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Optimization of p-Nitrophenol Degradation and Mineralization Using a Photochemical Reactor 全文
2022
Santolin, Vanessa | Tochetto, Gabriel André | Dervanoski, Adriana | Pasquali, Gean Delise Leal
Advanced oxidative processes are widely used in the degradation of organic compounds. The degradation and mineralization of the PNF was evaluated using an experimental factorial design, using photolysis (UV) and photo-peroxidation (UV/H₂O₂). With the results optimized, degradation kinetics was performed and the experimental data adjusted to mathematical models. In the UV system, it was possible to degrade just over 65% and mineralize 15% over 7 h of reaction; however, with the addition of the oxidizing agent H₂O₂, it was possible to obtain 100% removal of the contaminant, suggesting that there was no formation of intermediate compounds. Kinetics results fitting the first-order model and the velocity constants revealed that degradation is extremely faster in the UV/H₂O₂ system (k₁,UV/H₂O₂ = 0.0580 min⁻¹ > k₁,UV = 0.0018 min⁻¹).
显示更多 [+] 显示较少 [-]Perfluoroalkyl substances (PFAS) in freshwater fish from urban lakes in Hanoi, Vietnam: concentrations, tissue distribution, and implication for risk assessment 全文
2022
Hoa, Nguyen Thi Quynh | Lieu, Tran Thi | Anh, Hoang Quoc | Huong, Nguyen Thi Anh | Nghia, Nguyen Trong | Chuc, Nguyen Thi | Quang, Phan Dinh | Vi, Phung Thi | Tuyen, Le Huu
Concentrations and profiles of 17 perfluoroalkyl substances (PFAS) including 13 perfluorocarboxylic acids (PFA) and 4 perfluoroalkyl sulfonates (PFS) were determined in whole blood, muscle, and liver samples of four freshwater fish species in West Lake and Yen So Lake (Hanoi, Vietnam). Concentrations of total 17 PFAS in fish blood samples ranged from 5.2 to 29 (median 16) ng/mL. Total 17 PFAS levels in liver samples (4.5; 2.7–6.6 ng/g wet weight) were significantly higher than in muscle samples (1.0; 0.51–2.6 ng/g wet weight). More than 90% PFAS burdens in our fish samples were attributed to muscle and blood rather than liver, but contributions of individual compounds varied greatly. The most predominant substances were perfluorooctanesulfonate (PFOS) and PFA with chain lengths from C10 to C14 (i.e., PFDA, PFUnDA, PFDoDA, PFTrDA, and PFTeDA). There is no significant difference in PFAS concentrations between the studied species (i.e., bighead carp, common carp, rohu, and tilapia), but common carp showed specific PFAS profiles as compared to other species (e.g., higher proportions of PFOS and long-chain PFA such as PFTrDA, PFTeDA, and PFHxDA). Daily intake doses of PFOS and perfluorooctanoic acid (PFOA) through fish consumption were markedly lower than the US EPA reference dose of 20 ng/kg/day. Weekly intakes of the sum of PFHxS, PFOS, PFOA, and PFNA in our study were still lower than the EFSA tolerable weekly intake of 4.4 ng/kg/week.
显示更多 [+] 显示较少 [-]Energy efficiency of the industrial sectors in Beijing-Tianjin-Hebei urban agglomeration: does technological gap matter? 全文
2022
Ouyang, Xiaoling | Jian, Qiuping | Jiang, Zhujun
As the political and technological innovation center of China, Beijing-Tianjin-Hebei urban agglomeration (BTHUA) is an important engine of national economic development. However, the BTHUA is faced with uneven industrial development and environmental pollution problems. Energy efficiency of the industrial sector, critical to energy conservation and environmental protection, is the key to achieving green economic transformation. For this reason, this study adopts the parametric meta-frontier approach to measure the industrial total-factor energy efficiency (TFEE) of the BTHUA, centering on the evaluation of regional technology gap ratio (TGR). Empirical results indicate that there are significant regional disparities of industrial TFEE in the BTHUA. In particular, industrial TFEE tends to be underestimated without considering technological heterogeneity in production technology. The TGRs of manufacturing cities, tourist cities, and the modernized metropolis (Beijing) are the highest among the region. On this basis, the influencing factors of industrial TFEE of the BTHUA are further accessed based on the fixed effects model and the Tobit model. This article verifies that the evaluation of TFEE in the BTHUA must take regional technological gap into account, and provides additional empirical evidence on how to promote coordinated regional industrial development and energy efficiency improvement.
