Structured hierarchical Mn–Co mixed oxides supported on silicalite-1 foam catalyst for catalytic combustion

Silicalite-1(S1)foam was functionalized by supporting manganese-cobalt(Mn-Co)mixed oxides to develop the structured hierarchical catalyst(Mn-Co@SlF)for catalytic combustion for the first time.The self-supporting S1 foam with hierarchical porosity was prepared via hydrothermal synthesis with polyurethane(PU)foam as the template.Subsequently,Mn-Co oxide nano sheets were uniformly grown on the surface of S1 foams under hydrothermal conditions to prepare the structured hierarchical catalyst with specific surface area of 354 m^2·g^-1,micropore volume of 0.141 cm^3·g^-1 and total pore volume of 0.217 cm3·g^-1,as well as a good capacity to adsorb toluene(1.7 mmol·g^-1 at p/p0=0.99).Comparative catalytic combustion of toluene of over developed structured catalyst Mn-Co@SlF was performed against the control catalysts of bulk Mn-Co@S1(i.e.,the crushed Mn-Co@SlF)and unsupported Mn-Co oxides(i.e.,Mn-Co).Mn-Co@SlF exhibited comparatively the best catalytic performance,that is,complete and stable toluene conversion at 2480 C over 65 h due to the synergy between Mn-Co oxides and S1 foam,which provided a large number of oxygen vacancies,high redox capacity.In addition,the hierarchical porous structure also improved the accessibility of active sites and facilitated the global mass transfer across the catalyst bed,being beneficial to the catalysis and catalyst longevity.

Additive manufacturing of sodalite monolith for continuous heavy metal removal from water sources

Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using clay as the base material;(ii)thermal activation of the 3D-printed clay monoliths by calcination(to produce reactive alumina and silica species and enable mechanical stabilization);(iii)conversion of the activated clay monoliths to hierarchical porous sodalite monoliths via hydrothermal alkaline treatment.Parametric studies on the effect of calcination temperature,alkaline concentration and hydrothermal treatment time on the property of the resulting materials(such as phase composition and morphology)at different stages of preparation was conducted.Under the optimal conditions(i.e.,calcination temperature of 850℃,NaOH concentration of 3.3 mol·L^(-1),reaction temperature of 150℃,and reaction time of 6 h),a high-quality pure sodalite monolith was obtained,which possesses a relatively high BET surface area(58 m^(2)·g^(-1))and hierarchically micro-meso-macroporous structure.In the proposed application of continuous removal of heavy metals(chromium ion as the model)from wastewater,the developed 3D-printed sodalite monolith showed excellent Cr^(3+)removal performance and fast kinetics(~98%removal efficiency within 25 cycles),which outperformed the packed bed using sodalite pellets(made by extrusion).

Haplotype variation and KASP markers for SiPSY1-A key gene controlling yellow kernel pigmentation in foxtail millet

Carotenoid biosynthesis and accumulation are important in determining nutritional and commercial value of crop products.Yellow pigmentation of mature kernels caused by carotenoids is considered a vital quality trait in foxtail millet,an ancient and widely cultivated cereal crop across the world.Genomic regions associated with yellow pigment content(YPC),lutein and zeaxanthin in foxtail millet grains were identified by genome-wide association analysis(GWAS),and SiPSY1(Phytoene synthase 1 which regulates formation of the 40-carbon backbone of carotenoids)was confirmed as the main contributor to all three components by knockout and overexpression analysis.SiPSY1 was expressed in seedlings,leaves,panicles,and mature seeds,and was subcellularly localized to chloroplasts.Transcription of SiPSY1 in 15 DAP immature grains was responsible for YPC in mature seeds.Selection of SiPSY1 combined with increased YPC in mature grains during domestication of foxtail millet was confirmed.Haplotype analysis suggested that expression level of SiPSY1 could be a selection target for future breeding programs,and a KASP marker was developed for selection of favorable SiPSY1 alleles in breeding.The results of this work will benefit nutritional and commercial improvement of foxtail millet varieties,as well as other cereal crops.

