Aqueous Products Research Articles

Evolution of N-Containing Compounds during Hydrothermal Liquefaction of Sewage Sludge

In this study, complementary techniques, including ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) and X-ray photoelectron spectroscopy (XPS), were applied to characterize the transformation of nitrogen components during hydrothermal liquefaction (HTL) of sewage sludge. Results showed that 3–35% of nitrogen in sludge was transferred into the biocrude product when using HTL reaction temperatures ranging from 200 to 350 °C, with the remaining nitrogen partitioning to aqueous, solid, and gaseous coproducts. N-containing organics in biocrude shifted to structures with higher H:C ratios when HTL reaction temperatures were increased, whereas an opposite trend was observed for O:C ratios of N-containing chemicals in biocrude and aqueous products. Accordingly, weighted averages of double-bond equivalents (DBEw) and aromatic index (AImod,w ) of N-containing products in biocrude decreased as reaction temperature increased, while AImod,w increased for products in the aqueous phase. These trends are consistent with cyclization/aromatization reactions, promoting the formation of N-containing products that partition predominantly to the aqueous phase. XPS analysis revealed that the proportion of amine-N in biocrude increased sharply with reaction temperature, whereas heterocyclic-N (pyridinic-N and pyrrolic-N) and nitrile-N structures were mainly concentrated in solid residues. Improved molecular insights can serve as the basis for optimizing nitrogen management and recovery operations during HTL of sewage sludge.

Visible-Light-Driven Methane Conversion with Oxygen Enabled by Atomically Precise Nickel Catalyst

It remains an extreme challenge to activate thermodynamically unfavorable, chemically inert methane molecules under mild conditions. Herein, we report a molecular-like nickel-thiolate hexameric clu...

Distribution and toxicity of polycyclic aromatic hydrocarbons during CaO-assisted hydrothermal carbonization of sewage sludge

Hydrothermal carbonization (HTC) of sewage sludge (SS) with and without calcium oxide (CaO) introduction was conducted at 160–240 °C, and the yield and distribution of polycyclic aromatic hydrocarbons (PAHs) were evaluated for the first time. PAHs (2972.99 μg/kg) and toxic equivalent quantity (TEQ) (373.09 μg/kg) yields in SS decreased by 13.61% and 14.65%, respectively, after treatment at 160 °C and substantially increased as temperatures increased. More PAHs were distributed in the hydrochar than in the aqueous products. Hydrochar yields decreased linearly with temperature, thus increasing PAH concentration in hydrochar; 6221.98 μg/kg of PAHs in hydrocar at 240 °C exceeded agricultural use standard limits. PAH and TEQ yields at 200 °C decreased by 5.55–15.98% and 2.88–3.54%, respectively, when 3–9% CaO was added, which could be ascribed to CaO inhibition in the free radical reaction for PAH generation. Additionally, 6% CaO addition substantially weakened the acceleration effect of high temperatures on PAH formation; the decrease of PAH yield at 240 °C was 22.14%, which is higher than that at other temperatures. Consequently, the PAH concentration in hydrochar declined by 2.33–22.37%. PAH content in hydrochar obtained from CaO-assisted HTC of SS fell within agriculture use standard limit and exhibits potential for use as a soil conditioner. However, condition with a CaO amount of 15% would significantly increase TEQ yields. Considering both PAH and TEQ yields and the ecological risks of PAHs in hydrochar derived from HTC of SS, the appropriate reaction conditions were found to be 200 °C with 3–6% added CaO.

On-line two-dimensional liquid chromatography hyphenated to mass spectrometry and ion mobility-mass spectrometry for the separation of carbohydrates from lignocellulosic biomass

Lignocellulosic biomass is a promising resource of renewable energy. Its transformation to ethanol requires efficient pretreatment leading to complex liquid mixtures made of hundreds of oxygenated analytes. A large part of the released compounds belong to the carbohydrates family. To overcome the complexity of such samples, a comprehensive on-line two-dimensional reversed-phase liquid chromatography hyphenated to high-resolution mass spectrometry (RPLC × RPLC-HRMS) was dedicated to the separation of carbohydrates and more specifically oligomers coming from pretreated lignocellulosic biomass. The first part of this study consisted in the optimization of such hyphenation (i.e. selection of stationary phases, mobile phases, sampling time, etc.). Then, the analytical method was applied to an industrial aqueous biomass product coming from the sulfuric acid-based pretreatment of a wheat straw. Around 70 well-resolved chromatographic peaks corresponding to oligomers were obtained. Occupation of the separation space between each chromatographic dimension was estimated to 75%. In the last part of this study, the interest of ion mobility-mass spectrometry in addition to RPLC × RPLC was discussed. Some examples highlighted the additional separation that can bring ion mobility to RPLC × RPLC-IMS-HRMS method. Using this four-dimensional hyphenation method, each analyte was described by two retention times, the collisional cross section and the molecular formula allowing to reach a level of detail never seen for biomass sample compositions.