显示更多 [+] 显示较少 [-]Efficient Cd(II) Removal from Aqueous Solution Using Mechanically Activated CaCO3: Removal Pathway and Mechanism 全文
2022
Wang, Zhenlei | Zhao, Yunliang | Wen, Tong | Zhang, Tingting | Bai, Haoyu | Song, Shaoxian | Zhang, Qiwu
Cd(II) pollution in water will cause serious threats to the environment and human health. The general remediation protocol for Cd(II) pollution by hydroxide (Ca(OH)₂ or NaOH) is still faced with filtering difficulties and high effluent pH. To develop an applicable method for the Cd(II) removal in water, we prepared an activated calcium carbonate (CaCO₃) material by changing the crystallinity, particle size, and surface activity of CaCO₃, and investigated the corresponding Cd(II) removal capacity from aqueous solutions. The results showed that more than 99.9% of Cd(II) was removed within 10 min in an initial concentration of 50 mg L⁻¹. Moreover, the effluent pH is close to neutral after removal of Cd(II), and the sediment is filtered well. Comparative experiments and characterizations have demonstrated that the excellent Cd(II) removal performance of activated CaCO₃ is due to the mechanical activation changes the surface activity of the original stable CaCO₃, promotes the slow-release dissolution equilibrium of the active carbonate groups, and thus the coprecipitation of cadmium hydroxide and cadmium carbonate on CaCO₃ particles. This research demonstrates that mechanical activation of CaCO₃ could be used as a repair material for efficient removal of heavy metal pollution in water, which can solve the problems of filtration and high effluent pH of alkaline precipitation.
显示更多 [+] 显示较少 [-]The spatial variations of water quality and effects of water landscape in Baiyangdian Lake, North China 全文
2022
Li, Liqing | Chen, Xinghong | Zhang, Meiyi | Zhang, Weijun | Wang, Dongsheng | Wang, Hongjie
Baiyangdian Lake (BYD), a large shallow lake in North China, has complex water landscape patterns that are underlies spatial variations in water quality. In this study, we collected 61 water samples from three water landscapes (reed littoral zones, fish ponds, and open water) and analyzed them for water quality parameters, such as dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP). Water landscape distribution (determined using remote sensing imagery) was then used to assess correlations between water quality parameters and water landscape proportion in differently scaled buffer zones. There was substantial variation across all subareas, with TN and TP concentrations ranging from 0.90 to 4.10 mg/L and 0.06 to 0.18 mg/L, respectively, in class IV of water quality as a whole. Spatial variations in water quality were mainly caused by water landscape distribution and external nutrient inputs. There were negative correlations between DOC, TN, and TP concentrations and the area proportion of reed littoral zones in the 300 and 500 m buffers. In contrast, DOC, TN, and TP concentrations were significantly positively correlated with the area proportion of fish ponds in the 100 m buffer. Furthermore, compared with reed littoral zones, a lower ratio of nitrogen to phosphorus and a higher proportion of dissolved organic nitrogen and tyrosine-like proteins were found in fish ponds. These effects were mainly attributed to the development of internal sediment loadings due to nutrient exchange across the sediment–water interface. Therefore, dredging-based sediment removal from fish ponds should be considered to suppress internal phosphorus loading and accelerate recovery of the BYD ecosystem.
