Waste Biomass from Marine Environment as Arsenic and Lead Biosorbent

2009 ◽  
Vol 71-73 ◽  
pp. 597-600 ◽  
Author(s):  
F. Beolchini ◽  
C. Pennesi ◽  
B. Testaferri ◽  
C. Totti ◽  
I. De Michelis ◽  
...  
Keyword(s):  
Marine Environment ◽  
Red Algae ◽  
Strong Dependence ◽  
Experimental Tests ◽  
Waste Biomass ◽  
Lead Uptake ◽  
Experimental Conditions ◽  
Arsenic Uptake ◽  
Metal Biosorption ◽  
Suspended Biomass

This paper deals with arsenic and lead biosorption by different waste biomasses coming from the marine environment. Shoreline seaweeds and seagrasses were used to adsorb metals from aqueous solutions, under different pH. Experimental tests were performed in order to study the equilibrium of biosorption with suspended biomass. The obtained results confirmed the possibility of using marine macrophyte biomass for heavy metal biosorption and evidenced a strong dependence of lead and arsenic uptake on the macrophyte structure. Brown algae were found to be the best sorbents for lead with a maximum observed lead uptake of 140 mg/g; green algae showed a maximum lead uptake in the range 50-70 mg/g; red algae were the worst lead sorbent, in the investigated experimental conditions, with a maximum lead uptake in the range 10-40 mg/g. As concerns arsenic, the macrophytes had in general good sorption abilities when compared with those of activated carbon. Furthermore red algae, that for lead were not effective, resulted to be the best sorbents for arsenic. This was explained by a different speciation in aqueous solution of lead (II), that is cationic with respect to arsenic(V), that is anionic.

scholarly journals High Voltage Electric Discharge for Recovery of Chlorogenic Acid from Tobacco Waste

2021 ◽  
Vol 13 (8) ◽  
pp. 4481
Author(s):  
Marija Banožić ◽  
Antun Jozinović ◽  
Jovana Grgić ◽  
Borislav Miličević ◽  
Stela Jokić
Keyword(s):  
Chlorogenic Acid ◽  
Process Parameters ◽  
Electric Discharge ◽  
High Voltage ◽  
Treatment Time ◽  
Strong Dependence ◽  
Extraction Procedure ◽  
Polynomial Equation ◽  
Experimental Conditions ◽  
Tobacco Waste

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on the content of chlorogenic acid. The content of chlorogenic acid ranged from 1.54 to 3.66 mg/100 g for scrap, from 1.90 to 2.97 mg/100 g for dust, and from 2.30 to 3.38 mg/100 g for midrib extract, showing a strong dependence on the applied process parameters. The temperature change and the change in pH and electrical conductivity of the extracts after high voltage discharge treatment were also observed. The studied process parameters showed a statistically significant effect on the chemical and physical properties of the extracts from tobacco waste as well as on the content of chlorogenic acid, indicating the potential of HVED assisted processes in the separation of chlorogenic acid from tobacco industry waste. Multiple regression analysis was used to fit the results for the chlorogenic acid to a second order polynomial equation and the optimum conditions were determined.

scholarly journals Digital Twinning Process for Stirred Tank Reactors/Separation Unit Operations through Tandem Experimental/Computational Fluid Dynamics (CFD) Simulations

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1511
Author(s):  
Blaž Oblak ◽  
Simon Babnik ◽  
Vivian Erklavec-Zajec ◽  
Blaž Likozar ◽  
Andrej Pohar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mixing Time ◽  
Tracer Tests ◽  
Flow Distribution ◽  
Experimental Tests ◽  
Cfd Simulations ◽  
Experimental Conditions ◽  
Separation Unit ◽  
Time Required

