deicing salts
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Separations ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 11
Author(s):  
Qiuhong Xiang ◽  
Kunlun Yang ◽  
Ziwen Chen ◽  
Manman Li ◽  
Yuanqi Zhang ◽  
...  

In order to improve the production efficiency of volatile fatty acids (VFAs) by anaerobic fermentation of food waste and reduce the cost for the production of organic deicing salt (ODS), ceramic microfiltration (MF) membrane separation was applied in the conventional food waste fermenter to build an anaerobic membrane bioreactor (AnMBR). Results showed that the maximum VFA concentration in AnMBR was up to 55.37 g/L. Due to the fact that the MF membrane could realize in situ separation of VFAs, the recovery of VFAs could reach 95.0%; 66.6% higher than that of traditional fermentation reactors. After the application of the MF membrane, more than 20.0% of soluble COD, 40.0% of proteins, and 50.0% of polysaccharides were retained and more than 90.0% of VFAs could be transferred in a timely fashion in the AnMBR system. In addition, the enrichment effect of the MF membrane enhanced enzymatic activities such as protease, α-Glucosidase and acetate kinase, and increased the abundance of some important bacteria for organic acid generation such as Amphibacter, Peptoniphilus and Halomonas, which made a significant contribution to the yield of VFAs. After concentration, evaporation and crystallization, the melting efficiency of obtained ODS can reach more than 90.0% in chloride salts, which was 112.0% of commercial calcium magnesium acetate (CMA). When compared to chloride salts and CMA, ODS was more environmentally-friendly as it can reduce the corrosion of carbon steel and concrete significantly. This study created a new way of converting food waste into a high-value organic deicing agent, realizing the resource utilization of solid waste and reducing the production cost of organic deicing agents.


2021 ◽  
Vol 11 (2) ◽  
pp. 91-100
Author(s):  
Zdenka Křenová ◽  
Zdeňka Chocholoušková ◽  
Vladimír Zýval

The Golden Trail, used for the transport of salt from alpine mines to the Czech Kingdom for centuries, was a crucial ancient trade route in the Central European region. The contemporary road I/4, copying the Golden Trail, plays the same role today. The I/4 is used year round with deicing salt, a common standard, applied for winter maintenance. Deicing salt is often used, even in sections where the I/4 passes through the Bohemian Forest and its protected areas. The effects of applying deicing salts on ecosystems in the region is well documented. In addition to many other effects, high concentrations of salt along the roads cause significant changes in plant communities. Plant species sensitive to salinity disappear and the abundance of halophytes increases. Roads are also trajectories for the migration of neophytes. Seeds or other propagules are transported with cargo or in car tires. In this paper, we present our findings on the pilgrimage of Plantago coronopus, a true halophyte, into the Bohemian Forest. We also describe the species’ colonisation strategy and human measures supporting its successful migration in a region of high conservation value.


Author(s):  
Cristobal Javier Manquehual ◽  
Pål Drevland Jakobsen ◽  
Amund Bruland

AbstractFor road tunnels in most Nordic countries, temporary rock support installed during tunnel excavation usually becomes a part of the permanent rock support. Rock bolts are the most common rock support measure in road tunnels excavated in hard rock, and their conditions over the period of tunnel operation play a significant role in the safety of these tunnels. The rock bolt types and aggressive environmental conditions considered in this research are focused on those used and observed in Norwegian and Swedish road tunnels. Findings elsewhere in similar environments are included to highlight the different kinetics of degradation. Based on the collected data, the corrosion levels in these road tunnels are comparable to those in the most polluted industrial areas. Aggressive groundwater conditions for rock bolts include a groundwater pH below four (which can be caused by sulfuric acid formation due to the oxidation of the mineral pyrite in the rock), marine groundwater, and flowing groundwater with a high concentration of dissolved oxygen. Furthermore, chloride-bearing deicing salts commonly used on roads located in cold climate regions during winter can promote corrosion in rock bolts from the tunnel room. For these environments, this research proposes a lognormal probability function to quantify the expected steel corrosion level for 25, 50, and 100 years of exposure time. The corrosion protection given by cement grouting, hot-dip galvanizing and epoxy coating are also addressed to explore their contributions to the lifespan extension of rock bolts in acidic and chloride-rich environments.