显示更多 [+] 显示较少 [-]Optimum techno-eco performance requisites for vacuum annulus tube collector–assisted double-slope solar desaltification unit integrated modified parabolic concentrator 全文
2022
Singh, Ashok Kumar | Gautam, Samsher
This work presents a novel approach for a double-slope solar desaltification system having parallel array of evacuated annular tube collectors with compound parabolic modified concentrators (DS-SDS-EATC-MCPC) that are observed for eco-design requisites for the optimum performance with environ-economic viabilities. The proposed scheme has been configured to obtain the utmost probable basin’s medium hotness as 99.6 °C of having greater depth of water (0.16 m) for the East–West-faced direction of basin peak cover (30°) along with South-oriented evacuated annular tube (30°). The highest circulation pace (thermo syphon) is obtained ~ 55 kg/h. The generalized efficiencies (energy-exergy) of the system are 46.53% and 3.62%, correspondingly. The everyday distillate (16.94 kg) and its production cost (energy $0.007/kWh; exergy $0.013/kWh) at a titular selling cost ($0.07/l) maintains its goodness. The CO₂ mitigates (energy-exergy) and green earned credits are 139.74 and 77.30 tons, and $1396 and $772.24, in that order. The framework outlay of the scheme is quite stumpy at $200.79, and productivity of the model is set up > 100% that shows the scheme as appreciably realistic. The evident distillate at little operating cost, ecological returns, elevated alleviation, and short payoff period makes the arrangement sustainable, viable for reasonable collector areas, and optimum EATC with MCPC as eco-design requisites for the projected scheme.
显示更多 [+] 显示较少 [-]Asymmetric effect of FDI and public expenditure on population health: new evidence from Pakistan based on non-linear ARDL 全文
2022
Rahman, Saif ur | Chaudhry, Imran Sharif | Meo, Muhammad Saeed | Sheikh, Salman Maqsood | Idrees, Sadia
The core purpose of the study is to examine the asymmetric effect of foreign direct investment (FDI) and population health (measured by life expectancy index). The study takes time series data for 1980–2020. The non-linear autoregressive distributed lag (NARDL) bound testing to cointegration approach is applied to scrutinize an asymmetric association among foreign direct investment, government expenditures, trade openness, public debt, and population health. The study also used an asymmetric causality test to investigate the causal association between the measured variables. The findings affirm that cointegration exists between the variables in the occurrence of asymmetries. The asymmetric causality outcomes confirm that only positive changes in FDI have bidirectional causality to life expectancy while negative shocks have unidirectional that runs from FDI to life expectancy. The government expenditure and foreign direct investment also provided evidence of social sector health welfare in Pakistan. The output shows that increasing government expenditure can cause an increase in life expectancy while decreasing government expenditure can cause a decrease in life expectancy. The study found that investment in health care medical services is paramount to better results as far as government assistance (welfare) gains. The outcomes of the study have given numerous policy suggestions to boost life expectancy in the general public of Pakistan.
显示更多 [+] 显示较少 [-]Environmental-friendly extraction of Peepal (Ficus Religiosa) bark-based reddish brown tannin natural dye for silk coloration 全文
2022
Habib, Noman | Akram, Waseem | Adeel, Shahid | Amin, Nimra | Hosseinnezhad, Mozhgan | Ehsan-ul-Haq,
The present study aims to extract a natural reddish brown colorant from Peepal (Ficus religiosa) for silk dyeing using the microwave radiation process (MW). The colorant was isolated in aqueous and acidic media, and MW treatment for 1, 2, 3, 4, and 5 min has been given to both fabric and extract to observe changes in color intensity. The dye variables have been optimized, and for sustainable shade making process with good fastness, 1.0–5.0 g/100 mL of sustainable chemical and bio-mordants has been employed. It has been found that after microwave treatment for 3 min, under selected conditions, the irradiated aqueous extract has given high color intensity onto silk fabric. The utilization of 3% of Al, 4% of Fe, and 2% of tannic acid (T.A.) as pre chemical mordant whereas 4% of Al, 4% of Fe, and 3% of tannic acid as post chemical mordant have given good color characteristics. In comparison, 4% of acacia and 3% of turmeric and pomegranate while 3% of acacia and turmeric and 4% of pomegranate extracts as post-bio-mordant have given excellent color characteristics. It is concluded that MW treatment has an excellent sustainable efficacy to isolate colorant from Peepal bark for silk dyeing, whereas the inclusion of bio-mordants has not only made the process more sustainable and environmental friendly but also best K/S, and L*a*b* values have been acquired.
