Addition Of HNO3 Research Articles

Reversible hydrogenation and dehydrogenation of benzene for hydrogen storage on highly dispersed Pd/γ-Al2O3 catalyst

The research and development of efficient catalyst is the key to achieving high-capacity hydrogen storage in liquid organic hydrogen carriers (LOHCs). The highly dispersed Pd/γ-Al2O3 catalysts with few-atom Pd were prepared by impregnation method using HNO3 as promoter. The hydrogen storage capacity of the benzene/cyclohexane hydrogen carriers was further investigated by vapor phase benzene hydrogenation and cyclohexane dehydrogenation reactions over the studied Pd/γ-Al2O3 catalysts. The results showed that the metal Pd was the active centers for the benzene hydrogenation/cyclohexane dehydrogenation reactions. The addition of HNO3 can effectively promote the metal Pd to be highly dispersed, thus improving the Pd atoms utilization and reducing the Pd dosage. Meanwhile, the strongly electronic effects between the highly dispersed Pd species and the Al2O3 support promoted the electron-deficient Pdδ+ sites to be formed, which enhanced the adsorption and activation ability for the reactants molecules. The benzene conversion on the Pd/γ-Al2O3 catalyst with a metallic Pd loading of 1.0 wt% reached 97.51 % at 200 °C. While the cyclohexane conversion reached 90.94 % at 400 °C with the actual hydrogen storage capacity of 6.54 wt%, which provided an effective idea for large-scale storage and transportation of H2 based on LOHCs.

Calcium-based polymers for suppression of soil acidification by improving acid-buffering capacity and inhibiting nitrification

Soil acidification is a major threat to agricultural sustainability in tropical and subtropical regions. Biodegradable and environmentally friendly materials, such as calcium lignosulfonate (CaLS), calcium poly(aspartic acid) (PASP-Ca), and calcium poly γ-glutamic acid (γ-PGA-Ca), are known to effectively ameliorate soil acidity. However, their effectiveness in inhibiting soil acidification has not been studied. This study aimed to evaluate the effect of CaLS, PASP-Ca, and γ-PGA-Ca on the resistance of soil toward acidification as directly and indirectly (i.e., via nitrification) caused by the application of HNO3 and urea, respectively. For comparison, Ca(OH)2 and lignin were used as the inorganic and organic controls, respectively. Among the materials, γ-PGA-Ca drove the substantial improvements in the pH buffering capacity (pHBC) of the soil and exhibited the greatest potential in inhibiting HNO3-induced soil acidification via protonation of carboxyl, complexing with Al3+, and cation exchange processes. Under acidification induced by urea, CaLS was the optimal one in inhibiting acidification and increasing exchangeable acidity during incubation. Furthermore, the sharp reduction in the population sizes of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) confirmed the inhibition of nitrification via CaLS application. Therefore, compared to improving soil pHBC, CaLS may play a more important role in suppressing indirect acidification. Overall, γ-PGA-Ca was superior to PASP-Ca and CaLS in enhancing the soil pHBC and the its resistance to acidification induced by HNO3 addition, whereas CaLS was the best at suppressing urea-driven soil acidification by inhibiting nitrification. In conclusion, these results provide a reference for inhibiting soil re-acidification in intensive agricultural systems.

Optimisation of extraction of valuable metals from waste LED via response surface method

AbstractThe valuable metals were separated and extracted from waste light-emitting diodes (LEDs) by pyrolysis and leaching process. About 98.16% Ga and 99.54% Y were recycled from the LEDs after the pyrolysis by sieving process in advance. The effects of various leaching conditions on the extraction of Fe, Cu and Ag were investigated by single factor experiments and response surface method. About 90.15% Fe was selectively extracted from the waste LEDs by H2SO4 leaching without oxidant, and 99.55% Cu and 99.36% Ag were recovered from the iron leaching residue by acid leaching with the addition of HNO3. The XRD and SEM−EDS analyses confirmed that the iron and copper were effectively extracted from the waste LEDs by the developed process.

