Ozonation of Sulfur Dioxide in Sulphuric Acid Solution

In this study, the oxidation rates of sulfur dioxide （SO2） in sulphuric acid solution by ozone and oxygen were compared, and the oxidation mechanism of ozone on SO2 was investigated. The results showed that the oxidation-reduction potential of the acidic solution was enhanced, the transformation rate of sulfuric acid to sulphuric acid was increased and the absorption driving force was improved in the presence of ozone. By comparing the amount of sulfate ions measured in the experiments and the theoretical amount of sulfate ions calculated from the amount of ozone consumed in the reaction, it can be confirmed that oxygen free radicals from dissociation of ozone are reactive as an efficient oxidant and oxygen from ozone generator participates in the reaction with SO2. 0.602 mol of effective oxygen was introduced into the reaction by one mole of ozone in 10.15 rain at sulphuric acid concentration of 3% （by mass）, SO2 concentration of 1.33% （by volume） and oxygen flow rate of 1.5 L.min^-1 from ozone generator.

Antitussive activity of Triclisia dictyophylla of the family Menispermecae

Objective:To verify through a scientific mean the therapeutic use of the plant as an anti-tussive agent,by traditional medicine healers and also aid in the search for new drugs developments from plants.Methods:The roots of Triclisia dictyophylla were investigated for their antitussive properties.The plant was uprooted in the month of June 2003 at Igbodo,Delta State,Nigeria and was taken to the university of Nigeria Nsukka for taxonomy. The roots were chopped,ground and immersed in pure drinking water for 24 hours.After filtration, extraction was carried out using a Rotary evaporator,preliminary phytochemistry and acute toxicity studies were carried out.Antitussive study was carried out using a total of 42 young rats of average weight of 72.2 g.The rats were housed in standard animal house of the university and were allowed access to feeds and water but, were fasted for 12 hours prior to commencement of experiment.Specific and appropriate dosage of the crude extract and Codeine re - dissolved in water were administered orally 30 minutes prior to induction of cough. Cough was induced by exposing the animals to Sulphure dioxide gas for 3- minutes.Coughing was taken as number of Head-nods per minute,Stethoscope aided audible sounds and,or tears secretion.Percentage cough inhibition for crude extract and,or Codeine treated rats were compared with reference to control animals.Results were subjected to statistical analysis using SPSS 13.0.Results:A 10.2%extraction yield was got from a starting root initial weight of 320 g.The preliminary phytochemistry of the aqueous root extract revealed the presence of alkaloids,saponins,flavonoids,proteins,reducing sugars,steroids,resins fats/oils and glycosides. The Median lethal dose(LD_(50)) based on Lorke's 1983 method was 548 mg/kg The aqueous root extract at concentrations of 10 mg/kg,50 mg/kg,100 mg/kg and 200 mg/kg orally administered,inhibited cough in rats induced by sulphure dioxide gas by 16.67%,33.33%,50.00%and 83.33%respectively.While Codeine phosphate,a standard antitussive agent,at oral concentrations of 10 mg/kg and 20 mg/kg inhibited cough in rats induced by sulphure dioxide gas by 33.33%and 60.67%respectively.Conclusion:Earlier works by some authors had led to isolation of Morhinian Alkaloids from Triclisia dictyophylla thus most probably linking its mechanism of antitussive activity to that likable of Morphine.This study justifies the use of the plant in treatment of cough by Traditional Medicine Healers.

Preparation of Cs-Rb-V series sulphuric acid catalyst

Cs Rb V series low temperature sulphuric acid catalyst was prepared for the first time by using carbonized mother liquor containing alkali metal salts. The results show that the conversion of SO 2 on catalyst prepared directly with carbonized mother liquor could reach to 24.8% at 410?℃. If n (Na)/ n (V) was adjusted properly, the conversion of SO 2 could be increased to 35.6% at 410?℃. Refined carbonized mother liquor could make the catalytic activity even higher at low temperature, the conversion of SO 2 could be increased to 36.65% at 410?℃. The catalyst was examined with differential thermal analysis. It was found that both endothermic peaks and exothermic peaks of catalyst shifted forward obviously and the catalyst possessed higher activity at low temperature.

