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Zeolite addition has been widely suggested for its ability to overcome ammonia stress occurring during anaerobic digestion. However little is known regarding the underlying mechanisms of mitigation and especially how zeolite influences the microbial structuration. The aim of this study was to bring new contributions on the effect of zeolite on the microbial community arrangement under a low ammonia stress. Replicated batch experiments were conducted. The microbial population was characterised with 16S sequencing. Methanogenic pathways were identified with methane isotopic fractionation. In presence of ammonia, zeolite mitigated the decrease of biogas production rate. Zeolite induced the development of Izimaplasmatales order and preserved Peptococcaceae family members, known as propionate degraders. Moreover methane isotopic fractionation showed that hydrogenotrophic methanogenesis was maintained in presence of zeolite under ammonia low stress. Our results put forward the benefit of zeolite to improve the bacteria-archaea syntrophy needed for propionate degradation and methane production under a low ammonia stress.Cr(VI) compounds at high temperature usually tend to decompose and reduce into Cr(III) due to thermodynamically instability for Cr(VI). This study found Cr(VI) could be reduced into Cr(V) instead of Cr(III) in the presence of CaO during heating solid waste containing Cr(VI). CaCrO4 is prepared and mixed with CaO as simulated solid waste containing Cr(VI). It was found that CaCrO4 reacted with CaO and formed a new product Ca5(CrO4)3O0.5 at temperature range of 800 and 1000 °C. The valence state of Cr in Ca5(CrO4)3O0.5 is determined to be +5 b y XPS analysis, and the color for new formed Cr(V) is observed in green, similar to Cr(III) compounds. The temperature and CaO are two keys to arouse the reduction reaction of Cr(VI) into Cr(V). In particular, the reduction of Cr(VI) into Cr(V) is strongly depended on temperature (800-1000 °C), this reaction can be balanced within 10 min, while prolonging sintering time has little help for promoting the reduction of Cr(VI) to Cr(V). Additionally, it was found Cr(V) can keep stable and not be re-oxidized into Cr(VI) at 800-1000 °C. Above results offers some new understanding and knowledge about the formation of Cr(V) in presence of much CaO or CaCO3 during heating solid waste containing Cr(VI).In this work, Lysinibacillus sp. JLT12 was used to remove the Cr(VI)-induced passive layer on the magnetite. Mechanism study via dynamic kinetics, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy analyses revealed that Lysinibacillus sp. JLT12 could remove the passive layer (lepidocrocite and goethite) to facilitate the further Cr(VI) reduction by magnetite. For large-scale applications, porous ceramsite (PC) was prepared with magnetite, kaolin, and fallen leaves. Lysinibacillus sp. was then immobilized on the holes in PC. Slow-released nutrients were added to immobilized porous ceramsite (IM-PC) at a ratio of 1.510 (g/g) to supply carbon, nitrogen, and phosphorus to Lysinibacillus sp. JLT12 with low secondary pollution. The performance of IM-PC was evaluated via a column experiment. The results indicate that, in the presence of Lysinibacillus, the break-through time and maximum adsorption ability of IM-PC were 11.67 h and 121.47 mg/g, respectively. These values are higher than those of PC. Additionally, break-through curves detected at 5, 10, and 15 days demonstrated that the usage life of IM-PC was significantly longer than that of PC.Catalytic oxidation is a promising technique to control the emission of gaseous pollutants. Three-dimensionally ordered macroporous (3DOM)-based catalysts have aroused widespread attention because of their high porosity, large surface area and pore volume, superb ability of mass transfer. Therefore, they have been widely used in gaseous pollutants control field, such as soot and methane catalytic combustion, VOCs catalytic oxidation, photocatalytic CO2 reduction and so on. In this review, the recent studies about the preparation and applications of 3DOM catalysts are summarized. At the same time, the advantages and mechanism of the 3DOM catalysts used in gaseous pollutants control are introduced in depth. Finally, the perspective and future direction of 3DOM-based catalysts for gaseous pollutants control are proposed.In recent years, research on graphene oxide (GO) has developed rapidly in both academic and industrial applications such as electronic, biosensor, drug delivery, water treatment and so forth. Based on the large amount of applications, it is anticipated that GO will inevitably find its own way to the environment, if used are not restricted to prevent their release. Environmental transformation is an important transformation process in the natural environment. In this review, we will summarize the recent developments on environmental transformation of GO in the aquatic environment. Although papers on environmental transformation of graphene-based nanomaterials can be found, a systematic picture describing photo-transformation of GO (dividing into different irradiation sources), environmental transformation of GO in the dark environmental, the environmental toxicity of GO are still lacking. Thus, it is essential to summarize how different light sources will affect the GO structure and reactive oxygen species generation in the photo-transformation process, how GO will react with various natural constituents in the aquatic environment, whether GO will toxic to different aquatic organisms and what will be the interactions between GO and the intracellular receptors in the intracellular level once GO released into the aquatic environment. This review will arouse the realization of potential risk that GO can bring to the aquatic environment and enlighten us to pay attention to behaviors of other two-dimensional GO-like nanomaterials, which have been intensively applied and studied in recent years.Polyacrylonitrile