Analysis of Nitrogen Metabolism Related Enzymes and Related Physiological Indexes of Main Foxtail Millet Varieties Developed in North China

[Objectives] This study was conducted to clarify the evolution characteristics of foxtail millet varieties in different ages and provide a basis for the breeding of new varieties. [Methods] A field experiment was carried out on 20 main foxtail millet varieties promoted in North China developed from the 1980 s to 2000 s. The physiological and biochemical indexes of different foxtail millet varieties in four ages were compared, including chlorophyll content, soluble protein content, glutamine synthetase(GS) activity and glutamate synthase(GOGAT) activity, and the correlation between enzyme activity and yield was analyzed. [Results] The chlorophyll SPAD values of the flag leaf and functional leaves of foxtail millet varieties decreased with the filling process. The SPAD values of the flag leaf, top second leaf and top third leaf were higher in the varieties developed in the 1990 s and 2000 s than those in the 1980 s and 2010 s. The activity of glutamine synthetase(GS) and glutamate synthase(GOGAT) showed a single-peak curve in different foxtail millet varieties developed in the recent 30 years, and the peaks of the two were at 7 d and at 7 or 14 d, respectively. The activity of GS and GOGAT increased with the breeding age. In the period from 7 d after anthesis to the mature period, the decreases in the soluble protein content followed an order of 2010 s, 2000 s, 1990 s and 1980 s from small to large, indicating that the degradation rate of various enzyme sources and metabolic regulators in foxtail millet plants decreased during the improvement process. At 35 d after anthesis, the correlation coefficient between GS activity and yield was-0.247, that is, there was a negative correlation with yield. And there was a significant positive correlation between GOGAT activity and yield, and the correlation coefficient was as high as 0.455 at 7 d after anthesis. [Conclusions] Changes in the GS activity, GOGAT activity and soluble protein content in the flag leaf of foxtail millet varieties developed in recent years have a certain impact on yield.

Temporal variations and source apportionment of volatile organic compounds at an urban site in Shijiazhuang, China

Shijiazhuang,the city with the worst air quality in China,is suffering from severe ozone pollution in summer.As the key precursors of ozone generation,it is necessary to control the Volatile Organic Compounds(VOCs)pollution.To have a better understanding of the pollution status and source contribution,the concentrations of 117 ambient VOCs were analyzed from April to August 2018 in an urban site in Shijiazhuang.Results showed that the monthly average concentration of total VOCs was 66.27 ppbv,in which,the oxygenated VOCs(37.89%),alkanes(33.89%),and halogenated hydrocarbons(13.31%)were the main composite on.Eight major sources were identified using Positive Matrix Factorization modeling with an accurate VOCs emission inventory as inter-complementary methods revealed that the petrochemical industry(26.24%),other industrial sources(15.19%),and traffic source(12.24%)were the major sources for ambient VOCs in Shijiazhuang.The spatial distributions of major industrial activities emissions were identified by using geographic information statistics system,which illustrated the VOCs was mainly from the north and southeast of Shijiazhuang.The inverse trajectory analysis using Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)and Potential Source Contribution Function(PSCF)clearly demonstrated the features of pollutant transport to Shijiazhuang.These findings can provide references for local governments regarding control strategies to reduce VOCs emissions.

Using ultrasound to improve the sequential post-synthesis modification method for making mesoporous Y zeolites

Mesoporous Y zeolites were prepared by the sequential chemical dealumination(using chelating agents such as ethylenediaminetetraacetic acid,H EDTA,and citric acid aqueous solutions)and alkaline desilication(using sodium hydroxide,NaOH,aqueous solutions)treatments.Specifically,the ultrasound-assisted alkaline treatment(i.e.,ultrasonic treatment)was proposed as the alternative to conventional alkaline treatments which are performed under hydrothermal conditions.In comparison with the hydrothermal alkaline treatment,the ultrasonic treatment showed the comparatively enhanced efficiency(with the reduced treatment time,i.e.,5 min vs.30 min,all with 0.2 mol·L NaOH at 65°C)in treating the dealuminated Y zeolites for creating mesoporosity.For example,after the treatment of a dealuminated zeolite Y(using 0.1 mol·L H EDTA at 100°C for 6 h),the ultrasonic treatment produced the mesoporous zeolite Y with the specific external surface area()of 160 m·g and mesopore volume()of 0.22 cm·g,being slightly higher than that by the conventional method(i.e.,=128 m·g and=0.19 cm·g).The acidic property and catalytic activity(in catalytic cracking of-octane)of mesoporous Y zeolites obtained by the two methods were comparable.The ultrasonic desilication treatment was found to be generic,also being effective to treat the dealuminated Y zeolites by citric acid.Additionally,the first step of chemical dealumination treatment was crucial to enable the effective creation of mesopores in the parent Y zeolite(with a silicon-to-aluminium ratio,Si/Al=2.6)regardless of the subsequent alkaline desilication treatment(i.e.,ultrasonic or hydrothermal).Therefore,appropriate selection of the condition of the chemical dealumination treatment based on the property of parent zeolites,such as Si/Al ratio and crystallinity,is important for making mesoporous zeolites effectively.