Diammonium Hydrogen Phosphate Solution Research Articles

Synthesis and characterization of hydroxyapatite nanoparticles from calcium hydroxide fouled with gases evolved from smokestack of glass industry

In glass industry, the evolved gases and fumes from burning the gas fuel absorbed in calcium hydroxide to minimize the pollution of environment. After a period of time, the calcium hydroxide fouled with sulphate and carbonate as action of the absorbed SO3 and CO2 gases. Based on our interest to treatment the solid waste materials, this study intended to convert the obtained waste of calcium hydroxide fouled with gases to valuable products. Firstly, this waste was treated with water, caustic soda and acids. The results confirmed the conversion of waste to pure calcium sulfate by treatment with 6 v/v% sulfuric acid. Secondly, the obtained calcium sulfate was reacted with ammonium dihydrogen phosphate solution for preparation of calcium hydroxyapatite (HAp) nanoparticles. The produced HAp sample was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and N2 adsorption measurements. The obtained findings confirmed that the HAp can be produced after calcination at 700 °C, nanorods-like of sizes ranged from 11 to 15 nm and with main surface functional groups of hydroxyapatite. TGA and DTA data indicated that HAp is thermally stable up to 700 °C. Also, the obtained HAp has Ca/P molar ratio of 1.60 and exhibited high total surface area of 146 m2/g with mesoporous structure which make this material can be used in medical and water purification applications.

Enhancing Thermal Insulation of Poly(β-Hydroxybutyrate) Composites with Charring-Foaming Agent-Coated Date Palm Wood

Date palm fiber (DPF) holds great potential for composite materials, but its flammability limits its practical applications. In this study, DPF was modified using a pad-drying method to impregnate it with a 5 wt.% solution of ammonium dihydrogen phosphate (ADP). These treated fibers were then utilized to fabricate poly(β-hydroxybutyrate)- (PHB-) based composites. The resulting thermal insulators were comprehensively evaluated for their flammability, physical, mechanical, and thermophysical properties, as well as morphological and thermal stability characteristics. The findings revealed a significant reduction in flame spread and smoke suppression; however, the concentration used is not sufficient to achieve the desired rating grades. The thermal insulation capacity of the modified fiber composites was substantially enhanced, particularly with the 40% PHB/DPF-ADP composite displaying the lowest thermal conductivity at 0.0564 W/m.K. Moreover, the presence of gaps and voids at the interface led to a reduction in tensile strength to 4-7 MPa. Additionally, the modified fiber composites exhibited significantly reduced water absorption (~0.76%), attributed to the formation of a highly water-resistant substance containing a furan compound. This work provides a simple and effective approach for achieving durable flame retardancy and long-term thermal insulation performance, offering promising opportunities for the practical application of biobased PHB composites.

Resistance of consolidated lime mortars to freeze–thaw and salt crystallization cycles by different accelerated durability tests

The present study aimed at evaluating the performance of untreated and consolidated lime mortars, in terms of durability and possible “delayed incompatibility” of the consolidants. Lime mortars samples were treated by an aqueous solution of diammonium hydrogen phosphate (DAP treatment) and a dispersion of nanolimes (NL treatment). The samples were then subjected to accelerated ageing by different methods: (1) freeze–thaw cycles; (2) salt crystallization cycles based on the European standard EN 12370 (often considered as highly aggressive); (3) salt crystallization cycles according to a new recommendation proposed by the RILEM TC 271-ASC (designed to provide less aggressive and more reliable ageing). The results of the study showed that the DAP-based treatment was able to significantly reduce damage caused by freeze–thaw cycles and salt weathering cycles by the RILEM procedure. In the case of salt weathering by the EN procedure, some risk of “delayed incompatibility” was highlighted for DAP, which can be considered an outcome of the combination between the salt weathering procedure itself and the consolidating treatment. For both freeze–thaw and salt weathering by either procedure, the residual mechanical properties of DAP samples at the end of the cycles were significantly higher than those of the untreated references and of the NL samples, for which the effects of the NL treatment were very modest.

