scholarly journals Optimization of H2 Production through Minimization of CO2 Emissions by Mixed Cultures of Purple Phototrophic Bacteria in Aqueous Samples

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2015
Author(s):  
I.A. Vasiliadou ◽  
J.A. Melero ◽  
R. Molina ◽  
D. Puyol ◽  
F. Martinez
Keyword(s):  
Acetic Acid ◽  
Carbon Dioxide Emissions ◽  
Co2 Emission ◽  
Production Efficiency ◽  
Reducing Power ◽  
Value Added ◽  
H2 Production ◽  
Phototrophic Bacteria ◽  
Mixed Cultures ◽  
Production Of Hydrogen

One of the current challenges in the treatment of wastewater is the recovery and/or transformation of their resources into high value-added products, such as biohydrogen. The aim of the present study was to optimize the production of hydrogen by mixed cultures of purple phototrophic bacteria (PPB), targeting in low CO2 emission. Batch assays were conducted using different carbon (malic, butyric, acetic acid) and nitrogen (NH4Cl, Na-glutamate, N2 gas) sources by varying the chemical oxygen demand to nitrogen ratio (COD:N 100:3 to 100:44), under infrared radiation as sole energy source. Malate-glutamate (COD:N 100:5.5) and malate-NH4-N (COD:N 100:3) fed cultures, exhibited high H2 production rates of 2.3 and 2.5 mLH2/Lh, respectively. It was observed that the use of glutamate decreased the CO2 emission by 74% (13.4 mLCO2/L) as compared to NH4-N. The H2 production efficiency achieved by organic carbon substrates in combination with glutamate, was in the order of malic (370 mLH2/L) > butyric (145 mLH2/L) > acetic acid (95 mLH2/L). These substrates entailed partitioning of reducing power into biomass at 64%, 50% and 48%, respectively, whereas reductants were derived to biohydrogen at 5.8%, 6.1% and 2.1%, respectively. These results suggest that nitrogen source and carbon dioxide emissions play an important role in the optimization of hydrogen production by PPB.

scholarly journals Direct Fermentative Hydrogen Production from Cellulose and Starch with Mesophilic Bacterial Consortia

2020 ◽  
Vol 69 (1) ◽  
pp. 109-120 ◽  
Author(s):  
ROMAN ZAGRODNIK ◽  
RYSTYNA SEIFERT
Keyword(s):  
Acetic Acid ◽  
Hydrogen Production ◽  
Propionic Acid ◽  
Batch Process ◽  
H2 Production ◽  
Batch Processes ◽  
Anaerobic Sludge ◽  
Efficient Production ◽  
Bacterial Consortia ◽  
Production Of Hydrogen

Hydrogen produced from lignocellulose biomass is deemed as a promising fuel of the future. However, direct cellulose utilization remains an issue due to the low hydrogen yields. In this study, the long-term effect of inoculum (anaerobic sludge) heat pretreatment on hydrogen production from untreated cellulose and starch was evaluated during repeated batch processes. The inoculum pretreatment at 90°C was not sufficient to suppress H2 consuming bacteria, both for starch and cellulose. Although hydrogen was produced, it was rapidly utilized with simultaneous accumulation of acetic and propionic acid. The pretreatment at 100°C (20 min) resulted in the successful enrichment of hydrogen producers on starch. High production of hydrogen (1.2 l H2/lmedium) and H2 yield (1.7 mol H2/molhexose) were maintained for 130 days, with butyric (1.5 g/l) and acetic acid (0.65 g/l) as main byproducts. On the other hand, the process with cellulose showed lower hydrogen production (0.3 l H2/lmedium) with simultaneous high acetic acid (1.4 g/l) and ethanol (1.2 g/l) concentration. Elimination of sulfates from the medium led to the efficient production of hydrogen in the initial cycles – 0.97 mol H2/molhexose (5.93 mmol H2/gcellulose). However, the effectiveness of pretreatment was only temporary for cellulose, because propionic acid accumulation (1.5 g/l) was observed after 25 days, which resulted in lower H2 production. The effective production of hydrogen from cellulose was also maintained for 40 days in a repeated fed-batch process (0.63 mol H2/molhexose).

scholarly journals TiO2 Nanowires with Doped g-C3N4 Nanoparticles for Enhanced H2 Production and Photodegradation of Pollutants

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 254
Author(s):  
Liushan Jiang ◽  
Fanshan Zeng ◽  
Rong Zhong ◽  
Yu Xie ◽  
Jianli Wang ◽  
...  
Keyword(s):  
Environmental Governance ◽  
Fossil Fuels ◽  
H2 Production ◽  
Tio2 Nanowires ◽  
Photocatalytic Ability ◽  
Production Of Hydrogen ◽  
Growth Method ◽  
Renewable Hydrogen ◽  
Degradation Of Pollutants

