Environmental Engineering
M. Samimi
Abstract
BACKGROUND AND OBJECTIVES: Industrial wastewater usually contains metal ions which are hazardous to human and aquatic organisms. Nowadays, the application of inexpensive biomaterials in adsorptive removal of metal ions, such as plant biomass, has been widely considered. In this study, the efficiency ...
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BACKGROUND AND OBJECTIVES: Industrial wastewater usually contains metal ions which are hazardous to human and aquatic organisms. Nowadays, the application of inexpensive biomaterials in adsorptive removal of metal ions, such as plant biomass, has been widely considered. In this study, the efficiency of Eucalyptus globulus fruit biomass for biological adsorption of cadmium ions from aquatic environments has been evaluated.METHODS: After drying, the collected biosorbent was ground and powdered. The dried biomass, after screening with particle size of less than 45 micrometers, was used in all experiments. The effects of operating factors, such as biosorbent to cadmium ratio, pH value of the solution and residence time of biomass and metal, on the amount of analyte adsorption were evaluated by response surface methodology. The optimum conditions for maximum metal uptake by Eucalyptus globulus fruit biomass were also evaluated using the Box-Behnken Design model. Kinetic studies were statistically described to investigate the metal adsorption process.FINDINGS: Validation experiments showed the accuracy of the model proposed for determining the optimum conditions for the cadmium biosorption process. Based on the experimental data, the values of coefficient of determination, adjusted coefficient and predicted coefficient used in the model were determined as 0.9948, 0.9855 and 0.9245, respectively. Using the model, the maximum cadmium ion adsorption by biomass was obtained at 93.65 percent, biosorbent-to-metal ratio of 9:1, pH value of 6, and contact time of 80 minutes.CONCLUSION: In the present study, the Eucalyptus globulus fruit biomass, under optimal operating conditions, proved to be an efficient sorbent for cadmium uptake from aqueous environments. The results from the experimental data of the adsorption studies were consistent with pseudo-second-order kinetics (maximum capacity of 128.2 milligram per gram), indicating that the chemical adsorption of cadmium on the used biomass occurring in monolayers.
Environmental Engineering
W. Hidayat; B.A. Wijaya; B. Saputra; I.T. Rani; S. Kim; S. Lee; J. Yoo; B.B. Park; L. Suryanegara; M.A.R. Lubis
Abstract
BACKGROUND AND OBJECTIVES: The decreasing availability of fossil fuels requires the adoption of renewable energy sources that facilitate the mitigation of greenhouse gas emissions. Meeting Indonesia’s goal of achieving a 23 percent mixed energy composition by 2025 through co-firing demands a substantial ...
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BACKGROUND AND OBJECTIVES: The decreasing availability of fossil fuels requires the adoption of renewable energy sources that facilitate the mitigation of greenhouse gas emissions. Meeting Indonesia’s goal of achieving a 23 percent mixed energy composition by 2025 through co-firing demands a substantial increase in the availability of renewable energy sources. Bamboo is a valuable biomass resource because of its fast growth rate and potential for energy production. Innovative processes like torrefaction are necessary to improve the quality of biomass due to its challenging low density and hydrophilic properties. The objective of this study is to evaluate the characteristics of torrefied bamboo pellets made from Gigantochloa pseudoarundinacea by using a fixed counter-flow multi-baffle reactor. This study aims to investigate the properties and viability of torrefied G. pseudoarundinacea pellets for solid fuel applications to fill existing knowledge gaps about this technology’s potential.METHODS: A fixed counter-flow multi-baffle reactor was used to torrefy G. pseudoarundinacea bamboo pellets. The baffles in the reactor column held the pellets, while hot gas flowed through them. Torrefaction was conducted at 280 degrees Celsius with a 3–5 minutes resident time, and the gas flow rate was 4.25 cubic meters per minute. Torrefied pellets at the column bottom were counted as the first cycle. Three cycles of torrefaction were used, and each cycle was evaluated. The second and third cycles used torrefied pellets from the first and second cycles. The physical, chemical, and bioenergetic properties of the pellets before and after torrefaction were evaluated.FINDINGS: The bamboo pellets’ physical, chemical, and thermal properties changed significantly after torrefaction. Torrefaction at 285 degrees Celsius produced 78.5 percent of the production yield, according to thermogravimetric and derivative thermogravimetric analyses. Lightness, red/green, and yellow/blue chromaticity decreased, indicating darker, better solid fuel pellets. Torrefaction in the third cycle reduced moisture content by 99.8 percent. The lower moisture content reduced fungal growth, and improvinged biomass transport and storage. Torrefaction also raised the bamboo pellets’ calorific value and physical and mechanical properties. The highest calorific value of 21.62 megajoules per kilogram was obtained after the third cycle of torrefaction, and it was 16.6 percent higher than that of raw pellets. Torrefaction improved pellet grindability and combustion by decreasing density and compressive strength. Torrefaction increased ash, volatile matter, and fixed carbon. The ultimate analysis showed increased carbon and reduced nitrogen, hydrogen, and oxygen, improving solid fuel quality, energy density, and combustion emissions. According to a Fourier-transform infrared analysis, torrefaction caused extractive and hemicellulose degradation and lignin increase. The chemical analysis showed that temperature and residence time degraded hemicellulose and increased lignin in the torrefied pellets.CONCLUSION: The torrefaction process using a fixed counter-flow multi-baffle reactor demonstrated the enhanced properties of G. pseudoarundinacea bamboo pellets for their application as solid fuel. The study’s findings contribute to the comprehension of torrefaction and the enhancement of conditions for producing superior biomass products. These findings have implications for exploring the potential applications of torrefaction in diverse industries and energy sectors.
