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Effectivity–ecosphere–economics in nZEB retrofit procedures
2019
Ryńska, Elżbieta | Koźmińska, Urszula | Rucińska, Joanna
Sustainable development has by now become an element deeply integrated in the everyday design. It has many shades and may be found under many names. We speak about resiliency in design and procurement of passive, ecologic, plus energy, or nZEB buildings. Nevertheless, if we look closely, we may distinguish certain characteristic ideas. First, sustainable development of societies and urbanization processes should be consistent on a deeper level than presently, and be included within design processes, organization, and planning, as well as modernization and redevelopment procedures of existing urban tissue. Secondly, urbanization should be perceived holistically, as an interaction and harmonious development of both natural and manmade environments, with solutions based on the best technical and technological standards available. Lastly, described ideas are achievable only, if we include continuous cooperation between urban planners, architects, specialist consultants, as well as energy-efficient interdisciplinary solutions to achieve high standard energy measures. One of the thresholds is economic feasibility; the other is health and well-being of the users which should always be discussed as a priority. This paper—outside a brief theoretical approach to initial procedures in design management—will dwell on transformation and modernization of an existing building belonging to the Warsaw University of Technology, one of the oldest universities in Poland, its founding dating back to the beginning of the twentieth century. In 2015, a Nordic Finance Mechanism grant dedicated to the nZEB technology transfer from Norway to Poland was awarded to a group of researchers from Warsaw University of Technology and NTNU Trondheim. The main aim of the project is implementation of nZEB knowledge in Poland, as well as preparation of two integrated concept designs for public (University) buildings as exemplary case studies which could act as the benchmarks for other public buildings.
显示更多 [+] 显示较少 [-]Selection of Agricultural Straws as Sustained-Release Carbon Source for Denitrification in a Drawer-Type Biological Filter
2019
Guan, Xiangxiong | Ji, Guixia | Xu, Suyun | Yun, Yunbo | Liu, Hongbo
The aim of this paper is to select feasible agricultural straws as high-quality sustained-release carbon source and examine the effect of determined agricultural organic waste on improving denitrification efficiency. Five kinds of agricultural straws, i.e., the rice straw, the corn straw, the wheat straw, the broomcorn straw, and the reed straw, were evaluated in a self-designed drawer-type biological filter. Results showed that the contents of C, H, and N in the five straws were 34.0~41.0%, 4.9~5.4%, and 1.1~1.5% respectively. The highest TOC release capacity of the rice straw was 12.4 ± 1.3 mg g⁻¹ and the average TOC release of other waste straws ranged from 6.0 to 9.2 mg g⁻¹. The TN release capacities of all the five straws were at a low level, ranging from 0.2 to 1.4 mg g⁻¹. Preliminary denitrification studies showed that the corn and the rice straw could be used as high-quality carbon sources, achieving a COD removal rate of 47.3~50.2% and a TN removal rate of 21.8~24.8% for wastewater with low C/N ratio. The rice straw and the corn straw founctioned both as favorable solid carbon sources and biofilm carriers; the carbon source quality of the corn straw lixivium is more beneficial to microbial utilization. The drawer-type biological filter has showed a good efficiency of denitrification for nitrogen removal when using agricultural straws as biofilm carriers.
显示更多 [+] 显示较少 [-]S-incorporated TiO2 coatings grown by plasma electrolytic oxidation for reduction of Cr(VI)-EDTA with sunlight
2019
Gordillo-Delgado, Fernando | Moya-Betancourt, Sara | Parra-López, Anyi | Garcia-Giraldo, John A. | Torres-Cerón, Darwin
The plasma electrolytic oxidation (PEO) technique was used to prepare photocatalytic S-TiO₂ coatings on Ti sheets; the incorporation of the S ions was possible from the electrolyte for modifying the structural and optics characteristics of the material. In this work, substrates of Ti (ASME SB-265 of 20 × 20 × 1 mm) were used in a PEO process in 10 min, using constant voltage pulses of 340 V with frequency of 1 kHz and duty cycles of 10% and of 30%. Solutions with H₂SO₄ (0.1 M) and CH₄N₂S (52 and 79 mM) were used as electrolytes. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy (EDS) were utilized to analyze the surface morphology, crystalline phase, and chemical composition of the samples. According to the results, the catalyst coatings had microporous structure and contained anatase-rutile TiO₂ nanocrystalline mixture, until 73.2% rutile and 26.8% anatase in the samples grown with 30% duty cycle and the lowest concentration of CH₄N₂S. From the EDS measurements, the incorporation of sulfur ions to the coatings was 0.08 wt%. 99.5% reduction efficiency of Cr(VI)-EDTA with sunlight was observed after 2 h; it was determined by diphenyl carbazide spectrophotometric method. These coatings have potential for effective sunlight heterogeneous photoreduction of this toxic, cumulative, and non-biodegradable heavy metal that contaminates the soil and water and is a serious risk to sustainability, ecosystems, and human health.