Thermo-acoustic properties of monosaccharides D(−)-ribose and D(+)-xylose in aqueous diammonium hydrogen phosphate solutions at different temperatures

The volumetric and acoustic properties are used for investigating the interactions of polyhydroxy solutes D(−)-ribose and D(+)-xylose in different concentrations of diammonium hydrogen phosphate (DAP) solutions. Densities and speeds of sound of D(−)-ribose and D(+)-xylose in aqueous diammonium hydrogen phosphate (DAP) solutions have been measured over a temperature range of (298.15–318.15) K and at experimental pressure p = 0.1 MPa. Different parameters viz apparent molar volumes, Vϕ, partial molar volumes, apparent molar isentropic compression, partial molar isentropic compression, partial molar volume of transfer and molar isentropic compression of transfer are obtained using experimental density and ultrasonic speed data. The calculated parameters are discussed in rapports of solute–solvent interactions in solutions indicated the presence of ion-ion, ion-polar, hydrophilic-hydrophilic and hydrophobic–hydrophobic interactions in these ternary solutions, which was also confirmed from obtained positive values of apparent molar volume and negative values of apparent molar isentropic compressibility. Pair (VAB, KAB) and triplet (VABB, KABB) interaction coefficients determined by means of McMillan-Mayer theory are used to acquire valuable information about the dominance of pairwise interactions in the studied mixtures.

Life cycle assessment of stone consolidants for conservation of cultural heritage

The field of the conservation and repair of built cultural heritage shows a growing attention towards the environmental sustainability of materials and treatments used for conservation projects. As a standardized methodology that is widely adopted for the comparative evaluation of construction and building materials, life cycle assessment (LCA) can be usefully applied to conservation materials, if specific field-related issues on the definition of functional units and reference flows are properly addressed.In the present study, LCA is used to quantify the environmental footprint of four alternative consolidants for restoration of weathered carbonate substrates. An innovative treatment based on an aqueous solution of diammonium hydrogen phosphate (DAP) is compared against three commercial alternatives (lime nanoparticles, ethyl silicate, and acrylic resin). The issue of the definition of the reference flow (i.e., the amount of each consolidant required for the restoration of a given surface) is addressed through experimental tests on three model substrates (marble, limestone, and lime mortar), following two alternative criteria: i) application until apparent refusal, as recommended by product manufacturers, and ii) application to obtain a certain degree of consolidation, in terms of increase in compressive strength.The novel DAP consolidant is shown to have lower impacts than the alternatives on several environmental impact categories, mainly thanks to the absence of organic solvents in its formulation. The evaporation of volatiles after application (volatile organic compounds for the commercial consolidants, ammonia for the DAP consolidant) is highlighted as an environmental hotspot for all the consolidants.

In-situ micro-CT scanning and compressive strength assessment of diammonium hydrogen phosphate (DAP) treated chalk

The occurrence of wellbore mechanical failure is a consequence of the interaction among factors such as in situ stress, rock strength, and engineering procedures. The process of hydrocarbons production, causing reduction of pore pressure, alters the effective stresses in the vicinity of a borehole, leading to borehole instability issues. Estimating the rocks’ elastic modulus and compressive strength is essential to comprehend the rock matrix’s mechanical response during drilling and production operations. This study aimed to assess the practicality of Diammonium Hydrogen Phosphate (DAP) application as a chemical for strengthening chalk in hydrocarbon reservoirs, to make it resistant to high stresses and failure during drilling and production. The mechanical and physical properties of Austin chalk rock samples treated with DAP under mimicked reservoir conditions were studied. The results showed that DAP is a highly effective carbonate rock consolidating agent that improves the mechanical strength of the chalk. Compressive test measurements conducted on rocks treated at two different temperatures (ambient and 50 °C) showed that DAP effectively strengthened the rock matrix, resulting in an increase in its compressive strength (22–24%) and elastic modulus (up to 115%) compared to the untreated sample. The favorable outcomes of this research suggest that the DAP solution holds promise as a consolidation agent in hydrocarbon reservoirs. This contributes to the advancement of knowledge regarding effective strategies for mitigating mechanical failures of the wellbore during drilling and production.

