Уточнить поиск
Результаты 3171-3180 из 4,936
Phytoremediation of a petroleum-polluted soil by native plant species in Lorestan Province, Iran Полный текст
2019
Hatami, Ebrahim | Abbaspour, Ali | Dorostkar, Vajiheh
Petroleum hydrocarbons are potentially toxic for organisms due to the inherent properties, such as solubility, volatility, and biodegradability. The petroleum materials released from corroded old pipelines would pollute soils, shallow groundwater and air as a consequence, and threat the health of human and environment. Therefore, the removal of these compounds from environment is vital. The stability of these pollutants at the soil and their gradual accumulation over time would disrupt the normal function of the soil, such as reduced agricultural capability. In this research, the influence of two plant species (Bromus tectorum L. and Festuca arundinacea) with different amendments including arbuscular mycorrhizal fungi, alfalfa residues, and nutrient solution on the degradation rate of petroleum hydrocarbons in soil was studied. The results showed that the most effective treatment for petroleum remediation was related to B. tectorum L. plant when treated with mycorrhizal fungi and nutrient solution. The degradation rate during 40 days was about 83.27% when compared to the control. Arbuscular mycorrhizal associations are important in the restoration of degraded ecosystems because of the benefits to their symbiotic partners. This fungal phytotechnological mechanism is still in its infancy and there has been little research on aged-contaminated soils.
Показать больше [+] Меньше [-]Biosorption technology for removal of toxic metals: a review of commercial biosorbents and patents Полный текст
2019
de Freitas, Geovani Rocha | da Silva, Meuris Gurgel Carlos | Vieira, Melissa Gurgel Adeodato
In last decades, the biosorption process has become one of the main alternative treatment technologies for the removal of pollutants from dilute aqueous solution. Among these pollutants, toxic metals have drawn attention due to their negative effects in human body and food chain. Even though biosorption is considered a cost-effective and eco-friendly technology to remove toxic metals from dilute wastewaters, there are still obstacles that restrain its commercialization. For this reason, various scientific articles and patents have been published each year to make more effective and economical this technology. This review reports an overview of past achievements, current research of biosorption studies, and future trends for the development of the biosorption as sustainable cleaner technology. Mechanisms of metal uptake, recovery and biosorbent regeneration, process design, commercial application of biosorbents, and patents registered are presented. Finally, future aspects in biosorption research and suggestions for its application will be discussed.
Показать больше [+] Меньше [-]Biochar obtained from cinnamon and cannabis as effective adsorbents for removal of lead ions from water Полный текст
2019
Omidi, Amir Hossein | Cheraghi, Mehrdad | Lorestani, Bahareh | Sobhanardakani, Soheil | Jafari, Azadeh
The feedstock from cinnamon (CI) and cannabis (CA) were used for providing biochar at different temperatures using the pyrolysis method (300, 400, and 600 °C) as appropriate adsorbents for removing Pb(II) ions. The properties of materials were examined with varied techniques. The BET surface area of CI600 and CA600 was higher compared with others. The adsorption efficiency of Pb(II) ions relies on initial Pb(II) concentration, pH, adsorbent dose, equilibrium time, and temperature. The adsorption isotherms of Pb(II) ions were assessed via Langmuir adsorption isotherm and the pseudo-second-order model and electrostatic interaction became visible to play the main role in the adsorption process.
Показать больше [+] Меньше [-]Scenario analysis of ETS revenue allocation mechanism of China: based on a dynamic CGE model Полный текст
2019
Li, Hao | Zhao, Yuhuan | Wang, Song | Lin, Jiang | Cao, Ye | Shi, Qiaoling | Liu, Ya | Xiao, Yanli | Li, Junjie
The successful establishment of China’s emission trading scheme (ETS) could lead the next generation of global climate carbon markets in industrializing and developing countries. The allocation of ETS revenue from auctioning carbon emission allowance is important for the achievement of China’s joint targets of economic growth, mitigation, and welfare improvement. This study develops a dynamic CGE model to evaluate the effects of different ETS revenue allocation mechanisms and identifies the proper mechanism for China’s ETS design. Ten scenarios including business as usual (BAU), no ETS revenue allocation incentive (NA) and other eight ETS revenue allocation scenarios are designed. Simulation results indicate that the tradeoff between economic cost and environmental benefit exists under different ETS revenue allocation mechanisms. ETS revenue is suggested to allocate to household sector through reducing indirect tax and, after 2020, a certain proportion of ETS revenue could be allocated to production sector for improving energy-saving technology (i.e., STP mechanism). This study provides references for policymakers in China to design effective and realistic ETS-related policies. A similar study could be conducted to explore the proper ETS and the revenue allocation policies in other countries that have similar national conditions to China, such as other BRICS countries.
