Phosphoric Functional Groups Research Articles

Poultry litter physiochemical characterization based on production conditions for circular systems

Poultry litter is a useful product as a fertilizer, energy feedstock for thermochemical conversion, and a precursor for synthesis of adsorbents and catalysts. Detailed characterization of baseline properties is necessary for enhanced environmental and economic utilization of this valuable resource. Baseline physicochemical characterization was carried out at two broiler production facilities (Arkansas, PL1, and North Carolina, PL2). Greater concentrations of inorganic nitrogen, phosphorus, and potassium were obtained for PL1, suggesting greater nutrient value compared to PL2. PL2 had greater carbon content and water-holding capacity than PL1. X-ray photoelectron spectroscopy (XPS) of PL1 and PL2 indicated a similarity between litters in terms of the presence of carbon, nitrogen, and oxygen bonds. Both poultry litters had oxygen, nitrogen, sulfur, and phosphorous functional groups, as confirmed by infrared spectroscopy. Time of flight – secondary ion mass spectroscopy of negative ions also indicated similarity of the surface charge distribution between PL1 and PL2. Overall, poultry litters evaluated had similar surface chemistries, with nutrient composition varying based on rearing conditions, which has implications for downstream use in thermochemical conversion and other value-added products.

Experimental and computational study on the inhibitory effect of phytic acid on U(VI) biomineralization by Shewanella putrefaciens

Uranyl (UO22+) species with hexavalent U(VI) oxidation state is the most ubiquitous form of uranium in natural minerals, underground water, contaminated soils, and ocean. Interplay between bioorganic molecules and U(VI) is rather complicated due to its various complex configurations and reaction networks. In this study, the widely present phytic acid (IP6) is selected as a model organic molecule together with the bacteria Shewanella putrefaciens (S. putrefaciens, existing mainly in marine environments) to explore its role on U(VI) biomineralization. We found that phytic acid had a clear inhibition effect on the U(VI) removal of S. putrefaciens, with the absorption capacity dropped from 382.77 mg/g to 102.45 mg/g. Further Dialysis experiment suggested that phytic acid tended to chelate with U(VI) to form colloid polymer. Quantum-theoretical modeling confirmed that phytic acid bond strongly with uranyl ions, while calcium and magnesium ions could bind with phytic acid as well via ionic bonding, thus relieving the inhibition effect of phytic acid in the solution through breaking the hydrogen bonding network. XRD and SEM-EDS results showed that phytic acid could hinder the formation of mineralized body (Metanatroautunite [Na(UO2)(PO4)·3H2O]) and prefer to form amorphous material. Further FTIR and XPS data illustrated that the bacteria mainly interacted with U(VI) through phosphorous functional groups. This study presents detailed information for colloid formation between phytic acid and U(VI) as well as the critical role of Ca2+ and Mg2+ ions on the matrix of S. putrefaciens bacteria, combining with molecular-level microscopic understanding on the chemical behavior of U(VI) in the presence of inorganic and organic ions in soil and water.

Hardwood spent mushroom substrate–based activated biochar as a sustainable bioresource for removal of emerging pollutants from wastewater

Hardwood spent mushroom substrate was employed as a carbon precursor to prepare activated biochars using phosphoric acid (H3PO4) as chemical activator. The activation process was carried out using an impregnation ratio of 1 precursor:2 H3PO4; pyrolysis temperatures of 700, 800, and 900 °C; heating rate of 10 °C min−1; and treatment time of 1 h. The specific surface area (SSA) of the biochars reached 975, 1031, and 1215 m2 g−1 for the samples pyrolyzed at 700, 800, and 900 °C, respectively. The percentage of mesopores in their structures was 75.4%, 78.5%, and 82.3% for the samples pyrolyzed at 700, 800, and 900 °C, respectively. Chemical characterization of the biochars indicated disordered carbon structures with the presence of oxygen and phosphorous functional groups on their surfaces. The biochars were successfully tested to adsorb acetaminophen and treat two simulated pharmaceutical effluents composed of organic and inorganic compounds. The kinetic data from adsorption of acetaminophen were fitted to the Avrami fractional-order model, and the equilibrium data was well represented by the Liu isotherm model, attaining a maximum adsorption capacity of 236.8 mg g−1 for the biochar produced at 900 °C. The adsorption process suggests that the pore-filling mechanism mainly dominates the acetaminophen removal, although van der Walls forces are also involved. The biochar produced at 900 °C removed up to 84.7% of the contaminants in the simulated effluents. Regeneration tests using 0.1 M NaOH + 20% EtOH as eluent showed that the biochars could be reused; however, the adsorption capacity was reduced by approximately 50% after three adsorption–desorption cycles.

