Application of response surface methodology in optimizaing thesulfation-roasting-leaching process of nickel laterite

Nickel was recovered from nickel laterite using a sulfation-roasting-leaching process and the effects of operation parameters in- cluding acid addition, roasting temperature, and roasting time on nickel extraction and iron dissolution were investigated using response sur- face methodology （RSM）. Two second-order polynomial models of high significance were presented to show the relationship between the responses and the variables. The analysis of variance （ANOVA） showed high coefficients of determination （R2） of 0.894 and 0.980 for the two models, respectively. Optimum areas of 〉-80% Ni extraction and 〈5% Fe dissolution were obtained by the overlaid contours. Verification experiments in the optimum areas were conducted and the results indicate a close agreement with the predicted values obtained from the models.

Influence of Sulfation on the Catalytic Activity of Ni-ZrO_2 for NO Reduction with Propane in Excess Oxygen

Selective catalytic reduction （SCR） of nitric oxide with propane in excess oxygen was investigated on Ni-ZrO2 （NZ） and sulfated Ni-ZrO2 （SNZ）, prepared by coprecipitation from a mixture of nickel nitrate-zirconium oxychloride followed by modifying with （NH4）2SO4. It was found that sulfated Ni-ZrO2 catalyst showed higher activity for the SCR of NO with propane than that of Ni-ZrO2. The structural and surface properties of catalysts were studied by XRD, BET, SEM and FT-IR of pyridine adsorption. The experimental results indicated that the modification of （NH4）2SO4 resulted in the generation of strong BrOnsted and Lewis acid sites and promoted the dispersion of the Ni species, which could lead to higher NO conversion and propane efficiency in NO reduction.

Preparation of supported nano-copper oxide and its sulfation kinetics

CuO/γ-Al2O3 sorbents were prepared by means of impregnation. Thermogravimetric technique was used to study the sulfation of CuO/γ-Al2O3 sorbents. The sulfation tests were performed using gas containing 0.1%-0.9% SO2, 5% O2, 3% H2O steam, and N2 as the balance. Experimental conditions including temperature, SO2 concentration and pore structure were studied. The sulfation experiment results show that the sulfation reaction rate increases with increasing temperature and SO2 concentration, and the surface and pore volume decrease after sulfation. Sulfation kinetics analysis shows that the reaction between CuO/γ-Al2O3 and SO2 obeys pore-blocking model well. Proportionality (pore-blocking constant) 1/λ decreases with increasing temperature. The activation energy and reaction order with respect to SO2 obtained are 37.9 kJ/mol and the first order, respectively. The existing state of CuO exerts an influence on activation energy.

Sulfation behavior of CuO/γ-Al_2O_3 sorbent for the removal of SO_2 from flue gas

CuO/γ-Al2O3 has been considered as a promising and recycling sorbent to remove sulfur dioxide from flue gas. In this study, a series of CuO/γ-Al2O3 sorbents with different CuO loadings were prepared by impregnation. The monolayer coverage of CuO supported on γ-Al2O3 determined by X-ray quantitative analysis was 0.275 g CuO/g （γ-Al2O3）. Below the monolayer coverage, CuO was found highly dispersed on γ-Al2O3. Thermogravimetric technique was used to study sulfation kinetics and sulfation recycling. It was found that the Langmuir kinetic adsorption model described well the experimental data at the rapid sulfation region of the CuO/γ-Al2O3 sorbent. The adsorption activation energy was 19.98 kJ/mol and the pre-exponential factor was 9.97× 10^-5 s^-1.Pa^-1. The CuO/γ-Al2O3 sorbent has shown good performance on regeneration, but long sulfation time might cause the deactivation of the CuO/γ-Al2O3 sorbent. It was also seen that the sulfated γ-Al2O3 support could not be reduced at 400℃.

Recovery of Copper from Copper Sulfide Concentrate by Sulfation Roasting

Sulfation roasting was studied to extract copper from the copper sulfide concentrate. Sodium sulfite was added as sulfation agent to the copper sulfide concentrate during roasting in this study. Sulfur removal rate at different roasting temperatures was investigated, and the effects of roasting temperature, roasting time, and the amount of sodium sulfite on copper extraction were studied. Copper extraction higher than 96% was achieved at optimum roasting conditions.