Computational fluid dynamics simulations (CFD) were used to evaluate mixing in baffled and unbaffled vessels. The Reynolds-averaged Navier−Stokes k–ε model was implemented in OpenFOAM for obtaining the fluid flow field. The 95% homogenization times were determined by tracer tests. Experimental tests were conducted by injecting sodium chloride into the vessel and measuring the conductivity with two conductivity probes, while the simulations replicated the experimental conditions with the calculation of the transport of species. It was found that the geometry of the system had a great effect on the mixing time, since the irregular flow distribution, which can be obtained with baffles, can lead to local stagnation zones, which will increase the time needed to achieve the homogenization of the solute. It was also found that measuring local, pointwise concentrations can lead to a high underestimation of the global mixing time required for the homogenization of the entire vessel. Dissolution of sucrose was also studied experimentally and by mathematical modeling. The dissolution of sucrose was found to be kinetically limited and a very good agreement was found between the experiments and the modeling approach. The extent of the applicability of CFD simulations was evaluated for enabling rapid process design via simulations.

Summing-up: deficiencies and future needs

1979 ◽  
Vol 286 (1015) ◽  
pp. 625-633 ◽  
Keyword(s):  
Marine Environment ◽  
Laboratory Experiments ◽  
Experimental Studies ◽  
Great Difficulty ◽  
Organic Production ◽  
Critical Examination ◽  
Experimental Conditions ◽  
Future Needs ◽  
Significant Harm ◽  
Fish And Shellfish

Although there are a great many experimental studies of particular pollutants and their effects, and some critical examination has been made of the mechanisms involved, there is great difficulty in determining whether such effects, if they are sublethal, occur in the sea. There is even more difficulty in deciding whether they produce significant harm in loss of organic production affecting, for example, the living resources of the sea: the stocks of fish and shellfish. Extrapolation from the results of laboratory experiments to the situation in the sea is hazardous because of the simplicity of experimental conditions in comparison with the complexity of the marine environment.

The Droplet Burning Characteristics of Algae-Derived Renewable Diesel, Conventional #2 Diesel, and Their Mixtures

2015 ◽  
Author(s):  
Yuhao Xu ◽  
Meilin Dong ◽  
Ivan Keresztes ◽  
Anthony M. Condo ◽  
Dan Phillips ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Gas Flow ◽  
Combustion Process ◽  
Complex Mixture ◽  
System Level ◽  
Waste Biomass ◽  
Renewable Diesel ◽  
Experimental Conditions ◽  
Validation Data ◽  
Concentric Spheres

Bio-derived fuels have received significant attention for their potential to reduce the consumption of petroleum-based liquid fuels, either through blending or direct use. Bio-feedstocks that employ algae, in particular heterotrophic microalgae, which convert sustainable plant sugars into renewable oils are especially attractive because the sugar that feeds this process can come from many sources — from sugarcane to corn, and even waste biomass, also known as cellulosic sugars. The microalgae grow in the dark and transforms sugar into nearly any oil type for almost any purpose anywhere, all while drastically compressing production time, from months and years to a matter of days. Much of the work in this area has focused on fuel production technologies. Little research has been reported on the combustion performance of algae-derived fuels, with most of the effort being directed to more system-level studies associated with combustion in engines. In this paper, we report the results of experiments that address some more fundamental multiphase combustion characteristics of algae-derived fuels relevant for spray combustion, namely a configuration involving a single isolated burning droplet. Experimental conditions are created that promote near spherical symmetry such that the gas flow arises primarily through the evaporation process (i.e., stationary droplets are ignited by spark discharge in stagnant air in the standard atmosphere and the droplet burning history is recorded in a free-fall facility that minimizes the influence of buoyant convection). The combustion symmetry that results, in which the droplet and flame are concentric spheres, facilitates the understanding of the combustion process while providing useful validation data for basic models of droplet burning that assume one-dimensional gas transport. Experiments were performed using algae-derived renewable diesel, and its performance was compared to #2 diesel fuel and a mixture of algal renewable diesel/#2 diesel (0.5 v/v). Additionally, the results of detailed chemical analysis are reported where it is shown that the composition of the algae-based diesel that was employed in the experiments was comprised of a complex mixture of aromatics and normal alkanes. The highly sooting propensity of these components resulted in droplet flames being luminous and producing soot during the burning history. A comparison of the flame brightness suggests that the sooting propensities are in the order of #2 diesel > renewable diesel #2 diesel blend > algae renewable diesel, which is consistent with observations of the sooting dynamics from back-lit droplet images. In spite of this difference in sooting propensities, algal renewable diesel droplets were found to have burning rates that are very close to #2 diesel and the mixture. Furthermore, the relative position of the flame to the droplet was almost indistinguishable for the fuels examined. These results suggest that algae renewable diesel could potentially be considered a drop-in replacement for conventional diesel fuel, or at the least serve as a useful additive to reduce the consumption of petroleum-based #2 diesel fuel.

