STUDY ON DEGRADATION OF POLYETHYLENE FILMS CONTAINING ADDITIVES WITH FERROUS ION AT COMPOSTING TEMPERATURES

Polyethylene (PE) films with additives consisting mainly of oleic acid and ferrous ions were subjected to accelerated degradation at simulated composting temperatures.Based on Fourier transform infrared spectroscopy and measurements of mechanical properties and viscosity average molecular weight,the degradation of the films was characterized and the degradation mechanism was discussed.The films containing additives with ferrous ions represent considerable decreases in molecular weight,and the carbonyl groups and hydroperoxides in the aging films show different trends of increase with the aging time.These results indicate that the ferrous ion plays an important role in the degradation of PE films and accelerates the degradation of PE.

Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

In the interest of accelerating aniline degradation, Fe2+ and chelated Fe2+ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate(EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn't follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+ results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

Structure regulation for ultra-high luminescence quantum yield lanthanide complex and simultaneous detection of cancer marker and ferrous ion

The exploitation of a highly selective and sensitive probe to detect both cancer marker and metal ion is of great importance.In this work,the "one stone two bird" agent of 1,10-phenanthroline(phen) is designed to disrupt the polymeric lanthanide MOFs(LnMOFs,[Ln(CHO_(2))_(3)]n,Ln=Tb,la;Eu,1 b,CHO_(2)=formic acid) {[Ln(CHO_(2))_(4)·(C_(2) H_(8) N)]n,Ln=Y,2 a;Gd,2 b;Dy,2 c,C_(2)H_(8) N=dimethylamine}) into a soluble mononuclear species [Ln(phen)_(2)(NO_(3))_(3),Ln=Tb,3 a;Eu,3 b] as well as to provide an antenna for efficient photons absorption,resulting in an ultra-high luminescence quantum yield(QY,90%) europium complex.The luminescence QY is among the highest record of monomeric(zero-dimensional) lanthanide complexes.Furthermore,mononuclear Tb3+complex(3 a) functions as a multiplex sensor towards both Fe^(2+)and cancer marker of 5-hydroxyindole-3-acetic acid(5-HIAA).Importantly,the limit of detection(LOD)for sensing 5-HIAA is an ultra-sensitive value of 1 × 10 s mol/L,which is even lower than that necessary for the early diagnosis of carcinoid tumors.More interestingly,sensing results in simulated urine reveals that 3 a has potential application for early diagnosis in the clinic.

A High Selective Chemiluminescent Probe Derived from Iso-luminol Enabling High Sensitive Determination of Ferrous Ions in the Environmental Waters

A new chemiluminescence(CL)reagent named 4-amino-5-thiocyanato-phthalyl-hydrazine(iso-luminol-SCN)is synthesized by the bromide-mediated substitution reaction of iso-luminol with sodium thiocyanate in dimethyl formamide(DMF)at room temperature.Strong CL is observed for iso-luminol-SCN oxidized by hydrogen peroxide(H2O2)in the presence of Fe^(2+),with the CL intensity strongly depending on the concentration of Fe^(2+)and being hardly interferred by other common metal ions.Based on this fact,a flow injection CL method is established for the high sensitive and selective determination of Fe^(2+).The CL intensity was linearly correlated with the concentration of Fe^(2+)in the range of 1.0×10^(–8) mol·L^(-1) to 1.0×10^(–5) mol·L^(-1) following the equation CLnet=166.3c+57.7(c,×10^(–6) mol·L^(-1);n=7;R2=0.9988).The detection limit is calculated to be 3.2×10–9 mol·L^(-1) Fe^(2+)based on the 3S0/K principle.The relative standard deviation(RSD)was 3.7%for 1.0×10^(–6) mol·L^(-1) Fe^(2+)(n=11),a support for the precision of Fe^(2+)measurement.The recoveries of Fe^(2+)were obtained in the range of 98.8%—101.6%in three real water samples,showing the applicability and reliability by the proposed method.The possible CL mechanism is proposed based on the kinetic characteristic of the CL reaction and the CL spectrum.

A Novel Enhancer for Fe^(2+)-Catalyzed Light Emission Reaction of Luminol and Dissolved Oxygen

EDTA was used as an enhancer for Fe 2+ catalyzed light emission from luminol oxidation by dissolved oxygen. As a result, the limit of detection for ferrous ion with flow injection analysis was improved by a factor of 160 by addition of EDTA to the luminol solution. Fe 2+ and Fe 3+ were determined simultaneously with a novel copper-coated zinc reductor minicolumn installed in one of the shunt after sample splitting in the manifold. The reductor minicolumn can be used for 3000 determinations at least. The dynamic range of determination was 1×10 -9 ～1×10 -5 mol·L -1 , with the limit of detection of 2.7×10 10 and 3.5×10 10 mol·L 1 ,for Fe 2+ and Fe 3+ , respectively. The preci sion for determination of 2×10 7 mol·L 1 of Fe 2+ and Fe 3+ was 2.3% and 4.0% (n=8), respectively, at a sampling rate of 60 h -1 . Cr 3+ and Co 2+ interfere. Fe 2+ and Fe 3+ in mixture were determined with satisfactory results. Samples of Fe 2+ and Fe 3+ were determined simultaneously and the results in good agreement with the standard spectrophotometric method. Indications were shown that EDTA functions as an enhancer, Fe 2+ as a catalyst, and oxygen is the oxidant of the chemiluminescent reaction, and the mechanism of the reaction was discussed.

