Biobased Furfurylated Poplar Wood for Flame-Retardant Modification with Boric Acid and Ammonium Dihydrogen Phosphate

Furfurylated wood exhibits excellent dimensional stability and corrosion resistance,making it a promising material for constructing buildings,but it is highly flammable.Herein,flame-retardant furfurylated poplar wood was produced via a two-step process utilizing boric acid(BA)and ammonium dihydrogen phosphate(ADP)as flame-retardant components,and biomass-derived furfuryl alcohol(FA)as a modifier.The acidity of BA and ADP allowed them to catalyze the polymerization of FA,which formed a cross-linked network that immobilized BA and ADP inside the wood.The addition of BA/ADP substantially delayed the time to ignition from 10 to 385 s and reduced the total heat release and total smoke release by 58.75%and 77.31%,respectively.Analysis of the pyrolysis process showed that the decomposition products of BA and ADP protected the underlying furfurylated wood and diluted combustible gases.This method significantly improved the fire retardancy and smokeless properties of furfurylated wood,providing promising prospects for its application as an engineering material.

Study of the Effect of Acetic Acid and Phosphate on Copper Corrosion by Immersion Tests

It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and countermeasures were needed. Therefore, we studied the copper corrosion caused by acetic acid. The present work investigated the relationship between the corrosion form of copper and acetic acid concentration using phosphorous-deoxidized copper, and reported that hemispherical corrosion was observed at acetic acid concentrations of 0.01 to 1 vol.% (0.002 to 0.2 mol·L-1) in the immersion test. In this study, the effects of acetic acid and phosphate on copper corrosion were examined using oxygen-free copper in immersion tests. The results suggested that different concentrations of phosphate in acetic acid solutions and the presence or absence of acetic acid and phosphate affected the corrosion of copper, resulting in different corrosion forms and corrosion progress.

Calcium-Magnesium Ca/Mg Ratios and Their Agronomic Implications for the Optimization of Phosphate Fertilization in Rainfed Rice Farming on Acidic Ferralsol in the Forest Zone of Ivory Coast

This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha−1) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha−1) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha−1 of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha−1) and potassium (K) (50 kg KCl ha−1) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha−1 for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha−1, 34 kg Mg ha−1 in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha−1, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.

Phosphorus release from phosphate rock and iron phosphate by low-molecular-weight organic acids

Low-molecular-weight(LMW) organic acids widely exist in soils, particularly in the rhizosphere. A series of batch experiments were carried out to investigate the phosphorus release from rock phosphate and iron phosphate by low-molecular-weight organic acids. Results showed that citric acid had the highest capacity to solubilize P from both rock and iron phosphate. P solubilization from rock phosphate and iron phosphate resulted in net proton consumption. P release from rock phosphate was positively correlated with the p K _a values. P release from iron phosphate was positively correlated with Fe-organic acid stability constants except for aromatic acids, but was not correlated with p K _a. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearly. Addition of phenolic compounds further increased the P release from iron phosphate. Initial solution pH had much more substantial effect on P release from rock phosphate than from iron phosphate.

Arsenic removal from contaminated soil using phosphoric acid and phosphate

Laboratory batch experiments were conducted to study arsenic （As） removal from a naturally contaminated soil using phosphoric acid （H3PO4） and potassium dihydrogen phosphate （KHEPO4）. Both H3PO4 and KHEPO4 proved to reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L. At the same time, acidification of soil and dissolution of soil components （Ca, Mg, and Si） resulted from using these two extractants, especially H3PO4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions （PO4^3-）. The function of H3PO4 as an acid to dissolve soil components had little effects on As removal. KH2PO4 almost removed as much As as H3PO4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 rain, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich model best described the kinetic data of As removal among the four models used in the kinetic study.

