Ball-milling MoS_2/carbon black hybrid material for catalyzing hydrogen evolution reaction in acidic medium

Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium, The activity of as-prepared MoS2 had a strong dependence on the ball milling time, Furthermore, Ketjen Black EC 300J was added into the ball-milled MoS2 followed by a second ball milling, and the resultant MoS2/carbon black hybrid material showed a much higher HER activity than MoS2 and carbon black alone. The enhanced activity of the MoS2/carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of MoS） and excellent electrical coupling to the underlving carbon network.

An acidic medium-compatible deep-near-infrared dye for in vivo imaging

In vivo imaging in the deep near-infrared(NIR)spectral region,that is,beyond 800 nm,has become popular due to its penetration depth.While imaging of the neutral medium/tissue has been repeatedly showcased,imaging of the high-acidic medium remains challenging partly because of the high-lying HOMO orbital and hence a high pKa of the electron-donating group of the NIR fluorophores.We devised a novel electron-donating group(D6)with which we further synthesized ECJ.ECJ exhibits an absorption wavelength beyond 900 nm and is fluorescent.Its pKa was found to be lower than zero,rendering it suitable for bioimaging of a highly-acidic medium.Its potential for practical applications was showcased in proof-of-concept in vivo imaging with a mouse model.

Zeolitic germanosilicate analogue to pharmacosiderite crystallized in an acidic medium

Zeolites are typically synthesized in alkaline or fluoride-containing near-neutral media.Sophisticated organic structure-directing agents have been investigated for such systems with the aim of discovering materials with unprecedented structures and properties for novel technical applications.In contrast,zeolite crystallization in strongly acidic media has yet to be explored.This study demonstrates that a zeolitic silicate phase crystallizes from acidic gels using trimethylamine as an organic additive with the composition 1 SiO_(2):0.3 TMA:0.3 HCl:0.15 HF:55 H_(2)O:(0.1-0.4)GeO_(2).This phase has an interrupted four-connected framework analog to the octahedron/tetrahedron-mixed framework of the mineral family pharmacosiderite.In comparison to the pharmacosiderite-type HK_(3)(Ge_(7)O_(16))(H_(2)O)_(4),the four GeO_(6)-octahedra forming the central[HGe_(4)O_(4)O_(12)]-cluster are replaced by four SiO_(4)-tetrahedra in a[Si_(4)O_(6)(OH)2.89]-unit in the new phase.However,the structure is distorted and may contain connectivity and point defects;thus,healing by the occasional incorporation of GeO_(6)-units is necessary.The refined unit cell has a cubic symmetry,space group P-43m(#215),with a=7.7005(1)Å.Acidic-medium synthesis is a useful way to find new zeolites that move in a fundamentally different direction from sophisticated organic structure-directing agents.

Comparison of electrochemical dissolution of chalcopyrite and bornite in acid culture medium

The electrochemical dissolution process of chalcopyrite and bornite in acid bacteria culture medium was investigated by electrochemical measurements and X-ray photoelectron spectroscopy（XPS） analysis. Bornite was much easier to be oxidized rather than to be reduced, and chalcopyrite was difficult to be both oxidized and reduced. The relatively higher copper extraction of bornite dissolution can be attributed to its higher oxidation rate. Covellite（CuS） was detected as the intermediate species during the dissolution processes of both bornite and chalcopyrite. Bornite dissolution was preferred to be a direct oxidation pathway, in which bornite was directly oxidized to covellite（CuS） and cupric ions, and the formed covellite（CuS） may inhibit the further dissolution. Chalcopyrite dissolution was preferred to be a continuous reduction-oxidation pathway, in which chalcopyrite was initially reduced to bornite, then oxidized to covellite（CuS）, and the initial reduction reaction was the rate-limiting step.

