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Zinc sulfide is a material that has many uses in various fields. Zinc sulfide is deriving from the mineral sphalerite. The purpose of this study was to evaluate the feasibility of producing zinc sulfide from zinc acetate and sodium sulfide using the precipitation-assisted ultrasonic radiation method. This method is the most efficient method for the synthesis of zinc sulfide nanoparticles, because it does not take much time and the resulting product is high. The evaluation was done from the engineering and economic perspectives. The feasibility analysis method from the engineering perspective was done by designing the initial production design on a large scale, whereas the analysis from an economic perspective was done by calculating various economic parameters, that is Gross Profit Margin, Cumulative Net Present Value, Internal Rate Return, Payback Period, Break Event Point, and Profitability Index. The engineering perspective showed that the production of zinc sulfide nanoparticles can be done on a large scale due to the commercial availability of materials and tools. Based on the economic evaluation, the production of zinc sulfide nanoparticles by precipitation-assisted ultrasonic method is ideal for an industrial scale. Earned increased profits over 20 years, the payback on investment costs lasted only two years. We hope that this study can provide references to readers, industry, and researchers regarding the feasibility analysis of the production of zinc sulfide nanoparticles using the precipitation-assisted ultrasonic radiation method

This study aims to evaluate the adsorption isotherm of carbon microparticles prepared from pumpkin (Cucurbita maxima) seeds for adsorbing curcumin (as a model of dye). The results were derived and compared using the kinetics approach based on several standard adsorption isotherm models, namely the Langmuir, Temkin, Freundlich, and Dubinin-Radushkevich models. The second aim is to evaluate the effects of carbon particle size (from 100 to 1000 mm) on the adsorption characteristics. The experimental results showed that the adsorption on the surface of carbon microparticles occurred in monolayer with a physical phenomenon. This is because the active areas are located only on the outer surface of carbon and no surface structure in the carbon is available. This is confirmed by the fact that the produced carbon has less porosity and the pores themselves are mostly produced from the release of inorganic contents during carbon synthesis, while the amount of inorganic content is very less. The confirmation of the adsorption profile was also achieved by testing various sizes of carbon microparticles. Smaller particles have direct impacts on the improvement of adsorption capacity, which is due to the existence of a larger surface area, a larger number of adsorption sites, and additional cooperative adsorption, i.e. adsorbate-adsorbate interaction. Understanding the adsorption phenomena occurring on carbon particles is useful for further developments and applications, such as those of catalysts and adsorbents, especially concerning the production of carbon materials from organic waste.

This study aims to investigate the effect of rice husks’ particle size on resin-based brake pad performance (i.e. compressive strength, puncture strength, mass loss, wear rate, friction coefficient, and heat resistance). Bisphenol A-epichlorohydrin and cycloaliphatic amine were mixed to form resin and used as the brake pad's base material. In the experiment, rice husk with a specific particle size (i.e., 250, 500, dan 1000 μm) was added to the resin. Rice husk has received considerable interest due to its lignin, cellulose, and silica content, making it suitable as friction material due to its ceramic-like behavior. The experimental results showed small rice husk particles improved compressive strength, puncture strength, and bulk density. This can be obtained from the analysis of the maximum compressive strength for brake pad supported by particles with sizes of 250, 500, and 1000 μm having values of 0.238; 0.173; and 0.144 MPa, respectively. In contrast, large particles formed coarse surfaces and pores, decreased mass loss rate, and improve friction properties (i.e. wear rate, friction coefficient). The friction coefficient values of brake pad supported by particles with sizes of 250, 500, and 1000 µm were, respectively, 0.2075; 0.2070; and 0.3379. Particle size affected interpacking, interfacial bonding, pores number and size, thermal softening, mechanical properties, and friction properties of the brake pad. Comparison between the prepared resin-based and commercial brake pad was also done, confirming the utilization of agro-waste as a potential alternative for friction material in the brake pad.

The purpose of this study is to demonstrate the synthesis of pyrazole-based ligands and to evaluate their catalytic properties in the oxidation reaction of catechol to o-quinone. The ligands were prepared via the condensation of (3,5-dimethyl-1H pyrazol-1-yl)methanol A with the appropriate primary amine. Four pyrazole-based ligands were successfully synthesized and characterized. These ligands provide one pyrazole sp2-nitrogen, one pyridine sp2-nitrogen, and one amine sp3-nitrogen, which were capable of coordinating to the metal. For evaluating the catalytic activity, the experiments were tested by varying the type of solvent, metal ion, anion in the metal salt, and ratios of ligands and metal salts. Excellent catalytic activities for the oxidation of catechol to o-quinone were obtained. The copper (II)-based complexes showed better reactions rates than those based on other metals (e.g., nickel, tin, and barium), which was due to the fact that the active catalytic site of the catecholase enzyme has two active sites from the existence of copper (II) ions. The composition ratios of ligands and metal salts as well as the type of anion in the metal salt bring impacts to the formation of complexes. We found also that the type of solvent contributes to the interaction and dilution of reactants in the solvent. This study demonstrated that the present ligands can be used as a model for further developments in catalytic processes relating to catecholase activity.