With the rapid consumption of fossil fuels, along with the ever-increasing environmental pollution, it is becoming a top priority to explore efficient photocatalysts for the production of renewable hydrogen and degradation of pollutants. Here, we fabricated a composite of g-C3N4/TiO2 via an in situ growth method under the conditions of high-temperature calcination. In this method, TiO2 nanowires with a large specific surface area could provide enough space for loading more g-C3N4 nanoparticles to obtain C3N4/TiO2 composites. Of note, the g-C3N4/TiO2 composite could effectively photocatalyze both the degradation of several pollutants and production of hydrogen, both of which are essential for environmental governance. Combining multiple characterizations and experiments, we found that the heterojunction constructed by the TiO2 and g-C3N4 could increase the photocatalytic ability of materials by prompting the separation of photogenerated carriers. Furthermore, the photocatalytic mechanism of the g-C3N4/TiO2 composite was also clarified in detail.

scholarly journals UK Consumers’ Preferences for Ethical Attributes of Floating Rice: Implications for Environmentally Friendly Agriculture in Vietnam

2021 ◽  
Vol 13 (15) ◽  
pp. 8354
Author(s):  
Vo Hong Tu ◽  
Steven W. Kopp ◽  
Nguyen Thuy Trang ◽  
Andreas Kontoleon ◽  
Mitsuyasu Yabe
Keyword(s):  
Carbon Dioxide Emissions ◽  
Online Survey ◽  
Value Added ◽  
Environmentally Friendly ◽  
Trade Agreement ◽  
Co2 Emission Reduction ◽  
Global Food Security ◽  
Rice Farmers ◽  
Floating Rice ◽  
The Uk

Vietnam plays an important role in bearing global food security. However, Vietnamese rice farmers face several challenges, including pressures to develop sustainable livelihoods while reducing the environmental impacts of their production activities. Various Vietnamese agricultural restructuring policies were promulgated to promote the adoption of environmentally friendly practices to generate high value added for rice farmers, but the farmers are reluctant to adopt them because of perceived lack of demand. Decreasing consumption of rice in Asia and increasing demands in Europe shaped Vietnamese rice exporting policies. New trade agreements, such as the UK–Vietnam Free Trade Agreement, offer new target markets for Vietnamese rice farmers. This research provides empirical evidence related to the preferences of UK consumers for ethical attributes for floating rice imported from Vietnam. Floating rice represents a traditional method of rice cultivation that relies on the natural flooding cycle. Its cultivation uses very few agrochemical inputs and provides several other environmental, economic, and social benefits. In an online survey, the study used a choice experiment that asked 306 UK consumers to report their preferences for one kilo of floating rice with three non-market attributes: reduction in carbon dioxide emissions, allocation of profits to the farmers, and restitution of biodiversity. Overall, study participants favored the attributes of floating rice, but reported utility for only the “fair trade” attribute and for a marginal willingness to pay premiums for profit allocations to farmers. Consumers did not find value in either CO2 emission reduction or biodiversity improvement. Results from the study provide recommendations to develop agricultural programs, distribution strategies, and informational methods to encourage floating rice consumption in the UK.

Humic substances improve the co-production of hydrogen and carboxylic acids by anaerobic mixed cultures

2021 ◽  
Author(s):  
Paulina Núñez-Valenzuela ◽  
Rodolfo Palomo-Briones ◽  
Francisco J. Cervantes ◽  
Elías Razo-Flores
Keyword(s):  
Humic Substances ◽  
Carboxylic Acids ◽  
Mixed Cultures ◽  
Production Of Hydrogen

scholarly journals Valorization of secondary feedstocks from the agroindustry by selective catalytic oxidation to formic and acetic acid using the OxFA process

2021 ◽  
Author(s):  
Sebastian Ponce ◽  
Stefanie Wesinger ◽  
Daniela Ona ◽  
Daniela Almeida Streitwieser ◽  
Jakob Albert
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Reaction System ◽  
Value Added ◽  
Industrial Wastes ◽  
Raw Material ◽  
Gaseous Oxygen ◽  
Water As Solvent ◽  
Selective Catalytic Oxidation ◽  
Major Interest

