Journal Articles - Environment and Environmental Protection - 2021
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PublicationPhotocatalytic degradation of methyl orange dye by Ti3C2–TiO2 heterojunction under solar light( 2021)Photocatalytic activity is a feasible solution to tackle environmental pollution caused by industrial pollutants. In this research, Ti3C2–TiO2 composite with a unique structure was fabricated successfully via a hydrothermal method. Especially, the in-situ transformation of TiO2 from Ti3C2 MXene creates an intimate heterostructure, which leads to prolonging separation and migration of charged carriers. Thus, this Ti3C2–TiO2 composite enhances effectively methyl orange (MO) degradation efficiency (around 99%) after 40 light-exposed minutes. Besides, the optimal concentration of MO solution was estimated at 40 mg/L and Ti3C2–TiO2 photocatalyst also exhibited good stability after five runs. Moreover, the radical trapping test and the MO photodegradation mechanism over Ti3C2–TiO2 system were also demonstrated. This research illustrates the potential of MXenes as effective co-catalysts for photocatalysis and extends the applications of two-dimensional materials.
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PublicationA step toward reducing air pollution in top Asian economies: The role of green energy, eco-innovation, and environmental taxes( 2021)Environmental degradation is significantly studied both in the past and the current literature; however, steps towards reducing the environmental pollution in carbon emission and haze pollution like PM2.5 are not under rational attention. This study tries to cover this gap while considering the carbon emission and PM2.5 through observing the role of renewable energy, non-renewable energy, environmental taxes, and ecological innovation for the top Asian economies from 1990 to 2017. For analysis purposes, this research considers cross-sectional dependence analysis, unit root test with and without structural break (Pesaran, 2007), slope heterogeneity analysis, Westerlund and Edgerton (2008) panel cointegration analysis, Banerjee and Carrion-i-Silvestre (2017) cointegration analysis, long-short run CS-ARDL results, as well as AMG and CCEMG for robustness check. The empirical evidence in both the short- and long-run has confirmed the negative and significant effect of renewable energy sources, ecological innovation, and environmental taxes on carbon emissions and PM2.5. Whereas, non-renewable energy sources are causing environmental degradation in the targeted economies. Finally, various policy implications related to carbon emission and haze pollution like PM2.5 are also provided to control their harmful effect on the natural environment.
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PublicationAgar/maltodextrin/poly(vinyl alcohol) walled montmorillonite composites for removal of methylene blue from aqueous solutions( 2021)Nowadays, the impact of textile pollutants such as methylene blue on aquatic systems is intensively serious over the world. There is a growing interest in the mitigation of these textile compounds using recyclable, high-efficiency, and biodegradable materials. Herein, we report a facile casting method for preparing agar/maltodextrin/poly(vinyl alcohol) walled montmorillonite (AMP–MMT) composites. Specifically, sodium montmorillonite clay was incorporated into hydrogel membranes with the loading rates of 0–30% (w v–1). Composite membranes were physicochemically characterized with physicochemical techniques such as X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and zeta potential measurement. Other measurements of contact angle, moisture, and swelling degree were also conducted. Moreover, the effect of operating parameters such as montmorillonite loading, solution pH, contact time, concentration, and temperature on dye adsorption was explored. Plausible mechanisms of cation exchange, H–bonds, and n–π interactions might shed light on the adsorption of methylene blue on AMP–MMT composite. Nonlinear kinetic and isotherms were used to gain insight into adsorption nature. Composite membrane in our study exhibited high uptake capacity (71.51 mg g–1), good recyclability (at least five cycles), and easy desorption with green eluent of mixed water and ethanol. This work is expected to encourage the use of recyclable, eco-friendly, and biodegradable hydrogel membranes in the water purification.
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PublicationImproving green performance of construction projects through supply chain integration: The role of environmental knowledge( 2021)The implementation of green supply chain integration (GSCI) to achieve green performance (GP) has been confirmed by prior research in many industries, especially manufacturing industries. Despite this fact, very limited research has been performed to investigate the effects of green integration and environmental knowledge (EK) on green performance of construction projects. Therefore, the current study was conducted to fill this gap in the literature. A framework of many hypotheses regarding interactions between green integration (i.e., supplier, internal, and customer integration), environmental knowledge, and green performance was developed and validated by data collected from 19 construction projects in Vietnam, with the support of Structural Equation Modeling. The findings show that environmental knowledge is a significant antecedent to the development of green integration strategies. Moreover, customer integration and supplier integration have direct effects on green performance, whereas internal integration has an indirect effect on green performance through supplier integration. It is surprising to see that internal integration does not have direct effects on both customer integration and green performance. Theoretically, this study is one of the first efforts in construction that develops a framework of green supply chain integration in which the roles of integration and environmental knowledge to achieve green project objectives are highlighted. Practically, our study suggests that construction firms need to accumulate environmental knowledge and develop integration within their firms before implementing green integration strategies at the supply chain level.
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PublicationAssessing the efficiency of constructed wetlands in removing PPCPs from treated wastewater and mitigating the ecotoxicological impacts( 2021)The prevalence of pharmaceuticals and personal care products (PPCPs) in municipal wastewater has led to increased concerns about their impact on both human health and ecosystem. The constructed wetlands have been recognized as one of the cost-effective and green mitigation approaches to remove the PPCPs in the municipal wastewater. In this study, the effectiveness of a full scale constructed wetlands treatment system (CCWTs) in removing the 36 PPCPs was investigated. The load mass of PPCPs discharged by the wastewater treatment plant into the CCWTs was calculated. Removal efficiencies of PPCPs were evaluated based on physicochemical properties such as octanol-water partition coefficient (Log kow), molecular weight (MW, g mol-1) and the acid dissociation constant (pKa).. The CCWTs are especially efficient in removing azithromycin, sertraline, tolfenamic acid, and diphenhydramine with removing efficiency > 88%. However, the removal efficiencies of PPCPs in CCWTs exhibit a large variability, depending on physical and chemical properties of the molecules, with 4.7-96.7% for antibiotics, 5-86% for antidepressant and antiseizure drugs, 3.5-88% for NSAIDs, 29-77% for β- blockers and statins and 5.5-94% for other types of PPCPs. In addition, the environmental risk assessment showed that majority of the PPCPs (excluding sulfamethoxazole) in the effluent yielded low aquatic risk (risk quotient, RQ ≤ 0.1) due to the efficiency of CCWTs. The toxicity index scores were calculated by integration of the predicted and available toxicological hazard data into the prioritization ranking algorithm through Toxicological Prioritization Index (ToxPi).