2021 ◽  
Author(s):  
Benjamin John Gray Moulding

Abstract Freshwater biota are at risk globally from increasing salinity, including increases from deicing salts in cold regions. A variety of metrics of toxicity are used when estimating the toxicity of substances and comparing the toxicity between substances. However, the implications of using different metrics is not widely appreciated. Using the mayfly Colobruscoides giganteus (Ephemeroptera: Colobruscoidea) we compare the toxicity of seven different salts where toxicity was estimated using two metrics 1) the no effect concentrations (NEC) and 2) the lethal concentrations for 10, 25 and 50% of the test populations (LCx). The LCx values were estimated using two different models, the classic log-logistic model and the newer toxicokinetic-toxicodynamic (TKTD) model. We also compare the toxicity of two salts (NaCl and CaCl2) for C. giganteus at water temperatures of 4°C, 7°C and 15°C using the same metrics of toxicity. Our motivation for using a mayfly to assess salinity toxicity was because mayflies are generally salt sensitive, are ecologically important and are common in Australian (sub-)alpine streams. Considering 144-hour LCx values, we found toxicity differed between various salts, i.e., the lowest 144-hour LC50 (8 mS/cm) for a salt used by a ski resort was half that of the highest 144-hour LC50 from artificial marine salts and CaCl2 applied to roads (16mS/cm). 144-hour LC50 results at 7°C showed that analytical grade NaCl was significantly more toxic (7.3mS/cm) compared to analytical grade CaCl2 (12.5mS/cm). Yet for NEC values, there were comparably fewer differences in toxicity between salts and none between the same salts at different temperatures. We conclude that LCx values are better suited to compare difference in toxicity between substances or between the same substance at different test temperatures, while NEC values are better suited to estimating concentrations of substances that have no effect to the test species and endpoint measured under laboratory conditions.


2021 ◽  
Author(s):  
Dongdong Wang ◽  
Qi Zhu ◽  
Zipeng Xing ◽  
Lei Fang

Abstract The corrosion inhibitor that is added to chloride deicing salt, whose anti-corrosion and low pollution is great significance. LDHs, calcined at high temperature were used as adsorbents to remove various anionic contaminants and it could reduce the solution's freezing point after adsorbing anions. Therefore, this paper reports the use of calcined LDHs as corrosion inhibitors in deicing salts. We analyzed that the removal ability of chloride ion MgAlFeOx was stronger than that of MgAlOx, reaching 85.50%, and the freezing point was lower than that of MgAlOx, the value was -12.0 °C. At the same time, we also found that CaCl2-MgAlOx and CaCl2-MgAlFeOx significantly reduce the corrosion of carbon steel and concrete compared with chloride salts, and CaCl2-MgAlFeOx has the lowest corrosion degree. Hence, we determined that MgAlFeOx was corrosion inhibitor in chloride deicing salt. The metal molar ratio, synthesis temperature and calcination temperature for preparation of MgAl/MgAlFe-LDHs were determined by XRD and TG-DSC analysis that are 9/2/1, 120 ºC and 500 ºC, respectively. The characteristics of MgAlFeOx after Fe3+ addition were studied in detail by Zeta, XRD, XPS, BET and SEM. The mechanism of corrosion inhibitor’s anticorrosion was determined, which was achieved by adsorption and neutralization.


