Iodine from brown algae in human nutrition,with an emphasis on bioaccessibility,bioavailability, chemistry,and effects of processing: A systematic review

Brown algae are becoming increasingly popular as a food source and dietary supplement in Europe and other Western countries. As they are highly rich in iodine, they represent a potential new dietary iodine source. Iodine deficiency has been re-emerging in Europe, and it is important to ensure adequate intake through one's diet. However, macroalgae, and especially brown algae, may contain very high amounts of iodine, and both iodine deficiency and excessive iodine may increase the risk of negative health effects. The iodine content of algae or foods containing algae is currently not regulated in the European Union. The aim of this paper is to review the literature to determine the chemical species of iodine in brown algae, the loss of iodine during processing, and the bioavailability and bioaccessibility of iodine. A systematic search of the literature was performed in April 2021, via the databases Web of Science and PubMed. The review includes studies of iodine in brown macroalgae in relation to bioavailability, bioaccessibility, processing and speciation. A meta-analysis was conducted in relation to the following topics: (i) the correlation between total iodine and iodide (I^–) content in brown algae; (ii) the correlation between the loss of iodine during processing and the I^– content; and (iii) the correlation between bioavailability and the I^– content. The bioavailability of iodine from brown algae was generally high, with in vivo bioavailability ranging from 31% to 90%. The in vitro bioavailability of iodine (2%–28%) was systematically lower than in vivo bioavailability (31%–90%), indicating an inadequate in vitro methodology. Processing may reduce the iodine content of brown algae, and a higher I^– content was positively correlated with increased iodine loss during processing. Although processing strategies may reduce the iodine content of brown algae significantly, the iodine content may still be high after processing. These findings may be used in food safety evaluations of brown algae as well as in the development of macroalgae-containing foods with iodine contents suitable for human consumption. Further research on processing techniques to reduce the iodine content in brown macroalgae are warranted.     

Study on Adsorption Behavior of Rare Earth Complexes on Nanometer-Size Titanium Dioxide with ICP-AES

Inrecentyears ,rareearthelements (REEs)havebeenwidelyusedinfunctionalmaterials ,cata lystsandotherproductsinindustry ,diagnosisreagentsofmagneticresonanceimaging (MRI)inmedicineandsomefertilizersinagricultureespeciallyinChina .However,asaresultoftheirusage ,moreandmoreREEsaregettingintotheenvironment,andalsointohumanbodyviafoodchain[1,2 ] .Itisnotclearwhetherrareearthelementsareessentialforman ,soitisveryurgenttostudythebiologicaleffectofrareearthelementsinhumanhealthandenvironment .Inthes…     

Predictive modeling of mercury speciation in combustion flue gases using GMDH-based abductive networks

Modeling mercury speciation is an important requirement for estimating harmful emissions from coal-fired power plants and developing strategies to reduce them. First-principle models based on chemical, kinetic, and thermodynamic aspects exist, but these are complex and difficult to develop. The use of modern data-based machine learning techniques has been recently introduced, including neural networks. Here we propose an alternative approach using abductive networks based on the group method of data handling (GMDH) algorithm, with the advantages of simplified and more automated model synthesis, automatic selection of significant inputs, and more transparent input–output model relationships. Models were developed for predicting three types of mercury speciation (elemental, oxidized, and particulate) using a small dataset containing six inputs parameters on the composition of the coal used and boiler operating conditions. Prediction performance compares favourably with neural network models developed using the same dataset, with correlation coefficients as high as 0.97 for training data. Network committees (ensembles) are proposed as a means of improving prediction accuracy, and suggestions are made for future work to further improve performance.     

Speciation of the semivolatile hydrocarbon engine emissions from sunflower biodiesel

Biodiesel fuel is a very attractive alternative to conventional fuel and its effects in the engine performance and regulated emissions have been widely studied. However, the impact on unregulated individual compounds or chemical characteristics of exhaust emissions is not fully characterized. In this paper, the semivolatile fractions of the exhaust emissions of biodiesel blends and conventional fuel have been speciated. The results show great differences between the compounds emitted, especially regarding oxygenated and aromatic species. Likewise, there is a clear relationship between speciated hydrocarbons and other important emissions such as total hydrocarbons (HC), particulate matter (PM), volatile organic fraction (VOF) and mean particle diameter (Dm) of PM.     

