Added Metal Ions Research Articles

The Effect of Divalent Metal Ions and Recycle Ratio of UASB Reactor on the Formation of Anammox Granules and Its Treatment Performance

The setting-up of anammox granules reactor is time-consuming and highly sensitive to the environment. Metal ions were reported to facilitate granulation; however, there is no report of a practical guide to metal ion application in anammox, especially relative to the effects of different ions at different concentrations on granulation. Adding recycle to reactors is important in treating industrial wastewater with high levels of NH4 +-N, but the optimum recycle ratio is still unclear. This study investigated the effect of Ca, Mg, Fe ions, their concentration, and recycle ratio of an upflow anaerobic sludge blanket reactor on anammox granulation as well as on reactor performance. The main physical properties of granules tested were sludge granulation rate, settling velocity, mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids/MLSS, and specific anammox activity (SAA)/nitrogen removal rate. The results demonstrated that introducing cations into cultivating mediums accelerates the anaerobic granulation process and improves specific anammox activity. In particular, Mg and Fe runs reached maximum SAAs with concentrations of 0.06 mmol/L and improved by ~ 25% of SAA compared with the control. SAAs of Ca runs were lower than those of Mg and Fe runs and showed a peak at a concentration of 0.03 mmol/L. In addition, recirculation enhanced the granulation. Granulation and retention of the anammox biomass were benefitted most when the recycle flow added was equal to the influent injection (noted as Q). Nitrogen removal also reached a maximum at Q, with removal efficiency of 97.3% with NH4 +-N and 98% with NO2 −-N. Thus, appropriately adding metal ions and recycle flow helped achieve quick setting-up and better performance. We also considered the relationship between four properties of granules tested and the performance of the reactor.

Metal-organic framework as luminescence turn-on sensor for selective detection of metal ions: Absorbance caused enhancement mechanism

The luminescence turn-on sensors are more suitable for the practical applications, because they can effectively avoid the wrong response and have a higher signal-to-noise in dark background, compared to the luminescent quenching probes. In this work, we use IRMOF-3 as a luminescent probe to systematically investigate its sensing behavior for detecting metal ions. By examining the relationship of absorbance and luminescent intensity of IRMOF-3 before and after adding metal ions, we propose a novel luminescence turn-on mechanism, i.e., absorbance caused enhancement (ACE) mechanism, to reveal the luminescence turn-on phenomena of IRMOF-3 for selectively sensing M3+ (Cr3+, Al3+, Ga3+, In3+) metal ions. By exploring the effects of M3+ ion concentrations on absorbance and luminescent intensity, we further confirm the ACE mechanism responsible for luminescence turn-on phenomena. The subsequent experimental results indicate that IRMOF-3 exhibits not only high sensitivity and anti-interference ability against M2+ and M+ metal ions, but also have excellent reusability and stability. In short, the ACE mechanism provides a possible strategy for designing luminescence turn-on probes.

Study on the effects of ionization seeds on pulse detonation characteristics

Ionization phenomenon is happened on the wave front due to the presence of high temperature and pressure in the detonation process. Plasma produced in the detonation process can be used as magnetohydrodynamic (MHD) generator or flow controlled by the external magnetic field. However, it is necessary to increase the ionization efficiency by adding metal ions with lower ionization potential owing to the limited amount of plasma produced by detonation. In this paper, a model of pulse detonation engine with ionization seeds was established. The Conservation Element and Solution Element (CE/SE) method was deduced to simulate the interaction between plasma and detonation process. The influence of ionization seed contents on the electrical conductivity and detonation characteristic parameters was analyzed, and the MHD control of detonation process was realized by adding the external electromagnetic field device. The results showed that it had a little influence on the detonation process but a great influence on the generation of detonation plasma by the addition of a certain amount of ionized seed. The ion mass fraction and electrical conductivity in the detonation tube were first increased and then decreased with the increase of ionization seed content, which reached the maximum at the ionization seed mass fraction of 0.05. The acceleration and deceleration process could be achieved by the MHD control.

Optimization of Natural Dye Extracted from Phytolaccaceae Berries and Its Mordant Dyeing Properties on Natural Silk Fabric

ABSTRACTA moderate approach was used to extract natural dye from wild Phytolaccaceae berries, and the stability and dyeing properties on the silk fabric of the exacted Phytolaccaceae natural dye was investigated. Via stability analysis, the natural dye had excellent stability during heating, pH or adding Metal ions. When the dyeing temperature was 30ºC, the K/S value of the dyed silk fabric was 6.3, and with SnCl2 mordant, the K/S value was increased 14.3%. The rubbing and washing fastness via metal mordant were increased by 0.5–1.5 grade compared to the fastness of fabric treated with direct dyeing method.