The purpose of this study was to demonstrate the adsorption of dye on carbon microparticles. We conducted two experiments: Understanding of the adsorption of dye on carbon microparticles. We used turmeric solution as a model of dye, in which this solution was contacted into commercially available carbon microparticles in the batch-typed adsorption reactor. The measurement results were then compared to several adsorption isotherm models, such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models; and finding teaching strategies to improve students’ understanding on the adsorption concept to students with special needs. As for the second part which is finding strategies to teach the obtained results and their concept of adsorption to students with special needs, we evaluated the strategies to eight students with intellectual disabilities in special schools in Kuningan District, Indonesia using a Single Subject Research method (equipped with pre-test, post-test, and experimental demonstration). The results showed that carbon can absorb dye and can be used as an alternative for wastewater treatment. The isotherm models have the linearity parameter R2 of above 50%, and the most suitable model is Freundlich. The models also confirmed favorable adsorption with multilayer structure and physical interaction between turmeric and carbon microparticles. Demonstrating experiments and informing the measurement results gave great impacts on students’ comprehension, in which they have better understanding about the concept of adsorption compared to the conventional teaching method.

This study evaluated isotherm adsorption of densed monoclinic tungsten trioxide (WO3) nanoparticles. To ensure the prepared particles were dense, experiments were conducted by combining ball-milling process and calcination of ammonium pentahydrate powder, in which all experiments were done with no additional chemicals or solvents. The adsorption process was carried out by adsorbing curcumin (as a model of adsorbate) in the batch process at ambient temperature and constant pH and the results was compared to several isotherm models: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models. To support the analysis, several characterizations were conducted: scanning electron microscope, X-ray diffraction and Fourier transform infrared. Experimental results showed that during the adsorption process, physical and chemical interactions occur simultaneously. The physical interactions happen when the adsorbate molecules attach directly to the surface of the adsorbent, forming monolayer adsorption. The chemical interaction is for the interaction between adsorbate molecules and occurs on above the formed main monolayer adsorption. The results were also completed with the proposal mechanism in the adsorption process. This study is important for supporting the fundamental researches in the photochemical reaction using WO3 catalyst.

The purpose of this study was to analyze the Economic Evaluation in the Production of Copper Nanoparticles (Cu-Nps) using Rongalite as Reducing Agent, an experimental method carried out in the perspective of engineering and economic evaluation. Technical analysis was performed using simple mass balance analysis, while economic evaluation was carried out using several economic parameters, including PBP, BEP, and CNPV. To support the analysis, all data is taken based on the available online shopping web. All calculations are carried out in ideal conditions for 20 years of production. Economic evaluation is carried out by giving 5 conditions (0%, 20%, 40%, 60%, and 80%) to the variable price variations in cost, sales, fixed cost, and labor. Economic evaluation analysis results show that price variations can affect the CNPV / TIC (%) curve to Life Time (year). In the variable cost, fixed cost, and labor variable price curve it is found that the condition of 0% is the highest curve compared to other conditions. While in sales price variations, the 80% condition is the highest curve. In conclusion, all price variation curves show profit. The benefits of this research are the large-scale economic evaluation data on Cu nanoparticle production.

The objective of this study was to investigate isotherm adsorption of carbon microparticles from pineapple peel waste. Carbon microparticles were prepared by carbonizing pineapple peel waste at 215-250°C and grinding using a saw-milling process. To investigate adsorption properties of carbon microparticles, experiments were done by evaluating adsorption of curcumin (as a model of adsorbate) in the ambient temperature and pressure under constant pH condition. To confirm the adsorption characteristics, carbon particles with different sizes (i.e., 100, 125, and 200 ?m) were tested, and the adsorption results were compared with several standard isotherm adsorption models: Langmuir, Freundlich, Temkin, and Dubinin- Radushkevich. To support the adsorption analysis, several characterizations (i.e., optical microscope, sieve test, and Fourier transform infrared analysis) were conducted. The adsorption test showed that the adsorption profile is fit to the Freundlich model for all variations, indicating the multilayer adsorption process on heterogeneous surfaces and interactions between adsorbate molecules. The results from other isotherm models also confirmed that the adsorption process occurs physically via Van der Waals force in binding adsorbate on the surface of adsorbent.

Soap pyrolysis is an interesting route for green jet fuel production because it is a simple process without required hydrogen supply and operated under atmospheric pressure. However, coke as an undesired product is often formed in high yield. In this investigation, pyrolysis of coconut oil soap was performed via catalytic routes in a batch reactor to avoid excessive coke formation. Two zeolite types, faujasite (H-Y) and mordenite (H-M), were evaluated as catalysts for pyrolysis. Catalyst loadings were studied for H-Y 20%, 40%, and 60%. Product analysis was performed by gas chromatography-mass spectrometry (GC-MS) to identify bio-oil components. Physical properties analysis was performed to determine the density and viscosity of the bio-oil product. The bio-oil produced from thermal process is composed of olefins C6–C18 (43.4%), ketones (38.6%), and paraffins C7–C18 (14.8%). Thermal pyrolysis showed low yield bio-hydrocarbon (olefins and paraffins) C8–C16 (11%) and high solid residual formation (23.4%). Catalytic pyrolysis using zeolites of reduced solid residual formation to 10.6% with high bio-oil yield; however, the undesired carboxylic acid products were produced. Catalyst loading effect shows that the higher catalyst loadings reduced solid residual formation with the carboxylic acid products increased. The highest bio-hydrocarbon yield (13.2%) was achieved over H-Y loading 20%. Soap pyrolysis over catalyst H-M showed high bio-oil yield (28.6%) and high bio-hydrocarbon yield (17.6%) as compared to the H-Y catalyst. The main products of pyrolysis bio-oil over H-M are olefins C6–C18 (48.9%), ketones (24.5%), and paraffins C7–C18 (15.9%). The range of bio-hydrocarbon produced was mainly similar to jet fuel. Catalytic pyrolysis route using zeolites improved the quality of bio-oil and reduced coke formation.