显示更多 [+] 显示较少 [-]Natural Sawdust as Adsorbent for the Eriochrome Black T Dye Removal from Aqueous Solution
2019
Akhouairi, Siham | Ouachtak, Hassan | Addi, Abdelaziz Ait | Jada, Amane | Douch, Jamaa
This paper deals with the adsorption of an anionic dye, Eriochrome Black T (EBT), from aqueous solutions onto sawdust, which is a natural, eco-friendly, widespread, and a low-cost bio sorbent. The aim of the work is to append values to the wood industry waste. Thus, sawdust was used as adsorbent in both batch reactor (BR) and fixed bed column (FBC), and various operating parameters influencing the adsorption process were investigated. The kinetic and the equilibrium adsorption results were found to agree with, respectively, the prediction of the pseudo-second-order equation and the Langmuir model. This latter allowed also the determination of the maximum EBT dye adsorbed amount, which was found to be about 40.96 mg EBT per gram of sawdust at pH = 4, corresponding to % dye removal of about 80%. In addition, the influence of various parameters on the dye adsorption, such as the adsorbent dose, the aqueous phase pH, and the initial dye concentration, was also examined. In batch experiments, The EBT adsorbed amount was found to increase either by increasing the amount of sawdust or by decreasing the aqueous phase pH, whereas, in the fixed bed column, the EBT retention was found to increase by decreasing the flow rate of the dye through the column. The overall data indicate that the EBT adsorption is mainly governed by the electrostatic interactions occurring between the adsorbent material and the dye.
显示更多 [+] 显示较少 [-]Cd(II) Removal by Novel Fabricated Ground Calcium Carbonate/Nano-TiO2 (GCC/TiO2) Composite from Aqueous Solution
2019
Wang, Shanguang | Zhou, Dali | Zhou, Jiabei | Liu, Can | Xiao, Xiao | Song, Chengsheng
The heavy metal Cd(II) in wastewater is highly toxic to organisms and must be removed. In this work, an efficient Cd(II) adsorbent consisting of ground calcium carbonate (GCC) and nano-TiO₂ (GCC/TiO₂) was harvested through a facile two-step strategy. Firstly, GCC was immersed in titanium sol which prepared from titanium butoxide to form the precursor. Secondly, GCC/TiO₂ was obtained via hydrothermal reaction and the optimal hydrothermal condition was determined to be pH of 3, temperature of 200 °C and reaction time of 12 h. The removal of Cd(II) from aqueous solution by adsorbents under different hydrothermal conditions and adsorption experiments was studied by means of SEM, FT-IR, XPS, and ICP. The maximum Cd(II) removal capacity was approximately 124.07 mg/g at 25 °C and the adsorption equilibrium was attained in only 8 min (at 100 mg/g initial Cd(II) concentration, 0.8 g/L adsorbent dosage, and an initial Cd(II) solution pH of 5). Furthermore, the Cd(II) removal capacity of GCC/TiO₂ was significantly higher than that of isolated GCC and TiO₂ and exhibited an excellent self-settlement property, which is beneficial for adsorbent separation in practical applications. The Cd(II) removal mechanisms include ion-exchange reaction between Cd(II) and the Ca²⁺ ions on the GCC/TiO₂ surface and electrostatic attraction. Moreover, the GCC/TiO₂ adsorbent could be regenerated by ethylenediaminetetraacetic acid disodium salt and exhibited a high reusability. The adsorption data could be well fitted by the Langmuir model, and the adsorption kinetic follows the pseudo-second-order model indicating that the removal processes are controlled by the chemisorption mechanism.
