Search

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.

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 purpose of this paper is to study the Lean-TRIZ initiative within the context of service sector organizations. In addition, article has the objective to determine the Readiness Factors (RF) for the successful implementation of Lean- TRIZ in service sector organization. The research has utilized secondary data to justify the need for RF. Data from various indexed papers and conference papers were studied. The data thus obtained was coupled with the vast experience and the expertise of the authors in Lean implementation in service sector organization. The papers present RF which are essential for the sustainability of Lean-TRIZ in a service sector organization and provides a framework for the successful implementation. This is a theatrical paper based on the author’s vast experience in service sector organization and existing literature. Lean-TRIZ is still in embryonic stage with most of the academic literature only in conferences and there is a serious dearth in literature. Future researchers can focus on empirical studies in specific service sector organizations.

Nowadays, the high amount of waste generated by the world population represents a major environmental problem. Landfills still represent one of the main endpoints of the solid wastes disposal in most of the countries. The major problem associated with this is the landfill leachate production. Leachate treatment using microalgae has been reported in numerous studies and it is a very promising method. A key challenge is the sensitivity of microalgae to high contaminants in landfill leachate. This paper underlines the landfill leachate treatment using Chlorella vulgaris sp. with pre-treated landfill leachate by physico-chemical treatment. Current research is to explore a dual purpose method to treat the leachate by incorporating Chlorella vulgaris sp. culturing in 100% pre-treated landfill leachate. During pre-treatment, the leachate samples were undergone coagulation process by using aluminium ammonium sulphate 12-hydrate followed by modified filtration system. The chemical analysis such as Total Solids (TS), turbidity, pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Organic Carbon (TOC), and heavy metal contents were analysed for landfill leachate samples before the treatment, after physico-chemical treatment, and after the combined physico-chemical-biological treatment using Chlorella vulgaris. The combined coagulation, filtration and microalgae treatments achieved removal efficiencies of more than 94% on turbidity, COD, BOD, TOC, and heavy metals. Effective contaminants removal efficiencies have been attained through the pre-treatment by coagulation and filtration. Microalgae managed to polish the pre-treated leachate to achieve the standard discharge limit according to DOE of Malaysia government. The lipids with broad carbon range of (C-21 to C-36) were identified in Chlorella vulgaris. The paper proves that the deteriorative impact of landfill leachate can be reduced successfully with combined treatment approaches.Nowadays, the high amount of waste generated by the world population represents a major environmental problem. Landfills still represent one of the main endpoints of the solid wastes disposal in most of the countries. The major problem associated with this is the landfill leachate production. Leachate treatment using microalgae has been reported in numerous studies and it is a very promising method. A key challenge is the sensitivity of microalgae to high contaminants in landfill leachate. This paper underlines the landfill leachate treatment using Chlorella vulgaris sp. with pre-treated landfill leachate by physico-chemical treatment. Current research is to explore a dual purpose method to treat the leachate by incorporating Chlorella vulgaris sp. culturing in 100% pre-treated landfill leachate. During pre-treatment, the leachate samples were undergone coagulation process by using aluminium ammonium sulphate 12-hydrate followed by modified filtration system. The chemical analysis such as Total Solids (TS...

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 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.

Water treatment is the process to make the water reusable to consumers. There are several process to treat water such as chlorination, sedimentation and filtration. Water filtration is known to separate substance or object in contaminated water. Method of filtration is vary depending on the location of the targeted material whether it is dissolved in the suspended as a solid or fluid. This paper present a preliminary study to constructing a low-cost of water filter by using materials namely coarse aggregates, sand, activated carbon in additional of loofah and coconut fiber. The result was measured by analyzing the water parameter such as, Biochemical Oxygen Demand (BOD), Dissolve Oxygen (DO), turbidity, and colour. The result of raw water and filtered water are characterized according to the National Water Quality Standard (NWQS) for Malaysia. The final results from laboratory experiment showed a good improvement of water parameter during the application of coconut and loofah fiber in water filtration. The BOD5 result for coconut and loofah fiber model show significant improvement from class IV to class I and III.

Scarcity in fuel from fossil fuel has led to exploration of potential substitutes from renewable sources. Biodiesel as one of renewable energy sources is identified as cleaner alternative to petroleum fuel. This paper reports on the study of potassium carbonate, K2CO3 sourced from pineapple and orange peels as heterogeneous catalyst for biodiesel production. K2CO3 was produced by drying of fruit peel prior to calcination at temperature ranged from 700°C to 1000°C for 2 to 4 hours. To determine the physicochemical properties of the resulting ash, Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM) analysis were employed for the characterization of the solid. Through FTIR analysis, the presence of carbonate was confirmed while SEM analysis revealed the morphological properties of the catalyst. Biodiesel with highest yield of 95.6% was produced at 60°C, 2.75 wt% of catalyst and 12:1 molar ratio of methanol to oil.

