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Direct Z-scheme La1-xCexMnO3 catalyst for photothermal degradation of toluene Full text
2019
Tang, Yiran | Tao, Yuwei | Zhou, Ting | Yang, Baozhu | Wang, Qing | Zhu, Zerui | Xie, Aijuan | Luo, Shiping | Yao, Chao | Li, Xiazhang
A series of Ce-doped LaMnO₃ (La₁₋ₓCeₓMnO₃) were prepared and were tested for gaseous toluene oxidation in order to investigate the effect of cerium doping in LaMnO₃ on activity under photothermal conditions. It was found that the activity and CO₂ yield of the catalyst can be effectively increased when x = 0.25. A group of characterization is used to characterize the morphology, composition, and physical properties of the as-prepared catalysts. Results show that the Ce-doped LaMnO₃ can form coexistence of La₁₋ₓCeₓMnO₃ and CeO₂, the reaction of CeO₂/La₁₋ₓCeₓMnO₃ under photothermal conditions follows the Mars-van Krevelen redox cycle mechanism, and the prepared CeO₂/La₁₋ₓCeₓMnO₃ can form a highly efficient Z-scheme heterojunction, which can enhance the electrons transfer speed of the catalyst. Moreover, in the photothermal catalytic degradation, lattice oxygen is the most important active substance, a small amount of cerium doping can increase the lattice oxygen content of perovskite and increase the activity of the reaction.
Show more [+] Less [-]Indoor formaldehyde removal by three species of Chlorphytum Comosum under the long-term dynamic fumigation system Full text
2019
Li, Jian | Zhong, Jiaochan | Zhan, Ting | Liu, Qinghui | Yan, Liushui | Lu, Mingming
Gaseous formaldehyde removal efficiency and physiological characteristics of leaves were investigated through a dynamic fumigation system. Three different species of potted Chlorophytum Comosum, (Green Chlorophytum Comosum for its green leaves), CC (Combined the leaves of Chlorophytum Comosum with leaves half green and half white) and PC (Purple Chlorophytum Comosum for its purple leaves), were exposed to formaldehyde for 7 days. The results showed formaldehyde removal efficiencies in the daytime were 71.07% ± 0.23, 84.66% ± 0.19, and 46.73% ± 0.15 at 1 ppm for GC, CC, and GC plants, respectively, and were 36.21% ± 0.24, 62.15% ± 0.19, and 34.97% ± 0.11 at night. This might be due to higher plant physiological activities (e.g., photosynthesis, respiration, and transpiration) during the daytime than at night. Ten physiological indicators of leaves were chosen to evaluate the 7-day fumigation process, which were chlorophyll, free protein, relative conductivity, malondialdehyde (MDA), hydrogen peroxide (H₂O₂), hydroxyl radical, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and total antioxidant capacity (T-AOC). Eight of these indicators increased, while chlorophyll decreased by 22.16%, 6.95%, and 25.32%, and CAT decreased by 18.9%, 17.8%, and 25.30% for GC, CC, and PC respectively. Among all the increasing physiological indicators, relative conductivity and MDA showed the greatest increase by 279.32% and 155.56% for PC. A 15-day recovery study was also conducted using MDA and T-AOC as indicators. The results showed that all the tested plants could be tolerant up to the 8 ppm of formaldehyde concentration for 7 days under dynamic fumigation and needed 10–15 days for self-recovery.