Fully phosphorylated 3D graphene oxide foam for the significantly enhanced U(VI) sequestration

Efficient sequestration of U(VI) from complex aqueous solution is of vital importance for environmental remediation. In this work, the fully phosphorylated graphene oxide foam (phos-GOF) was synthesized via a facile hydrothermal method and the as-prepared 3D phos-GOF was served as an adsorbent to capture U(VI) from aqueous solution. The introduction of abundant phosphorus-containing groups via phytic acid endows phos-GOF good hydrophilia and excellent affinity for U(VI). The adsorption performance of phos-GOF for U(VI) was carefully evaluated under different environments. phos-GOF shows rapid and high efficiency for U(VI) adsorption. The maximum adsorption capacity of phos-GOF for U(VI) is ∼483 mg/g, which is much higher than that of pristine graphene oxide foam (GOF). In addition, the spent 3D phos-GOF can be easily regenerated by a simple and low-cost desorption process using 0.02 mol/L HNO3. The interaction mechanism between phos-GOF and U(VI) is mainly attributed to the inner-sphere complexation between phosphoric functional groups and U(VI) based on a series of spectroscopic analyses. The 3D phos-GOF exhibits favorable sequestration performance towards U(VI) which can be used as a potential candidate in uranium-bearing wastewater treatment and disposal.

Removal of U(VI) from aqueous solution using phosphate functionalized bacterial cellulose as efficient adsorbent

Abstract In this study, phosphate functionalized bacterial cellulose with micro-fibrous structure was prepared, characterized and applied for U(VI) adsorption. The successful grafting of phosphoric functional groups was proved by the FTIR spectra and EDS analysis (P~4.15 wt%), and the porous structure was confirmed by SEM and BET analyses. Furthermore, the effect of initial pH, contact time, initial concentration, and temperature were studied. The as-prepared adsorbent showed a high adsorption capacity at wide pH range (4.0–8.0) and its maximum adsorption capacity was calculated to be 50.65 mg/g. This endothermic adsorption process conformed to the pseudo second-order kinetic model and the Elovich kinetic models and the Langmuir isothermal models. According to the FTIR and XPS analysis, an adsorption mechanism was tentatively proposed, mainly due to the interaction between U(VI) and phosphoric groups.

Preparation of amino-modified hydroxyapatite and its uranium adsorption properties

The amino-hydroxyapatite (HAP-NH2) was synthesized by grafted amino functional groups onto hydroxyapatite. The uranium adsorption performance of HAP-NH2 was studied under different conditions. The results indicated that HAP-NH2 possessed high adsorption capacity (96 mg g−1), wide pH values range (2–8) and fast adsorption rate (20 min). The adsorption kinetic and adsorption isotherm models of HAP-NH2 revealed that the uranium adsorption process was belonged to chemical adsorption. Furthermore, the main forces between uranium ions and HAP-NH2 were attributed to hydroxyl, amino and phosphorous functional groups.

Nitrogen and Phosphorous Co-Doped Carbon Felt for Enhancing VO2+/VO2 + Redox Reaction for Vanadium Redox Flow Battery

Nitrogen (N) and phosphorous (P) co-doped carbon felt is proposed as a promising electrode for enhancing VO2+/VO2 + redox reactions. Nitrogen and phosphorous can be simultaneously incorporated onto the carbon felt through straightforward synthesis method using aniline and triphenylphosphine as N and P source. The successful incorporation of nitrogen and phosphorous functional groups onto the carbon felt surface can be confirmed by X-ray photoelectron spectroscopy analysis. Compared to the carbon felt electrode doped solely with nitrogen or phosphorous functional groups on its surface, the electrochemical activity of the proposed carbon felt electrode towards slow redox reactions of VO2+/VO2 + can be greatly enhanced owing to the synergistic effects of the nitrogen and phosphorous functional groups. Consequently, VRFB cell assembled with N, P co-doped carbon felt electrode exhibits much stable cycle performance accompanied by highly improved energy efficiencies of 84.94 and 84.33% in the 1st and 50th cycle, respectively.

Facile low-temperature one-step synthesis of pomelo peel biochar under air atmosphere and its adsorption behaviors for Ag(I) and Pb(II)

This study prepared a novel low-cost surface functionalized carbon adsorbent (PPC) from biomass waste (pomelo peel) through a facile low-temperature (250 °C) one-step method under regular air atmosphere. The adsorption performance and mechanism of the carbon material for Ag(I) and Pb(II) were investigated by a range of sorption experiments and characterizations including SEM, EDX, XRD and FTIR. Sorption experimental results suggested that PPC had high adsorption capacities of 137.4 and 88.7 mg/g for Ag(I) and Pb(II), respectively, with adsorbent dosage of 2 g/L at unadjusted solution pH and room temperature (23 ± 1 °C). The characterization results indicated high-efficiency removal of the heavy metals by PPC was attributed to the strong chemical adsorption involving that Ag(I) ions were reduced as metallic Ag particles by oxygenic functional groups and Pb(II) ions were precipitated as Pb5(PO4)3OH crystals by phosphorous functional groups on the carbon surfaces. This study provides the possibility of synthesis high-efficient adsorbent using economic and environmental-friendly approach with low energy consumption.

