Mass Ratio Of Agent Research Articles

OPTIMIZATION OF PECTIN EXTRACTION FROM SUGAR BEET PULP USING MICROWAVE TREATMENT

Pectin is a natural heteropolysaccharide contained in plant cell walls and plant waste. In recent years, various alternative methods (enzymatic, microwave, ultrasonic) have been used to increase the yield of pectin, which can increase the efficiency of the process, pectin yield and improve quality. The principal advantages of using microwaves for the extraction of pectin from plant waste materials are the significant reduction in processing time, the higher yield of the natural polymer and the quality maintenance due to the more gentle processing conditions. The purpose of the work is to improve the method of pectin extraction from beet pulp using microwave treatment. Experiments were carried out to establish the optimal conditions of polysaccharide extraction. The pectin extraction was optimized by varying the microwave power, the pH of the medium, the processing time, the type of extracting agent (citric, malic, hydrochloric and acetic acids) and the ratio of beet pulp to extracting agent. A titrimetric method was used to determine the degree of esterification and the uronide component. Results and discussion. Extraction of pectin from sugar beet pulp includes the following main steps: polymer extraction by microwave treatment, pectin purification and drying. Among the studied parameters, the ratio of beet pulp to extracting agent and microwave processing time had a significant effect on the yield and properties of pectin. The highest yield of pectin (5.7%) was achieved at a heating power of 520 W, pH - 2.0, processing time of 30 minutes, using citric acid as the extraction agent and a beet pulp to extraction agent mass ratio of 15:1. IR spectra of the extracted pectin show the presence of characteristic bands typical of the pectin spectrum. Conclusions. Varying the parameters of pectin extraction from sugar beet pulp using microwave treatment allowed to increase the yield of pectin with desired characteristics. The perspective of using ecologically pure organic acids (citric and malic acids) as an extracting agent is shown.

Structure, Property Optimization, and Adsorption Properties of N,N'-methylenebisacrylamide Cross-Linked Polyacrylic Acid Hydrogels under Different Curing Conditions.

In this study, polyacrylic acid hydrogels were prepared by modulating the cross-linking agent mass ratio using UV and heat curing methods. The structures and properties of the hydrogels were characterized and analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results showed that the mechanical properties of the hydrogels prepared through UV curing were better than those prepared through heat curing. The maximum mechanical tensile strength of 139 kPa was achieved at a cross-linking agent mass ratio of 3.85% with 20 min of UV curing, and the maximum mechanical compressive strength of 0.16 MPa was achieved at a cross-linking agent mass ratio of 2.91% with 20 min of UV curing. However, the hydrogels prepared by heat curing had a higher tensile strength than those prepared using the heat curing method. In addition, the thermally cured hydrogels had higher water absorption and adsorption properties. Moreover, the PAA hydrogels prepared at cross-linking agent mass ratios of 1.91 and 2.91% with 2 h of the heat curing method had the best swelling properties. Moreover, the increase in the cross-linker mass concentration led to a decrease in the pore size and porosity and to a more compact structure.

Highly sensitive formaldehyde detection using biomass hydrogel with core-shell structure

The indoor formaldehyde concentration is in trace quantities; however, it considerably deteriorates indoor air quality and poses a serious threat to human health and ecosystems. Since current formaldehyde analyzers are only suitable for high-concentration detection or are expensive, there is a pressing need for an easy-to-use, storable, and highly sensitive formaldehyde detector. In this study, we developed a colorimetric sensing sphere using affordable and eco-friendly sodium alginate as a porous matrix. Polyethyleneimine, a molecule rich in amino groups, and an indicator are embedded in the matrix to create a core-shell structured, responsive porous hydrogel colorimetric sensor for indoor formaldehyde detection. The sensing sphere exhibits high sensitivity and excellent detection limits at a polyethyleneimine to pH agent mass ratio of 23:1, reaching a sensitivity of 0.02 mg/m3 and a detection limit of 0.06 mg/m3. The sensing sphere demonstrates superior selectivity among common indoor pollutants and remains unaffected by temperature (up to 70 ℃) or humidity (20–80 %) changes. Moreover, the core-shell structure of the colorimetric sensor ball addresses the poor stability and storage issues. The core-shell structure resists interference from external environmental changes, offering remarkable stability for 6 months and longer, hence, facilitating easy transportation and storage. The colorimetric sensing sphere is simple, cost-effective, and reliable for ordinary households, thus maintaining the indoor air quality and health of residents.