Numerical investigation of methane seepage behaviour in coal with lattice Boltzmann approach: The synergistic effects of oxidizing acid and ionic liquid

Reagent modification is widely used in the coal industry to enhance the pore-fracture structures and seepage channel. Unfortunately, the investigations of methane seepage capacity in coal seams before and after reagent modification from a microscopic perspective were scarce. In this study, a novel lattice Boltzmann (LBM) – based methodology was developed to estimate the methane seepage capacity by incorporating the effects of oxidizing acid (nitrate acid, HNO3) and ionic liquid (1-butyl-3methylimidazole tetrafluoroborate, [Bmim][BF4]). The main conclusions are as follows: the addition of HNO3 and [Bmim][BF4] enhanced the pore structure, increased the maximum seepage velocity, but decreased the average flow velocity; and made the positions of higher cross-sectional velocity closer to the inlet of seepage channel. The reason is mainly attributed to the small cracks or pores adsorbed by [Bmim][BF4], which deteriorated the channel connectivity and slowed down the gas flow. With the increase of solid core distribution probability (Pc) value, the addition of HNO3 and [Bmim][BF4] benefitted the seepage channel more obviously, decreased the maximum seepage velocity more significantly, and declined the average seepage velocity more rapidly. This study can provide a theoretical guidance for the development of acidizing and infiltration enhancement technologies in coal seams.

Iron valence state evolution and hydrochar properties under hydrothermal carbonization of dyeing sludge

Iron (Fe) migration mechanisms and hydrochar properties in dyeing sludge hydrothermal carbonization (HTC) are important topics in wastewater treatment. HTC treatment of sludge produces wastewater containing Fe so it is necessary to study the migration behavior of Fe during HTC treatment. This study investigated the basic properties and Fe migration behavior of hydrochar during HTC treatment supplemented with nitric acid (HNO3). The results showed that the carbonization degree and yield of hydrochar treated with the HNO3 solution (HHC) were much lower than those of hydrochar treated with ultrapure water (WHC). The variation of total Fe (TF) concentration indicated that the decomposition of organic material and dissolution of minerals in the aqueous release of Fe during the liquid phase, led to much lower TF concentrations compared to the original dyeing sludge. Fe release was further enhanced with the addition of HNO3 and increase of temperature, rendering a much lower TF concentration of the HHC compared to the WHC. The variations of Fe3+ and Fe2+ concentrations indicated that the HTC-treated hydrochar contained more Fe2+, caused by Fe3+ reduction with hydroxyl methyl-furfural and glucose in the liquid and subsequent Fe2+/Fe3+ transferral to the solid hydrochar phase. X-ray diffraction (XRD) showed that the main Fe content in WHC was FeO(OH), while HHC contained mainly Fe(SO4)(OH)•2H2O and Fe3O4. XPS and XRF showed that Fe could more easily enter the internal pores of the hydrochar instead of being deposited on the surface. This study provided more insights on Fe migration behavior during HTC treatment.

Molecular dynamics and network analysis reveal the contrasting roles of polar solutes within organic phase amphiphile aggregation

Amphiphile self-assembly in non-polar media is often enhanced by polar co-solutes. This is observed within many biphasic separations processes, where amphiphiles mediate transport of water and acid into organic solution. A myriad of competitive intermolecular interactions have thus far prevented a fundamental understanding of the individual and dual roles of these polar solutes upon amphiphile self-assembly in non-polar media. Toward this end, the current work employs classical molecular dynamics and intermolecular network analyses to deconstruct the individual affects of water and nitric acid upon the self-assembly of N,N,N’,N’-tetraoctyl-3-oxapentanediamide (TODGA), a prevalent amphiphile extractant used in metal ion separations. In the absence of acid, and at low water concentration, H2O is found to promote local dimer and trimer formation of TODGA, however as [H2O]org increases, preferential self-solvation leads to large (H2O)n clusters that cause TODGA clusters to sorb to the (H2O)n periphery and supports extended aggregation. Addition of HNO3 to the humid solutions disrupts the water hydrogen bond network and inhibits the formation of large water clusters - thus preventing extended aggregation behavior and encouraging local aggregation. Prior experimental observations of enhanced TODGA self-assembly under these conditions are attributed primarily to the role of water rather than co-extracted HNO3, thus providing valuable new insight into the means by which extractant aggregation can be tuned within separations processes. The different roles of polar co-solutes, that derive from their individual hydrogen bonding capabilities and competitive interactions in the context of preferred solvation environments, is of fundamental importance amphiphile behavior in non-polar media.