Adsorption mechanism of mixed salicylhydroxamic acid and tributyl phosphate collectors in fine cassiterite electro-flotation system

Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation mechanism of the fine cassiterite was investigated by adsorbance determination,electrophoretic mobility measurements and Fourier transform infra-red(FT-IR) spectrum checking.Results of the flotation experiments show that with SHA as a collector,the collecting performance is remarkably impacted by the pulp pH value as the floatability of cassiterite varies sharply when the pH changes,and flotation with SHA gives distinct maximum at about pH 6.5.Additionally,the floatability of cassiterite is determined by using SHA and TBP as collectors.The range of pulp pH for good floatability is broadened in the presence of TBP as auxiliary collector,and the utilization of TBP improves the recovery of cassiterite modestly.Moreover,the optimum pH value for cassiterite flotation is associated with adsorbance.The results of FT-IR spectrum and the electrophoretic mobility measurements indicate that the adsorption interaction between the collectors and the cassiterite is dominantly a kind of chemical bonding in the form of one or two cycle chelate rings due to the coordination of carbonyl group,hydroxamate and P=O group to the metal tin atoms,where the oxygen atoms contained in carbonyl group,hydroxamate and P=O group of the polar groups have the stereo conditions to form five-membered rings.In addition,the adsorption interactions of SHA and TBP on the surfaces of cassiterite are also dominated by means of hydrogen bonds.

Extraction of cerium(Ⅳ) using tributyl phosphate impregnated resin from nitric acid medium

Tributyl phosphate （TBP） solvent was used for impregnation into Amberlite XAD-16 nonionic polymeric resin beads using the wet method to prepare solvent impregnated resin （SIR）. Undiluted TBP in a ratio to the resin support （volume to mass） of 6.0 at room temperature （RT） in 24 h was impregnated the resin with a mass ratio of 1.944, while the prepared gross sample of SIR at the ratio of solvent to resin of 3.0 was impregnated with a mass ratio of 1.88. Cerium（Ⅳ） oxide concentrate, prepared from crude Egyptian monazite sand, containing 37% cerium, 1.6% thorium and about 40% the other trivalent rare earth oxides, was used to prepare cerium（Ⅳ） nitrate solution for extraction using the prepared SIR. The impregnated resin was satisfactory for Ce（Ⅳ） extraction from nitric acid medium at room temperature. Cerium loading capacity of the impregnated resin reached 95.6% of the calculated theoretical capacity （173 g/kg （Ce/SIR）） under the conditions of 51.57 g/L cerium and 2.48 g/L thorium, 5.0 mol/L free nitric acid, solution to resin ratio of 10.0 and contacting the phases for 5.0 min. The loading capacity reached 98.75% when cerium concentration was increased to 91.43 g/L under the same conditions.

Synthesis of Mesoporous, Nanocrystalline Lanthanum Phosphate in the Presence of Citric Acid and Stearic Acid

Lanthanum phosphate was prepared in the presence of citric acid and stearic acid under methanolic conditions at pH 4.5 and pH 7, respectively. The samples obtained were intensively characterized using X-ray diffraction, nitrogen adsorption-desorption isotherm study, transmission electron microscopy （TEM）, thermal gravimetric and differential thermal analysis, and Fourier transform infrared （FTIR） analysis . The as-synthesized samples prepared at pH 4.5 showed lamellar mesostruroned form with high crystallinity. Results showed that the pore size and pore volume changed when the materials were prepared under different pH conditions. Morphology of the samples was observed by using TEM, which showed that the samples possessed relatively small particles closely packed together. The as-synthesized samples were investigated using FTIR, and the mesopore formation mechanism was discussed.

Humic acid-mediated visible-light degradation of phenol on phosphate-modified and Nafion-modified TiO_2 surfaces

Although humic acid(HA)can inhibit TiO2photocatalysis,it can sensitize TiO2and induce significant visible‐light(VL)activity in phenol degradation.This favorable effect of HA was negligible on phosphate‐modified TiO2(P‐TiO2),but significantly stronger on Nafion‐modified TiO2(Nf‐TiO2).The reaction rate constants for phenol degradation on Nf‐TiO2increased from(0.003±0.001)to(0.025±0.003)min?1when the reaction was performed in the presence of20mg/L HA.The different effects of HA on P‐TiO2and Nf‐TiO2photocatalysis cannot be attributed to adsorption changes,because the adsorption capacities of P‐TiO2and Nf‐TiO2were only slightly lower than that of TiO2at an initial HA concentration of20mg/mL.Scavenger tests,electron paramagnetic resonance spectroscopy,and H2O2detection were taken to understand the low VL activity of the P‐TiO2/HA suspension.The main active species for phenol degradation in the TiO2and Nf‐TiO2suspensions were superoxide radicals.There were negligible amounts of superoxide radicals in the P‐TiO2/HA suspension,possibly because a direct four‐electron oxygen reduction reaction occurred.The better VL activity of Nf‐TiO2was rationalized on the basis of Mott–Schottky and electrochemical impedance plots.Nafion modification resulted in cathodic shifts of the energy band positions,increased electron density,and less resistance to electron transfer across the interface between TiO2and electrolytes.All these factors facilitated electron transfer and improved the production of active species.Phosphate modification therefore did not improve the VL response of HA sensitized TiO2,and low concentrations of HA can facilitate VL photocatalytic degradation of organic pollutants on Nafion surface‐modified TiO2.