Synthesis and Antimicrobial Analysis of High Surface Area Strontium-Substituted Calcium Phosphate Nanostructures for Bone Regeneration.

Continuous microwave-assisted flow synthesis has been used as a simple, more efficient, and low-cost route to fabricate a range of nanosized (<100 nm) strontium-substituted calcium phosphates. In this study, fine nanopowder was synthesized via a continuous flow synthesis with microwave assistance from the solutions of calcium nitrate tetrahydrate (with strontium nitrate as Sr2+ ion source) and diammonium hydrogen phosphate at pH 10 with a time duration of 5 min. The morphological characterization of the obtained powder has been carried out by employing techniques such as transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller surface area analysis. The chemical structural analysis to evaluate the surface properties was made by using X-ray photoelectron spectroscopy. Zeta potential analysis was performed to evaluate the colloidal stability of the particles. Antimicrobial studies were performed for all the compositions using four bacterial strains and an opportunistic human fungal pathogen Macrophomina phaseolina. It was found that the nanoproduct with high strontium content (15 wt% of strontium) showed pronounced antibacterial potential against M. luteus while it completely arrested the fungal growth after 48 h by all of its concentrations. Thus the synthesis strategy described herein facilitated the rapid production of nanosized Sr-substituted CaPs with excellent biological performance suitable for a bone replacement application.

A bio-inspired mineral precipitation method to improve the freeze-thaw resistance of cement concrete pavement

Mineral precipitation has been proven to be an effective surface treatment for reducing the porosity of Portland cement concrete (PCC), leading to significant improvement in its freeze-thaw (F-T) resistance. Inspired by human teeth, this study proposes to produce a protective surface layer for PCC through in-situ precipitating hydroxyapatite (HAP), the same mineral found in the tooth enamel, on the concrete surface to improve its freeze-thaw resistance. This protective layer was generated by simply treating the mortar surface with a diammonium hydrogen phosphate (DAP) solution. Experimental results reveal that the F-T resistance is significantly improved, with the DAP-treated specimens surviving three times as many cycles as the control group. The proposed treatment also enhances the compressive strength of the mortar specimens by 35% and reduces saturated water absorption by up to 50%. Analysis of mineralogy suggests that DAP reacts with calcium ions from hydrated cement, leading to HAP precipitation and calcium phosphate on the cement mortars' surface. Particularly, the nanoindentation results indicate that the mineral phase with a lower density tends to react more readily with DAP, leading to its conversion into minerals with significantly higher packing density. Quantitative backscattered scanning electrons (BSE) images and mercury intrusion porosimetry (MIP) analysis verify that the microstructure of the cement mortar surface was densified by the formation of HAP and calcium phosphate induced by the proposed treatment. The proposed method exhibits great potential in enhancing the longevity of PCC pavements in cold regions.

4D imaging and quantification of the effect of a Phosphate-Based treatment on building materials by means of synchrotron X-ray Microtomography: New insights into the dynamic of the consolidation process

Diammonium hydrogen phosphate (DAP) solutions are used as consolidants for carbonate stone materials through the crystallization whithin the original matrix of newly formed crystalline phases. However, the formation mechanism of the new phases within the stone microstructure, and their effects on the porous system, strongly depend on the DAP molarity, the treatment method, and the stone microstructure. In this study, we obtained real-time quantitative information on the structural evolutions induced by the treatment process on the Noto limestone, a porous carbonate stone used as a building stone since antiquity, by synchrotron X-ray Microtomography. With the aid of 4D image analysis, microstructural modifications in terms of porosity, interconnection, and pore size distribution have been demonstrated in different stadia of the consolidation process, and the influence of molarity was asserted. This study paves the way for a deeper understanding of consolidation mechanisms and the effects induced overtime on the 3D microstructural features of porous materials by inorganic treatment.