Show more [+] Less [-]Short-term effects of ambient air pollution and cardiovascular events in Shiraz, Iran, 2009 to 2015 Full text
2019
Soleimani, Zahra | Darvishi Boloorani, Ali | Khalifeh, Reza | Griffin, Dale W. | Mesdaghinia, Alireza
Air pollution and dust storms are associated with increased cardiovascular hospital admissions. The aim of this study was to investigate the association between short-term exposure to ambient air pollutants and CVD (cardiovascular disease) events in a long-term observational period. The study included the events of cardiovascular diseases (namely coronary artery disease, ischemic heart disease, myocardial infarction, and pneumo thrombo embolism) within the population of Shiraz, from March 21, 2009 to March 20, 2015. Also, each patient’s demographics were recorded. Main meteorological variables and five ambient pollutants (CO, O₃, SO₂, NO₂, and PM₁₀) were recorded. Statistical analysis was performed using linear regression (GLM) and a generalized additive model (GAM) estimating Poisson distribution and adjusted for the main risk factors and ambient meteorological variables. A mild prevalence (51.5%) of coronary artery disease (CAD) was registered in 6425 events. In GLM analysis, we observed an association among the pollutants with the coronary artery disease hospital admissions which was in the order of CO, NO₂, and PM₁₀. The highest association of each pollutant with hospital admission was observed as PM₁₀ at lag 4 (RR = 1.08; 95% CI 1.02, 1.14 and p < 0.05), NO₂ at lag 0 (RR = 1.22; 95% CI 1.00, 1.48), and CO at lag 0 (RR = 1.52 95% CI = (1.16, 1.99)). However, on dusty days, there were significantly higher numbers of referrals of cardiovascular patients (mean = 7.54 ± 4.44 and p = 0.002,) than on non-dusty days. According to these data, dust storms and some types of pollutants in the air are responsible for more admissions to hospitals for cardiovascular problems.
Show more [+] Less [-]Correction to: Temporal trends of contaminants in Arctic human populations Full text
2019
Abass, Khaled | Emelyanova, Anastasia | Rautio, Arja
The article Temporal trends of contaminants in Arctic human populations, written by Khaled Abass, Anastasia Emelyanova and Arja Rautio, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 25 August 2018 without open access.
Show more [+] Less [-]Antioxidant vitamin E protects embryos of Xenopus tropicalis against lambda-cyhalothrin induced embryotoxicity Full text
2019
Jiang, Lin | Chen, Anyu | Niu, Fang | Zhang, Ying
Pesticides are capable of increasing risks to the early development of nontarget organisms through oxidative stress. The supplementation of antioxidants could help to modulate the toxic effects of pesticides, but much remains to be understood in the interactions between pesticides and antioxidants in amphibians. In the present study, the embryotoxicity of a widely used pyrethroid, lambda-cyhalothrin (LCT), and the potential effect of α-tocopherol (TOC) on embryos of Xenopus tropicalis were evaluated. Exposure to LCT did not affect the hatch rate, survival, or body length of the embryos. However, environmentally relevant concentrations of LCT could induce significant malformations on the larvae. Exposure to LCT led to a concentration-dependent induction of oxidative stress and cytotoxicity that subsequently resulted in embryotoxicity. During the early developmental stages, vitamin E could work as a powerful protective antioxidant. The LCT-induced overproduction of reactive oxygen species and increased enzymatic activities were fully inhibited by treatment with 1 μg/L TOC. However, only supplementation with 100 μg/L TOC provided partial protection against the morphological changes caused by LCT. The results from the present study suggest that antioxidant vitamin E possesses protective potential against pyrethroid-induced embryotoxicity in amphibian embryos through the prevention of oxidative stress.
