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Qiongli Zhao, Linning Ren, Jiao Hou, Wenquan Yu, Junbiao Chang
A novel annulation reaction of N-(het)aroyldiazenes and isothiocyanates has been established. This transformation involves a sequential cyclization and desulfurization/intramolecular rearrangement to produce 2-imino-1,3,4-oxadiazolines. The less-stable N-(het)aroyldiazenes can be conveniently generated in situ by I2 -mediated oxidation of hydrazides, which allows a one-pot synthesis of the products directly from readily accessible hydrazide and isothiocyanate substrates. This operationally simple synthetic process requires no use of malodorous isocyanides and can be conveniently conducted on a gram scale...
December 14, 2018: Organic Letters
Shaorui Zhang, Xiaoqing Lin, Zhiliang Chen, Xiaodong Li, Xuguang Jiang, Jianhua Yan
Co-combustion experiments of municipal solid waste and coal were carried out in a drop tube furnace at high temperature 1300 °C. The effect of different simulated municipal solid waste (SMSW) added proportion (0, 7.5, 15, 20 and 25 wt%) in the blend fuels on the characteristics of gaseous pollutants emissions, e.g. CO, HCl, SO2 , NOx , and heavy metals, and fly ash were studied. The results indicated that CO and CH4 emission concentrations were at a low level under all conditions. With the increasing proportion of SMSW, the combustion efficiency decreased slightly, the HCl emission increased obviously at 25% conditions while at lower proportion conditions the change was not significant; the NOx emission concentration showed a tendency to rise first and then decrease, while the SO2 showed an exactly opposite trend; besides, Fe, Cl and S content in the fly ash increased obviously...
November 2018: Waste Management
Hafiz M A Sharif, Hao-Yi Cheng, Muhammad Rizwan Haider, Kifayatullah Khan, Lihui Yang, Aijie Wang
Dealing with nitrogen oxides (NOx) from flue gas is commonly to form harmless nitrogen gas (N2) in traditional technologies, while less effort has been done to recover these N containing chemicals. In this work, we developed a novel nano-magnetic adsorbent, Fe3O4@EDTA@Fe(II) complex (MEFe(II)), for NO removal. The NO adsorbed by MEFe(II) was then selectively converted to N2O, a valuable compound in many industries, by using sulfite (a product from desulfurization in flue gas treatment) as the reductant with the regeneration of MEFe(II)...
December 10, 2018: Environmental Science & Technology
Nishant S More, Parag R Gogate
Intensified desulfurization of simulated crude fuel containing thiophene has been investigated using ultrasonic flow cell in combination with oxidizing agents such as peracetic acid, hydrogen peroxide (H2 O2 ) and Fenton reagent at ambient conditions. The effect of thiophene loading, recirculation flow rate and the oxidant loading on the extent of desulfurization has been studied at 1 L capacity. Combination of ultrasound and hydrogen peroxide at optimized loading of 8% resulted in higher extent of desulfurization (38%) as compared to only ultrasound (17%)...
March 2019: Ultrasonics Sonochemistry
Kelly D Good, Jeanne M Vanbriesen
Wet flue gas desulfurization (FGD) wastewater discharges from coal-fired power plants may increase bromide concentrations at downstream drinking water intakes, leading to increased formation of toxic disinfection byproducts (DBPs). Despite this, bromide was not regulated in FGD wastewater in the 2015 Steam Electric Effluent Limitations Guidelines and Standards (ELGs). Case-by-case management was recommended instead, depending on downstream drinking water effects. The present work seeks to identify U.S. regions where power plant discharges could affect drinking water...
December 4, 2018: Environmental Science & Technology
Yishan Guo, Zhewei Xu, Chenghang Zheng, Jian Shu, Hong Dong, Yongxin Zhang, Weiguo Weng, Xiang Gao
Sulfur dioxide (SO2 ) is one of the main air pollutants from many industries. Most coal-fired power plants in China use wet flue gas desulfurization (WFGD) as main method for SO2 removal. Presently, the operating of WFGD lacks accurate modeling method to predict outlet concentration, let alone optimization method. As a result, operating parameters and running status of WFGD are adjusted based on the experience of the experts, which brings about the possibility of material waste and excessive emissions. In this paper, a novel WFGD model combining a mathematical model and an artificial neural network was developed to forecast SO2 emissions...
November 30, 2018: Journal of the Air & Waste Management Association
Carmela Conidi, Francesca Macedonio, Aamer Ali, Alfredo Cassano, Alessandra Criscuoli, Pietro Argurio, Enrico Drioli
An integrated membrane process for the treatment of wastewaters from a flue gas desulfurization (FGD) plant was implemented on a laboratory scale to reduce their salt content and to produce a water stream to be recycled in the power industry. The process is based on a preliminary pretreatment of FGD wastewaters, which includes chemical softening and ultrafiltration (UF) to remove Ca2+ and Mg2+ ions as well as organic compounds. The pretreated wastewaters were submitted to a reverse osmosis (RO) step to separate salts from water...