Gold nanoparticles are applicable in various engineering fields such as in biosensors, drug delivery, and tumor imaging. The objective of this study was to evaluate the scaling-up production of gold nanoparticles from laboratory to industrial scale. The evaluation was done from engineering and economic perspectives, in which several parameters including gross profit margin (GPM), and payback period (PBP) were analyzed. From the engineering evaluation, the result showed that the production of Nano gold is prospective using current technologies. To produce Nano gold, we could use chloroauric acid, sodium citrate, and sodium borohydride, in which these materials can be converted into gold nanoparticles. From the economic evaluation, the result showed that Nano gold production in industry scale can be profitable with a certain condition of raw material. It was shown that the breakeven point, payback period and gross profit margin could be achieved in 20 years.

The purpose of this study was to determine the feasibility of a project for the manufacture of magnesium oxide nanoparticles using the sol-gel method by evaluating both technically and economically. Evaluation from the technical side is determined by stoichiometric calculations and evaluation of the initial factory design, while the evaluation from the economic side is determined by several parameters to determine the benefits of the project to be established (Gross Profit Margin, Internal Rate Return, Break-Even Point, Payback Period, and Cumulative Net Present Values). Some of these economic evaluation parameters were analyzed to inform the production potential of magnesium oxide nanoparticles, such as determining the level of profitability of a project (Gross Profit Margin), predicting the length of time required for an investment to return the initial capital expenditure (Payback Period), predicting the condition of a production project in the form of a production function in years (Cumulative Net PresentValue), etc. The results of the technical analysis show that this project can produce 1,425 kg of magnesium oxide nanoparticles per day and the total cost of the equipment purchased is 45,243 USD. Payback Period analysis shows that the investment will be profitable after more than three years. To ensure project feasibility, the project is estimated from ideal to worst-case conditions in production, including salary, sales, raw materials, utilities, as well as external conditions such as taxes

This study aims to analyze the feasibility of a project for the production of magnesium oxide nanoparticles using precipitation methods on a large scale. The feasibility analysis of this project was determined using an evaluation from an economic and engineering perspective. Evaluation from an engineering perspective is determined by the evaluation of the initial factory design and stoichiometric calculations. Meanwhile, the evaluation from an economic perspective is determined by several parameters, such as Payback Period, Gross Profit Margin, Cumulative Net Present Value, etc. The analysis results show that the production of magnesium oxide nanoparticles using the precipitation method can be carried out on an industrial scale. In this project, 11,250 kg ofmagnesium oxide nanoparticles were obtained per day, and the total profit earned was 1,881,184,752.91 USD in 10 years. Payback Period analysis shows that the investment will be profitable after more than three years. To ensure project feasibility, projects are estimated from ideal to worst-case conditions in production, including salary, sales, raw materials, utilities, and external conditions such as taxes

This study aims to evaluate zinc oxide (ZnO) nanoparticles as a learning media to enhance students' understanding of View of Nature of Science and Technology (VNOST). The method used in this study: (i) understanding how to synthesize ZnO nanoparticles using a liquid-phase synthesis; (ii) implementation of ZnO nanoparticles to students and analysis their comprehension using Transcript Based Lesson Analysis (TBLA) on the Learning Video Recording and Adaptation Learning Transcript VNOST questionnaire, which is linked to the implementation and pattern of knowledge construction; and (iii) descriptive qualitative analysis to analyze the understanding of VNOST for each Category (Naïve, Has Merit and Realist). To support this study, several analyses were done, such as a scanning electron microscope and X-ray diffraction to characterize ZnO nanoparticles’ morphology and crystal structure, respectively, prior to giving this material for further learning to students. Experimental results showed that the use of ZnO nanoparticles is effective to improve the student comprehension. The understanding in the principle of nucleation and growth can be explained well since the reaction of ZnO is relatively fast. Students became more serious in listening during the learning process and more curious to study science and technology. Based on a comparative analysis of the initial and final ability of VNOST, it is proved that there was a change in students' views related to science and technology.

This study aims to determine the optimum binder composition and to teach students about the making of briquettes from a mixture of bamboo fiber with dried clove leaves. The methods are carbonization at 200-220�C for 7- 20 h, milling, sieving, stamping, and drying process with dextrin binder with concentrations of 20, 40, and 60%. The bamboo fibers and dried clove leaves are set at a composition ratio of 10:1. The particle size is mixed at the size of 600- 250 um; 250-89 um, and < 63 um. This research uses a learning video with an interesting subject about briquette production from bamboo fiber and dried clove leaves to analyze the effectiveness of learning video to 15 high school students, tested with 11 pre-test and post-test questions. To support the analysis, characterization of the briquettes is conducted. The experimental results show that briquettes made from bamboo fibers and dried clove leaves with a concentration of 60% have a good solidity, durability, fuel consumption, and moisture content, while the 20% have a good combustion ability. This research is important to reduce agricultural waste by recycling into briquettes for alternative fossil fuels, and the learning media through video enhances the comprehension of the subjects about biomass briquettes with dextrin binder.

