Concentrated Phosphoric Acid Research Articles

Leaching kinetics of waste pharmaceutical blister package aluminium in phosphoric acid media

This study investigated the process of treating secondary aluminium recovered from waste pharmaceutical blister packages (WPBs) using phosphoric acid solutions as a potential strategy for recycling this currently non-recycled waste material. The findings indicate that, when recycling via the hydrometallurgical process, the aluminium passivated during leaching can be effectively counteracted by employing moderately concentrated phosphoric acid solutions (1.0 M), elevated temperatures (60–80 °C) and specifically the addition of H2O2 (1.25–2.5 vol.%). Under these conditions, complete extraction of aluminium was achieved within four hours. The estimated activation energy (∼82 kJ/mol) indicates that the leaching reaction is primarily limited by the chemical reaction rate rather than film diffusion. An aluminium phosphate solution could be obtained by leaching WPBs in a way that is suitable for subsequent aluminium phosphate crystallisation. This approach could provide a promising pathway for valorising aluminium from the currently under-utilised waste fraction of pharmaceutical blister packages.

Coffea Rubiaceae Biochar for Removing Organic Dyes from Aqueous Media

High surface area materials with appropriate function groups used for removing pollutants from aqueous media [1-10]. Organic dyes are a toxic product of printing textiles, paper products, and manufacturing of plastics. In these processes the synthetic pigment can breach local waterways leading to decrease water transparency and consume oxygen which would lead to the destruction of aquatic life. The effects of cationic and anionic dyes such as Methylene Blue (MB) and Congo Red (CR) can result in the development of permanent gene mutations and cancer. As many techniques to treat the removal of organic dye contaminants from an aqueous medium are being developed, the most effective and cost-efficient method is absorption. Many adsorbents have been shown to be effective in absorbing organic molecules. Some adsorbents such as biochar can be cheaply and easily synthesized from waste materials or biomasses. It is estimated that approximately 18 tons of waste Coffea Rubiaceae grounds are generated every year and often end up in landfill. In this study, we aim to synthesize biochar from Coffea Rubiaceae ground. The synthesized Coffea Rubiaceae ground biochar is applied in removing organic dyes including CR and MB. The Coffea Rubiaceae ground was treated with concentrated phosphoric acid and then activated at high temperature. The obtained product was characterized by Powdered X-ray Diffraction (P-XRD) and Scanning Electron Microscopy-Energy Dispersive spectroscopy (SEM-EDS). The adsorption process will be examined under various temperature, pH, concentrations of biochar, and in the presence of interfering species. The concentration of dyes will be monitored by UV-spectrophotometer. In the study, the isotherm study showed that the biochar was capable of removing 98% of methylene blue and 73% of Congo Red. The preliminary result indicated the potential of Coffea Rubiaceae ground biochar in environmental remediation. References ME Mahmoud, TM Abdel-Fattah, MM Osman, SB Ahmed, Journal of Environmental Science and Health, Part A 47 (1), 130-141 (2012)TM Abdel-Fattah, B Bishop, Journal of Environmental Science and Health, Part A 39 (11-12), 2855-2866 (2004)ME Mahmoud, MM Osman, SB Ahmed, TM Abdel-Fattah, The Scientific World Journal 2012 (2012)TM Abdel-Fattah, ME Mahmoud, MM Osmam, SB Ahmed, Journal of Environmental Science and health, part A 49 (9), 1064-1076 (2014)Omar H. Elsayed-Ali, Hani E. Elsayed-Ali and Tarek M. Abdel-Fattah, Journal of Hazardous Materials, 185 (2-3), 1550-1557 (2011)Alya Elsayed-Ali, Tarek Abdel-Fattah, Hani Elsayled-Ali, Hani, Journal of Chemical Education, 88(8), 1126-1129 (2011).TM Abdel-Fattah, ME Mahmoud, Chemical engineering journal 172 (1), 177-183 (2011)ME Mahmoud, SS Haggag, TM Abdel-Fattah, Polyhedron 26 (14), 3956-3962 (2007)H Namkoong, E Biehler, G Namkoong, TM Abdel-Fattah, ACS omega 7 (44), 39931-39937 (2022)ME Mahmoud, AA Yakout, MT Abed El Aziz, MM Osman, TM Abdel-Fattah, Journal of Environmental Science and Health, Part A 50 (10), 1072-1081 (2015)

