Characteristics of High Content Steel Briquettes Using Nanosized Solid Binders.

In this study, we investigated the characteristics of high-content steel briquettes produced using various nanoscale solid binders and steel byproducts (SS, SCS, SLD, and BSD). The average particle size was 0.171 nm for S5, 0.065 nm for S1, 0.058 nm for S4, and 0.040 nm for S2 and S3. The SEM-EDS analysis of the solid power binder resulted in mostly rectangular images. The compressive strength of the high-content steel briquettes was 120 kgf/cm², with the highest HSL1 using S4 binders. The compressive strength of the high-content steel briquettes was in the order of HSS4 > HSS1 > HSS3 > HSS5 > HSS2.

Oxidation of Acetaldehyde Over Cobalt Supported on Nanosized Carbon Black Catalysts.

In this study, we investigated the oxidation of acetaldehyde over Co/carbon black catalysts. All experiments were conducted in the temperature range of 200-440 °C, at an acetaldehyde concentration of 0.94 mol% in air, and using Co loading amounts in the range of 2-60 wt%. The nanosized carbon black and Co/carbon black catalysts were characterized using thermogravimetric analysis (TGA) and X-ray diffraction (XRD) analysis. The TGA data revealed that the nanosized carbon black was stable at high temperatures (600 °C), and the XRD results indicated that Co/carbon black was deteriorated and Co oxides, such as Co3O4, were formed. The addition of Co3O4 crystallites on the catalyst surface provided the greatest increase in catalytic activity. The catalytic activity of the supports used in this study for the acetaldehyde oxidation reaction increased as follows: SiO2 < TiO2 < carbon black < SiO2-Al2O3. The experimental results and economic considerations revealed that nanosized carbon black could be effectively used as catalyst support for the oxidation of acetaldehyde. The activity of the Co/carbon black catalysts varied with the Co loading amount, and the optimum Co loading amount was 10 wt%.

Effect of Cobalt Oxides on the Catalytic Combustion of Odor.

The catalytic combustion of acetaldehyde was studied using various types of Co oxides and Co-PC. The Co oxides and Co-PC were characterized using an X-ray diffractometer (XRD), X-ray photo-electron spectroscopy (XPS), and a particle sizing analyzer. The Co-PC and CoO were converted into Co3O4 under an air atmosphere at 450 °C, and the results were confirmed using the XRD and XPS. According to the pretreatment of the Co-PC and Co oxides, the conversion of acetaldehyde increased. The order of particle size for both fresh and pretreated samples is summarized as follows: CoO < Co-PC < Co3O4 powder < Co3O4 (99.995%). For all samples, acetaldehyde was not observed at temperatures above 320 °C owing to complete combustion. The conversion of acetaldehyde in the samples was affected by the fresh state of the Co oxides and the space velocity. The catalytic activity depended on the chemical state of the Co oxides and the surface concentrations of Co, O, and N.

Preparation of Mesoporous Gamma Alumina Derived from Waste Can for Nutrient Recovery Process.

Mesoporous gamma alumina (MGA) was synthesized using aluminum trash containers by a low temperature hydrothermal method for effectively removing phosphate from wastewater. The effects of precursor concentrations in gel precipitation process over the pore size and surface area of MGA were investigated in detail. The phosphate removal by prepared MGAs were rigorously investigated through adsorption isotherms and kinetics of phosphate.

Reduction of Fluoride in Water Phase by Micro-Nano Bubble Pretreatment Process.

Fluoride is important to aquatic environment and health aspects, and the optimal fluoride concentration in water is below 1 mg/L. In this study, the micro-nano bubble pretreatment was applied to remove fluoride ions in the water phase. The pH control by calcium hydroxide (Ca(OH)2), and coagulation processes with poly aluminum chloride (PAC), aluminum sulfate (Alum), F900 and two kinds of polymer named as A-polymer and A430P polymer were applied for the pretreated wastewater. In results, the combination of PAC and A430P polymer with micro-nano bubble pretreated wastewater showed a higher fluoride removal than the case of other combinations. In chemical oxygen demand (COD) removal, the combination of Alum and A430P polymer with micro-nano bubble pretreated wastewater showed the best removal efficiency (64.6%) while the COD removal without pretreatment was 71.4% for fluoride and 57.2% for COD.

Nano-Sized Fume Biogas Production from Food Waster Using Semi-Continuous Anaerobic Digester.

