Search

A paper battery is a 6 cm × 4 cm × 1 mm dimension battery that uses CuCl as a cathode, magnesium as an anode, and urine as an electrolyte. CuCl2 dan CuSO4 as used to synthesis CuCl was analyzed. A simple and cheap sandwiched fabrication model has been identified using the low-cost CuCl synthesis process. This paper battery has passed experimental testing and delivers the best power generation at 169,588 mW and continuously up to 4 hours. Voltage also measured and provided a stable voltage at least for 6 hours at 582.667 mV. Method 2 of using CuSO4, which has price lower than CuCl2 showed better power generation and stability.

We have developed a flexible reduced graphene oxide (RGO) temperature sensor on filter paper based cellulose substrate using vacuum filtration method. One of the most commonly used synthesized methods for RGO thin films is vacuum filtration process. It has several advantages such as simple operation and good controllability. The structural analysis was carried out by FE-SEM, in which the surface morphology images confirm the formation of RGO nanostructures on the filter paper substrate. It was observed that the pores of the filter paper were completely filled with the RGO material during the filtration process, subsequently the formation of continuous RGO thin films. As a results, the RGO films exhibits a piezoresistive property. The resulted RGO based films on the filter paper reveals the semiconducting behavior having sensitivity of 0.278 Omega/degrees C and negative temperature coefficient (NTC) about -0.00254 Omega / Omega /degrees C. Thus, we demonstrate a simplified way for the fabrication of RGO films on filter paper that possesses better and easier measurable macroscopic electrical properties. Our approach is for easy way of electronics, cost-effective and environment friendly fabrication route for flexible conducting graphene films on filter paper. This will enable for the potential applications in flexible electronics in various fields including biomedical, automobile and aerospace engineering.

A simple and economical method has been used to grow macroscopically reduced graphene oxide (rGO) paper for device application. Synthesized paper has been characterized by different experimental techniques namely SEM, TEM, Raman and UV-Vis spectroscopy respectively. Besides these, temperature dependent electrical studies of rGO paper have also been carried out.

Graphene is one atom thick two dimensional material with unusual mechanical, electrical, thermal and optical properties. Graphene, on larger scale is produced through reduction of graphene oxide which in turn is synthesized by chemical oxidation of graphite. Generally large area graphene oxide paper can be easily fabricated by solution filtration process, spin casting method and Langmuir-Blodgett assembly. In present study graphene oxide was synthesized by modified Hummers method. Free standing graphene oxide paper (GOP) was developed by simple drying of graphene oxide suspended in water followed by reduction by thermal treatment to synthesize free standing conducting graphene paper (Thermally Reduced Graphene Paper, TRGP). Thermal reduction was carried out for 30, 60, 90 and 120min and samples referred as TRGP_30, TRGP_60, TRGP_90 and TRGP_120 respectively. XRD results show decrease in inter layer spacing (d002) from 0.87 nm to ∼0.35 nm after reduction of GO paper. This shows gradual removal of oxygen fu...

Here, we presented a novel, cost effective approach to fabricate flexible piezoelectric nanogenerator (NG) consisting of ZnS nanowires (NWs) grown upon cellulose. An output voltage of 4 V is generated from the nanocomposite paper (NC-paper) based NG. Subsequently, it has the capability to power Light Emitting Diode (LED) and charging up capacitor. The corresponding energy stored in the capacitor (1 µF) is 16 µJ. Thus, the fabricated NC-paper based NG can be used for smart textile structures, wearable and self-powered nanodevices.

The commercial telecommunication system in future would explore the electromagnetic spectrum with higher frequency than used now, because it requires higher speed of transmission data. Using the millimeter waves (mmW) with frequency ranging from 30 to 300 GHz, such requirement could be fulfilled. The upcoming 5G cellular technology is expected to use frequency 30 GHz or higher. Then materials with a specific characteristic at the mmW range are interesting to be explored and investigated. Here, we report the synthesis process of graphene/TiO2 deposited on paper and their transmission characteristics to the electromagnetic energy at frequency 27-40 GHz (Ka-Band). The reduced graphene oxide (rGO) was synthesized by a modified Hummers method with introduction of microwave irradiation in the process. rGO and TiO2 were mixed in ethanol solution and deposited on the paper by a spraying technique. Transmission coefficient of electromagnetic wave energy at Ka-Band was measured by using the millimeter vector networ...

The Young’s modulus of buckypaper (BP) was improved via the addition of carbon nanocoils (CNCs). The Young’s modulus was the highest when the added amount of CNCs of the mass of the bucky paper was 11.9%. It is likely that the improved Young’s modulus was due to the higher Young’s modulus of the CNCs, compared with the multi-walled carbon nanotube (MWCNT) bundles. The helical structure of the CNCs also contributed to the improvement in the Young’s modulus. In the BP containing CNCs, the CNCs were anchored in the MWCNT matrix with superior entanglement, and this effect improved the Young’s modulus of the BP.