fiber was successfully modified with triazine-based dendrimer via grafting method as a promising adsorbent for removal of mercury species from aqueous media. The prepared adsorbent was characterized by elemental analysis, scanning electron microscope, Fourier transform infrared spectroscopy, porous structure analysis and X-ray photoelectron spectroscopy, providing the evidence of successful fabrication. The adsorption conditions were found via varying pH, dosage, coexisting substances, contact time, temperature and concentration. Adsorption performance, described better by the pseudo-second-order kinetics with intraparticle diffusion as rate controlling step and Langmuir isotherm model, indicated a chemisorption process with the maximum Langmuir adsorption amount of 227.64 mg g-1 for mercury ions. Thermodynamically, adsorption of mercury ions was spontaneous and endothermic. Desorption and regeneration experiments demonstrated that it could be reused in five successive adsorption cycles without significant loss of its original performance. Experimental data and density functional theory calculation disclosed the coordination geometries and chelating mechanism between the adsorbent and mercury ions. https://www.selleckchem.com/products/oxalacetic-acid.html The proposed study would provide a new prospect for the purification of mercury in aqueous system by functionalizing commercial polyacrylonitrile fiber with dendrimers.Tebuconazole is a triazole fungicide, used in agriculture to treat phytopathogenic fungi, and as a biocide, has been reported to be related to reproductive and developmental toxicity. The purpose of this study was to investigate the effect of tebuconazole exposure on rat fetal Leydig cells and fetal testis during pregnancy. Pregnant Sprague-Dawley rats were randomly divided into 4 groups, daily gavaged with corn oil (as a control), 25, 50, and 100 mg/kg body weight tebuconazole for 10 days (from the 12th day of pregnancy). Tebuconazole increased fetal serum testosterone and progesterone levels at a dose of 100 mg/kg. Exposure to 100 mg/kg tebuconazole significantly caused an increase in the number of fetal Leydig cells per testis without inducing cell aggregation. Tebuconazole up-regulated the expression of Star, Cyp11a1, Hsd17b3, and Fshr and their proteins. Further investigation found that tebuconazole caused increased phosphorylation of AKT1, ERK1/2, and mTOR, the level of BCL2, as well as the decrease of Beclin1, LC3B, and BAX, which may contribute to the fetal Leydig cell autophagy and proliferation. In conclusion, in utero exposure of tebuconazole causes the proliferation of fetal Leydig cells.Beans of cacao (Theobroma cacaoL.) are used to produce a variety of chocolate products. Bioaccumulation of metals at toxic levels through the consumption of contaminated products has been identified as a health concern in humans. Both metal diversity and concentration as well as their interactions in the soil influence essential and non-essential metal uptake in plants; but the effects of these on bioaccumulation of metals in cacao is not understood across diverse soil types. In this study eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were investigated in 12 soil subgroups belonging to four soil orders across 15 locations in Trinidad, with the aim to investigate the effect of soil metal diversity and concentration on metal bioaccumulation in cacao. Soil metals were extracted using five methods (aqua regia, DTPA, Mehlich 3, nitric acid, and water). Cacao leaf metal concentrations were determined using the USEPA 3052 method. Metal extraction efficiency ranged between methods with aqua regia ≥ nitric acid > Mehlich 3 ≥ DTPA ≥ water across all metals. The soil extraction method that best predicted cacao leaf metal concentrations varied with the metal - Mehlich 3 or DTPA for Cd, Ni, Zn; aqua regia, Mehlich 3, or nitric acid for Pb, and water for Mn. A stepwise regression analysis showed that plant metal concentration can be predicted using soil physicochemical characteristics as well as the concentration of metals in the soil. The importance of soil type on cacao leaf metal bioaccumulation is discussed.Nitrate (NO3-), sulfate (SO42-) and ammonium (NH4+) in airborne fine particles (PM2.5) play a vital role in the formation of heavy air pollution in northern China. In particular, the increasing contribution of NO3- to PM2.5 has attracted worldwide attention. In this study, a highly time-resolved analyzer was used to measure water-soluble inorganic ions in PM2.5 in one of the fastest-developing megacities, Tianjin, China, from November 15 to March 15 (wintertime heating period) in 2014-2019. Severe PM2.5 pollution episodes markedly decreased during the heating period from 2014 to 2019. The highest concentrations of NO3- and SO42- were recorded in the heating period of 2015/2016. Afterwards, NO3- decreased from 2015/2016 (20.2 ± 23.8 μg/m3) to 2017/2018 (11.6 ± 14.8 μg/m3) but increased with increasing NOx concentrations during the heating period of 2018/2019. A continuous decrease in the SO2 concentration led to a decrease in SO42- from 2015/2016 (16.8 ± 21.8 μg/m3) to 2018/2019 (6.5 ± 8.9 μg/m3). The NO3- andt spots of NO3-, SO42- and NH4+ (higher concentrations) in the wind sectors between NE and SE at wind speeds of approximately 6-21 km/h. The southern areas in the North China Plain and parts of the western areas of China contributed more NO3-, SO42- and NH4+ than other areas to the study site. The abovementioned areas were also characterized by a higher contribution of NO3- than of SO42- to the study site and by NH4+-rich conditions. In summary, more efforts should be made to reduce NOx in the Beijing-Tianjin-Hebei region. This study provides observational evidence of the increasingly important role of nitrate as well as scientific support for formulating effective control strategies for regional haze in China.
Read More: https://www.selleckchem.com/products/oxalacetic-acid.html
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