On the reactivity of aqueous radiolysis products towards carbon black used in in-situ radiation-synthesis of catalytic nanoparticles in graphite electrodes

Enhanced electrochemical performance of graphite electrodes can be achieved by incorporation of catalytic nanoparticles. One promising method for incorporation is in-situ radiation-synthesis where the radiolysis of water is used to drive the process of particle formation on carbon black. A potential problem is the direct reaction between radiolysis products and carbon black. In this work the reactivities of radiolytically produced HO·, (CH3)2C·OH, e-aq and H2O2 towards carbon black were investigated at room temperature with a dose rate 0.124 Gy s−1. HO· was found to react with carbon black with a rate constant of 20 ± 5 m s−1. For (CH3)2C·OH the corresponding value is 0.8 ± 0.1 m s−1. The reactivity of e-aq towards carbon black is negligible compared to that of (CH3)2C·OH. At concentrations <0.05 mmol L−1, H2O2 can react with carbon black with a rate constant of (6.7 ± 0.4) × 10−10 m s−1 mainly due to adsorption. At higher H2O2 concentrations catalytic decomposition producing HO· is also observed. It was also observed that the presence of carbon black increases the radiolytic formation of H2O2. In addition, the impact of carbon black reactivity on the radiation-synthesis of nanoparticles is discussed with an example from the literature.

Immunomodulation Effect of Nypa fruticans Palm Vinegar

Vinegars are aqueous products of fermentation that are composed of acetic acid, water and other trace chemical components. Previous studies have shown that they have several beneficial effects for humans, such as anti-diabetic, anti-bacteria, antioxidant, anti-tumor or the enhancement of immune function. Nypa fruticans palm vinegar (NPV) is 1 of the vinegars that is usually used as a food ingredient. However, there are limited studies that have provided results to support its proposed immunomodulatory properties. This study investigated the immunomodulatory effects of NPV. Locally produced NPV from 3 different planting areas (fresh, brackish and saline water) of the Nakhon Si Thammarat province in Thailand were administered to rats, and the enhancement of the in vitro phagocytic activity was assessed. The results showed that NPV potently enhanced antibody production and the phagocytic activity. Moreover, NPV-treated rats showed a reduction of edema in type 4 hypersensitivity reactions. The results indicated that NPV had immunomodulatory effects, and therefore, NPV could be considered a functional food.

Quantitative carbon distribution analysis of hydrocarbons, alcohols and carboxylic acids in a Fischer-Tropsch product from a Co/TiO2 catalyst during gas phase pilot plant operation

Comprehensive two-dimensional gas chromatography (GCxGC) analysis for 1-alcohols and gas chromatography–mass spectrometry (GC-MS) analysis for carboxylic acids, derivatised as their methyl esters, have been applied to liquid and wax Fischer-Tropsch (FT) hydrocarbon products. These methods in combination with conventional one-dimensional gas chromatography (GC) analysis of the aqueous, gaseous, liquid hydrocarbon and wax products plus conventional high-performance liquid chromatography (HPLC) analysis of the aqueous phase has allowed a quantitative distribution analysis of FT hydrocarbon and oxygenated products to be demonstrated for a Co/TiO2 catalyst operating in a fixed bed gas phase pilot plant utilising CANSTM catalyst carrier devices. The GC-MS method used is, to the best of our knowledge, the first application of this derivatisation route for the quantification of individual carboxylic acids in FT hydrocarbon product streams.Whilst the hydrocarbons and oxygenates that were identified are known compounds formed during the low temperature, Co catalysed, FT process the combination of the multiple analysis techniques used has allowed a level of detail to be gained on the product composition that is seldom reported.Additionally, 1H nuclear magnetic resonance spectroscopy (NMR) and 13C NMR analyses were used to quantify the average concentration of 1-olefin, cis- and trans-2-olefins, 1-alcohol and aldehyde as appropriate for the technique used. Comparison of GCxGC versus 1H NMR and GC-MS versus a KOH titration confirmed the applicability of the chromatographic methods for the quantitative analysis of FT oxygenated compounds. Long-chain 1-alcohols and carboxylic acids, ≥ C3, were found to be present at levels of 1/10th and 1/1000th that of hydrocarbons of equivalent carbon chain length respectively. The 1-olefin:n-paraffin ratio in the hydrocarbon liquid and wax products was found to decrease significantly with increasing carbon chain length and much more so than those of the 2-olefin or 1-alcohol.