显示更多 [+] 显示较少 [-]Domestic wastewater in Indonesia: generation, characteristics and treatment 全文
2022
Widyarani, | Wulan, Diana Rahayuning | Hamidah, Umi | Komarulzaman, Ahmad | Rosmalina, Raden Tina | Sintawardani, Neni
With a 270 million Indonesian population, domestic wastewater is one of the major contributors to wastewater generated from human activities. This review aimed to give an overview of the current state of domestic wastewater generation, characteristics and treatment systems in Indonesia. Overall, grey water quantity in Indonesia was 1 to 4 times higher than black water quantity, while the quantity of untreated grey water was 3 to 6 times higher than untreated black water. Parameters of concern include suspended solids, biochemical oxygen demand, chemical oxygen demand, oil and grease, nitrogen and coliforms. Our analysis shows that grey water can be a significant source of water pollution due to the large quantity and lack of treatment. In addition, black water treatment that relies mainly on on-site treatment is often inadequate due to the lack of quality control for the infrastructure, operation and maintenance. An incentive or penalty scheme to build and ensure the quality of domestic wastewater treatment is required and can be applied at the household, community or central (city) level.
显示更多 [+] 显示较少 [-]Inhibition performances of graphene oxide/silver nanostructure for the microbial corrosion: molecular dynamic simulation study 全文
2022
Kalajahi, Sara Taghavi | Mofradnia, Soheil Rezazadeh | Yazdian, Fatemeh | Rasekh, Behnam | Neshati, Jaber | Taghavi, Lobat | Pourmadadi, Mehrab | Haghirosadat, Bibi Fatemeh
Steel is one of the mainly used materials in the oil and gas industry. However, it is susceptible to the marine corrosion, which 20% of the total marine corrosion is caused by microbiologically influenced corrosion (MIC). The economic and environmental impacts of corrosion are significant, and it is crucial to fight against corrosion in a proper sustainability context and environmental-friendly methods. In this study, the graphene oxide/silver nanostructure (GO-Ag) inhibitory effect on the corrosion of steel in the presence of sulfate reducing bacteria (SRB) was investigated, via weight loss (WL) and Tafel polarization measurements. Moreover, molecular dynamic (MD) simulations were performed to obtain a deep understanding of the corrosion inhibition effect of GO-Ag. GO-Ag showed a significant antibacterial effect at 80 ppm. Moreover, WL and Tafel polarization measurements illustrated a great inhibition efficiency, which reached up to 84% reduction of WL and 98% reduction of corrosion current density (Icₒᵣᵣ) after 7 days of incubation with GO-Ag. Based on MD simulations, bonding energy reached to the larger value in the presence of GO-Ag, which indicated the ability of graphene oxide nanosheets to be adsorbed on the steel surface and prevent the access of corrosive agents to the steel surface. The radial distribution function (RDF) results implied distance between corrosive agent (water and SRB) and steel surface (Fe atoms), which indicated protection of the steel surface due to the effective adsorption of GO nanosheets through the active sites of the steel surface. The mean square displacement (MSD) result showed smaller displacement of the corrosive particles on the surface of steel, resulting that the GO-Ag molecules bonded with Fe molecules on the surface of steel.
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