This study aimed to evaluate the quality of water from village boreholes by measuring physicochemical parameters such as nitrates, nitrites, and total organic carbon (TOC). Forty-five (45) village pumps from the South...This study aimed to evaluate the quality of water from village boreholes by measuring physicochemical parameters such as nitrates, nitrites, and total organic carbon (TOC). Forty-five (45) village pumps from the Southern (Basse Côte) and the Northern (Korhogo) region of Cte d’Ivoire (west Africa) were sampled. Physicochemical parameters such as temperature, pH, conductivity at 25˚C, and turbidity were determined in situ, while nitrite and nitrate were analyzed according to ISO 10304-1 (2007) standard and total organic carbon (TOC) by NF EN 1484 (1997) standard. The results showed that the borehole waters of the Basse Côte and Korhogo analyzed are acidic, with an average temperature of 27.51˚C ± 0.16˚C and 29.95˚C ± 0.51˚C respectively for the Basse Côte and Korhogo regions. The borehole waters of the Basse Côtedo not contain nitrites, while those of Korhogo have average nitrite contents of 0.32 mg/l. The average nitrate rate in the waters of the Basse Côte and Korhogo are 12.08 ± 2.11 mg/l and 11.03 ± 3.18 mg/l respectively. The average TOC concentration of the waters of the Basse Côte is 1.28 ± 0.32 mg/l and that of Korhogo is 0.56 ± 0.09 mg/L. The study showed that the borehole waters of the Basse Côte and Korhogo have average temperatures between 27.4˚C and 29.95˚C with a slightly acidic pH value and acceptable salinity. The TOC concentrations obtained at the different sampling points were all below the French standard (2 mg/L) except for certains pumps of the Basse Côte. The water samples from the Basse Côte were devoid of nitrite. On the other hand, those from Korhogo revealed the presence of nitrite. Also, the borehole waters of the regions of the Basse Côte and Korhogo contain relatively high nitrate contents, presumably due to anthropometric activity. Overall, our study on the quality of drinking water showed that the waters analyzed are in compliance with international standards and safe for consumption.展开更多
The nitrate reduction reaction(NtRR)has been demonstrated to be a promising way for obtaining ammonia(NH_(3))by converting NO3-to NH3.Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostruct...The nitrate reduction reaction(NtRR)has been demonstrated to be a promising way for obtaining ammonia(NH_(3))by converting NO3-to NH3.Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostructured nanowires(Co_(3)O_(4)/GDY NWs)by a simple two-step process including the synthesis of Co_(3)O_(4)NWs and the following growth of GDY using hex-aethynylbenzene as the precursor at 110°C for 10 h.Detailed scanning electron microscopy,high resolution transmission electron microscopy,X-ray photoelectron spectroscopy,and Raman characterization confirmed the synthesis of a Co_(3)O_(4)/GDY heterointerface with the formation of sp-C-Co bonds at the interface and incomplete charge transfer between GDY and Co,which provide a con-tinuous supply of electrons for the catalytic reaction and ensure a rapid NtRR.Because of these advantages,Co_(3)O_(4)/GDY NWs had an excellent NtRR performance with a high NH3 yield rate(YNH3)of 0.78 mmol h^(-1)cm^(-2)and a Faraday efficiency(FE)of 92.45%at-1.05 V(vs.RHE).This work provides a general approach for synthesizing heterostructures that can drive high-performance ammo-nia production from wastewater under ambient conditions.展开更多
The electrocatalytic nitrate reduction reaction (NO_(3)RR) powered by renewable energy offers a promising approach for simultaneously reutilization of nitrate and synthesizing high-value products.Nevertheless,theoreti...The electrocatalytic nitrate reduction reaction (NO_(3)RR) powered by renewable energy offers a promising approach for simultaneously reutilization of nitrate and synthesizing high-value products.Nevertheless,theoretical understanding of reaction mechanism was relative illusive,which is indispensable to rationally design of efficient catalysts.Besides,tuning the reaction microenvironment along with the scale-up device development is essential to promote the industrial deployment of electrocatalytic nitrate conversion,while relative research was overlooked.In this regard,recent advances in ammonia synthesis are firstly summarized,including the identification of active sites,exploration of the underlying reaction mechanisms,electrolyzer design and technical-economic analysis.Furthermore,electrocatalytic C–N coupling based on NO_(3)RR to produce higher-value products such as urea and amino acids are also reviewed,to extend the application potential and economic feasibility.Finally,we highlight the existing challenges and the demand of future research for NO_(3)RR.This review anticipates to provide insights into synthesis of high-value products via NO_(3)RR,bridging the gap from laboratory research to industrial fabrication.展开更多
Lithium metal batteries(LMBs)have received increasing attention due to the high energy density.However,the practical application of LMBs is limited due to the incompatibility of ester electrolytes.Transition metal(TM)...Lithium metal batteries(LMBs)have received increasing attention due to the high energy density.However,the practical application of LMBs is limited due to the incompatibility of ester electrolytes.Transition metal(TM)nitrates have been reported as effective additives in ester electrolyte to improve the stability of lithium anode.Unfortunately,the nitrates are restricted to use due to their poor solubility.We find that the nitrates containing crystal water have high solubility in ester electrolytes.Considering that most TM nitrates contain crystal water and the crystal water can be used as a perfect solubilizer of nitrates,thus,the method is of universality and facile without introducing any solubilizing agent.Herein,In(NO_(3))_(3.6)H_(2)O is chosen as one typical case with increased solubility up to 0.2 M compared with In(NO_(3))_(3)which hardly dissolves in ester electrolyte.The additive promotes the rapid and stable formation of the solid electrolyte interface(SEI),which effectively inhibits the lithium dendrites formation.Moreover,the induced cathode electrolyte interface(CEI)maintains the structural stability of Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811).As a result,the electrochemical performance of Li|NCM811 cell is obviously improved.Our study provides a new idea for dissolving nitrates in ester electrolytes and discloses the synergistic function of TM-ions.展开更多