腐解稻草DOM提取液洗脱六价铬污染土壤试验研究

工矿企业产生的铬渣、含铬废水由于管理不善导致土壤铬污染严重,迫切需要寻求低成本铬污染土壤修复技术。提出腐解稻草中溶解性有机质（Dissolved Organic Matter, DOM）提取液洗脱铬污染土壤的技术,通过实验室模拟试验,以2种铬污染土壤（总铬含量为分别为121.54、941.90 mg/kg,六价铬含量分别为119.90、856.90 mg/kg）为研究目标,采用振荡淋洗法考察了固液比、淋洗时间、淋洗次数等因素对土壤中总铬、六价铬洗脱效果的影响,并探讨了淋洗前后铬形态变化及淋洗后土壤残留六价铬的持续钝化能力。研究结果表明：稻草经35 d腐解后的DOM提取液洗脱土壤中铬效果最佳,确定为最佳淋洗剂;固液比1：15、淋洗4h/次、淋洗2次为最佳淋洗工艺条件,该条件下,2种铬污染土壤总铬分别洗脱了47.79%、85.92%,六价铬含量分别削减了51.76%、95.09%;DOM提取液呈弱碱性,包含大量羧基、羟基及酚类物质,对水溶态、弱酸提取态和残渣态铬有较好的洗脱效果,有效降低了土壤环境风险,且能持续钝化淋洗后土壤中残余的六价铬。     

高汞煤燃烧过程中汞的析出规律试验研究

针对3种中国典型的高汞煤,利用马弗炉和管式试验炉进行了燃烧温度、燃烧时间等条件因素影响燃煤汞的析出及形态迁移转化的试验研究。研究表明,燃烧条件下加热时间对典型高汞煤中汞的析出率的影响不明显;高汞煤燃烧后,煤中汞在很短时间内即以气态方式进入烟气,并主要以二价汞(Hg2 )和零价汞(Hg0)形式存在,其形态分布与燃烧温度和煤种有关;随着燃烧温度的升高,烟气中的二价汞含量有逐渐升高和零价汞含量逐渐降低的趋势。     

Antimony Solubility and Speciation in Aqueous Sulphuric Acid Solutions at 298 K

This work is an experimental and theoretical study of antimony speciation and the solubility of Sb₂O₅, Sb₂O₃ and Sb₂(SO₄)₃ at 298 K in aqueous sulphuric acid solutions (0 to 6 kmol/m³). A thermodynamic model was developed to quantify the solubility products and aqueous metal speciation. Main dissolved species were H₃SbO_3(aq) and H₃SbO_4(aq). The solubility of antimony increases with increasing solution acidity and with the presence of hydrogen peroxide in the solution. The following standard equilibrium constants at 298 K were obtained: Log K⁰_(Sb2O5) = 11.7±0.5, Log K⁰_(Sb2O3) = 32±1, and Log K⁰_(Sb2(SO4)3) = 55±2.     

An economic and sensitive method for extracting chromium speciation in airborne inhalable dust,using a green sample treatment coupled with electrothermal atomic absorption

ABSTRACT

A new approach of cloud point extraction CPE procedure is optimized for hexavalent chromium determination in airborne dusts. Triton X-114 is used as a surfactant and 1-(2-pyridylazo)-2-naphthol as a specific complexing agent for the trivalent chromium’s removal from the aqueous phase to isolate hexavalent chromium compounds. The parameters influencing the extraction protocol (pH, surfactant concentration, and temperature are optimized. The obtained detection and quantification limits are 0.1 and 0.4 μg/L, respectively. The linearity is verified, with a regression coefficient close to 0.999 and the extraction recovery exceeds 99%. The method was successfully applied to analyze airborne samples collected from workplaces.     

100MW燃煤电站汞排放及其形态分布

采用安大略法、汞连续测量仪和汞吸附法测量了多种烟气中的汞含量,分析了FGD,锅炉负荷和烟气特性对汞排放和形态分布的影响,计算了汞在燃烧产物中的分布及质量平衡.结果表明,这3种汞测试法的测量结果具有很好的一致性,其相对偏差小于20%,总汞的排放量随着锅炉负荷和煤中汞含量的变化而变化.     

不同污泥中5种重金属总量与形态分析

研究了吉化污水处理厂两个车间排放的污泥中Cu、Zn、Cr、Pb、Cd的含量及形态分布.研究结果表明:采自中和处理车间污泥样品中重金属含量由高到低的顺序是Zn>Cu>Cr>Pb>Cd;采自污泥处理车间污泥样品中重金属含量由高到低的顺序是Cu>Zn>Cr>Pb>Cd.污泥样品中Cu的含量最高,为8487.58 mg/kg;Cd的含量最低,为2.72 mg/kg.BCR形态分析结果表明,2种污泥中Cu主要以可氧化态和残渣态存在;Zn主要以可氧化态和可还原态存在;Cr主要以残渣态存在;Pb的形态分布较为均匀;Cd主要以可还原态存在.