Study of vascular smooth muscle cell calcification induced by hyperphosphate and intervented by phosphonoformic acid

Objective： To evaluate the effects of different concentrations of phosphate on calcium deposition and osteocalcin level in cultured bovine aortic smooth muscle cell, investigate the mechanism of hyperphosphatemia to evoke calcification of vascular smooth muscle cell and observe the effects of phosphonoformic acid（PFA） in different concentrations on vascular calcification. Methods： The bovine aortic smooth muscle cells （BASMC） were cultured.Calcium deposition and the expression of osteocalcin of BASMC in different concentrations of phosphate （1.5 mmol/L and 2.0 mmol/L） and PFA were determined by o-cresolphthalein complexone and radioimmunity methods, respectively. Osteocalcin mRNA expressions were determined by RT-PCR. Results： After six or nine days of BASMC cultured, the calcium deposition in Pi 2.0 mmol/L group was more than that in Pi 1.5 mmol/L group[（77.187 ± 11.692） lag/（mg · protein） vs（25.768 ± 1.750）lag/（mg · protein）, P 〈 0.01 and（125.399 ± 16.677）lag/（mg · protein） vs（29.046 ± 2.635）lag/（mg · protein）, P 〈 0.01 respectively]. The calcium deposition was dependent on time and dosage of phosphate treatment. After 72 h culture the osteocalcin in Pi 2.0 mmol/L group was more than that in Pi 1.5 mmol/L grouplin supematant,（1.503 ± 10^-2 ± 2.601 × 10^-3）ng/（ lag o protein） vs（2.981 × 10-3 ± 8.382 × 10-34）ng/（ lag · protein）, P 〈 0.001], the same was found in osteocalcin mRNA expression[OC/GAPDH, （1.906 ± 0.132） vs（0.748 ± 0.037）, P〈 0.001]. Compared to Pi 1.5mmol/L group,bovine smooth muscle cells（BSMC） cultured in media containing Pi 2.0 mmol/L phosphate levels increased calcium deposition[On day 6,（77.187 ± 11.692） la g/（mg · protein） vs （25.768 ±1.750） la g/（mg · protein）, P 〈 0.001]. Elevated phosphate treatment of BSMCs also enhanced the expression of the osteoblastic differentiation marker osteocalcin[On day 3, Pi 2.0 mmol/L group vs Pi 1.5mmol/L group,（1.503 × 10^-2 ± 2.601 × 10^-3 ）ng/（ lag · protein） vs（2.981× 10^-3 ± 8.382 × 10^-4）ng/（ μg · protein）, P 〈 0.001]. PFA decreased ciacium deposition and osteocalcin expression statistically[Pi 2.0 mmol/L±PFA1.0 mmol/L group vs Pi 2.0mmol/L group, ciacium deposition, （37.729 ± 5.899） lμg/（mg · protein） vs （77.187 ± 11.692）μg/（mg ·protein）, P 〈 0.001]; Osteocalcin in supernatant, （4.529 ± 10^-3 ± 1.250 × 10^-3）ng/（ μ g · protein） vs（1.503 × 10^-2 ± 2.601 × 10^-3） ng/（ μg · protein）, P〈 0.001; osteocalcin mRNA expression, OC/GAPDH, （0.642 ± 0.092） v s （1.89 ± 0.165）, P 〈 0.01]. Conclusion： Hyperphosphate may directly promote calcium deposition and the osteocalcin expression of B ASMCs. It may be a new explanation for the phenomenon of vascular calcification in hyperphosphatemic conditions. Hyperphosphatemia is an independent factor to stimulate vascular calcification. PFA can inhibit calcium deposition and osteocalcin expression induced by elevated phosphate.PFA may be a new medicine to treat vascular calcification induced by elevated phosphate.