Enhancing Fracture Conductivity in Soft Chalk Formations With Diammonium Phosphate Treatment: A Study at High Temperature, Pressure, and Stresses

Summary This study aims to address the problem of fracture hydraulic conductivity decline in soft formations using a diammonium hydrogen phosphate (DAP) solution. A naturally weak carbonate, Austin chalk was chosen as an ideal specimen. Flat chalk samples with reduced elastic modulus and roughness were evaluated before and after aging with 1 M DAP for 72 hours at 75°C and 1,000 psi. The fracture gas conductivity of DAP-aged and untreated samples was measured at various flow rates and stresses while recording sample compaction using linear variable differential transformers (LVDTs). The study found that DAP aging increased the reduced elastic modulus of chalk specimens up to 330% of the original value, improving their resistance to deformation and failure under stress by 200 psi. The hydraulic conductivity of DAP-aged samples was at least twice that of untreated samples, with an extended hydraulic fracture conductivity seven times higher than that of the untreated ones. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis revealed that DAP reacted with the chalk to form hydroxyapatite (HAP), which binds the calcite grains, yielding a stiffer, more deformation-resisting rock surface. Overall, the study demonstrates the potential of chemically enhancing and extending the fracture hydraulic conductivity of weak carbonates using DAP.

New insights on conservation of marble artworks from computational chemistry

Architectural elements made of marble are subject to deterioration when exposed outdoors. A promising route to prevent deterioration is treating marble with an aqueous solution of diammonium hydrogen phosphate (DAP) to form hydroxyapatite (HAP). In this way, dissolution of marble can be prevented (as the solubility of HAP is orders of magnitude lower than calcite’s solubility) and cracks can be sealed (as HAP creates new bridges between calcite grains). To improve the treatment performance, the addition of alcohol to the DAP solution has recently been investigated with encouraging results. Here, we combined computational chemistry and experimental tests to identify alternative organic solvents that can further increase the treatment efficacy. First, we used density functional theory and molecular dynamics to screen alternative solvents (water, ethanol, isopropanol, and acetone), comparing their binding affinity and competitive adsorption behaviour onto calcite. Then, we treated marble specimens with DAP solutions with the additives and characterized the resulting performance. The results of the study indicate that acetone binds to calcite less strongly than the other solvents and does not completely displace water from the surface, which is expected to be beneficial. Nonetheless, the coating formed using acetone showed similar composition, thickness, and protective ability as the coatings formed with the other solvents. In terms of consolidation, all solvents were effective in improving surface and bulk mechanical properties. Overall, the extent of interaction with the calcite surface does not seem to be a critical factor. This can be explained by considering that, in addition to the different binding affinity to the calcite surface, the solvents may weaken the hydration shell of the phosphate ions in the DAP solution, thus facilitating the formation of HAP. Based on our results, this latter aspect seems to be predominant. Additional computational studies are in progress to elucidate this aspect.

Hydroxyapatite stabilized silver nanoparticles and their catalytic activity

Abstract In the current work, hydroxyapatite (HAP) particles were synthesized by using Citrus Limon. Pectin was extracted from lemon and was used as stabilizing agent during particles synthesis. HAP particles were synthesized by mixing calcium chloride solution and ammonium dihydrogen phosphate solution and pectin in a definite ratio. Fabrication of silver nanoparticles was carried out in the presence of HAP particles to obtain Ag-HAP hybrid particles. HAP and Ag-HAP systems were characterized using Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopy (EDX). The catalytic activity of Ag-HAP system was evaluated by reducing 4-nitrophenol and by degrading organic dyes (Rhodamine b, Brilliant blue and Methyl orange). The experimental results showed that Ag-HAP hybrid particles have good catalytic activity and may be used for catalysis of different organic reactions.