An estimate of the conversion rates of SO_2 to SO_4^(2-)- and NO_2 to HNO_(3+) NO_3^- for the evaluation air pollution in Beijing

The conversion rates of SO2 to SO42- and NO2 to HNO3+NO3- are estimated from the field-data obtained in Beijing in summer, 1988. The results show that the conversion rate of NO2 is about four times as much as that of SO2; The conversion rates have a diurnal variation in a day. On the average, the rate of SO2 is estimated to be 4.7% h-1 during the daytime and 3.4% h-1 during the nighttime. Similarly, the rate of NO2 is estimated to be 17.2% h-1 and 12% h-1 respectively.

Exploring the edge of a natural disaster

Natural geological, chronic and acute release of volcanic gases can have a dramatic impact on vegetative ecosystems and potential impact on regional agriculture and human health. This research incorporates a series of observations using leaf level gas exchange, chlorophyll fluorescence and remotely sensed reflectance measurements of vegetation experiencing chronic exposure to volcanic gas emissions;to develop techniques for monitoring the relative health of vegetation along the edge of an acute vegetative kill zone of a natural disaster and potential preeruption vegetation physiology. Experiments were conducted along an elevation gradient that corresponds to the SO2 gradient on vegetation along the south flank of Volcán Turrialba, Costa Rica. This study site is a natural environment with high volcanic degassing activity with significant SO2 emissions (n/d-0.281 ppm). Corresponding to an SO2 gradient, a substantial increase in CO2 concentration of (430-517 ppm) was identified. We further show the physiological interactions of SO2 and CO2 have on vegetation along the kill zone of this natural disaster can be assessed by examining the SO2/CO2 ratios. The physiological indices tested and relationships among measurements emphasized in this research will add to the assessment of the impact atmospheric volcanic gas emissions have on the physiology of surrounding vegetation as well as advance the capability of remotely sensed environmental stress in natural settings.

Comparison of Sulfur Dioxide Residue in Chinese Me-dicinal Materials by Titration-fluorescence Spectrome-try and Pharmacopoeia Method

With sulphur-fumigated Chinese medicinal materials （Fritillaria thunbergii , Isatis #utigotica , Asparagus cochinchinensis and Poria cocos ） as the test materials, sulfur dioxide or sulfite residue was determined by the method in Chinese Pharmacopoeia （2015 edition） and titration-fluorescence spectrometry, respec- tively. The results showed that there were significant differences in measured value between titration-fluorescence spectrometry and phmmacopoeia method. The t result of titration-fluorescence spectrometry was much closer to the actual content of sulfur dioxide in Chinese medicinal materials. Thus, titration-fluo- rescence spectrometry had higher application value

SO₂Oxidation Efficiency Patterns during an Episode of Plume Transport over Northeast India: Implications to an OH Minimum

Systematic monitoring of the fluctuations in atmospheric SO2 oxidation efficiency—measured as a molar ratio of SO42- to total SOx (SOx=SO2+SO42-), referred as S-ratio—have been performed during a major long range plume transport to northeast India (Shillong: 25.67°N, 91.91°E, 1064 m ASL) in March 2009. Anomalously low S-ratios (median, 0.03) were observed during the episode—associated with a cyclonic circulation—and the SO42- and SO2 exhibited unusual features in the ‘relative phase’ of their peaks. During initial days, when SO2 levels were dictated by the long range influx, the SO42- and SO2 variabilities were in anti-phase—for the differing mobility/loss mechanisms. When SO2 levels were governed by the boundary layer diurnality in the latter days, the anti-phase is explained by a ‘depleted OH level’—major portion being consumed in the initial period by the elevated SO2 and other pollutants. Simulations with a global 3D chemical transport model, GEOS-Chem (v8-03-01), also indicated ‘suppressed oxidation conditions’—with characteristic low S-ratios and poor phase agreements. The modelled OH decreased steadily from the initial days, and OH normalized to SO2—referred as OHspecific—was consistently low during the ‘suppressed S-ratio period’. Further, the geographical distribution of modelled OH showed a pronounced minimum over the region surrounding (20°N, 95°E) spanning parts of northeast India and the adjacent regions to the southeast of it—prevalent throughout the year, though the magnitude and the area of influence have a seasonality to it—with significant implications for reducing the oxidizing power of the regional atmosphere. A second set of measurements during January 2010—when prominent long range transports were absent—exhibited no anomalies, and the S-ratios were well within the acceptable limits (median, 0.32). This work highlights the GEOS-Chem model skill in simulating/detecting the ‘transient fluctuations’ in the oxidation efficiency, down to a regional scale.