The rapid dewatering process of wastewater sludge was studied. The effects of two different thickening methods on subsequent conditioning and pressing were compared: gravity thickening and mechanical concentration. The study also investigated the optimal type and the concentration of flocculant added by sludge concentration, which was 0.2%. In terms of mechanical concentration method, under the same formulation of conditioner, the addition of Polyacrylamide(PAM) could significantly promote the dewatering process. Compared with the gravitational sedimentation and the sludge without chemical concentration, the filtration rate and dry-base treatment efficiency of the sludge during pressing were obviously improved, and the moisture content of the sludge cake was reduced.

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.

In recent years, many researches have been performed to find suitable alternative fuels to petroleum products. In the present investigation, an experimental work has been carried out to analyze the performance and emissions characteristics of a single cylinder compression ignition DI engine fuelled with the blends of biodiesel at the different engine speed. The performance parameters evaluated were torque, brake power (BP), brake mean effective pressure (BMEP) and the emissions such as carbon monoxide (CO), carbon dioxide (CO2) and unburned hydrocarbon (UHC). The results of experimental investigation with biodiesel blends with diesel are compared with that of diesel. The performance parameter in terms of torque and BMEP are 12.5 % and 9% less for B5 and B10 than diesel respectively. BP for diesel was higher about 6 % compared to biodiesel blends. The results indicated that the UHC, CO and CO2 emissions are slightly less than diesel; UHC emissions were also observed to be 4% less for B5 and B10 compared to diesel, CO emissions were also observed to be 5% less for B5 and B10 compared to diesel and CO2 emissions were also observed to be 1% less for B5 and B10 compared to diesel. In a nutshell, performance characteristics for biodiesel were lower compared to diesel which not much significant difference, while emission characteristics for biodiesel blend were improved compared to diesel.

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.

Conventional media/sand filtration has been the mainstream water treatment process for most municipal water treatment plants in Malaysia. Filtrate qualities of conventional media/sand filtration are very much dependent on the coagulation-flocculation process prior to filtration and might be as high as 5 NTU. However, the demands for better quality of drinking water through public piped-water supply systems are growing. Polymeric ultrafiltration (UF) hollow fibre membrane made from modified polyethersulfone (PES) material is highly hydrophilic with high tensile strength and produces excellent quality filtrate of below 0.3 NTU in turbidity. This advanced membrane filtration material is also chemical resistance which allows a typical lifespan of 5 years. Comparisons between the conventional media/sand filtration and PES-based UF systems are carried out in this paper. UF has been considered as the emerging technology in municipal drinking water treatment plants due to its consistency in producing high quality filtrates even without the coagulation-flocculation process. The decreasing cost of PES-based membrane due to mass production and competitive pricing by manufacturers has made the UF technology affordable for industrial-scale water treatment plants.

Batik industry in Indonesia is growing very rapidly. This is of course accompanied by the increasing volume of waste generated, especially liquid waste. Liquid waste generated in the process of coloring, washing, or in the finishing process, if not handled intensively will cause environmental imbalances. The purpose of this research is to provide one alternative solution to treat batik liquid waste, especially in overcoming problems about COD and TSS levels. Bed layer and electrolysis combination techniques can be used to overcome the problem of batik waste. This technique uses parameters such as bed layer variation, layers, pH, electrolysis time, and voltage. The dependent variables analyzed in this study were the percentage decrease of Chemical Oxygen Demand (COD) and Total Solid Solution (TSS). Based on this research, it is found that the arrangement of bed layer combination with effective electrodegradation in lowering COD and TSS in batik liquid waste is charcoal, gravel, sand, rice husk ash, coconut fiber. The treatment was continued with electrolysis and the resulting efficiency of COD and TSS decrease were 60% and 85%

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.