A. Suresh; S. Tamilvanan; K. Harini; H.V. Seventhi; R. Deepan Guna; R. Mahalakshmi; S. Suriyapriya; D. Sharmila; M. Thenmozhi
Abstract
Thenutrient medium used for the cultivation of microalgae adds more cost to its value-added product as well as the commercial scale application. Therefore in this study, focused feasibility of cattle urine as a cheap source of nutrients for microalgal growth, because, it contains various minerals and ...
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Thenutrient medium used for the cultivation of microalgae adds more cost to its value-added product as well as the commercial scale application. Therefore in this study, focused feasibility of cattle urine as a cheap source of nutrients for microalgal growth, because, it contains various minerals and economical which may support the growth of microalgae and reduce the medium cost. To check this, fresh cattle urine was collected, characterized, diluted and inoculated microalgae species Oscillatoria-SRA (Stagnant rainwater algae), Oscillatoria-CWA (Cooum waste algae), Chlorella and Synecocystis separately and incubated under fluorescent light with 8 hours light and 16 hours dark cycle. The biomass was quantified after 15 days and found out variation in biomass quantity in all microalgae isolates. The maximum of 2.6 g/L biomass was produced in Chlorella sp., at 10% urine, followed by Synechocystis sp., (2.25 g/L in 10% urine), Oscillatoria sp.,-SRA (1.3 g/L in 5% urine) and Oscillatoria sp.,-CWA (0.3 g/L in 1% urine). Moreover, lipid quantity was shown at the maximum of 12% dry weight in Oscillatoria sp-SRA., trailed by the 10% in Chlorella sp., 7% in Synecocystis sp., and the least of 5% in Oscillatoria sp-CWA. This study divulged that cattle urine alone is being able to support microalgae growth at a significant amount, thus convalescing industrial production of microalgae ultimately will reduce the cost of microalgal value-added products.
S. Gill; A. Al-Shankiti
Abstract
Composting of waste plant materials and its use in agriculture and landscape sites is an environmental friendly way of reducing waste material and conserving the environment. In this perspectives a survey has been performed at the Dubai based International Center for Biosaline Agriculture to compost ...
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Composting of waste plant materials and its use in agriculture and landscape sites is an environmental friendly way of reducing waste material and conserving the environment. In this perspectives a survey has been performed at the Dubai based International Center for Biosaline Agriculture to compost the plants based waste material (lawn cuttings-grass) to compost. The material was inoculated with a consortium of microbes leading to form stable and mature compost with high organic matter (38%). In order to conduct seed germination tests, Fulvic acid was extracted from the compost. A pot experiment was conducted over a period of 30 days in the green house to study the effect of Fulvic acid on the seed germination, and plant growth of Prosopis cineraria (L.) Druce (Ghaff) and Acacia tortilis (Forssk.) Hayne. Seeds of both trees were treated with Fulvic acid at 0.5% and 1% and water treatment was used as control. Generally seed germination and biomass were increased at both rates of fulvic acid. However, a pronounced increase was found in seed germination when fulvic acid was used at 1.0% (Prosopis cineraria 27%; Acacia tortilis 20% increase over control). Similarly biomass (shoot and root) of A. tortilis and P. cineraria was increase 34% and 94% respectively.