A Neural Network Algorithm to Detect Sulphur Dioxide Using IASI Measurements

The remote sensing of volcanic sulphur dioxide (SO2) is important because it is used as a proxy for volcanic ash, which is dangerous to aviation and is generally more difficult to discriminate. This paper presents an Artificial Neural Network (ANN) algorithm that recognizes volcanic SO2 in the atmosphere using hyperspectral remotely sensed data from the IASI instrument aboard the Metop-A satellite. The importance of this approach lies in exploiting all thermal infrared spectral information of IASI and its application to near real-time volcanic monitoring in a fast manner. In this paper, the ANN algorithm is demonstrated on data of the Eyjafjallajokull volcanic eruption (Iceland) during the months of April and May 2010, and on the Grímsvotn eruption occurring during May 2011. The algorithm consists of a two output neural network classifier trained with a time series consisting of some hyperspectral eruption datasets collected during 14 April to 14 May 2010 and a few from 22 to 26 May 2011. The inputs were all channels (441) in the IASI v3 band and the target outputs (truth) were the corresponding retrievals of SO2 amount obtained with an optimal estimation method. The validation results for the Eyjafjallajokull independent data-sets had an overall accuracy of 100% and no commission errors, therefore demonstrating the feasibility of estimating the presence of SO2 using a neural network approach also a in cloudy sky conditions. Although the validation of the neural network classifier on datasets from the Grímsvotn eruption had no commission errors, the overall accuracies were lower due to the presence of omission errors. Statistical analysis revealed that those false negatives lie near the detection threshold for discriminating pixels affected by SO2. This demonstrated that the accuracy in classification is strictly related to the sensitivity of the model. The lower accuracy obtained in detecting SO2 for Grímsvotn validation dates might also be caused by less statistical knowledge of such an eruption during the training phase.

Preparation of zeolite NaA for CO_2 capture from nickel laterite residue

Zeolite NaA was successfully prepared from nickel laterite residue for the first time via a fusion-hydrothermal procedure. The structure and morphology of the as-synthesized zeolite NaA were characterized with a range of experimental techniques, such as X-ray diffraction, scanning electronic microscopy, and infrared spectroscopy. It was revealed that the structures of the produced zeolites were dependent on the molar ratios of the reactants and hydrothermal reaction conditions, so the synthesis conditions were optimized to obtain pure zeolite NaA. Adsorption of nitrogen and carbon dioxide on the prepared zeolite NaA was also measured and analyzed. The results showed that zeolite NaA could be prepared with reasonable purity, it had physicochemical properties comparable with zeolite NaA made from other methods, and it had excellent gas adsorption properties, thus demonstrating that zeolite NaA could be prepared from nickel laterite residue.

Preparation of MnO_2 and calcium silicate hydrate from electrolytic manganese residue and evaluation of adsorption properties

Electrolytic manganese residue(EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrate(EMR-CSH). The MnO2 is successfully synthesized from the metal cations extracted from EMR, which can effectively recycle the manganese in the EMR. By the combination of XRD, SEM and EDX analysis, the as-prepared MnO2 is found to exhibit a single-phase with the purity of 90.3%. Furthermore, EMR-CSH is synthesized from EMR via hydrothermal method. Based on the detailed analyses using XRD, FT-IR, FE-SEM, EDX and BET surface area measurement, the product synthesized under the optimum conditions(p H 12.0 and 100 °C) is identified to be a calcium silicate hydrate with a specific surface area of 205 m2/g incorporating the slag-derived metals(Al and Mg) in its structure. The as-synthesized material shows good adsorption properties for removal of Mn2+ and phosphate ions diluted in water, making it a promising candidate for efficient bulk wastewater treatment. This conversion process, which enables us to fabricate two different kinds of valuable materials from EMR at low cost and through convenient preparation steps, is surely beneficial from the viewpoint of the chemical and economical use of EMR.

