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The construction industry had approached a critical limit which led to the increase of cement production. The production of cement would cause a broader environmental implication. Cement production is a major source of carbon dioxide emission. Carbon dioxide gas contributes about 63.33% of global warming since the production of one ton of cement would emit about one ton of carbon dioxide to the environment. To mitigate this issue, the research community has investigated the use of waste materials that possess similar chemical properties with cement content as a material for partial cement replacement. The use of rice husk ash has shown to be a contending candidate in the literature. Therefore, this paper attempts at reviewing the performance of rice husk ash as partial cement replacement. It could be observed from the literature that concrete with 5% up to 15% of rice husk ash showed an equivalent performance to ordinary concrete in compressive, flexural, and tensile strength. Thus, rice husk ash can be used as a material replacement in concrete and reduces pollution that originates from cement production and open burning of rice husk.

Construction sludge frequently has high alkalinity after its generation or during the intermediate treatment process. The aim of this study is to experimentally investigate the potential of combining accelerated carbonation and a paper sludge ash-based stabilizer (PSAS) to neutralize the alkalinity of construction sludge in a short period and to improve its strength for use as a recycled material. The experimental results indicate that the addition of a PSAS significantly granulated the alkaline sludge, and once granulated, the PSAS successfully accelerated the pH neutralization of the alkaline sludge. It was also found that the decrease in dry density ρd and the degree of saturation Sr of the PSAS-treated sludge was able to reduce the period required for the pH neutralization, tN. The decrease in ρd is thought to allow fresh CO2 gas to penetrate the specimen more easily. However, if Sr is below a certain limit, it does not strongly facilitate the reduction of tN. This implies that pH neutralization cannot be accelerated when the amount of water in the sludge is below a certain level. Moreover, it was found that mean particle diameter D50 also affected tN. The strength development of the PSAS-treated sludge was evaluated using a series of cone index tests. It was found that the strength of the alkaline sludge without the PSAS was significantly decreased by accelerated carbonation, but was significantly increased even after accelerated carbonation when the PSAS was present. Due to the porosities of the remaining PS ash particles, most of the contribution of the water absorption and retention performance of the PSAS to the strength development of the PSAS-treated sludge was secured after accelerated carbonation. In addition, the granulated particles of the PSAS-treated sludge retained their granular shape to some extent. Therefore, it is presumed that the friction and interlocking of the particles did not decrease significantly. It was also found that, after carbonation, the qc of the PSAS-treated sludge increased more rapidly than that of the alkaline sludge without the PSAS. A further detailed examination of the test results showed that under air-curing conditions, the qc of the treated sludge with accelerated carbonation increased relatively gradually compared to that of the treated sludge without accelerated carbonation.

Here in this study, co-pyrolysis of paper mill sludge (PMS) and spent coffee ground (SCG) was conducted to mainly recover energy and additionally produce engineered biochar as an adsorbent. More specifically, to enhance the generation of syngas (H 2 and CO) through co-pyrolysis of PMS and SCG and modify the physico-chemical properties of biochar, carbon dioxide (CO 2 ) was used as reaction medium. The CO 2 co-feeding impact on co-pyrolysis with various mass ratios of PMS and SCG was also evaluated to explore any catalytic effects arising from CO 2 and Fe/Ca species in PMS. The decrease in pyrolytic oil substances was apparent due to the synergistic effects of CO 2 and Fe/Ca species. Moreover, the generation of CO was catalytically enhanced in the presence of Fe/Ca species in PMS. Co-pyrolysis in CO 2 not only converted the impregnated Fe ions into magnetite (Fe 3 O 4 ), but also created porous biochar. One biochar fabricated at the optimal mass ratio (PMS:SCG = 7:3) exhibited the highest adsorption capability toward As(V) due to adequate balancing between the amount of Fe/Ca solid minerals and biochar porosity. As a result, co-pyrolysis using CO 2 as reaction medium can be a feasible option for the generation of CO along with production of biochar as a byproduct which can be used in environmental application.

Utilization of the quality-upgraded waste paper in the manufacture of paper and board will reduce the wood consumption and pulping energy. While the optical property of the fibers from recycled old newspaper is very poor, in-situ calcium carbonate formation on those fibers by injecting carbon dioxide to the mixed slurry of those pulp and calcium oxide improved their brightness. Upgrading recycled old newspaper to substitute more expensive wood furnish, such as recycled old magazine, was successfully demonstrated in the present study. This study showed that the in-situ calcium carbonate formation process improved the optical quality of the recycled old newspaper by covering colored impurities with newly formed calcium carbonate, and improved calcium carbonate retention in papermaking process by attaching them to fibers. The strength reduction by the presence of newly formed calcium carbonate in the paper was recovered by adding strength agent. High ash retention at high ash content under the strong turbulence in the modern paper mill was achieved by the application of the in-situ calcium carbonate formation method. The quality-upgrade of recycled fibers and cost saving in the manufacture of duplex paperboard were demonstrated in the mill trial.

Pyrolysis of paper mill sludge (PMS) was conducted to produce syngas (H 2 and CO) and fabricate magnetic biochar (PMS biochar) for use as an adsorbent for As(V). The enhanced generation of CO was observed in the CO 2 atmosphere due to reactions triggered by CO 2 . Particularly, the generation of syngas from pyrolysis of PMS in CO 2 (9.6 mol% at 720 °C) was superior to the cases of pyrolysis of acid-washed PMS ( i.e. , minerals-eliminated PMS) in CO 2 (2.9 mol% at 720 °C), which evidences catalytic effects attributed by Fe and Ca species contained in PMS. Based on the results of X-ray diffraction (XRD), pyrolysis of PMS in CO 2 led to the conversion of Fe species into magnetite (Fe 3 O 4 ) solid phase that imparted the magnetic property to the biochar (saturation magnetization: 28.4 emu g −1 ). The PMS biochar exhibited high As(V) adsorption capacity of 34.1 mg g −1 in a given condition, which could be attributed to the great adsorption affinity of Fe 3 O 4 /CaCO 3 mixture toward As(V). The integrated approach for the utilization of PMS could satisfy growing demand for renewable energy and environmental sustainability.