Facile preparation of near-monodisperse oligocellulose and its elastomeric derivatives with tunable mechanical properties

Oligocellulose (OC) with low polydispersity indices has been produced in large quantities using an improved method of acid-assisted hydrolysis, in which long cellulose chains disintegrate in concentrated phosphoric acid at moderately elevated temperatures. The hydrolysis time has been reduced by three orders of magnitude without compromising the overall yield of the process or the quality of OC products. The efficient production of high-quality OCs in large quantities allows for developing OC-derived elastomeric materials. A series of OC-graft-poly(isobornyl methacrylate-random-n-butyl acrylate) [OC-g-P(IBOMA-r-BA)] elastomers have been synthesized via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). OC-g-P(IBOMA-r-BA) elastomers have tunable molecular architectures and phase morphologies toward desirable mechanical properties and thermal stability suitable for various applications. The methodologies of the OC production and the graft-polymers synthesis in this study would help advance technologies for broader applications of bio-based elastomers.

Investigation of Ageing Methods on Gas Diffusion Layers for HT-PEMFC Application

Gas diffusion layers (GDLs) are commonly used materials for polymer electrolyte membrane fuel cell (PEMFC) applications. Key role of the GDL is the distribution of reaction gases evenly from the bipolar plate to the catalyst layer and enabling the removal of product water. Especially challenging are elevated temperatures and acidic conditions for materials applied in high temperature (HT) PEMFCs. In this work, ex-situ ageing tests on GDLs were performed. First, the GDLs were aged in an electrochemical set-up in concentrated phosphoric acid (PA) at temperatures up to 160 °C. After ageing, the GDLs were analysed regarding their morphology and changes in elemental composition. The results show lower impact after ageing at constant potentials of 0.1 V, 0.8 V and OCV but a significant effect of increasing temperature and higher potential of 1.2 V as well as potential cycling. This is confirmed by morphological analysis.

Validated ultraviolet high-performance liquid chromatography method for post-mortem 5-hydroxy-indoleacetic acid measurement in human cerebrospinal fluid

Objectives: The objective of this study was to develop an ultraviolet high-performance liquid chromatography (UV-HPLC) method for the measurement of 5-hydroxyindoleacetic acid (5-HIAA) in human cerebrospinal fluid (CSF) as a potential biomarker for neurological and psychiatric illnesses, including depressive disorders with suicidal behavior. Materials and Methods: The study utilized CSF samples from individuals brought for medicolegal autopsy. The 5-HIAA concentration was measured using a UV-HPLC method with three mobile-phase solvents. The most effective mobile phase solvent was then used to measure 5-HIAA in the CSF samples. The materials used in the study included CSF samples obtained from individuals brought for medico-legal autopsy, UV-HPLC equipment, and mobile phase solvents, including 5-hydroxyindole-3-acetic acid (Merck/sigma), acetonitrile, concentrated formic acid, concentrated acetic acid, methanol, and phosphoric acid. Statistical Analysis: This was done using R Studio (version 4.2.0). Results: The study found that the UV-HPLC method utilizing formic acid (0.05–0.1%): acetonitrile in a 1:9 as mobile phase was the most effective for measuring 5-HIAA in human CSF. The method exhibited excellent linearity, accuracy, and precision. Conclusion: The study concludes that the developed UV-HPLC method is reliable and effective for measuring 5-HIAA in human CSF. Measuring 5-HIAA levels in CSF can serve as a potential biomarker for neurological and psychiatric illnesses, including depressive disorders with suicidal behavior. This method is promising for clinical and forensic practice to diagnose suicidal cases. Further research is needed to determine the clinical significance of these findings and the potential for broader application in psychiatry. This article helps to give a practical, cost-effective methodology to detect CSF 5-HIAA.