Preparation of synthetic rutile via selective sulfation of ilmenite with(NH4)2SO4 followed by targeted removal of impurities

This paper describes a novel, facile chemical pathway for preparing synthetic rutile from ilmenite. The pathway consists of two primary units, i.e., selectively sulfating ilmenite, which was realized via roasting ilmenite with(NH_4)_2SO_4followed by selective thermal decomposition of the sulfated ilmenite, and targeted leaching of the impurities. The effects of the process parameters were systematically investigated. The results showed that the optimum sulfation conditions were a mass ratio of(NH_4)_2SO_4to ilmenite of 14, temperature of 360 °C, and time of 120 min with a sulfation ratio of ~ 95%. The optimum thermal decomposition conditions were480 °C in N_2 atmosphere, and nearly all Ti OSO_4 were decomposed with co-decomposition of Fe SO_4 of 23%. For acid leaching, the optimum conditions were 2.5 wt% HCl, 98 °C and 120 min. Under those conditions, 94.2% iron was removed with a Ti O_2 dissolution loss b 1%. For alkali leaching, 67% Si O_2 was removed in 5 wt% Na OH at102 °C for 1 h. A synthetic rutile with a Ti O_2 content N 92 wt% and total Mg O + Ca O b 1.5 wt% was obtained.Based on these results, a schematic flowsheet was proposed. Additionally, it was found that the decomposition of Fe SO_4 mixed with Ti OSO_4 under N_2was inhibited due to its oxidation to a higher thermal stability Fe_2(SO_4)_3by oxygen emitted from the decomposition of Ti OSO_4. At the same time, Ti OSO_4 decomposition was promoted due to the immediate in situ consumption of oxygen by Fe SO_4. The synergetic effect might be responsible for the enhanced selectivity of sulfated ilmenite thermal decomposition.

SULFATION OF PACHYMAN WITH CHLOROSULFONIC ACID USING THE IMPROVED WOLFROM METHOD

High purity polysaccharide of pachyman was isolated from the powder of Poria cocos sclerotium with an yield of 77.8%. The intrinsic viscosity of polysaccharide was found to be 78.95 mL/g in DMSO solution at 25℃. The isolated polysaccharide was reacted with chlorosulfonic acid to obtain pachyman sulfate using the improved Wolfrom method. The results of the orthogonality experiment on the sulfation reaction identified that the effectiveness of the reaction conditions on the degree of sulfation and the value of intrinsic viscosity is in the following order： molar ratio of chlorosulfonic acid to glucoside （3-5） 〉 reaction temperature （60-80℃） 〉 reaction time （1 2 h）, The kinetic studies of the pachyman sulfation indicated that the hydrolysis is accompanied with the sulfation process. The decrease in intrinsic viscosity of the sulfated pachyman is proportional to the increase in the degree of sulfation under the mild reaction conditions of 〈 80℃, chlorosulfonic acid/glucoside mole ratio 〈 5, and reaction time 〈 2 h. Beyond the above reaction conditions, excessive loss of --OH group occurs during hydrolysis. The NMR results indicated a complete sulfation on C-6 and a partial sulfation on the C-2 and C-4 of glucoside.

Sulfation of chondroitin and bile acids converges to antagonize Wnt/β-catenin signaling and inhibit APC deficiency-induced gut tumorigenesis