Organic catalyst has recently been identified as the potential substitution for expensive platinum electrocatalyst for fuel cell application. Numerous studies have shown that the nitrogen-containing carbon nanotubes (N-CNT) can be synthesized through spray pyrolysis or floating chemical vapor deposition (CVD) technique using various type of organometallic as precursors. This paper presents the method of synthesis and the initial findings of the growth of N-CNT directly on carbon paper using a modified CVD technique. In this research, nickel (II) phthalocyanines (Ni-Pc) as precursor was dissolved in ethanol solvent, stirred and sonicated to become homogenized. The solution was poured into a bubbler and heated up to allow the mixture to vaporize. Subsequently, the solution vapor was flowed into the tubical reactor maintained at 900°C. Carbon paper sputtered with nickel nanoparticles was used as the substrate. The synthesized sample was examined through Field Emission Scanning Electron Microscopy (FESEM), At...

For the paper industry, stiffness properties are an important parameter for producing more efficiently a fibrous material like paper. Some stiffness properties of paper webs can be obtained in a non‐contact fashion using two lasers. The authors have developed an automated laboratory laser‐ultrasonics instrument for paper, described here. The results of non‐contact laser generation and detection of ultrasound are also presented. The paper grades investigated were heavy grades like linerboard, as well as copy paper.

The mechanical and electrical properties of a bulk material made of single wall carbon nanotubes (SWNT) are, due to weak intermolecular interaction, several orders of magnitude lower than those of the individual molecules themselves. We studied the effect of gamma‐irradiation on SWNT paper in air and under vacuum. For samples irradiated in air, changes in Young modulus and electrical conductivity were observed with maximum value for a dose of 170 kGy. Under vacuum there was only a small effect of irradiation. Raman studies of irradiated samples showed defects formation. Same experiments done with graphite showed similar results. A likely explanation of the results is that cross‐links between nanotubes were induced by irradiation in air.

An important material property in the paper industry is the anisotropic stiffness distribution due to the fibrous microstructure of paper. Ultrasonic methods offer a means of determining the stiffness of sheets of paper from the anisotropic propagation characteristics of elastic Lamb waves along the machine direction (MD) and the cross direction (CD). Currently, piezoelectric ultrasonic methods are employed in the industry to measure the elastic polar diagram of paper through multiple contacting measurements made in all directions. This paper describes a new approach utilizing the INEEL Laser Ultrasonic Camera to provide a complete image of the elastic waves traveling in all directions in the plane of the paper sheet. This approach is based on optical dynamic holographic methods that record the out of plane ultrasonic motion over the entire paper surface simultaneously without scanning. The full-field imaging technique offers great potential for increasing the speed of the measurement and it ultimately pr...

On-line measurement of material properties is a goal of many manufactures for production improvement and quality control. In the paper industry, the elastic stiffness of the paper web needs to be accurately measured and controlled online. Currently, contact ultrasonic methods are employed to measure the elastic constants of paper offline. Piezoelectric transducers are placed in contact with the paper surface to generate and detect plate wave modes, known as Lamb wave modes, in the paper in both the machine and cross directions. Laser ultrasonics offers a new approach to making elastic wave measurements that does not require contacting the paper web. A pulsed laser generates ultrasound in the paper by delivering a high intensity short impulse to the paper through thermoelastic expansion. An optical interferometer is used to demodulate the small phase modulation that the elastic wave produces on a continuous probe laser beam. Difficulty in applying this approach to online measurements of rapidly moving pape...

Ligno-cellulosic biomass from sustainable sources has been used to produce light weight and high specific surface area (SSA) activated carbons (AC) for a multitude of applications; such as components in energy storage devices such as batteries and supercapacitors. While direct conversion from biomass has been studied heavily, such AC with relatively high surface area can be more effectively produced when leveraged as a co-product from a biorefinery. In this paper, we discuss the production of high specific surface area activated carbons from residual fiber (fiber remaining after extraction of C5-sugars) generated as part of a biorefinery. Our work showed that the AC produced from the residual fiber delivered an order of magnitude higher surface area than the one directly from corn pericarp fiber and soy hulls. These AC were evaluated as electrodes in electrical double layer capacitors for energy storage. These results, along with the benefits of using the residual fiber to produce AC, are highlighted in this paper.

The level consumption of Polyethylene Terephthalate (PET) as a packaging of colored beverage bottles occupies the fourth largest in the world. In Indonesia, PET consumption increased reaches 7% per year so that it can cause environmental impacts. This study aims to process the recycling PET waste by obtaining a simple potential process to remove the color from PET waste. The decolorized PET waste will be an alternative carbon source for Carbon Nanotube (CNT) synthesis. The colors of PET waste are blue and green bottles. The selected color removal agent is hydrogen peroxide (H2O2) because it is inexpensive reagent and has lower toxicity to environment. The colored PET waste and H2O2 will be heated in the oil bath system at temperature 110°C and pressure 1 atm. The result showed that color removal time for blue PET waste faster than the green PET waste, 72 and 115 minutes per 15 grams PET waste. The quality of color removal of blue PET waste is better than the green PET waste because it has a reflectance value closer to colorless PET waste, namely 80%. The CNT synthesis process from decolorized blue PET waste produce 8.58% yields. The average diameter of CNT crystals from its process is obtained at 37 nm. This shows that PET waste plastic which has been discolored can be used as a carbon source in CNT synthesis.