Carboxylic acid recovery from Fischer\u2013Tropsch aqueous product by fractional freezing

About half of the product from iron-based high-temperature Fischer–Tropsch synthesis is an aqueous product containing dissolved oxygenates. Volatile oxygenates can be recovered by distillation, but the bulk of the carboxylic acids remain in the water, which is called acid water. Fractional freezing was explored as a process for producing a more concentrated carboxylic acid solution from which the carboxylic acids could be recovered as petrochemical products, while concomitantly producing a cleaner wastewater. Solid–liquid equilibrium data were collected for aqueous solutions of acetic acid, propionic acid, and butyric acid. A synthetic Fischer–Tropsch acid water mixture (0.70 wt% acetic acid, 0.15 wt% propionic acid, and 0.15 wt% butyric acid) was prepared and the liquid phase concentrations of the acid species at solid–liquid equilibrium were determined. Control experiments with material balance closure on each of the carboxylic acid species were performed at selected conditions. Having more than one carboxylic acid species present in the mixture meaningfully changed the solid–liquid equilibrium versus temperature of the system. The carboxylic acids partitioned between the solid phase and the liquid phase and a practical design would require multiple duty-controlled solid–liquid equilibrium stages, with most of the separation taking place in the temperature range 0 to − 5 °C.

Microbial ecology of a lactate-driven dark fermentation process producing hydrogen under carbohydrate-limiting conditions

Despite the high prevalence of lactic acid bacteria in dark fermentation (DF) processes, their ecological role is not yet completely elucidated, preventing their systematic use as “helpers” for hydrogen production. The aim of this study was to investigate the microbial community structure of a lactate-driven DF process that successfully produced hydrogen under carbohydrate-limiting conditions using tequila vinasse as a substrate. Microbial responses to stepwise decreases in hydraulic retention time (HRT) from 24 to 4 h were assessed by using Illumina MiSeq sequencing. HRTs above 12 h and below 6 h led to a lower hydrogen production rate (HPR; 0.2–3.3 L/L-d) and process stability (HPR variations within 25–65%), which were associated with the presence of Acetobacter lovaniensis, Clostridium luticellari, Blautia coccoides, and the high abundance of propionate and lactate. Interestingly, transient conditions from unsteady-to-steady state occurred at an HRT of 12 h, where species richness and evenness decreased remarkably. Accordingly, HRTs between 12 and 6 h resulted in higher HPRs of up to 11.7 ± 0.7 L/L-d with HPR variations of less than 10%, which closely matched with the dominance of Clostridium sp., and butyrate and acetate as the main aqueous products. Overall, the results indicate that the successfulness of exploiting the ‘unwanted’ LAB proliferation through lactate-driven DF processes requires the enrichment of lactate-consuming and hydrogen-producing bacteria, which entails the selection of proper biocatalysts and operating conditions/strategies such as the operation of DF reactors under carbohydrate-limiting conditions and low HRTs.

Effect of Relative Humidity on Secondary Brown Carbon Formation in Aqueous Droplets.