Preparation and characterization of graphene oxide from coal

Herein, we report a facile method for the preparation of graphene oxide from semi-bituminous coal. Ultrafine powdery (∼72 mesh) demineralized coal was treated with concentrated H2SO4 in presence of NaNO2 in an ultra-sonication system at 80 °C for 24 h followed by the addition of HNO3 to obtain the desired graphene oxide product. The synthesized material was characterized by Raman spectroscopy, XRD, XPS, FTIR, UV–vis spectroscopy, and Zeta potential analyzer. The Raman spectra of the synthesized product show two peaks at 1350 cm−1 and 1590 cm−1, corresponding to the D band and G band, respectively with an ID/IG value of about 1.04. C1s XPS data of synthesized material showed three peaks at 284.46 eV, 286.28 eV, and 289.35 eV corresponding to the presence of C-sp2 carbon, epoxide group, and carboxyl group respectively with the carbon percentage of 64% and the oxygen percentage of 26%. FTIR spectrum of the synthesized material showed a broad peak at 3428 cm−1 corresponding to the stretching mode of the O–H bond and a peak at 1626 cm−1 corresponding to the stretching and bending vibration of water molecules adsorbed on the material. SEM images of the synthesized material show distinct edges, wrinkled surfaces, stacked and layered structures compared to the coal. All the observed results indicate the formation of graphene oxide.

Ion-selective electrode-based potentiometric immunoassays for the quantitative monitoring of alpha-fetoprotein by coupling rolling cycle amplification with silver nanoclusters.

Potentiometric immunoassays have been utilized for the quantitative detection of alpha-fetoprotein (AFP) in hepatocellular carcinoma, but most of them involve low sensitivity and enzyme labels, and thus are unfavorable for routine use. In this work, we report the proof-of-concept of a sensitive and powerful ion-selective potentiometric sensing method for AFP detection with an in situ amplified signal readout. This potentiometric immunoassay mainly contains a silver nanocluster-functionalized single-stranded DNA (AgNC-DNA), a short DNA primer and two antibodies. A sandwich-type immunoreaction is employed for AFP determination on an anti-AFP capture antibody-coated microplate using a biotinylated human AFP secondary antibody. Coupling with a typical biotin-avidin system, the biotinylated DNA initiator strands are conjugated on the microplate in the presence of AFP to induce the rolling cycle amplification (RCA) reaction, followed by AgNC-DNA hybridization. Upon addition of HNO3, the hybridized AgNCs are dissolved into numerous Ag(I) ions, which can be readily determined on a portable handheld silver-ion selective electrode (Ag-ISE). Under optimal conditions, the electrode potential increases with an increase in AFP concentration and exhibits a good linear range of 0.01-100 ng mL-1 at a detection limit of 7.9 pg mL-1. Moreover, the Ag-ISE-based potentiometric immune assay also shows good reproducibility, high specificity and long-term storage stability. Importantly, 18 human serum specimens containing the AFP analyte are screened using the potentiometric immunoassay, giving well-matched experimental results relative to the referenced enzyme-linked immunosorbent assay (ELISA) method.

BiOCl microspheres with controllable oxygen vacancies: Synthesis and their enhanced photocatalytic performance

The BiOCl microspheres consisted of nanosheets were synthesized at room temperature. It is demonstrated that the concentration of oxygen vacancies (OVs) in BiOCl can be controllable by modulating H+ concentration. The as-prepared BiOCl were further utilized in photocatalytic degradation of Rhodamine B (RhB) and Ciprofloxacin (CIP). Benefiting from the oxygen vacancies, BiOCl with rich OVs exhibited a superior photocatalytic activity than poor-BiOCl with few OVs prepared without addition of HNO3. Furthermore, of the obtained BiOCl microspheres, the BiOCl with 13.6% OVs showed the best photocatalytic property. And the rate constant for degradation of RhB and CIP were 0.834 min−1 and 0.018min−1, which are 1.7 and 1.6 times than poor-BiOCl. It is indicated that the optimized OVs concentration could capture photo-generated electrons most efficiently, which could improve the carrier migration rate. This work elevated the photocatalytic performance of BiOCl without the need for additional compound, which opens up a new avenues for design of highly efficient catalyst.

