Reaction characteristics investigation of CeO_(2)-enhanced CaSO_(4) oxygen carrier with lignite

Calcium sulfate(CaSO_(4))has been verified as a promising oxygen carrier(OC)in the chemical looping combustion(CLC)for its high oxygen capacity,abundant reserve and low cost,but its low reactivity and deleterious sulfur species emission from the side reactions of CaSO_(4) should be well considered for its wide application in CLC.In order to promote the reactivity of CaSO_(4) and increase its potential to inhibit the gaseous sulfur emission,a CeO_(2)-enhanced CaSO_(4) OC mixed OC of core–shell structure was prepared using the combined template synthesis method.Reaction characteristics of the prepared CaSO_(4)-CeO_(2) mixed OC with a typical lignite was first conducted and systematically investigated,and an improved reactivity of the prepared CaSO_(4)-CeO_(2) mixed OC was demonstrated than its single component CaSO_(4) or CeO_(2) due to the fast transfer and exchange of oxygen from the CaSO_(4) substrate to coal via the doped CeO_(2).Furthermore,the solid products formed from the mixed CaSO_(4)-CeO_(2) OC with the selected coal were collected and analyzed.Especially,evolution and redistribution of the sulfur species of different forms were focused.At the latter reaction stage of YN reaction with the CaSO_(4)-CeO_(2) mixed OC,the SO_(2) emitted from the side reactions of CaSO_(4) was greatly diminished and the doped CeO_(2) was proven effective to directionally fix the SO_(2) released to turn into different solid sulfur compounds,which were determined as Ce_(2)O_(2)S,Ce_(2)S_(3) and Ce_(2)(SO_(4))_(3)·5H_(2)O and formed through the different pathways.In addition,good regeneration of the reduced CaSO_(4)-CeO_(2) mixed OC could be reached in spite of the unavoidable interaction between the included minerals in coal and the reduced mixed OC.Overall,the combined template method-made CaSO_(4)-CeO_(2) mixed OC reported herein was not only endowed with enhanced reactivity for coal conversion,but also owned the potential to directionally fix the gaseous sulfur emission,which is quite applicable as OC for simultaneous decarbonatization and desulfurization in the real CLC process.

PRECISE MOMENT ASYMPTOTICS FOR THE STOCHASTIC HEAT EQUATION OF A TIME-DERIVATIVE GAUSSIAN NOISE

This article establishes the precise asymptotics Eu^m(t, x)(t → ∞ or m → ∞) for the stochastic heat equation ?u/?t(t, x) =1/2?u(t, x) + u(t, x)(t, x)?W/?t(t, x) with the time-derivative Gaussian noise W?/?t(t, x) that is fractional in time and homogeneous in space.

Visible light assisted enzyme-photocatalytic cascade degradation of organophosphorus pesticides

The worldwide application of organophosphorus pesticides(OPs)has promoted agricultural development,but their gradual accumulation in soil and water can seriously affect the central nervous system of humans and other mammals.Organophosphorus hydrolase(OPH)is an effective enzyme that can catalyze the degradation of the residual OPs.However,the degradation products such as p-nitrophenol(p-NP)is still toxic.Thus,it is of great significance to develop a multi-functional support that can be simultaneously used for the immobilization of OPH and the further degradation of p-NP.Herein,a visible light assisted enzyme-photocatalytic integrated catalyst was constructed by immobilizing OPH on hollow structured Au-TiO_(2)(named OPH@H-Au-TiO_(2))for the degradation of OPs.The obtained OPH@H-Au-TiO_(2)can degrade methyl parathion to p-NP by OPH and then degrade p-NP to hydroquinone with low toxicity by using H-Au-TiO_(2)under visible light.OPH molecules were immobilized on HAu-TiO_(2)through adsorption method to prepare OPH@H-Au-TiO_(2).After 2.5 h of reaction,methyl parathion is completely degraded,and about 82.64%of the generated p-NP is further degraded into hydroquinone.After reused for 4 times,the OPH@H-Au-TiO_(2)retains more than 80%of the initial degradation activity.This research presents a new insight in designing and constructing multi-functional biocatalyst,which greatly expands the application scenarios and industrial value of enzyme catalysis.

Particles attrition of binary mixtures in the coal-fueled chemical looping system based on fluidized bed

In this work,a reactive air jet attrition device with auto-recording and collection of elutriated fines was developed.Results established insights into the physiochemical interaction and further correlated attrition behaviors between char and oxygen carriers under various operation modes.The attrition rate increased by over 110% upon the introduced CO_(2),which brought in the significant effect of thermo-chemical stress,similarly in effects of the increased char addition ratio and the decreased sizes of char or hematite in different extents.For the char-hematite co-attrition process,the elutriated carbon loss of char with poor mechanical strength was found to be over 10%,while the reactive iron loss of hematite was found to be 6.3%,and was enriched in elutriated fines.The reaction-derived thermochemical stress and the collision-derived mechanical stress jointly controls the particle attrition during the cyclic transformation of oxygen carrier particles in coal-fueled chemical looping fluidization,especially sig-nificant in its reduction stage.

STING,a critical contributor to SARS-CoV-2 immunopathology

Recently,a study published in Nature by Domizio et al.1 revealed the underlying mechanism of aberrant immunopathology during the late phase of infection with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The authors provided evidence demonstrating that stimulator of interferon genes(STING)plays a unique role in the alveolus-capillary cytokine storm induced by mitochondrial DNA(mtDNA)during coronavirus disease 2019(COVID-19)(Fig.1).Some studies stressed that the STING agonists block the SARS-CoV-2 infection via triggering the type I interferons(IFNs)response,2,3 while others revealed that SARS-CoV-2 induces the chromatin DNA traveling to cytosol by promoting the cell-tocell fusion,resulting in the activation of cGAS-STING signaling.

ADP-riboxanation:a new pyroptosis evasion strategy

A recent study published in Nature by Li et al.(2021)revealed the underlying mechanism by which Shigella flexneri evades host pyroptosis using a type III secretion system(T3SS)effector,OspC3.OspC3 suppresses the proteolytic activity of caspase-11 or caspase-4(hereafter referred to as‘caspase-11/4’)in a nicotinamide adenine dinucleotide(NAD+)-dependent manner by catalyzing adenosine diphosphate riboxanation(ADP-riboxanation)on arginine 314(Arg314)and Arg310 in caspase-4 and caspase-11,respectively(Figure 1).In addition,S.flexneriΔicsAΔospC3 is a live-attenuated vaccine candidate.