Effect of solvents and pH on in situ formation of hydroxyapatite for stone conservation

In situ formation of hydroxyapatite (HAP) inside the cracks and on the surface of calcareous substrates (e.g. marble and limestone) has been proposed for consolidation and protection of cultural heritage. HAP can be formed in situ by reacting the substrate with an aqueous solution of diammonium hydrogen phosphate (DAP). Taking inspiration from literature on bioceramics and from recent computational results, in the present study different strategies were explored to improve the consolidating efficacy of the DAP solution, namely by increasing pH or by adding organic solvents. A 1 M DAP +1 mM CaCl2 solution was taken as a reference and compared to 10-fold more diluted solutions (0.1 M DAP + 0.1 mM CaCl2) at pH 8, 10 or 12 and with addition of 20 wt% ethanol, isopropanol, or acetone. The solutions were applied onto weathered marble specimens and the formation of the new phases was characterized by FEG-SEM and XRD, while the strengthening ability was assessed in terms of bulk mechanical properties and surface properties. The results of this study indicate that apatite phases (mostly likely carbonate HAP with possible stoichiometric HAP) were formed as the result of all treatments, except at pH 12 when undesired ammonium calcium phosphate hydrate was formed. In terms of strengthening efficacy, when in-depth consolidation is needed, the more concentrated DAP solutions are able to provide higher strengthening ability. When consolidation of the most superficial layer is desired, less concentrated solutions are able to provide satisfactory results, allowing for a substantial reduction in the use of DAP with economic and environmental advantages.

Conductivity Enhancement of Fractured Carbonates through High-Temperature Diammonium Hydrogen Phosphate Consolidation: A Preliminary Study

SummaryIn well stimulation operations, the ability to sustain long-term conductivity of hydraulic/acid fractures defines an efficient and effective hydrocarbon production operation. However, it is challenging to keep the fracture conductive in the soft and weak carbonate formations due to many challenges. For example, the plastic deformation of rocks causes proppant embedment or asperities failure, resulting in fracture conductivity reduction. Consolidating chemicals, particularly diammonium hydrogen phosphate (DAP), have shown to be effective in rock consolidation and could reduce the decline in fracture conductivity if applied to carbonate formations. The previous research tested DAP at ambient conditions, whereas this work involves studying the hardening properties of DAP at reservoir conditions. The solutions with two initial concentrations (1 and 0.8 M) were tested at 77°F (ambient), 122°F, and 176°F. Furthermore, a post-treatment analysis was conducted to compare the performance of the chemical under different conditions. The analysis included understanding the changes in carbonate rocks’ (limestone and chalk) hardness (impulse hammer test and indentation test), porosity (helium porosimeter), permeability (steady-state and unsteady state nitrogen injection), and mineralogy [X-ray diffraction (XRD) and scanning electron microscopy (SEM)]. Results demonstrated that both rock lithologies reacted efficiently with the DAP solution, presented in terms of the noticeable improvements in their hardness. The elevated temperatures positively affected rock hardness, leading to a more than 100% increase in hardness for most samples. After obtaining successful results from experiments at various temperatures, the pilot American Petroleum Institute (API) conductivity experiments were conducted, testing the conductivity sustenance through the rock hardening concept. Preliminary API conductivity experiments have demonstrated that treated rock samples with DAP provided higher conductivity values than the untreated samples at high stresses. The results shown in this study provide a good foundation for further studies on the implementation of DAP in actual acid/hydraulic fracturing field operations.