揭示氨对正己酸生产影响的机制——影响途径、关键酶和微生物

n-Caproate,which is produced via chain elongation(CE)using waste biomass,can supply various fossilderived products,thus advancing the realization of carbon neutrality.Ammonia released from the degradation of nitrogen-rich waste biomass can act as a nutrient or an inhibitor in anaerobic bioprocesses,including CE,with the distinction being primarily dependent on its concentration.Currently,the optimal concentration of ammonia and the threshold of toxicity for open-culture n-caproate production using ethanol as an electron donor,along with the underlying mechanisms,remain unclear.This study revealed that the optimal concentration of ammonia for n-caproate production was 2.0 g∙L^(-1),whereas concentrations exceeding this threshold markedly suppressed the CE performance.Exploration of the mechanism revealed the involvement of two forms of ammonia(i.e.,ammonium ions and free ammonia)in this inhibitory behavior.High ammonia levels(5.0 g∙L^(-1))induced excessive ethanol oxidation and suppressed the reverse β-oxidation(RBO)process,directly leading to the enhanced activities of enzymes(phosphotransacetylase and acetate kinase)responsible for acetate formation and diminished activities of butyryl-coenzyme A(CoA):acetyl-CoA transferase,caproyl-CoA:butyryl-CoA transferase,and caproyl-CoA:acetyl-CoA transferase that are involved in the syntheses of n-butyrate and n-caproate.Furthermore,the composition of the microbial community shifted from Paraclostridium dominance(at 0.1 g∙L^(-1)ammonia)to a co-dominance of Fermentimonas,Clostridium sensu stricto 12,and Clostridium sensu stricto 15 at 2.0 g∙L^(-1)ammonia.However,these CE-functional bacteria were mostly absent in the presence of excessive ammonia(5.0 g∙L^(-1)ammonia).Metagenomic analysis revealed the upregulation of functions such as RBO,fatty acid synthesis,K^(+)efflux,adenosine triphosphatase(ATPase)metabolism,and metal cation export in the presence of 2.0 g∙L^(-1)ammonia,collectively contributing to enhanced n-caproate production.Conversely,the aforementioned functions(excluding metal cation export)and K^(+)influx were suppressed by excessive ammonia,undermining both ammonia detoxification and n-caproate biosynthesis.The comprehensive elucidation of ammonia-driven mechanisms influencing n-caproate production,as provided in this study,is expected to inspire researchers to devise effective strategies to alleviate ammonia-induced inhibition.

Case Report: Carnitine Palmitoyl Transferase II (CPT II) Deficiency

Carnitine Palmitoyl Transferase II (CPTII) is a very important enzyme that helps with the oxidation of long-chain fatty acid to produce energy. Deficiency in CPTII will lead to energy deficiency in the case of fasting and the accumulation of the long chain fatty in the body. There are three types of CPT II deficiency, the myopathic form, the severe infantile hepatocardiomuscular form and the lethal neonatal form. They are all inherited as an autosomal recessive. Diagnosis of the CPTII are 1) tandem mass spectrometry (MS/MS) in adult form and 2) CPTII polymorphism (F352C), which is linked to reducing the activity of CPTII in infantile form [1]. Glucose is the primary management and medium-chain fatty acid is an alternative due to the bypass of the CPTII enzyme in the pathway. For the prevention of CPTII deficiency are to avoid long chain fatty acid (C12-fatty acid), fasting, prolonged exercise, known triggers, and certain medications such as anti-epileptics and general anesthesia. During the rhabdomyolysis and myoglobinuria attack, it is very important to maintain hydration to avoid acute renal failure. If, however, renal failure occurs, dialysis is recommended. We present a case of a 27-year-old African American woman with the significant past medical history of CPT II deficiency leading to recurrent rhabdomyolysis and myoglobinuria. Together with all the research studies from diagnosis to treatment of CPTII deficiency will help in clinical management of patients. And this case report will add to the existing case reports of patients who have CPTII deficiency in terms of how we diagnose, how we treat, and how we prevent symptoms from re-occurring.