Batik industry in Indonesia frequently dispose liquid waste containing high level of toxic and carcinogenic dyes to the drainage without being treated. In accordance with it, plasma electrolysis has been proved as the efficient method to degrade dyes waste, yielding higher hydroxyl radicals than other methods. The experiment was conducted by generating plasma in circulated reactor using stainless steel cathode and tungsten anode with 2 cm depth immersed in 0.02 M Na2SO4 electrolyte solution added by 20 mg/L Fe2+ and 100 mg/L of Remazol Red initial concentration, with addition of varying air injection rate at maintained power. The results show that 1 L/min is the optimum air injection rate value to operate this reactor effectively at 450 W of optimum operating power so that it could lower the breakdown voltage, reduce energy consumption, produce more OH radicals and other reactive species, and elevate the degradation percentage. The experiment conducted in optimum operating condition provide result of 99.61% in degradation percentage for 60 minutes with final concentration of dye is 0.39 mg/L, 41.55 mg/L of COD, and 3177.16 kJ of energy consumption.

Water filter has been made to improve well water quality by using filtration concept in which activated carbon from cocoa rind waste and clay was used. The filter was made by varying the composition of cocoa rind waste and clay in activated carbon at the ratios of 85%:15%, 80%:20%, 75%:25%, 70%:30% and 65%:35%. The combustion temperature was varied at 200°C, 230°C, 260°C, 290°C and 320°C. Then it was molded by using mold and press conventional technique. The characterization results showed optimum composition was reached at 65%:35% ratios under 320°C combustion where the absorbance and porosity of water filter were at 86% and 52.38% respectively. Whereas density of 0.617 g/cm3 and 0.00514 MPa compressive strength were obtained from 85%:15% composition at 200°C combustion temperature. The performance test for the filter in purifying well water gave 3.2 NTU for turbidity, 7 TCU for color, 338 µS/cm conductivity, 6.7 pH level and Fe content of 1.0 mg/L. The analysis done showed that the water filtered has met the standard quality of clean water.

The paper focuses on the development of a low-cost biogas filtration system for alternating current generator to achieve higher efficiency in terms of power production. A raw biogas energy comprises of 57% combustible element and 43% non-combustible elements containing carbon dioxide (36%), water vapor (5%), hydrogen sulfide (0.5%), nitrogen (1%), oxygen (0 – 2%), and ammonia (0 – 1%). The filtration system composes of six stages: stage 1 is the water scrubber filter intended to remove the carbon dioxide and traces of hydrogen sulfide; stage 2 is the silica gel filter intended to reduce the water vapor; stage 3 is the iron sponge filter intended to remove the remaining hydrogen sulfide; stage 4 is the sodium hydroxide solution filter intended to remove the elemental sulfur formed during the interaction of the hydrogen sulfide and the iron sponge and for further removal of carbon dioxide; stage 5 is the silica gel filter intended to further eliminate the water vapor gained in stage 4; and, stage 6 is the activated carbon filter intended to remove the carbon dioxide. The filtration system was able to lower the non-combustible elements by 72% and thus, increasing the combustible element by 54.38%. The unfiltered biogas is capable of generating 16.3 kW while the filtered biogas is capable of generating 18.6 kW. The increased in methane concentration resulted to 14.11% increase in the power output. The outcome resulted to better engine performance in the generation of electricity.

Emulsions are dispersion systems, where one phase is dispersed in another phase in the presence of an emulsifying agent (surfactant). Emulsion fuel can reduce cylinder peak pressure from the combustion chamber compared to using neat diesel fuel. This research use a single-cylinder diesel engine, operates using water diesel emulsion with water percentage of 30% and 35% by volume and diesel fuel as a comparison. Diesel operates with a speed of 1500 rpm and engine load 1000-4000 watts at 500-watt intervals. The results of research at high load showed that fuel consumption of E30 and E35 increased by 15.5% and 16.6%, thermal efficiency increased by 21% and 35.8% (respectively). Whereas HC and CO emissions increase along with the increase in water percentage.Emulsions are dispersion systems, where one phase is dispersed in another phase in the presence of an emulsifying agent (surfactant). Emulsion fuel can reduce cylinder peak pressure from the combustion chamber compared to using neat diesel fuel. This research use a single-cylinder diesel engine, operates using water diesel emulsion with water percentage of 30% and 35% by volume and diesel fuel as a comparison. Diesel operates with a speed of 1500 rpm and engine load 1000-4000 watts at 500-watt intervals. The results of research at high load showed that fuel consumption of E30 and E35 increased by 15.5% and 16.6%, thermal efficiency increased by 21% and 35.8% (respectively). Whereas HC and CO emissions increase along with the increase in water percentage.