The CO2 concentration in the atmosphere is increasing and threatening the earth's climate. Selective CO2 capture at large point sources will help to reduce the CO2 emissions to the atmosphere. Biochar with microporous structure could be a potential material to capture CO2. The impact of feedstock type, pyrolysis temperature and steam activation of biochars were evaluated for CO2 adsorption capacity. Pine sawdust biochars were produced at 550 °C, and steam activated for 45 min at the same temperature after completing the pyrolysis (PS550 and PSS550). Paper mill sludge biochars were produced at 300 and 600 °C (PMS300 and PMS600). The CO2 adsorption capacity of biochars was tested at 25 °C using a volumetric sorption analyzer. Pine sawdust biochars showed significantly higher CO2 adsorption capacity than paper mill sludge biochars due to high surface area and microporosity. Pine sawdust biochars were then evaluated for dynamic adsorption under representative post-combustion flue gas concentration conditions (15% CO2, 85% N2) using a breakthrough rig. Both materials showed selective CO2 uptake over N2 which is the major component along with CO2 in flue gas. PSS550 had slightly higher CO2 adsorption capacity (0.73 mmol g^-1 vs 0.67 mmol g^-1) and CO2 over N2 selectivity (26 vs 18) than PS550 possibly due to increase of microporosity, surface area, and oxygen containing basic functional groups through steam activation. Pine sawdust biochar is an environmentally friendly and low-cost material to capture CO2.

The 2011 White Paper on Transport of the European Commission spells out a series of targets for 2030 and 2050. One of the 10 targets is explicitly related to urban transport and stipulates: “Halve the use of ‘conventionally fuelled’ cars in urban transport by 2030; phase them out in cities by 2050. Achieve essentially CO2-free city logistics in major urban centres by 2030.” With this paper we present and discuss a roadmap that deals with the question who needs to do what by when in order to reach the White Paper goal for urban transport. The “stakeholder-driven” roadmap was developed in the FP7 project TRANSFORuM. The paper will present the key findings and the suggested action steps identified in the roadmap. The paper will also exemplify three possible urban transformation pathways towards the urban target. This approach emerged from stakeholder consultations which highlighted the need to take into account the widely differing conditions among European cities.

Straw pulp in China, which is the world's largest producer of this material, suffers from water and energy shortages during its entire life cycle. However, limited systematic studies have focused on these issues, and decision makers need be provided with improvement methods for the environmental performance. Thus, an impact-oriented energy and carbon coupled water footprint analysis was conducted in this study based on ISO standards. Results showed that the impact of energy consumption and carbon emissions exceeded that of water footprint. Carcinogens, non-carcinogens, and freshwater ecotoxicity also played effective roles in improving the environmental performance. Optimizing key indirect processes, including chemicals production, steam preparation, electricity generation, wood pulping, and fertilizer recovery, dominated the reduction in environmental burdens. Direct freshwater consumption and wastewater disposal played additional effective roles in controlling water footprint. The water network was thus optimized by a water pinch analysis to decrease the freshwater consumption and pollutant emissions by maximum values of 91.5% and 99.7% after optimization, respectively. Meanwhile, carbon dioxide, methane, chromium, arsenic, mercury, titanium, copper, strontium, total nitrogen, total phosphorus, BOD5, and COD were the main pollutants. Overall, the environmental impact can be further reduced by diminishing coal power ratio in national energy structure, adopting recovered steam, and considering multistage regeneration water network to cope with different water use demands.

In cigarette production, the cellulosic paper essentially derived from flax fibers or other fiber materials is used as the wrapping material. During smoking of cigarettes, the highly toxic carbon monoxide is produced. To decrease the amount of carbon monoxide emission in the mainstream smoke, the engineering of all cigarette components including cellulosic cigarette paper and tobacco column is critical. This review summarizes the concepts related to engineering of cigarette paper. These mainly include permeability control, increased use of burn additives, optimization of fiber basis weight, engineering of calcium carbonate fillers, and incorporation of catalysts/oxidants. In particular, catalytic and/or oxidative conversion of carbon monoxide to carbon dioxide has been very widely reported. The control of permeability/diffusivity of cigarette paper is also of critical importance for enhanced diffusion of carbon monoxide out of the cigarette. The development of new concepts and combination of various concepts may lead to breakthroughs in this area.

The adsorption/desorption cycles of the alkaline paper mill waste (APMW) can be used to remove CO 2 from coal-fired power plants. In this work, the prolonged adsorption duration treatment was used to modify CO 2 capture behavior of the raw and the prewashed APMW in the multiple adsorption/desorption cycles. The effects of increased duration of adsorption and CO 2 partial pressure in the first cycle on the fractional adsorption of CO 2 and adsorption rate were investigated, when the raw and the prewashed APMW are employed as the sorbents. The cyclic CO 2 capture behavior of APMW after the repeated prolonged adsorption in different cycles was also studied. For the raw and the prewashed APMW as the sorbents, 9–12 h adsorption of CO 2 just in the 1st cycle enhances the cyclic fractional adsorption of CO 2 and adsorption rate of CO 2 in the 1st cycle and the subsequent cycles. The repeated prolonged adsorptions in the various cycles are more effective to increase the cyclic CO 2 capture capacity of APMW than only in the 1st cycle. The longer adsorption duration results in larger area and volume of pores in 10–100 nm in diameter for CaO derived from APMW after the next cycles, which are helpful to cyclic CO 2 capture of APMW. The raw and the prewashed APMW can retain high CO 2 adsorption reactivity by the prolonged adsorption duration treatment in the multiple adsorption/desorption cycles.

The pulp and paper industry is placed in a unique position as biomass used as feedstock is now in increasingly high demand from the energy sector. Increased demand for biomass increases pressure on the availability of this resource, which might strengthen the need for recycling of paper. In this study, we calculate the energy use and carbon dioxide emissions for paper production from three pulp types. Increased recycling enables an increase in biomass availability and reduces life-cycle energy use and carbon dioxide emissions. Recovered paper as feedstock leads to lowest energy use (22 GJ/t) and CO2 emissions (−1100 kg CO2/t) when biomass not used for paper production is assumed to be converted into bio-energy. Large differences exist between paper grades in e.g. electricity and heat use during production, fibre furnish, filler content and recyclability. We found large variation in energy use over the life-cycle of different grades. However, in all paper grades, life-cycle energy use decreases with increased recycling rates and increased use of recovered fibres. The average life-cycle energy use of the paper mix produced in The Netherlands, where the recycling rate is approximately 75%, is about 14 GJ/t. This equals CO2 savings of about 1 t CO2/t paper if no recycled fibres would be used.