Atmospheric brown carbon (BrC) is a significant contributor to particulate light absorption. Reactions between small aldehydes and reduced nitrogen species have been shown to produce secondary BrC in atmospheric droplets. These reactions can be substantially accelerated upon droplet evaporation. Despite aqueous droplets undergoing continuous water evaporation and uptake in response to the surrounding relative humidity (RH), secondary BrC formation in these droplets under various RH conditions remains poorly understood. In this work, we investigate BrC formation from reactions of two aqueous-phase precursors, glyoxal and methylglyoxal, with ammonium sulfate or glycine in aqueous droplets after drying at a range of RH (30-90%). Our results illustrate, for the first time, that BrC production varies as a function of RH. For all four chemical reaction systems being investigated, mass absorption efficiencies (MAE, m2/g C) of aqueous aerosol products (from 270 to 512 nm wavelength range) generally increase with reducing RH to reach a maximum at ∼55-65% RH and subsequently decrease, caused by further drying. Chemical characterization using high-resolution aerosol mass spectrometry shows that the formation of nitrogen-containing organic species also follows a similar variation with RH. Our observations reveal that the acceleration of BrC production from evaporation of water may be diminished by other factors, such as limited particle-phase water content, phase transition, and volatility of reactants and products. Overall, our results highlight that intermediate RH conditions in the atmosphere may be more efficient in secondary BrC formation, indicating that the effect of RH needs to be included in atmospheric models for a more accurate representation of light-absorbing aerosol formation in aqueous droplets.

Optical and photocatalytic properties of ZnO and ZnS structures formed as controlled calcination products of l-cysteine assisted aqueous precipitation

ZnO and ZnS structures were obtained by the calcination of the aqueous precipitation products of Zn(NO3)2, NaOH and l-cysteine (Cys). Initial Cys:Zn molar ratios were changed as 0.1:1, 0.5:1, 1:1 and 1.5:1. All the precursors were transformed into ZnO upon calcination at 700 °C. ZnS structures were obtained by calcining the precursors prepared at the Cys:Zn ratios of 1 and 1.5 at 350 °C. In addition to changing chemical composition of the precipitation products, calcination temperature and initial Cys:Zn ratio also affected morphology, surface area, photoluminescence and photocatalytic properties of the final products. Free exciton energy values of the ZnO samples were observed to be between 3.29 eV and 3.35 eV. PL spectra of the ZnO samples indicated blue and green emission centers. Zinc interstitials (Zni), revealed by the blue emissions in the PL spectra were also confirmed by Auger Zn L3M4.5M4.5 spectra. The samples calcined at 350 °C removed rhodamine B mainly by adsorption. All the samples calcined at 700 °C successfully degraded the dye under UV light. Among the samples calcined at 700 °C, ZnO sample prepared at Cys:Zn = 0.5, which has the highest surface area and unique photoluminescence spectrum exhibited the fastest photodegradation rate.

Efficacy and safety of Huaier granules combined with chemotherapy for gastric cancer: A protocol for systematic review and meta-analysis.

Background:Huaier granules, the aqueous product of Huaier (Trametes robiniophila Murr.) extract, are a broad-spectrum anti-tumor drug and have been widely used for the treatment of gastric cancer (GC). The aim of this study is to systematically investigate the efficacy and safety of Huaier granules combined with chemotherapy in the treatment of GC.Methods:Three English databases and four Chinese databases will be searched from its inception to July 2020. Two methodological trained researchers will select the qualified studies for data extraction independently. Cochrane Risk of Bias tool will be used to assess the risk of bias of included studies. The RevMan 5.2 and stata 14.0 software will be applied for statistical analyses. Statistical heterogeneity will be computed by Cochrane X2 and I2 tests. Sensitivity analysis will be conducted to evaluate the stability of the results. The publication bias will be evaluated by funnel plots and Egger's test. The quality of evidence will be assessed by the GRADE system.Results:The results of our research will be published in a peer-reviewed journal.Conclusion:The conclusion of our systematic review will provide evidence to judge whether Huaier granules combined with chemotherapy is an effective intervention for patient with GC.OSF registration number:10.17605/OSF.IO/9BVJD.

Transformation of nitrogen during hydrothermal carbonization of sewage sludge: Effects of temperature and Na/Ca acetates addition

