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Progress in ultrasonic oil-contaminated sand cleaning: a fundamental review Texto completo
2019
Mat-Shayuti, Muhammad Shafiq | Tuan Ya, Tuan Mohammad Yusoff Shah | Abdullah, Mohamad Zaki | Megat Khamaruddin, Putri Nadzrul Faizura | Othman, Nur Hidayati
Steady efforts in using ultrasonic energy to treat oil-contaminated sand started in the early 2000s until today, although pilot studies on the area can be traced to even earlier dates. Owing to the unique characteristics of the acoustic means, the separation of oil from sand has been showing good results in laboratories. This review provides the compilation of researches and insights into the mechanism of separation thus far. Related topics in the areas of oil-contaminated sand characterizations, fundamental ultrasonic cleaning, and cavitation effects are also addressed. Nevertheless, many of the documented works are only at laboratory or pilot-scale level, and the comprehensive interaction between ultrasonic parameters towards cleaning efficiencies may not have been fully unveiled. Gaps and opportunities are also presented at the end of this article.
Mostrar más [+] Menos [-]Effects of residual ozone on the performance of microorganisms treating petrochemical wastewater Texto completo
2019
Fu, Liya | Wu, Changyong | Zhou, Baoying | Zuo, Jiane | Song, Guangqing
This study investigated the effects of residual ozone on the performance of microorganisms treating petrochemical wastewater using batch experiments with low and high ozone dosages (5.0 mg/L and 50.0 mg/L, respectively). The results indicated that the low residual ozone concentration significantly increased COD removal by 24.21% in the biological process compared to control group with no ozone residual, while the high residual ozone concentration showed the opposite effect. In the reactor with low residual ozone concentration (0.45 mg/L), the amount of loosely bound (LB)-extracellular polymeric substances (EPS) in the activated sludge decreased by 23.23%, while the amount of tightly bound (TB)-EPS increased by 129.16% compared to the none-ozone residual reactor. In addition, the low residual ozone was found to improve the bioactivity of activated sludge by 139.73% in the first 30 min of the biological process. In the reactor with high residual ozone concentration (0.91 mg/L), both LB- and TB-EPS of the activated sludge increased, while bioactivity decreased. This implies that low residual ozone in a bio-reactor can enhance microbial activity by increasing contact between the pollutants and cells by removing LB-EPS covering the outer layer of the sludge. The microorganisms in the sludge samples could be classified into three groups representing those that are susceptible to ozone, tolerant to low dose of residual ozone, and resistant to high dose of residual ozone. The resistant bacteria Gemmatimonadaceae uncultured became predominant, with a relative abundance of 11.37%, under low residual ozone conditions, while it decreased at high ozone concentrations. The results showed that a certain amount of residual ozone could stimulate the activity of microorganisms by altering the EPS fraction and structure of the microbial community, and thus it is important for the removal of refractory organics from wastewater in the ozone-biological process.
Mostrar más [+] Menos [-]Consumers’ knowledge, attitude and behavioural patterns towards the liquid wastes (cooking oil) in Istanbul, Turkey Texto completo
2019
Gurbuz, Ismail Bulent | Ozkan, Gulay
This study was carried out to reveal the people’s knowledge level about the harmful effects of waste oils, especially waste cooking oil, on the environment. It also aims to understand the attitude and behavioural patterns related to the safe disposal of them. Istanbul is chosen because it represents the entire country with its diverse socio-demographic and socio-cultural structure. A total of 408 respondents were randomly chosen and interviewed in the designated regions. The research data were obtained by using a structured survey consisting demographic and Likert scale questions. SPSS 23.0 statistical software was used to analyse the survey data. Results suggest that despite the high educational level, participants did not know that household liquid waste has a negative impact on the environment. They disagreed on the statement that liquid waste can damage water resources. Public spots, and formal and informal education were not found effective and failed to make the desired impact. Majority of participants did not know their duties in the disposal of waste. They also did not know where the liquid waste collection units were and what projects were being implemented in their neighbourhood. Fewer participants were concerned at what point and how the hazardous liquid wastes collected by municipalities were disposed of after leaving their habitat and whether these methods were reliable or acceptable. This research concludes that user behaviour was disappointing in cooking oil usage and waste oil disposal. The collection of waste cooking oils remains far below the developed countries.