scholarly journals APPLICATION OF BAYESIAN TECHNIQUE FOR PARAMETER ESTIMATION IN A FERMENTATIVE PROCESS

2020 ◽  
Vol 19 (1) ◽  
pp. 105
Author(s):  
C. A. Azevedo ◽  
C. T. Falcón ◽  
D. C. Estumano
Keyword(s):  
Parameter Estimation ◽  
Experimental Tests ◽  
Parameters Estimation ◽  
Operating Conditions ◽  
Biofuel Production ◽  
Experimental Conditions ◽  
Data Set ◽  
Operating Strategies ◽  
Log Normal ◽  
Fermentative Process

In the current world scenario, there has been noted an increase of researches on biofuel production, more specifically bioethanol, produced from biomass, in order to obtain more information to analyze, understand and optimize this fermentative process. The modelling process, which include the determination of a kinetic model and its respective parameters, is a fundamental step in defining operating strategies and understand how the experimental conditions can affect the optimal system operating conditions. The present work employs a bayesian technique to estimate the parameters of a classical kinectic model used by Silva and collaborators (2016), because, unlike the classical techniques, it is possible to take into account the uncertainty of the measurements and the prior knowledge of the parameters can be accounted for in probabilistic terms. In this context, by using simulated measurements, for the parameters estimation it is propose a sensitivity analysis of the parameters model to define the most relevant ones to be estimate and the use of the Monte Carlo Markov Chain method through the Metropolis-Hastings algorithm, evaluating the influence of four types of priori probability distribution of data set: uniform, gaussian, log-normal and Rayleigh. The obtained results showed that the sensibility analysis is an important step on parameter estimation and algorithm used was satisfactory in estimating the parameters of the kinectic model used, demonstrating the possibility of using it as a tool for time and cost reduction in experimental tests.

scholarly journals Current Research Trends on the Effects of Microplastics in Soil Environment Using Earthworms: Mini-Review

2021 ◽  
Vol 43 (4) ◽  
pp. 299-306
Author(s):  
Jaeryung Hur ◽  
Eun Hea Jho
Keyword(s):  
Marine Environment ◽  
Human Life ◽  
Exposure Period ◽  
Soil Environment ◽  
Single Exposure ◽  
Experimental Conditions ◽  
Test Species ◽  
Oxidation Stress ◽  
Induced Changes ◽  
The Impact