A tripodal ligand, tris{2 [N (pyridine methanoyl)amino]ethyl}amine(L), and its complexes with rare earth nitrates were synthesized. These new complexes with the general formula of Ln(NO 3) 3·L·6H 2O(w...A tripodal ligand, tris{2 [N (pyridine methanoyl)amino]ethyl}amine(L), and its complexes with rare earth nitrates were synthesized. These new complexes with the general formula of Ln(NO 3) 3·L·6H 2O(where Ln=La, Nd, Eu, Tb, Y) were characterized by elemental analysis, IR spectra, thermal analysis, 1 H NMR spectra, molar conductivity and luminescent spectra. All the complexes are stable in air and their conductances in acetonitrile solution lie in the range of 142～150 S·cm 2·mol -1 , indicating 1∶1 type electrolytes. The IR and 1H NMR spectra of the ligand and its complexes show that all the C=O groups take part in coordination to the metal ions. The thermal behaviour of Eu complex shows that the weight losses at 75～120 ℃ and 120～210 ℃ correspond to the loss of four lattice water molecules and that of two coordinated water molecules, respectively. The luminescent spectra of the complexes of Eu(Ⅲ) and Tb(Ⅲ) were investigated in methanol.展开更多
Eight new complexes with the general formula of RE(Gly)(NO_3)_3(phen)_2·3H_2O (RE=La, Ce, Pr, Nd, Gd, Sm, Er, Y) were synthesized and characterized by elemental analysis, molar conductivity, IR spectra, UV spectr...Eight new complexes with the general formula of RE(Gly)(NO_3)_3(phen)_2·3H_2O (RE=La, Ce, Pr, Nd, Gd, Sm, Er, Y) were synthesized and characterized by elemental analysis, molar conductivity, IR spectra, UV spectra and thermal analysis. All the complexes are stable in air and their conductance values in acetonitrile lie in the range of 204.1～239.4 S·cm2·mol -1, indicating 1∶2 type electrolytes. The IR shows that all the COO of glycine and oxygen atom of NO_3- take part in the coordination to the RE ions. The thermal behavior of La complex shows that the weight losses at 75～120 ℃ and 145～170 ℃ correspond to the loss of two lattice water molecules and one coordinated water molecules, respectively.展开更多
Nine new solid complexes of Mn(Ⅱ),Co(Ⅱ),Cu(Ⅱ),Zn(Ⅱ.),Ag(Ⅰ) nitrates with 4',5'-dibromobenzo-15—crown—5(L_A),Ag(Ⅰ),Cd(Ⅱ)nitrates with tetrabromodibenzo—18—crown—6(L_B)and Cu(Ⅱ), Ag(Ⅰ) nitrates wit...Nine new solid complexes of Mn(Ⅱ),Co(Ⅱ),Cu(Ⅱ),Zn(Ⅱ.),Ag(Ⅰ) nitrates with 4',5'-dibromobenzo-15—crown—5(L_A),Ag(Ⅰ),Cd(Ⅱ)nitrates with tetrabromodibenzo—18—crown—6(L_B)and Cu(Ⅱ), Ag(Ⅰ) nitrates with 4'—bromo—5'—nitrobenzo—15—crown-5(L_c),having the compositions of M(NO_2)_2·L·nH_2O(M=Mn,Co, Zn,L=L_A,n=2;M=Cu,L=L_A,n=1.5; M=Cd, L=L_B,n=0; M=Cu,L=Lc,n=2) and AgNO_·L·nCH_3CN(L=LA,n=0; L=L_B,n=1; L=Lc,n=1/2) have been synthesized in nonaqueous solvent. All the isolated complexes have been characterized by elementary analysis, IR and UV spectra, differential thermal and thermogravimetric analysis, X—ray powder diffraction analysis, molar conductance and measuremends of solubility in some general solvents.展开更多
The emissions of NO_(2)and HONO from the KNO_(3)photolysis in the presence of TiO_(2)were measured using a round-shape reactor coupled to a NO_(x)analyzer.TiO_(2)played important roles in the emission flux density of ...The emissions of NO_(2)and HONO from the KNO_(3)photolysis in the presence of TiO_(2)were measured using a round-shape reactor coupled to a NO_(x)analyzer.TiO_(2)played important roles in the emission flux density of NO_(2)(R_(NO_(2)))and HONO(R HONO),depending on crystal structures and mass ratios of TiO_(2).R NO_(2)and R HONO significantly decreased with increasing the rutile and anatase mass ratios from 0 to 8 and 0.5 wt.%,respectively.Nevertheless,with further increasing the anatase mass ratio to 8 wt.%,there was an increase in R_(NO_(2))and R HONO.R NO_(2)on KNO_(3)/TiO_(2)/SiO_(2)had positive correlation with the KNO_(3)mass(1–20 wt.%),irradiation intensity(80–400 W/m^(2))and temperature(278–308 K),while it had the maximum value at the relative humidity(RH)of 55%.R HONO on KNO_(3)/TiO_(2)/SiO_(2)slightly varied with the KNO_(3)mass and temperature,whereas it increased with the irradiation intensity and RH.In addition,the mechanism for NO_(2)and HONO emissions from the nitrates photolysis and atmospheric implications were discussed.展开更多
Mixed rare earth nitrates （REi（NO3）3） in the aqueous solution was mixed with tri-n-butyl phosphate （TBP, （n-C4H9O）3PO） dissolved in kerosene for the formation of their corresponding complexes （REi（NO3）3...Mixed rare earth nitrates （REi（NO3）3） in the aqueous solution was mixed with tri-n-butyl phosphate （TBP, （n-C4H9O）3PO） dissolved in kerosene for the formation of their corresponding complexes （REi（NO3）3·ni（n-C4H9O）3PO） at 303 K. The effects of initial concentrations of both TBP and mixed rare earth nitrates on the equilibrium constants of their complex formations were investigated. The complexes were formed almost immediately after mixing. The simultaneous formations reached their chemical equilibria within a few minutes by shaking the mixture at 200 r/min. The chemical equilibrium constants of the complex formations were independent of the initial TBP concentrations. However, they were decreased by reducing the concentration of REi（NO3）3. All equilibrium constants of the simultaneous complex formations were less than 0.7, while the average molar ratio of TBP to REi（NO3）3 of the complexes varied between 1.0 and 1.6. The chemical equilibrium constant for the formation of La（NO3）3·（n-C4H9O）3PO was 0.09, while that of Dy（NO3）3·（n-C4H9O）3PO was 0.68. The ascending sequence of chemical equilibrium constants for the simultaneous formations was La, Ce, Pr, Nd, Eu, Y, Sm, Gd, and Dy.展开更多