Female Head, Food Stamps, Ethnicity and Air Pollution: Confounders or Causes of Heart Disease in Texas

One in every four deaths in the United States is attributed to heart disease. While the ethnic variations have not been momentous, the socioeconomic disparities of heart disease incidence need to be further investigated. Moreover, exposure to air pollutants has been documented to cause heart disease. This secondary-data study investigates the effects of air pollutants as well as socioeconomic factors on hospitalization rate of heart disease in Texas. The rates for the five sub-diagnoses of cardiovascular disease, heart attack, stroke, hypertension and heart disease were linked to ozone, fine particulate matter, carbon monoxide, nitrogen dioxide, sulphur dioxide and socioeconomic status factors at the county level. These were college education attainment, households with female heads, percentage of users of food stamps, ethnicities, living near a park and living in houses with severe housing problems. Spatial lag modelling was conducted to estimate the statistical significance of the independent variables on the five sub-diagnoses of heart disease. Fine particulate matter, sulphur dioxide and being African American were significant to all the outcomes. Living in a household with female head was significant to stroke and hypertension. Using food stamps was significant to cardiovascular disease, heart attack and heart disease. Fine particulate matter and sulphur dioxide increase the risk of heart disease by a factor of three to twenty two times, respectively. Whereas low socioeconomic status increases the risk of heart disease by a factor of up to four times. The results of the effect of particulate air and sulphur dioxide pollution among people in low social class especially African Americans. The vicious cycle of heart disease and low socioeconomic status call for societal and policy makers’ attention through methodical interventions to address the two significant issues of industrial facilities site allocation and stationary emission resources.

Emission of Combustible Gases at Traffic and Practising Waste Dumpsite in Freetown, Sierra Leone: A Pilot Study

An assessment of the emission of combustible gases in developing countries requires reliable analytical realtime monitors that can rapidly screen them with minimal handling. Considering the expensive nature of monitoring environmental pollutants, chemical sensors are expected to play a pivotal role in measuring and recording environmental data. The Drager X am 5000 was used to report emission levels of combustible gases in this study, namely;nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO) at traffic and practising waste dumpsite in Freetown, the main city of Sierra Leone. Hourly average values for the three pollutants were recorded in the morning, afternoon and evening periods, respectively. The range of values were 18 - 76 ppb for NO2, 211 - 506 ppb for SO2 and 11 - 14 ppm for CO at traffic site;and 6 - 16 ppb for NO2, 118 - 276 ppb for SO2 and 8 - 15 ppm for CO at the dumpsite, respectively. There were significantly high hourly variations for NO2 and SO2 at the traffic site and for CO and SO2 at the dumpsite. Evidence of peak values showed emission levels that were considered dangerous for human exposure. This pilot study revealed that combustible gases released in certain areas of the capital city are a concern for both public health officials and environmental advocates.

Effect of Heterogeneity of Porous Media on Gas Permeation and Entrapment

Capillary trapping prevents the migration of CO2 in reservoirs due to buoyancy. The residual gas saturation is strongly influenced by the gas saturation after gas injection. In this study, we have investigated the effect of stratified structure of heterogeneous porous media on gas permeation and entrapment. Experiments were carried out at a laboratory condition for a nitrogen-water system with the packed beds of glass beads with various diameters which modeled stratified porous media. In the case of parallel structure, the injected gas selectively percolated into permeable layers. The gas permeation can hardly occur for the less permeable layers because of the capillary entrance pressure. In the case of serial structure, the interface of porous structure hindered the migration of gas across it, because of the capillary entrance pressure. When the gas percolated in the permeable layers, capillary fingering was developed in the layers. However, when the tip of finger reached the interface, fingers grew in tangential directions until the pressure built up to overcome the capillary entrance pressure. As a result, high gas saturation was achieved in the permeable layers of both upward and downward gas injections.