Research on Fe Removal, Regeneration Process, and Mechanical Properties of Mg Alloy AM50A

In recent years, the widespread application of Mg alloy casting and Mg alloy products has generated a large amount of Mg alloy waste. This experiment used a single factor experimental analysis method to study the optimal process for removing Fe from Mg alloy AM50A waste, and developed an efficient Fe removal and regeneration process for Mg alloy AM50A. It was found that the optimal refining temperature for removing Fe ions was 670 °C, the optimal refining (RJ-2) agent mass ratio was 1.5%, and the optimal refining time was 40 min. Regenerated J40-1.5-AM50A Mg alloy was prepared using the best refining process, and its composition and mechanical properties were tested and analyzed. The experimental results show that the composition of the regenerated J40-1.5-AM50A Mg alloy prepared by this method is consistent with AM50A, with an Fe removal rate of 96.2%. The mechanical properties were improved compared to the original AM50A sample, with a maximum tensile strength increase of 1.611 KN and a tensile strength increase of 26.333 MPa. The elongation after fracture is 2.25 times that of the original sample. Research has shown that the RJ-2 refining agent can provide mechanical properties of magnesium alloys during the refining process. By analyzing the composition, XRD, SEM, and EDS of AM50A (Fe) and J40-1.5-AM50A, it was found that the refining process accelerates the removal of Fe in the form of Fe deposition.

Citric Acid Leaching of Industrial BOF Slags

About 800,000 t of BOF slag are generated per year during the steel production process by Austrian steel plants of voestalpine. Austrian legislative authorities restrict the use as recycling construction material in road building to the bituminous binder course, which additionally includes a lifetime responsibility of the producer for possible future contaminants that currently have not been considered.Alternative routines of recycling of BOF slag are thus addressed in a project of K1-MET within the COMET funding program of the Austrian Research Promotion Agency (FFG), financed by the Austrian government and industry. Selective leaching processes are investigated by the Chair of Mineral Processing, Montanuniversität Leoben to recover the iron bearing oxides contained in the slag (i.e. magnesio wuestite, Ca- and Mg ferrites) with the lowest amount of phosphorous possible, which is contained in larnite (dicalciumsilicate) only.Common mineral processing methods obtained only poor results due to intergrowth conditions. Selective leaching of P containing larnite by citric acid may provide an alternative.Systematic tests for optimum leaching conditions concerning optimum mass ratio of agent to industrial slag, volume of eluate, leaching time, leaching temperature, and pH were performed. As the acid consumption is comparatively high, a special effort was spent on the regeneration of citric acid.

Study on pulverized coal gasification using waste heat from high temperature blast furnace slag particles

A combined species transport and reaction-discrete phase model was established to numerically study pulverized coal gasification using waste heat from high temperature slag particles. The effects of slag particles temperature, coal/gasification agent mass ratio and water content in gasification agent on the gasification characteristics were discussed. The results indicate that higher particle temperature leads to better gasification reaction efficiency. Compared to the maximum syngas productivity (67.9%) and carbon conversion efficiency (91.7%) at 1500 K, they are respectively reduced to about 45% and 60% when temperature drops to 1000 K. Excessive or insufficient pulverized coal would have a negative effect on the syngas production for a specific flow rate of gasification agent, and the appropriate proportion range is 0.8–0.84. The CO yield declines with the increase of particles diameter, while H2 firstly increases and then declines attributing to the lower gasification agent temperature and higher flow velocity gained at larger diameter. The raise of water content in gasification agent is beneficial to H2 production, but CO yield continues to decline after the water content exceeds 5% for the reason that the incomplete combustion of volatiles and the gasification reaction of coke are inhibited. The diameter of slag particles and the water content suitable for coal gasification reaction are 2.0–2.5 mm and 5%–10%, respectively.