Three new solid complexes of macrocyclic polyether ligand 2, 2'-dinitro-4, 5, 4', 5'bis-(15- crown-5)-dihenzo disulfide(L) with trivalent rare earth nitrates having composition of RE(NO_3)_3·L ·6...Three new solid complexes of macrocyclic polyether ligand 2, 2'-dinitro-4, 5, 4', 5'bis-(15- crown-5)-dihenzo disulfide(L) with trivalent rare earth nitrates having composition of RE(NO_3)_3·L ·6H_2O(RE=Ce, Pr, Nd) have been synthesized in acetonitrile. All the isolated complexes have been characterized by elementary analysis, IR and UV spectra, differential thermal and thermogravimetric analysis, X-ray powder diffraction analysis, molar conductance and measurements of solubility in some general solvents.展开更多
Within the framework of the contract of Sourou River, a survey of the groundwater quality was performed through 7 campaigns of water sampling and analysis from 2006 till 2012. The water samples resulted from 23 drilli...Within the framework of the contract of Sourou River, a survey of the groundwater quality was performed through 7 campaigns of water sampling and analysis from 2006 till 2012. The water samples resulted from 23 drillings and 9 wells located in the Sourou Valley. Among the analyzed physico-chemical parameters, the nitrates concentrations observed were worrisome. Out of 32 water sources, 14 (44%) supplied a nitrates content superior to the WHO threshold value for drinking water (50 mg NO3/L). Very high concentrations, superior to 500 mg NO3/L with a peak in 860 mg/L, were observed. Given the important variations observed from a sampling point to another, a generalized contamination of the total aquifer was not possible. An individual diagnosis allowed to identify the possible causes of this degradation. Several sources of contamination, in connection with the anthropological activities, were observed near the water facilities (drillings/wells): animal and human wild defecation, presence of nontight latrines, solid waste, wastewater discharges. It is also advisable to wonder about the impact of the dynamite use for digging wells, this one being able to leave nitrates in the water. With regard to the intensive use of water from the strongly contaminated wells and drillings by the rural populations of Sourou, implementing protection areas within which would be eliminated the sources of contamination in addition to health education among populations could improve the situation. Care should also be taken in the use of nitrates explosives for digging new wells or drillings.展开更多
Six new solid complexes of macrocyclic polyether ligand 4′-bromo-5′-nitrobenzo-15-crown-5(L)with Uivalent rare earth nitrates having composition of RE(NO_3)_3·L·mCH_3CN·nH_2O(RE=L_a--Nd,m=n=0, RE=Sm,B...Six new solid complexes of macrocyclic polyether ligand 4′-bromo-5′-nitrobenzo-15-crown-5(L)with Uivalent rare earth nitrates having composition of RE(NO_3)_3·L·mCH_3CN·nH_2O(RE=L_a--Nd,m=n=0, RE=Sm,Bu,m=0.1,n=1,4)have been synthesized in acetonitrile or acetone.All the isolated complexes have been char- acterized by elementary analysis,IR and UV spectra,differential thermal and thermogravimetric analysis,X-ray powder diffraction analysis,molar conductance and measurementa of solubility in some general solventa.It shows that coordination number of the rare earth cation in the complexes of La,Ce,Pr and Nd nitrate is eleven.展开更多
N-containing Ce_(2)Si_(2.5)Al_(0.5)O_(3.5)N_(3.5)(CeSiAlON) melilite was synthesized at 1550 and 1600℃ for 5 h from CeO_(2),Si,Al,and Al_(2)O_(3) in nitrogen by using Y_(2)O_(3) and transition-metal nitrates(Co(NO_(3...N-containing Ce_(2)Si_(2.5)Al_(0.5)O_(3.5)N_(3.5)(CeSiAlON) melilite was synthesized at 1550 and 1600℃ for 5 h from CeO_(2),Si,Al,and Al_(2)O_(3) in nitrogen by using Y_(2)O_(3) and transition-metal nitrates(Co(NO_(3))_(2)·6 H_(2) O and Ni(NO_(3))_(2)·6 H_(2)O) as additives.The effects of Y_(2)O_(3) and transition-metal nitrates on the phase,microstructures and photoluminescence properties of CeSiAlON melilite were studied.The incorporation of Y_(2)O_(3) can promote the reaction of raw materials to a low degree,and results in a unit cell shrinkage of CeSiAlON due to the smaller radius of Y atom than that of Ce atom.The transition-metal nitrates can accelerate the reaction clearly and facilitate the formation of CeSiAlON fibers.The photoluminescence(PL) properties of CeSiAlON melilite presents a board violet emission band because of the 5 d-4 f transitions of Ce^(3+),and the additives can enhance the PL emission intensities of specimen significantly.展开更多
The interactions of 2,2'-bipyridyl with the lanthanide nitrates were studied and complexes of the formula Ln(NO_8)_8(bipy)_8 were isolated from water -ethanol mixed solvent.The complexes were characterized by elem...The interactions of 2,2'-bipyridyl with the lanthanide nitrates were studied and complexes of the formula Ln(NO_8)_8(bipy)_8 were isolated from water -ethanol mixed solvent.The complexes were characterized by elemental analysis, conductivity measurments,IR spectra and DAT-TG analysis.展开更多
This paper presents results of nitrites and nitrates determination in two types of baby foods： commercial products in jars and their homemade conventional counterparts. Nitrites levels in all analyzed samples were be...This paper presents results of nitrites and nitrates determination in two types of baby foods： commercial products in jars and their homemade conventional counterparts. Nitrites levels in all analyzed samples were below of the detection limit （〈 0.9 mg/kg） of applied spectrophotometric method with Griess reagent. Nitrates contents in commercial products ranged： 9.1-38.1 mg/kg while in homemade baby foods levels between 26.6 mg/kg and 118.8 mg/kg were obtained. All the contents of nitrates were lower than the EU legislation maximum limit （200 mg/kg）. Comparison of each type of commercial product with its homemade counterpart baby food evidenced significant differences （p 〈 0.05） in average nitrates levels in favor of the first type. Apart from determining and comparing the levels of nitrates in the baby food samples also risk assessment for an average 6-months old infant to nitrates exposure was conducted. The estimated nitrates intake with a typical portion of 200g of baby food ranged between 6% and 25.7% of acceptable daily intake for commercial and from 18.0% to 80.3% for homemade ones.展开更多
Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free co...Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.展开更多
Objective: To investigate the protective effect of nitrates postconditioning on myocardial ischemia-reperfusion injury and whether it plays a regulatory role in TNF-α in patients with STEMI during PCI. Methods: Patie...Objective: To investigate the protective effect of nitrates postconditioning on myocardial ischemia-reperfusion injury and whether it plays a regulatory role in TNF-α in patients with STEMI during PCI. Methods: Patients with STEMI who underwent PCI were selected, except for obvious anemia, head trauma, cerebral hemorrhage, hypotension (systolic blood pressure less than 90 mmHg), and patients with autoimmune diseases, all kinds of acute and chronic infections and malignant tumors. They were randomly divided into PCI standardized treatment group and isosorbide dinitrate postconditioning during PCI group. The concentrations of cTnI and TNF-α in serum were detected by ELISA method in each group before PCI and after 2 hours, 1 day, 4 days and 7 days of PCI. Results: 1) There were no statistically significant differences in sex, age, smoking history, diabetes, hypertension and blood lipid abnormality in two groups. 2) Before operation, the concentration of cTnI in two groups was not statistically significant. The concentration of cTnI in the experimental group was lower than that of the control group after 4 days and 7 days of PCI, and P α in two groups before operation. The concentration of TNF-α in the experimental group was lower than that in the control group after 1 day, 4 days and 7 days of PCI, and P α in two groups was both in 1 day after operation, and the peak level of the experimental group and the level of each time after the operation were lower than that of the control group. Conclusion: Nitrates postconditioning during PCI in patients with STEMI has a protective effect on myocardial ischemia-reperfusion injury. Nitrates postconditioning has an effect to reduce the level of TNF-α of patients with STEMI after PCI treatment, and may have the mechanism of alleviating the inflammatory response after myocardial ischemia and reperfusion.展开更多
The effects of different chemical fertilizer combinations (N, P and K) oncrop yield, N uptake and nitrate distribution and accumulation to a depth of 100 cm were studied ina cinnamon fluvo-aquic soil profile (Beijing)...The effects of different chemical fertilizer combinations (N, P and K) oncrop yield, N uptake and nitrate distribution and accumulation to a depth of 100 cm were studied ina cinnamon fluvo-aquic soil profile (Beijing) with a continuous winter wheat-summer maize croppingsystem for nine years. The experiment consisted of 7 treatments: no fertilizer control (CK); Nalone, N in combination with K (NK), P (NP), and P and K (NPK and N1PK); and P and K in combinationwithout N (PK). The rate of N was 150 kg ha^(-1) for the N treatments except Treatment N1PK withhigher N rate (195 kg ha^(-1)), and the rates of P (P_2O_5) and K (K2O) were 75 and 37.5 kg ha^(-1),respectively. The applications of N combined with P and K (NK, NP and NPK) resulted in higher cropyields than a single application of N. The yields followed the order: NPK > NP > N1PK > PK > NK > N> CK for winter wheat, and NPK > N1PK > NP > NK > N > PK > CK for summer maize. Supplement of N withP or K, or both P and K resulted in a higher average N uptake of the two crops, which was in adecreasing order NPK > NP > N1PK > NK > N > PK > CK. The combinations also increased apparent Nrecovery more than N alone and CK. The nitrate content in the profile was thus reduced more in thecombination treatments. The nitrate accumulation in the soil profiles followed the order: N > NK >N1PK > NPK > NP > CK > PK. Higher N uptake by the adequately fertilized crops (Treatment NPK)reduced nitrate accumulation in the profile and thus reduced nitrate leaching. The optimum N:P:Kratio was thus of paramount importance in increasing yields and N uptake of crops and reducingnitrate leaching losses.展开更多
For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality...For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality in Beijing. To investigate the effects of SO2 and NOx reductions on the particulate sulfate and nitrate concentrations as well as their size distributions, size-segregated aerosol samples were collected using micro-orifice uniform deposit impactors （MOUDIs） at urban and downwind rural sites in Beijing before and after full-scale controls. During the sampling period, the mass concentrations of fine particles （PMI.s） at the urban and rural sites were 94.0 and 85.9 p.g m-3, respectively. More than 90% of the sulfates and 60% of nitrates formed as fine particles. Benefiting from the advantageous meteorological conditions and the source controls, sulfates were observed in rather low concentrations and primarily in condensation mode during the Olympics. The effects of the control measures were separately analyzed for the northerly and the southerly air-mass-dominated days to account for any bias. After the control measures were implemented, PM, sulfates, and nitrates were significantly reduced when the northerly air masses prevailed, with a higher percentage of reduction in larger particles. The droplet mode particles, which dominated the sulfates and nitrates before the controls were implemented, were remarkably reduced in mass concentration after the control measures were implemented. Nevertheless, when the polluted southerly air masses prevailed, the local source control measures in Beijing did not effectively reduce the ambient sulfate concentration due to the enormous regional contribution from the North China Plain.展开更多