Mostrar más [+] Menos [-]Characteristic of adsorption cadmium of red soil amended with a ferromanganese oxide-biochar composite Texto completo
2019
Zhou, Qiwen | Liao, Bohan | Lin, Lina | Song, Zhengguo | Khan, Zulqarnain Haider | Lei, Ming
The increasing scarcity of arable land necessitates the development of effective decontamination techniques to re-gain contaminated areas and make them suitable for agricultural and other activities. Herein, we prepare a ferromanganese binary oxide-biochar composite (FMBC) and compare its potential for remediating Cd-contaminated red soil with that of biochar (BC), showing that (i) the obtained adsorption data are well described by the Langmuir model and (ii) Cd adsorption capacity increases with increasing adsorbent dosage. Specifically, the Cd adsorption capacity of FMBC-amended soil (6.72 mg g⁻¹) is demonstrated to significantly exceed that of BC-amended red soil (4.85 mg g⁻¹) and that of the control (2.28 mg g⁻¹) and increases with increasing temperature and pH, while the results of instrumental analyses indicate that Cd sorption on the soil surface occurs via the formation of CdO and Cd(OH)₂. Thus, FMBCs are concluded to play an important role in the adsorption of Cd, having the potential to prevent red soil acidification and improve soil quality, and are found to be promising remediation materials for mitigating the risks posed by Cd-contaminated red soil.
Mostrar más [+] Menos [-]Effect of Activation Time on the Performance and Mechanism of CO2-Activated Wheat Straw Char for the Removal of Cd2+ Texto completo
2019
Li, Mengxue | Shu, Daobing | Liu, Haibo | Chen, Tianhu | Chen, Dong
The removal behavior and characteristic of cadmium (Cd²⁺) on wheat straw char activated by CO₂ were investigated in this study. The equilibrium, kinetics, and removal isotherms were studied. The results of batch experiments revealed that the removal of Cd²⁺ was described well by pseudo-second-order and Langmuir models. The increase in activation time improved the removal of Cd²⁺, especially for the activation time of 84 min. The results suggested that chemisorption of Cd²⁺ on activated carbon was the main reaction mechanism. The maximum removal capacity of Cd²⁺ onto activated WSC-84 was 75.55 mg/g, which was much higher than other three samples activated by CO₂ with other amounts of time. According to the results of SEM, XPS, and FT-IR, complexation with surface oxygen-containing functional groups, ion exchange, and precipitation were the possible mechanisms of the removal process. It is suggested that the experimental results will enhance the comprehensive understanding of the activation of biomass and its utilization in the restoration of Cd-contaminated soil.
Mostrar más [+] Menos [-]Estimating the spatial distribution of environmental suitability for female lung cancer mortality in China based on a novel statistical method Texto completo
2019
Han, Xiao | Guo, Yanlong | Gao, Hong | Ma, Jianmin | Sang, Manjie | Zhou, Sheng | Huang, Tao | Mao, Xiaoxuan
Lung cancer as one of the major causes of cancer mortality has been demonstrated to be closely related to the ambient atmospheric environment, but little has been done in the synthetic evaluation of the linkage between cancer mortality and combined impact of ambient air pollution and meteorological conditions. The present study determined the environmental suitability for female lung cancer mortality associated with air contaminants and meteorological variables. A novel fuzzy matter–element method was applied to identify the spatial distribution and regions for the environmental suitability for the female lung cancer mortality across China in 2013. The membership functions between the cancer mortality and 6 environmental factors, including PM₂.₅, NO₂, SO₂, PM₁₀, the annual mean wind speed, and mean temperature, were generated and the weights of each of the environmental factors were established by the maximum entropy (MaxEnt) model. We categorized the environmental suitability combined with GIS spatial analysis into three zones, including low-suitable, medium-suitable, and high-suitable region where the cancer mortality ranging from low to high rate was identified. These three zones were quantified by the MaxEnt model taking different air pollutants and meteorological variables into consideration. We identified that NO₂ was a most significant factor among the 6 environmental factors with the weight of 24.88%, followed by the annual mean wind speed, SO₂, and PM₂.₅. The high-suitable area, mainly in the North China Plain which is a most heavily contaminated region by air pollution in China, covers 1.6195 million square kilometers, accounting for 17.85% of the total area investigated in this study. Identification of the impact of various environmental factors on cancer mortality in the different suitable area provides a scientific basis for the environmental management, risk assessment, and lung cancer control.