Sulfation is a crucial and prevalent conjugation reaction involved in cellular processes and mammalian physiology.3’-Phosphoadenosine 5’-phosphosulfate(PAPS)synthase 2(PAPSS2)is the primary enzyme to generate the universal sulfonate donor PAPS.The involvement of PAPSS2-mediated sulfation in adenomatous polyposis coli(APC)mutation-promoted colonic carcinogenesis has not been reported.Here,we showed that the expression of PAPSS2 was decreased in human colon tumors along with cancer stages,and the lower expression of PAPSS2 was correlated with poor prognosis in advanced colon cancer.Gut epithelial-specific heterozygous Apc deficient and Papss2-knockout(Apc^(Δgut-Het)Papss2^(Δgut))mice were created,and the phenotypes were compared to the spontaneous intestinal tumorigenesis of Apc^(Δgut-Het)mice.Apc^(Δgut-Het)Papss2^(Δgutmice) were more sensitive to gut tumorigenesis,which was mechanistically accounted for by the activation of Wnt/β-catenin signaling pathway due to the suppression of chondroitin sulfation and inhibition of the farnesoid X receptor(FXR)-transducin-like enhancer of split 3(TLE3)gene regulatory axis.Chondroitin sulfate supplementation in Apc^(Δgut-Het)Papss2^(Δgutmice) alleviated intestinal tumorigenesis.In summary,we have uncovered the protective role of PAPSS2-mediated chondroitin sulfation and bile acids-FXR-TLE3 activation in the prevention of gut carcinogenesis via the antagonization of Wnt/β-catenin signaling.Chondroitin sulfate may be explored as a therapeutic agent for Papss2 deficiency-associated colonic carcinogenesis.

Selective lithium recovery from black powder of spent lithiumion batteries via sulfation reaction:phase conversion and impurities influence

The aim of this study is to present a new understanding for the selective lithium recovery from spent lithium-ion batteries(LIBs)via sulfation roasting.The composition of roasting products and reaction behavior of impurity elements were analyzed through thermodynamic calculations.Then,the effects of sulfuric acid dosage,roasting temperature,roasting time,and impurity elements were assessed on the leaching efficiency of valuable metals.Characterization methods such as X-ray diffraction(XRD),scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),and X-ray photoelectron spectroscopy(XPS)were employed to analyze the phase transformation mechanism during roasting process.The results indicate that after sulfation roasting(n(H_(2)SO_(4)):n(Li)=0.5,550℃,2 h),94%lithium can be selectively recovered by water leaching and more than 95%Ni,Co,and Mn can be leached through acid leaching without the addition of reduction agent.During the sulfation roasting process,the lithium in LiNi_(x)Mn_(y)Co_zO_(2)is mainly converted to Li_(2)SO_(4),while the Ni,Co and Mn are first transformed to sulfate and then converted into oxide form.In addition,impurity elements such as Al and F will combine with lithium to form LiF and LiAlO_(2),which will reduce the leaching rate of lithium.These results provide a new understanding on the mechanisms of phase conversion during sulfation roasting and reveal the influence of impurity elements for the lithium recovery from spent LIBs.

Getting insights into gas-phase sulfation effect on catalytic performance of praseodymium oxides in NH_(3)-SCR of NO

Sulfation treatment has been widely used to promote the catalytic performance of ceria(CeO_(2))based catalysts for the selective catalytic reduction of NO by NH_(3)(NH_(3)-SCR of NO).Praseodymium oxide(PrO_(x)),another commonly used rare earth material with similar structural properties as CeO_(2),also shows satistactory redox properties due to the facile redox cycle of Pr^(3+)■Pr^(4+).In this work,gas phase sulfation treatment with varied duration was performed on PrO_(x) at 200℃,and the NH_(3)-SCR activity of sulfated PrO_(x) was evaluated.Based on the results of systematic characterizations(e.g.,N_(2)-physisorption,NH_(3) oxidation,NO oxidation,in situ diffuse Fourier transform infrared spectroscopy),it is revealed that the catalytic performance of sulfated PrO_(x)is highly dependent on the sulfation time(or the amount of sulfate species deposited on PrO_(x)),which has a significant impact on the competitive reaction between NH_(3) oxidation and NH_(3)-SCR of NO,thus determining the NH_(3)-SCR activity of PrO_(x).This work provides new insight into tuning the interaction between PrO_(x) surface and reactants(NO,NH_(3))via sulfation treatment,which cam guide the design and application of PrO_(x)based catalysts for NH_(3)-SCR of NO in the future.