In the present study, we investigated the performance of clay mineral originated from a dam situated in Morocco (Agadir city), as natural, low-cost, alternative and eco-friendly adsorbent for removal of nitrates ions ...In the present study, we investigated the performance of clay mineral originated from a dam situated in Morocco (Agadir city), as natural, low-cost, alternative and eco-friendly adsorbent for removal of nitrates ions from aqueous solution within a batch process. The clay was characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Dispersive Energy of Spectroscopy (EDS), Fourier Transform Infrared (FTIR) and surface area analysis (BET). The effects of various experimental parameters are examined such as contact time, initial concentration of pollutant, adsorbent mass and solution pH. The removal of nitrate was 71.89% at natural pH (pH = 5.1) using 1 g/l of adsorbent in 500 ml of nitrate solution having initial concentration of 300 mg/l (effect of contact time). Adsorption kinetic study revealed that the adsorption process followed first order kinetic. Theoretical correlation of the experimental equilibrium adsorption data for the Nitrate-New Clay system was properly explained by the Langmuir isotherm model. The maximum adsorption capacity was Qm, exp = 244.06 mg/g at 20℃ and at natural pH (with Qm, cal = 250 mg/g). An increase in adsorbent dosage increased the percent removal of nitrate, R = 1 g/l was considered as optimum dose and was used for further study. The pH heavily affected the adsorption capacity, and the percentage removal was found to decrease with increase in pH. The obtained results indicated that this New Clay (NC) was very good adsorbent for NO3-, interesting alternative material with respect to more costly adsorbent used, and could be used as a highly efficient adsorbent for the separation of nitrate from drinking or waste water.展开更多
文摘This study aimed to evaluate the quality of water from village boreholes by measuring physicochemical parameters such as nitrates, nitrites, and total organic carbon (TOC). Forty-five (45) village pumps from the Southern (Basse Côte) and the Northern (Korhogo) region of Cte d’Ivoire (west Africa) were sampled. Physicochemical parameters such as temperature, pH, conductivity at 25˚C, and turbidity were determined in situ, while nitrite and nitrate were analyzed according to ISO 10304-1 (2007) standard and total organic carbon (TOC) by NF EN 1484 (1997) standard. The results showed that the borehole waters of the Basse Côte and Korhogo analyzed are acidic, with an average temperature of 27.51˚C ± 0.16˚C and 29.95˚C ± 0.51˚C respectively for the Basse Côte and Korhogo regions. The borehole waters of the Basse Côtedo not contain nitrites, while those of Korhogo have average nitrite contents of 0.32 mg/l. The average nitrate rate in the waters of the Basse Côte and Korhogo are 12.08 ± 2.11 mg/l and 11.03 ± 3.18 mg/l respectively. The average TOC concentration of the waters of the Basse Côte is 1.28 ± 0.32 mg/l and that of Korhogo is 0.56 ± 0.09 mg/L. The study showed that the borehole waters of the Basse Côte and Korhogo have average temperatures between 27.4˚C and 29.95˚C with a slightly acidic pH value and acceptable salinity. The TOC concentrations obtained at the different sampling points were all below the French standard (2 mg/L) except for certains pumps of the Basse Côte. The water samples from the Basse Côte were devoid of nitrite. On the other hand, those from Korhogo revealed the presence of nitrite. Also, the borehole waters of the regions of the Basse Côte and Korhogo contain relatively high nitrate contents, presumably due to anthropometric activity. Overall, our study on the quality of drinking water showed that the waters analyzed are in compliance with international standards and safe for consumption.
文摘The nitrate reduction reaction(NtRR)has been demonstrated to be a promising way for obtaining ammonia(NH_(3))by converting NO3-to NH3.Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostructured nanowires(Co_(3)O_(4)/GDY NWs)by a simple two-step process including the synthesis of Co_(3)O_(4)NWs and the following growth of GDY using hex-aethynylbenzene as the precursor at 110°C for 10 h.Detailed scanning electron microscopy,high resolution transmission electron microscopy,X-ray photoelectron spectroscopy,and Raman characterization confirmed the synthesis of a Co_(3)O_(4)/GDY heterointerface with the formation of sp-C-Co bonds at the interface and incomplete charge transfer between GDY and Co,which provide a con-tinuous supply of electrons for the catalytic reaction and ensure a rapid NtRR.Because of these advantages,Co_(3)O_(4)/GDY NWs had an excellent NtRR performance with a high NH3 yield rate(YNH3)of 0.78 mmol h^(-1)cm^(-2)and a Faraday efficiency(FE)of 92.45%at-1.05 V(vs.RHE).This work provides a general approach for synthesizing heterostructures that can drive high-performance ammo-nia production from wastewater under ambient conditions.
基金the support from Key R&D Program of Zhejiang(2024SSYS0064)the Fundamental Research Funds for the Central Universities (2022ZFJH04)。
文摘The electrocatalytic nitrate reduction reaction (NO_(3)RR) powered by renewable energy offers a promising approach for simultaneously reutilization of nitrate and synthesizing high-value products.Nevertheless,theoretical understanding of reaction mechanism was relative illusive,which is indispensable to rationally design of efficient catalysts.Besides,tuning the reaction microenvironment along with the scale-up device development is essential to promote the industrial deployment of electrocatalytic nitrate conversion,while relative research was overlooked.In this regard,recent advances in ammonia synthesis are firstly summarized,including the identification of active sites,exploration of the underlying reaction mechanisms,electrolyzer design and technical-economic analysis.Furthermore,electrocatalytic C–N coupling based on NO_(3)RR to produce higher-value products such as urea and amino acids are also reviewed,to extend the application potential and economic feasibility.Finally,we highlight the existing challenges and the demand of future research for NO_(3)RR.This review anticipates to provide insights into synthesis of high-value products via NO_(3)RR,bridging the gap from laboratory research to industrial fabrication.