Ethanol-Diesel blended fuel is usually known as ‘E-Diesel’, ‘Diesohol’ or ‘Oxygenated Diesel’ that has been performed on the unmodified compression ignition engine. Three different proportions of 5%, 7.5% and 10% ethanol (by volume) are blended with diesel that being used as fuel. Biodiesel was added at the range of 5-10% into the blended fuels as emulsifier and balancing the overall fuel properties. Based on the properties test, it was found that the blended fuels have lower heating value, kinematic viscosity and density as the percentage of ethanol was increased. For the engine performance characteristics, no significant reduction in brake specific fuel consumption (BSFC) due to slight difference in heating values between diesel and blended fuels. The percentage deviation of brake thermal efficiency (BTE) for blended fuels from diesel were less than 4% showing the engine converted the chemical energy in fuels into mechanical energy almost the same efficiency. Whilst for emissions, the blended fuels reduced in oxides of nitrogen (NOX) at the range of 24.1-43.1% compared to diesel. As conclusion, the best blended fuel is E5 which contained 5% ethanol, 7.5% biodiesel and 87.5% diesel (D87.5B7.5E5) that contributed lower NOX emitted and performed better in term of BSFC and BTE.

Thin films of graphene oxide (or reduced graphene oxide) recently drawn a huge attention because of their several applications which are based on properties of graphene. The aim of the present paper is twofold: to find the straightforward, simple and cheap method for the preparation of thin film of graphene oxide and to study the effect of electron beam irradiation on the GO thin film. GO film was made by drop casting method from commercially procured aqueous solution of GO (concentration - 5 g/L). Electron beam irradiation were done in SEM obtain from MIRA II LMH from TESCAN. Irradiation of GO film was done at 25 keV electron beam energy. The authors have measured I-V characteristic of pristine as well as irradiated GO thin film in two probe configuration. Irradiation time were chosen 1 min, 33 min and 100 min which corresponds to 3×1011 e-/cm2, 1×1013 e-/cm2 and 3×1013 e-/cm2 fluence of electron beam. The samples were characterized using SEM and Raman methods. I-V spectra show that the resistance of fil...

In recent year, the Ordinary Portland Cement (OPC) concrete is vastly used as main binder in construction industry which lead to depletion of natural resources in order to manufacture large amount of OPC. Nevertheless, with the introduction of geopolymer as an alternative binder which is more environmental friendly due to less emission of carbon dioxide (CO2) and utilized waste materials can overcome the problems. Rice husk (RH) is an agricultural residue which can be found easily in large quantity due to production of paddy in Malaysia and it’s usually disposed in landfill. This paper investigated the effect of rice husk (RH) content on the strength development of fly ash based geopolymer mortar. The fly ash is replaced with RH by 0%, 5%, 10%, 15% and 20% where the sodium silicate and sodium hydroxide was used as alkaline activator. A total of 45 cubes were casted and their compressive strength, density and water absorption were evaluated at 1, 3, and 7 days. The result showed compressive strength decreased when the percentage of RH increased. At 5% replacement of RH, the maximum strength of 17.1MPa was recorded at day 7. The geopolymer has lowest rate of water absorption (1.69%) at 20% replacement of RH. The density of the sample can be classified as lightweight geopolymer concrete.

Diesel oil as an energy source is insufficient to meet the present-day energy demands and rapid industrial development. The goal of this work is to experimentally investigate the effects of using CDB (Cashew Nut Shell Oil diesel blends i.e. B20) mixture of 80% diesel by volume with 20% CNSO with different injection pressures (IP) of 200, 220 and 240 bar respectively. In the present scenario, CNSO is one of the superlative substitute sources which are comparably the cheapest non-edible sources in nature. The test was carried out with CDB in a 4-stroke, single cylinder diesel engine, at a rated power of 4.4 kW and constant speed of 1500 rpm. The effect of combustion analysis of test fuels at a net heat release rate, cylinder pressure, brake specific fuel consumption (BSFC), brake thermal efficiency (BTE) and cylinder temperature were observed by the performance tests. The experimental results revealed that BTE have improved whereas BSFC of CDB fuelled has been reduced, at 220 bar IP. It is also seen that there is a significant reduction in emissions of hydrocarbons, carbon monoxide, and smoke opacity with 220 bar IP, whereas carbon dioxide and nitrogen oxide shows increasing trends.

The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3− concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was about 6 times higher than that of our previous system. It was confirmed that the NO2−, O3, and H2O2 concentrations in the water were also increased by treating the water using the MSDS.The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3− concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was abo...

Geopolymer is an inorganic polymer composite developed by Joseph Davidovits in 1970s. Such material has potentials to replace Ordinary Portland Cement (OPC)-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in this study, red mud and rice husk ash were used as raw materials for geopolymeric production, which are aluminum industrial and agricultural wastes that need to be managed to reduce their negative impact to the environment. The red mud and rice husk ash were mixed with sodium silicate (water glass) solution to form geopolymer paste. The geopolymer paste was filled into 5-cm cube molds according to ASTM C109/C109M 99, and then cured at room temperature for 28 days. These products were then tested for compressive strength and volumetric weight. Results indicated that the material can be considered lightweight with a compressive strength at 28 days that are in the range of 6.8 to 15.5 MPa. Moreover, the geopolymer specimens were also tested for heat resistance at a temperature of 1000oC for 2 hours. Results suggest high heat resistance with an increase of compressive strength from 262% to 417% after exposed at high temperature.Geopolymer is an inorganic polymer composite developed by Joseph Davidovits in 1970s. Such material has potentials to replace Ordinary Portland Cement (OPC)-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in this study, red mud and rice husk ash were used as raw materials for geopolymeric production, which are aluminum industrial and agricultural wastes that need to be managed to reduce their negative impact to the environment. The red mud and rice husk ash were mixed with sodium silicate (water glass) solution to form geopolymer paste. The geopolymer paste was filled into 5-cm cube molds according to ASTM C109/C109M 99, and then cured at room temperature for 28 days. These products were then tested for compressive strength and volumetr...