Facile synthesis and properties of the chemo-reversible and highly tunable metallogels based on polydicyclopentadiene

We report our study on the facile synthesis of reversible metallogels (metal coordinated polymer network) with tunable crosslinking density and metal ions, and the properties of the metallogels. The metallogels were prepared via non-covalent metal coordination crosslinking of functionalized soluble polydicyclopentadiene (sPDCPD). sPDCPD was first synthesized by ring-opening metathesis polymerization (ROMP) and functionalized using 3,6-di-2- pyridinyl-1,2,4,5-tetrazine (DPTZ) via the inverse electron-demand Diels-Alder (iEDDA) reaction. The structures of the synthesized macromolecular ligands DPTZ-sPDCPD were characterized by size-exclusion chromatography (SEC), Fourier transfer infrared spectroscopy (FITR) and nuclear magnetic resonance (NMR). Subsequently, DPTZ-sPDCPD was crosslinked by adding metal ions, e.g., Zinc or Nickel salts. Using the series of metallogels prepared, we investigated the effects of crosslinking densities, metal ion types, solvent types and polymer concentrations on the rheological properties of the prepared metallogels. We also demonstrated the excellent reversibility of the metallogel via repeated reclamation of the macromolecular ligands and metal coordination.

Biochemical characterization of aminopeptidase N2 from Toxoplasma gondii.

Aminopeptidase N (APN) is a member of the highly conserved M1 family of metalloproteases, and is considered to be a valuable target for the treatment of a variety of diseases, e.g., cancer, malaria, and coccidiosis. In this study, we identified an APN gene (TgAPN2) in the Toxoplasma gondii genome, and performed a biochemical characterization of the recombinant TgAPN2 (rTgAPN2) protein. Active rTgAPN2 was first produced and purified in Escherichia coli. The catalytic activity of the enzyme was verified using a specific fluorescent substrate, H-Ala-MCA; the rTgAPN2 was relatively active in the absence of added metal ions. The addition of some metal ions, especially Zn2+, inhibited the activity of the recombinant enzyme. The activity of rTgAPN2 was reduced in the presence of the EDTA chelator in the absence of added metal ions. The optimum pH for enzyme activity was 8.0; the enzyme was active in the 3–10 pH range. The substrate preference of rTgAPN2 was evaluated. The enzyme showed a preference for substrates containing N-terminal Ala and Arg residues. Finally, bestatin and amastatin were shown to inhibit the activity of the enzyme. In conclusion, rTgAPN2 shared general characteristics with the M1 family of aminopeptidases but also had some unique characteristics. This provides a basis for the function of aminopeptidases and the study of drug targets.

Optimization of lychee wine fermentation process using response surface methodology to reduce acetic acid content

Abstract: Acetic acid is the main component of the volatile acid in the wine. However, excessive amounts of acetic acid negatively affect wine quality. The study aimed to decrease acetic acid content produced by Saccharomyces cerevisiae fermentation after adding metal ion at different temperatures. Response surface methodology (RSM) was used to predict the optimum conditions for acetic acid removal. A central composite design was employed for the experiments and results were analyzed to obtain the best possible combination of fermentation temperature (X1: 16°C-24°C) and concentrations of potassium (X2: 0-12.0 mM), magnesium (X3: 0-8.0 mM), and calcium ions (X4: 0-0.2 mM) that would generate the minimum acetic acid in lychee wine at an initial acetic acid concentration of 1.5 g/L. Experimental data were fitted to a second-order polynomial equation using multiple regression analysis and analyzed using analysis of variance (ANOVA). During fermentation under pre-established conditions, the correlation coefficients R2 and Adj-R2 of the models for acetic acid removal were 0.9487 and 0.9007, respectively. After testing, the optimum conditions for acetic acid removal were determined as follows: fermentation temperature of 20°C; potassium, magnesium, and calcium ion concentrations of 10.1 mM, 6.1 mM, and 0.2 mM, respectively. The experimental acetic acid content of lychee wine under optimal conditions was found to be 0.309 g/L, which agreed well with the model-predicted value of 0.314 g/L. Keywords: lychee wine, acetic acid, fermentation, Saccharomyces cerevisiae, metal ion, response surface methodology DOI: 10.3965/j.ijabe.20160906.2270 Citation: Wu R N, Zhu P, Shang Y H, Zhong Q P. Optimization of lychee wine fermentation process using response surface methodology to reduce acetic acid content. Int J Agric & Biol Eng, 2016; 9(6): 223－230.