基金supported by the National Natural Science Foundation of China(22005274 and 21975225)the Postdoctoral Science Foundation of China(2020M672261)。
文摘Lithium metal batteries(LMBs)have received increasing attention due to the high energy density.However,the practical application of LMBs is limited due to the incompatibility of ester electrolytes.Transition metal(TM)nitrates have been reported as effective additives in ester electrolyte to improve the stability of lithium anode.Unfortunately,the nitrates are restricted to use due to their poor solubility.We find that the nitrates containing crystal water have high solubility in ester electrolytes.Considering that most TM nitrates contain crystal water and the crystal water can be used as a perfect solubilizer of nitrates,thus,the method is of universality and facile without introducing any solubilizing agent.Herein,In(NO_(3))_(3.6)H_(2)O is chosen as one typical case with increased solubility up to 0.2 M compared with In(NO_(3))_(3)which hardly dissolves in ester electrolyte.The additive promotes the rapid and stable formation of the solid electrolyte interface(SEI),which effectively inhibits the lithium dendrites formation.Moreover,the induced cathode electrolyte interface(CEI)maintains the structural stability of Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811).As a result,the electrochemical performance of Li|NCM811 cell is obviously improved.Our study provides a new idea for dissolving nitrates in ester electrolytes and discloses the synergistic function of TM-ions.
文摘A tripodal ligand, tris{2 [N (pyridine methanoyl)amino]ethyl}amine(L), and its complexes with rare earth nitrates were synthesized. These new complexes with the general formula of Ln(NO 3) 3·L·6H 2O(where Ln=La, Nd, Eu, Tb, Y) were characterized by elemental analysis, IR spectra, thermal analysis, 1 H NMR spectra, molar conductivity and luminescent spectra. All the complexes are stable in air and their conductances in acetonitrile solution lie in the range of 142～150 S·cm 2·mol -1 , indicating 1∶1 type electrolytes. The IR and 1H NMR spectra of the ligand and its complexes show that all the C=O groups take part in coordination to the metal ions. The thermal behaviour of Eu complex shows that the weight losses at 75～120 ℃ and 120～210 ℃ correspond to the loss of four lattice water molecules and that of two coordinated water molecules, respectively. The luminescent spectra of the complexes of Eu(Ⅲ) and Tb(Ⅲ) were investigated in methanol.
文摘Eight new complexes with the general formula of RE(Gly)(NO_3)_3(phen)_2·3H_2O (RE=La, Ce, Pr, Nd, Gd, Sm, Er, Y) were synthesized and characterized by elemental analysis, molar conductivity, IR spectra, UV spectra and thermal analysis. All the complexes are stable in air and their conductance values in acetonitrile lie in the range of 204.1～239.4 S·cm2·mol -1, indicating 1∶2 type electrolytes. The IR shows that all the COO of glycine and oxygen atom of NO_3- take part in the coordination to the RE ions. The thermal behavior of La complex shows that the weight losses at 75～120 ℃ and 145～170 ℃ correspond to the loss of two lattice water molecules and one coordinated water molecules, respectively.
文摘Nine new solid complexes of Mn(Ⅱ),Co(Ⅱ),Cu(Ⅱ),Zn(Ⅱ.),Ag(Ⅰ) nitrates with 4',5'-dibromobenzo-15—crown—5(L_A),Ag(Ⅰ),Cd(Ⅱ)nitrates with tetrabromodibenzo—18—crown—6(L_B)and Cu(Ⅱ), Ag(Ⅰ) nitrates with 4'—bromo—5'—nitrobenzo—15—crown-5(L_c),having the compositions of M(NO_2)_2·L·nH_2O(M=Mn,Co, Zn,L=L_A,n=2;M=Cu,L=L_A,n=1.5; M=Cd, L=L_B,n=0; M=Cu,L=Lc,n=2) and AgNO_·L·nCH_3CN(L=LA,n=0; L=L_B,n=1; L=Lc,n=1/2) have been synthesized in nonaqueous solvent. All the isolated complexes have been characterized by elementary analysis, IR and UV spectra, differential thermal and thermogravimetric analysis, X—ray powder diffraction analysis, molar conductance and measuremends of solubility in some general solvents.
基金financially supported by the Liao Ning Revitalization Talents Program(No.XLYC1907185)the Fundamental Research Funds for the Central Universities(Nos.N182505040 and N2025011)。
文摘The emissions of NO_(2)and HONO from the KNO_(3)photolysis in the presence of TiO_(2)were measured using a round-shape reactor coupled to a NO_(x)analyzer.TiO_(2)played important roles in the emission flux density of NO_(2)(R_(NO_(2)))and HONO(R HONO),depending on crystal structures and mass ratios of TiO_(2).R NO_(2)and R HONO significantly decreased with increasing the rutile and anatase mass ratios from 0 to 8 and 0.5 wt.%,respectively.Nevertheless,with further increasing the anatase mass ratio to 8 wt.%,there was an increase in R_(NO_(2))and R HONO.R NO_(2)on KNO_(3)/TiO_(2)/SiO_(2)had positive correlation with the KNO_(3)mass(1–20 wt.%),irradiation intensity(80–400 W/m^(2))and temperature(278–308 K),while it had the maximum value at the relative humidity(RH)of 55%.R HONO on KNO_(3)/TiO_(2)/SiO_(2)slightly varied with the KNO_(3)mass and temperature,whereas it increased with the irradiation intensity and RH.In addition,the mechanism for NO_(2)and HONO emissions from the nitrates photolysis and atmospheric implications were discussed.