Impact of the Catalyst Type and Dopant Composition on the Performance of High-Temperature PEM Fuel Cell

Increasing interest in hydrogen-powered fuel cells for electric energy generation led to the identification of serious limitations of state-of-the-art technologies. In particular, low-temperature fuel cell with a proton-exchange membrane (LT-PEM FC), which is widely considered as an optimal type for mobility, is reaching its technological limits. This is due to its operating temperature up to 90 °C, defined by properties of perfluorinated, sulfonated membranes used as PEM, requiring liquid water for ensuring their ionic conductivity. In the case of heavy duty applications, high-power LT-PEMFC stacks suffer from local overheating, which is currently solved by intensive cooling. Ineffective heat-exchange and necessity of water regime control lead to limitations in total energy utilization. Such problem can be solved by increasing operating temperature up to 180 °C, which is suitable for heat cogeneration. This requires application of appropriate PEM conducting even at an elevated temperature.Current state-of-the-art high-temperature PEM fuel cells (HT-PEM FCs) utilize PEMs based on polymer doped with phosphoric acid. Polymers, such as polybenzimidazole or pyridine aromatic polyether, act as a matrix and a bonding agent for the phosphoric acid dopant. Such PEMs can operate within the temperature range of 120 to 180 °C. In terms of the catalyst, HT-PEM FCs use Pt-based, nanoparticle catalysts on carbon support as in LT-PEM FCs. However, due to the mobile nature of phosphoric acid, which is responsible for pronounced catalyst degradation, poisoning as well as local catalytic layer flooding, Pt loading used in HT-PEM FCs is within an order of magnitude higher than in LT-PEM FCs.Due to its high operating temperature, HT-PEM FC technology offers numerous advantages, such as heat and electric energy cogeneration, simple water regime and, due to improved tolerance to catalyst poisons like CO, the possibility of utilization of contaminated H2 produced from fossil fuels and biomass. However, degradation of components, in particular the catalyst and the membrane, remain the main bottlenecks for wide HT-PEM FC commercialization. With respect to the latest advances in technology, two critical aspects were identified. Firstly, the necessity of new catalysts immobilized on durable supports, with improved stability, activity and resistance against poisoning by phosphate anions. Secondly, membrane with improved fixation of phosphoric acid and greater durability. A special case of the membrane degradation is the reduction of phosphoric acid, by hydrogen or at low potentials on the anode, to phosphorous acid. This compound can poison the anode catalyst, incorporate into the membrane as well as oxidize on the cathode to phosphoric acid, completing dopant lifecycle. Nevertheless, the exact impact of phosphorous acid on HT-PEM FC performance is still not fully understood.Accordingly, the study had two major goals. A first one was to investigate the performance and degradation of Pt-based alloy catalyst on graphene-type support using thin-film modified rotating disc electrode, half-cell and single cell setups. All experiments have been performed at HT-PEM FC relevant conditions, i.e. in concentrated phosphoric acid electrolyte within temperature range of 120 to 180 °C. On the other hand, the second one goal investigated the influence of the dopant composition in terms of phosphorous acid addition to phosphoric acid electrolyte on the activity of the catalyst.Performance of experimental catalysts based on Pt-Co on various supports, including carbon black and graphene was compared to commercial Pt/C catalyst. Experimental catalysts exhibited superior activity for oxygen reduction. The overall performance of single cells with experimental catalyst on the cathode was better than the one with the commercial catalyst, with best results obtained for the graphene supported Pt-Co. The impact of phosphorous acid on oxygen reduction on commercial Pt/C catalyst was significant, due to simultaneous oxidation of acid and reduction of oxygen, as confirmed using rotating disc electrode and half-cell setups. Using the addition of phosphorous acid after single cell break-in on the cathode, the anode or both electrodes at once, it was determined that after stabilization the performance improved. Electrochemical impedance spectroscopy showed that addition of phosphorous acid decreases cell Ohmic resistance, but the comparative I-U curves and CO stripping analysis performed on cathode indicated significant decrease of available Pt surface. This reflects the ambivalent influence of phosphorous acid on HT-PEM FC.This study was supported by the Grant Agency of the Czech Republic under project No. 22-23668K.

Nucleation & growth of α-Ti(HPO4)2·H2O single-crystal and its structure determination from X-ray single–crystal data