November 26, 2018: Membranes
Benjamin R Lundgren, Zaara Sarwar, Kyle S Feldman, Joseph M Shoytush, Christopher T Nomura
Dimethylsulfide (DMS) is a volatile sulfur compound produced mainly from the degradation of dimethylsulfoniopropionate (DMSP) in marine environments. DMS undergoes oxidation to form dimethylsulfoxide (DMSO), dimethylsulfone (DMSO2 ) and methanesulfonate (MSA), all of which occur in terrestrial environments and are accessible for consumption by various microorganisms. The purpose of the current study was to determine how the enhancer-binding proteins SfnR1 and SfnR2 contribute to the utilization of DMS and its derivatives in Pseudomonas aeruginosa PAO1...
November 26, 2018: Journal of Bacteriology
Masoud Rahimi, Shahrokh Shahhosseini, Salman Movahedirad
Ultrasound assisted oxidative desulfurization (UAOD) is a promising technology, which can result in ultra-low sulfur fuels in order to reduce the environmental crisis. Most of the researches have been conducted with the experimental approaches. In the present study, a computational fluid dynamic (CFD) model has been developed to investigate the hydrodynamics as well as the reactions involved in a sonoreactor. The results indicate that the physical and chemical effects associated with the ultrasonic field can contribute to the enhancement of the reaction and sulfur removal rates...
November 9, 2018: Ultrasonics Sonochemistry
Xiaoce Tian, Zhen Zhou, Yi Xin, Lu-Man Jiang, Xiaodan Zhao, Ying An
A novel sulfate removal process via ettringite precipitation was developed by dissolving ettringite and recycling Al3+ under low pH condition. Effects of solid to liquid ratios, pH and temperature on ettringite dissolution, Al recovery and transformation of precipitates were investigated by batch experiments. The optimum condition for Al recovery is pH =3.0, suspended solid of 9.8 g/L and temperature below 303 K. Ettringite dissolution consists of two stages, (i) rapid but inconsistent dissolution with the fastest release of sulfate, followed by calcium, and then Al(OH)6 3- ; (ii) slow dissolution of Al(OH)6 3- core and gypsum precipitation...
November 14, 2018: Journal of Hazardous Materials
Jie Liu, Su Lu, Lidong Wang, Tieyue Qi, Dan Qi, Xinyu Xing, Yaoyu Zhang, Huining Xiao, Shihan Zhang
Oxidation of magnesium sulfite (MgSO3 ) is a crucial step for reclaiming the product in wet magnesia desulfurization processes. Here, for enhancing this reaction, a bimetallic catalyst was developed by loading CoOx and MnOx species on a biomass-derived active carbon (AC) support to minimize the costs and potential environmental risks during catalyst application. The substitution effect of Mn to Co sites was investigated, and a comparison of the catalyst with plain cobalt suggested that the ratio of Co/Mn must be greater than 3...
November 13, 2018: Journal of Hazardous Materials
Shanshan Su, Yuyang Liu, Xuemin Liu, Wei Jin, Yaping Zhao
To enhance the catalytic and separation properties of akaganéite nanoparticles, rice spike-like akaganéite impregnated graphene oxide (β-FeOOH@GO) nanocomposite was fabricated through facile hydrolysis. The apparent first-order decolorization rate of methylene blue (MB) in β-FeOOH@GO catalyzed photo Fenton-like system was 0.6322 min-1 about 3 folds that of prinstine β-FeOOH nanoparticles. The degradation intermediates of MB adsorbed on the solid surface of β-FeOOH@GO were comprehensively identified with time of flight-secondary ion mass spectroscopy (TOF-SIMS) for the first time...
November 16, 2018: Chemosphere
Osmair Vital de Oliveira, Gabriela de Carvalho Costa, Luciano T Costa
Benzothiophene (BT) and dibenzothiophene (DT) are the most important contaminants in the petroleum derivatives responsible for serious environmental and health problems. Therefore, we have investigated the absorption of these compounds by the first time considering cucurbit[7]uril (CB[7]) as the host molecule and using DFT//B3LYP-D3/6-31G(d) level of theory. The BT and DT absorbed into CB[7] do not undergo a significant structural change in the CB[7] structure. The energy gap of the S-compounds@CB[7] in water and hexane solvents was approximately of 5 eV, and this large value implies that the complexes have high chemical stability...