文摘Mixed rare earth nitrates （REi（NO3）3） in the aqueous solution was mixed with tri-n-butyl phosphate （TBP, （n-C4H9O）3PO） dissolved in kerosene for the formation of their corresponding complexes （REi（NO3）3·ni（n-C4H9O）3PO） at 303 K. The effects of initial concentrations of both TBP and mixed rare earth nitrates on the equilibrium constants of their complex formations were investigated. The complexes were formed almost immediately after mixing. The simultaneous formations reached their chemical equilibria within a few minutes by shaking the mixture at 200 r/min. The chemical equilibrium constants of the complex formations were independent of the initial TBP concentrations. However, they were decreased by reducing the concentration of REi（NO3）3. All equilibrium constants of the simultaneous complex formations were less than 0.7, while the average molar ratio of TBP to REi（NO3）3 of the complexes varied between 1.0 and 1.6. The chemical equilibrium constant for the formation of La（NO3）3·（n-C4H9O）3PO was 0.09, while that of Dy（NO3）3·（n-C4H9O）3PO was 0.68. The ascending sequence of chemical equilibrium constants for the simultaneous formations was La, Ce, Pr, Nd, Eu, Y, Sm, Gd, and Dy.
文摘Three new solid complexes of macrocyclic polyether ligand 2, 2'-dinitro-4, 5, 4', 5'bis-(15- crown-5)-dihenzo disulfide(L) with trivalent rare earth nitrates having composition of RE(NO_3)_3·L ·6H_2O(RE=Ce, Pr, Nd) have been synthesized in acetonitrile. All the isolated complexes have been characterized by elementary analysis, IR and UV spectra, differential thermal and thermogravimetric analysis, X-ray powder diffraction analysis, molar conductance and measurements of solubility in some general solvents.
文摘Within the framework of the contract of Sourou River, a survey of the groundwater quality was performed through 7 campaigns of water sampling and analysis from 2006 till 2012. The water samples resulted from 23 drillings and 9 wells located in the Sourou Valley. Among the analyzed physico-chemical parameters, the nitrates concentrations observed were worrisome. Out of 32 water sources, 14 (44%) supplied a nitrates content superior to the WHO threshold value for drinking water (50 mg NO3/L). Very high concentrations, superior to 500 mg NO3/L with a peak in 860 mg/L, were observed. Given the important variations observed from a sampling point to another, a generalized contamination of the total aquifer was not possible. An individual diagnosis allowed to identify the possible causes of this degradation. Several sources of contamination, in connection with the anthropological activities, were observed near the water facilities (drillings/wells): animal and human wild defecation, presence of nontight latrines, solid waste, wastewater discharges. It is also advisable to wonder about the impact of the dynamite use for digging wells, this one being able to leave nitrates in the water. With regard to the intensive use of water from the strongly contaminated wells and drillings by the rural populations of Sourou, implementing protection areas within which would be eliminated the sources of contamination in addition to health education among populations could improve the situation. Care should also be taken in the use of nitrates explosives for digging new wells or drillings.
文摘Six new solid complexes of macrocyclic polyether ligand 4′-bromo-5′-nitrobenzo-15-crown-5(L)with Uivalent rare earth nitrates having composition of RE(NO_3)_3·L·mCH_3CN·nH_2O(RE=L_a--Nd,m=n=0, RE=Sm,Bu,m=0.1,n=1,4)have been synthesized in acetonitrile or acetone.All the isolated complexes have been char- acterized by elementary analysis,IR and UV spectra,differential thermal and thermogravimetric analysis,X-ray powder diffraction analysis,molar conductance and measurementa of solubility in some general solventa.It shows that coordination number of the rare earth cation in the complexes of La,Ce,Pr and Nd nitrate is eleven.
基金supported by the National Natural Science Foundation of China (51862024,51772140,51962023)the Natural Science Foundation of Jiangxi Province (20171ACB21033,20192ACBL21047)。
文摘N-containing Ce_(2)Si_(2.5)Al_(0.5)O_(3.5)N_(3.5)(CeSiAlON) melilite was synthesized at 1550 and 1600℃ for 5 h from CeO_(2),Si,Al,and Al_(2)O_(3) in nitrogen by using Y_(2)O_(3) and transition-metal nitrates(Co(NO_(3))_(2)·6 H_(2) O and Ni(NO_(3))_(2)·6 H_(2)O) as additives.The effects of Y_(2)O_(3) and transition-metal nitrates on the phase,microstructures and photoluminescence properties of CeSiAlON melilite were studied.The incorporation of Y_(2)O_(3) can promote the reaction of raw materials to a low degree,and results in a unit cell shrinkage of CeSiAlON due to the smaller radius of Y atom than that of Ce atom.The transition-metal nitrates can accelerate the reaction clearly and facilitate the formation of CeSiAlON fibers.The photoluminescence(PL) properties of CeSiAlON melilite presents a board violet emission band because of the 5 d-4 f transitions of Ce^(3+),and the additives can enhance the PL emission intensities of specimen significantly.
文摘The interactions of 2,2'-bipyridyl with the lanthanide nitrates were studied and complexes of the formula Ln(NO_8)_8(bipy)_8 were isolated from water -ethanol mixed solvent.The complexes were characterized by elemental analysis, conductivity measurments,IR spectra and DAT-TG analysis.
文摘This paper presents results of nitrites and nitrates determination in two types of baby foods： commercial products in jars and their homemade conventional counterparts. Nitrites levels in all analyzed samples were below of the detection limit （〈 0.9 mg/kg） of applied spectrophotometric method with Griess reagent. Nitrates contents in commercial products ranged： 9.1-38.1 mg/kg while in homemade baby foods levels between 26.6 mg/kg and 118.8 mg/kg were obtained. All the contents of nitrates were lower than the EU legislation maximum limit （200 mg/kg）. Comparison of each type of commercial product with its homemade counterpart baby food evidenced significant differences （p 〈 0.05） in average nitrates levels in favor of the first type. Apart from determining and comparing the levels of nitrates in the baby food samples also risk assessment for an average 6-months old infant to nitrates exposure was conducted. The estimated nitrates intake with a typical portion of 200g of baby food ranged between 6% and 25.7% of acceptable daily intake for commercial and from 18.0% to 80.3% for homemade ones.
文摘Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.