AbstractThe selective oxidative conversion of seven representative fully characterized biomasses recovered as secondary feedstocks from the agroindustry is reported. The reaction system, known as the “OxFA process,” involves a homogeneous polyoxometalate catalyst (H8PV5Mo7O40), gaseous oxygen, p-toluene sulfonic acid, and water as solvent. It took place at 20 bar and 90 °C and transformed agro-industrial wastes, such as coffee husks, cocoa husks, palm rachis, fiber and nuts, sugarcane bagasse, and rice husks into biogenic formic acid, acetic acid, and CO2 as sole products. Even though all samples were transformed; remarkably, the reaction obtains up to 64, and 55% combined yield of formic and acetic acid for coffee and cocoa husks as raw material within 24 h, respectively. In addition to the role of the catalysts and additive for promoting the reaction, the influence of biomass components (hemicellulose, cellulose and lignin) into biogenic formic acid formation has been also demonstrated. Thus, these results are of major interest for the application of novel oxidation techniques under real recovered biomass for producing value-added products. Graphical abstract

scholarly journals Catalytic valorization of hardwood for enhanced xylose-hydrolysate recovery and cellulose enzymatic efficiency via synergistic effect of Fe3+ and acetic acid

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Kaixuan Huang ◽  
Lalitendu Das ◽  
Jianming Guo ◽  
Yong Xu
Keyword(s):  
Acetic Acid ◽  
Synergistic Effect ◽  
Paper Industry ◽  
Enzymatic Saccharification ◽  
Value Added ◽  
Lewis Acid Site ◽  
Aqueous Acetic Acid ◽  
Xylan Degradation ◽  
Hydrolysis Process ◽  
Xylonic Acid

Abstract Background Poplars are considered suitable dedicated energy crops, with abundant cellulose and hemicellulose, and huge surplus biomass potential in China. Xylan, the major hemicellulosic component, contributes to the structural stability of wood and represents a tremendous quantity of biobased chemicals for fuel production. Monomeric xylose conversion to value-added chemicals such as furfural, xylitol, and xylonic acid could greatly improve the economics of pulp-paper industry and biorefinery. Acetic acid (HAc) is used as a friendly and recyclable selective catalyst amenable to xylan degradation and xylooligosaccharides production from lignocellulosic materials. However, HAc catalyst usually works much feebly at inert woods than agricultural straws. In this study, effects of different iron species in HAc media on poplar xylan degradation were systematically compared, and a preferable Fe3+-assisted HAc hydrolysis process was proposed for comparable xylose-hydrolysate recovery (XHR) and enzymatic saccharification of cellulose. Results In presence of 6.5% HAc with 0.17–0.25 wt% Fe3+, xylose yield ranged between 72.5 and 73.9%. Additionally, pretreatment was effective in poplar delignification, with a lignin yield falling between 38.6 and 42.5%. Under similar conditions, saccharification efficiency varied between 60.3 and 65.9%. Starting with 100 g poplar biomass, a total amount of 12.7–12.8 g of xylose and 18.8–22.8 g of glucose were harvested from liquid streams during the whole process of Fe3+-HAc hydrolysis coupled with enzymatic saccharification. Furthermore, the enhancement mechanism of Fe3+ coupled with HAc was investigated after proof-of-concept experiments. Beechwood xylan and xylose were treated under the same condition as poplar sawdust fractionation, giving understanding of the effect of catalysts on the hydrolysis pathway from wood xylan to xylose and furfural by Fe3+-HAc. Conclusions The Fe3+-assisted HAc hydrolysis process was demonstrated as an effective approach to the wood xylose and other monosaccharides production. Synergistic effect of Lewis acid site and aqueous acetic acid provided a promising strategy for catalytic valorization of poplar biomass.

Modeling of Carbon Dioxide Measurement on Cement Plants

2012 ◽  
Vol 610-613 ◽  
pp. 2120-2128 ◽  
Author(s):  
Jun Xia Peng ◽  
Liang Huang ◽  
Yu Bo Zhao ◽  
Pan Chen ◽  
Lu Zeng ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Footprint ◽  
Carbon Dioxide Emissions ◽  
Co2 Emission ◽  
Firing Process ◽  
Input Output ◽  
Carbon Dioxide Measurement ◽  
Key Steps ◽  
Furnace Slag ◽  
Reducing Co2 Emission

Input-output model on cement plants were established. Carbon dioxide emissions of key steps and carbon footprint of products were calculated and predicted using the input-output model. The results showed that CO2 emission in the plant (the production of the plant is 1320000t a year) reached 910000 t a year and CO2 emission per ton product is 0.689 ton. Over 80% of the total CO2 was emitted during the process of firing，so the firing process is the key step for reducing CO2 emission in the cement plant. Carbon footprint of three kinds of cement products including ordinary portland cement, portland pozzolan cement and portland blast furnace slag cement are 0.76, 0.59, 0.72 respectively.

scholarly journals ENERGY-RELATED CARBON DIOXIDE EMISSIONS AND ENVIRONMENTAL EFFICIENCY IN THE EUROPEAN UNION AGRICULTURE: COMPARISON OF DIFFERENT BENCHMARKING TECHNIQUES

