Effects of sulfur dioxide on growth， gas exchange rate and leaf sulfur content of massion pine seedlings

The effects of sulfur dioxide(SO_2) on the dry weight growth gas exchange rate and leaf sulfur content of massion pine(Pinus massoniana Lamb. )were investigated. The results obtained in this study show that the dry weight growth and net photosynthetic rate of masson pine seedlings are reduced by exposure to SO_2 at ≥100 ppb. From these results,one of the main causes in the dieback of masson pine forest reported in Chongqing,China may be relatively high concentrations of atmospheric SO_2 in the relevant area.

Exploring the relationship between ambient sulfur dioxide and semen quality parameters:A systematic review and meta-analysis

Objective:To investigate the relationship between ambient sulfur dioxide(SO2)exposure and semen quality parameters.Methods:A systematic literature search was conducted to identify relevant studies investigating the association between SO2 exposure and semen quality parameters.This search encompassed the timeframe from January 2000 to May 2023 and included electronic databases such as Web of Science,Google Scholar,PubMed,Cochrane,and Scopus.Pooled effect estimates with 95%confidence intervals(CI)were calculated using percent changes(PC).The meta-analysis included seven studies with 6711 participants and 15087 semen samples.Results:The results revealed a significant negative association between ambient SO2 exposure and certain semen quality parameters.In particular,SO2 exposure was associated with a significant decrease in progressive motility(PC=0.032;95%CI:-0.063 to-0.001;P=0.044)and sperm concentration(PC=-0.020;95%CI:-0.036 to-0.005;P=0.012).However,no statistically significant associations were observed for total sperm count(PC=-0.038;95%CI:-0.079 to 0.003;P=0.070),seminal fluid volume(PC=-0.009;95%CI:-0.048 to-0.030;P=0.662)and sperm motility(PC=-0.17;95%CI:-0.363 to 0.022;P=0.830).In addition,the results of the subgroup analysis revealed specific variables that were associated with the decrease in relevant sperm parameters.Conclusions:This systematic review and meta-analysis provides compelling evidence supporting a consistent negative association between exposure to ambient SO2 and semen quality parameters.

Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

The reduction of phosphogypsum(PG)to lime slag and SO_(2)using coke can effectively alleviate the environmental problems caused by PG.However,the PG decomposition temperature remains high and the product yield remains poor.By adding additives,the decomposition temperature can be further reduced and PG decomposition rate and product yield can be improved.However,the use of current additives such as Fe_(2)O_(3)and SiO_(2)brings the problem of increasing economic cost.Therefore,it is proposed to use solid waste copper slag(CS)as a new additive to reduce PG to prepare SO2,which can reduce the cost and meet the environmental benefits at the same time.The effects of proportion,temperature and thermostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting conditions.Finally,the reaction mechanism is proposed.It is found that adding CS to the coke and PG system can increase the rate of PG decomposition and SO_(2)yield while lowering the PG decomposition temperature.For example,when the CS/PG mass ratio increases from 0 to 1,PG decomposition rate increases from 83.38%to 99.35%,SO_(2)yield increases from 78.62%to 96.81%,and PG decomposition temperature decreases from 992.4℃to 949.6℃.The optimal reaction parameters are CS/PG mass ratio of 1,Coke/PG mass ratio of 0.06 at 1100℃for 20 min with 99.35%PG decomposition rate and 96.81%SO_(2) yield.The process proceeds according to the following reactions:2CaSO_(4)+ 0.7C + 0.8Fe_(2)SiO_(4)→0.8Ca_(2)SiO_(4)+ 0.2Ca_(2)Fe_(2)O_(5)+ 0.4Fe_(3)O_(4)+2SO_(2)+ 0.7CO_(2)Finally,a process for decomposing PG with coke and CS is proposed.