α-titanium phosphate phase [α-Ti(HPO4)2·H2O; abbreviated as α-TiP] is a nanolayered metal phosphate with several industrial and recent biotechnological applications related to their nanolayered morphology and ion exchange capabilities. Structural wise, α-TiP is a tetravalent metal phosphate that tends to crystallize into microcrystalline powder. Here we report that the crystallization of single α-TiP crystals with suitable dimensions (>50 μm) for single-crystal X-ray diffraction could be effectuated using a prolonged hydrothermal treatment of a metallic titanium alloy (Ti–6Al–4V) in a highly concentrated phosphoric acid aqueous solution. Accordingly, the single-crystal X-ray diffraction analysis revealed the crystalline structure in a monoclinic space group, P21/c, with a = 8.6288(5) Å, b = 5.00546(17) Å, c = 19.1468(11) Å, and β = 127.555(9)°. Although the space group is the same crystallographic space group that was previously reported from the microcrystalline powder relying on powder X-ray diffraction (PXRD) and neutron powder diffraction, the obtained unit cell volume is slightly larger. Bulk of the obtained crystals were also subjected to detailed analyses using polarization optical microscopy (POM), scanning electron microscopy combined with energy dispersive X-ray microanalysis (SEM-EDX), Fourier transform Infrared Spectroscopy (FTIR) and thermal analysis (TG/SDTA). The single crystals are hexagonally shaped and exhibit the exact titanium to phosphorus ratio expected for α-TiP. The bulk sample PXRD pattern resembles perfectly that reported for the α-TiP polycrystalline powder with clearly sharper peaks. TGA-SDTA analysis revealed the expected thermal behaviour for α-TiP phase and demonstrated their higher thermal stability when compared to the polycrystalline powder.

Quantitative analysis of the formation of monodisperse cello-oligomers obtained by phosphoric acid hydrolysis

Hydrolysis of cellulose in concentrated phosphoric acid is known to give two distinctive mono-disperse cello-oligomers: the degree of polymerization (DP) of 7 and 15. To understand the formation mechanism of monodisperse cello-oligomers, the transition of DP during phosphoric hydrolysis was monitored by size-exclusion chromatography combined with multiangle laser-light scattering analyses (SEC/MALLS). The obtained results suggested that not the hydrolysis at a specific length but random hydrolysis was likely. The rate of hydrolysis slowed down when the DP reached around 40, and the pool of cello-oligomers appeared at the incubation of 35 days. Then, the mono-disperse cello-oligomers were recovered from the pool of cello-oligomers by fractionation based on the solubility difference.

STUDY OF WAYS TO REDUCE THE VISCOSITY OF SUNFLOWER LECITHIN

Today, lecithin is the most important by-product of oilseed processing due to its numerous technological properties. Food industry technologists use lecithin as an emulsifier, wetting agent, stabilizer, viscosity regulator, crystal formation, etc. One of the main disadvantages of sunflower lecithin is the tendency to increase viscosity (plasticization) during storage. Such lecithin is difficult to use. Therefore, obtaining liquid lecithin with a viscosity of less than 12 Pa s (at 25 °C), which does not increase during its storage, is one of the urgent tasks of enterprises for the extraction and processing of vegetable fats. The article compares diluents of different types. Diluents of fatty nature - sunflower oil, oleic acid and its ethyl ester are characterized by a significantly lower viscosity compared to lecithin, therefore they can act as diluents that do not affect the quality of lecithin. However, their amounts are too large to achieve the goal of obtaining liquid lecithin. These amounts significantly reduce the "acetone insoluble" lecithin index. That is, oils, their acids and esters cannot be recommended for reducing the viscosity of lecithins in industry. It has been shown that the efficiency of divalent calcium salts as diluents is much greater, even at low concentrations of these substances. It has also been proven that the introduction of diluents must be carried out before the stage of drying the wet gum. To obtain liquid lecithin from plasticized lecithin, approximately twice as high concentrations of diluents are required compared to the preventive approach - the introduction of diluents into a wet gum. To obtain liquid sunflower lecithin from a wert gum to which diluents were added, the effective concentrations of diluents are as follows,%: sunflower oil - 13, oleic acid - 5, ethyl ester of oleic acid - 4, calcium chloride - 0.35, calcium acetate - 0.4, calcium orthophosphate - 0.4, concentrated phosphoric acid - 2. It is most expedient to use calcium salts in order to obtain high quality liquid lecithin.

The effect on the crystallization of calcium sulfate hemihydrate with the addition of magnesium in an MSMPR crystallizer

The effect of Mg2+ ions on the purity of calcium sulfate hemihydrate (HH) in concentrated phosphoric acid solution (wt% P2O5 39) was studied, using a continuously mixed suspension mixed product removal (MSMPR) crystallizer. Impurity distribution into crystals in the MSMPR crystallizer was considered by the population balance equation. The presence of Mg2+ ions make the crystals needle-like and agglomerated in large quantities, leading to more three-dimensional defects formation. This effect on crystals increases the uptake ratio (U) of phosphate and reduces HH purity and phosphorus yield. Through the scanning electron microscopy (SEM) and the focused beam reflectance measurement (FBRM), the effect of Mg2+ ions in inhibiting the radial growth of crystals and increasing the critical nuclear radius (rcrit) of crystals in solution was discovered. The influence of Mg2+ ions is crucial for the preparation of HH in the phosphoric acid hemihydrate process.

