form (ClI2)−. A simple pre-treatment method was developed to transform different iodine species in salt water into I2 by adjusting the solution to pH 1.5–2.5 and redox potential (Eh) 530–560 mV. A novel purification system for the removal of iodine from salt water was subsequently developed and constructed based on the pre-treatment method and the adsorption thermokinetics of I2. The stability and reliability of this developed method and system were demonstrated by a scale-up experiment to remove iodine from the refined salt water used for caustic soda production, by which the concentration of iodine can be stably decreased to far <0.2 mg/L.

Global and regional trends in mercury emissions and concentrations, 2010–2015

Mercury (Hg) is a naturally occurring element in the Earth's crust. It can be harmful to human health when released in large quantities and/or converted to the neurotoxicant methyl mercury in aquatic ecosystems. This study analyzes global and regional trends in anthropogenic Hg releases to the atmosphere between 2010 and 2015, as well as the associated trends in modeled and measured Hg concentrations at sites around the world. In general, we find that global Hg emissions and concentrations have grown slightly in this period, as declines from the phase-out of commercial Hg use in the developed world have been more than matched by increases in Hg-related activities in the industrializing countries of the world. We estimate that global Hg emissions between 2010 and 2015 have grown at a rate of 1.8%/yr, from 2188 Mg (+44%/-20%, 80% C.I.) in 2010 to 2390 Mg (+42%/-19%, 80% C.I.) in 2015. Regionally, emissions declined over this period in the U.S. (−10%), OECD Europe (−5.8%), and Canada (−3.2%), while they increased in Central America (+5.4%), South Asia (+4.6%), and Eastern Africa (+4.0%). East Asia remained the largest emitting region at 1012 Mg in 2015, though growth there has slowed significantly in recent years. The production of Hg (+7.9%), caustic soda (+6.3%), and cement (+6.3%) showed the highest increases by source type, though artisanal and small-scale gold mining (ASGM) was the single largest source of emissions in 2015 (775 Mg). The commercial use of Hg in dental applications (−5.6%) and electrical equipment (−5.2%) continued to decline. These emission trends show a continuation of the regional and sectoral shifts that began in the 1970s, but with a resulting reversal in global trends, because the benefits from Hg phase-out in North America and Europe have been largely realized and industrial growth in developing countries has begun to dominate. The emission trends are in agreement with trends in modeled and measured concentrations, which show small declines in surface air total gaseous Hg concentrations in eastern North America and Western Europe between 2010 and 2015, but slight increases for much of the rest of the world, driven by the continued increases in emissions from Asia and from ASGM. Our results suggest that reductions of Hg in the North Atlantic region have been largely successful, and focus now needs to shift to Asia and to the continued practice of ASGM worldwide.

Larch Tree Rings as a Tool for Reconstructing 20th Century Central European Atmospheric Mercury Trends.

We propose the tree rings of European Larch ( Larix decidua) as a widely available and reliable geochemical archive of local and regional changes in atmospheric mercury (Hg). Mean Hg concentrations in larch tree rings from 8 background sites across the Czech Republic ranged from 2.2 to 4.8 μg kg-1; the maximum concentrations occurred in the period 1951-1970. At 3 sites impacted by Hg-emission sources [gold amalgamation processing, caustic soda production, and lead (Pb) ore smelting] mean larch tree ring Hg concentrations were significantly elevated relative to background sites. Changes in larch tree ring Hg concentrations were temporally coherent with known activities at the sites that would alter Hg emissions; the nearly simultaneous response in tree rings indicated little or no translocation of Hg within the larch bole. Based on the present-day atmospheric Hg concentration of 1.63 ng m-3 at the intensively monitored Czech Global Mercury Observation System site and the most recent mean tree ring Hg concentration of 2.8 μg kg-1 in co-located larch trees, we developed a simple distribution model of Hg between the atmosphere and larch tree rings. We applied the model using observed changes of Hg in larch tree rings from the countrywide background sites to reconstruct past atmospheric Hg concentrations in central Europe. Modeled Hg concentrations were in agreement with annual means from the European Monitoring and Evaluation Programme observatories.