Показать больше [+] Меньше [-]The environmental impacts of financial development in OECD countries: a panel GMM approach Полный текст
2019
Ganda, Fortune
Financial development is often expressed as a private sector initiative earmarked towards motivating economic growth and mitigating poverty. Nonetheless, the need for economic development accompanied by high industrialisation and commercialisation strategies has generated natural environmental effects which have raised enormous concern to green interest groups about whether all the seventeen sustainable development goals will be achieved. This paper investigated the environmental effects of financial development in OECD countries from 2001 to 2012 by employing static models and system GMM analysis. The study utilised foreign direct investments, domestic credit to private sector by banks and domestic credit to private sector as the three proxies of financial development. The effects of these measures of financial development were examined on carbon emissions and greenhouse gases (indicators of environmental quality) and environmental sustainability. In this setting, the findings of the research spotlight that domestic credit to private sector by banks shows a negative and significant relationship with carbon emissions, greenhouse gases and sustainability. Conversely, domestic credit to private sector and economic growth indicates a positive and statistically significant relationship with carbon emissions, greenhouse gases and sustainability. Foreign direct investment is positive and significantly connected with carbon emissions and sustainability but only shows a positive and not significant link with greenhouse gases. The evidence suggested by this analysis adds that the financial system should continue to add more initiatives which consider natural environmental perspectives in their current operations. This present study also confirms the existence of the environmental Kuznets curve (EKC) in carbon emissions (turning point, $109,820), total greenhouse gases (turning point, $74,280) and sustainability (turning point, $112,505). The finding that the turning point of carbon emissions is higher than that of total greenhouse gases indicates why introducing initiatives designed to curb growth of carbon emissions in the respective OECD economies is important.
Показать больше [+] Меньше [-]Biomonitorization of metal ions in the serum of Iranian patients treated with fixed orthodontic appliances in comparison with controls in eastern Iran Полный текст
2019
Moghadam, Mahdjoube Goldani | Hoshyar, Reyhane | Mikulewicz, Marcin | Chojnacka, Katarzyna | Bjørklund, Geir | Pen, Joeri J. | Azadi, Nammam Ali | Pirsaheb, Maghdad | Dashtaki, Meysam | Mansouri, Borhan
The present study aimed to assess the level of metal ions [chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn)] in the serum of patients with fixed orthodontic appliances. One hundred samples (32 males, 68 females) were collected from patients undergoing fixed orthodontic treatment for different periods. A reference (control) group (24 males, 16 females) who had no appliances was used to properly evaluate the changes in the level of these elements in orthodontic appliance users. The element concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). Higher concentrations of metal ions (except for Cr) were found in the serum of the orthodontic group. Bivariate scatter plot showed a highly significant (p < 0.001) correlation between Ni and other elements. The duration of orthodontic treatment increased significantly the Ni levels whereas the bracket type was found to have no significant impact on altering the concentration level of metal ions. The results of the SEM-EDS showed a high variation in the level of metal ions in the brackets and wires. In conclusion, fixed orthodontic appliances increased serum levels of Ni, Zn, Mn, Fe, and Cu but did not change Cr levels.
Показать больше [+] Меньше [-]Phosphorous in the environment: characteristics with distribution and effects, removal mechanisms, treatment technologies, and factors affecting recovery as minerals in natural and engineered systems Полный текст
2019
Azam, Hossain M | Alam, Seemi Tasnim | Hasan, Sayed Mahmudul | Yameogo, Djigui David Stéphane | Kannan, Arvind Damodara | Rahman, Arifur | Kwon, Man Jae
Phosphorus (P), an essential element for living cells, is present in different soluble and adsorbed chemical forms found in soil, sediment, and water. Most species are generally immobile and easily adsorbed onto soil particles. However, P is a major concern owing to its serious environmental effects (e.g., eutrophication, scale formation) when found in excess in natural or engineered environments. Commercial chemicals, fertilizers, sewage effluent, animal manure, and agricultural waste are the major sources of P pollution. But there is limited P resources worldwide. Therefore, the fate, effects, and transport of P in association with its removal, treatment, and recycling in natural and engineered systems are important. P removal and recycling technologies utilize different types of physical, biological, and chemical processes. Moreover, P minerals (struvite, vivianite, etc.) can precipitate and form scales in drinking water and wastewater systems. Hence, P minerals (e.g., struvite, vivianite etc.) are problems when left uncontrolled and unmonitored although their recovery is beneficial (e.g., slow release fertilizers, sustainable P sources, soil enhancers). Sources like wastewater, human waste, waste nutrient solution, etc. can be used for P recycling. This review paper extensively summarizes the importance and distribution of P in different environmental compartments, the effects of P in natural and engineered systems, P removal mechanisms through treatment, and recycling technologies specially focusing on various types of phosphate mineral precipitation. In particular, the factors controlling mineral (e.g., struvite and vivianite) precipitation in natural and engineered systems are also discussed.