Effect of phosphoric acid treatment on the physical properties of zinc telluride thin films

Zinc Telluride (ZnTe) films were prepared by the closed space sublimation (CSS) method. The effect of chemical treatments with concentrated phosphoric acid, on the optical, electric and structural properties of the films was studied. Zinc-blend structure of the polycrystalline nature of the films was confirmed by x-ray diffraction (XRD) spectra. The energy dispersive x-ray (EDX) shows an increase in Te ratio on the surface of the film as exposed to phosphoric acid. In addition, the dc electrical resistivity of the films was dropped considerably. The refractive index, thickness, and thickness irregularity of the films were determined by fitting of the optical transmittance spectra in the wavelength range 400 to 2500 nm. The effect, of treatment, on the optical parameters is also reported.

Mikania micrantha extract/KI blend as a novel synergistic inhibitor for steel corrosion in concentrated H3PO4 solution

Mikania micrantha extract (MME) was prepared by reflux extraction from the exotic invasive weed of Mikania micrantha using ethanol water solution as the solvent. The synergistic inhibition effect and mechanism of MME and potassium iodide (KI) on the corrosion of cold rolled steel (CRS) in 4.0 M H3PO4 solution was investigated by gravimetric, electrochemical and surface analysis techniques for the first time. The results show that either MME or KI has moderate inhibitive action, and the maximum inhibition efficiency is below 65 % at 20 ℃. However, incorporation MME with KI can produce a synergism (s > 1), and obtain a pleasant inhibition of 92.9%. The adsorption of MME on CRS surface obeys Freundlich isotherm, while KI and MME/KI complex follow Langmuir isotherm. They are all mixed-type inhibitors, and MME/KI mixture significantly retards the electrochemical corrosion comparing with individual MME or KI. The process of electrochemical corrosion is controlled by charge transfer, and the charge transfer resistance follows the order of MME/KI > KI > MME. SEM and AFM demonstrate that the corrosion of CRS surface is efficiently retarded by the blend of MME and KI. From FTIR and XPS analysis, the formed layer of the synergistic inhibited CRS surface is mainly composed of the organic compounds with polar groups in MME. There is also a synergistic inhibition of the major components (rutin, quercetin, chlorogenic acid and ferulic acid) with KI. MME/KI can be deemed as a novel efficient inhibitor for steel in concentrated phosphoric acid, which develops an original path for the utilization of Mikania micrantha in the field of metallic corrosion and protection.

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“Stripy Zn array with preferential (002) crystal plane was fabricated through the facile treatment with concentrated phosphoric acid. The synergistic effect of stripy morphology and preferential crystal plane can increase the electroactive surface area, suppress the corrosion and hydrogen evolution of aqueous electrolyte, induce the horizontal growth along with basal (002) plane, and inhibit the formation of Zn dendrites.” image

Improving biogas production from different parts of spruce tree using leading pretreatments

Spruce is the most resistant type of lignocellulosic material to anaerobic digestion. Different parts of spruce tree, i.e., leaves, wood, branches, bark, fruit, and mixtures of these parts, were pretreated using the leading pretreatments, i.e., concentrated phosphoric acid, dilute sulfuric acid, and ethanolic organosolv pretreatment, to improve biogas production. The pretreatment effects on methane yield from both solid and liquid fractions of the pretreatments were evaluated. Different parts of the tree showed different behaviors. The maximum methane yields from the pretreated solids were obtained after phosphoric acid pretreatment, which yielded methane yields of 211.7 and 225.5 mL per g volatile solids (VS) of pretreated spruce leaves and mixture, respectively. The improvements were related to opened-up structure, crystallinity reduction, and delignification. Sulfuric acid pretreatment improved biomethane yield from liquids, but not solids. Moreover, organosolv pretreatment improved the yield from solids, but not wood, bark, and the mixture. The maximum methane production yield was 245.3 NmL CH4/gVS which was obtained from the organosolv liquor of spruce leaves. The highest overall methane production (252.9 L per Kg) was gained from the whole solid and liquid fractions from organosolv pretreatment of leaves. This methane yield corresponded to 2.4-fold improvement compared to that of the untreated leaves (107 NmL CH4/gVS). Thus, leaves and branches are less recalcitrant parts and do not need severe pretreatment, while bark and wood are the most recalcitrant parts and required severe pretreatment like concentrated phosphoric acid. Moreover, the mixture of all parts also required severe pretreatment for efficient biogas production.