Tyrosylprotein sulfotransferase suppresses ABA signaling via sulfation of SnRK2.2/2.3/2.6

Phytohormone abscisic acid(ABA)plays vital roles in stress tolerance,while long-term overactivation of ABA signaling suppresses plant growth and development.However,the braking mechanism of ABA responses is not clear.Protein tyrosine sulfation catalyzed by tyrosylprotein sulfotransferase(TPST)is a critical post-translational modification.Through genetic screening,we identified a tpst mutant in Arabidopsis that was hypersensitive to ABA.In-depth analysis revealed that TPST could interact with and sulfate SnRK2.2/2.3/2.6,which accelerated their degradation and weakened the ABA signaling.Taken together,these findings uncovered a novel mechanism of desensitizing ABA responses via protein sulfation.

Chemical protein synthesis elucidates key modulation mechanism of the tyrosine-O-sulfation in inducing strengthened inhibitory activity of hirudin

Tyrosine sulfation is an important post-translational modification that enhances the inhibitory activity of hirudin.Herein,we developed a facile synthetic strategy to afford the sulfated hirudins with up to three modifications and in multi-milligram scales,after a single HPLC purification step.Through these synthetic proteins,a novel type of modulation mechanism exhibited by tyrosine sulfation was proposed,which would help to delineate the structure-function relationships in other sulfated proteins and more importantly,to serve as a basis for the development of related antithrombotic agents.

Sulfation of the extracellular polysaccharide from the edible fungus Stropharia rugosoannulata with its antioxidant activity

An acidic extracellular polysaccharide(EPS)was gained from Stropharia rugosoannulata fermentation broth by the alcohol precipitate method.Sulfated derivative of EPS(S-EPS)was gained by chlorosulfonic acid-pyridine method and the conditions were as follows:pyridine as the reaction solvent,temperature 80°C,and reaction time 90 min.The chemical structure and chain conformation of EPS and S-EPS were characterized by FT-IR,NMR and size exclusion chromatography(SEC)coupled with multi-angle laser light scattering(MALLS)detection.FT-IR spectra indicated the sulfated group was linked to the polymer.The EPS mainly consists of mannose,glucose and glucuronic acid,and the glycosidic bond type is mainly(1→4)-linked and(1→6)-linked.C6 and C2 were substituted by sulfate groups.The EPS was degraded into smaller molecular weight(Mw)polysaccharides with the larger molecular size(Rg)after sulfation and S-EPS has better hydrophilicity.Moreover,the sulfated derivative S-EPS was found to have a better scavenging ability on hydroxyl radicals than EPS.It proved that the chemical modification of S.rugosoannulata polysaccharides by sulfation effectively enhanced their antioxidant activity.

Photobiomodulation inhibits the expression of chondroitin sulfate proteoglycans after spinal cord injury via the Sox9 pathway

Both glial cells and glia scar greatly affect the development of spinal cord injury and have become hot spots in research on spinal cord injury treatment.The cellular deposition of dense extracellular matrix proteins such as chondroitin sulfate proteoglycans inside and around the glial scar is known to affect axonal growth and be a major obstacle to autogenous repair.These proteins are thus candidate targets for spinal cord injury therapy.Our previous studies demonstrated that 810 nm photo biomodulation inhibited the formation of chondroitin sulfate proteoglycans after spinal cord injury and greatly improved motor function in model animals.However,the specific mechanism and potential targets involved remain to be clarified.In this study,to investigate the therapeutic effect of photo biomodulation,we established a mouse model of spinal cord injury by T9 clamping and irradiated the injury site at a power density of 50 mW/cm~2 for 50 minutes once a day for 7 consecutive days.We found that photobiomodulation greatly restored motor function in mice and down regulated chondroitin sulfate proteoglycan expression in the injured spinal cord.Bioinformatics analysis revealed that photobiomodulation inhibited the expression of proteoglycan-related genes induced by spinal cord injury,and versican,a type of proteoglycan,was one of the most markedly changed molecules.Immunofluorescence staining showed that after spinal cord injury,versican was present in astrocytes in spinal cord tissue.The expression of versican in primary astrocytes cultured in vitro increased after inflammation induction,whereas photobiomodulation inhibited the expression of ve rsican.Furthermore,we found that the increased levels of p-Smad3,p-P38 and p-Erk in inflammatory astrocytes were reduced after photobiomodulation treatment and after delivery of inhibitors including FR 180204,(E)-SIS3,and SB 202190.This suggests that Sma d 3/Sox9 and MAP K/Sox9 pathways may be involved in the effects of photobiomodulation.In summary,our findings show that photobiomodulation modulates the expression of chondroitin sulfate proteoglycans,and versican is one of the key target molecules of photo biomodulation.MAPK/Sox9 and Smad3/Sox9 pathways may play a role in the effects of photo biomodulation on chondroitin sulfate proteoglycan accumulation after spinal cord injury.