This study reports the effects of temperature and Ca/Na acetates addition on the transformation of nitrogen during hydrothermal carbonization of sewage sludge at 160–250 °C. The nitrogen species in the hydrochar, aqueous, oil and gas products from sludge hydrothermal carbonization at different temperatures are well characterized, with a focus on the amino acid species in various products. Temperature is found to greatly affect the nitrogen transformation during sludge hydrothermal carbonization. At 160 °C, 47.3% of nitrogen is transformed into the aqueous product. When the temperature increases to 250 °C, only 27.1% of nitrogen is retained in the hydrochar, while 69.2 and 6.7% of nitrogen is present in the aqueous and oil products, respectively. During hydrothermal carbonization, the protein-N is first converted into the polypeptide-N in the aqueous product, followed by its further decomposition into the NH+ 4-N. This leads to a high content of the NH+ 4-N in the aqueous product, especially at increased temperatures. The labile protein-N is also transformed into the heterocylic-N (especially the pyrrole-N) in the hydrochar as the temperature increases. Among all nitrogen species in the aqueous product, the polypeptide-N consisting of amino acids with the alkyl group is the most stable. Moreover, the addition of NaAc and CaAc2 reduces the nitrogen retention in the hydrochar, mainly due to enhanced hydrolysis of the protein-N. While for CaAc2 addition, the deamination of the polypeptide-N is also enhanced, leading to a higher NH+ 4-N in the aqueous product. Our results show that the type of amino acid in protein is important to determine the nitrogen transformation pathways, and acetate addition is an important strategy for enhancing nitrogen removal in the hydrochar during hydrothermal carbonization.

Beneficial effects of high-pressure homogenization on the dispersion stability of aqueous hydrolysate from Mytilus edulis

Owing to the formation of aggregation and gelation during storage, certain proteins and peptides exhibit limited applications in aqueous protein food products. The purpose of this study was to investigate the influence of homogenization and xanthan gum addition on the dispersion stability of Mytilus edulis hydrolysate (PHM). High-pressure homogenization (HPH) at 360 and 40 bar in the first and second values, respectively, and adding xanthan gum at a concentration of 1 mg/mL showed significantly improvement on the stability of the PHM solution. PHM-xanthan gum solutions (PHMX) showed the highest polypeptide precipitation rate and turbidity retention rate compared with those of PHM. Moreover, the centrifugal precipitation rate of PHMX without HPH was higher than that of homogeneous PHMX. After HPH treatment at 400 bar, the percentage of smaller particles in PHM and PHMX was increased, the aqueous system became more uniform, and the fluorescence intensity reached its maximum. HPH pre-treatment improved the polypeptide dispersion stability and turbidity retention rate of PHM and PHMX and reduced the fluorescence intensity. The interactions of xanthan gum and polypeptide render the network microstructure more uniform under the conditions of homogenization, thus improving the dispersion stability of PHMX solutions. Therefore, under the premise of adding xanthan gum, HPH can better enhance the dispersion stability of the polypeptide in PHM.

Effect of process wastewater recycling on the chemical evolution and formation mechanism of hydrochar from herbaceous biomass during hydrothermal carbonization

Hydrothermal carbonization (HTC) is a promising thermochemical method used to upgrade herbaceous biomass for high-grade fuel. However, the technique yields large amounts of organic process wastewater (PW), which must be properly disposed or reused. In this work, PW was used as water source to prepare HTC feedstock. The evolution of the chemical structure and formation mechanism of hydrochar over the course of four PW recycles were demonstrated by experimental determination of the chemical compositions, equilibrium moisture contents, carbon structures, functional groups, and micro morphologies of the biomass (cornstalk in this study) and resulting hydrochars. The chemical reaction pathways induced during the HTC of biomass was established on the basis of the evolution of the chemical characteristics of the hydrochars and organic components of PW. The results showed significant improvements in the fuel quality of hydrochar as the number of PW recycles increased. The higher heating value, mass yield, and energy recovery efficiency of the hydrochars increased to 23.31 MJ/kg, 62.16%, and 86.24%, respectively, after four PW recycles because PW recycling facilitates the conversion of biomass into a hydrochar matrix with a high carbonization degree and polymerization of intermediates into microspheres. As the number of PW recycles increased, the relative content of furan compounds in the aqueous product decreased and the content of aromatic compounds increased. Further analysis of the aqueous products revealed the polymerization of furfural and 5-hydroxymethylfurfural into aromatic compounds and inhibition of the direct polymerization of aldehydes into aromatic compounds. The results of this work provide a theoretical basis for studying the chemical reaction and evolution mechanism of herbaceous biomass during HTC with recycled PW.