Show more [+] Less [-]Comparing energy state and environmental impacts in ostrich and chicken production systems Full text
2019
Ramedani, Zeynab | Alimohammadian, Loghman | Kheialipour, Kamran | Delpisheh, Parya | Abbasi, Zahra
Energy state and environmental impacts of production systems are of main criteria to reach sustainability. In the present research, ostrich was compared with a broiler production system based on the criteria. The required data was gathered in Boukan Township, West Azerbaijan, Iran, by a questioner method. The total input energy in ostrich and broiler systems was calculated as 150,419.81 MJ (1 ton of bird year)⁻¹ and 344,579.58 MJ (1 ton of bird year)⁻¹, respectively. Diesel fuel and feed (41.39% and 36.95%, respectively) in broiler and electricity (45.87%) in the ostrich production system had the highest energy shares. Eleven impact categories were estimated by SimaPro software in the studied systems. Except for human toxicity, fresh water aquatic ecotoxicity, and terrestrial ecotoxicity, the amounts of other environmental impacts in the ostrich production system were lower than those of the poultry production system. The amount of global warming indicator for the production of 1 ton of broiler chicken was 17,400 kg CO₂ eq year⁻¹ that was equal to 4350 kg CO₂ eq period⁻¹. This value was obtained as 1.68 × 10⁴ kg CO₂ eq year⁻¹ for the production of ostrich meat. In both production systems, feed was the main factor responsible for almost all studied environmental impacts.
Show more [+] Less [-]Phycoremediation of lithium ions from aqueous solutions using free and immobilized freshwater green alga Oocystis solitaria: mathematical modeling for bioprocess optimization Full text
2019
El-Naggar, Noura El-Ahmady | Hamouda, Ragaa A. | Rabei, Nashwa H. | Mousa, Ibrahim E. | Abdel-Hamid, Marwa Salah
Lithium is registered as a serious pollutant that causes environmental damage to an irrigation water supply. Freshwater green alga (Oocystis solitaria) was studied for its potential to remove lithium ions from aqueous solutions. The Plackett–Burman design was applied for initial screening of six factors for their significances for the removal of lithium from aqueous solutions using Oocystis solitaria cells. Among the variables screened, pH, lithium concentration, and temperature were the most significant factors affecting lithium removal. Hence, the levels of these significant variables were further investigated for their interaction effects on lithium removal using the Box–Behnken statistical design. The optimum conditions for maximum lithium removal from aqueous solutions by Oocystis solitaria were the initial lithium concentration of 200 mg/L, contact time of 60 min, temperature of 30 °C, pH 5, and biomass of Oocystis solitaria cells of 1 g/L with agitation condition. Under the optimized conditions, the percentage of maximum lithium removal was 99.95% which is larger than the percentage of lithium removal recorded before applying the Plackett–Burman design (40.07%) by 2.49 times. The different properties of Oocystis solitaria, as an adsorbent, were explored with SEM and via FTIR analysis. The spectrum of FTIR analysis for samples of Oocystis solitaria cells before lithium biosorption showed different absorption peaks at 3394 cm⁻¹, 2068 cm⁻¹, 1638 cm⁻¹, 1398 cm⁻¹, 1071 cm⁻¹, and 649 cm⁻¹ which has been shifted to 3446 cm⁻¹, 2924 cm⁻¹, 1638 cm⁻¹, 1384 cm⁻¹, 1032 cm⁻¹, and 613 cm⁻¹, respectively, after lithium biosorption by the alga. The treatment of aqueous solution containing lithium with Oocystis solitaria cells immobilized in alginate beads removed 98.71% of lithium at an initial concentration of 200 mg/L after 5 h. Therefore, Oocystis solitaria may be considered as an alternative for sorption and removal of lithium ions from wastewaters.
Show more [+] Less [-]The impact of several hydraulic fracking chemicals on Nile tilapia and evaluation of the protective effects of Spirulina platensis Full text
2019
Mahmoud, Mahmoud A. | Abd El-Rahim, Abeer H. | Mahrous, Karima F. | Abdelsalam, Mohamed | Abu-Aita, Nashwa A. | Afify, Mamdouh
Hydraulic fracturing (fracking) chemicals are used to maximize the extraction of hard-to-reach underground energy resources. Large amounts of fracking fluid could escape to the surrounding environments, including underground and surface water resources, during the chemical mixing stage of the hydraulic fracturing water cycle due to equipment failure or human error. However, the impact of pollution resulting from operational discharges is difficult to assess in aquatic ecosystems. In this study, pathological investigations, chromosomal aberrations, DNA damage, and biochemical and hematological parameters were used to evaluate the effects of such chemicals on Nile tilapia. Chromosomal aberrations are considered very sensitive genetic markers of exposure to genotoxic chemicals and are used as indicators of DNA damage. The appearance of different types of chromosomal aberrations (gaps and breaks) due to chemical exposure was significantly reduced by treatment with spirulina. Various deleterious findings in Nile tilapia, in the current study, could attributed to the presence of fracking chemicals in the aquatic environment. However, the presence of spirulina in the diet reduced the hazards of such chemicals. In addition, cytogenetic studies in the current work revealed the importance of spirulina in ameliorating the genotoxic effects of a mixture of some chemicals used in fracking.