2016 ◽  
Vol 38 (3) ◽  
pp. 192-206 ◽  
Author(s):  
Tomas Baležentis ◽  
Daiva Makutėnienė
Keyword(s):  
Carbon Dioxide ◽  
European Union ◽  
Carbon Dioxide Emissions ◽  
Carbon Dioxide Emission ◽  
Value Added ◽  
The European Union ◽  
Undesirable Output ◽  
Energy Technologies ◽  
Desirable Output ◽  
Low Performance

The literature suggests different approaches towards modelling of the environmental impact caused by the production processes. The present paper attempts to establish a framework for multicriteria comparison of agricultural sectors of the European Union Member States and identify the performance gaps in terms of energy-related carbon dioxide emission. The research relies on the two approaches, viz. the by-production approach and the multi-criteria decision making approach. The environmental performance indicators were evaluated in regards to the desirable output (gross value added), inputs, and the undesirable output (carbon dioxide emission). The results indicate that Slovakia, Estonia, Lithuania, and Hungary should attempt to improve their carbon factors by implementing cleaner energy technologies. The combinations of by-production sub-indices suggest that productivity gains are more important for Sweden, Belgium, Poland, and France. Czech Republic, Latvia, and Finland are specific with low performance in terms of both the intended production and the undesirable output. The MCDM approach identified similar trends in performance as suggested by country ranking and correlation analysis.

scholarly journals RISK ANALYSIS OF INEFFICIENCY AT UKRAINE’S MACHINE BUILDING ENTERPRISES

2019 ◽  
Vol 2019 (3) ◽  
pp. 22-34
Author(s):  
Maryna AFANASIEVA ◽  
Keyword(s):  
Production Efficiency ◽  
Rank Correlation ◽  
Correlation Coefficients ◽  
Value Added ◽  
Risk Groups ◽  
Analysis Data ◽  
Risk Identification ◽  
Machine Building ◽  
Distribution Law ◽  
Market Capture

The paper considers the risk identification of inefficiency concerning 51 Ukrainian joint-stock companies of machine building in 2012–2017. The value added at factor cost (VA) is determined as the resulting indicator of production efficiency, which is a source of income of various social groups, so it contributes to combined efforts. To support advanced production and management technologies, rather than an extensive market capture, the multiplicative model of VA has been suggested with the VA share in output to assess the quality processes within the enterprise. Economic analysis of the annual public financial statements and the structural statistics were conducted to study proportion between the cost elements in sum of expenses with link to profit in net turnover for the main operating activity. As a result the models of two types of risk coefficient have been proposed. It has been verified by statistical analysis. Data were checked on submission to normal distribution law by Shapiro – Wilk test and homogeneity by coefficient of variation. With the help of nonparametric analysis of variance by Kruskal – Wallis test and Spearman rank correlation coefficients; it has been proved that risk groups differ from other enterprises and from each other statistically significantly. We conclude that 37% of the sample enterprises are risky; a third of this is the large and medium-sized companies. Advantages of the method in comparison with Ward clusterization were shown. When making decisions about resource allocation, it should be confirmed that the enterprise is risk-free according to algorithms provided. To improve situation it needs to apply sustainable development concept.

scholarly journals Capture, Storage and Utilization of Carbon Dioxide by Microalgae and Production of Biomaterials

2021 ◽  
Vol 25 (1) ◽  
pp. 574-586
Author(s):  
Marta Bertolini ◽  
Fosca Conti
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Carbon Capture ◽  
Extracellular Polymeric Substances ◽  
Incubation Temperature ◽  
Carbon Capture And Storage ◽  
Value Added ◽  
Culture Conditions ◽  
Transportation Systems ◽  
Operative Strategies

Abstract Carbon dioxide emissions are strongly related to climate change and increase of global temperature. Whilst a complete change in producing materials and energy and in traffic and transportation systems is already in progress and circular economy concepts are on working, Carbon Capture and Storage (CCS) and Carbon Capture and Utilisation (CCU) represent technically practicable operative strategies. Both technologies have main challenges related to high costs, so that further advanced research is required to obtain feasible options. In this article, the focus is mainly on CCU using microalgae that are able to use CO2 as building block for value-added products such as biofuels, EPS (Extracellular Polymeric Substances), biomaterials and electricity. The results of three strains (UTEX 90, CC 2656, and CC 1010) of the microalgal organism Chlamydomonas reinhardtii are discussed. The results about ideal culture conditions suggest incubation temperature of 30 °C, pH between 6.5 and 7.0, concentrations of acetate between 1.6 and 2.3 g L–1 and of ammonium chloride between 0.1 and 0.5 g L–1, the addition of glucose This green microalga is a valid model system to optimize the production of biomass, carbohydrates and lipids.

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