A new method, microwave pyrolysis, has been investigated to dispose the paper mill sludge. Microwave pyrolysis is a new fast pyrolysis technology for biomass. The effects of various different factors on paper mill sludge’s microwave pyrolysis were mainly discussed. The results showed that the mass of the paper mill sludge reduced very rapidly within the first 6 min and then flattened out with the microwave reaction time increasing; The greater the microwave power was, the faster the sludge’s pyrolysis and the more the smell and concentration of diesel smoke was; The pyrolysis performance was better when the dosage of the paper mill sludge was increased and of 5% NaOH was added as microwave absorbers; Under CO2 atmosphere, the pyrolysis performance was the best when of 5% NaOH was added, while under N2 atmosphere, the pyrolysis performance was the best when of 5% ZnCl2 was added.

Secondary pulp/paper-mill sludge (SPP) and sewage sludges (primary, secondary, and digested sewage sludges) were treated in supercritical water at temperatures ranging between 400 degrees Celsius and 550 degrees Celsius over 20-120 min for energy recovery. Low temperature and short reaction time favored the formation of heavy oil (HO) products, which were mainly composed of a variety of phenol and phenolic compounds, as well as some nitrogen-containing compounds, long-chain alkenes and alcohols, etc., with high gross calorific values (>36 MJ/kg). By contrast, the formation of synthetic gases, a mixture of hydrogen, carbon monoxide, carbon dioxide, methane, and other light hydrocarbons, were not significantly affected by reaction time but greatly enhanced with increasing temperature. The highest gas yield was obtained at 550 degrees Celsius, where 37.7 wt.% of the SPP (on dry basis) was converted into gases, with hydrogen yields as high as 14.5 mol H(2)/kg SPP (on a dry basis). In comparison to sewage sludges, SPP exhibited a greater capability for the production of HO and gases owing to its higher contents of volatiles and alkali metals, indicating a prospective utilization potential for SPP as a source of bio-energy.

The presence of paper in municipal solid waste (MSW) interferes with the efficiency of composting plants. The compost feedstock to these plants is between 12% and 27% paper on a dry weight basis, with an initial C:N ratio ranging from 32:1 to 57:1. Tests of the last aerobic biodegradability (LAB) of the type of paper present in paper and cardboard packaging were carried out, following UNE-EN 14046 standards. The results obtained, measured through the quantity of CO(2) generated over 45 days, compared with the maximum that could be produced (ThCO(2)), showed that the presence of paper retards, to a great degree, the biodegradation of organic material in general. Specifically, the presence of papers with a degradation D (%) >60% at 45 days (white (W) and recycled paper (R)) could be allowed, but always in proportions that did not exceed 27% in dry weight. These results can be achieved with an industrial level process, pre-treated by trituration.

This study examines the historical relation between carbon dioxide emission and output growth in the Swedish pulp and paper industry from 1973 to 2006. We find that the industry achieved an 80 perc ...

This report demonstrates the fastest technique to successfully achieve carboxymethyl cellulose (CMC) from office paper waste, within 30 min at ambient temperature using ultrasonic-assisted method as a source of energy. The obtained CMC was characterized using FTIR, TGA, and NMR techniques to confirm its structure. The FTIR spectrum showed characteristic peaks of carboxymethyl groups and its salt at the wavenumbers of 1585 (C=O) and 1412 (C-O) cm−1. The TGA results of CMC exhibited the loss of carbon dioxide at ca. 260 – 300 °C. Moreover, a higher ash yield of the obtained CMC indicated the substitution of carboxymethyl in the structure. The CMC product structure was confirmed using 13C- and HMBC 2D-NMR. The HMBC 2D-NMR results indicated a correlation between carbonyl and methylene carbons of carboxymethyl groups and protons of pyranose ring, implying that pyranose ring was substituted successfully by monocholoroacetic acid (MCA). The optimal conditions were obtained by using 4.11 ml of 30%w/v NaOH and 1.4 g of MCA in 40 ml of isopropanol at ambient temperature. The resulting CMC showed 0.75 degree of substitution at 18.75 W/ml ultrasonic intensity.

Gene expression responses of paper birch ( Betula papyrifera ) leaves to elevated concentrations of CO 2 and O 3 were studied with microarray analyses from three time points during the summer of 2004 at Aspen FACE. Microarray data were analyzed with clustering techniques, self-organizing maps, K -means clustering and Sammon's mappings, to detect similar gene expression patterns within sampling times and treatments. Most of the alterations in gene expression were caused by O 3 , alone or in combination with CO 2 . O 3 induced defensive reactions to oxidative stress and earlier leaf senescence, seen as decreased expression of photosynthesis- and carbon fixation-related genes, and increased expression of senescence-associated genes. The effects of elevated CO 2 reflected surplus of carbon that was directed to synthesis of secondary compounds. The combined CO 2 + O 3 treatment resulted in differential gene expression than with individual gas treatments or in changes similar to O 3 treatment, indicating that CO 2 cannot totally alleviate the harmful effects of O 3 .

Ornithine decarboxylase has been measured in midterm mouse placentas by a simple inexpensive method. The reaction vessel was a special plastic scintillation vial. The 14CO2 liberated from dl -1-14C-ornithine was absorbed by a Hyamine hydroxide impregnated blotting paper disc cemented into the vial's cap. This was released into the toluene fluor of another scintillation vial by transfer of the cap after loosening the paper disc. The incubation vial was further adapted by predrilling a hole in its side to permit addition of acid to stop incubation and drive 14CO2 out of solution. This hole was kept sealed with tape. The preference of Hyamine over ethanolamine/2-methoxyethanol mixture (2:1) was established. Also the protective value of EDTA and dithiothreitol and the deleterious effect of freezing and thawing on this enzyme were studied. Mouse placentas contain a relatively large amount of ornithine decarboxylase. This method of assay should be suitable for quantification of other decarboxylases whenever suitable carboxyl-labeled substrates are available.

A new, quantitative radioassay for ornithine decar☐ylase is described which involves determination of putrescine, the organic product of the reaction. The assay is based on the selective adsorption and retention of putrescine by Whatman CM 82 paper, a weak cation exchanger, and is compatible with the variety of assay conditions routinely employed in which released 14CO2 is measured. A rapid, semiquantitative variation of the assay which should be useful for mass screening procedures is also presented.