The purpose of this study was to determine the feasibility of a zinc oxide (ZnO) manufacturing project through a green synthesis method using plant extracts Cassia fistula and then evaluate it from an engineering and economic perspective. Several economic evaluation parameters are analyzed to inform the potential production of ZnO nanoparticles, such as the length of time required for an investment to return the total initial expenditure (PBP), the condition of a production project in the form of a production function in years (CNPV), project benefits and so on. The results showed that the production of ZnO nanoparticles was very prospective. Technical analysis to produce 250 kg of ZnO nanoparticles per day shows the total cost of the equipment purchased to be 21,450.00 USD. PBP analysis shows that investment will be profitable after more than three years. This project can compete with PBP capital market standards because of the short investment returns. To ensure the feasibility of a project, the project is estimated from ideal conditions to the worst case in production, including labor, sales, raw materials, utilities, and external conditions.

This study is to evaluate the surface of AISI 316 as an electrode material for water electrolysis under various potassium hydroxide (KOH) electrolyte concentrations. In the experimental method, AIS316 electrode and KOH solution put into the water electrolysis system. The electrolysis system was combined with the hybrid car engine system that consumed a combination of hydrogen and gasoline as the fuel source. KOH solution concentration was varied from 0 to 0.53M, which was then used to evaluate the surface of AISI 316 electrode as well as hybrid car performances. The experimental results showed that electrolyte solution concentration is an important parameter to maintain high-efficiency hydrogen generation. The more KOH added it gave benefits for creating the more hydrogen gas. However, it brought problems in the electrode surface corrosion. The optimum condition to get more hydrogen gas but with less corrosion damage was obtained when performing the process with 0.40 M of KOH. Indeed, the result also found that the more hydrogen gas being produced has a direct correlation to the reduction of fuel consumption and exhaust gas emission (e.g., CO2, CO, and NOx).

Urea (CO (NH)2) is one of the compositions in making fertilizer. Fertilizer is crucial, especially for plant growth (affecting plant fertility). If a plant had urea fertilizer on the soil, nitrogen in the fertilizer releases quickly, and it will cause environmental pollution. Therefore, many studies want to develop urea fertilizer to be more efficient to use. The purpose of this review is to find the most appropriate method for the efficient use of urea as seen from the material used, the technique used, and the results obtained. This review shows that the most appropriate method is the slow release method with NaOH and fly ash ingredients. Because this method can increase the effective utilization of urea, reduce environmental pollution, and be relatively more straightforward, the raw material is more affordable and spread widely in the market.

Nanocomposites are a new material discovery in the 21st century. One of the nanocomposite materials which are useful in life is epoxy-clay nanocomposites. Epoxy clay nanocomposites have a reasonably wide application in industrial fields such as aerospace, defense, automobile, etc. The purpose of writing this review is to conduct a literature review on mechanical properties in various Cloisite as a filler of Epoxy-clay Nanocomposites. There are several examples of cloisite, namely Cloisite 10A, Cloisite 15A, Cloisite 20A, Cloisite 25A, Cloisite 30B, and Cloisite 93A. Cloisite has the advantage of producing mechanical properties, especially in the tensile modulus and strength, which is more increased than conventional reinforcing materials. These methods' synthesis results were then characterized using TEM, SEM, XRD, and other tests to determine their mechanical properties. The material parameters resulting from nanocomposites' synthesis are well seen from the high Tensile strength and modulus values. The highest increase in mechanical properties was found in the cloisite 93A by the ultrasonic synthesis method or mechanical stirring based on the study results.

This study aims to demonstrate the preparation of carbon microparticles obtained from red dragon fruit peel waste and their adsorption isotherm characteristics. The carbon microparticles were prepared by combining carbonization (at 250°C) and saw-milling process, and to get carbon microparticles with a specific size, sieve analysis was used. The adsorption isotherm was done by testing the adsorption ability of carbon microparticles with a specific size into curcumin solution in the batch-type reactor. The adsorption results were then compared to several standard isotherm models (i.e., Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models) for understanding what phenomena happen during the adsorption process. The adsorption analysis was also confirmed by testing several sizes of the carbon microparticles to predict the proposal mechanism in the adsorption process. The analysis results showed that the multilayer adsorption process occurs for all sizes in the micrometer range, and the process involves physical interactions between adsorbate and surface of adsorbent. The existence of multilayers is due to the possibility in the existence of porous structure in the carbon microparticles. This study is important for giving an alternative solution for reusable organic waste as well as supporting the fundamental researches in the further applications of carbon particles as catalyst and adsorbent.