Application of Ground Phosphate Rock to Dimmish the Effects of Simulated Acid Rain on Soil Properties

The effects of simulated acid rain retained in soil on the properties of acid soil and its diminishing by application of ground phosphate rock were investigated by using the sorption method. Results show as follows: (1) For yellow brown soil, the effect of simulated acid rain on the properties of soil with a pH value of 5.9 was relatively small, except a great quantity of acid rain deposited on it. (2) For red soil, the effect of simulated acid rain on the properties of soil was significant. With the increase of the amount of acid deposition, the pH value of soil was declined, but the contents of exchangeable H+, Al3+ and Mn2+ and the amount of SO42- retention were increased. (3) Many properties of acid soils could be improved by applying ground phosphate rock. For example, pH value of soils and the amounts of available P and exchangeable Ca2+ and Mg2+ were increased, and the amounts of exchangeable H+ and Al3+ and SO42- retained was reduced. The application of ground posphate rock could effctively dimmish the pollution of acid rain to soil.

Convenient synthesis of β-allenic α-difluoromethylenephosphonic acid monoesters:Potential synthons for cyclic phosphate mimics

β-Allenic α-difluoromethylenephosphonic acid monoesters were prepared under mild conditions for the first time by hydrolyzing the corresponding diethyl phosphonates in aqueous sodium hydroxide solution.

Modeling and Optimization of Two Clays Acidic Activation for Phosphate Ions Removal in Aqueous Solution by Response Surface Methodology

This work deals with phosphate ions removal in aqueous solution by adsorption carried out using two clays, both in activated form. One, non-swelling clay, rich in kaolinite, is associated with illite and quartz. The other, swelling, richer in montmorillonite, is associated with kaolinite, illite and quartz. Seven factors including these two clays were taken into account in a series of experimental designs in order to model and optimize the acidic activation process favoring a better phosphate removal. In addition to the choice of clay nature, the study was also interested in the identification of the mineral acid, between hydrochloric acid and sulfuric acid, which would promote this acidic activation. Response Surface Methodology (RSM) was used for this purpose by sequentially applying Plackett and Burman Design and Full Factorial Design (FD) for screening. Then, a central composite design (CCD) was used for modeling the activation process. A mathematical surface model has been successfully established. Thus, the best acidic activation conditions were obtained by activating the montmorillonite clay with a 2N sulfuric acid solution, in an acid/clay mass ratio of 7.5 at 100°C for 16H. The phosphate removal maximum rate obtained was estimated at 89.32% ± 0.86%.

Ion-pair induced solvent extraction of lithium(Ⅰ)from acidic chloride solutions with tributyl phosphate

Lithium(Li)is an important energy metal in the 21st century.However,the selective recovery of Li is still a big challenge,especially from acidic solutions with multiple metal ions existence.Herein we report a new ion pair induced mechanism for selectively extracting Li^(+)from acidic chloride solutions by tributyl phosphate(TBP).It is shown that the acidity and the chloride ions in the aqueous phase have great effects on the extraction of Li^(+).The FT-IR,UV-Vis and ESI-MS experiments provide solid evidence for the formation of ion-pair complex[Li(TBP)_n(H_(2)O)_(m)]^(+)[FeCl_(4)]^(-)(n-1,2,3;m-0,1)in the organic phase,which brings about the effective and efficient extraction of Li^(+).This mechanism can overcome the Hofmeister bias and allow for the selective extraction of Li^(+) from the extremely hydrophilic chlorides.It has also been proved that the loaded Li in TBP can be effectively stripped by concentrated HCl solution with a Li/Fe separation factor>500.The understanding of the ion-pair transport mechanism is helpful for optimizing the recovery process or further advancing more efficient recovery techniques for Li from acidic liquor.