显示更多 [+] 显示较少 [-]Extracellular electron transfer modes and rate-limiting steps in denitrifying biocathodes
2019
Wang, Ke | Zhang, Shaohui
Denitrifying bioelectrochemical system provided an alternative technology for nitrogen removal, even power recovery from wastewater, and its nitrogen removal performance and intermediate accumulation were affected by the extracellular electron transfer modes and rate-limiting steps in denitrifying biocathodes. In the current study, the extracellular electron transfer modes and rate-limiting steps for nitrate reduction and nitrite reduction of denitrifying biocathode were investigated through cyclic voltammetry. When the cathode potential swept from 0.003 to − 0.897 V (vs. Ag/AgCl), denitrifiers were indispensable for electrochemical denitrification. Three peak potentials were found in the cyclic voltammogram of denitrifying biocathode, where E₁ (− 0.471 to − 0.465 V) and E₂ (− 0.412 to − 0.428 V) represented respectively nitrate reduction and nitrite oxidation while E₃ (− 0.822 to − 0.826 V) represented nitrite reduction. Nitrate reduction involved the direct electron transfer mode while nitrite reduction involved the mediated electron transfer mode. Intracellular catalytic reaction was the rate-limiting step for nitrate reduction, independent on the electrochemical activity of denitrifying biocathode and the nitrate supply. The nitrate supply posed an effect on the rate-limiting step for nitrite reduction. The mediator transfer was the rate-limiting step for nitrite reduction in the absence of nitrate. But both mediator transfer and intracellular catalytic reaction became the rate-limiting steps for nitrite reduction in the presence of sufficient nitrate.
显示更多 [+] 显示较少 [-]Reduced ecotoxicity and improved biodegradability of cationic biocides based on ester-functionalized pyridinium ionic liquids
2019
Trush, Maria | Metelytsia, Larysa | Semenyuta, Ivan | Kalashnikova, Larysa | Papeykin, Oleksiy | Venger, Irina | Tarasyuk, Oksana | Bodachivska, Larysa | Blagodatnyi, Volodymyr | Rogalsky, Sergiy
Ester-functionalized pyridinium ionic liquids (ILs), 1-decyloxycarbonylmethylpyridinium chloride (PyrСOOC₁₀-Cl), and 1-dodecyloxycarbonylmethylpyridinium chloride (PyrСOOC₁₂-Cl) have been synthesized and studied for their environmental toxicity. Simple long-chain pyridinium ILs, 1-dodecylpyridinium chloride (PyrC₁₂-Cl), and commercial disinfectant cetylpyridinium chloride (CPC) were used as reference compounds. Both ester-functionalized ILs and CPC showed significantly reduced antibacterial activity compared to PyrC₁₂-Cl. However, ester-functionalized ILs were found to have excellent antifungal activity towards Candida albicans fungus strains, similar to PyrC₁₂-Cl and much higher than for CPC. The molecular docking of ILs in the active site of the known antifungal target N-myristoyltransferase (Nmt) C. albicans has been conducted. The obtained results indicate the possibility of ILs binding into the Nmt pocket. The high stability of the complexes, especially for PyrCOOC₁₀-Cl, is ensured by hydrogen bonding, electrostatic anion-pi interactions, as well as hydrophobic pi-alkyl and alkyl interactions that was confirmed by calculated binding energy values. The acute toxicity studies of ester-functionalized ILs on D. rerio (zebrafish) hydrobiont have shown their dramatically reduced ecotoxicity compared to PyrC₁₂-Cl and CPC. Thus, LD₅₀ values of 15.2 mg/L and 16.8 mg/L were obtained for PyrCOOC₁₀-Cl and PyrCOOC₁₂-Cl, respectively, whereas CPC had LD₅₀ value of 0.018 mg/L. The primary biodegradation test CEC L-33-A93 of ILs indicated an improved biodegradability of ester-functionalized compounds compared to simple long-chain ILs. Based on the obtained results, PyrCOOC₁₀-Cl may be considered as very promising cationic biocide due to the combination of soft antimicrobial activity and reduced ecotoxicity, as well as improved biodegradability.