Synergistic extraction of cerium from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester and Di-(2-ethyl hexyl) phosphoric acid as extractant

Synergistic extraction of cerium（IV） from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester（HEH/EHP, HL） and Di-（2-ethyl hexyl） phosphoric acid（HDEHP, HA） as extractant was investigated.The results indicated that the maximum synergistic enhancement coefficients were obtained at the mole fraction of HEH/EHP=0.6, and cerium（IV） was extracted into organic phase in the form of Ce（SO4）0.5HL2A2.A cation exchange mechanism was proposed for the synergistic extraction of Ce（IV）.The equilibrium constants and thermodynamic functions such as △G, △H, and △S were determined in the extraction of Ce（IV） from sulfuric medium using mixture of HEH/EHP and HDEHP.

Extraction of cerium(Ⅳ) using tributyl phosphate impregnated resin from nitric acid medium

Tributyl phosphate （TBP） solvent was used for impregnation into Amberlite XAD-16 nonionic polymeric resin beads using the wet method to prepare solvent impregnated resin （SIR）. Undiluted TBP in a ratio to the resin support （volume to mass） of 6.0 at room temperature （RT） in 24 h was impregnated the resin with a mass ratio of 1.944, while the prepared gross sample of SIR at the ratio of solvent to resin of 3.0 was impregnated with a mass ratio of 1.88. Cerium（Ⅳ） oxide concentrate, prepared from crude Egyptian monazite sand, containing 37% cerium, 1.6% thorium and about 40% the other trivalent rare earth oxides, was used to prepare cerium（Ⅳ） nitrate solution for extraction using the prepared SIR. The impregnated resin was satisfactory for Ce（Ⅳ） extraction from nitric acid medium at room temperature. Cerium loading capacity of the impregnated resin reached 95.6% of the calculated theoretical capacity （173 g/kg （Ce/SIR）） under the conditions of 51.57 g/L cerium and 2.48 g/L thorium, 5.0 mol/L free nitric acid, solution to resin ratio of 10.0 and contacting the phases for 5.0 min. The loading capacity reached 98.75% when cerium concentration was increased to 91.43 g/L under the same conditions.

Leaching Behavior and Mechanism of Cement Solidified Heavy Metal Pb in Acid Medium

The relationship between Pb leaching concentration and the solution＇s pH with time was analyzed when cement in its solidified form was leached in an acid medium. The effects of the particle size of the solidified form, the cement adding method, and the hydration degree on Pb solidification were also investigated. The experimental results indicate that cement is quickly dissolved and hydrated in the acid medium, forming a C-S-H gel or silicic acid sol with good adsorption. When cement-Pb solidified form is leached in an acetate solution, the hydrated product erodes with time, so the Pb concentration increases slightly in the beginning. Then, some of the Pb ions are absorbed by the newly generated silicic acid sol, C-S-H. Others produce Pb（OH）2 precipitation for secondary solidification, leading to a gradual decrease in the Pb concentration in a leaching time of more than two hours. Moreover, the particle size of the solidified form has important effects on the Pb dissolution. When the amount of added cement is low, with a pH of less than 9.5, the solidification affects the sequence of the original cement powder, the cement hydrated powder, and the cement- Pb solidified form. When the added amount of cement increases with a pH of more than 11, the effect of adding methods on solidification decreases, and the solidified form is a little better than others.

Acidity and Rare Earth Concentration Effects on Ytterbium Purification by an Electrolysis Reduction in H_2SO_4 Medium

Ytterbium purification by an electrolysis reduction in sulfuric acid medium was investigated without nitrogen or argon protection, in which Ru-Ir-Ti alloy nets and mercury were used as anode and cathode, respectively. How the conditions such as the acidities of cathode and anode solutions, and the concentration of Yb（ Ⅲ ） to affect the circuit and ratio of Yb（ Ⅱ ）/Yb （ Ⅲ ） in electrolysis reduction were studied.

