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Preparation of montmorillonite grafted polyacrylic acid composite and study on its adsorption properties of lanthanum ions from aqueous solution Full text
2019
Zhou, Yunfei | Yan, Chunjie | Zhou, Sen | Liang, Tian | Wen, Xue
Montmorillonite grafted polyacrylic acid composite (GNM) was prepared by using ultraviolet radiation grafting method in this work. The synthesized materials were characterized by XRF, SEM, FTIR, XRD, TG, and XPS. The experimental equilibrium data indicates that the adsorbent is suitable for the Langmuir model and belongs to the pseudo-second-order kinetic model. The entire adsorption process is spontaneous, endothermic, and chaotically enhanced by thermodynamic analysis. The maximum adsorption capacity of La(III) by GNM was 280.54 mg/g at 313.15 K. In addition, the regeneration experiment shows that the adsorbent has good reusability and stable desorption efficiency. This study demonstrates that GNM has high adsorption performance and La(III) adsorption and regeneration capabilities to solve the water pollution caused by rare earth ions and regeneration capabilities for La(III).
Show more [+] Less [-]The dynamic nexus of crop production and population growth: housing market sustainability pathway Full text
2019
Alola, Andrew Adewale | Alola, Uju Violet
The urban poor residents in South Africa are over time known for imbalance and inadequate housing amidst recent concern of shock in food production. In studying this peculiar problem, this study investigates the cointegration and long-run equilibrium relationship of population growth, crop production, and the housing price in the country. Empirically, a quarterly data from 1975:Q1 to 2015:Q4 is employed using the conventional Autoregressive Distributed Lag. The investigation shows strong significant evidence of cointegration and a quarterly speed of adjustment of 17.2% to long run in the system. Also, as the population grows, a decline in house price index is experienced in the long run. Although unusual, adequate and sustainable housing plan, demand-supply dynamics, in respect to a country’s population expansion could posit observation. But, in the short run, a strongly significant positive association is observed. It shows further that positively short-run and long-run relationships significantly exist between crop production and house price index. In reality, caution is essential in the introduction of land redistribution policy to avoid hampering the housing policies and 2030 housing target of the government.
Show more [+] Less [-]Factors affecting Germany’s green development over 1990–2015: a comprehensive environmental analysis Full text
2019
Rüstemoğlu, Hasan
This study was aimed at providing a comprehensive environmental analysis of Germany from 1990 to 2015. First, an ecological footprint analysis of the country was conducted using bio-capacity and ecological footprint data. Second, possible decoupling of the country’s economic growth and carbon dioxide (CO₂) emissions was examined using the decoupling factor adopted by the Organization for Economic Co-operation and Development (OECD). Third, the factors affecting aggregated and sector (electricity and heat production) emission changes were identified using the Logarithmic Mean Divisia Index (LMDI) method. The empirical findings revealed that Germany experienced a slowly decreasing ecological deficit over the entire period. The decoupling-factor calculations showed absolute decoupling of the country’s real GDP and CO₂ emissions. Based on the LMDI calculations, per capita income and population had increasing impacts on aggregated emissions, whereas energy intensity and carbon intensity curbed them substantially. For electricity and heat production, economic activity was the only CO₂-accelerating factor observed in the study period. In addition, the fuel structure effect, pollution effect, and electricity intensity considerably reduced the emissions of electricity and heat production. It, therefore, is possible to conclude that Germany is an impressive example of environmental sustainability for other nations.
Show more [+] Less [-]Removal of antibiotics from aqueous solutions by nanoparticles: a systematic review and meta-analysis Full text
2019
Malakootian, Mohammad | Yaseri, Mehdi | Faraji, Maryam
Antibiotics, as one of the emerging pollutants, are non-biodegradable compounds and long-term exposure to them may affect endocrine, hormonal, and genetic systems of human beings, representing a potential risk for both the environment and human health. The presence of antibiotics in surface waters and drinking water causes a global health concern. Many researches have stated that conventional methods used for wastewater treatment cannot fully remove antibiotic residues, and they may be detected in receiving waters. It is reported that nanoparticles could remove these compounds even at low concentration and under varied conditions of pH. The current study aimed to review the most relevant publications reporting the use of different nanoparticles to remove antibiotics from aqueous solutions. Moreover, meta-analysis was conducted on the results of some articles. Results of meta-analysis proved that different nanoparticles could remove antibiotics with an acceptable efficiency of 61%. Finally, this review revealed that nanoparticles are promising and efficient materials for degradation and removal of antibiotics from water and wastewater solutions. Furthermore, future perspectives of the new generation nanostructure adsorbents were discussed in this study.
