Search

The sulfur biogeochemical cycle controls the sulfur dynamics in the soil. In contrast to almost all deposited sulfur leaching out in temperate catchments, approximately 80% of the deposited S is retained in the catchments in subtropical regions. However, the mechanisms for sulfur retention were unclear, hindering the understanding of potential threats of legacy sulfur with environmental changes. Here, we demonstrated that sulfate reduction (as sulfide fixed in soil) was a prominent yet overlooked mechanism for sulfur retention in addition to the widely recognized sulfate adsorption in soil, based on a study on soil sulfur storage and stable isotope signatures within entire soil profiles in a typical subtropical catchment in China. Using a dual‐isotopic model, the sulfate reduction flux was further determined to be 30% of the S deposition. Due to a lot of deposited sulfur fixed via sulfate reduction, the release of soil legacy sulfur would be less in response to decreasing sulfur deposition compared to the projections only considering adsorption. However, the remobilization of large amounts of reduced S should be regarded as a threat to the environment under climate change in the future. Plain Language Summary: Sulfur budget in catchments reveals substantial retention of around 80% of deposited sulfur in subtropical soils, mitigating acidification arising from heightened sulfur deposition. The substantial sulfur retention was previously ascribed to sulfate adsorption. However, our study unveils sulfate reduction as a prominent yet overlooked retention mechanism, evidenced by soil sulfur storage estimates and stable isotope signatures across complete soil profiles in a typical subtropical Chinese catchment. Sulfate adsorption displays reversibility with declining atmospheric deposition. However, sulfate reduction exhibits relatively stable except during periods of frequent drought attributed to climate change or the soil excavation induced by land‐use change. Key Points: A dual isotopic mass balance model was built to quantify the transformations of S in the ecosystemsSulfur retention accounted for approximately 80% of deposition based on the sulfur input–output budgets for 17 sites in subtropical ChinaSulfate reduction was a prominent mechanism for sulfur retention in addition to widely recognized sulfate adsorption [ABSTRACT FROM AUTHOR]

The problem of scale inhibition in thermal power plants using mine water as circulating cooling water is a major focus of current engineering attention. Mine water in North China is predominantly high sulfate mine water, with mine water in Shanxi mines generally having a sulfate content of over 1000 mg/L. Currently, most thermal power plants blindly follow the previous scale inhibitor with carbonate scale as the main scale inhibition target, which leads to a large amount of sulfate scale in its circulating cooling system, which is difficult to remove after the formation of sulfate scale. On the basis of the experiments, the corresponding scale inhibition laws were studied using the response surface method for the water quality characteristics of high sulfate mine water. The scaling process on the heat exchange surface of the circulating cooling water system was simulated by the hanging sheet deposition method, and the quantitative analysis was carried out by the weight method. Using EDTMPS as an example, the scale inhibition law of sulfate‐type scale inhibitors for this type of mine water was systematically investigated. The experiments showed that the scale inhibition rate (reduction of deposited scale after scale inhibitor dosing) reached a peak of 95.21% at a time of 6.1 h, a solution temperature of 70°C and an EDTMPS dosing rate of 6 mg/L. [ABSTRACT FROM AUTHOR]

The origins of atmospheric sulfate production have previously been explained by focusing on air quality models and complex chemical reaction processes. Here, we first report direct observations of sulfate production in stack plumes discharged from coal‐fired power plants, industrial boilers, and sintering plants equipped with wet desulfurization systems. Less than one third of the particulate SO42− in plumes is attributed to dust‐SO42− and SO3 measured in stacks. The SO2 aqueous‐phase oxidation process is critical in explaining the unknown sulfate formation in plume droplets with pH values ranging from 2.3 to 2.8. When the rapidly formed sulfate in wet plumes is included, a notable amount of underestimated sulfate (∼0.24 Tg in 2017) is emitted from industrial stacks in China and can partially explain the "missing sulfate" on driving most particle pollution episodes. Policy‐making targeting particulate emissions is suggested to substantially reduce sulfate emissions for further air quality improvement. Plain Language Summary: Sulfate aerosols are well known as an important atmospheric aerosol component, especially during haze periods. Their production pathway remains a mystery, and they are also referred to as missing sulfate. We show that sulfuric acid droplets are readily produced in wet plumes emitted from typical coal‐fired stationary sources. The freshly formed sulfate originates from the condensation and absorption of SO2 and SO3 emitted from stacks when the discharged flue gas cools in ambient air. We discover that the fast‐formed sulfate aerosols in the wet plumes from industrial stacks account for ∼31.4% of the directly emitted sulfate aerosols in China. This study advances our understanding of industrial particulate emissions and their contribution to atmospheric sulfate. Key Points: Acidic droplets with pH <3 formed in wet plumes are emitted from coal‐fired stationary sourcesThe SO42− concentrations in plumes grow explosively and are 2.8∼3.3 times higher than those in stacksSO2 aqueous‐phase oxidation process is critical in sulfate aerosol formation via plume droplets [ABSTRACT FROM AUTHOR]