Research status and trend of electrolytes in the CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; electrochemical reduction

The concentration of CO2 in the atmosphere increases with utilizing fossil energy, which caused serious environmental problems. Owing to the advantage of using renewable electricity, the issue of carbon recycling and energy recovery based on the electrochemical CO2 reduction reaction (CO2RR) presents a potentially sustainable way to transform CO2 into a variety of valuable products, such as carbon monoxide (CO), methanol (CH3OH), formic acid (HCOOH/HCOO−), and so on. The challenges of CO2RR mainly include high overpotential, low current density and low Faraday efficiency (FE). Therefore, the development of new electrochemical reduction systems to reduce overpotential and improve reaction selectivity is the research hotpot in CO2RR. The selection of the electrolyte is very important to design efficient electrochemical reduction systems, which provides the reaction environment, transports ions and serves a conductive medium in CO2RR system. Under the same condition, the species, concentration, and pH of electrolytes influence the local reaction environment, the current density and the selectivity of products. So far, various electrolytes, such as alkali metal and ionic liquid electrolytes have been applied to enhance the performance of CO2RR. Therefore, in comprehensive understanding of the electrolyte effects on CO2RR is crucial in selecting proper electrolytes for the reduction of CO2 to desired products. This paper mainly reviews the recent processes in the alkali metal and ionic liquid electrolytes, and summarizes their effects in CO2RR as well. Firstly, we summarize the product distribution and current density of CO2RR in the different alkali metal aqueous. Alkali metal aqueous is the most common solvent for CO2RR, because alkali metal aqueous are widely available at low cost, relatively easy to prepare, and store safely. Many studies reported that alkali metal aqueous effects CO2RR current density and product distribution. The effects of metal aqueous on the CO2RR based on preferential hydrolysis of hydrated cations near the cathode surface, which to buffer the electrolyte near the electrode surface, offsetting the polarization losses caused by concentration gradient. At the same time, hydrated alkali metal cations in the outer Helmholtz plane can create a dipole field, which can stabilize the adsorption the intermediates to enhance the selectivity of the CO2RR on the intrinsic activity. Secondly, ionic liquids as electrolytes have also attracted extensive interest due to their high electrical conductivity, high CO2 adsorption capacity, and high selectivity. Because the ionic liquid can be adsorption on the electrode surface to reduce the overpotential and change the reaction microenvironment. Using different ionic liquid electrolytes can promote CO2 electroreduction to different products, such as CO, HCOO−/HCOOH, CH3OH and so on, especially in the performance of production selectively. Although important progress has been made in CO2RR with ionic liquid electrolyte, the mechanism of CO2RR to C2+ products is unclear, especially the interaction between the liquid and the electrode surface. Finally, we briefly prospect the future research priorities and directions of CO2RR systems in ionic liquid electrolyte.

Atmospheric-Pressure Pulsed Discharge Plasma in a Slug Flow Reactor System for the Synthesis of Gold Nanoparticles.

Gold nanoparticle (AuNP) formation by applying pulsed discharge plasma in the slug flow reactor system was demonstrated. Experiments were carried out continuously at room temperature. The argon gas as a gas phase and the hydrogen tetrachloroaurate(III) tetra hydrate solution containing lysine as a liquid phase simultaneously flowed in the slug flow reactor system. The flow rates of the feed solution and argon gas were kept at 1.5 and 0.2 mL/min, respectively. To generate discharge plasma, the AC power supply with a bipolar pulsed output at 10 kV was applied. The purple color solution product was obtained, and the ultraviolet–visible (UV–vis) spectrophotometer showed that this possessed the absorption light from 510 to 550 nm associated with the existence of gold nanoparticles in each collected sample. Transmission electron microscopy (TEM) revealed that the lysine-capped AuNPs were produced in a spherical morphology and dispersed in aqueous solution products with a diameter of less than 20 nm.