1. 1. Detached leaves of beet, swiss chard, and tobacco were found to produce large amounts of glutamine when supplied with NH 4 NO 3 in light. After an initial lag phase of 24 hr., the glutamine content of swiss chard leaves rose rapidly and continuously for at least 5 days, reaching a value of 5% of the fresh leaf weight. This glutamine was derived from photosynthetic carbon and was in dynamic equilibrium with the leaf carbohydrates. 2. 2. A method for the biosynthesis of radioactive glutamine was developed. A detached swiss chard leaf is supplied with 0.1 M NH 4 NO 3 for 48 hr. under continuous illumination. C 12 O 2 is fed during the first 24-hr, period, and C 14 O 2 during the second. In an experiment performed under these conditions, 28% of the fed C 14 was incorporated into glutamine. 3. 3. Since chemical isolation of glutamine from a leaf resulted in a product of low purity and specific activity, a Chromatographic technique has been evolved. Using this technique, 71.6% of the available glutamine was recovered from a leaf. This glutamine was over 99% pure. The final product from a 1 mc. feeding to one swiss chard leaf was 96.5 mg. of uniformly labeled glutamine with a specific activity over 4 × 10 6 counts/mm.

The present paper aims to develop sustainable concrete to reduce the impact of concrete on environment using groundnut husk ash. In the present study, Life Cycle Assessment (LCA) of concrete is evaluated in terms of Global Warming Potential (GWP), Acidification Potential (AP), and Eutrophication Potential (EP) which indicates the impact of Carbon Dioxide (CO2) and other gases emission on environment during manufacturing of concrete. Six types of concrete cubes i.e CM, G-2.5, G-5, G-7.5, G-10, G-12.5, and G-15 designed concrete are manufactured by replacing cement with GHA by mass at different replacement levels (0%,2.5%, 5%, 7.5%, 10%, 12.5% and 15%).Cubes were tested for compressive strength after 7 and 28 days. Results indicated that upto 12.5% replacement of cement with groundnut husk ash (GHA) by mass, the compressive strength of GHA was more than the characteristic strength of M20 grade concrete. LCA of control mix and GHA concrete was done from cradle – to – gate boundaries. In control mix concrete, cement has the highest environmental impact about 80%, 73% and 54% of total impact for GWP, AP and EP respectively Results indicated that by utilizing GHA, reduction of 10%, 9.1%, and 7.2% in GWP, AP, and EP impact values occurs respectively. Therefore, it is concluded that the use of groundnut husk ash in concrete will lessen the impact of carbon dioxide and other green house gases (GHG) on environment and adds to the sustainability aspect by utilizing waste.

Low quality and yield of methane severely hindered the industrial application of straw biogas fermentation and there has been no effective solution found so far. In this study, a novel method has been developed to improve the quality and yield of methane during biogas fermentation. We coupled microbial electrolysis cell (MEC) with normal anaerobic fermentation to enhance the yield and purity of methane. This novel fermentation process achieved the methane purity of more than 85%, which was critically higher than those of previously published reports. With the stimulation from microorganisms and electric current, the degradation of fiber has been greatly enhanced. The MEC system significantly improves the yield and purity of biogas, bringing a new path to synthesize the methane by the carbon dioxide and hydrogen ions in solution under the electron. Electrochemical index analysis showed the extra methane synthesis which was mainly led by the external circuit electron transfer. The result of the gas chromatograph and solid degradation rate showed that the carbon source of extra methane was CO2 produced in normal fermentation and extra volatile solid degradation. These results show that MEC significantly enhanced the quality and yield of methane in a straw fermentation process, giving insights for normal anaerobic fermentation.

Carbon dioxide capture by ammonia is considered one of the promising technologies for emission control in cement plants. This paper focuses on the experimental investigation of the factors affecting the chemical absorption process of carbon dioxide by ammonium hydroxide solution. The factors include ammonia concentration below 14%, reaction temperature below 20 °C and reaction time 30 min as the optimum parameters. The paper also highlights the economic and practical aspects to be taken into consideration when applying this technology to cement plants.

In this work, a biomethane fuel was obtained from biogas, using a solid matrix of ashes obtained from a central heating plant fed by wood. Biomethane composition was studied in an experimental pilot plant that treats organic waste through dry anaerobic digestion. European limits were considered and respected for the biomethane injection into the gas grid. The process was able to completely remove carbon dioxide (CO2) during its initial phase. After 50 h of test CO2 concentration started to appear in the outlet gas. This behaviour is related to the ash content, reactive phases (e.g., Ca hydroxides) and fine particle size (

It is traditional practice to treat acute hyperventilation (thought to be due to anxiety) by having patients rebreathe into a brown paper bag. The author reports three cases in which this treatment, erroneously applied to patients who were hypoxemic or had myocardial ischemia, resulted in death. This clinical experience motivated a study of the effects of paper bag rebreathing in normal volunteers. Subjects deliberately hyperventilated to an average end-tidal CO 2 concentration of 21.6 (SD, 3.2) mm Hg and then continued to hyperventilate into a no. 4 Kraft brown paper bag containing the calibrated sensors for a Hewlett-Packard 47210A capnograph and a Teledyne TED 60J digital oxygen monitor. Fourteen men and six women with an average age of 36 years (SD, 6.1) were tested. Results are reported as mm Hg. After 30 seconds of rebreathing, mean change in O 2 from room air was −15.9 (SD, 4.6) and mean CO 2 was 38.7 (SD, 6.2); at 60 seconds, −20.5 (6.0) and 40.2 (6.4); at 90 seconds −22 (6.8) and 40.5 (6.4); at 120 seconds −23.6 (6.8) and 40.7 (6.5); at 150 seconds −25.1 (1.2) and 41 (7.3); and at 180 seconds −26.6 (8.4) and 41.3 (7.5). A few subjects achieved CO 2 levels as high as 50, but many never reached 40. The mean maximal drop in O 2 was 26 (8.8); seven subjects had drops in oxygen of 26 mm Hg at three minutes, four had drops of 34 mm Hg, and one had a drop of 42 mm Hg. Three subjects rebreathed into an 18-L plastic bag filled with 100% O 2 , but although CO 2 rapidly exceeded 40, O 2 levels reached 21% within two to four minutes and continued to decline to less than 10% at 15 minutes. Paper bag rebreathing decreases inspired oxygen sufficiently to endanger hypoxic patients. Paper bag rebreathing should never be administered unless myocardial ischemia can be ruled out and the patient's oxygenation has been directly measured by arterial blood gases or pulse oximetry Since these conditions are impossible to achieve outside the hospital, its recommendation and use by prehospital personnel should be abandoned, and its use in hospital probably should be diminished.