SYNTHESIS, CHARACTERIZATION, AND CHEMOSENSING APPLICATION OF POLY(METHYL METHACRYLATE-CO-HYDROXYETHYL METHACRYLATE) WITH DANSYL SIDE GROUP

A novel dansyl side-functional polymer ( P2 ) was prepared and employed as the metal cation sensing chemical probe. The synthesis of P2 was performed via free radical polymerization and esterification reactions in a two-step reaction sequence. P2 showed characteristic UV-vis and fluorescence emission bands for the dansyl unit. The fluorescence emission intensity of P2 gradually decreased as the concentrations of the added metal ions were increased. The highest quenching efficiencies (QE) were observed for Pb 2+ (84.56%) and Co 2+ (83.69%). Besides, the responses of P2 to the addition of Pb 2+ cation were quite linear up to 50 equivalent. The presence of Cd 2+ , Hg 2+ , Mn 2+ , and Zn 2+ cations did not pose significant interferences. Thus, P2 is a potential candidate for the fluorescence chemical sensor for Pb 2+ cation.

Effect of metal ions on the steam gasification performance of demineralized Shengli lignite char

Lignite is considered to be a promising coal to obtain H2 or H2-rich synthesis gas. In order to investigate which metal ions promote its high H2 production, Shengli lignite after partial demineralization followed by addition metal ions were mainly studied. The steam gasification reaction with temperature programmed was tested by using fixed-bed reactor. XRD, Raman, XPS and FTIR were used to do the research on microcrystalline structure changes of the Shengli lignite. The results proved that the gasification reactivity of HCl treatment samples were poor. The addition of alkali metal and alkaline earth metal had a distinguished catalytic effect on the steam gasification. Nevertheless, transition metal had a slight catalysis. The metal ions added into the acid treatment lignite decreased initiating gasification temperatures, increased H2 cumulative yield and H2/CO ratio in the syngas from the steam gasification, especially for Ca, K and Na. The XRD and Raman results revealed that the addition of alkali metal and alkaline earth metal made the char structure disorderly, and hindered chemical structure of coal changes towards graphitization. The XPS results indicated that the content of CO increased significantly after adding metal ions, which could contribute to opening the loop of aromatic nucleus. The reaction mechanisms about how metal ions catalyzed low-rank coals in steam gasification were proposed.

Surface Charge Control of Quantum Dot Blinking

A characteristic property of colloidal semiconductor nanocrystal quantum dots (QDs) is their emission intermittency. Although a unifying theory of QD photoprocesses remains elusive, the importance of charged states is clear. We now report a new approach to directly study the role of surface charge on QD emission by adding metal ions to individual, core-only QDs immobilized in aqueous solution in an agarose gel. The CdTe QDs show very stable emission in the absence of metal ions but a dramatic and reversible increase in blinking due to the presence of trivalent metal ions. Our results support a charge-separation model, in which the major blinking pathway is the surface trapping of electrons; transiently bound metal ions close to the QD surface enhance this process.

Luminescence Quenching and Enhancement by Adsorbed Metal Ions with Ruthenium Diimine Complexes Immobilized on Silica Polyamine Composites.

Luminescent ruthenium diimine complexes have been covalently bound to the surface of a silica polyamine composite (SPC) using peptide coupling agents. The loading of the complexes using this route is quite low (~0.01-0.04 mmol/g) leaving sufficient surface amines to coordinate added metal ions. When the composite particles containing the Ru complexes are exposed to solutions of Cu2+, Ni2+ or Zn2+, luminescence is quenched with efficiencies that follow concentration dependence and the relative binding affinities of the ions. When heavy metal ions such as mercury or lead are adsorbed onto the same surface, luminescence is enhanced by a factor of ~3.5. When the complexes are exposed to these metals in solution, no quenching or enhancement is observed. Both phenomena were shown to be the result of adsorption of the cations onto the polyamine surface by using the Stern-Volmer relationship. The mechanism of both quenching and enhancement is discussed and the options for further development of this novel metal sensing technique are presented.

Electroless Ni-Co-Cu-P Alloy Deposition in Alkaline Hypophosphite Based Bath

The use of electroless deposition method to deposit nickel alloy attracts attention due to its uniformity, corrosion resistance in neutral media and low friction. Quaternary nickel alloy deposit can be achieved by adding metal ion additive into the plating bath. Furthermore, the use of alkaline bath can accelerate the deposition rate, and provide sufficient thickness for corrosion protection. In this study, an electroless quaternary nickel alloy is deposited on iron coupons by adding cobalt and copper ions in hypophosphite based Ni-P alkaline bath. The nickel alloy deposit surface morphology is studied using scanning electron microscope (SEM) and x-ray fluorescence (XRF). Corrosion behavior of the nickel alloy is investigated using polarization curve measurement in 3.5wt% NaCl aqueous solution. From the results, the elecroless Ni-Co-Cu-P alloy coating produced at higher plating bah pH is harder than the lower bath pH. Higher Co, Cu and P content in the Ni alloy exhibit broader passive area in the polarization curve measurement results.