A novel approach to extract Nb, Y and Ce from a niobium-bearing ore of low grade by roasting KHSO4–H2SO4 system

In this work, a novel approach of leaching valuable metals, such as niobium, yttrium and cerium, from a niobium-bearing ore of low grade by roasting KHSO4–H2SO4 system was experimentally studied. Through the work, the effects of roasting temperature, roasting time, mass ratio of agents to ore and the types of leaching agents on the extraction of Nb, Y and Ce were investigated, and the roasting KHSO4–H2SO4–ore system was thought as an effective method to extract these valuable metals. It was found that the recovery of Nb, Y and Ce can, respectively, reach 90.20%, 97.22% and 98.41% in condition of roasting temperature of 300 °C, roasting time of 2 h, mass ratio of KHSO4-to-H2SO4 to ore of 0.5:1:1, particle size of − 74 μm (~ 95%), leaching solution of oxalic acid (30 g·L−1), leaching temperature of 90 °C and leaching liquid-to-solid ratio of 5:1. The leaching kinetics of the calcined Nb-bearing ore in oxalic acid solution was successfully modeled by chemical reaction model, and the apparent activity energy was obtained to be 14.16 kJ·mol−1. The results generated from this work will provide the fundamentals for extracting Nb, Y and Ce from a niobium-bearing ore of low grade and have potential applications value in future.

Design and evaluation of microencapsulated systems containing extract of whole green coffee fruit rich in phenolic acids

The optimal conditions to microencapsulate green coffee (Coffea canephora) fruit extract (GCFE) by spray drying using a maltodextrin (MD)-gum Arabic (GA) mixture as carrier material were selected. For this purpose, a Central Composite Rotational Design was applied to investigate the combined effects of the MD percentage in the mixture and the extract-to-carrier agent mass ratio (mE/mC) as the independent variables. These effects were modelled by second-order polynomial models on several responses, namely process yield, encapsulation efficiency, water activity, losses of reducing capacity, caffeic acid, caffeine, trigonelline, 5-O-caffeoilquinic acid (5-CQA) from microcapsules (MCs) and 5-CQA retention after 180-days storage. The statistically significant effects were then submitted to more in-depth analysis by Response Surface Methodology. The highest process yield was obtained using a MD percentage of 80% and a mE/mC ratio of 1:1.5 (w/w). Both microencapsulated and non-encapsulated GCFE showed good stability during the accelerated stability study performed at 40 °C for 180 days. Surface morphology and particle size distribution of GCFE-loaded MCs were shown to be suitable for use in the food industry.

Production and characterization of activated carbons from Rhododendron ponticum L. by physical and chemical activation

In this study, the production of activated carbon by physical and chemical activation methods from Rhododendron ponticum L. was studied. In the physical activation method, Rhododendron ponticum L. was directly heated in nitrogen atmosphere at temperatures of 450, 550, and 650 °C and subjected to CO2 atmosphere for 1 h. Chars produced from Rhododendron ponticum L. were used in the chemical activation method. The chars were obtained by heating to 450 °C at a nitrogen atmosphere and waiting at this temperature for 2 h. H3PO4, KOH, and K2CO3 were used as chemical agents, and the char and chemical agent mass ratio were ½, and the chars were carbonized to a temperature of 550 °C at a nitrogen atmosphere and allowed to stand at this temperature for 1 h. The structural characterization of the activated carbons produced by both methods was carried out using nitrogen adsorption at − 196 °C and scanning electron microscope.

Intumescent flame-retardant poly(1, 4-butylene terephthalate) with ammonium polyphosphate and a hyperbranched triazine charring-foaming agent: Flame retardancy performance and mechanisms

Intumescent flame-retardant poly(1, 4-butylene terephthalate) composites with ammonium polyphosphate and a hyperbranched triazine charring-foaming agent were prepared through melt blending. The flame retardancy, pyrolysis behavior, and flame-retardant mechanism of flame-retardant poly(1, 4-butylene terephthalate) were investigated using flammability tests, cone calorimeter measurements, thermogravimetric analysis including evolved gas analysis, and residue analysis (Fourier transform infrared and scanning electron microscopy). The results showed that the intumescent flame retardant with the appropriate ammonium polyphosphate/hyperbranched triazine charring-foaming agent mass ratio (4/1) could significantly improve the flame retardancy of poly(1, 4-butylene terephthalate), and the highest Limiting Oxygen Index value and UL-94 V-0 rating was reached. The peak heat release rate and total heat evolved remarkably decreased, respectively, by 84% and 76% corresponding to poly(1, 4-butylene terephthalate). Thermogravimetric analysis results showed the synergistic effect between ammonium polyphosphate and hyperbranched triazine charring-foaming agent could enhance the char formation ability of composites. The results of gaseous products and residue char structure analysis indicated intumescent flame retardant influenced the decomposition behavior and promoted the formation and accumulation of phosphorous/azotic and polyaromatic char possessing high graphitization degree, which exerted a condensed-phase flame-retardant effect on the flame-retardant composites.