Caleta el Cobre 022 Martian meteorite: Increasing nakhlite diversity

AbstractCaleta el Cobre (CeC) 022 is a Martian meteorite of the nakhlite group, showing an unbrecciated cumulate texture, composed mainly of clinopyroxene and olivine. Augite shows irregular core zoning, euhedral rims, and thin overgrowths enriched in Fe relative to the core. Low‐Ca pyroxene is found adjacent to olivine. Phenocrysts of Fe‐Ti oxides are titanomagnetite with exsolutions of ilmenite/ulvöspinel. Intercumulus material consists of both coarse plagioclase and fine‐grained mesostasis, comprising K‐feldspars, pyroxene, apatite, ilmenite, Fe‐Ti oxides, and silica. CeC 022 shows a high proportion of Martian aqueous alteration products (iddingsite) in olivine (45.1 vol% of olivine) and mesostasis. This meteorite is the youngest nakhlite with a distinct Sm/Nd crystallization age of 1.215 ± 0.067 Ga. Its ejection age of 11.8 ± 1.8 Ma is similar to other nakhlites. CeC 022 reveals contrasted cooling rates with similarities with faster cooled nakhlites, such as Northwest Africa (NWA) 817, NWA 5790, or Miller Range 03346 nakhlites: augite irregular cores, Fe‐rich overgrowths, fine‐grained K‐feldspars, quenched oxides, and high rare earth element content. CeC 022 also shares similarities with slower cooled nakhlites, including Nakhla and NWA 10153: pyroxene modal abundance, pyroxenes crystal size distribution, average pyroxene size, phenocryst mineral compositions, unzoned olivine, and abundant coarse plagioclase. Moreover, CeC 022 is the most magnetic nakhlite and represents an analog source lithology for the strong magnetization of the Martian crust. With its particular features, CeC 022 must originate from a previously unsampled sill or flow in the same volcanic system as the other nakhlites, increasing Martian sample diversity and our knowledge of nakhlites.

Treatment of municipal sludge by hydrothermal oxidation process with H2O2

The recent increase in municipal sludge worldwide has led to a great deal of interest in developing an efficient and environmentally friendly sludge treatment method. In the paper, the treatment of municipal sludge by hydrothermal oxidation (HTO) process with H2O2 as the oxidant was proposed. The impacts of HTO temperature and H2O2 mass fraction on the distribution of products, the moisture content, the migration behaviors of the heavy metals (HMs) of the resulted solid products, the concentration of volatile fatty acids (VFAs) and NH3–N contained in the resulted aqueous phase products and the pH value were investigated. The results indicated that the sludge reduction was achieved by HTO treatment, the increasing H2O2 mass fraction and HTO temperature can significantly improve the dewatering performance of the sludge. The potential toxicity fraction of Pb and Cd contained in the resulted solid residual increased with the increasing HTO severity and the potential toxicity fraction of solid residues was still lower than that of raw material. Acetic acid was the main VFAs produced from HTO treated sludge, and its concentration reached to the maximum value of 2923.41 mg/L at 230 °C under H2O2 mass fraction of 15%. The change in the pH of the resulted aqueous phase products was caused by the competition between the acidic (VFAs or CO2) or alkaline (NH3–N) substances derived from the sludge during HTO process. The HTO process was expected to be an efficient method for municipal sludge treatment due to its mild conditions and high heavy metal safety.

Insight into role and mechanism of Li on the key aspects of biodegradable ZnLi alloys: Microstructure evolution, mechanical properties, corrosion behavior and cytotoxicity.

ZnLi based alloys have been proved as desirable candidates for biodegradable materials accounting for its high mechanical performance and great biocompatibility. However, effects of Li on microstructure and comprehensive properties of Zn alloys are seldom investigated and need to be addressed. Herein, Zn-(0.1-1.4wt%)Li alloys are fabricated and systematically analyzed. Lath-like Zn precipitates are observed in the primary β-LiZn4 (β) phase of Zn-(0.5-1.4wt%)Li alloys, leading to the formation of dense β/Zn lamellar structure with an inter-spacing of 0.8μm. Mechanical tests show that the strengths of the ZnLi alloys have at least tripled due to the formation of dense β/Zn lamellar structure. Early degradation behaviors of the ZnLi alloys in simulated body fluid (SBF) reveal a competitive releasing of Li+ and Zn2+. As the priority of Li+ releasing becomes more obvious with increasing Li content in the alloys, aqueous insoluble Li-rich corrosion products containing LiOH and Li2CO3 form a passivation film on Zn-(0.5-1.4wt%)Li alloys. Consequently, corrosion rate decreases significantly from 45.76μm/y of pure Zn to 14.26μm/y of Zn-1.4Li alloy. Importantly, observations of white light interferometer microscope and transmission electron microscope demonstrate that β phase degrades prior to Zn in the alloys, suggesting that biomedical implants made of ZnLi alloys are likely to degrade completely in human body. Cytotoxicity tests of the alloys exhibit no cytotoxicity in 10% extracts. The most tolerated Zn2+/Li+ concentrations of the alloy extracts to L-929 cells are calculated, which provides guidance for future design of Zn alloys containing Li.