Optimisasi produksi biogas dari limbah lateks cair pekat dengan penambahan logam Optimization of biogas production from concentrated-latex effluent with addition of metals

Summary The treatment of concentrated-latex effluent process applied in the field presently, has not obtain optimum additional benefits. Besides that, the technology using ponding system needs wide area and causes air pollution that such a way caused conflicts with society. The application concept of clean industry: reuse, reduction, recovery and recycling, makes the possibilities to convert the effluent to be usefull products. One of the alternative effluent process is by utilizing it as the source of renewable energy, that is in the form of biogas as an alternative energy. The preliminary research showed that the use of spontaneous latex skim coagulation, the addition of 1% manure as source of seed, and leaf biomass as the source of carbon could increase the biogas production. This research was carried out to optimize biogas production by adding metal ion and to observe the parameters which influenced every stage of biogas production. At the beginning of the process, pH showed increasing due to the hydrolysis process that generally occured in acid condition, but it remained stable (6.6-7.7) in the next steps, whereas, the VFA value as well as BOD value tended to increase. COD value had fluctuative inclination caused by the conversion of organic compounds to produce biogas and the hydrolysis process of leaf biomass to organic compounds that decom-posed to further biogas. The best result of biogas production was showed by addition of Fe3+ with optimum concentration 0.50 mg/L effluent.

Optimisasi produksi biogas dari limbah lateks cair pekat dengan penambahan logam Optimization of biogas production from concentrated-latex effluent with addition of metals

Summary The treatment of concentrated-latex effluent process applied in the field presently, has not obtain optimum additional benefits. Besides that, the technology using ponding system needs wide area and causes air pollution that such a way caused conflicts with society. The application concept of clean industry: reuse, reduction, recovery and recycling, makes the possibilities to convert the effluent to be usefull products. One of the alternative effluent process is by utilizing it as the source of renewable energy, that is in the form of biogas as an alternative energy. The preliminary research showed that the use of spontaneous latex skim coagulation, the addition of 1% manure as source of seed, and leaf biomass as the source of carbon could increase the biogas production. This research was carried out to optimize biogas production by adding metal ion and to observe the parameters which influenced every stage of biogas production. At the beginning of the process, pH showed increasing due to the hydrolysis process that generally occured in acid condition, but it remained stable (6.6-7.7) in the next steps, whereas, the VFA value as well as BOD value tended to increase. COD value had fluctuative inclination caused by the conversion of organic compounds to produce biogas and the hydrolysis process of leaf biomass to organic compounds that decom-posed to further biogas. The best result of biogas production was showed by addition of Fe3+ with optimum concentration 0.50 mg/L effluent.

Size-controllable synthesis of carbon spheres with assistance of metal ions

This is great interest in tuning diameter of carbonaceous materials for applications in energy storage, templates and separation etc. In this study, different texture and size distribution of carbon spheres were obtained in only one step by hydrothermal carbonization of glucose using metal chlorides, such as NaCl, MgCl2, CaCl2 and FeCl3. Then, structure and chemical composition of the products were characterized by means of SEM, TEM, FTIR and Zetasizer. The combination of these results had allowed us to infer that adding metal ions was more efficient than prolonging hydrothermal treatment in promoting the formation of carbon microspheres. In addition, metal ions strength is proportional to the size of the particles. At last, through investigating the morphology transformation process of the products, a possible growth mechanism was proposed.

Using strain Rhodotorula mucilaginosa to produce carotenoids using food wastes

Carotenoids are important natural pigments with antioxidant properties, used extensively as a coloring agent in food, cosmetic additives and health foods. Owing to health concerns, the demand for natural carotenoids has increased significantly in recent years. In this research yeast strain Rhodotorula mucilaginosa F-1 was isolated from a biodiesel plant activated sludge tank for carotenoids biosynthesis. The results revealed the optimum pH and temperature for carotenoids synthesis were 5 and 25 °C, respectively. The percentages of β-carotene, torulene and torularhodin were 28.8%, 48.0% and 23.2%, respectively, under the optimum growth condition (pH5 and 25 °C). After adding metal ions, the total amount of carotenoids and biomass growth were improved. The cell growth and carotenoids synthesis using molasses waste were both better than those using YM medium (control). The carotenoids composition was 23.8% β-carotene, 67.5% torulene and 8.7% torularhodin. Molasses might have potential as acceptable waste due to its low cost and natural carotenoids production ability.