Spectrophotometric study of Solvent extraction of Pb (II) and Cd (II) by aminooctyldiphosphonic acid

This study has investigated the solvent extraction of cadmium and lead ions from an aqueous solution in nitrate medium using aminooctyldiphosphonic acid (AODPA) as extractant in chloroform. In order to establish spectrophotometrically the concentration of metal ion in the aqueous phase before and after extraction, the Arsenazo III method was used. The effects of several extraction parameters on the extraction of these metals ions including volume ratio between the aqueous and organic phases (1–5), extraction kinetic time (0–30 min), molar ratio Q (1–5), addition of HNO3 (pH =2–6), addition of KNO3 (0.01 – 1M), temperature (10–40°C) and the synergetic effect by adding TOPO (solvating agent) were evaluated. Thermodynamic parameters including the Gibbs free energy (ΔG0),enthalpy (ΔH0), and entropy (ΔS0) were calculated. Performed experiments showed that Pb (II) can be extracted till 73% when Cd (II) can be recovered completely after two cycles. The extraction of both metallic ions was spontaneous, endothermic and with a slight randomness. Positive synergetic effect was observed at a chelating agent/TOPO ratio of 3. It is a very encouraging result which can lead us to recover cadmium and lower the concentration of lead from wastewater.

Efficiency of water treatment with crushed shell of jatobá-do-cerrado (Hymenaea stigonocarpa) fruit to adsorb Cu(II) and Ni(II) ions: experimental and quantum chemical assessment of the complexation process.

The shell surrounding fruits of the jatobá-do-cerrado tree, in its natural state, was modified by the addition of HNO3 and NaOH and used as an adsorbent in the removal of Cu(II) and Ni(II) from aqueous solutions. The untreated (JIN) and chemically modified (JCT) fruit shell samples were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction. Their efficiency as adsorbents in the removal of Cu(II) and Ni(II) ions from aqueous solutions was studied under different conditions of pH (2-9) and it was observed that the optimal pH for Cu (II) adsorption was 5.5 and for Ni (II) it was 6.0. The adsorption isotherms were obtained at different temperatures (298, 308, 318 K) and the qmax values ranged from 33.96 to 41.00 mg g-1. The adsorbents presented higher selectivity toward Cu ions (II). The thermodynamic analysis results suggest that the adsorption process studied is of a physical nature. Supported by quantum mechanical calculations, the interaction sites of the ion-cellulose and ion-lignin complexes were identified, evidencing the central role of water molecules in stabilization of the complexes. The experimental and theorical results indicate that JIN and JCT have good potential for the adsorption of Cu(II) and Ni(II) ions and are thus promising materials for the removal of other metal ions in aqueous systems.

Effect of pretreatment on the ethanol and fusel alcohol production during fermentation of sugarcane press-mud

Diminishing fusel alcohol content on bioethanol streams is a challenge that must be overcome to increase hydrogen (H2) yield by ethanol steam reforming (ESR). Herein, a split plot experimental design was used to assess the effect of temperature and HNO3 loadings, during the pretreatment of sugarcane press-mud for subsequent fermentation, over both ethanol and fusel alcohol content. Results showed that pretreatment temperature has an important effect on ethanol concentration during fermentation owing to the formation of reducing sugar during pretreatment. The highest both ethanol (64 g L−1) and fusel alcohol (547 mg L−1) content were obtained at 130 °C without HNO3. But, at 130 °C, the addition of 16 g HNO3 kg−1 solid reduced the ethanol and fusel alcohol concentrations by 3.5 % and 20 %, respectively. Therefore, HNO3 did have an important effect on the fusel alcohol production, but a small effect on the ethanol concentration after fermentation. Under said pretreatment conditions (i.e., 130 °C and 16 g HNO3 kg−1 solid), a possible production of 5.46 g H2 kg−1 of sugarcane press-mud was calculated from mass balance and empirical correlations. Therefore, the addition of HNO3 during biomass pretreatment could enhance further H2 production by ESR.