Показать больше [+] Меньше [-]Roles of surfactants in pressure-driven membrane separation processes: a review Полный текст
2019
Shi, Lixiu | Huang, Jinhui | Zeng, Guangming | Zhu, Lei | Ku, Yenlin | Shi, Yahui | Yi, Kaixin | Li, Xue
Surfactants widely exist in various kinds of wastewaters which could be treated by pressure-driven membrane separation (PDMS) techniques. Due to the special characteristics of surfactants, they may affect the performance of membrane filtration. Over the last two decades, there are a number of studies on treating wastewaters containing surfactants by PDMS. The current paper gives a review of the roles of surfactants in PDMS processes. The effects of surfactants on membrane performance were discussed via two aspects: influence of surfactants on membrane fouling and enhanced removal of pollutants by surfactants. The characteristics of surfactants in solution and at solid–liquid interface were summarized. Surfactants in membrane filtration processes cause membrane fouling mainly through adsorption, concentration polarization, pore blocking, and cake formation, and fouling degree may be influenced by various factors (feed water composition, membrane properties, and operation conditions). Furthermore, surfactants may also have a positive effect on membrane performance. Enhanced removal of various kinds of pollutants by PDMS in the presence of surfactants has been summarized, and the removal mechanism has been revealed. Based on the current reports, further studies on membrane fouling caused by surfactants and enhanced removal of pollutants by surfactant-aided membrane filtration were also proposed.
Показать больше [+] Меньше [-]Interference mechanism of Sophora alopecuroides L. alkaloids extract on host finding and selection of the Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) Полный текст
2019
Rizvi, Syed Arif Hussain | Ling, Siquan | Tian, Fajun | Liu, Jiali | Zeng, Xinnian
Manipulating insect behavior through the deployment of semiochemicals offers a promising opportunity for protecting crops in a sustainable manner. Therefore, there is still a significant opportunity for the development of natural crop protectants as eco-friendly tools in pest management. In this context, the aim of the current investigation is to find a novel prophylactic against the Asian citrus psyllid (ACP) and to gain a better understanding of the host-finding and selection ability of the ACP towards Murraya paniculata seedlings treated with Sophora alopecuroides alkaloids extract (SAAE). Our results indicate that foliar application of SAAE influences the psyllid host-finding and selection process. The behavioral assay with M. paniculata seedlings treated with 15 and 30 mg/mL of SAAE, with masked visual cues, revealed that only 6.6 and 10.4% psyllids were able to locate the host in the vials. The results also indicate that citrus psyllids mainly rely on both visual and olfaction in host-finding and selection. In choice settling experiments, psyllids settled almost completely on control seedlings rather than on seedlings treated with SAAE at a concentration of 30 mg/mL. Chemical analyses of the alkaloids extract revealed the presence of sophocarpine (33.90%), sophoridine (6.23%), anagyrine (2.77%), matrine (2.38%), lupanine (1.68%) aphylline (0.89%), and sophoramine (0.75%). In further behavioral bioassays with the dominant alkaloids sophocarpine and sophoridine, the alkaloids repelled ACP at higher concentrations of 50 and 70 mg/mL as compared to SAAE. Furthermore, the 50 mg/mL (1:1, v/v) combination of sophocarpine and sophoridine displayed a synergistic effect and showed the maximum behavioral effect as compared to the individual alkaloid. Based on our results, SAAE makes M. paniculata seedlings unattractive to the psyllids, and therefore, alkaloids could be used in reducing the colonization of citrus plants, subsequently curtailing HLB infection.
Показать больше [+] Меньше [-]Effect and threshold of PM2.5 on population mortality in a highly polluted area: a study on applicability of standards Полный текст
2019
Ye, Runze | Cui, Liangliang | Peng, Xiumiao | Yu, Kunkun | Cheng, Fang | Zhu, Yakun | Jia, Chongqi
For assessing the effect and threshold of PM₂.₅ on mortality in highly polluted areas and further studying the standard applicability, daily data on meteorological factors, air pollutants, and mortality were obtained in Jinan, China, from 2011 to 2017. A generalized additive model (GAM) and a distributed lag non-linear model (DLNM) were employed to assess the nonlinearity and the hysteresis of associations. We further explored the breakpoints to evaluate the existence of the threshold. The correlation between mortality and PM₂.₅ was nonlinear. The impact of average PM₂.₅ on non-accidental mortality (RR = 1.11; 95% CI = 1.06, 1.16), cardiovascular disease (CVD) mortality (RR = 1.17; 95% CI = 1.10, 1.24), and respiratory disease (RD) mortality (RR = 1.17; 95% CI = 1.10, 1.24) reached the highest in the current day (lag 0). The excess risks of PM₂.₅ at secondary standard level to non-accidental, CVD, and RD mortality are 8.79% (95% CI = 3.84, 13.98), 14.41% (95% CI = 7.79, 21.43), 15.35% (95% CI = 1.76, 30.74), respectively. The saturation points exist in highly polluted areas. Above the saturation points of 247 μg/m³ for non-accidental mortality, 245 μg/m³ for CVD mortality, and 250 μg/m³ for RD mortality, the model of all three relationships presented a harvesting effect. This study underscores the necessity of the ongoing efforts of reducing particulate air pollution and the adjustment of the standards in seriously polluted areas to adapt to regional conditions. At the same time, for highly polluted areas, it is advocated to strengthen personal protection to decrease the saturation point and control the concentration of pollutants as much as possible, which will substantially save more cost that benefits the public.
Показать больше [+] Меньше [-]