Control strategy for sulfur dioxide and acid rain pollution in China

Several factors, namely, coal dominated primary energy mix, extensive economic development mode, inefficient energy utilization, and the imperfect environmental regulations, result in the serious urban sulfur dioxide pollution and large scale sulfate type acid precipitation in China. In 1995, China′s sulfur dioxide emissions reached 23.70 Mt, and the areas affected by acid rain accounted for 40% of the territory. Chinese government accords considerable importance to the sulfur dioxide and acid rain contamination. New sets of environmental friendly policies have been promulgated. But enforcement of laws and regulations on SO 2 emissions need to be further improved and broadened, especially those respond to market conditions. This paper focuses particular attention on the analysis of strategy, policies, and national actions which had or should be taken against sulfur dioxide emissions nationwide to achieve the environmental targets, on the basis of which gives the technical options in future.

Atmospheric Corrosion of Steel A3 Deposited with Ammonium Sulfate and in the Presence of Sulfur Dioxide

A laboratory study of the atmospheric corrosion of carbon steel deposited with (NH4)2SO4 in the presence of SO2 is reported. The different levels of (NH4)2SO4 (0, 15, 30, 45, 60 μg·cm-2) were added on the surface of the samples before the exposure. The corrosion was investigated by a combination of gravimetry, Fourier transform infrared spectroscope and scanning electron microscopy. A detailed knowledge about the corrosion products was acquired, both quantitatively and qualitatively. The results show that the metal loss increased and the increasing tendency of corrosion rates slowed down with the increasing exposure time. The phase constituents of the corrosion products are mainly α-FeO(OH), γ-FeO(OH), and δ-FeO(OH).

Photochemical reaction of magnesium tetraphenyl porphyrin with sulfur dioxide

The photochemical reaction of magnesium tetraphenyl porphyrin（MgTPP） with sulfur dioxide（SO_2） was investigated in dichloromethane（CH_2Cl_2） by steady-state fluorescence,UV-vis absorption,MS,and XRD spectroscopic techniques.These spectra showed that under irradiation MgTPP reacted with SO_2 to form 1：1 molecular adduct at first step.During the process of keeping irradiation and maintaining the flow of SO_2,SO_2 was reduced into S^（2-） by MgTPP and the results were detected using MS and XRD techniques.Understanding the photochemical reaction of MgTPP with SO_2 is of key interest in elucidating fundamental photochemical reaction mechanisms associated with this class of chlorophyll in the presence of SO_2.

Sulfur dioxide-hydrogen peroxide relationships and acidification of precipitation in Guiyang area-a case study

-The concentrations of gas phase SO2, O3 and chemical composition of sequential rainwater samples were measured on 6/11/88 to 6/28/88 at some sites of Guiyang area. S (IV) was present in great excess of H2O2 in rainwater samples collected at residential sites of the city corresponding to high level of gas phase SO2. Considerable H2O2 in rainwater samples was observed in background air at suburbs. The evidence that clean rainwater samples were collected at 20km away from the city in 6/18/88 precipitation event revealed that the major process of acidification of the rain in the high polluted areas was below-cloud scavenging of trace gases. From a simulation calculation it was found that the rate of oxidation of S(IV) by O3 and by Mn2+, Fe3+ catalytic in high pH rainwater is significant, but for low pH the major SO42- is produced by the reaction of S (IV) with H2O2.

Photocatalytic Reaction of Sulfur Dioxide with Heptane in the Gas-phase Over Titanium Dioxide

The photocatalytic reaction of sulfur dioxide with heptane was carried out with the aid of UV illuminated titanium dioxide ultrafine particles(UFP) at room temperature. The TiO 2 UFP was prepared by means of colloidal chemical method. The structure and the surface state of the as prepared TiO 2 UFP via different heat treatments were studied. As the calcining temperature decreased, the contents of hydroxyl on the surface increased, which could help to enhance the photocatalytic activity of the TiO 2 UFP. The mechanism of the photocatalytic reaction of sulfur dioxide with heptane was proposed, in which there was a competition of photocatalytic oxidation between sulfur dioxide and heptane over the TiO 2 UFP. It is inferred that the reactive oxygen species play an important role in the photocatalytic reaction of sulfur dioxide with heptane.