The implications of pulsating anode potential on the electrochemical recovery of phosphate as magnesium ammonium phosphate hexahydrate (struvite)

A sustainable approach to address the limited availability of rock phosphate is to electrochemically recover phosphorus (P) as struvite (magnesium ammonium phosphate hexahydrate, MgNH4PO4·6H2O) fertilizer. On Mg surfaces, however, magnesium hydroxide (Mg(OH)2) and/or struvite form resistive films that limit the release of divalent Mg ions and reduce struvite precipitation. The present work enhances struvite recovery through the application of a dynamic voltage with a sinusoidal waveform. Compared to a constant potential, our results demonstrated that a dynamic potential could enhance the rupture of the passivating film, and facilitate the release of Mg2+ from the metal anode, thereby overcoming passivation problems. Ammonium dihydrogen phosphate (NH4H2PO4, 10 mM) solutions at neutral pH were used as test solutions. A 160–192 % increase in magnesium release was observed versus constant voltage applications, resulting in a 1.3x increase in phosphate recovery. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterizations indicated that the precipitate recovered contained struvite. An analysis of electrode surfaces using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) confirms a greater extent of passivating film breakdown under dynamic voltages.

Analyze and Compare the Crystallographic Changes for Zinc Substituted Hydroxyapatite using X-Ray Diffraction

The main motive of the study is to analyze and compare the crystallographic changes using the X-Ray diffraction method for zinc substituted hydroxyapatite. Materials and Methods: Different types of zinc substituted hydroxyapatite are used. Calcium nitrate tetrahydrate, zinc chloride hexahydrate, diammonium hydrogen phosphate and ammonium hydroxide solutions are added and they are mixed with ammonium hydroxide solution. The ultrasonic was used to carry the precipitation method. The zinc substituted data(N=4), the total sample size was calculated as 4 using clinclac.com, alpha error is 0.05, the G power at 80%, the enrollment ratio to 0:1 and the confidence interval to 95% and the total sample size was computed. Result: Using SPSS software and a one sample T-test, 0% 1%, 5% and 10% percent of zinc with hydroxyapatite were calculated. There is a statistical significance, P=0.002, (p&lt;0.05). The wt% of Zinc hydroxyapatite is of no significance with P=0.177, (p&lt;0.05). The result shows that when compared to other percentages, 10% of zinc substituted hydroxyapatite. Conclusion: The analysis of this study shows that Hydroxyapatite with 10% Zinc Doped Hydroxyapatite has Superior qualities to other Substitutes for future medical applications.

Application of Pulsed Potential Waveform in Electrochemical Phosphate Recovery As Struvite from Wastewater

Phosphate production is apprehended to peak as early as 2030, and post-peak, phosphate production, and thus food supply, will be limited by dwindling resources, strained economics, and reduced rock quality, with remaining resources expected to last 50-300 years. The limited supply of phosphate demands P conservation by changing the food production system, from fertilization to wastewater treatment. Stuvite (MgNH4PO4.6H2O) has been recognized as a high-value, slow-release, effective fertilizer that can be obtained from both solid (e.g., food, animal, and human waste) and liquid wastes (e.g., wastewater from industrial, municipal, and agricultural operations). The goal of our research is to recover struvite from wastewater using an alkaline electrochemical reactor with a magnesium alloy anode and a cathode constructed of standard catalysts for reducing water to hydrogen gas and hydroxide. Over time with successive reactor batches, the magnesium electrode used to generate magnesium cations in solution and precipitate struvite becomes severely fouled, which in turn increases energy demand and decrease struvite fertilizer recovery. A dynamic, pulsed voltage waveform, as opposed to a constant voltage, causes a stress-strain-like effect at the magnesium electrode surface, thereby preventing or reducing the amount of struvite precipitate that would attach to the electrode. In an aqueous solution of ammonium dihydrogen phosphate (NH4H2PO4, 10 mM) at neutral pH, a significant 50% increase in magnesium release is observed compared to constant voltage applications, resulting in a 30% increase in phosphate recovery. Studies of the recovered precipitate using X-ray diffraction and scanning electron microscopy (SEM) indicate the presence of struvite.

Conservation of Archaeological Bones: Assessment of Innovative Phosphate Consolidants in Comparison with Paraloid B72.