A Study on the Effect of pH Value of Impregnation Solution in Nickel Catalyst Preparation for Methane Dry Reforming Reaction

AbstractThe nickel particle size, distribution and interaction with support are crucial to the catalytic performance in dry reforming of methane reaction (DRM). Despite numerous literatures on dry reforming catalysis, the effect of solution pH on the catalytic performance is not well studied. Herein, we designed a series of Ni/SiO2 catalysts with different Ni particle sizes. The Ni particle size was controlled with altering the pH of the Ni nitrate solution via the addition of HNO3 or NH4OH. X‐ray diffraction (XRD) revealed that NH4OH promoted Ni/SiO2 catalysts present smaller NiO nanoparticles, and enhanced metal‐support interaction was evidenced from X‐ray photoelectron spectra (XPS) and H2 temperature‐programmed reduction (H2‐TPR) analyses. In addition, according to thermogravimetric analysis and differential scanning calorimetry (TG‐DSC) and transmission electron microscopy (TEM) results, the spent catalysts produced less carbon deposition and maintained Ni nanoparticles in smaller size after DRM reaction. Catalysts with nearly uniform and small particle size demonstrated a satisfying resistance to aggregation and carbon deposition, while realizing a high CH4, CO2 and Ctotal conversion (74.5, 83.7 and 79.7%, respectively). The present study provides a simple but effective way to change the metal‐support interaction and metal particle size.

Antimicrobial, starch based barrier coatings prepared using mixed silver/sodium exchanged bentonite

The effect of silver nitrate concentration, pre-washed bentonite (to remove extraneous salt) and back-exchange procedures have been explored to assess the type of silver species formed and their behaviour upon exposure to further salts. X-ray fluorescence was used to quantify the amount of silver present and whether in cation exchange sites, whereas X-ray diffraction and transmission electron microscopy identified the silver compounds present.A further objective was to assess the antimicrobial, barrier and dispersion properties of the silver/sodium bentonites when incorporated into a starch-plasticiser-clay coating used for packaging. The silver/sodium bentonites demonstrated very strong antimicrobial activity towards Escherichia coli, Kocuria rhizophila and Aspergillus niger. Incorporating just 0.03 wt% of silver/sodium bentonite in the coating (0.2 μmol/m2 Ag in dried coating with thickness of 14 μm) produced a > 4.4 log reduction against an initial loading of 2.1 × 105 CFU/object for E. coli. Water vapour barrier properties of coatings prepared on paper and containing the mixed silver/sodium bentonite were unaffected since water vapour transmission rate values of ~20–40 g/m2.day (23°C, 50% relative humidity) were maintained. Also the presence of silver did not adversely affect the clay dispersion. The Ag+ release profile from mixed silver/sodium clay upon addition of HNO3 and NaNO3 is discussed.

Investigation of the conditions for selenium determination by photochemical vapor generation coupled to graphite furnace atomic absorption spectrometry

In this study instrumental parameters and sample preparation methods for Se determination using photochemical vapor generation (PVG) coupled to graphite furnace atomic absorption spectrometry (GF AAS) were investigated. Coconut water was selected as sample due to its nutritional importance and matrix complexity. The PVG was performed in a flow injection mode. The Se volatile species, generated in the UV reactor, were separated from the condensed phase in a gas-liquid separator and introduced automatically in the graphite furnace. These species were trapped on the integrated graphite platform surface coated with Ir as permanent modifier. The PVG conditions such as concentration of low molecular weight organic compound (LMWC), sample and carrier gas flow rate, effect of reagents frequently used in sample preparation (HNO3 and H2O2) were investigated. Formic acid 0.44 mol L−1 was selected as LMWC. The addition of HNO3 (14 mmol L−1) and H2O2 (145 mmol L−1) increased the sensitivity. Pre-reduction of Se (VI) to Se (IV) was performed on-line in a quartz spiral tube coated with a thin film of TiO2. The insertion of Ar flow rate (115 mL min−1) before the reactor inlet has improved the sensitivity, comparing with the introduction of Ar after the reactor. UV-assisted photo-oxidation of coconut water samples was employed as an alternative sample preparation to avoid the NO3−/NO2−, and H2O2 interference. The figures of merit were: sensitivity 0.0680 s ng−1, limits of detection and quantification 0.65 μg L−1 and 2.2 μg L−1, respectively, and characteristic mass of 62 pg. The PVG efficiency was estimated as 79% when comparing with conventional hydride generation. Furthermore, a mass balance study was accomplished in order to identify possible analyte losses in the PVG system, which the overall recovery was up to 85%. The results of recovery tests accomplished with real samples of coconut waters varied between 80 and 103% for Se (IV), Se (VI), and selenomethionine.