Show more [+] Less [-]Characterizations and mechanisms for synthesis of chitosan-coated Na–X zeolite from fly ash and As(V) adsorption study Full text
2019
Han, Caiyun | Yang, Ting | Liu, Hang | Yang, Liu | Luo, Yongming
Solid waste fly ash with low aluminum of Yunnan Province in China was used as pristine material to prepared chitosan-coated Na–X zeolite, and the obtained composite material was employed as As(V) adsorbent. Then, the prepared materials were characterized by XRD, FT-IR, and XPS. And the results suggested that the low aluminum fly ash was successfully convert into Na–X zeolite, and the mineralization between Si–OH of the obtained Na–X zeolite and C–OH of chitosan was the dominated mechanism for coated chitosan over the surface of Na–X zeolite. From the batch experiments of As(V) removal, it has been found that the coated chitosan could significantly improve As(V) performance of Na–X zeolite. The optimal working pH for removal As(V) by chitosan-coated Na–X zeolite was attained at pH 2.1 ± 0.1, and the maximum adsorption capacity was 63.23 mg/g. And the adsorption data at different interval time was excellent fitted by pseudo-second-order kinetic model. From the analyze of XPS, the results suggested that As(V) uptake over adsorbent by the bond of As–N and As–O and the surface hydroxyl group of Al–OH and –NH₂ were involved in uptake As(V) from acid wastewater.
Show more [+] Less [-]Efficient removal of dyes from dyeing wastewater by powder activated charcoal/titanate nanotube nanocomposites: adsorption and photoregeneration Full text
2019
Lin, Yingchao | Ma, Jun | Liu, Wen | Li, Zeyu | He, Kai
Effective removal of dyes has been widely investigated by the adsorption of powder activated carbon and photodegradation by titanate nanotubes (TNTs). In this study, a facile one-step alkaline-hydrothermal method was applied to synthesize powder activated charcoal–supported TNTs (TNTs@PAC). Adsorption of three representative dyes, i.e., cationic methylene blue (MB), cationic rhodamine B (RhB), and anionic methyl orange (MO), onto TNTs@PAC was evaluated by the adsorption kinetic experiments and adsorption isotherms. The first 30 min is the main time phase of adsorption, and MB, RhB, and MO obtained the experimental equilibrium uptake of 173.30, 115.06, and 106.85 mg/g, respectively, indicating their final removal efficiencies of 100%, 69.36%, and 64.11%, respectively. The increase of pH value reduced adsorption capacity of MO (from 149.35 mg/g at pH of 2 to 96.99 mg/g at pH of 10), but facilitated MB adsorption, which was attributed to the charge distribution on the surface of TNTs@PAC and the charge of dyes at different pH. Furthermore, good capacity recoveries of MB by TNTs@PAC (> 99%) were observed after UV irradiation treatment, indicating the used TNTs@PAC can be easily recycled for the adsorption of MB by UV irradiation. Overall, TNTs@PAC is an effective process for remediation of dye-contaminated water because of its adsorption performance for all selected dyes and good regeneration capacity for MB.
Show more [+] Less [-]Constructing magnetic Pt-loaded BiFeO3 nanocomposite for boosted visible light photocatalytic and antibacterial activities Full text
2019
Jaffari, Zeeshan Haider | Lam, Sze Mun | Sin, Jin Chung | R̲ahmān, Eṃ. Ē.