Graphene oxide has many applications such as in electronic devices, as storage energy device, biosensor, biomedical application, water purification, coating technology, as a composite and paper like materials. Hummer’s method is one of the most common methods used in synthesizing graphene oxide. Graphene is different in size and structure because of oxidized layered of graphene oxide hence, the expanded interlayer structure of graphene oxide can be easily exfoliated by ultrasonication. We report on the preparation of exfoliated graphene oxide by using sonication method. Ultraviolet-visible spectrometer (UV-Vis) and Fourier-Transform Infrared Spectra Analyzer (FTIR) were used to characterize the exfoliated graphite oxide. Exfoliation of graphite oxide is conducted using water bath sonication. In order to confirm the chemical conformation and structure of the produced graphene oxide, FTIR and UV-Vis spectroscopy were utilized. Both peak of C=O and C-C bond are detected using UV-Vis and the results were conf...

Principle conditions for layer-by-layer synthesis of nanocomposite films incorporating graphene and metal oxides or hydroxides are formulated in the paper. As an example of this method the synthesis of nanocomposite containing graphene nanosheets and copper oxide (II) nanorods is described. This material was first synthesized in our study using amminecuprate (II) solution and water suspension of graphene. Analysis of the synthesized thin films by SEM, XRD and Raman spectroscopy have shown that the size of the graphene nanosheets in the films is about 5 µm and the size of the cupric oxide nanorods with monoclinic crystalline structure is approximately 10-12 by 150-200 nm. Some recommendations are given concerning potential applications of these layers in the electrodes of electrocatalysts and electrochemical sensors.

Geopolymer is an environmentally attractive Portland cement substitute, owing to its lower carbon footprint and its ability to consume various aluminosilicate waste materials as its precursors. This work describes the development of geopolymer formulation based on biomass-coal ash blends, which is predicted to be the prevalent type of waste when biomass-based thermal energy production becomes mainstream in Indonesia. The ash blends contain an ASTM Class F coal fly ash (FA), rice husk ash (RHA), and coconut shell ash (CSA). A mixture of Na2SiO3 and concentrated KOH is used as the activator solution. A preliminary experiment identified the appropriate activator/ash mass ratio to be 2.0, while the activator Na2SiO3/KOH ratio varies from 0.8 to 2.0 with increasing ash blend Si/Al ratio. Both non-blended FA and CSA are able to produce geopolymer mortars with 7-day compressive strength exceeding the Indonesian national SNI 15-2049-2004 standard minimum value of 2.0 MPa stipulated for Portland cement mortars. As...

Graphene flakes have been grown by chemical vapour deposition (CVD) method on Cu foils. The obtained graphene flakes have been characterized by optical microscopy, field emission scanning electron microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy. The graphene flakes grown on Cu foil comprise mainly single layer graphene and confirm that the nucleation for graphene growth starts very quickly. Moreover, KPFM has been found to be a valuable technique to differentiate between covered and uncovered portion of Cu foil by graphene flakes deposited for shorter duration. The results show that KPFM can be a very useful technique in understanding the mechanism of graphene growth.

An experimental study on co-pyrolysis of coal with biomass wastes to produce hybrid coal was conducted to investigate the effects of important process variables, namely biomass type (rice husk and sawdust), blend composition, and co-pyrolysis temperature on the quality of hybrid coal. The experiments were carried out using a vertical tubular furnace equipped with temperature controller to maintain the co-pyrolysis reactor at a given temperature. Nitrogen gas was introduced into the furnace to create an inert environment preventing the sample from burning. A known mass of solid sample consisting of manually granulated blend of coal and biomass with binder in spherical shape was contained in a basket made of stainless sieve. After a given residence time, the sample was taken from the furnace. The blend sample prior to experiment and the produced hybrid coal were then characterized for its proximate analysis, ultimate analysis and calorific value. Experimental findings suggested that by increasing co-pyrolys...

Depletion of petroleum and environmental problem have led to look for an alternative fuel sources In many ways, biomass is a potential renewable source. Among the many forms of biomass, oil palm empty fruit bunch (EFB) is a very attractive feedstock due to its abudance, low price and non-competitiveness with the food chain. EFB can be converted bio-oil by pyrolysis process. but this product can not be used directly as a transportation fuel, so it needs upgrading bio-oil through a catalytic cracking process. The catalyst plays an important role in the catalytic cracking process. The objective of this research is to study the effect of Ni concentrations (1,3,5 and 7 wt.%) on the characteristics of the catalyst Ni / Silica-Alumina and the performance test for the catalytic cracking of bio-oil. Preparation of the catalyst Ni / Silica-Alumina was done by impregnation at 80°C for 3 hours, then done to calcination and reduction at 500°C for 2 hours. The performance test was conducted on catalytic cracking temper...