Alum sludge needs to be managed properly to ensure its adverse potential impact to environment is mitigated due to its content of pathogen and metal. Usually, alum sludge will be dumped to the landfill for dewatering and become sludge cake due to inadequate facility to treat it. Furthermore, alum sludge treatment involves high cost and handling problem because of its water content and offensive odour. In this study, performance and evaluation of alum sludge ash (ASA) as a brick material was investigated. The alum sludge which was collected was fired to become ash. Ash characteristic (chemical content and mass losses) were investigated by means of Toxicity Characteristics Leaching Procedures (TCLP) and thermogravimetric analysis (TGA). The physical (water absorption and compressive strength) and chemical (leaching) properties mixture of Portland cement with the different weight percentage of alum sludge ash (0% - 40% by mass). TGA analysis showed that 95% of ASA residue remained at temperature 1000°C and the heavy metal contents in the leachate are below acceptable threshold limits. Increasing the ASA contents results in decreased compressive strength and increased water absorption. The result also showed that the mixture 30% of ASA by mass with Portland cement is at optimum condition as a brick material which is comply the standard of bricks.

Cotton is an inflammable substance that can be ignited by a weak ignition source. Since, cotton fiber is typically removed from cottonseed, compressed into bales and stored in the warehouse for extended periods of time, the moisture content is a very important characteristic of cotton. In this study, the effect of moisture content on cotton smoldering combustion was studied experimentally by characterizing cotton samples with different moisture contents. The results showed that the higher moisture content of cotton delayed the smoldering combustion process of cotton and prolonged the duration of high temperature of cotton smoldering. And we could find that when the moisture content is higher than 10%, the characteristics of smoldering change obviously.

The presence of lead heavy metals in waters can cause negative impacts on the environment. One way to reduce lead metal content is by adsorption process using waste of banana leaf. Adsorption of lead metal using banana leaf waste has been successfully done. This study aims to determine the optimum contact time so as to produce the greatest adsorption power to lead metal in banana leaf waste, and determine the adsorption kinetics. Determination of functional groups was performed by using infrared spectroscopy while the determination of lead content using atomic absorption spectroscopy. The adsorption process is done by batch system that is soaking bio sorbent in solution containing lead. The immersion times were varied at 0, 30, 60, and 120 minutes. The adsorption process is carried out by mixing 25 mL of Pb(NO3)2 solution with 0.125 gram of activated banana leaf waste. Determination of amount of lead metal adsorbed by banana leaf waste done by calculating the difference of initial metal concentration with concentration in filtrate. Based on result of research known that optimum adsorption time from waste of activated banana leaf is for 30 minutes. The adsorption capacity of activated banana leaf waste in the time was 35.714%. Adsorption kinetics of lead at banana leaf follows kinetic model of pseudo two Ho with the value of R2 0.924 and the value of k is 13.305 minutes−1.

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.

Sweet orange peel (Citrus sinensis) is part of orange plant that contains essential oils. Generally, taking essential oil from orange peel is still using hydrodistillation and steam-hydrodistillation method which still needs solvent and takes a long time to produce high quality essential oil. Therefore, the objectives of this experiment are to study the process of orange peel’s essential oil extraction using Solvent Free Microwave Extraction (SFME) and to study the operating condition that effect an optimum yield and quality of the essential oil. In this experiment, extraction process with SFME method goes for 60 minutes at atmospheric pressure. Variables for SFME are: variation of orange peel condition (fresh and dry), ratio orange peel mass to distiller volume (0,1; 0,2; 0,3; 0,4 g/mL), orange peel size (±0,5; ±2; ±3,5 cm width), and microwave power (100, 264, 400 Watt). Moisture content of fresh peel is 71,4% and for dry peel is 17,37% which is obtained by sun drying. The result of this experiment will...

The technological development of concrete demands innovation regarding the alternative material as a part of the effort in improving quality and minimizing reliance on currently used raw materials such as bottom ash of palm oil. Bottom ash known as domestic waste stemming from palm oil cultivation in East Kalimantan contains silica. Like cement in texture and size, bottom ash can be mixed with concrete in which the silica in concrete could help increase the compressive strength of concrete. This research was conducted by comparing between normal concrete and concrete containing bottom ash as which the materials were apart of cement replacement. The bottom ash used in this research had to pass sieve size (#200). The composition tested in this research involved ratio between cement and bottom ash with the following percentages: 100%: 0%, 90%: 10%, 85%: 15% and 80%: 20%. Planned to be within the same amount of compressive strength (fc 25 MPa), the compressive strength of concrete was tested at the age of 7, ...