Glycosylation and sulfation of emodin by Gliocladium deliquescens NRRL 1086

The present study was designed to explore the substrate scope and biocatalytic capability of Gliocladium deliquescens NRRL 1086 on phenolic natural products. Emodin was subjected to the fermentation culture of Gliocladium deliquescens NRRL 1086 according to the standard two-stage protocol. The biotransformation process was monitored by HPLC-DAD-MS, the main product was isolated by column chromatography, and the structure was elucidated on the basis of NMR spectroscopy. Emodin could be fully metabolized by Gliocladium deliquescens NRRL 1086, resulting in high yield of emodin 6-O-β-D-glucopyranoside and small amount of sulfated product. In conclusion, our results may provide a convenient method to prepare emodin 6-O-β-D-glucopyranoside and the microbe catalyzed glucosylation/sulfation will give an inspiration to pharmacokinetic model studies in vitro.

Mucopolysaccharidosis typeⅢB:a current review and exploration of the AAV therapy landscape

Mucopolysaccharidoses typeⅢB is a rare genetic disorder caused by mutations in the gene that encodes for N-acetyl-alpha-glucosaminidase.This results in the aggregation of heparan sulfate polysaccharides within cell lysosomes that leads to progressive and severe debilitating neurological dysfunction.Current treatment options are expensive,limited,and presently there are no approved cures for mucopolysaccharidoses typeⅢB.Adeno-associated virus gene therapy has significantly advanced the field forward,allowing researchers to successfully design,enhance,and improve potential cures.Our group recently published an effective treatment using a codon-optimized triple mutant adeno-associated virus 8 vector that restores N-acetyl-alpha-glucosaminidase levels,auditory function,and lifespan in the murine model for mucopolysaccharidoses typeⅢB to that seen in healthy mice.Here,we review the current state of the field in relation to the capsid landscape,adeno-associated virus gene therapy and its successes and challenges in the clinic,and how novel adenoassociated virus capsid designs have evolved research in the mucopolysaccharidoses typeⅢB field.

Sulfated Cyclocarya paliurus polysaccharides exert immunomodulatory potential on macrophages via Toll-like receptor 4 mediated MAPK/NF-κB signaling pathways

The biological activity of plant polysaccharides can be enhanced by sulfated modification.In this study,the immunomodulatory effect of sulfated Cyclocarya paliurus polysaccharides(SCP3)on macrophages RAW264.7 and its potential molecular mechanism were investigated.Results showed that SCP3 at 25-100μg/m L increased viability and improved phagocytosis of RAW264.7 cells.Meanwhile,SCP3 could activate mitogen-activated protein kinase(MAPK)and nuclear factor kappa B(NF-κB)signaling pathways,which increased the phosphorylation of Erk1/2,JNK,p38 and NF-κB p65,promoting secretion of cytokines tumor necrosis factorα(TNF-α),interleukin 6(IL-6)and nitric oxide(NO)as well as the production of reactive oxygen species(ROS).In addition,Toll-like receptor 4(TLR4)receptor inhibitors were able to block the production of NO and TNF-αby SCP3-stimulated macrophages.Based on Western blot analysis and validation using specific inhibitors against MAPK and NF-κB signaling pathways,the results demonstrated that SCP3 induced macrophages activation and enhanced TNF-αand NO production via TLR4-mediated MAPK and NF-κB pathways.In summary,SCP3 has significant immunomodulatory potential.The underlying molecular mechanism was that SCP3 activates macrophages via TLR4 receptors to promote ROS production,which in turn activates the downstream MAPK/NF-κB signaling pathway and then increases the secretion levels of cytokines and NO.