In this study, the nano-sized fume biogas production from food waste was investigated using lab scale semi-continuous stirred tank reactor (SCSTR) at 35 °C with 30d HRT and 30L working volume. The mesophilic digestion test was performed with three different feed materials (food waste) and food to microorganism (F/M) ratios (0.13, 0.34, and 0.27) in the same experiment. The results showed that the F/M ratios significantly affected the biogas production rate. The highest production rate was obtained at F/M ratio of 0.13. Nano-sized fume biogas produced in anaerobic digestion consists of 68.7% CH4, 31.2% CO2 and 30~200 nm particle. The average nano-sized fume biogas and methane production of digester were 29.96 L/Kg versus day-1 and 20.58 L/Kg versus day-1, respectively. The CH4 could be calculated as the heat energy 1.85 Kcal/Kg VS day-1. The digestion was operated without addition of chemicals or nutrients into the system.

Environmental Applications of Nano-Sized Recycled Aggregates: The Effect of Sterilization and Adsorption.

To evaluate the sterilize efficiency of nano-sized recycled aggregates (RAs), several types of RAs were examined for the purpose of environmental stamping out procedure. The poultry (e.g., chicken) was selected as a target livestock of epidemic disease, and the blast furnace slag (BFS), fly ash (FA), slaked lime (SL), nano-cerium (n-Ce) and shell (Sh) were used as the RAs materials. The fermented solution of effective microorganisms (EM) was added to decompose the target livestock. Various kinds of lab-scale reactor were operated to examine the effects of RAs volume; high and low volume of RAs (e.g., 1.89 w/v% and 1.14 w/v% of RA in solution, respectively), and the effects of EM concentration (e.g., concentrated solution (100%) and diluted solution (12.5%)) with tested in different reaction time. The number of microorganisms after batch tests was counted for the sterilized effects of RAs, and organic matters (e.g., chemical oxygen demand (COD)) and inorganic matters (e.g., suspended solids (SS), heavy metals and potential ions) were analyzed before and after adsorption process. The cases of SL and n-Ce showed high removal of microorganism in the batch of high concentrated EM for 20 days. However the other RA materials were less effective on the sterilization especially in lower volume of RAs. In diluted EM (e.g., 12.5%) tests, most RAs have high sterilization efficiencies in the short periods of batch reaction regardless of RAs types, and it was more effective with longer reaction time. The BFS and n-Ce exhibited higher surface area than others and they adsorbed highly heavy metals in water. The results suggested that the concentration of target organism was the most important to determine sterilization and adsorption properties of RAs.

The Effects of Pore Volume and Compressive Strength on the Nano-Sized Recycling Material Mixtures.

In this study, the effect on pore volume and compressive strength was investigated using nano-sized blast furnace slag (BFS), fly ash (FA), and desulfurized gypsum (DG). In the chemical compositions of BFS and FA, the sum of the four ingredients, CaO, SiO2, A12O3, and MgO were shown to account for 97% and 87%, respectively. Particles smaller than 50 nm were shown to be distributed in the range of 47.9% to 50.7%, particles larger than 50 nm but smaller than 100 nm were distributed in the range of 19.0% to 29.1%, and particles sized 100 nm or larger were shown to be distributed in the range of 21.3% to 23.2%. As a result of analysis carried out using an scanning electron microscope (SEM), it was found that BFS, FA, and DS are mixtures of smooth spherical particles and unevenly shaped materials. As to the dependence of pore volume, which depends on pore size and compressive strength, the volume of pores of sizes between 3 and 10 nm showed a proportional trend where volume increases and, as a result, compressive strength also increases as the material age increases. Moreover, the volume of pores sized between 10 and 100 nm showed an inversely proportional trend where volume decreases and, as a result, compressive strength also decreases as the material age increases.

Adsorption of Magnesium Sulfate from Desulfurization Industrial Wastewater by Nano-Cerium Loaded Recycled Aggregates.

In this research, the recycled aggregates (RAs) from blast furnace were solidified with nano-cerium (Ce), and applied to reduce the ionic species (e.g., magnesium sulfate) in the desulfurization industrial wastewater. Static batch experiments were performed based on different loading of recycled aggregates. Sulfate sorption isotherm studies were performed by Langmuir adsorption model. The physical morphologies were determined using scanning electron microscope. The results presented that the partial ions were captured with the different loading of the recycled aggregates during the batch tests. It was observed that 8 hr batch reaction equilibrated the electrical conductivity reduction, and 13% mass loading was estimated an optimal dosage of adsorbent. This study showed the nano-Ce loaded RAs could reduce ionic species in wastewater, and expected to be an economical adsorbent for wastewater treatment process.