The chemical and stable isotopic compositions (δ34SSO4 and δ18OSO4) of Xijiang River water in southwest China, were measured to determine the extent of rock weathering and associated CO2 consumption rates, and to assess the contamination sources of river water. The SO42− concentration in the river water was in the range of 0.05 to 0.96 mmol L−1 (mean value = 0.32 mmol L−1) and was characterized by δ34SSO4 values ranging from −9.1 to 5.1‰ (mean value = −2.1‰) and δ18OSO4 values ranging from −0.4 to 10.8‰ (mean value = 5.0‰). The δ34SSO4 and δ18OSO4 values ranged from high to low from the upper reaches to the lower reaches in all the river water samples. The results indicate that the oxidation of sulfide and anthropogenic inputs are the dominant processes affecting SO42− sources and S cycling of the Xijiang River during high‐discharge conditions, which are controlled by regional hydrological processes that are affected by natural processes and anthropogenic inputs Core Ideas: The dual isotopes (δ34SSO4 and δ18OSO4) of sulfate indicated S sources.The weathering rates of carbonate and silicate were calculated.The relative contributions of various sources are identified. [ABSTRACT FROM AUTHOR]

Sulfate geoengineering could mitigate global warming via injecting SO2 into the stratosphere. However, its impacts on regional climate might lead to adverse consequences for local agriculture. In this study, we simulated the impacts of sulfate geoengineering on rice yield in China both with sufficient irrigation (irrigated) and without irrigation (rainfed). We used Geoengineering Model Intercomparison Project G4 climates from six climate models to force the ORYZA version 3 crop model to simulate rice yields under sulfate geoengineering scenario. G4 prescribes a sulfate injection to offset the radiative forcing in the Representative Concentration Pathway (RCP) 4.5 scenario. Results indicated that during the last 15 years of G4 sulfate geoengineering (i.e., 2055–2069), the implementation of sulfate geoengineering increases rice yields in most areas in China comparing with that without the implementation of sulfate geoengineering (i.e., RCP4.5), with a yield increase of 5.3 ± 5.7% for irrigated yield and 4.8 ± 7.3% for rainfed yield. After the termination of sulfate geoengineering, the irrigated rice yield in G4 is still significantly higher than that in RCP4.5, but such increase is not significant for rainfed yield. Temperature is always the dominant factor that drives the rice yield change no matter under irrigated or rainfed conditions, but the effect from solar radiation cannot be ignored in southern China. Key Points: G4 sulfate geoengineering is projected to increase irrigated rice yield in China by 5.3 ± 5.7%G4 sulfate geoengineering is projected to increase rainfed rice yield in China by 4.8 ± 7.3%Temperature is the dominant factor driving the rice yield changes [ABSTRACT FROM AUTHOR]

The article reports on the geochemical attributes of trapped fluid inclusions in the gypsum of China's Lop Nor basin. It mentions the significance of the basin due to its source of sulphate-potash brines which are galuberite stratum. It also notes the presence of polyhalite, anhydrite and glauberite as revealed by petrographic research.

Reports that Emisal of Egypt and China National Technical Import and Export have signed an agreement to build a factory to produce magnesium sulphate for used in fertilizers and animal food.