Aqueous solutions of diammonium hydrogen phosphate (DAP) have been recently proposed for consolidation of archeological bones, as an alternative to traditional products. Here, we investigated several routes to improve the performance of the DAP-based treatment, namely increasing the DAP concentration, adding calcium ions and adding ethanol to the DAP solution. Archaeological bones dated to about 1–0.8 million years ago were used for the tests. After preliminary screening by FTIR microscopy and FEG-SEM among different formulations, confirming the formation of new hydroxyapatite phases, the most promising formulation was selected, namely a 3 M DAP solution. The strengthening ability of this formulation was systematically compared to that of the most widely used commercial consolidant, namely Paraloid B72. The performance of the two treatments was evaluated in terms of Knoop and Vickers microhardness, resistance to scratch and resistance to material loss by peeling off. The results of the study show that the DAP treatment was able to improve the bone surface properties and also the resistance to material loss by peeling off, which is more dependent on in-depth consolidation. Paraloid B72 led to the formation of a layer of acrylic resin on the bone surface, which influenced the mechanical tests. Nonetheless, Paraloid B72 was able to penetrate in depth and substantially decrease the material loss by peeling off, even more effectively than DAP. The results of this study indicate that the potential of the DAP treatment for bone consolidation is confirmed.

Development of Fire Retardant on Jute by Chemical Means

Jute is highly flammable in character. Due to its high degree of flammability, the versatile use of this fibre is handicapped to some extent, particularly in some specific purpose where jute products with flame resistance finishes and demanded. Considering this disadvantage, a research project was undertaken to make this fibre flameproof and therefore safer in specialized textile uses. The study was performed using yarn and fabrics which were desized with diastase and lissapol-N. Yarn and fabrics were scoured with sodium carbonate, sodium hydroxide under some standard conditions. These pretreated yarns and fabrics were used in the whole experimental work. The treated yarns were tested for flame retardant by subjecting them to the luminous flame of Bunsen burner and by observing the time of flaming (after flame) and time of glowing (flameless combustion, after glow), if any Percentage losses of strength of the treated yarn and fabrics were also measured by standard method. Different solutions of fire resistant chemicals were prepared to change the chemical, concentration and pH ratio of the solution. Jute fabrics and yarns treated with 65% solution of urea and ammonium dihydrogen phosphate (the ratio of urea and ADP being 3:2) together with 2% Turpex NP and 3-6% perapret PE-40% were found durably flame retardant causing minimum loss of the strength. This research was focused on fire resistant treatment of jute yarn and fabrics with different chemicals to make jute products for diversified textile uses.

(Digital Presentation) Magnesium Shot Filled Electrochemical Packed Bed Reactor for Phosphate Recovery

The global food-energy-water nexus encompasses energy efficient recovery and reuse of nutrients. However, limited phosphate sources and pollution from phosphate-rich fertilizers adversely affect global food security, which mandates energy-efficient technologies, like electrochemical struvite (MgNH4PO4.6H2O) production, with nutrient capture and reuse potential. In this study, we report a first-of-its-kind electrochemical struvite precipitation in an electrochemical packed bed reactor filled with pure Mg shots, which achieved shortened retention time and higher phosphate removal efficiency, compared to the previous batch electrochemical system used by our group. Mg loading, equivalent to the weight of the immersed Mg anode in the batch reactor, was fixed in the packed bed reactor at the beginning of each experiment. The feed flow rate (0.5-5 LPM) and Mg shot diameter (0.5-1.5 cm) were varied to study the performance of electrochemical precipitation column in a 10 mM synthetic solution of ammonium dihydrogen phosphate (NH4H2PO4, 10 mM) at neutral pH. The continuous flow system achieved a >40% phosphate removal over 4 h. The experimental results help in understanding the different parameters that affect struvite recovery from a flow-based reactor design, as well as an understanding of the challenges involved in transitioning from a batch reactor to a flow reactor.