Properties of Pd, Pt and Ru-Based Catalysts in Catalytic Oxidation of Methanol.

Catalytic oxidation of methanol was investigated using Pd, Pt and Ru-based catalysts. Experiment was conducted at reaction temperature of 100-220 degrees C with methanol concentration of 3000 ppm and gas hourly space velocity (GHSV) of 16,000 hr(-1). Catalysts were characterized by using Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), field transmission electron microscopy (FE-TEM) and temperature programmed reduction (TPR). Based on complete oxidation temperature of methanol, the activity order was: 0.16 wt% Pd /0.16 wt% Pt/0.16 wt% Ru/gamma-Al2O3 > 0.5 wt% Pt/gamma-Al2O3 > 0.5 wt% Ru/gamma-AlO3 > 0.5 wt% Pd/gamma-Al2O3. Therefore, the activity of ternary metal-based catalyst was superior to single metal-based catalyst.

Impact of Nano-Pore Structure in Harden Non-Sintering Cement.

This study investigates the nano pore structure of non-sintering cement (NSC) matrix. The result of pore structure properties showed no considerable difference in the total pore volume, but presented a large distinction in distribution of pore diameter by cement mixing ratio. The pore-diameter of NSC paste shows that occupation ratio of pore diameter below 10 nm was larger and was smaller than ordinary Portland cement (OPC) and blast-furnace slag cement (BSC) at pore diameter of over 10 nm. The reasons are due to the hydrate such as C-S-H gel and ettringite which formed dense nano pore structure of NSC matrix.

Preparations of Platinum Nanoparticles and Their Catalytic Performances.

This work investigates the effect of reducing agents and stabilizing agent on the preparation of platinum nanoparticles. We used H2PtCl6 as a precursor and hydrogen and sodium borohydride as reducing agents to prepare colloidal platinum nanoparticles. Polyvinylpyrrolidones (PVPs) is used as a stabilizing agent. Hydrogen and sodium borohydride are used as reducing agents. The prepared platinum nanoparticles are characterized by transmission electron microscopy (TEM) and X-ray diffractometer (XRD). The concentrations of the precursor and the stabilizing agent influence the size of platinum nanoparticles, while the reducing agents influence the morphologies and structures of platinum nanoparticles. Supported platinum catalysts (CPt-NaBH4, CPt-H2) are prepared from colloidal platinum nanoparticles and γ-Al2O3. For comparison, another supported platinum catalyst (IPt) is prepared by the conventional impregnation method with an aqueous H2PtCL6 solution and γ-AL2O3. The catalytic activities of CPts are superior to that of IPt on the basis of benzene conversion.

Influence of a surfactant and reducing agent on preparation of palladium.

We investigated the influence of a surfactant and reducing agent on the preparation of palladium nanoparticles, characterizing the prepared palladium nanoparticles by Transmission Electron Microscopy (TEM), and X-ray diffractometer (XRD). Colloidal palladium nanoparticles are prepared using PdCl2 as a precursor and polyvinylpyrrolidone (PVP) as a surfactant. In addition, hydrogen and sodium borohydride are used as reducing agents are used to characterize the prepared palladium nanoparticles. The concentrations of a precursor, a surfactant and its molecular weight affect the size of palladium nanoparticles, while the reducing agents influence the morphologies and structures of palladium nanoparticles.

Aged nano-structured platinum based catalyst: effect of chemical treatment on adsorption and catalytic activity.

To examine the effect of chemical treatment on the adsorption and catalytic activity of nanostructured platinum based catalyst, the aged commercial Pt/AC catalyst was pretreated with sulfuric acid (H2SO4) and a cleaning agent (Hexane). Several reliable methods such as nitrogen adsorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and inductively coupled plasma (ICP) were employed to characterize the aged Pt/AC catalyst and its chemically pretreated Pt/AC catalysts. The catalytic and adsorption activities of nano-structured heterogeneous Pt/AC catalyst were investigated on the basis of toluene oxidation and adsorption isotherm data. In addition, the adsorption isotherms of toluene were used to calculate the adsorption energy distribution functions for the parent catalyst and its pre-treated nano-structured Pt/AC catalysts. It was found that sulfuric acid aqueous treatment can enhance the catalytic performance of aged Pt/AC catalyst toward catalytic oxidation of toluene. It was also shown that a comparative analysis of the energy distribution functions for nano-structured Pt/AC catalysts as well as the pore size distribution provides valuable information about their structural and energetic heterogeneity.