Mostrar más [+] Menos [-]How production-based and consumption-based emissions accounting systems change climate policy analysis: the case of CO2 convergence Texto completo
2019
Karakaya, Etem | Yılmaz, Burcu | Alataş, Sedat
Much of the existing research analyses on emissions and climate policy are dominantly based on emissions data provided by production-based accounting (PBA) system. However, PBA provides an incomplete picture of driving forces behind these emission changes and impact of global trade on emissions, simply by neglecting the environmental impacts of consumption. To remedy this problem, several studies propose to consider national emissions calculated by consumption-based accounting (CBA) systems in greenhouse gas (GHG) assessments for progress and comparisons among the countries. In this article, we question the relevance of PBA’s dominance. To this end, we, firstly, try to assess and compare PBA with CBA adopted in greenhouse gas emissions accounting systems in climate change debates on several issues and to discuss the policy implications of the choice of approach. Secondly, we investigate the convergence patterns in production-based and consumption-based emissions in 35 Annex B countries for the period between 1990 and 2015. This study, for the first time, puts all these arguments together and discusses possible outcomes of convergence analysis by employing both the production- and consumption-based CO₂ per capita emissions data. The empirical results found some important conclusions which challenge most of the existing CO₂ convergence studies.
Mostrar más [+] Menos [-]Correction to: Tracking the Limnoecological History of Lake Hiidenvesi (Southern Finland) Using the Paleolimnological Approach Texto completo
2019
Luoto, Tomi P. | Rantala, Marttiina V. | Tammelin, Mira H.
Erroneous information considering Chironomidae and Chaoboridae accumulation was given in Figure 4 published in Luoto et al. (2017).
Mostrar más [+] Menos [-]Bioaugmentation and Biostimulation of Total Petroleum Hydrocarbon Degradation in a Petroleum-contaminated Soil with Fungi Isolated from Olive Oil Effluent Texto completo
2019
Essabri, Abduelbaset M. A. | Aydinlik, Nur Pasaoglulari | Williams, Ndifreke Etuk
In degradation of total petroleum hydrocarbon, 35 isolates belonging to 11 genera were sanitized and 3 isolates as well as their consortium were initiated to be able to raise in association with petroleum hydrocarbon as sole source of carbon under in vitro circumstances. The isolated strains were grounded on internal transcribed spacer (ITS) rDNA sequence analysis. The fungal strains with the utmost potentiality to reduce petroleum hydrocarbon without emerging antagonistic activities were Aspergillus niger, Penicillium ochrochloron, and Trichodema viride. For fungal growth on petroleum hydrocarbon, P. ochrocholon gained weight of 44%, A. niger 49%, and T. viride 39% within the first 30–40 days. As compared to the controls, these fungi accumulated significantly higher biomass, produced extracellular enzymes, and degraded total petroleum hydrocarbon and A. niger strongly degraded total petroleum hydrocarbon with a degradation of about 71.19%. These observations with GC-MS data confirm that these isolates displayed rapid total petroleum hydrocarbon biodegradation within a period of 60 days and the half-life showed that A. niger was the shortest with t1/2 = 21.280 day⁻¹ corresponding to the highest percent degradation of 71.19% and first-order kinetic fitted into the present study. By multivariate analysis, five main factors were identified by factor analysis (FA). The first factor (F1) of the fungi species accounts for 20.0% which signifies that fungi species controls the degradation of petroleum variability and hierarchical cluster analysis (HCA) as a dendrogram with five observations and three variables shows two predominant clusters order cluster 1 > 2.
Mostrar más [+] Menos [-]Kinetic, equilibrium, and thermodynamic studies on the adsorption of ciprofloxacin by activated carbon produced from Jerivá (Syagrus romanzoffiana) Texto completo
2019
de Oliveira Carvalho, Caroline | Costa Rodrigues, Daniel Lucas | Lima, Éder Cláudio | Santanna Umpierres, Cibele | Caicedo Chaguezac, Diana Fernanda | Machado Machado, Fernando
High specific surface area activated carbon prepared from endocarp of Jerivá (Syagrus romanzoffiana) (ACJ) was used for ciprofloxacin (CIP) antibiotic removal from aqueous effluents. The activated carbon (AC) was characterized via scanning electron microscope, Fourier transform infrared spectroscopy, N₂ adsorption/desorption, and pH value at the zero-charge point. Avrami kinetic model was the one that best fit the experimental results in comparison to the pseudo-first-order and pseudo-second-order kinetic models. The equilibrium data obeyed the Liu isotherm equation, showing a maximum adsorption capacity of 335.8 mg g⁻¹ at 40 °C. The calculated thermodynamic parameters indicate that the adsorption of CIP was spontaneous and endothermic at all studied temperatures. Also, the free enthalpy changes (∆H° = 3.34 kJ mol⁻¹) suggested physical adsorption between CIP and ACJ. Simulated effluents were utilized to check the potential of the ACJ for wastewater purification. The highly efficient features enable the activated carbon prepared from endocarp of Jerivá, an attractive carbon adsorbent, to remove ciprofloxacin from wastewaters.
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