Synthesis of ZSM-22/SAPO-11 composite molecular sieve-based catalysts with small crystallites and superior n-alkane hydroisomerization performance

To improve oil quality,ZSM-22/SAPO-11 composite molecular sieves were synthesized by adding ZSM-22 into a synthetic gel of SAPO-11 for n-decane hydroisomerization.The mass ratios of ZSM-22/(ZSM-22+SAPO-11)in the composite molecular sieves were optimized and the optimal ZSM-22/SAPO-11 composite(ZS-9)was obtained.The electrostatic repulsions between the ZSM-22 precursors and the SAPO-11 crystalline nuclei produced small ZSM-22 and SAPO-11 crystallites in ZS-9,which increased the specific surface area and mesopore volume and thereby exposed more acid sites.In comparison with conventional SAPO-11,ZSM-22 and their mechanical mixture,ZS-9 with smaller crystallites and the optimal medium and strong Brønsted acid centers(MSBAC)content displayed a higher yield of branched C_(10) isomers(81.6%),lower cracking selectivity(11.9%)and excellent stability.The correlation between the i-C_(10) selectivity and the MSBAC density of molecular sieves indicated that the selectivity for branched C_(10) isomers first increased and then decreased with increasing MSBAC density on the molecular sieves,and the maximum selectivity(87.7%)occurred with a density of 9.6×10^(−2)μmol m^(−2).

Lactate-mediated medium-chain fatty acid production from expired dairy and beverage waste

Fruits,vegetables,and dairy products are typically the primary sources of household food waste.Currently,anaerobic digestion is the most used bioprocess for the treatment of food waste with concomitant generation of biogas.However,to achieve a circular carbon economy,the organics in food waste should be converted to new chemicals with higher value than energy.Here we demonstrate the feasibility of medium-chain carboxylic acid(MCCA)production from expired dairy and beverage waste via a chain elongation platform mediated by lactate.In a two-stage fermentation process,the first stage with optimized operational conditions,including varying temperatures and organic loading rates,transformed expired dairy and beverage waste into lactate at a concentration higher than 900 mM C at 43℃.This lactate was then used to produce>500 mM C caproate and>300 mM C butyrate via microbial chain elongation.Predominantly,lactate-producing microbes such as Lactobacillus and Lacticaseibacillus were regulated by temperature and could be highly enriched under mesophilic conditions in the firststage reactor.In the second-stage chain elongation reactor,the dominating microbes were primarily from the genera Megasphaera and Caproiciproducens,shaped by varying feed and inoculum sources.Cooccurrence network analysis revealed positive correlations among species from the genera Caproiciproducens,Ruminococcus,and CAG-352,as well as Megasphaera,Bacteroides,and Solobacterium,indicating strong microbial interactions that enhance caproate production.These findings suggest that producing MCCAs from expired dairy and beverage waste via lactate-mediated chain elongation is a viable method for sustainable waste management and could serve as a chemical production platform in the context of building a circular bioeconomy.

Investigate the Corrosion Inhibition of Mild Steel in Sulfuric Acid Solution by Thiosemicarbazide

Corrosion inhibition of mild steel in 0.5 mol/L H2SO4 was investigated in the absence and presence of different concentrations of thiosemicarbazide. The inhibition efficiency of thiosemicarbazide was studied by electrochemical impedance methods, potentiodynamic polarization and scanning electron microscopy at different inhibitor concentrations. Inhibition efficiency, corrosion rate and surface coverage were evaluated at different concentrations of thiosemicarbazide. Electrochemical impedance plots indicated that the presence of the inhibitors increased the charge transfer resistance of the corrosion process, increasing the inhibition efficiency. Polarization curves showed that this compound acted as mixed type inhibitor. The results of the investigation showed that this compound had good inhibiting properties for mild steel corrosion in 0.5 M sulfuric acid. The adsorption isotherm studies showed that Thiosemicarbazide adsorbed chemisorbed and formed a stable surface complex on the mild steel surface. And Langmuir obeyed the adsorption isotherm. Scanning electron microscopy analysis shows that, the surface morphology of the polished mild steel in the presence of thiosemicarbazide as inhibitor is smoother surface as compared with polished mild steel specimen in the absence of inhibitor.