The purpose of this study was to investigate influences of temperature on the conversion of ammonium tungstate pentahydrate (ATP) powder to tungsten trioxide (WO3) particles with controllable sizes, crystallinities, and physicochemical properties. In this study, we used a simple thermal decomposition method. In the experimental procedure, we explored the effect of temperature on the physicochemical properties of ATP by testing various heating temperatures (from 100 to 900 °C). The heated ATP samples were then characterized by a physical observation (i.e. color) and various analysis methods (i.e. a thermal gravimetric and differential thermal analysis, infrared spectroscopy, an X-ray diffraction, and a scanning electron microscope). Experimental results showed that increases in temperature had an impact to the decreases in particle size, the change in material crystallinity, and the change in physical properties (e.g. change of color from white, orange, to yellowish green). The relationships between the reaction temperatures and the physicochemical properties of the ATP were also investigated in detail along with the theoretical consideration and the proposal of the WO3 particle formation mechanism. In simplification, the phenomena can be described into three zones of temperatures. (1) Below 250 °C (release of water molecules and some ammonium ions).; (2) At 250-400 °C (release of water molecules and ammonium ions, restructurization of tungsten and oxygen elements, and formation of amorphous tungsten trioxide). (3) At higher than 400 °C (crystallization of tungsten trioxide). Since ATP possessed reactivity on temperature, its physicochemical properties changing could be observed easily, and the experimental procedure could be done easily. The present study will benefit not only for “chemistry and material science” but also potentially to be used as a model material for explaining the thermal behavior of material to undergraduate students (suitable used for a class and laboratory experiment and demonstration).

Ammonia is considered to be a potential medium for hydrogen storage, facilitating CO2-free energy systems in the future. Its high volumetric hydrogen density, low storage pressure and stability for long-term storage are among the beneficial characteristics of ammonia for hydrogen storage. Furthermore, ammonia is also considered safe due to its high auto ignition temperature, low condensation pressure and lower gas density than air. Ammonia can be produced from many different types of primary energy sources, including renewables, fossil fuels and surplus energy (especially surplus electricity from the grid). In the utilization site, the energy from ammonia can be harvested directly as fuel or initially decomposed to hydrogen for many options of hydrogen utilization. This review describes several potential technologies, in current conditions and in the future, for ammonia production, storage and utilization. Ammonia production includes the currently adopted Haber–Bosch, electrochemical and thermochemical cycle processes. Furthermore, in this study, the utilization of ammonia is focused mainly on the possible direct utilization of ammonia due to its higher total energy efficiency, covering the internal combustion engine, combustion for gas turbines and the direct ammonia fuel cell. Ammonia decomposition is also described, in order to give a glance at its progress and problems. Finally, challenges and recommendations are also given toward the further development of the utilization of ammonia for hydrogen storage.

The purpose of this study is to evaluate the economic feasibility of making copper nanowire using amino acids as a capping agent. The evaluation was conducted from two perspectives, namely engineering analysis and economic evaluation using parameters such as gross profit margin, payback period, breakeven points, and net present value. An economic evaluation was also carried out comparing the use of amino acids Glycine, Lysine, Proline, and Alanine to find out which amino acids were more profitable in the production of copper nanowire. Furthermore, the evaluation is done by estimating the ideal situation and several other state assumptions such as changes in raw material prices, labor costs, and also income tax. From the results of this study, Glycine is known as the most profitable amino acid to be used in this process. In addition, by using Glycine as an ideal condition, based on the results of the evaluation of all parameters, this project is classified as prospective to do. Although further studies must be carried out to develop this project, this study can be the basis for developing new methods of making copper nanowire on a large scale.

The introduction of an oxidation treatment to the synthesis of spherical and core–shell α″-Fe 16 N 2 /Al 2 O 3 nanoparticles (~62 nm) from plasma-synthesized core–shell α-Fe/Al 2 O 3 nanoparticles has been found to result in a high yield of α″-Fe 16 N 2 phase of up to 98%. The oxidation treatment leads the formation of a maghemite phase with open channeled structures along the c -axis, facilitating penetration of H 2 and NH 3 gases during the hydrogen reduction and nitridation steps. The saturation magnetization and magnetic coercivity of the core–shell α″-Fe 16 N 2 /Al 2 O 3 magnetic nanoparticles were found to be 156 emu/g and 1450 Oe, respectively. The detailed effects of the oxidation on the formation of α″-Fe 16 N 2 phase were investigated by characterizing the morphology (SEM, TEM and BET), elemental composition (EDX, EELS, and XAFS) and magnetic properties (Mossbauer and MSPS) of the prepared particles. The good magnetic properties obtained have the potential for future applications such as rare-earth-free magnetic materials.

Studies on the synthesis of polystyrene spheres have steadily increased in number. However, information regarding control of the physicochemical properties (i.e., size and charge) of polystyrene and its application as a template for the structure of materials remains limited. The purpose of our study was to synthesize surfactant-free polystyrene spheres with a controllable size (from 80 to 350 nm) and charge (from −50 to +40 mV) using a single-step and facile process, and to demonstrate their applications as templates for facilitating the production of porous particles with a tunable internal hole structure. Different from other polystyrene synthesis methods, the present synthesis procedure was conducted under surfactant-free conditions. To control polystyrene size and charge, several reaction parameters (i.e., temperature, styrene amount, and initiator concentration and type (cationic and anionic)) were investigated. To investigate the effectiveness of our synthesized polystyrene as a structure template, the synthesized polystyrene spheres were mixed with a host material and used in a spray method. As models of a host material, 15-nm silica nanoparticles and tetramethyl orthosilicate were used. These raw materials were selected because information about the exploitation of these materials remains limited. The results of the spray method showed that flexibility in the control of the size and surface charge of the polystyrene template made it possible to assist in the creation of particles with different hole configurations, including porous and hollow particles with control over the hole cavity, the internal structure, and the external shape. In addition, a theoretical explanation and a design for the mechanism of a hole-structured formation were also added, which would be important for the scaling-up prediction and estimation.