Urban Air Quality Assessment of Kathmandu by Passive Sampling Technique

This paper presents an assessment of air quality of the Kathmandu valley, capital city of Nepal. This is the largest urbanized area in the country of about 300 km2. In the last two decades an intensive development of demographic, traffic and industry growth in the region was observed which was reflected on the air quality degradation. In order to evaluate the urban air quality in Kathmandu, a field monitoring network for particle deposition, nitrogen dioxide （NO2） and sulphur dioxide （SO2） by passive sampling with high space resolution was implemented in co-operation with IVL-Sweden. The net work composed of 60 monitoring sites distributed in a grid of 1 × 1 km2 covering all over the main city and some rural valley. Monitoring were carried out for two seasons, rainy and dry as two campaign monitoring. The diffusive samplers were prepared and analyzed in IVL, Sweden. Good agreements in particle deposition between the two campaigns were observed. The particle deposition to the surrogate surface varied between 3 and 608 μg@cm2·monthl for the monitoring periods. The NOz concentrations on the other hand were quite similar in the two campaigns, and the SO2 concentrations were much lower in the first campaign compared to the second. The ranges of NO2 and SO2 concentrations were found to be from 5.6 to 52.6 μg/m3 and 0.6 to 23.4 μg·m-3 respectively. Arc Info/Arc map GIS 9.2 software was used for production of maps of spatial distribution of all the three parameters in the valley. Seasonal variation and traffic influence were also studied. Local meteorological effects in the distribution of pollutants were clearly observed and the NO2 concentrations were strictly related with traffic intensity.

在线流动-蒸馏法分析药食同源食品中二氧化硫残留量

采用在线流动-蒸馏法测定分析百合、芡实药食同源食品中二氧化硫残留量,采用碱性溶液震荡提取,流动注射法分析了多批次百合、芡实药食同源的二氧化硫残留量,在0.5~10.0 mg/L浓度范围内线性良好,相关系数R2=0.9991,平均回收率97.3%,RSD为2.1%~4.6%,检出限为1.0 mg/kg,定量限为3.0 mg/kg。实验结果与传统蒸馏滴定法比较,两种方法结果没有显著性差异。该方法提取方式简单、耗时短、准确度高,适用于大批量药食同源食品分析检测。

二氧化氯释放膜在鲜切火龙果保鲜中的应用

以亚氯酸钠和柠檬酸为主要原料,制备了气态二氧化氯(ClO_(2))释放膜,并探讨了在4℃下该释放膜对鲜切火龙果抑菌效果、氯残留及营养感官品质的影响。结果表明,在含有ClO_(2)释放膜的包装体系中,ClO_(2)的释放时间为24~28 h,最大释放量达0.44 mg/L。释放膜中亚氯酸钠和柠檬酸含量越高,ClO_(2)释放速率越大、释放时间越短。ClO_(2)释放膜可有效抑制细菌和酵母菌的生长。在经ClO_(2)释放膜处理的鲜切火龙果中检测到氯离子和氯酸盐两种氯残留化合物,其中氯离子含量在贮藏期显著上升,但氯酸盐残留量与对照组的无显著差异,该处理未造成基于氯残留的安全隐患。ClO_(2)释放膜可显著抑制火龙果可溶性固形物含量的下降,在贮藏期8 d时使得可滴定酸含量增加10%左右。ClO_(2)释放膜处理会造成火龙果中维生素C和总酚的损失,其中在贮藏期8 d时维生素C含量下降17%~32%,总酚的损失率可通过减少释放膜中亚氯酸钠和柠檬酸含量显著降低到27%以下。此外,ClO_(2)释放膜可显著抑制火龙果的褐变并降低POD活性。因此,ClO_(2)释放膜能够明显延长鲜切火龙果的贮藏期,使其维持较好品质。