In this work, graphene was exfoliated by introducing the constant Galvano Static Current (GSC) at the range of 300-600mA with the incremental of 100mA. The Graphene produced through this exfoliation technique was also investigated through optical characterization using Field Emission Scanning Electron Microscope (FESEM), Ultraviolet Visible (UV-vis) spectroscopy and Raman spectroscopy to comprehend the quality behavior. To further understand the graphene characteristic, we applied the produced graphene on top of fabricated interdigitated electrode (IDE) device to investigate the electrical reaction.

Traditional additive-free graphene bulk materials based on mono- three dimensional(3D) graphene networks type are fragile in most cases, which is unfavorable for their potential applications. Here we present compressible graphene foams (CGF) with superior properties endowed by the hierarchical porous structure, which taking graphene sheets as an inorganic embedding material and polyurethane sponge (PUS) as a polymer open-framework. The preparation process utilized a dip-coating method associated with directional freezing followed by lyophilization. The as-synthesized CGF not only possess a combination of ultralow density and excellent electrical conductivity, but it also can withstand large strains (>99%) without permanent deformation or fracture. We believe that these sponge/graphene embeddable multifunctional nanocomposites will expand practical applications of graphene monolith in the future.

We report a simple technique for synthesis of reduced graphene oxide (rGO). In this technique ferrous sulfate (FeSO4) has been used to reduce the oxygen functional groups from the graphene oxide. The prepared rGOs have been characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), UV-Vis and Raman spectroscopy. The TEM and HRTEM reveal that the prepared rGOs are mostly double layers. This technique can be adopted to prepare rGO in large scale.

Graphene oxide (GO) and reduced graphene oxide (RGO) are known to have superior properties for various applications. This work compares the properties of GO and RGO with graphite. GO was prepared by using Improved Hummer’s method whereas the produced GO was subjected to chemical reduction with the use of hydrazine hydrate. Graphite, GO and RGO had different morphologies, quality, functionalized groups, UV-Vis absorption peaks and crystallinity. With the removal of oxygen-containing functional group during reduction for RGO, the quality of samples was decreased due to higher intensity of D band than G band was seen in Raman results. In addition, platelet-like surface can be observed on the surface of graphite as compared to GO and RGO where wrinkled and layered flakes, and crumpled thin sheets were observed on GO and RGO surface respectively. Fourier Transform Infra-Red (FTIR) analysis showed the presence of abundant oxygen-containing functional groups in GO as compared to RGO and graphite. The characteris...

We compared thermal behavior and other properties of graphite oxide, thermally reduced graphene and chemically reduced graphene. Graphite was oxidized according to the Hofmann method using potassium chlorate as oxidizing agent in strongly acidic environment. In the next step, the formed graphite oxide was chemically or thermally reduced yielding graphene. The mechanism of thermal reduction was studied using STA-MS. Graphite oxide and both thermally and chemically reduced graphenes were analysed by SEM, EDS, elemental combustion analysis, XPS, Raman spectroscopy, XRD and BET. These findings will help for the large scale production of graphene with appropriate chemical composition.

In this study electrocoagulation method is used to treat slaughterhouse wastewaters. The aim of this study is to determine the efficiency of electrocoagulation method for the removal of colour, turbidity, oil and grease of slaughterhouse wastewaters. The factors of electrode types, and voltage applied during treatment are the study parameters. The types of electrode used are Aluminium (Al) grade 6082 and Iron (Fe) grade 1050. Meanwhile, the ranges of voltage applied are 2, 4, 6, 8 volts at a time interval of 10, 20 and 30 minutes respectively. The effect of these factors on the removal of fat oil and grease (FOG), colour and turbidity are analyzed. The results show maximum removal of FOG, colour and turbidity are recorded using Fe electrode at 8 V of applied voltage with 30 minutes of treatment time. The increase in treatment time of the cell will also increase the amount of hydrogen bubbles at the cathode which results in a greater upwards flux and a faster removal of FOG,, turbidity and colour. The removal of FOG, colour and turbidity are 98%, 92% and 91 % respectively. Meanwhile, by using Al electrodes in the same condition, the removal of FOG, colour and turbidity are 91%, 85% and 87 % respectively. Whereas by using Fe-Al as electrodes pairs, the removal of FOG, colour and turbidity are found to be at 90%, 87% and 76 % respectively. In this case, the Fe-Fe pair electrodes have been proven to provide better performance for FOG, colour and turbidity removals of slaughterhouse wastewaters. Therefore, it is feasible to be considered as an alternative method for wastewater treatment.In this study electrocoagulation method is used to treat slaughterhouse wastewaters. The aim of this study is to determine the efficiency of electrocoagulation method for the removal of colour, turbidity, oil and grease of slaughterhouse wastewaters. The factors of electrode types, and voltage applied during treatment are the study parameters. The types of electrode used are Aluminium (Al) grade 6082 and Iron (Fe) grade 1050. Meanwhile, the ranges of voltage applied are 2, 4, 6, 8 volts at a time interval of 10, 20 and 30 minutes respectively. The effect of these factors on the removal of fat oil and grease (FOG), colour and turbidity are analyzed. The results show maximum removal of FOG, colour and turbidity are recorded using Fe electrode at 8 V of applied voltage with 30 minutes of treatment time. The increase in treatment time of the cell will also increase the amount of hydrogen bubbles at the cathode which results in a greater upwards flux and a faster removal of FOG,, turbidity and colour. The remo...