s Combining of tungsten trioxide (WO3) with titanium dioxide (TiO2) have been an interesting research subject because different from conventional TiO2 material, this composite can be used and activated under visible-light irradiation and has better photocatalytic efficiency. The purpose of this study was to synthesize composite WO3/TiO2 nanoparticles and to investigate the detail effect of composition of ammonium metatungstate (AMT, as a WO3 source) and titanium isopropoxide (TTIP, as a TiO2 source) in the wide range composition ratio on particle morphology (i.e.,outer size (from 20 to 90 nm), shape, and structure), crystallinity, and photocatalytic performance. To synthesize composite WO3/TiO2 nanoparticles, a flame-assisted spray-pyrolysis method was used. Experimental results showed that the amount of AMT (from 0 to 25 wt%) had shown a significant impact on the photocatalytic performance, however deviation of this amount had improve catalyst performance slightly. The change of photocatalytic activity is mainly influenced by band gap energy and surface area. To confirm the fundamental reason for this catalytic improvement, the effect of WO3 and TiO2 amounts on surface area, light absorbance, and charge separation analysis was investigated. The experimental results were also completed along with the proposal photocatalytic mechanism of particles containing WO3 and TiO2. In addition, although our present photocatalytic activity still needs to be improved, the present results open new information for creating more varied properties for application explorations.

Control of the shell structural properties [i.e., thickness (8-25 nm) and morphology (dense and raspberry)] and cavity diameter (100-350 nm) of hollow particles was investigated experimentally, and the results were qualitatively explained based on the available theory. We found that the selective deposition size and formation of the shell component on the surface of a core template played important roles in controlling the structure of the resulting shell. To achieve the selective deposition size and formation of the shell component, various process parameters (i.e., reaction temperature and charge, size, and composition of the core template and shell components) were tested. Magnesium fluoride (MgF2) and polystyrene spheres were used as models for shell and core components, respectively. MgF2 was selected because, to the best of our knowledge, the current reported approaches to date were limited to synthesis of MgF2 in film and particle forms only. Therefore, understanding how to control the formation of MgF2 with various structures (both the thickness and morphology) is a prospective for advanced lens synthesis and applications.

Four kinds of plasma-synthesized core–shell type α-Fe nanoparticles with various particle diameters, input composition of shell’s raw materials, and shell compounds were used to investigate dependence of these nanoparticle parameters on nitridation and magnetic performance. Effects of hydrogen-gas reduction conditions ( i.e., temperature and reduction time) prior to nitridation treatment were also investigated in detail. Experimental result showed that the nanoparticle parameters and the hydrogen reduction treatment influenced yield of α″-Fe 16 N 2 . Increases in particle diameter and shell amount resulted in the more difficulties in nitridation reaction because of the limitation in nitrogen diffusion phenomena. Changes in shell compound from Al 2 O 3 to SiO 2 resulted in the more difficulties in α″-Fe 16 N 2 phase formation. We also found that modification of reduction conditions affect the final product quality. We obtained that by optimization the nanoparticle parameters and the reduction process, the formation of nanoparticles with high yield of α″-Fe 16 N 2 (up to 99%) can be achieved. Finally, we found that for 43-nm core–shell Fe/Al 2 O 3 magnetic nanoparticles containing 10 wt% of Al 2 O 3 , the combination of 1.5-h reduction at 300 °C and 10-h nitridation at 145 °C gave the highest yield of α″-Fe 16 N 2 . The best saturation magnetization of 190 emu/g was achieved when using the amount of Al 2 O 3 of 20 wt%.

White light-emitting diodes offer the possibility of efficient, safe, and reliable solid-state lighting, and thus have various applications. Reported white light-emitting phosphors usually contain expensive rare-earth metals and are generally prepared by high-energy processes (e.g., >1000 °C, H2 and CO reduction atmospheres). These factors limit their applications. Therefore, preparing cost-effective white light-emitting phosphors from environmentally friendly processes is an important challenge. Herein, a direct white light-emitting aluminium–boron–carbon–oxynitride (AlBCNO) phosphor, which can be economically produced using low-energy methods (

Silver nanoparticles (Ag NPs) are the most frequently studied material with superiority as antibacterial that currently increasing the production of Ag NPs. Hence, feasibility study is needed for the development on the production of Ag NPs in industrial scale, especially in Indonesia and other developing countries. The chemical reduction with sodium citrate is used to produce Ag NPs. The purpose of this study is to analysis the prospect of large-scale industrial production in engineering perspective and economic evaluation. This study also gave recommendations for profitability of the production. Perspective of engineering in the production gave information about capability of large-scale production because the easy process and low-cost apparatuses of production can be done. Various economic parameters were used to completed the analysis. Then, the ideal condition to the worst issues of production was estimated to completed the calculation of economic evaluation by effects of raw materials. From this study, those all parameters gave positive result which mean it has good profitability. However, further analysis of strategies in sales and investment must be done in the future to developing the production of Ag NPs that promising in capability on large-scale production.