Carbon dioxide and hydrogen sulfide are the main contaminants in biogas, which reduce its calorific value and cause wear on metallic appliances through corrosion. There are no comparative studies on the potential of dry adsorption and wet wood ash (carbonation) process on biogas upgrade. The current study for the first time investigates the effects of different process parameters on the use of wood ash for purification of biogas and compares the performance of the two processes. The chemical composition of wood ash was characterized using X-ray fluorescence (XRF) while biogas was analysed using gas chromatography and a digital biogas analyser. The effects of process parameters on biogas carbonation method were investigated. The highest CO2 uptake and methane increment achieved by use of wood ash slurry was 2.30 mmol/g-wood ash and 88%, respectively. This high CO2 uptake was possibly due to the high content of oxides (46% TS) in natural wood ash. The optimum conditions of adsorbent/water ratio and biogas flow rate for methane enhancement were 1:4, and 100 ml/min, respectively. In dry adsorption processes, an increase in mass of activated wood ash from 2.5 to 35 g increased CO2 removal from 8.9 to 67.9%. Furthermore, the evaluation of carbonation adsorption indicated that the process followed pseudo-first order kinetics. Activation of wood ash did not significantly improve its CO2 uptake by carbonation while the uptake by activated wood through dry adsorption was comparable to that of raw wood ash through carbonation process. Conclusively, raw wood ash by carbonation process is a good candidate recommendable for purifying biogas in household digesters.

The increasing rate of food waste (FW) generation globally, makes it an attractive resource for renewable energy through anaerobic digestion (AD). The biogas recovered from AD can be upgraded by the methanation of internally produced carbon dioxide, CO2 with externally sourced hydrogen gas, H2 (biomethanation). In this work, H2 was added to AD reactors processing FW in three successive phases, with digestate from preceding phases recycled in succession with the addition of fresh inoculum to enhance acclimation. The concentration of H2 was increased for succeeding phases: 5%, 10% and 15% of the reactor headspace in Phase 1 (EH1), Phase 2 (EH2) and Phase 3 (EH3), respectively. The H2 utilisation rate and biomethane yields increased as acclimation progressed from EH1 through EH3. Biomethane yield from the controls: EH1_Control, EH2_Control and EH3_Control were 417.6, 435.4 and 453.3 NmL-CH4/gVSadded accounting for 64.8, 73.9 and 77.8% of the biogas respectively. And the biomethane yield from the test reactors EH1_Test, EH2_Test and EH3_Test were 468.3, 483.6, and 499.0 NmL-CH4/gVSadded, accounting for 77.2, 78.1 and 81.0% of the biogas respectively. A progressive in-situ biomethanation could lead to biomethane production that meets higher fuel standards for gas-to-grid (GtG) injections and vehicle fuel – i.e. >95% CH4. This would increase the energy yield and carbon savings compared to conventional biogas upgrade methods. For example, biogas upgrade for GtG by in-situ biomethanation could yield 7.3 MWh/tFW energy and 1343 kg-CO2e carbon savings, which is better than physicochemical upgrade options (i.e., 4.6–4.8 MWh/tFW energy yield and 846–883 kg-CO2e carbon savings).

Artificial catalytic synthesis of ammonia has become a hot research frontier in recent years. It is regarded as a promising approach that may replace the Haber-Bosch process and reduce global carbon dioxide emission. However, it is extremely difficult for the cleavage of nitrogen molecules under ambient conditions. Thus the ammonia yield rate is still low and the study is still limited in lab scale. If nitrites or nitrates are used as nitrogen sources, rather than nitrogen gas, the catalytic efficiency can be significantly improved, and the residual nitrate and nitrite contaminations in water systems can be efficiently eliminated and converted to energy sources at the same time. It is an emerging alternative for artificial ammonia synthesis, while there is not enough focus on the reduction of nitrate and nitrite. Herein, we systematically compared the differences between the reduction of nitrogen and nitrates, as well as listed the challenges in this area. The total conversion rate and energy efficiency of catalytic nitrate reduction are much higher than nitrogen gas reduction due to the much higher solubility and better converting pathway, which might be further enhanced by employing catalysts improvement strategies. Further, we also proposed suitable materials as well as a few future researches needs that may help boost the development of artificial ammonia synthesis using nitrate.

The 2011–2016 reports from the Food and Agriculture Organization of the United Nations has stated that annual food loss and waste occurs on a massive scale in fisheries and aquaculture. This study aimed to explore advanced technologies to recycle wasted salmon as an industrial resource with high commercial value by applying enzymatic hydrolysis under HPCD. Our results showed that HPCD treatment at 50 °C and 1 MPa for 16 h effectively prevents salmon from microbial contamination. Real-time PCR analysis demonstrated that HPCD was also able to inhibit an increase in bacteria at moderate temperatures. Based on NGS analysis, there was a very low abundance of Bacillus and some histamine producers, such as Pseudomonas, Acinetobacter, Enterobacter, and Klebsiella, detected in samples treated using HPCD at 50 °C and 1 MPa for 16 h. Hydrolysate analysis showed that HPCD treatment at 1 MPa did not affect the hydrolysates from salmon. It is anticipated that the results from this study will support the application of HPCD in industrial enzymatic hydrolysis and increase the sustainability of bio-based materials.

The effect of substrate (food waste and cow dung) and inoculum (sludge solution) ratio on the hydrogen fermentation is experimentally investigated in this study. Five reactors are prepared using various ratios of substrate and inoculum on volume basis and the hydrogen (H2) and carbon dioxide (CO2) generation is observed for 15 days. Result revealed that variation in the ratio cause substantial effect on the fermentation process. The reactor with substrate to inoculum ratio of 1:3 showed maximum hydrogen concentration (19.73%) in the produced biogas. The cumulative hydrogen yield is increased with the ratio and the highest value (114.4 mL/g total solid) is obtained with the ratio 1:3. The carbon dioxide concentration showed the least value in 1:3 ratio indicating the maximum conversion of the feedstock to hydrogen compared to the other samples. The result suggested that proper substrate to inoculum ratio is the deciding factor to improve the fermentation process. A ratio of food waste and cow dung with sludge solution (1:3) appeared the best combination for enhanced co-digestion process.