Structure and Performance of Fe-N_x-C Catalyst for Oxygen Reduction Reaction Prepared by Vacuum Casting Method and the Second Pyrolysis

Affordable non-precious metal（NPM） catalysts played a vital role in the wide application of polymer electrolyte membrane fuel cells（PEMFC）. In current work, a facile vacuum casting reacting method based on vacuum casting was introduced to prepare Fe-N_x-C oxygen reduction reaction（ORR） catalysts with high efficient in acid medium. The catalysts were prepared with ammonium ferrous sulfate hexahydrate（AFS） and 1,10-phenanthroline monohydrate utilizing homemade mesoporous silica template. The heat treatment and its influence on structure and performance were systematically evaluated to achieve superior ORR performance and some clues were found. And 850 ℃ was found to be the best temperature for the first and second pyrolysis. The linear sweep voltammetry（LSV） results showed that there were only 18 mV slightly negative shifts of half-wave potential（E_（1/2）） of the optimal catalyst（749 mV） compared with the commercial Pt/C（20 μg·Pt·cm^-2）. Besides, I850 R also showed better electrochemical stability and methanol-tolerance than that of Pt/C. All evidences proved that our vacuum casting reacting strategy and heat treatment process were prospective for the future R＆D of high performance Fe-N_x-C ORR catalysts.

Dietary substitution of soybean oil with coconut oil in the absence of dietary antibiotics supports growth performance and immune function in nursery and grower pigs

Background:We hypothesized that supplementation of nursery and grower pig diets with coconut oil in the absence of antibiotics would yield maintenance of glucose homeostasis,growth performance,and immune function similar to what is achieved with nursery and grower pig diets containing antibiotics.Pigs received the same base treatment diets from d24(weaning)to d71 of age and had blood and fecal samples collected on d24,d31,d45 and d71 for measurement of whole blood glucose,serum insulin,cortisol and cytokines,and fecal microbiome.Pigs had weekly weights and daily feed consumption measured throughout the study.Animals were euthanized at d71 and subcutaneous fat and ileal contents were collected for assessment for fatty acids and microbiome,respectively.Diet treatments consisted of 2%soybean oil plus antibiotics(ABX;n=22),2%soybean oil without antibiotics(NABX;n=22),and 2%coconut oil without antibiotics(COC;n=22).Statistical analysis examined the effect of diet within each timepoint using a repeated measures ANOVA.Results:Pigs fed COC diet had decreased serum insulin levels,maintained feed intake,feed conversion and weight gain,and,based on serum cytokines and fecal microbiome,were immunologically similar to ABX-fed pigs.However,NABX-fed pigs performed similarly to the ABX-fed pigs in all parameters except for serum cytokines.Additionally,there was no difference in the incidence of diarrhea between any of the diet treatments.Conclusions:This study demonstrates that dietary antibiotics are not necessary to maintain growth performance in nursery and grower pigs.However,dietary antibiotics appear to modulate circulating cytokine levels.Dietary coconut oil is neither harmful nor helpful to growth performance or immune function in nursery and grower pigs but does modulate serum insulin levels.Therefore,while coconut oil fed at 2%by weight is a suitable substitute for dietary antibiotics,this study suggests that no substitute for dietary antibiotics is needed at all.

Analyses of concrete microcosmic structure in multi-media environment

The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decrease the service life of a concrete structure if improperly handled. In this paper the microstructure of concrete is observed by using Scanned Electric Microscope (SEM) through contrasting experiments in media of acid, alkali and salt with that of freezing-thawing in the same medium environment. This study is to supply a certain basis for changing traditional thinking of mechanical design and to combine construction reliability design with durability of concrete design.