Information about correlation of material properties parameters (i.e., crystallite and particle sizes) and photocatalytic activity of tungsten trioxide (WO3) particles are still lacking. For this reason, the purpose of this study was to synthesize WO3 particles with controllable crystallite (from 18 to 50 nm) and particle sizes (from 58 to 677 nm) using a spray-pyrolysis method and to investigate correlation of crystallite/particle size and photocatalytic activity. To gain control of crystallite/particle size, synthesis temperature (120–1300°C) and initial precursor concentration (2.5–15 mmol/L) were investigated, which were then compared with the proposal of the particle formation mechanism. The results showed that both crystallite and particle sizes played an important role in photocatalytic activity. In this research, the optimum condition to produce the highest photocatalytic performance of WO3 particles was at the temperature of 1200°C (crystallite size: 25 nm), and initial concentration of 10 mmol/L (particle size: 105 nm). © 2013 American Institute of Chemical Engineers AIChE J, 60: 41–49, 2014

Tungsten trioxide (WO3) materials have excellent performance in transferring visible-light energy and are widely used in photocatalysis, solar cells, and hydrogen generation. However, WO3 is expensive and in short supply. It is therefore important to develop efficient materials that use smaller amounts of WO3. One strategy is to produce porous materials so that the entire area of the WO3 material can be used and activated effectively. In this study, we synthesized macroporous WO3 particles using a spray-pyrolysis method with colloidal templating. Ammonium tungsten pentahydrate (ATP) was used to produce WO3 without impurities, and polystyrene (PS) spheres were used to promote spherical macropore formation. The synthesized particles were characterized using thermogravimetric analysis, X-ray diffraction, nitrogen adsorption, scanning electron microscopy, and transmission electron microscopy (TEM). Several process parameters (i.e. initial precursor concentration and mass ratio between host and template) were investigated to get highly ordered porous particles with controllable porous structure and particle outer diameter. Photocatalytic analysis results showed that the amount of PS that provided the optimum photocatalytic enhancement. Our results showed that a PS/ATP mass ratio of 0.60 provided WO3 particles with a photocatalytic rate 2.5 times that of dense WO3. TEM analysis showed that highly ordered macropores were produced, enabling better penetration and interaction of molecules and light in the deepest part of the active catalyst, resulting in enhancement of the photocatalytic rate. This method will be useful for large-scale synthesis of small amounts of WO3 with high photocatalytic performance.

Studies on synthesis of hollow particles have received considerable attention because these particles can be used for wide range applications. However, current methods have problems in the agglomeration phenomena and must be proceeded in the multi-step, complicated, and time-consuming procedures. Therefore, purpose of this study is to show a new method to produce agglomeration-free hollow silica particles with spherical shape and controllable diameter (from 90 to 200 nm). Different from other reports that typically used a liquid-phase synthesis method, we used an electrospray deposition followed by template removal process. Polystyrene and silica were used as models of template and host material, respectively. The prepared particles were characterized using a fourier transform infra red and a scanning and a transmission electron microscopes. Experimental results showed that size and agglomeration condition of hollow particles were controllable only by changing core diameter, electrospray flow rate, and precursor concentration. The successful and unsuccessful condition was also described.

A new electrospray system has been successfully developed by employing a proportional–integral–derivative control action to maintain an electric current at a certain value. A polymer precursor solution containing polyethylene glycol was used to examine the performance of this system. The result showed that cone-jet geometry could be controlled easily by adjusting the electric current. The length of the cone-jet decreased as the electric current was increased, in a correlation that followed power law. We also found that the cone-jet observed during electrospraying was stable and robust with no disturbance during long periods of use (up to 4000 s). The present study is very useful for further development of high precision aerosol generators and particle synthesis.

A new method for the preparation of agglomeration-free core-shell polystyrene (PS)/silica particles under an additive-free process was proposed. Different from other reports that typically used a liquid-phase synthesis method, we used an electrospray deposition method. While other methods use additive to bridge and paste the shell component on the core material, we preferred to use the effect of electrostatic charge phenomenon to make successful coating process. The particles with agglomeration-free and controllable size (from 80 to 300 nm) and morphology were successfully prepared. The control of particle size and morphology was also achieved by only changing the PS core size and the silica-to-PS ratio, respectively. The successful and unsuccessful condition was also described, which would be important for further developments (i.e. scale up process). We believe that this research would be useful for various coating applications.

Rare-earth-doped yttrium aluminum garnet (YAG:RE) phosphors have good photoluminescence (PL) properties and are widely used in light-emitting diodes. However, the RE elements used in these phosphors are expensive and in short supply. It is therefore important to develop phosphors that contain smaller amounts of RE materials. One strategy is to produce nanocomposite phosphors in which a cheaper and more readily available material is used as a matrix for an RE oxide. In this study, we produced a YAG:Ce/SiO2 nanocomposite using a sol–gel method; poly(ethylene glycol) and urea were added to promote micelle formation and agglomeration, respectively. The nanocomposites were characterized using X-ray diffraction, scanning and transmission electron microscopies (TEM), and energy-dispersive X-ray spectroscopy. We determined the concentration of SiO2 that provided maximum PL enhancement, and used geometrical models as well as the characterization results to propose an explanation for this enhancement. Our results showed that an SiO2 concentration of 10 vol% provided a PL intensity 120% that of pure YAG:Ce. TEM analysis showed that SiO2 nanoparticles covered the voids between the single grain boundaries of the YAG:Ce crystals, thereby inhibiting light scattering, resulting in enhanced PL. This method will be useful for large-scale synthesis of low-RE, high-PL phosphors.