Degradation of aniline by Fe^(2+)-activated persulfate oxidation at ambient temperature

The aniline degradation by persulfate activated with ferrous ion (Fe2+ ) was investigated in batch reactor at ambient temperature. The experimental factors in aqueous solutions including persulfate concentration, Fe2+ concentration, pH and ionic strength level were discussed. It is demonstrated that, aniline degradation rate increases with increasing persulfate concentration, but much more ferrous ion inhibits the aniline degradation. When the aniline concentration is 0.10 mmol/L, the maximum aniline degradation occurs at the S2O82- to Fe2+ molar ratio of 250/5 at pH 7.0. In the pH range of 5.0-8.5, increasing pH causes higher aniline degradation. What's more, the increase of ionic strength in solution causes inhibiting in the reaction. Produced intermediates during the oxidation process were identified using gas chromatography-mass spectrometry (GC-MS) technology. And degradation pathways of aniline were also tentatively proposed.

Study on Catalytic Wet Oxidation of H_2S into Sulfur on Fe/Cu Catalyst

A wet catalytic oxidation at room temperature was investigated with solution containing ferric, ferrous and cupric ions for H2S removal. The experiments were carried out in a two step process, and the results obtained show that the removal efficiency of H2S can always reach 100% in a 300 mm scrubbing column with four sieve plates, and the regeneration of ferric ions in 200 mm bubble column can match the consumed ferric species in absorption. Removal of H2S, production of elemental sulfur and regeneration of ferric, cupric ions can all be accomplished at the same time. No raw material is consumed except O2 in flue gas or air, the process has no secondary pollution and no problem of catalyst degradation and congestion.

Effect of iron valence on hydrothermal preparation of pyrochlore-type tungsten oxide

Pyrochlore-type tungsten oxide (PTO), WO3·0.5H2O, is an emerging material with very wide potential applications. The influences of iron valences and the additive amount of ferrous ion on tungsten crystallization ratio and the acceleration mechanism of ferrous ion were investigated when PTO was hydrothermally prepared in aqueous ammonium tungstate solution containing ammonium carbonate. The results show that ferrous ion can remarkably accelerate tungsten crystallization while both elemental iron and ferric ion have little influence on the crystallization. Moreover, the tungsten crystallization ratio increases with increasing the amount of ferrous ions added and reaches the maximum of about 60% with ferrous ion concentration of 16 g/L. FTIR analysis of the spent solution after PTO crystallization shows that ferrous ion can accelerate the conversion of WO4 tetrahedral to WO6 octahedron. Combined with XPS and XRD analyses of the hydrothermal product, the acceleration effect of ferrous ion on tungsten crystallization could basically be attributed to the increase in the interplanar spacing of PTO lattice caused by the incorporation of ferrous ion into PTO crystal lattice. The results presented is conducive to the efficient preparation of PTO powder and cleaner tungsten metallurgy.

Effects of ferrous and manganese ions on anammox process in sequencing batch biofilm reactors

Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequencing batch biofilm reactors were used to investigate the effects of ferrous and manganese ions on nitrogen removal efficiency and the potential of metal ions serving as electron donor/acceptors in the anammox process. Fluorescence in situ hybridization analysis was applied to investigate the microbial growth. Results showed that the nitrogen removal increased at high concentrations of Fe2＋ and Mn2＋ and the maximum removal efficiency was nearly 95% at Fe2＋ 0.08 mmol/L and Mn2＋ 0.05 mmol/L, which is nearly 15% and 8% higher than at the lowest Fe2＋ and Mn2＋ concentrations （0.04 and 0.0125 mmol/L）. The stabilities of the anammox reactor and the anammox bacterial growth were also enhanced with the elevated Fe2＋ and Mn2＋ concentrations. The Fe2＋ and Mn2＋were consumed by anammox bacteria along with the removal of ammonia and nitrite. Stoichiometry analysis showed Fe2＋ could serve as an electron donor for NO3-N in the anammox process. Nitrate could be reduced with Fe2＋ serving as the electron donor in the anammox system, which causes the value of NO^-N/NH4-N to decrease with the increasing of N-removal efficiency.