Objectives : The increase in the amount of plastics used has brought convenience to human life, but has also caused various environmental problems such as problems related to microplastics. Microplastics are defined as small plastic particles with a size of under 5 mm. As of now, research on microplastics has been largely focusing on the marine environment, and studies on microplastics in soil environment are on the rise in very recent years. Thus, the environmental impact of microplastics on the soil environment are insufficient than those on the marine environment, and there is a need for more studies. Therefore, this mini-review attempts to examine the studies on microplastics in soil environment focusing on the studies using earthworms as a test species.Methods : Published studies on microplastics in soil environment were identified by searching Web of Science. The focus of this mini-review was to gather the published articles reporting the effect of microplastics on earthworms in the absence and presence of other chemical contaminants.Results and Discussions : The number of studies evaluating the effect of microplastics in soil are significantly increasing, and earthworms are being mostly used as the test species. Experimental conditions were divided into two types: Single exposure to microplastics and combined exposure to microplastics and other chemicals. In most studies, changes in the biomarkers which are related to oxidation stress of earthworms were confirmed, and direct damage to intestinal tissues of earthworms was also observed. However, in the case of the changes of the biomarkers of earthworms, their patterns were different depending on the experimental conditions (i.e., concentrations of microplastics and chemicals, microplastics size and type, exposure period, etc.). Also, the avoidance behavior of earthworms and the internal accumulation of microplastics and co-existing chemicals were not consistent among the studies. Thus, the effects of microplastics on earthworms are not clear yet, although they seem to have some adverse effects.Conclusions : This study showed that the interest in the impact of microplastics in the soil environment has been increased recently, and earthworms are being used mostly in the studies. Yet, there is no standardized method to study the effect of microplastics on earthworms. Studies so far confirmed that microplastics induced changes in and outside of earthworm bodies. However, due to various experimental conditions, it seemed that consistent results could not be confirmed in those researches. For that reason, this study suggests that standardized research methods for microplastics researches using earthworms as a test species need to be established and need to be applied to further studies.

scholarly journals Synthesis, Characterization, and Synergistic Effects of Modified Biochar in Combination with α-Fe2O3 NPs on Biogas Production from Red Algae Pterocladia capillacea

2021 ◽  
Vol 13 (16) ◽  
pp. 9275 ◽  
Author(s):  
Mohamed A. Hassaan ◽  
Ahmed El Nemr ◽  
Marwa R. Elkatory ◽  
Safaa Ragab ◽  
Mohamed A. El-Nemr ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Red Algae ◽  
Biogas Production ◽  
Synergistic Effects ◽  
Fourier Transform Infrared ◽  
Logistic Function ◽  
Gravimetric Analysis ◽  
Waste Biomass ◽  
Biogas Yield ◽  
Modified Biochar

This study is the first work that evaluated the effectiveness of unmodified (SD) and modified biochar with ammonium hydroxide (SD-NH2) derived from sawdust waste biomass as an additive for biogas production from red algae Pterocladia capillacea either individually or in combination with hematite α-Fe2O3 NPs. Brunauer, Emmett, and Teller, Fourier transform infrared, thermal gravimetric analysis, X-ray diffraction, transmission electron microscopy, Raman, and a particle size analyzer were used to characterize the generated biochars and the synthesized α-Fe2O3. Fourier transform infrared (FTIR) measurements confirmed the formation of amino groups on the modified biochar surface. The kinetic research demonstrated that both the modified Gompertz and logistic function models fit the experimental data satisfactorily except for 150 SD-NH2 alone or in combination with α-Fe2O3 at a concentration of 10 mg/L. The data suggested that adding unmodified biochar at doses of 50 and 100 mg significantly increased biogas yield compared to untreated algae. The maximum biogas generation (219 mL/g VS) was obtained when 100 mg of unmodified biochar was mixed with 10 mg of α-Fe2O3 in the inoculum.

scholarly journals ANN Modeling For Forecasting of VCR Engine Performance And Emission Parameters Fuelled With Green Diesel Extracted From Waste Biomass Resources

2021 ◽  
Author(s):  
Rajayokkiam Manimaran ◽  
Thangavel Mohanraj ◽  
Moorthy Venkatesan
Keyword(s):  
Diesel Fuel ◽  
Research Work ◽  
Load Condition ◽  
Engine Performance ◽  
Experimental Tests ◽  
Waste Biomass ◽  
Ann Model ◽  
Green Diesel ◽  
Performance And Emission ◽  
Smoke Opacity