八角茴香中二氧化硫残留量分析及安全性评价

目的 检测预包装与散装八角茴香流通、生产(分装)、餐饮环节中二氧化硫残留量情况,并对其进行安全性评价。方法 在大型商场、批发零售市场、餐饮企业、网络平台等不同领域随机抽取预包装与散装八角茴香90批次、新鲜湿八角16批次,参照GB 5009.34—2022《食品安全国家标准食品中二氧化硫的测定》检测二氧化硫残留量,依据GB 2760—2014《食品安全国家标准食品添加剂使用标准》规定对八角茴香中二氧化硫残留量进行评价分析,并从食品、药品两方面对其进行健康风险评估。结果 90批次八角茴香中二氧化硫残留量超出标准限值的为13.3%,其中预包装和散装八角茴香二氧化硫残留量平均值分别为33.6 mg/kg和93.6 mg/kg,超标率分别为2.5%和22.0%。流通环节、生产(分装)环节和餐饮环节八角茴香中二氧化硫残留量平均值分别为66.3、42.4、90.6 mg/kg,超标率分别为12.5%、8.3%、21.4%。16批次新鲜湿八角中二氧化硫本底值的平均值为9.38 mg/kg。散装八角茴香中二氧化硫残留量高于预包装八角茴香,且散装八角茴香中二氧化硫残留量超标率显著高于预包装八角茴香(X^(2)=7.313,P=0.007)。流通、生产(分装)、餐饮各个环节均存在二氧化硫残留量超标现象,各环节超标率比较差异无统计学意义(X^(2)=1.092,P=0.579)。结论 八角茴香作为食品使用时,各年龄段人群对散装和预包装八角茴香中的二氧化硫暴露风险系数均小于1,但作为药品使用时,低年龄段人群对部分八角茴香中的二氧化硫暴露风险系数大于1,在风险管理上需引起足够重视。在生产、消费、研发等各领域均应加强宣传监管力度,控制八角茴香中二氧化硫残留量,确保八角茴香质量安全。

食药两用物质天麻、灵芝的外源性污染物分析

测定食药两用物质天麻、灵芝的外源性污染物,进行安全性风险评估。采用酸碱滴定法测定二氧化硫残留量,微波消解-电感耦合等离子体质谱法测定7种重金属铬、铜、砷、镉、铅、汞和钡含量,气相色谱质谱联用法测定44种农药残留量,并利用内梅罗综合污染指数法评价重金属污染情况。15批天麻样品中二氧化硫检出率100%,超标率100%,25批灵芝样品检出率12%,无超标现象。天麻和灵芝中重金属含量按中药材属性判定时,合格率100%,按食品属性参照国家安全食品标准判定时,15批天麻中Cr超标11批,25批灵芝样品中Pb超标1批,As超标2批,Cr超标14批;内梅罗综合污染指数显示,天麻和灵芝中轻度以上污染率为73%和40%。灵芝中共检出毒死蜱、联苯菊酯和百菌清3种农药,均符合相关限量要求,天麻样品未检出农药。天麻和灵芝均存在外源性污染风险,天麻中二氧化硫和重金属超标,灵芝有农药超标的风险,研究可为食药两用类物质开展安全性风险评估及制定限量标准提供参考和依据。

离子色谱法测定玫瑰花配方颗粒和月季花配方颗粒中的二氧化硫残留量

目的建立离子色谱法测定玫瑰花配方颗粒和月季花配方颗粒中二氧化硫的残留量。方法以DIONEX IonPac AS II-HC(4 mm×250 mm)为色谱柱,DIONEX IonPac AS II-HC(4 mm×50 mm)为保护柱;以20 mmol/L氢氧化钾溶液为淋洗液,等度淋洗,流速为1.0 ml/min;采用ASRS 3004-mm型连续自动再生阴离子抑制器,抑制模式为外加水自动再生抑制模式,抑制电流为50 mA;检测器为电导池检测器;柱温为30℃;进样量为100μl。结果硫酸根离子与其他成分的分离度良好,在0.0005~1.0μg范围内,浓度与峰面积间呈良好的线性关系,平均回收率为98.74%,RSD为1.57%。结论本方法简便、准确、灵敏度高、专属性强,可用于玫瑰花、月季花配方颗粒中二氧化硫残留量检测。

Effects of manganese dioxide additives on the electrical characteristics of Al-doped ZnO varistors

The effects of manganese dioxide (MnO 2 ) additives on the electrical characteristics of the Al-doped ZnO varistors are investigated. The leakage current densities of the samples decrease first and then increase again with the increase of the amount of MnO 2 additives. Correspondingly, the nonlinear coefficients of the samples keep on increasing and then decrease. In addition, the donor densities increase monotonously with the amount of the doped MnO 2 increasing. The effects of MnO 2 additives on the electrical characteristics of the samples are different from the conclusion of previous literatures. The reasons of the distinct effects are supposed to be related with the donor and interface state densities of the samples.