Template-free hydrothermal synthesis of 3D hollow aggregate spherical structure WO3 nano-plates and photocatalytic properties

A new kind of 3D hollow aggregate spherical structure WO3 nano-plates was prepared via a simple hydrothermal synthesis without any template. In this paper, the effects of HNO3 addition on the preparation of WO3 powder were systematically investigated. With HNO3 concentration increasing, the product was converted from WO3(H2O)0.33 to monoclinic WO3·H2O until the reaction to complete. Meanwhile, the morphology and size of particles changed from mocro-scale spheres to nano-plates. In the WO3·H2O structure, H2O integrates the H2O molecules via hydrogen bond, while WO3 bonds with other WO3 molecules and finally form a hollow spherical structure. During subsequent drying, WO3·H2O is deprived of crystal water to become monoclinic WO3, remaining this porous spherical structure. Compared with the industry-use catalyst of Degussa P25 TiO2, the as-prepared WO3 exhibits the wonderful photocatalytic activity due to the plate-like morphology and porous structure.

Multi‐crystalline silicon solar cells with metal‐assisted nano‐texturing using HNO3 as hole injection agent

In this study, metal‐assisted etching (MAE) with nitric acid (HNO3) as a hole injecting agent has been employed to texture multi‐crystalline silicon wafers. It was previously proven that addition of HNO3 enabled control of surface texturing so as to form nano‐cone shaped structures rather than nanowires. The process parameters optimized for optically efficient texturing have been applied to multi‐crystalline wafers. Fabrication of p‐type Al:BSF cells have been carried out on textured samples with thermal SiO2/PECVD‐SiNx stack passivation and screen printed metallization. Firing process has been optimized in order to obtain the best contact formation. Finally, jsc enhancement of 0.9 mA/cm2 and 0.6% absolute increase in the efficiency have been achieved. This proves that the optimized MAE texture process can be successfully used in multi‐crystalline wafer texturing with standard passivation methods. J –V curves and SEM images of the nano and iso‐textured samples. jsc enhancement of 0.9 mA/cm2 together with 0.6% absolute efficiency gain was observed on nano‐textured samples.magnified imageJ –V curves and SEM images of the nano and iso‐textured samples. jsc enhancement of 0.9 mA/cm2 together with 0.6% absolute efficiency gain was observed on nano‐textured samples.

Sensitive Bioanalysis Based on in-Situ Droplet Anodic Stripping Voltammetric Detection of CdS Quantum Dots Label after Enhanced Cathodic Preconcentration.

We report a protocol of CdS-labeled sandwich-type amperometric bioanalysis with high sensitivity, on the basis of simultaneous chemical-dissolution/cathodic-enrichment of the CdS quantum dot biolabel and anodic stripping voltammetry (ASV) detection of Cd directly on the bioelectrode. We added a microliter droplet of 0.1 M aqueous HNO3 to dissolve CdS on the bioelectrode and simultaneously achieved the potentiostatic cathodic preconcentration of Cd by starting the potentiostatic operation before HNO3 addition, which can largely increase the ASV signal. Our protocol was used for immunoanalysis and aptamer-based bioanalysis of several proteins, giving limits of detection of 4.5 fg·mL−1 for human immunoglobulin G, 3.0 fg·mL−1 for human carcinoembryonic antigen (CEA), 4.9 fg·mL−1 for human α-fetoprotein (AFP), and 0.9 fM for thrombin, which are better than many reported results. The simultaneous and sensitive analysis of CEA and AFP at two screen-printed carbon electrodes was also conducted by our protocol.