显示更多 [+] 显示较少 [-]Towards visible-light photocatalysis for environmental applications: band-gap engineering versus photons absorption—a review
2019
Marcelino, Rafaela B. P. | Amorim, Camila C.
A range of different studies has been performed in order to design and develop photocatalysts that work efficiently under visible (and near-infrared) irradiation as well as to improve photons absorption with improved reactor design. While there is consensus on the importance of photocatalysis for environmental applications and the necessity to utilized solar irradiation (or visible-light) as driving force for these processes, it is not yet clear how to get there. Discussion on the future steps towards visible-light photocatalysis for environmental application is of great interest to scientific and industrial communities and the present paper reviews and discusses the two main approaches, band-gap engineering for efficient solar-activated catalysts and reactor designs for improved photons absorption. Common misconceptions and drawbacks of each technology are also examined together with insights for future progress.
显示更多 [+] 显示较少 [-]Multiple lines of evidence of sediment quality in an urban Marine Protected Area (Xixová-Japuí State Park, SP, Brazil)
2019
Moreira, Lucas Buruaem | de Camargo, Júlia Beatriz Duarte Alves | Belletato Marques, Bruna | Martins, César C. | de Souza Abessa, Denis Moledo
Marine Protected Areas (MPAs) aim to protect habitats, biodiversity, and ecological processes as a conservation tool. These areas have been affected by contamination, which threats the biodiversity and ecological functioning. In this study, we evaluated the sediment quality of Xixová-Japuí State Park (XJSP), an MPA located in an urbanized Bay (Santos, Southeast Brazil) by integrating multiple lines-of-evidence. Six sites were selected within the XJSP and analyzed for sediment chemistry, toxicity, and benthic community descriptors using Sediment Quality Triad approach (SQT). Whole-sediment Toxicity Identification Evaluation (TIE) was employed as a complementary line of evidence to confirm the presence of domestic effluent discharges as a potential stressor. The SQT showed that sediments collected within XJSP are impacted by contaminants, exhibiting chronic toxicity and changes in benthic community. TIE results indicated that trace metals, organic contaminants, and ammonia contributed to the observed effects. Our results also indicate a lack of effectiveness of MPA in protecting the biodiversity due to the contamination sources, which requires efforts to pollution control in order to ensure the environmental conservation and management plan goals.
显示更多 [+] 显示较少 [-]Synthesis of novel waste batteries-sawdust-based adsorbent via a two-stage activation method for Pb2+ removal
2019
Niu, Zhirui | Zhang, Shaokang | Ma, Mengfan | Wang, Zhenyang | Zhao, Hanyang | Wang, Yingying
The novel waste alkaline battery-sawdust-based adsorbents (WABAs) are prepared by a two-stage activation method with the negative electrode materials as activator and different doping ratio of the positive electrode materials and pine sawdust as raw materials. The characteristics of the WABAs are analyzed by SEM, XRD, FT-IR, and specific surface determination (SBET). The Pb²⁺ adsorption properties of the WABAs are studied by changing the pH of solution, contact time, initial concentration, and temperature. It turns out that when the doping mass ratio is 1:4, the optimum performance of the WABAs is obtained, and comparing with the samples prepared by pure biomass, the iodine adsorption value, total acid groups, and cation exchange capacity (CEC) separately increased by 13, 106, and 22%, respectively. Kinetic studies show that the pseudo-second-order model is more suitable for describing the Pb²⁺ adsorption process and the Langmuir isotherm provides better fitting to the equilibrium data. The thermodynamic parameters indicate the adsorption process would be spontaneous and endothermic. Besides, the prepared WABAs could be reused for 5 cycles with high removal efficiency. This study provides an alternative route for waste alkaline battery treatment. Graphical abstract The schematic diagram of synthesis of waste batteries-sawdust-based adsorbent via a two-stage activation method for Pb²⁺ removal
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