The effect of microwave-assisted for photo-catalytic degradation of rhodamine B in aqueous nano TiO2 particles dispersions.

The photo-catalytic decomposition of rhodamine B was examined in aqueous nano TiO2 particles dispersions to assess effects of the microwave radiation assisted photo-catalytic process driven by UV radiation. The results of photo-catalytic degradation of rhodamine B showed that the decomposition rate increased with the microwave intensity, UV intensity, TiO2 particle dosages and the circulating fluid velocity. Addition of oxygen gas in the photo-catalytic degradation of rhodamine B increased the reaction rate. The effect of addition of H2O2 was not significant when photo-catalysis was used without additional microwave radiation or when microwave was irradiated without the use of photo-catalysts. When H2O2 was added under simultaneous use of photo-catalysis and microwave irradiation, however, considerably higher degradation reaction rates were observed. This study demonstrates that the microwave irradiation can play a very important role in photo-catalytic degradation.

The removal of nitrate by nanoscale iron particles produced using the sodium borohydride method.

This study was conducted to investigate removal of nitrate by nanoscale zero-valent iron (ZVI) particles in aqueous solution. ZVI particles was produced from wasted acid that is by-products of a pickling line at a steel work. The reaction activity of ZVI particles was evaluated through decomposition experiments of NO3-N aqueous solution. Addition of a larger amount of ZVI particles resulted in a higher decomposition rate. ZVI particles showed higher decomposition efficiencies than commercially purchased ZVI particles at all pH values. Both ZVIs showed a higher decomposition rate at a lower pH. Virtually no decomposition reaction was observed at pH of 4 or higher for purchased ZVI. The ZVI particles produced directly from wasted acid by the sodium borohydride method were not easy to handle because they were very small (10-200 nm) and were oxidized easily in the air.

Assessment of Microwave/UV/O(3) in the Photo-Catalytic Degradation of Bromothymol Blue in Aqueous Nano TiO(2) Particles Dispersions.

In this study, a microwave/UV/TiO(2)/ozone/H(2)O(2) hybrid process system, in which various techniques that have been used for water treatment are combined, is evaluated to develop an advanced technology to treat non-biodegradable water pollutants efficiently. In particular, the objective of this study is to develop a novel advanced oxidation process that overcomes the limitations of existing single-process water treatment methods by adding microwave irradiation to maximize the formation of active intermediate products, e.g., OH radicals, with the aid of UV irradiation by microwave discharge electrodeless lamp, photo-catalysts, and auxiliary oxidants. The results of photo-catalytic degradation of BTB showed that the decomposition rate increased with the TiO(2) particle dosages and microwave intensity. When an auxiliary oxidant such as ozone or hydrogen peroxide was added to the microwave-assisted photo-catalysis, however, a synergy effect that enhanced the reaction rate considerably was observed.

Regeneration of spent three-way catalysts with nano-structured platinum group metals by gas and acid treatments.

The influence of physicochemical treatments on the catalytic activity of the spent nano-structured three way catalysts (TWCs) was examined to evaluate the possibility of using spent TWCs for removing VOCs. Thermal gases and acid aqueous solutions were used to regenerate the spent nano-structured TWCs. The characterization of the spent catalyst and its modified forms was carried out by using XRD, TEM, ICP, and N2 adsorption-desorption isotherms. The catalytic activity tests revealed that the spent nano-structured TWCs have a great potential for removing toxic compounds. The activities of catalysts were also found to be highly dependent on the treatment conditions. The acid aqueous treatments were very useful for improving the catalytic activity because they removed various contaminants such as fuel additives, lubricant oil additives, and metallic compounds. However, the thermal gas treated TWCs were less active than the parent TWCs. Furthermore, the activities of the catalysts treated with acids were closely connected with the remaining Pt/Al ratios.

Adsorption and conversion of various hydrocarbons on monolithic hydrocarbon adsorber.

Adsorption and conversion of various hydrocarbons on monolithic hydrocarbon adsorbers were studied using a new experimental model, temperature-programmed adsorption (TPA). In this study, methyl alcohol, acetone, acetaldehyde, 2,2,4-trimethylpentane, n-octane, and toluene were chosen as model hydrocarbons for cold start of a vehicle. The effect of the hydrocarbon components and oxygen concentration on the TPA curve was investigated. Depending on the presence of O(2), the adsorbed and desorbed amounts of the hydrocarbons were decreased, while the conversion efficiency of the hydrocarbons was increased. In the case of hydrocarbons containing oxygen, the thermal decomposition appeared to be in the order methanol, acetaldehyde, and acetone.