In this work, we emphasize on the surface property modification involved during the strong interfacial adhesion of graphene oxide (GO) nanosheets with poly vinyl alcohol (PVA) matrix. Raman, x-ray diffraction spectrum and scanning Kelvin probe microscopic measurement were done to analyze the effect of graphene oxide on surface property of poly vinyl alcohol.

This study investigates the treatability of composite adsorbent made from waste materials and minerals which is widely available in Malaysia. The composite adsorbent was prepared based on wet attrition method which focuses on the determination of optimum dosage of each of raw materials amount by conventional design of experiment work. Zeolite, activated carbon, rice husk and limestone were ground to obtained particle size of 150 µm. 45.94% zeolite, 15.31% limestone, 4.38% activated carbon, 4.38% rice husk carbon and 30% of ordinary Portland cement (OPC). The mixture was mixed together under pre-determined mixing time. About 60% (by weight) of water was added and the mixture paste was allowed to harden for 24 hours and then submersed in water for three days for curing. Batch experimental study was performed on synthetic dissolving a known amount of solid crystal phenol with distilled water into the volumetric flasks. From the batch experimental study, it was revealed that the optimum shaking speed for remo...

Vacuum filtration method was used in order to fabricate a homogeneous and uniform thin film of multi-layer graphene oxide on plastic substrate. This self-regulating technique allows the number of graphene oxide layer to be controlled thus controlling the film thickness by simply varying either the concentration of the graphene oxide in the suspension or the filtration volume. Measurement of the sheet resistance as a function of graphene oxide concentration in solution shows the percolation behavior of multi-layer films. The device was then exposed in nitrogen dioxide (NO2) environment at room temperature and 200 °C, under atmospheric pressure. Results demonstrate that the graphene oxide film shows good sensitivity and excellent recovery time using plastic substrate.

The efficient reduction of graphene oxide (rGO) was performed using Sodium Borohydride (NaBH4). These reduction approaches remove the majority of the oxygen-containing functional groups at the basal plane and surface of graphene oxide sheets. Structural and physiochemical properties of the GO were investigated with help of Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), and Ultraviolet-Visible-Near infrared (UV-Vis-NIR). The effects of the chemical reduction on a GO surface were analyzed using a Semiconductor Parameter Analyzer (SPA) in order to obtain the electrical resistance measurement. It was found that the resistance of reduced graphene oxide was greatly reduced when compared to the condition of before reduction process. Then, the formation of uniform thin film of rGO sheets was produced using vacuum filtration method in order to fabricate a gas sensor. In this project, plastic was used as a substrate. The sensor was then being e...

In this work, Graphene nanosheets were prepared using probe assisted ultrasonication technique. Field emission scanning electron microscopy (FESEM) and high resolution scanning electron microscopy (HRTEM) analysis confirmed the plane sheet like morphology of graphene. As of known, graphene is a two dimensional and nanometer thick layered structures, it is found to be phenomenal in its electrochemical characteristics and was found to be electrochemically active. It is highly stable for large number of charge-discharge cycles, and being a carbon derived nanostructure, it stores charges through capacitive mechanism. To wonder, graphene prepared through our method stores charges both physically and chemically as Capacitive-Nernstian mechanism and was evident through cyclic voltammetry (CV) measurements. These combined phenomena can make graphene nanostructures as a potential candidate in various charge storage devices.

A green method and eco-friendly solution were used to chemically reduce graphene oxide (GO) to graphene using green reductant. In this study, graphene oxide (GO) were prepared by using Tours method. Then, reduced graphene oxides (rGO) were prepared by using three typical reduction agents: L-ascorbic acid (L-AA), formamidinesulfinic acid (FAS) and sodium sulfite (Na2SO3). The reduced materials were characterized by Fourier transform infrared spectroscopy (FTIR), Thermo gravimetric analysis (TGA) and X-ray diffraction (XRD). Graphene based organic thin film transistor (G-OTFT) was prepared by a spin coating and thermal evaporation technique. The electrical characterization of G-OTFT was analyzed by using semiconductor parameter analyzer (SPA). The G-OTFT devices show p-type semiconducting behaviour. This article focuses on the synthesis and reduction of graphene oxide using three different reductants in order to maximise its electrical conductivity. The rGO product demonstrated a good electrical conductivit...