Theoretical Study of Small Water Clusters of Sulfur Dioxide

The intermolecular clusters of sulfur dioxide with water, SO2（H2O）n （n = 2～5）, are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets （6-311＋＋G（d,p） and aug-cc-pVDZ）. The equilibrium geometries, intermolecular binding energies, and anharmonic frequencies of the clusters are calculated and compared with those of pure water clusters and available experiments. SO2 tends to form cyclic hydrogen-bonded complexes with two or three water molecules. In the larger clusters, however, water molecules begin to retain the structure of pure water clusters and segregate from SO2. Infrared absorption assignments for the small clusters are discussed to resolve a possible incorrect assignment in a recent spectroscopic experiment on the clusters.

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

SELECTIVE SULFUR DIOXIDE DETERMINATION BY GAS DIFFUSION FLOW INJECTION ANALYSIS WITH CHEMILUMINESCENT DETECTION

Sulfur dioxide has been found to decrease the chemiluminescence of luminol-iodine system.A new determination method for sulfur dioxide in atmosphere is developed by applying this reaction to a flow injection gas diffusion separation system.This permits the determination of sulfur dioxide selectively and rapidly.

Numerical Simulation on the Rainout-Removal of Sulfur Dioxide and Acidification of Precipitation from Stratiform Clouds

The rainout-removal of SO2 and the acidification of precipitation from stratiform clouds are simulated using a one-dimensional, time-dependent model, parameterized microphysically in which dissolution and dissociation of gaseous SO2 and H2O2, and oxidation reaction in aqueous phase are taken into account. The effects of dynamic factors, including updraft flow and turbulent transport, and the concentration of gaseous SO2 and H2O2 being transported into the clouds on pH value of the precipitation, the conversion rate S(Ⅳ)-S(Ⅵ) and the wet deposition rate of SO2 are discussed.

Exposure Assessment of Ambient Sulfur Dioxide Downwind of an Oil Refinery in Curacao

Primary sources of atmospheric sulfur dioxide are anthropogenic activities associated with the burning of fossil fuels and industrial processes that may have associations with various morbidities and mortalities. As such, several regional and global regulatory agencies have recommended ambient air limits to reduce environmental exposures. The objectives of this study were to evaluate ambient levels of sulfur dioxide surrounding an oil refinery on the island of Cura?ao. Levels which were then compared to literature values and recommended public health guidelines to determine potential public health risks. Concentrations of sulfur dioxide in Curacao were found to be among the highest globally with an increasing trend over time. While the epidemiological evidence does not conclusively suggest there is a health risk from these levels of exposure, SO2 concentrations greatly exceed regulatory and guidance levels and suggest that further emissions control is warranted. Future recommendations include a more rigorous epidemiological study in Cura?ao and expand the air monitoring efforts to include areas upwind of the refinery as well as additional petrochemical emissions.

Power industry to reduce sulfur dioxide emissions

China has published a stricter emission standard for thermal power plants in order to help reduce the power industry's sulfur dioxide emissions by over six

Pd Pt VO_(x)/CeO_(2)-ZrO_(2):Highly efficient catalysts with good sulfur dioxide-poisoning reversibility for the oxidative removal of ethylbenzene

The PdPtVO_(x)/CeO_(2)-ZrO_(2)(PdPtVO_(x)/CZO)catalysts were obtained by using different approaches,and their physical and chemical properties were determined by various techniques.Catalytic activities of these materials in the presence of H_(2)O or SO_(2)were evaluated for the oxidation of ethylbenzene(EB).The PdPtVO_(x)/CZO sample exhibited high catalytic activity,good hydrothermal stability,and reversible sulfur dioxide-poisoning performance,over which the specific reaction rate at 160℃,turnover frequency at 160℃(TOF_(Pd or Pt)),and apparent activation energy were 72.6 mmol/(g_(Pt)·sec)or 124.2 mmol/(g_(Pd)·sec),14.2 sec^(-1)(TOF_(Pt))or 13.1 sec^(-1)(TOF_(Pd)),and 58 k J/mol,respectively.The large EB adsorption capacity,good reducibility,and strong acidity contributed to the good catalytic performance of PdPtVO_(x)/CZO.Catalytic activity of PdPtVO_(x)/CZO decreased when 50 ppm SO_(2)or(1.0 vol.%H_(2)O+50 ppm SO_(2))was added to the feedstock,but was gradually restored to its initial level after the SO_(2)was cut off.The good reversible sulfur dioxide-resistant performance of PdPtVO_(x)/CZO was associated with the facts:(i)the introduction of SO_(2)leads to an increase in surface acidity;(ii)V can adsorb and activate SO_(2),thus accelerating formation of the SO_(x)^(2-)(x=3 or 4)species at the V and CZO sites,weakening the adsorption of sulfur species at the PdPt active sites,and hence protecting the PdPt active sites to be not poisoned by SO_(2).EB oxidation over PdPtVO_(x)/CZO might take place via the route of EB→styrene→phenyl methyl ketone→benzaldehyde→benzoic acid→maleic anhydride→CO_(2)and H_(2)O.