November 19, 2018: Journal of Physical Chemistry. B
Chinna Ayya Swamy P, Jeyabalan Shanmugapriya, Subramanian Singaravadivel, Gandhi Sivaraman, Duraisamy Chellappa
Three π-extended anthracene-bearing thioacetals ( 1-3 ) have been synthesized, and their fluorescence " turn-on " responses to Hg2+ ions are studied. The chemodosimetric fluorescence-sensing behavior and their resulting hydrolysis via a desulfurization reaction mechanism leads to the formation of highly fluorescent respective aldehyde substitutions. Furthermore, this mechanism was supported by increase in the quantum yields of their resulting aldehydes and is correlated to their molecular substitution...
October 31, 2018: ACS Omega
Jing Liu, Xiao-Min Li, Jing He, Lu-Ying Wang, Jian-Du Lei
A core-shell Cu-benzene-1,3,5-tricarboxylic acid (Cu-BTC)@TiO₂ was successfully synthesized for photocatalysis-assisted adsorptive desulfurization to improve adsorptive desulfurization (ADS) performance. Under ultraviolet (UV) light irradiation, the TiO₂ shell on the surface of Cu-BTC achieved photocatalytic oxidation of thiophenic S-compounds, and the Cu-BTC core adsorbed the oxidation products (sulfoxides and sulfones). The photocatalyst and adsorbent were combined using a distinct core-shell structure...
November 7, 2018: Materials
Harald John, Markus Siegert, Andreas Kranawetvogl, Horst Thiermann
RATIONALE: Dimethoate (DIM, S=P (OMe)2 -S-CH2 -C(O)-NH-CH3 ) is a dimethyl phosphorodithioate pesticide widely used in agri- and horticulture that undergoes biotransformation in vivo by desulfuration into its more toxic oxono-derivative omethoate (OM, O=P (OMe)2 -S-CH2 -C(O)-NH-CH3 ). OM inhibits acetylcholinesterase thus provoking cholinergic crisis in vivo, ultimately leading to death. Quantitative approaches for the determination of DIM and OM in environmental and toxicological samples make use of tandem mass spectrometry (MS2 )...
November 7, 2018: Rapid Communications in Mass Spectrometry: RCM
Songtao Liu, Jianmeng Chen, Yue Cao, Haikuan Yang, Chuanmin Chen, Wenbo Jia
Method 30B and the Ontario Hydro Method (OHM) were used to sample the mercury in the flue gas discharged from the seven power plants in Guizhou Province, southwest China. In order to investigate the mercury migration and transformation during coal combustion and pollution control process, the contents of mercury in coal samples, bottom ash, fly ash, and gypsum were measured. The mercury in the flue gas released into the atmosphere mainly existed in the form of Hg°. The precipitator shows a superior ability to remove Hgp (particulate mercury) from flue gas...
November 5, 2018: Journal of the Air & Waste Management Association
Che-Jung Hsu, Hsin-Jin Chiou, Yun-Hsin Chen, Kuen-Song Lin, Mark J Rood, Hsing-Cheng Hsi
A series of batch experiments were conducted to obtain the optimal adsorption condition for removing aqueous Hg from actual lime-based wet flue gas desulfurization (WFGD) wastewater with sulfur-containing activated carbon (SAC). The experimental results showed that SAC1 had an average 0.32 μg mg-1 larger aqueous Hg adsorption capacity and 21% larger Hg removal than the CS2 -treated SAC1 (i.e., SAC2) in all tested pH values, confirming that greater sulfur content associated with effective sulfur functional group (i...
October 19, 2018: Environmental Research
In-Hwan Lee, Emre H Discekici, Shelby L Shankel, Athina Anastasaki, Javier Read de Alaniz, Craig J Hawker, David J Lunn
We report a simple and efficient transformation of thiol and thiocarbonylthio functional groups to bromides using stable and commercially available brominating reagents. This procedure allows for the quantitative conversion of a range of small molecule thiols (including primary, secondary and tertiary) to the corresponding bromides under mild conditions, as well as the facile chain-end modification of polystyrene (PS) homopolymers and block copolymers prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization...
December 14, 2017: Polymer Chemistry
Alexánder Garay Talero, Bruna Simões Martins, Antonio C B Burtoloso
A general, mild, and versatile synthesis of the challenging α-aryl-β-ketosulfoxonium ylides has been developed for the first time, substituting traditional methods starting from diazo compounds. The arylation of easily accessible β-ketosulfoxonium ylides using aryne chemistry allowed the preparation of a large scope of the pro-chiral ylides in very good yields (40 examples; up to 85%). As applications, these ylides were smoothly converted into α-aryl ketones after desulfurization in good yields (up to 98%) as well as in other important derivatives...
October 26, 2018: Organic Letters
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