In this study, numerical analysis for downdraft gasifier was performed. The influence of operational parameters such as temperature and equivalence ratio on the composition of producer gas was investigated. The range of temperature was from 750 K to 1150 K with an equivalence ratio of 0.2 to 0.67 were considered for this study. Moisture content of 12% and 7% was identified for Neem leaves and Asoka leaves, respectively. The main gas constituent of producer gas formed during biomass gasification in downdraft gasifier was hydrogen (H2), carbon monoxide (CO), methane (CH4), steam (H2O), carbon dioxide (CO2), and nitrogen (N2).

Microalgae is one of the most important sources of green hydrocarbons and it is likely to reduce dependence on fossil fuels due to the high percentage fats of microalgae, and also has a rapid growth rate and consumes the carbon dioxide in large quantities. Besides, the cultivation of microalgae does not require arable land. This short review aims to explain the suitability of microalgae as a biofuel source depending on the content of lipids, and catalytic chemical processes to convert the crude oil of microalgae into biofuels by using different types of modified HZSM-5 zeolites. Also, this review sheds light on the different methods to modify HZSM-5 zeolite toward enhancing the selectivity of cracking and deoxygenation processes by using modified HZSM-5 zeolite with rare earth metals.

Natrium Hydroxide (NaOH) and Calcium Hydroxide (Ca(OH)2) as an absorbent was used in the filtration system of the mobile anaerobic digester (AD) to improve the quality of biogas from dairy cattle manure. Twelve pilots insulated of mobile AD used in this study. The average temperature inside the digester was 28.37 °C, and in the outer digester 27.16 °C. The average biogas temperature before filtration was 28.37 °C, and after filtration 31.09 °C. The biogas filtration using adsorbent was a very significantly effect (P 0.05). The average biogas production using NaOH was 717.50 mL h−1, Ca(OH)2 715.63 mL h−1, and control 676.25 mL h−1. The adsorbent treatments were very significantly effects (P 0.05) among the type of adsorbent. The NaOH could increase the percentage of methane (CH4) (14.26 %) and oxygen (O2) (22.06 %) content, and reduced carbon dioxide (CO2) (30.86 %) compared with control. However, Ca(OH)2 adsorbent could increase CH4 (7.77 %) and O2(11.22 %) and reduced CO2 (17.88 %). The mobile anaerobic digester is suitable for smallholder farmer because more simple and cheaper.

Microalgal biomass offers high biomass productivity, high photosynthetic efficiency, and low land requirement. However, there are challenges for the sustainable conversion of microalgae-to-biofuels. Through torrefaction, microalgal biomass can be upgraded to enhance its biomass characteristics. A life cycle assessment (LCA) is proposed to evaluate the environmental impact of the production of torrefied microalgal biomass (TMB). Using LCA, four different conversion pathways of generating TMB are considered and compared. The four scenarios include the effect of scaling-up the production to pilot-scale and comparing two cultivation systems (open pond and the photobioreactor). The analysis includes the influence of the torrefaction severity index (TSI) on environmental impacts. The results have shown that TSI is directly related to the global warming potential (GWP) wherein the influence of torrefaction temperature to the GWP was higher compared to the duration. The impact of the cultivation system was relatively higher compared to the other processes due to its high energy requirement. The scale-up effect of the cultivation phase resulted in a reduction of the GWP by 128% and 91% for the open pond and the photobioreactor, respectively. A net negative GWP impact is achieved in a pilot-scale with the use of an open pond cultivation system. With this configuration, the uptake of carbon dioxide during the cultivation outweighs the GWP impacts of producing TMB. Furthermore, the negative GWP result is lower compared with the results of previous studies on torrefaction and pyrolysis.

Residues of leek, cabbage and cauliflower from the market places as representatives of lignocellulosic biomass were processed via hydrothermal gasification to produce energy fuel. The experiments were carried out in a batch reactor at temperatures 300, 400, 500 and 600 degrees C and corresponding pressures varying in the range of 7.5-43 MPa. Natural mineral additives trona, dolomite and borax were used as homogenous catalysts to determine their effects on the gasification. More than 70 wt% of carbon in vegetable residue samples were detected in the gas phase after the hydrothermal gasification process at 600 degrees C. The addition of trona mineral further promoted the gasification reactions and as a result, less than 5 wt% carbon remained in the solid residue at the same temperature, degrading the biomass samples into gas and liquid products. The fuel gas with the highest calorific value was recorded to be 25.6 MJ/Nm(3), from the hydrothermal gasification of cabbage at 600 degrees C, when dolomite was used as the ho-mogeneous catalyst. The liquid products obtained in the aqueous phase were detected as organic acids, aldehydes, ketones, furfurals and phenols. The gas products were consisted of hydrogen, carbon dioxide, methane, and as minors; carbon monoxide and low molecular weight hydrocarbons (ethane, propane, etc.). Above 500 degrees C, all biomass samples yielded 50-55 vol% of CH4 and H-2 while the CO2 composition was around 40 vol% as the gas product. (C) 2020 Energy Institute. Published by Elsevier Ltd. All rights reserved., Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [106T748]; Ege University-EBILTEMEge University [2008BIL017], We sincerely appreciate and give thanks for the financial support of The Scientific and Technological Research Council of Turkey (TUBITAK) (Project No: 106T748) and Ege University-EBILTEM (Project No: 2008BIL017). We also thank Mr. G. Serin for his support in the pre-treatment of the biomasses and his help during the experimental study.