Antioxidant Activity of Pomegranate Juice and Punicalagin

Plant polyphenols are reported to have bioactive properties, which may be used for protection against diseases. Therefore, the aim of this research was to investigate the antioxidant activities of a pomegranate tannin polyphenol compound, punicalagin and pomegranate juice. The presence of punicalagin in pomegranate husk (US) and pomegranate juice (US & UK) was compared with a punicalagin standard using high performance liquid chromatography (HPLC) and liquid chromatography-mass spectroscopy (LC-MS) which are highly sensitive and selective analytical methods for the separation and identification of phenolic compounds and anthocyanins. Antioxidant mechanisms involving DPPH radical scavenging activity, hydrogen peroxide scavenging, ferrous chelating and reducing ability were also studied on pomegranate juice and standard punicalagin. The present study shows a high degree of similarity of HPLC and LC-MS results between the punicalagin commercial standard (Sigma Aldrich) and US pomegranate husk extracted with methanol. In contrast, in the methanol juice extract obtained from US and UK, higher hydrogen peroxide scavenging activity was achieved by 0.1 mg/ml from both punicalagin and pomegranate juice when compared with butylated hydroxytoluene (BHT) or trolox (p ≤ 0.01). Punicalagin and pomegranate juice exhibited ferrous chelating ability significantly lower than Ethylenediaminetetraacetic acid. These findings confirmed that punicalagin was present in pomegranate husk compared to pomegranate juice, as measured using a punicalagin standard. The antioxidant mechanism experiments concluded that, the pomegranate juice has a significantly higher radical scavenging activity in comparison with punicalagin (p ≤ 0.01). However, punicalagin showed significant ferrous chelating activity and reducing power ability in a dose-dependent manner as compared with pomegranate juice.

Impacts of Fe2+on 5-aminolevulinic acid(ALA)biosynthesis of Rhodobacter sphaeroides in wastewater treatment by regulating nif gene expression

This study aimed to increase bacterial growth and 5-aminolevulinic acid（ALA） biosynthesis of Rhodobacter sphaeroides in wastewater treatment through adding ferrous ion（ Fe2＋ ）. Results demonstrated that Fe2＋ effectively enhanced the biomass production and ALA yield of R. sphaeroides. Moreover, the optimal Fe2＋ dosage was found to be 400 μmol/L, which was associated with the highest biomass of 4015.3 mg/L and maximum ALA yield of 15.9 mg/g-dry cell weight（mg/g-DCW）. Mechanism analysis revealed that Fe2＋ vastly improved Adenosine Triphosphate（ATP） production by up-regulating the nif gene expression, and increasing ATP enhanced the biomass and ALA yield by supplying energy for bacterial growth and ALA biosynthesis, respectively. Correlation analysis showed that the ALA and ATP yields had positive relation with nifA and nifU gene expression. In addition, the nifA and nifU gene expression displayed high consistency of co-transcription at the optimal Fe2＋ dosage.

Antioxidant and anti-diabetic activities in commercial and homemade pomegranate molasses in Lebanon

Pomegranate fruit and its derived products are rich sources of bioactive compounds.They have many biological activities.Pomegranate molasses(PM)is a thick,traditional Middle Eastern syrup used in many recipes for Lebanese and international cuisines.It is a highly nutritious product which makes it of great interest.The purpose of this study was to assess the phytochemical composition,antioxidant and anti-diabetic properties of homemade and commercial PM consumed in Lebanon using samples collected from households in rural areas(n=4)and the market(n=28).The objectives of this study were to determine their total phenolic content using the Follin-Ciocalteu method,their total flavonoid content using aluminum chloride method,their antioxidant activity using DPPH radical scavenging as well as ferrous ion chelating assays and their anti-diabetic activity usingα-amylase andα-glucosidase inhibitory activities with acarbose,a known anti-diabetic drug,used as the standard reference.Homemade PM samples exhibited a higher antioxidant activity than commercial samples,with the most active homemade PM sample having IC_(50)values of 0.09 mg/mL(DPPH radical scavenging assay)and 46.78%ferrous ion chelating assay).Homemade PM samples also showed higher anti-diabetic activity than commercial samples,with the most active homemade PM sample having an IC_(50)values of 0.63 mg/mL(α-amylase inhibitory activity)and of 0.41 mg/mL(α-glucosidase inhibitory activity)and being almost as active as acarbose with both enzymes(1.5 times).Significant inverse strong/moderate correlations were observed between total phenolic content/total flavonoid content and the IC_(50)value of DPPH radical scavenging assay,indicating positive associations between total phenolic and flavonoid contents and antioxidant activity.In addition,significant negative moderate correlations were observed between total phenolic/flavonoid contents andα-amylase inhibitory activity,indicating positive associations between total phenolic and flavonoid contents and anti-diabetic activity.