Mix design, properties and cost analysis of fly ash-based geopolymer foam

This study has investigated the joint effect of several mix parameters on the properties of foam geopolymers. The mix parameters analysed through a laboratory experiment of 54 different mortar mixes were, sodium silicate/sodium hydroxide mass ratio (2.5, 3.5, 4.5), activator/binder mass ratio (0.6, 0.8, 1.0), chemical foaming agent type (hydrogen peroxide (H2O2) and sodium perborate (NaBO3)) and foaming agent mass ratio content (1%, 2%, 3%). Properties, SEM and FTIR analysis and cost analysis are included. The results show that the sodium perborate over performs hydrogen peroxide leading to a lower overall thermal conductibility of foam geopolymers. Mixtures with a low thermal conductivity of around 0.1W/(m·K) and a compressive strength of around 6MPa were achieved. The cost analysis show that the foaming agents are responsible for a small percentage of foam geopolymers total cost being that the alkaline activators are responsible for more than 80%.

Location of dispersing agent in rubber nanocomposites during mixing process

In the present work, the development of morphology and selective wetting of nanoclay and carbon nanotubes (CNTs) in rubber nanocomposites were characterized qualitatively by means of the optical microscopy, TEM and AFM and quantitatively by means of the wetting concept. Carboxylated hydrogenated nitrile butadiene rubber (XHNBR), ionic liquid and ethanol were used as dispersing agent and they show very good effect on the macro- and microdispersion of nanofillers in different rubbers. It was found that the selective wetting of filler surface by the dispersing agent and rubber matrix is controlled by thermodynamic and kinetic factors. A model basing on surface energy data of polymer components (rubber and dispersing agent) and filler was introduced in order to determine the thermodynamic equilibrium state of filler wetting, which is found to be simultaneously determined by the filler–polymer affinity and the rubber/dispersing agent mass ratio. During the mixing process a replacement process of bound polymer components takes place on the filler surface until the predicted state is reached.

A Study on the Denitrogenation of Fushun Shale Oil

Removal of nitrogen compounds, especially basic nitrogen compounds, from Fushun shale oil was investigated. Different acidic reagents were chosen as the extraction reagent. The results showed that phosphoric acid-sulfuric acid complex reagent had the best nitrogen removal effect. The removal rate of basic nitrogen compounds increased with the increasing mass ratio of agent to oil, reaction temperature, reaction time, and settling time, respectively. When mass ratio of agent to oil was 1:1, reaction temperature was 60°C, reaction time was 20 min and settling time was 4 h with acidic reagent AB, removal rate of basic nitrogen compounds was up to 97.43%, and that of total nitrogen compounds was up to 38.25%, the yield of shale oil was 97.18%. The quality of shale oil had been significantly improved through this method.

New Technology of Preparation of TiO<sub>2</sub>/Tourmaline by Dry Coated Method and its Application in Coating

The high whiteness tourmaline composite powder was prepared with powder coating method in which TiO2 as the coating agent and the stearic acid as the coupling agent. The powder coating method system theoretical research was improved to aim at resolving the tourmaline’s limited applications in environmental health field due to the darker color. Theory and test results show that when the tourmaline and the coating agent mass ratio of about 2:1, the best results by scanning electron microscopy indicating that the tourmaline composite powder particle size prepared of this ratio is uniform with the composite powder whiteness of 74.5% which is 23.5% higher than building whiteness of the direct coating agent for mechanical mixing with tourmaline powder. After the composite powder was used to prepare the coating, the results show that the whiteness is 87.1% after formatting coating and negative ions incremental release over the 800 ions/cm3 when the content of tourmaline is 11%.

Production of granular activated carbons from loquat stones by chemical activation

This paper describes the production of activated carbons by chemical activation with KOH and NaOH of the chars obtained through carbonization of loquat stones at 600 °C. The chars in the 1.0–2.0 mm size range were activated at carbonization temperatures ranging from 600 °C to 1000 °C, heating rate of 10 °C/min and a char/chemical agent mass ratio of 1/2 under nitrogen flow. In addition, activated carbons were prepared from chars in the 1.0–2.0 mm and <0.5 mm size ranges at a char to KOH ratio of 1/4 at a carbonization temperature of 800 °C. Structural characterization of the activated carbons was performed by nitrogen adsorption at −196 °C.