Pretexturing and Anodization of W for Fabricating Ordered Anodic Porous WO3

Ordered anodic porous WO3 was prepared by the anodization of a W substrate with a depression pattern under a constant voltage of 18 V in concentrated phosphoric acid at 120 °C. However, the behavior of hole formation induced in depressions was found to be strongly affected by the depth and diameter of the depressions. Multiple holes were formed in a shallow depression during the initial stage of anodization, whereas only one hole was formed in a deep depression. In addition, when the depression diameter was small, the growth of fine holes around the induced holes was observed. Since the fine holes formed on the surface of anodic porous WO3 prevented the induced holes from growing in the depth direction, the formation of large-diameter depressions allowed the induced holes to grow deeper. The obtained ordered anodic porous WO3 can be used for various applications such as in photocatalysis and electrochromic devices.

One-pot hydrolytic hydrogenation of carbohydrates to hexitols catalyzed by Ru loaded P and Si-containing hierarchical porous biochars with excellent catalytic efficiency

The one-pot hydrolytic hydrogenation of carbohydrates to sugar alcohols is one of the important value-added transformations of biomass, but the hydrolysis efficiency of carbohydrates in this one-pot conversion is still limited by the high cleavage energy of their β-1,4-glycosidic bonds and the concomitant serious side-reactions. Therefore, it is necessary to develop the new acidic carriers to improve the key first-step hydrolysis. This paper discloses that a forestry processing waste bamboo powder can be converted into the P and Si-containing porous biochar (PSBC) via inserting silica sol, impregnating concentrated phosphoric acid (H3PO4) and heating carbonization. Due to the improved porosity and strong acidity of PSBC and its affinity to β-1,4-glycosidic bonds, this new acid carrier exhibits an outstanding catalysis performance for the hydrolysis of cellulose, cellobiose, especially sucrose and inulin, affording ca. 76.2% glucose yield in cellulose hydrolysis at 150 °C. More importantly, PSBC can efficiently and uniformly load Ru nanometer particles (average size of 1.5 nm) to fabricate 1%Ru/PSBC as an excellent bifunctional catalyst for the one-pot conversion of these carbohydrates to hexitols, affording ca. 85.2% hexitols with 51.7 h−1 turnover frequency in the one-pot conversion of cellulose under 150 °C and 3 MPa H2 pressure. This work not only provides an effective strategy for the preparation of biomass-derived bifunctional catalysts, but also it opens up new voyages for the development of efficient bio-refining.Graphical abstractRu-loaded P and Si-containing porous biochar (1% Ru/PSBC) is an excellent bifunctional catalyst for the hydrolytic hydrogenation of carbohydrates under relatively mild conditions, affording ca. 85.2% hexitols with 51.7 h−1 TOF in the one-pot conversion of cellulose.

The alleviation of lignin inhibition on enzymatic hydrolysis of cellulose by changing its ultrastructure

Lignin is regarded as the primary factor that inhibits enzymatic hydrolysis of cellulose. However, the impact of cellulose ultrastructure on the inhibition of lignin during enzymatic hydrolysis is still unclear. In this work, the addition of lignin during enzymatic hydrolysis of cellulose with different ultrastructure was investigated. Furthermore, the influences of changing cellulose ultrastructure on cellulose conversion of pine after hydrothermal treatment (HT) without and with additives (2-naphthol (2 N) and phloroglucinol (PL)) were explored in detail. The results showed that enzymatic hydrolyzability of allomorphic cellulose was strongly inhibited by lignin. In contrast, a small inhibition degree of lignin was observed for amorphous cellulose. Surprisingly, the cellulose conversion of HT treated pine was dramatically decreased (18.45–6.25%) after ball-milling treatment (BM), while it was significantly increased (18.45–74.49%) after concentrated phosphoric acid treatment (CP). In addition, the addition of 2 N or PL during HT could promote or inhibit cellulose conversion due to the changes in the condensation degree of lignin. These results indicated that the physiochemical structure of lignin has a significant effect on cellulose hydrolysis. More importantly, the increasing degree of cellulose conversion was enhanced in sequence from HT+PL (6.19–35.00%), HT (18.45–74.49%), to HT+ 2 N (21.12–92.30%) after CP, which was attributed to the reducing lignin condensation and changing cellulose ultrastructure. Overall, this work demonstrated that the inhibition degree of lignin was highly dependent on the cellulose ultrastructure.