Influence of Various Acids Added to Irrigation Water on the Reduction of Bicarbonate Injury during Vegetative Propagation of ‘Seolhyang’ Strawberry

고농도 중탄산 피해경감을 위한 관개수의 산 혼합이 ‘설향’ 딸기의 영양생장에 미치는 영향을 구명하기 위한 목적으로 본 연구를 수행하였다, 연구목적을 달성하기 위해 중탄산(HCO3-)농도가 240mg·L-1 또는 90mg·L-1인 Hoagland 용액을 조제하여 –대조구와 +대조구로 삼고, –대조구에 질산, 인산, 황산, 질산+인산, 및 살리실산을 혼합하여 중탄산 농도를 60mg·L-1으로 낮춘 처리용액을 만들었다. 이후 3엽기인 ‘설향’ 딸기를 정식하여 모주로 삼고 126일 동안 처리하면서 모주 생육과 자묘의 발생 및 생장에 미치는 영향을 조사하였다. 모주의 생체중은 –대조구가 관개수에 산을 혼합한 모든 처리나 +대조구 보다 가벼웠다. –대조구에서 모주당 발생한 자묘수는 13.0개였지만, 질산, 인산, 황산, 질산+인산 및 살리실산 처리구는 각각 19.4, 20.1, 18.6, 22.4, 및 18.9 개체였다. 산을 처리한 경우 –대조구에 비해 발생한 자묘수가 뚜렷하게 많았으며, 특히 질산+인산 처리가 다른 처리들 보다 유의하게 자묘수가 많았다. –대조구와 살리실산 처리구에서 처리 126일 후 근권부의 pH가 각각 8.2와 7.3으로 상승하였지만, 질산, 인산, 황산 및 질산+인산 처리구는 각각 5.5, 5.4, 5.3 및 5.5로 측정되었다. 수확 후 식물체내 Ca 및 Mg 함량은 +대조구, 질산, 인산, 황산, 질산+인산, 살리실산 처리구에서 유사하였지만, –대조구에서 가장 적게 분석되었다. 식물체내 Fe, Mn, Zn, 및 Cu의 함량은 산을 혼합한 처리구에서 비슷했고, –대조구에서는 가장 적었다. 이상의 결과는 관개수에 고농도의 중탄산이 존재하여 피해가 발생할 때 다양한 산을 처리하여 피해를 경감시킬 수 있으며 특히 질산+인산 처리가 영양번식 중인 ‘설향’ 딸기생장 및 자묘 발생에 효과적임을 나타낸다.

Reactivity enhancement of calcium based sorbents by doped with metal oxides through the sol–gel process

The calcium-based sorbents are considered to be promising candidates for capturing CO2 from fossil fuel power plants and how to improve the CO2 capture and sintering-resistant performance of the sorbents during the cycling is a challenge for researchers. To improve the CO2 capture capacity and sintering resistant of the sorbents, CaO sorbents were synthesized by the sol–gel process with different precursors. Test matrices considering the important factors, such as dopant, doping amount, HNO3 addition and water addition in solvent were designed to investigate effects of synthesis conditions on reactivity of sorbents and to obtain an appropriate process for synthesizing sorbents for CO2 capture. The structural properties of the resulting sorbents were characterized by N2 physisorption and X-ray diffraction (XRD) techniques, showing that the sorbents prepared by the sol–gel process possessed wonderful microstructure as well as uniform distribution of CaO and MgO, MnO2 and TiO2. These features result in excellent reactivity enhancement and strong sintering resistant of sorbents compared with pure CaO, which give rise to high carbonation conversion, especially for CaO sorbents doped with MgO and MnO2, of 0.79 and 0.76 after 50 cycles under severe calcination condition, respectively. It demonstrates the excellent performance of sorbents synthesized by the sol–gel process.