The Formation of SO_(2) and Emission Reduction Solutions in the Preparation of a Hydrogenation Catalyst Support

The key reason for SO_(2) formation during the production of a residue hydrogenation catalyst support was identified and subsequent emission reduction solutions were then investigated and verified systematically.The results demonstrated that carbon-containing organic materials,including sesbania powder and cellulose,did not completely decompose over the temperature range of 350−600℃during the heating stage of the calcination process,but rather underwent a condensation reaction within the same temperature range to form carbon-containing species with a lower ratio of hydrogen to carbon and a higher condensation degree,which promoted the decomposition of sulfate to form SO_(2).Systematic experimental work revealed that three different measures,i.e.,applying the staged calcination method,reducing the heating rate,and increasing the air flow rate,during the calcination process could all achieve the effect of reducing SO_(2) emissions.

Correlation of Microbiological Stability with Redox Processes in White Wines

In this paper, the authors analyzed the correlation between the microbiological stability of white wines and the content of sulfur dioxide, which influences the main redox processes that take place in the technological stages of the wine. The consecutive, parallel and spontaneous development of several redox processes and their impact on the quality, microbiological and crystalline stability of white wines were examined. The reduction of additive and subtractive technological interventions, of the amounts of adjuvants (sulphurous anhydride) is essential for the production of organic wines.

Mechanism explanation for SO_2 oxidation rate of Cs-Rb-V series sulfuric acid catalyst at low temperature

The reaction kinetics of SO 2 oxidation on Cs Rb V series sulfuric acid catalyst promoted by alkali salts such as cesium and rubidium was studied. A three step reaction mechanism of SO 2 oxidation was proposed, in which it was assumed that oxidation of quadrivalent vanadium complex was a controlling step. Then, a mechanism model equation was concluded according to the three step reaction mechanism. The SO 2 oxidation rate was measured with a non gradient reactor under the conditions of temperature of 380～520?℃ and space velocity of 3?600～7?200?h -1 . Through calculating with Powell nonlinear regression method, the parameters of model equation were obtained: K 1=0.152?exp(-62?073/ (RT) ), K 2=8.18?exp(-2?384/ (RT) ), K 3=0.221?exp(-18?949/ (RT) ). It was found that the model equation could fit with all the experimental reaction rate data very well. [

Preparation of activated ceria and its desulfurization performance

Activated ceria （CeO2/γ-Al2O3） prepared by impregnation was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and hydrogen temperature-programmed reduction （TPR）. The desulfurization of the activated ceria was investigated by X-ray photoelectron spectroscopy （XPS）, Fourier transform infrared spectroscopy （FT-IR）, and thermogravimetric analysis （TG）. The results showed that ceria could be highly dispersed or crystallized on the surface of γ-alumina. The reduction temperatures of 0.1CeO2/γ-Al2O3, 0.45CeO2/7-A1203, and CeO2 ranged from 250℃ to 470℃, 330℃ to 550℃, and 350℃ to 550℃, respectively. The reduction peak temperature of 0.45CeO2/γ-Al2O3 was higher than that of 0.1CeO2/γ-Al2O3, which was consistent with the reduction temperature of CeO2. 02 participated in the reaction between ceria and sulfur dioxide. The desulfurization product was cerium（III） sulfate. The intensity of the hydroxyl band decreased with the formation of sulfate species.