Influence of Recycled Concrete Fine Powder on Durability of Cement Mortar

In this paper,the durability of cement mortar prepared with a recycled-concrete fine powder(RFP)was examined;including the analysis of a variety of aspects,such as the carbonization,sulfate attack and chloride ion erosion resistance.The results indicate that the influence of RFP on these three aspects is different.The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10%RFP decreased by 13.3%and 28.19%.With a further increase in the RFP content,interconnected pores formed between the RFP particles,leading to an acceleration of the penetration rate of CO_(2)and Cl^(−).When the RFP content was less than 50%,the corrosion resistance coefficient of the compressive strength of the mortar was 0.84-1.05 after 90 days of sulfate attack.But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production.Scanning electron microscope(SEM)analysis has confirmed that 10%RFP contributes to the formation of a dense microstructure in the cement mortar.

Preparation of α-High Strength Gypsum from Flue Gas Desulfurization Gypsum Pretreated by Hydrothermal-aging Method

The synthesis of α-calcium sulfate hemihydrate (α-CSH) from flue gas desulfurization (FGD)gypsum is a good way to realize the comprehensive utilization of FGD gypsum. To obtainα-CSH with the satisfactory performances, a facile hydrothermal-aging pretreatment process for FGD gypsum raw materials was proposed, where FGD gypsum was firstly hydrothermally converted to α-CSH whiskers, and α-CSH whiskers were further hydrated to synthesize CaSO4·2H2O (CSD) by aging under the regulation of N,N'-methylenebisacrylamide (MBA). The effects of aging time, MBA addition, aging temperature, and pH on the morphology of the synthesized CSD were investigated. The synthesized CSD crystals exhibit highly uniform prismatic morphology with the length of ca 100μm and the whiteness of 91.56%. The regulation mechanism of MBA was also illustrated. The synthesized CSD crystals with prismatic morphology were further used as raw materials to synthesize the short columnar α-CSH. The absolute dry compressive strength of paste prepared from the short columnar α-CSH is 40.85 MPa, which reaches α40 strength grade.

Differences in the effects and action modes of gut commensals against dextran sulfate sodium-induced intestinal inflammation

Inflammatory bowel disease(IBD)is a complex relapsing inflammatory disease in the gut and is driven by complicated host-gut microbiome interactions.Gut commensals have shown different functions in IBD prevention and treatment.To gain a mechanistic understanding of how different commensals affect intestinal inflammation,we compared the protective effects of 6 probiotics(belonging to the genera Akkermansia,Bifidobacterium,Clostridium,and Enterococcus)on dextran sulfate sodium(DSS)-induced colitis in mice with or without gut microbiota.Anti-inflammatory properties(ratio of interleukin(IL)-10 and IL-12)of these strains were also evaluated in an in vitro mesenteric lymph nodes(MLN)co-culture system.Results showed that 4 probiotics(belonging to the species Bifidobacterium breve,Bifidobacterium bifidum,and Enterococcus faecalis)can alleviate colitis in normal mice.The probiotic strains differed in regulating the intestinal microbiota,cytokines(IL-10,IL-1βand interferon(IFN)-γ),and tight junction function(Zonulin-1 and Occludin).By constrast,Akkermansia muciniphila AH39 and Clostridium butyricum FHuNHHMY49T1 were not protective.Interestingly,B.breve JSNJJNM2 with high anti-inflammatory potential in the MLN model could relieve colitis symptoms in antibiotic cocktail(Abx)-treated mice.Meanwhile,E.faecalis FJSWX25M1induced low levels of cytokines in vitro and showed no beneficial effects.Therefore,we provided insight into the clinical application of probiotics in IBD treatment.