Jebel Kurun Phosphate Rock Characteristics and Technical Viability to Produce Phosphoric Acid

The technical viability for utilizing Jebel Kurun phosphate reserve in Sudan for the production of a fertilizer grade phosphoric acid is assessed. Statistical analysis has been carried for 56 samples. Phosphate rock has been classified into three main types and then the number of samples representing each type has been identified. Average values for phosphorus pentoxide is 19% and for uranium is 81.47 ppm. The most abundant elements are silicon, aluminum, phosphorus, calcium and iron. Aluminophosphate ore (CaO% ≤ 12%, Al2O3% ≥ 20%, P2O5% ≥ 18%) is represented by 55.36% of sampled phosphate rock. This type can be used to produce phosphoric acid when P2O5 > 30%. Apatite rock including aluminophosphate CaO% ≥ 25%, Al2O3% ≤ 10%, P2O5% ≥ 20%, 12% ≤ SiO2 ≤ 35% is represented by 1.79% of sampled phosphate rock, this type can be used to produce phosphoric acid when it can meet the requirements of (CaO% ≥ 30%, Al2O3% ≤ 7%, P2O5% ≥ 25%, SiO2% ≤ 30%). Silica ore including phosphorus (SiO2% ≥ 40%, P2O5% ≤ 10%) is represented by 16.07% of sampled phosphate rock and Iron ore including phosphorus (Fe2O3% ≥ 20%, P2O5% ≤ 10%) is represented by 5.36% of samples. Both types cannot be used to produce phosphoric acid. The statistical distribution of P2O5 in the size fractions for a core drilled samples is required.

Intensified reactive extraction of 4-hydroxypyridine with di(2-ethylhexyl) phosphoric acid in 1-octanol by using tributyl phosphate

The efficient separation of amphoteric organic compounds from dilute solutions is of great importance in the industrial field. In the present work, the reactive extractions of 4-hydroxypyridine(4-HP) with tributyl phosphate(TBP), di(2-ethylhexyl) phosphoric acid(D2EHPA) and TBP + D2EHPA dissolved in 1-octanol were investigated, respectively. The influences of the initial concentrations of TBP, D2EHPA and TBP + D2EHPA on distribution ratio(D) were discussed, as well as the reactive extraction mechanism were proposed. The obvious intensification effect was observed when the mixture of TBP and D2EHPA was used as extractant. The best extraction conditions were found to be of the molar ratio of D2EHPA and TBP at 2:1 and the equilibrium aqueous pH at 3.50-4.50. D values increased with the increase of the total concentration of TBP and D2EHPA in 1-octanol. Especially, the analysis on the extraction mechanisms clearly indicate(i) TBP in 1-octanol shows negligible reactive extraction toward 4-HP,(ii) D2EHPA in 1-octanol exhibits moderate extraction effect by forming 4-HP:D2EHPA(1:1) and 4-HP:2D2EHPA(1:2) type complexes, while(iii) D2EHPA in TBP/1-octanol demonstrates the maximum distribution ratio with the 4-HP:D2EHPA(1:1) type complex domination. The discussion provides new insights on the mechanism and opens a new way for the intensified extraction of amphoteric organic compounds by using the mixture of multiple extractants in the diluent.

Screening of genes of secreting acetic acid from Aspergillus niger H1 to improve phosphate solubilization

A primary cDNA library of Aspergillus niger H1 was constructed using the switching mechanism at the 5′ end of the RNA transcript（SMART） technique. A total of 169 clones exhibited halos when grown on tricalcium phosphate medium, and the H-46 clone displayed a clear halo. The full-length c DNA of the clone H-46 clone was 1 407 bp in length with a complete open reading frame（ORF） of 816 bp, and it encoded a protein that contained 272 amino acids. Multiple alignment analysis revealed a high degree of homology between the ORFs of the H-46 clone and the Bax inhibitor family（BI-1-like） proteins of other fungi. Acetic acid was secreted by Escherichia coli DH5α that express the BI-1-like gene. The level attained was 492.52 mg L^（-1）, which was associated with the release of 0.212 mg m L^（-1） of soluble phosphate at 28 h. These results showed that the heterologous expression of BI-1-like genes in Eschericha coli DH5α increased the secretion of acetic acid by altering the membrane permeability and enhancing the solubility of phosphate（P）.