Synthesis of mono and bis-4-methylpiperidiniummethyl-urea as corrosion inhibitors for steel in acidic media

Mono and bis-4-methylpiperidiniummethyl urea were synthesized,characterized and used as new corrosion inhibitors of mild steel in the acidic media.Inhibitory effect of two compounds on mild steel surface in the 1 mol·L^(–1 )sulphuric acid has been studied by a series of techniques,such as potentiodynamic polarization,weight loss and quantum chemical calculation methods.Potentiodynamic polarization measurements showed that two inhibitors are mixed type.All measurements showed that inhibition efficiencies enhanced with increase of inhibitor concentration.This reveals that inhibitive actions of inhibitors were mainly due to adsorption on mild steel surface.Density functional(DFT)calculations have been carried out for the title compounds by performing HF and DFT levels of theory using the standard 6-31G*basis set.

Adsorption of Ce(IV) in nitric acid medium by imidazolium anion exchange resin

N-methylimidazolium functionalized anion exchange resin in NO3 form （RNO3） was prepared and used for adsorption of Ce（Ⅳ） in nitric acid medimn. The adsorption amount increased with shaking time increasing and the adsorption equilibrium was obtained within 180 rain. Ce（Ⅳ） was partially reduced to Ce（Ⅲ） and the reduction percent of Ce（Ⅳ） increased with shaking time increasing. But RNO3 was more stable than other resins due to the high resistance to oxidation. A little increase of adsorption amount was found with concentration of HNO3 increasing. However, the reduction percent of Ce（Ⅳ） decreased with the increase of HNO3 concentration. The addition of NaNO3 decreased the adsorption amount of Ce（Ⅳ） on RNO3 due to the competitive anion exchange reaction. Ce（Ⅳ） was adsorbed on RNO3 in the form of Ce（Ⅳ） anion nitrato-complex. RNO3 and Ce（Ⅳ）-loaded RNO3 were characterized by fourier transform infrared （FT-IR） and thermogravimeric analysis （TGA）. Ce（Ⅳ） could be easily separated from RE（Ⅲ） solution by RNO3.

STUDIES ON THE EXTRACTION MECHANISM OF GOLD (Ⅲ) FROM HYDROCHLORIC ACID MEDIUM BY TRIPHENYLPHOSPHINE OXIDE (TPPO)

In studies on the extraction chemistry of gold, the extractants of alcohols, ethers, ketones and amines are widely used. The neutral extractants tributylphosphate (TBP) and trioctylphosphine oxide (TPPO) have been widely applied. A few experiments on the synthesis of solid complexes of transition metal ions with TPPO have been car-

Mechanism of powdered activated carbon enhancing caproate production

Caproate, produced by microbial chain elongation process, is potential to replace the diversified fossilbased products, contributing to carbon neutrality. However, its production performance is far from industrial application, so the cost-effective enhancement measures are highly needed. This study confirmed powdered activated carbon(PAC) has a significant effect on enhancing caproate production performance.The production, yield, and selectivity of caproate were improved by more than 1-fold by the optimized PAC dosage of 15 g/L, comparing with control. Mechanism investigation from a new visual angle showed that PAC accelerated ethanol oxidation to generate acetyl-Co A, and simultaneously boosted the efficiency of reverse β oxidation(RBO) by promoting the timely reaction of butyrate and acetyl-Co A to synthesis caproate. The addition of PAC also shifted the microbial community by enriching more caproateproducing bacteria but eliminating irrelevant ones. Furthermore, metagenomic analysis revealed that PAC effectively up-regulated the functional genes encoding key enzymes responsible for ethanol oxidation and RBO pathway, which was the root cause for the improved caproate production. This study presented the intrinsic insights into the mechanism of PAC promoting caproate generation, laying a foundation to the scale production of caproate.