Show more [+] Less [-]Process optimization via response surface methodology in the physico-chemical treatment of vegetable oil refinery wastewater Full text
2019
Louhıchı, Ghofrane | Bousselmı, Latifa | Ghrabı, Ahmed | Khounı, Imen
The present paper investigates the efficiency of coagulation/flocculation process using aluminum sulfate as coagulant and CHT industrial flocculent as coagulant aid/flocculent in the treatment of vegetable oil refinery wastewater (VORW). The process optimization was conducted in two steps, jar test experiments for preliminary evaluation to identify the most influencing factors and response surface methodology using Box–Behnken design to investigate the effects of three major factors and their interactions. The variables involved were the coagulant concentration (X₁), flocculent dosage (X₂), and initial pH (X₃) of water samples, while the responses were COD removal (Y1) and residual turbidity (Y2). The optimal conditions obtained by solving the quadratic regression models, as well as by analyzing the response surface contour plots, were as follows: 2.4 g/L of coagulant (aluminum sulfate), 60.05 mg/L of flocculent, and about 9.23 as initial pH. Under these conditions, the coagulation/flocculation treatment was able to achieve 99% of COD removal with total turbidity elimination (100% removal). Analysis of variance showed high variance coefficient (R²) values of 0.929 and 0.836 for COD and turbidity removals, respectively, thus ensuring a satisfactory adjustment of the second-order regression model with the experimental data. This statistical design methodology was demonstrated as an efficient and feasible approach for the optimization of coagulation/flocculation treatment.
Show more [+] Less [-]Evaluation of engine performance and exhaust emission characteristics in a diesel engine using isobutanol— Calophyllum inophyllum biodiesel—diesel ternary blends Full text
2019
Alwi, Azham | Zulkifli, Nurin Wahidah | Sukiman, Nazatul Liana | Yusoff, Ashraf | Zakaria, Zulfattah | Jamshaid, Muhammad | Hasnul, Muhammad Harith | Amzar, Muhammad Syahir
The availability of natural energy resources and the environmental issues are the most significant issues that are often highlighted by the world communities. With regard to these problems, isobutanol is a higher chain alcohol with four carbons which can be derived from biomass resources and it is potential to become an alternative fuel source besides the biodiesel for a diesel engine. The aim of this study is to evaluate the effect of isobutanol with Calophyllum inophyllum methyl ester and diesel as the ternary blend on physicochemical properties, engine performance, and emission characteristics. Five different fuel blends containing Calophyllum inophyllum biodiesel and isobutanol were tested on a single-cylinder direct injection diesel engine at different engine load of brake mean effective pressure. The physicochemical properties of the fuel blends were measured and then compared with neat diesel. The results indicate that the blend containing isobutanol and CIME gives a slight increase in BSEC and EGT and a minimal drop in BTE as compared to that of neat diesel. Besides that, the tested blends show a reduction of carbon monoxide and unburned hydrocarbon emissions. Meanwhile, all the fuel blends show a minimal increase in carbon dioxide and nitrogen oxides emissions, compared to that of neat diesel. Isobutanol can be proved as a preferred substitute for biodiesel and diesel fuels to achieve desired engine performance and emissions level.
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