Abstract In this research work, the experimental tests were conducted on a single-cylinder, constant speed, variable compression ratio (VCR) engine fuelled with green diesel extracted from waste trichosanthes cucumerina seeds. The engine test blends are prepared with different trichosanthes cucumerina biodiesel (TCB) proportions of 30%, 50% and 70% in diesel fuel, and their thermo-physical properties were assessed as per the ASTM standards. At full load condition, the TCB30 blend operated at the CR 18:1 gives better engine performance and reduced emission levels of HC by 13.51%, CO by 10.82% and smoke opacity by 16.87%, equated with neat diesel fuel. With the support of experimental results, the performance (BTE, BSFC and EGT) and emission parameters (HC, CO, NOx, smoke opacity and CO2) are predicted using multiple regression artificial neural network (ANN) model. This trained ANN model results in an average correlation coefficient (R2) value is 0.9967, which is closer to 1. It indicates that the proposed ANN model can generate the exact correlation between input factors and output responses.

scholarly journals Analysis of draught discomfort prediction models

2021 ◽  
Vol 2069 (1) ◽  
pp. 012236
Author(s):  
S M Hooshmand ◽  
S A Zolfaghari ◽  
J Toftum
Keyword(s):  
Environmental Conditions ◽  
Indoor Environment ◽  
Prediction Models ◽  
Thermal Conditions ◽  
Experimental Tests ◽  
High Accuracy ◽  
Maximum Deviation ◽  
Experimental Conditions ◽  
The Common ◽  
The Mean

Abstract One of the common local thermal discomforts that happen in an indoor environment is draught. Because of the importance of draught, many studies have been carried out to develop equations to calculate the draught rate. But because these equations are obtained from experimental tests in narrow experimental windows, their accuracy under wider environmental conditions should be analyzed. In this paper, the accuracy of equations obtained from the literature were investigated. Each equation predicted the draught rate with high accuracy and mean error of 5.3, 6.8, and 2.2% under the thermal conditions in which the equation was obtained. When applying the equations to different thermal conditions, the mean and maximum errors significantly increased and showed errors in predicting the draught rate with a maximum deviation of 63.5, 51.6, and 49.7%. These equations in some cases, even could not predict the draught rate of the reported draught discomfort percentage. Based on the results, each equation had its limitations and none of the studied equations could accurately predict the draught rate in all experimental conditions. An index that considers all relevant parameters in predicting draught discomfort can lead to a better draught rate prediction.

Experimental Profiles of the Balmer Line Hβ Emitted from an Afterglow Plasma Without and With a Superposed Magnetic Field up to 10 Tesla

1979 ◽  
Vol 34 (9) ◽  
pp. 1041-1050 ◽  
Author(s):  
H. W. Drawin ◽  
J. Ramette
Keyword(s):  
Magnetic Field ◽  
Stark Effect ◽  
Strong Dependence ◽  
Axial Direction ◽  
Hydrogen Gas ◽  
Balmer Line ◽  
Pure Hydrogen ◽  
Experimental Conditions ◽  
Line Structure ◽  
Afterglow Plasma

Abstract The profile of the Hβ line emitted from an afterglow plasma in pure hydrogen gas and a mixture of hydrogen and helium has been measured in axial direction using a multichannel spectrum analyzer with additional temporal resolution. Measurements were performed without and with a superposed magnetic field (B ≦ 10.8 Tesla) in axial direction. With magnetic field we observed a rather strong dependence of the wavelength positions of the two lateral "Zeeman components" (intensity maximum due to combined Stark-Zeeman effects). This feature is important in radiative transfer calculations and for the spectroscopic determination of magnetic fields in plasmas. - Both with and without magnetic field we always observed a line structure superposed on the Hβ profile. The structure disappeared in an active electrical discharge and changed with gas composition. The line structure is interpreted as being due to electronic transitions of molecular hydrogen. It is very probable that the "satellite structures" of Balmer lines observed by other authors under quite different experimental conditions and interpreted as dynamical Stark effect splitting due to fluctuating electric fields have in most cases the same molecular origin. Our earlier published line profiles of Hβ for B = 0 [J. Ramette and H. W. Drawin, Z. Naturforsch. 31 a, 401 (1976) ] are revised in the present paper.

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