Stripy zinc array with preferential crystal plane for the ultra‐long lifespan of zinc metal anodes for zinc ion batteries

AbstractRechargeable zinc (Zn) batteries have been regarded as a potential alternative for energy storage instrument, but the poor life‐span of Zn metal anodes restrain their commercial application. In this work, stripy Zn array (ZnSA) with preferential (002) crystal plane was designed and fabricated through the facile treatment with concentrated phosphoric acid. The depth of stripy array and the content of (002) plane were controlled through the optimization of etching time. The synergistic effect of stripy morphology and preferential crystal plane can increase the electroactive surface area, suppress the corrosion and hydrogen evolution of aqueous electrolyte, induce the horizontal growth along with basal (002) plane, and inhibit the formation of Zn dendrites. The as‐synthesized ZnSA electrodes can achieve ultra‐long lifespan of 2500 h at the current density of 2 mA cm−2 with a constant capacity of 2 mAh cm−2 and still maintain stable cycling of 1200 and 1400 h even at the higher current density of 10 mA cm−2 and plating/stripping depth of 5 mAh cm−2, respectively. This work proposes a facile and effective strategy to improve electrochemical performance of metallic Zn anodes and contributes to the commercial application of Zn ion batteries.image

Column dynamic studies for lanthanum(III) and neodymium(III) sorption from concentrated phosphoric acid by strongly acidic cation exchange resin (SQS-6)

ABSTRACT In this work, solid-liquid extraction of lanthanum and neodymium ions by column technique from concentrated phosphoric acid solutions using the strongly acidic cation exchange resin was experimentally investigated. Measurements of breakthrough curves were measured as a function of column bed depth, initial metal concentration in the feed solution and flow rate. It was found that the breakthrough and time increased with the increase in bed depth and the total mass adsorbed by La(III) and Nd(III) increased with increasing bed depth. At higher initial metal concentrations, the column is quickly saturated, resulting in shorter breakthrough and exhaustion time. It was observed that with increasing the initial metal concentration from 0.10 to 0.50 g/L, the equilibrium adsorption capacities increase from 9.68 to 27.45 mg/g for La(III) and from 4.57 to 19.43 mg/g for Nd(III). Breakthrough time reaching saturation was increased significantly with a decrease in the flow rate. As the flow rate increased from 1.0 to 4.0 ml/min, the exhaustion time of La(III) and Nd(III) decreased from 135.0 to 40.0 min and from 90.0 to 35.0 min, respectively. The capacity of La(III) and Nd(III) was found to be 33.55 and 17.30 mg/g, respectively. The experimental sorption capacity and the time required for 50% adsorbate breakthrough (τ) are close to those calculated resulting from the Thomas and Yoon-Nelson model. These results indicate that the experimental data obey the Thomas and Yoon-Nelson model.

Corrosion of austenitic stainless steels and nickel-based alloys in concentrated phosphoric acid at elevated temperatures

The corrosion sensitivity of several austenitic stainless steels (316L, 316Ti, Sanicro28, Sanicro35) and nickel-based alloys (Hastelloy G30 and Hastelloy G35) was determined at elevated temperatures in food grade phosphoric acid (FGPA). The materials were submerged in a harsh environment of >85 wt% FGPA at temperatures ranging from 80 to 160°C. The main aim was to understand the corrosion phenomena occurring in such environment and define the temperature range for which corrosion is within acceptable limits for these materials. Moreover, the role of a material's chemical composition on the corrosion resistance in phosphoric acid was experimentally elucidated. The corrosion sensitivity was determined by weight loss measurements, scanning electron microscopy and energy dispersive X-ray spectroscopy. The high concentrations of alloying elements in the selected metals allow them to form a protective passive surface film, which inhibits further oxidation. Depending on the stability of the passive film, materials will be corrosion resistant up to higher temperatures. Alloys with an increased molybdenum content showed a higher general and pitting corrosion resistance up to 140°C. Moreover, copper alloying resulted in an improved corrosion resistance at higher temperatures.