In this study has been the treatment of batik waste using distillation method. This study aims to the treatment of batik waste using distillation method. Batik is a world heritage that has an impact on economic improvement and environmental damage. Batik waste is a hazardous and toxic waste material. Batik waste in this research has been taken from Batik Industry in Yogyakarta, Indonesia. Batik waste of 5 L is included in the distillation apparatus, then the distillation run for 4 hours. The distillation product of solids and liquids is collected and analyzed. The solid produced at the distillation boiler was analyzed by FTIR. The distillation liquid was analyzed ammonia and COD concentration using UV-Vis Spectrophotometer. The result of the analysis showed that based on FTIR spectra obtained by dye with high purity. The analysis results shown are of ammonia, COD and pH were 0.652 mg/L, 238.31 mg/L, and 7.306, respectively. The compounds produced by boiler are the azo dye based on the spectrum at wave numbers 1554.07 cm−1. The conclusion of this research is that the distillation method is very suitable for the treatment of the batik waste at small batik industry. Advantages of distillation techniques that can be obtained two products are water and dye that can be used in batik industry.

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...

As one of the solid waste generated by palm oil plantations, Oil Palm Fronds have the potential to be further processed into useful products since the presence of cellulose, hemicellulose and lignin. Hence, the objective of this study was to utilize oil palm fronds in producing oxalic acid through oxidation process using. To achieve the objective, this study assessed conversion of cellulose, yield and quality of oxalic acid produced. Two stages are carried out, namely oxidation and crystallization. Assays on raw materials revealed the cellulose content of 29.2 percent. The largest yield of oxalic acid was 43.31 percent, the highest conversion of cellulose was 58.86 percent. FTIR and melting point analysis were employed in this study. These analyses indicated that the functional groups have reached the standard of oxalic acid with a melting point of 102.1 °C, which showed that the oxalic acid obtained was oxalic acid dehydrate.

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...

Iron and Manganese was examined from riverbank filtration (RBF) and river water in Sungai Kerian, Lubok Buntar, Serdang Kedah. Water from the RBF was influenced by geochemical and hydro chemical processes in the aquifer that made concentrations of iron (Fe), and manganese (Mn) high, and exceeded the standard values set by the Malaysia Ministry of Health. Therefore, in order to overcome the problem, the artificial barrier was proposed to improve the performance of the RBF. In this study, the capability and performance of granular activated carbon, zeolite and sand were investigated in this research. The effects of dosage, shaking speed, pH and contact time on removal of iron and manganese were studied to determine the best performance. For the removal of iron using granular activated carbon (GAC) and zeolite, the optimum contact time was at 2 hours with 200rpm shaking speed with 5g and 10g at pH 5 with percentage removal of iron was 87.81% and 83.20% respectively. The removal of manganese and zeolite arose sharply in 75 minutes with 90.21% removal, with 100rpm shaking speed. The GAC gave the best performance with 99.39% removal of manganese. The highest removal of manganese was achieved when the adsorbent dosage increased to 10g with shaking speed of 200rpm.

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...

Loss of expensive mud could lead to major financial problem in executing a drilling project and is one of the biggest problems that need to be tackled during drilling. Synthetic Based Mud (SBM) is the most stable state of the art drilling mud used in current drilling technologies. However, the problem with lost circulation is still inevitable. The focus of this project is to develop a new potential waste material from banana peel in order to combat lost circulation in SBM. Standard industrial Lost Circulation Material (LCM) is used to compare the performance of banana peel as LCM in SBM. The effects of different sizing of banana peels (600 micron, 300 micron and 100 micron) were studied on the rheological and filtration properties of SBM and the bridging performance of banana peel as LCM additive. The tests were conducted using viscometer, HTHP filter press and sand bed tester. Thermal analysis of banana peel was also studied using TGA. According to the results obtained, 300 and 100 micron size of banana peel LCM exhibited an improved bridging performance by 65% as compared to industrial LCM. However, banana peel LCM with the size of 600 micron failed to act as LCM due to the total invasion of mud into the sand bed.

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...

The fabrication and characterization on reduced graphene oxide field effect transistor (RGO-FET) were demonstrated using a spray deposition method for biological sensing device purpose. A spray method is a fast, low-cost and simple technique to deposit graphene and the most promising technology due to ideal coating on variety of substrates and high production speed. The fabrication method was demonstrated for developing a label free aptamer reduced graphene oxide field effect transistor biosensor. Reduced graphene oxide (RGO) was obtained by heating on hot plate fixed at various temperatures of 100, 200 and 300°C, respectively. The surface morphology of RGO were examined via atomic force microscopy to observed the temperature effect of produced RGO. The electrical measurement verify the performance of electrical conducting RGO-FET at temperature 300°C is better as compared to other temperature due to the removal of oxygen groups in GO. Thus, reduced graphene oxide was a promising material for biosensor application.

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...