In this study, spherical cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor particles were directly synthesized by a modified sol–gel method using poly(ethylene glycol) (PEG) and urea. In the absence of PEG and urea, only irregularly shaped particles were obtained through aggregation and sintering after solvent evaporation. In contrast, adding both PEG and urea to the precursor solution resulted in the formation of spherical particles. The spherical morphology was attributed to micellization by PEG and micelle agglomeration by urea in a liquid phase. Scanning electron microscopy and X-ray diffraction analyses revealed that the spherical particles were of size around 5 μm, and the obtained crystal was pure a YAG phase. The emission band of the YAG:Ce phosphor prepared at 1600 °C for 2 h was observed at 530 nm under excitation at 470 nm, and the maximum internal quantum efficiency was found to be 57.6%.

Silica is the most abundant components in the earth's crust and is made by way of synthesis for use in the application of technology. Silica are generally found commercially as alkoxysilane compounds (i.e such as tetraethylorthosilicate (TEOS), sodium silicate, and tetramethylorthosilicat). However, these compounds can have a negative impact on health. Thus, further approaches to find the source of silica that is safer, cheaper, and more environmentally friendly is inevitable. However, not all summary journals are thoroughly discussed the silica sources. Further, method of isolation and application of the silica from agricultural waste is limited. This paper reported studied several sources of silica derived from agricultural waste, such as rice husk, rice straw, corn cobs, and bagasse. In addition, this paper discussed also about the method of isolation of silica from agricultural waste, and its application as a catalyst.

Isolation of needle-shaped bacterial cellulose nanocrystalline with a diameter of 16-64 nm, a fiber length of 258-806 nm, and a degree of crystallinity of 64% from pineapple peel waste using an acid hydrolysis process was investigated. Experimental showed that selective concentration of acid played important roles in isolating the bacterial cellulose nanocrystalline from the cellulose source. To achieve the successful isolation of bacterial cellulose nanocrystalline, various acid concentrations were tested. To confirm the effect of acid concentration on the successful isolation process, the reaction conditions were fixed at a temperature of 50°C, a hydrolysis time of 30 minutes, and a bacterial cellulose-to-acid ratio of 1:50. Pineapple peel waste was used as a model for a cellulose source because to the best of our knowledge, there is no report on the use of this raw material for producing bacterial cellulose nanocrystalline. In fact, this material can be used as an alternative for ecofriendly and cost-free cellulose sources. Therefore, understanding in how to isolate bacterial cellulose nanocrystalline from pineapple peel waste has the potential for large-scale production of inexpensive cellulose nanocrystalline.

Studies on the synthesis of organic particles for template applications for facilitating the production of hollow particles have attracted tremendous attention. The unavailability of the commercial templates with a positive zeta charge is the main reason for this demand of study. The purpose of this study was to spotlight the synthesis of pure and cationic polystyrene (PS) particles with controllable size (from 30 to 300 nm) using a single step and relatively simple and cheap process and to demonstrate their application as the template in the production of hollow inorganic particles. Different from other methods, the synthesis method was based on the polymerization of styrene monomer in an aqueous solution system in the absence of any additional components (polymers, surfactants, chemicals, etc.) under 2,2-azobis (isobutyramidine) dihydrochloride (AIBA) as a cationic initiator to facilitate the creation of PS with a positive zeta charge. Precise control of the PS particle size in the nanometer range was achieved by the adjustment of reaction parameters (i.e. temperature, and styrene and AIBA concentrations). The size of the PS particles was proportional to the composition of styrene and the amount of initiator but had an inverse-proportional trend to the temperature. In addition, we also found that the styrene amount had more effect than the initiator (more than 4 times) on controlling PS size. Since an FTIR pattern and a micro-Raman spectrum results detected that the prepared PS particles had pure composition and homopolymer in spite of varying reaction parameters, the change of the particle size was due to changes in nucleus formation and particle growth rates. Flexibility of the process in the nanometer size control also drove to the devise of an equation to predict the particle size, which would be important for further scale-up development. Finally, the loaded positive zeta charge in the PS made it possible to assist the production of hollow inorganic particles (e.g. tungsten oxide, zirconia, and silica), in which this production could not be achieved when using commercial PS particles, verified by the particle formation mechanism hypothesis.

An ordered porous monolayer was successfully prepared using a dual-speed spin-coating with colloidal templates. The facile and rapid production was effective when a combination of 5-nm silica (as a model of an inorganic nanoparticle) and 410-nm polystyrene (PS) spheres (as a model of the template) were spin-coated to produce a composite silica/PS film. Heat treatment was then used to remove the PS, producing the porous film. The porous monolayer with a highly ordered porous structure could be obtained, which would not be realized using the current spin-coating methods that utilize single-spinning speed technique. The pore size and shape (spherical) were identical to the initial template, giving a potential way for further developments (e.g. control of pore size). The theoretical explanation and mechanism of porous formation were also added, which would be important for the scaling-up prediction and estimation. Sufficient numbers of pores made it possible to produce a material with a high porosity, an ultralow density, and an ultralow refractive index because the pores allocated free space, which was confirmed by calculation.