Natural flake Graphite was used as the starting material for the graphene synthesis. In the first step flake graphite was treated with oxidizing agents under vigorous conditions to obtain graphite oxide. Layered graphite oxide decorated with oxygen has large inter-layer distance leading easy exfoliation into single sheets by ultrasonication giving graphene oxide. In the last step exfoliated graphene oxide sheets were reduced slowly with the help of reducing agent to obtain fine powder which is labeled as reduced graphene oxide (rGO). This rGO was further characterized by X-Ray Diffraction (XRD), Scanning Tunneling Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy techniques. XRD pattern shows peaks corresponding to (002) graphitic lattice planes indicating the formation of network of sp2 like carbon structure. SEM images show the ultrathin, wrinkled, paper-like morphology of graphene sheets. IR study shows that the graphite has been oxidized to graphite oxide with the presence of various absorption bands confirming the presence of oxidizing groups. The FTIR spectrum of rGO shows no sharp peaks confirming the efficient reduction of rGO. The Raman spectrum shows disorder in the graphene sheets.

Graphene is a 2D form of carbon. Due to its wonderful physical and chemical properties has attracted wide interest in recent years. Graphene majorly made by two completely different approches i.e. top-down and bottom up. The top-down approach depends on exfoliation of carbon to provide graphene. Liquid phase exfoliation is more classified in to primarily two categories one is surfactant free and another is surfactant aided Liquid part exfoliation. In this paper we have reportable the liquid phase exfoliation of surfactant aided graphene via probe tip sonication followed by centrifugation. The yield of graphene obtained has been exaggerated and it is easy technique to provide films and graphene composites for photovoltaic applications.

Charge transfer techniques have been extensively used as knobs to tune electronic properties of two- dimensional systems, such as, for the modulation of conductivity \ mobility of single layer graphene and for opening the bandgap in bilayer graphene. The charge injected into the graphene layer shifts the Fermi level away from the minimum density of states point (Dirac point). In this work, we study charge transfer in rotated double-layer graphene achieved by the use of organic dopant, Tetracyanoquinodimethane. Naturally occurring bilayer graphene has a well-defined A-B stacking whereas in rotated double-layer the two graphene layers are randomly stacked with different rotational angles. This rotation is expected to significantly alter the interlayer interaction. Double-layer samples are prepared using layer-by-layer assembly of chemical vapor deposited single-layer graphene and they are identified by characteristic resonance in the Raman spectrum. The charge transfer and distribution of charges between th...

A novel method of creating new lightweight aluminum-metallic composite materials in halide melts at temperatures of 973–1073 К in air atmosphere is proposed. The method for synthesizing aluminum-based metallic composite materials containing up to 2 wt. % graphene sheets uniformly distributed in a metal matrix is entirely new, having no analogies in current science and practice. The synthesis of graphene nanosheets in a metal matrix is a one-step simultaneous process taking place directly in molten aluminum in alkali halide melt without the necessity of a separate stage of synthesis and introduction of graphene. This has the potential to facilitate the inexpensive synthesis of aluminum-graphene composites with a high concentration of graphene. Aluminum-graphene composites formed according to this method are characterized by a high uniformity of graphene films with linear dimensions from 100 nm to 50 µm and a thickness from 1 nm to 3 nm in the metal bulk. No aluminum carbide forms under synthesis; aluminum-graphene and aluminum-graphite composites are resistant to corrosion in a NaCl solution. The hardness, strength and ductility of aluminum-graphene composites are at least 2–3 times as high as the initial aluminum material, proportional to the concentration of graphene.

Graphene Oxide (GO) is analogous to graphene, but presence of many functional groups makes its physical and chemical properties essentially different from those of graphene. GO is found to be a promising material for low cost fabrication of highly versatile and environment friendly gas sensors. Selectivity, reversibility and sensitivity of GO based gas sensor have been improved by hybridization with Zinc Oxide nanoparticles. The device is fabricated by spin coating of deionized water dispersed GO flakes (synthesized using traditional hummer’s method) doped with Zinc Oxide on standard glass substrate. Since GO is an insulator and functional groups on GO nanosheets play vital role in adsorbing gas molecules, it is being used as an adsorber. Additionally, on being exposed to certain gases the electric and optical characteristics of GO material exhibit an alteration in behavior. For the conductivity, we use Zinc Oxide, as it displays a high sensitivity towards conduction. The effects of the compositions, structural defects and morphologies of graphene based sensing layers and the configurations of sensing devices on the performances of gas sensors were investigated by Raman Spectroscopy, X-ray diffraction(XRD) and Keithley Sourcemeter.

(1-x)Cobalt ferrite-(x)reduced graphene oxidenanocomposites with x=0, 0.1, 0.2 and 0.3 were prepared by the ultrasonic method. The crystal symmetry modification due to reduced graphene oxide and cobalt ferrite interaction has been studied by employing the X-ray diffraction technique. Morphology of the samples was studied by the Field emission scanning electron microscopy (FE-SEM). Study on electrical properties of the cobalt ferrite-reduced graphene oxide nanocomposites explores the possible application of these composites as anode material. Impedance decreases with an increase in frequency as well as temperature, which supports an increase in ac electrical conductivity. The modified Debye relaxation model can explain the behavior of impedance in cobalt ferrite-reduced graphene oxide nanocomposites.