This project study involves the techno-economic assessment of two new advanced configurations for amine-based carbon dioxide capture from a pulp mill. The newly proposed advanced configurations include advanced rich amine four split (ARA4S), and advanced rich amine three split with desorber inter-heating (ARA3S-DI) which is aimed at reducing carbon capture cost and carbon emissions. The rate-based model in ProMax® 4.0 was used for the simulation study while the flue gas was provided by a 365,000 air dry tonne of pulp (ADt Pulp) per annum pulp mill in British Columbia, Canada. Comparative analysis revealed that the Capture Cost (US$/tCO2 and US$/ADt Pulp) of the 5 kmol/m3 MEA system was lowest for the conventional configuration, while for the 2 kmol/m3 AMP-3 kmol/m3 MEA blend it was lowest for the advanced rich amine 3-split with desorber inter-heating configuration. In addition, the Capture Costs of the MEA solution with a conventional configuration system is 8.7% higher than the AMP-MEA blend with advanced rich amine three split with desorber inter-heating configuration. Sensitivity analysis revealed that the combined effect of a carbon tax (US$ 40/tCO2), CO2 sales price (US$ 40/tCO2) and advanced configuration only led to a slight increase (2.6% for MEA and 2.1% for AMP-MEA blend) in the price of the northern bleached softwood kraft pulp. With an even better-performing solvent system and process configuration, the price of NBSK pulp may not be affected given the indicated CO2 tax and CO2 price regime.

There is a growing interest in the usage of hydrogen as an environmentally cleaner form of energy for end users. However, hydrogen does not occur naturally and needs to be produced through energy intensive processes, such as steam reformation. In order to be truly renewable, hydrogen must be produced through processes that do not lead to direct or indirect carbon dioxide emissions. Dry reformation of methane is a route that consumes carbon dioxide to produce hydrogen. This work describes the production of hydrogen from biomass via anaerobic digestion of waste biomass and dry reformation of biogas. This process consumes carbon dioxide instead of releasing it and uses only renewable feed materials for hydrogen production. An end-to-end simulation of this process is developed primarily using Aspen HYSYS® and consists of steady state models for anaerobic digestion of biomass, dry reformation of biogas in a fixed-bed catalytic reactor containing Ni–Co/Al2O3 catalyst, and a custom-model for hydrogen separation using a hollow fibre membrane separator. A mixture-process variable design is used to simultaneously optimize feed composition and process conditions for the process. It is identified that if biogas containing 52 mol% methane, 38 mol% carbon dioxide, and 10 mol% water (or steam) is used for hydrogen production by dry reformation at a temperature of 837.5 °C and a pressure of 101.3 kPa; optimal values of 89.9% methane conversion, 99.99% carbon dioxide conversion and hydrogen selectivity 1.21 can be obtained.

Anaerobic co-digestion of food waste, cow dung, and sludge solution is experimented in the presence of calcium peroxide (CaO2) as the catalyst to produce hydrogen and methane as a source of renewable energy. The substrate to inoculum ratios (v/v) of 1:1(S1), 1:2(S2), 1:3(S3), 1:4(S4) and 1:5(S5) are investigated in separate fermentative and methanogenic reactors. The result from the fermentative reactors indicate maximum hydrogen concentration of 26.34% with cumulative yield of 114.1 mL/g total solid (TS) in S3 compared to the other samples. Methanogenic reaction shows the highest methane concentration of 54.13% in S3. The highest daily (average) and cumulative biogas yield of 5.36 mL/g TS and 201.9 mL/g TS respectively are identified in S3. A maximum carbon dioxide concentration of 63.11% is found in S1. Overall, the substrate to inoculum ratio of 1:3 is spotted to be optimal for effective hydrogen and methane production during the anaerobic co-digestion process.

Chemical manufacturing involves carbon sources releasing CO2 into the atmosphere. By contrast, seaweeds are carbon sinks that can absorb released CO2 and therefore have great potential for use as feedstocks in sustainable chemical manufacturing. In particular, seaweeds could contribute to mitigating vast amounts of global CO2 emissions. Accordingly, seaweeds could be an excellent candidate biomaterial for sustainable production of hydroxymethylfurfural (HMF), called a 'sleeping giant' platform chemical due to its wide versatility in chemical manufacturing. HMF is produced through sugar dehydration mechanisms, and seaweed storage glucans comprised of glucose can be appropriate feeding substrates for its production. This opinion article introduces a new opportunity for sustainable production of HMF using storage glucan-rich seaweeds.

International audience; A bioreactor was designed to provide high gas mass transfer to reach cell and product titres in the g L-1 level from CO2 for realistic, laboratory scale, engineered autotrophic strain evaluation. The design was based on independent CO2, H-2 and air inputs and the ability to operate at high pressures. The bioreactor configuration and cultivation strategy enabled growth of Cupriavidus necator strains for long periods, to reach over 3 g L-1 dry cell weight. No negative impact of the high pressure was observed on viability of the strains up to more than 4 bar overpressure. The cultivation was then carried out using an engineered isopropanol producing strain; in this case, 3.5 g L-1 isopropanol was obtained from CO2 as the sole carbon source. This is the first reported demonstration of a successful production from engineered bacteria of product in the g L-1 range on CO2 , raising the prospect of future development of CO2-based bioprocesses.

A fundamental investigation was conducted on the combustion characteristics of pulverized torrefied biomass particles both in air and in simulated oxy-combustion gases, containing oxygen and carbon dioxide. Power generation by oxy-combustion of renewable biomass, coupled with carbon-dioxide capture and utilization or sequestration, can contribute to a reduction of the atmospheric concentration of carbon dioxide. This is because renewable biomass absorbs carbon dioxide during its growth, but this method will potentially release almost none to the atmosphere. The goal of this research is to determine the minimum oxygen mole fraction in the furnace input gases, which still induces single particle combustion characteristics that are similar to those encountered in air. Torrefied biomass types were herbaceous, waste crop, and woody. Entire luminous combustion profiles of single particles, burning in a drop-tube furnace, were recorded pyrometrically and cinematographically from ignition to extinction. Combustion took place in two phases: volatiles evolved and burned in spherical envelope flames and, upon extinction of these flames, the residual chars ignited and burned. Replacing the air background gas with 21%O2/79%CO2 prolonged the ignition delay and the burnout time of biomass particles and reduced their temperature. To the contrary, further increasing the oxygen mole fraction in CO2 to 30% caused opposite trends. For each biomass type, the oxygen fraction in CO2 that would produce combustion temperature and time parameters most similar to those of air combustion was projected to be between those two oxygen concentrations (21–30%), and this was verified experimentally. An empirical correlation was formulated to make initial estimates of oxy-combustion concentrations needed for each fuel based on their physical and chemical properties. Reduction of the amount of oxygen in oxy-combustion is important to curtail the energy penalty inflicted by the operation of the air separation unit.