文摘Objective: To investigate the protective effect of nitrates postconditioning on myocardial ischemia-reperfusion injury and whether it plays a regulatory role in TNF-α in patients with STEMI during PCI. Methods: Patients with STEMI who underwent PCI were selected, except for obvious anemia, head trauma, cerebral hemorrhage, hypotension (systolic blood pressure less than 90 mmHg), and patients with autoimmune diseases, all kinds of acute and chronic infections and malignant tumors. They were randomly divided into PCI standardized treatment group and isosorbide dinitrate postconditioning during PCI group. The concentrations of cTnI and TNF-α in serum were detected by ELISA method in each group before PCI and after 2 hours, 1 day, 4 days and 7 days of PCI. Results: 1) There were no statistically significant differences in sex, age, smoking history, diabetes, hypertension and blood lipid abnormality in two groups. 2) Before operation, the concentration of cTnI in two groups was not statistically significant. The concentration of cTnI in the experimental group was lower than that of the control group after 4 days and 7 days of PCI, and P α in two groups before operation. The concentration of TNF-α in the experimental group was lower than that in the control group after 1 day, 4 days and 7 days of PCI, and P α in two groups was both in 1 day after operation, and the peak level of the experimental group and the level of each time after the operation were lower than that of the control group. Conclusion: Nitrates postconditioning during PCI in patients with STEMI has a protective effect on myocardial ischemia-reperfusion injury. Nitrates postconditioning has an effect to reduce the level of TNF-α of patients with STEMI after PCI treatment, and may have the mechanism of alleviating the inflammatory response after myocardial ischemia and reperfusion.
基金Project supported by the Ministry of Agriculture, China (No. 95-17-03-01).
文摘The effects of different chemical fertilizer combinations (N, P and K) oncrop yield, N uptake and nitrate distribution and accumulation to a depth of 100 cm were studied ina cinnamon fluvo-aquic soil profile (Beijing) with a continuous winter wheat-summer maize croppingsystem for nine years. The experiment consisted of 7 treatments: no fertilizer control (CK); Nalone, N in combination with K (NK), P (NP), and P and K (NPK and N1PK); and P and K in combinationwithout N (PK). The rate of N was 150 kg ha^(-1) for the N treatments except Treatment N1PK withhigher N rate (195 kg ha^(-1)), and the rates of P (P_2O_5) and K (K2O) were 75 and 37.5 kg ha^(-1),respectively. The applications of N combined with P and K (NK, NP and NPK) resulted in higher cropyields than a single application of N. The yields followed the order: NPK > NP > N1PK > PK > NK > N> CK for winter wheat, and NPK > N1PK > NP > NK > N > PK > CK for summer maize. Supplement of N withP or K, or both P and K resulted in a higher average N uptake of the two crops, which was in adecreasing order NPK > NP > N1PK > NK > N > PK > CK. The combinations also increased apparent Nrecovery more than N alone and CK. The nitrate content in the profile was thus reduced more in thecombination treatments. The nitrate accumulation in the soil profiles followed the order: N > NK >N1PK > NPK > NP > CK > PK. Higher N uptake by the adequately fertilized crops (Treatment NPK)reduced nitrate accumulation in the profile and thus reduced nitrate leaching. The optimum N:P:Kratio was thus of paramount importance in increasing yields and N uptake of crops and reducingnitrate leaching losses.
基金the National Key Basic Research Program of China (973program)，a key project of the Shandong Provincial Environmental Protection Department，the Niche Area Development Scheme of the Hong Kong Polytechnic University，the Hong Kong Research Grants Council，the central level,scientific research institutes for basic R & D special fund business
文摘For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality in Beijing. To investigate the effects of SO2 and NOx reductions on the particulate sulfate and nitrate concentrations as well as their size distributions, size-segregated aerosol samples were collected using micro-orifice uniform deposit impactors （MOUDIs） at urban and downwind rural sites in Beijing before and after full-scale controls. During the sampling period, the mass concentrations of fine particles （PMI.s） at the urban and rural sites were 94.0 and 85.9 p.g m-3, respectively. More than 90% of the sulfates and 60% of nitrates formed as fine particles. Benefiting from the advantageous meteorological conditions and the source controls, sulfates were observed in rather low concentrations and primarily in condensation mode during the Olympics. The effects of the control measures were separately analyzed for the northerly and the southerly air-mass-dominated days to account for any bias. After the control measures were implemented, PM, sulfates, and nitrates were significantly reduced when the northerly air masses prevailed, with a higher percentage of reduction in larger particles. The droplet mode particles, which dominated the sulfates and nitrates before the controls were implemented, were remarkably reduced in mass concentration after the control measures were implemented. Nevertheless, when the polluted southerly air masses prevailed, the local source control measures in Beijing did not effectively reduce the ambient sulfate concentration due to the enormous regional contribution from the North China Plain.
文摘In the present study, we investigated the performance of clay mineral originated from a dam situated in Morocco (Agadir city), as natural, low-cost, alternative and eco-friendly adsorbent for removal of nitrates ions from aqueous solution within a batch process. The clay was characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Dispersive Energy of Spectroscopy (EDS), Fourier Transform Infrared (FTIR) and surface area analysis (BET). The effects of various experimental parameters are examined such as contact time, initial concentration of pollutant, adsorbent mass and solution pH. The removal of nitrate was 71.89% at natural pH (pH = 5.1) using 1 g/l of adsorbent in 500 ml of nitrate solution having initial concentration of 300 mg/l (effect of contact time). Adsorption kinetic study revealed that the adsorption process followed first order kinetic. Theoretical correlation of the experimental equilibrium adsorption data for the Nitrate-New Clay system was properly explained by the Langmuir isotherm model. The maximum adsorption capacity was Qm, exp = 244.06 mg/g at 20℃ and at natural pH (with Qm, cal = 250 mg/g). An increase in adsorbent dosage increased the percent removal of nitrate, R = 1 g/l was considered as optimum dose and was used for further study. The pH heavily affected the adsorption capacity, and the percentage removal was found to decrease with increase in pH. The obtained results indicated that this New Clay (NC) was very good adsorbent for NO3-, interesting alternative material with respect to more costly adsorbent used, and could be used as a highly efficient adsorbent for the separation of nitrate from drinking or waste water.