Visible light–responsive Pt-loaded coral-like BiFeO₃ (Pt-BFO) nanocomposite at different Pt loadings was synthesized via a two-step hydrothermal synthesis method. The as-synthesized photocatalyst was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and magnetic hysteresis loop (M-H loop) analyses. The FESEM images revealed that Pt nanoparticles were evenly distributed on the coral-like BFO. The UV–vis DRS results indicated that the addition of Pt dopant modified the optical properties of the BFO. The as-synthesized Pt-BFO nanocomposite was effectively applied for the photodegradation of malachite green (MG) dye under visible light irradiation. Specifically, 0.5 wt% Pt-BFO nanocomposite presented boosted photocatalytic performance than those of the pure BFO and commercial TiO₂. Such a remarkably improved photoactivity could be mainly attributed to the formation of good interface between Pt and BFO, which not only boosted the separation efficiency of charge carriers but also possessed great redox ability for significant photocatalytic reaction. Moreover, the strong magnetic property of the Pt-BFO nanocomposite was helpful in the particle separation along with its great recyclability. The radical scavenger test indicated that hole (h⁺), hydroxyl (·OH) radical, and hydrogen peroxide (H₂O₂) were the main oxidative species for the Pt-BFO photodegradation of MG. Finally, the Pt-BFO nanocomposite was revealed high antibacterial activity towards Bacillus cereus (B. cereus) and Escherichia coli (E. coli) microorganisms, highlighting its potential photocatalytic and antibacterial properties at different industrial and biomedical applications.
Show more [+] Less [-]The asymmetric effect of air quality on cross-industries’ stock returns: evidence from China Full text
2019
Su, Chi-Wei | Wang, Kai-Hua | Tao, Ran | Lobonţ, Oana-Ramona
This paper offers a perspective for the link between air quality and stock returns in China through quantile Granger causality test. Compared to previous studies, the study makes the following innovations. Given the Chinese government plays an important role in economic development, its industrial policies are regarded as a new indispensable supplement of analysis framework apart from investor mood. Next, due to different reflections from cross-industries for different AQ levels, the industry heterogeneity is further considered. Also, nine industries are chosen as a sample, including environmental protection, wind power equipment, steel, photovoltaic equipment, thermal power, tourism, coal, medical service, and medical equipment. Besides, the quantile Granger causality test is robust to misspecification errors when detecting the potential dependence structure between the variables of air quality and stock returns. The empirical results show that the causal link exists in all industries, except medical service. Meanwhile, this impact presents asymmetrical features that when air quality is unhealthy, it has an influence on stock returns of the remaining eight industries. It can be explained by increasing cortisol level, more stringent environmental protection, and industrial policies. These conclusions have essential implications for market participants due to the fact that air quality generates various influences on the stock market. That is why a sustainable environmental design, strict regulatory framework, and special monitoring activities should be highly regarded in China.
Show more [+] Less [-]Eichhornia crassipes biodiesel as a renewable green fuel for diesel engine applications: performance, combustion, and emission characteristics Full text
2019
Venu, Harish | Venkataraman, Dhinakaran | Purushothaman, Prince | Vallapudi, Dhana Raju
This work examines the feasibility of fuelling biodiesel derived from Eichhornia crassipes in a compression ignition engine. This work also proposes water hyacinth biodiesel (WHB) as a potential alternative energy source since the above species is available extensively in freshwater, marine, and aquatic ecosystems throughout the world. WHB was blended with petroleum diesel fuel at various volume proportions of 10%, 20%, 30%, 40%, and 100% and their properties were analyzed as per ASTM standards for its application as biofuel. The prepared test fuels were analyzed experimentally in a single-cylinder diesel engine at constant speed (1500 rev/min) for its performance, combustion, and emission characteristics. Test results projected that the characteristics of 20% WHB + 80% diesel fuel blend were in par with neat diesel fuel in terms of thermal efficiency, HC, CO, and smoke emissions. However, WHB blends resulted in slightly higher levels of CO₂ and NOx emissions. At full load, the attained cylinder pressure and heat release rate of WHB were comparatively lower than diesel fuel. Ignition delay is lowest for B100 blend and therefore the diffusion burning phase of biodiesel phase is found to be dominant in comparison with diesel fuel. For biodiesel blends, the combustion starts earlier due to higher cetane number, lessened delay period, and lowered calorific value followed by lowered HRR. Graphical abstract
Show more [+] Less [-]Correction to: Monte Carlo fingerprinting of the terrestrial sources of different particle size fractions of coastal sediment deposits using geochemical tracers: some lessons for the user community Full text
2019
Gholami, Hamid | Jafari Takhti Najad, Ebrahim | Collins, Adrian L. | Fathabadi, Aboalhasan
The original publication of this paper contains a mistake. The correct University name of the 3rd affiliation is shown in this paper.
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