The effect of using an additive based on alumina nanoparticles and oleic acid to reduce the environmentally harmful gas emissions from biodiesel and its blends in diesel. Of all this, the physic-chemical properties of the blended fuels were calculated with the help of correlations of colloidal particles and blending rules, setting additive levels of 10, 20, and 50 ppm. The results showed decreases in emissions of sulfur dioxide and particulate matter, respectively, whereas carbon dioxide emissions recorded no significant improvement but any changes in actual fuel efficiency. For nitrogen dioxide emissions, an increase was observed with the implementation of the specific concentrations of nanoadditives; these were illustrated by improvements in the delay of the ignition times, which would be appropriate for proper operation of the engine.

The Petroleum resources are depleting rapidly. Biodiesel is one of the most favourable alternatives for Fossil Fuels. Vegetable oils are coming from agricultural sources. Hence CO2 emission in the environment can be reduced when compared to petroleum products. In this investigation Jujube Methyl Ester is prepared by transesterification method using Potassium hydroxide (KOH) as catalyst. It is used in Four Stroke, single cylinder variable comparison engine (VCR). The rated speed of the engine is 1500 rpm at different loads. The engine performance was analyzed for different nozzle and blends. Nitric oxide (NOx) and Particular matter (PM) are slightly increased. Carbon dioxide (CO2) is apparently increases with load whereas HC is found to be decreasing with load. Carbon monoxide (CO) emission is high for this.

The thermochemical conversion may be an alternative for the final destination of poultry litter wastes. In this study, the effect of calcined eggshell (CE) and calcined dolomite (CD) on slow pyrolysis and air gasification performance of poultry litter waste was evaluated. The catalysts (CE and CD) presented potential for use in the in situ capture of the carbon dioxide produced in the pyrolysis process. In relation to the gasification tests, it can be concluded that both catalysts were effective in cracking the produced tar. Reductions in gas tar concentration of 25.47 and 54.32% were observed for CE and CD, respectively. The catalysts are effective at cracking light hydrocarbons (

Massive industrialization all over the globe is the main cause for the generation of huge quantity of wastes such as flue gas and wastewaters. Mindless release of these hazardous wastes into the environment is threatening the health and survival of the mankind. Judicious use of these wastes for microalgal biomass cultivation is recognized as a plausible approach for the creation of a renewable and sustainable process chain for biofuel production. This study was designed to cultivate microalgae utilizing the organic and inorganic nutrients from the industrial wastewater (IWW) and coal-fired flue gas (FG) for simultaneous waste bio-remediation and biomass production for biorefinery application in closed photobioreactors. The two microalgae, Chlorella sp. and Chlorococcum sp. were cultivated in industrial wastewater where varying concentrations of coal-fired FG from 1 to 10% CO2, volume/volume percent (v/v) was supplied to stimulate the mixotrophic growth. Performance of the two microalgae was evaluated in terms of nutrient removal (ammonium, nitrate, phosphate and COD), CO2 fixation, total lipid and carbohydrate content obtained in the integrated mode of process development. The IWW with flue gas (5% CO2 (v/v)) resulted in maximum growth and CO2 fixation. The highest biomass growth (1.52 g L−1) and CO2 fixation (187.65 mg L−1 d−1) of Chlorella sp. with nutrient removal of >70% was observed by 5th day of batch cultivation. Nearly 90% removal of nitrogen resulted in nutrient limitation condition that steered the accumulation of lipid (17–34%) and carbohydrate (21.5–23.1%) in Chlorella and Chlorococcum sp. An overall 1.7 fold improvement in biomass was observed in this process integration compared with control culture. The present study presents a green process for waste remediation, CO2 fixation and production of biomass rich in lipid & carbohydrate content for the development of a green microalgal biorefinery.

One of the main goals of the green chemistry is to develop sustainable and less hazardous chemical processes and products. Dimethyl carbonate (DMC) is attracting attention due to the wide variety of applications and the possibility of producing it from carbon dioxide. In this work, the DMC production process via urea has been optimized. Two main sections can be distinguished: the synthesis of urea and the production of DMC. An equation based approach is used to model the system. The DMC production from renewable ammonia/methanol/CO2 presents a promising production cost, around 520 €/t. The production of urea alone has also been evaluated in this work. A sensitivity analysis is carried out showing the influence of the methanol price in the DMC cost and the ammonia price in the urea cost. A simplified sustainability index is used to evaluate the environmental performance of urea/DMC production.

CO2 capture is necessary to decarbonize natural gas combined cycles (NGCC) that will be used to provide power when renewable power is unavailable. The PZAS™ (Piperazine (PZ) with the Advanced Stripper) second generation capture technology has been successfully tested with coal-fired flue gas. This paper reports reliable testing of PZAS at NGCC conditions for 2000 hours in a 0.66 m ID absorber at the National Carbon Capture Center (NCCC). Coal-fired flue gas diluted with air entered the absorber at 77 oC. 5 m PZ was regenerated by the Advanced Stripper with 2.45 gJ steam/tonne CO2 at 6.2 bara. With 40 feet of packing and pump-around intercooling the absorber provided 90–95% CO¬2¬ removal with a rich loading of 0.40–0.41 mol CO2/mol N. The apparent rate of PZ oxidation was 0.3 kg/tonne CO2. The water wash reduced PZ emission to less than 1 ppm. In the last 400 hours of testing, carbon treating clarified the solvent color, reduced ammonia production by as much as 40%, and improved both absorber and stripper performance. Testing with coupons showed that 304 SS had an acceptable corrosion rate even at the severe conditions of the stripper at 150 oC.

Membrane technologies have received much attention in microalgae biorefinery for nutrients removal from wastewater, carbon dioxide abatement from the air as well as the production of value-added products and biofuel in recent years. This paper provides a state-of-the-art review on membrane fouling issues and its control in membrane photobioreactors (MPBRs) and other algal-related membrane processes (harvesting, dewatering, and biofuel production). The mechanisms of membrane fouling and factors affecting membrane fouling in algal-related membrane processes are systematically reviewed. Also, strategies to control membrane fouling in algal-related membrane processes are summarized and discussed. Finally, the gaps, challenges, and opportunities in membrane fouling control in algal-related membrane technologies are identified and discussed.