Synthesis and capacitance performance of phosphorous-enriched carbon xerogel

Phosphorous-enriched nanoporous carbon materials gained much interest as electrodes used in the electrical double layer capacitors due to their large and prolonged electrochemical energy storage. In this work, two carbon xerogels (CX and CX-P) prepared from resorcinol–formaldehyde before and after chemical treatment with phosphoric acid were studied as electrode materials. Phosphoric acid treatment efficiently produced the phosphorous functional groups in the framework of carbon xerogel, enhancing the electrochemical capacitance. Samples were characterized by means of field emission scanning electron microscopy, nitrogen adsorption at −196 °C, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The electrochemical behaviors were demonstrated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. Although low significant changes in the morphology and porosity were made on CX-P xerogel, a remarkable abundant in the phosphorous-containing oxygen functional groups was developed with the chemical treatment. Efficiently produced phosphorous functional groups in the carbon xerogel framework enhanced the electrochemical capacitance to large extent. Capacitance value was increased 4.8 times from 38 F/g for CX electrode to 183 F/g for CX-P electrode at 5 mV/s. Moreover, CX-P preserved about 79% of capacitance on 200 mV/s scan rate. CX-P electrode exhibited identical triangular type charge-discharge curves throughout the increases in the current densities from 1 to 20 A/g, very promising for electrochemical capacitor applications.

Preparation of modified polyesters containing triphosphorous and their applications to PU flame-retardant coatings

Three phosphorous functional groups were introduced in one structural unit of polymer backbone to enhance the flame retardancy of PU coatings. In the first step, we synthesized tetramethylene bis(orthophosphate) (TBOP) that contained two phosphorus functional groups in one structural unit. In the next step, we synthesized modified polyesters (ATBTP-10,-20,-30) that contained triphosphorous groups by condensing polymerization of TBOP, 1,4-butanediol, trimethylolpropane, adipic acid, and phenylphosphonic acid (PPA). The amount of PPA in the ATBTPs was 10, 20, and 30 wt%. Then, flame-retardant PU coatings (AHFC−10,−20,−30) were prepared by curing ATBTPs with hexamethylene diisocyanate-biuret (curing agent) at room temperature. From the TGA analysis of diphosphorus-modified polyester (ATBT) and ATBTPs, the residues of ATBT, ATBTP-10, ATBTP-20, and ATBTP-30 were 24.6, 27.5, 29.2, and 31.9%, respectively. From this result, it was found that the residue increased in relation to the amount of PPA. Physical properties of the films of flame-retardant coatings were deteriorated with the addition of PPA (flame retarding component), however, all the films of flame-retardant coatings, except AHFC-30, met the required physical properties standard for coatings. Char lengths of the AHFCs measured by the 45° Meckel burner method were 2.9∼4.8 cm, and LOI values were 28∼31%, which indicates that the prepared AHFCs showed good flame retardancy.

Preparation and characterization of polyurethane flame‐retardant coatings using pyrophosphoric lactone‐modified polyesters/isophorone diisocyanate–isocyanurate

AbstractPyrophosphoric lactone‐modified polyester containing two phosphorous functional groups in one structural unit of base resin was synthesized to prepare a nontoxic, reactive flame‐retardant coatings. Then, the pyrophosphoric lactone‐modified polyester was cured at room temperature with isocyanate and isophorone diisocyanate (IPDI)–isocyanurate to get a two‐component polyurethane flame‐retardant coatings (TAPPU). Comparing the physical properties of the films of TAPPU with the film of nonflame‐retardant coatings, no deterioration of physical properties was observed with the incorporation of a flame‐retarding component into the resin. Three kinds of flame retarding tests were conducted, including the 45° Meckel burner method, limiting oxygen index method (LOI method), and oxygen combustion method with Cone calorimeter. It was observed that the char lengths were 3.1∼4.5 cm and LOI values were 27∼30%. These results indicate that the prepared coatings are good flame‐retardant ones. It was also found that the flame retardancy of those coatings was increased with the contents of phosphorous. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2316–2327, 2001

Metal-imprinted microsphere prepared by surface template polymerization and its application to chromatography

A metal ion-imprinted microsphere was prepared by surface molecular template polymerization. Trimethylolpropane trimethacrylate (TRIM), zinc ions, 1,12-dodecanediol-O, O′-diphenyl phosphonic acid (DDDPA) were used as a crosslinking agent, an imprint molecule, and a functional host molecule. The Zn(II)-imprinted microspheres, which are spherically well-defined particles, were prepared by using water-in-oil-in-water (W/O/W) multiple emulsions. The combination of TRIM and DDDPA serves to align the recognition sites resulting in better template sites produced on the polymer surface. We firstly conducted diagnostic zinc- and copper-ion adsorption tests with the Zn(II)-imprinted and unimprinted microspheres in order to make an assessment on the effectiveness of the molecular imprinting technique. Further, the metal-imprinted microspheres were applied to the column operation. The separation and recovery of metals were carried out by an adsorption column packed with the Zn(II)-imprinted microspheres. This performance was compared to that of commercial chelating resins that possess similar phosphoric functional groups. The Zn(II)-imprinted polymer shows an extremely high selectivity to the imprinted zinc ions compared to that of the commercial chelating resin. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 689–696, 2000