Photocatalytic property of metal ion added SrTiO3 to Overall H2O splitting

The effects of the metal ion addition to SrTiO3 to the overall H2O splitting were investigated to improve the photocatalytic activity. The addition of metal ions was carried out by impregnation method. The preparation condition of metal ion added SrTiO3 was examined with applying Na+ ion as additive and SrTiO3 prepared by polymerizable complex method. The photocatalytic activity was markedly improved by the addition of Na+ ion and calcined above 1173K. The preferable state of the photocatalyst was Na ion (2atm%) added SrTiO3 obtained by calcination at 1273K and the photocatalytic activity with a Rh0.3Cr1.7O3 (Rh:0.3wt%) co-catalyst was 16mmol/h for H2 and 8mmol/h for O2 production. The apparent quantum yield (AQY) was 16% under the irradiation of 360nm. The photocatalytic performance of Na+ ion added various SrTiO3 and the effects of various metal ion addition to SrTiO3 to the photocatalytic activity of the overall H2O splitting were investigated to discuss the influence of the added metal ions to the photocatalytic activity.

Model Studies on the Antioxidative Effect of Polyphenols in Thermally Treated D-Glucose/L-Alanine Solutions with Added Metal Ions.

The influence of different polyphenolic compounds (PPs) on the Maillard reaction in a d-glucose/l-alanine model system with or without metal ions was studied under various reaction conditions. At temperatures up to 100 °C the PPs showed pro-oxidative effects due to their reducing effects on metal ions. This can be explained by a combined redox cycling mechanism of metals and PPs that promotes oxidation in the Maillard reaction. The antioxidative capacities of the PPs were measured with three different assays and correlated directly with their pro-oxidative effects on d-glucosone formation. The degree of the pro-oxidative effect depended not only on the PPs' reducing potential and their antioxidative ability but also on their concentration, the temperature, and the pH value of the model system. At low pH values and temperatures, the PPs were more stable and therefore showed an increased pro-oxidative tendency. In contrast, some of the used PPs were almost completely degraded at temperatures of 130 °C, and the formed polymers were able to complex metal ions. In the absence of these catalyzing ions, the oxidation ratio of d-glucose to d-glucosone was decreased.

Effects of Al3 +, W6 +, Nb5 + and Pb2 + on the structure and properties of borotellurite glasses

The effects of addition of Al3+, W6+, Nb5+ and Pb2+ on the density, thermal, optical properties of borotellurite glasses and on the B–O, Te–O and Al–O speciation are studied. Density maximizes in glasses containing Pb2+ and minimizes in glasses with Al3+. The optical absorption cut-off wavelength increases with the addition of heavy metal ions while Al3+ shifts it to lower wavelengths. W6+, Nb5+ and Al3+ strengthen the borotellurite network and enhance the glass transition temperatures, however Pb2+ decreases it. The glass transition temperature is a linear function of the average single bond energy of the glass network. 11B Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared studies found that the BO4 structural units are unstable in the presence of Al3+, W6+ and Nb5+, however Pb2+ has an opposite effect and promotes the formation of BO4. 27Al MAS NMR showed that alumino-borotellurite glasses contain AlO6, AlO5 and AlO4 structural units whose relative concentrations depend on alumina mol%. Raman spectroscopy was used to determine Te–O coordination in glasses, the later decreased on adding metal ions and Al3+ produced a maximum suppression of TeO4 units.

Effects of flavonoids on physical and oxidative stability of soybean oil O/W emulsions

Flavonoids have attracted attention due to pharmacological and antioxidative activities. The effects of flavonoids on the physical and oxidative stabilities of lecithin emulsified soybean oil-in-water (O/W) emulsions were investigated at 25°C during 29 days of storage. Addition of 100 ppm hesperidin, hesperitin, rutin, or quercetin improved the physical stability of O/W emulsions but did not change particle size values, compared to a control with no flavonoids during storage. Quercetin showed the highest antioxidant activity for inhibition of lipid oxidation based on lowered lipid hydroperoxide formation and 2-thiobarbituric acid reactive substances values in emulsions, followed by rutin, hesperitin, and hesperidin. Hesperidin and hesperitin did not affect antioxidative activities in O/W emulsions under metal ion-catalyzed conditions. Addition of hesperidin, hesperitin, rutin, and quercetin to soybean oil O/W emulsions improved the physical and oxidative stability of emulsions lacking added metal ions.