2021 ◽  
Author(s):  
Wai Ying Lam

Chloride (CI) from runoff containing deicing salts is retained in watersheds after deicing ends, resulting in deleterious effects on aquatic biota. Stormwater management ponds (SWMPs) are known to impact pollutant transport. However, there is little information on what role SWMPs play in the timing and magnitude of CI transport in urban watersheds. This study quantifies the mas of CI retained in two urban SWMPs over varying timescales and the in-stream response to CI-laden pond outflows. The findings suggest that SWMPs likely play a role in watershed-scale CI retention. In the receiving creek, CI pulses corresponded to CI releases from the pond. The results of this study suggest that SWMPs concentrate spatially distributed salt inputs and modify the timing and magnitude of their release to receiving streams. This study will help parameterize the role of SWMPs in watershed-scale CI transport models and geospatial models of salt vulnerable areas.


2021 ◽  
Author(s):  
Wai Ying Lam

Chloride (CI) from runoff containing deicing salts is retained in watersheds after deicing ends, resulting in deleterious effects on aquatic biota. Stormwater management ponds (SWMPs) are known to impact pollutant transport. However, there is little information on what role SWMPs play in the timing and magnitude of CI transport in urban watersheds. This study quantifies the mas of CI retained in two urban SWMPs over varying timescales and the in-stream response to CI-laden pond outflows. The findings suggest that SWMPs likely play a role in watershed-scale CI retention. In the receiving creek, CI pulses corresponded to CI releases from the pond. The results of this study suggest that SWMPs concentrate spatially distributed salt inputs and modify the timing and magnitude of their release to receiving streams. This study will help parameterize the role of SWMPs in watershed-scale CI transport models and geospatial models of salt vulnerable areas.


2021 ◽  
Author(s):  
Chehong Tsang ◽  
Medhat H. Shehata ◽  
Abdurrahmaan Lotfy

The lack of a standard test method for evaluating the resistance of pervious concrete to cycles of freezing and thawing in the presence of deicing salts is the motive behind this study. Different sample size and geometry, cycle duration, and level of submersion in brine solutions were investigated to achieve an optimized test method. The optimized test method was able to produce different levels of damage when different types of deicing salts were used. The optimized duration of one cycle was found to be 24 h with twelve hours of freezing at −18 °C and twelve hours of thawing at +21 °C, with the bottom 10 mm of the sample submerged in the brine solution. Cylinder samples with a diameter of 100 mm and height of 150 mm were used and found to produce similar results to 150 mm-cubes. Based on the obtained results a mass loss of 3%–5% is proposed as a failure criterion of cylindrical samples. For the materials and within the cycles of freezing/thawing investigated here, the deicers that caused the most damage were NaCl, CaCl2 and urea, followed by MgCl2, potassium acetate, sodium acetate and calcium-magnesium acetate. More testing is needed to validate the effects of different deicers under long term exposures and different temperature ranges.


2021 ◽  
Author(s):  
Anthony Alongi

<p>Chlorides from deicing salts attack the steel reinforcement in bridge decks which can ultimately cause delamination and deterioration of the concrete. For transportation agencies, the repair cost from these defects are estimated to exceed $5B per year in USA and make up between 50% - 85% of bridge maintenance budgets. While, the removal and replacement of chloride contaminated concrete is the most long-lasting and cost-effective remediation, few methods exist to determine chloride content in bridge decks. This research describes an entirely new method for determining chloride quantity in bridge decks using ground penetrating radar (GPR) technology and establishes and quantifies the relationship between chlorides in concrete (which cause corrosion of reinforcing steel and delamination of concrete) and the effect on GPR signal propagation. Specifically, it shows that there is a deterministic relationship between radar signal attenuation and the amount of chloride and moisture in bridge deck concrete, and that when moisture content is known it is possible to estimate chloride quantity based on signal loss or attenuation measurements. Our research also demonstrates the practical application of this concept by utilizing GPR along with limited coring (three or more core samples) and laboratory chloride measurements to produce an accurate and quantitative, spatial mapping of chlorides in bridge decks.</p>


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