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Journal ArticleDOI: 10.1016/J.SCITOTENV.2021.146116

Enhanced adsorption of Cu(II) and Zn(II) from aqueous solution by polyethyleneimine modified straw hydrochar.

02 Mar 2021-Science of The Total Environment (Elsevier)-Vol. 778, pp 146116-146116
Abstract: Heavy metals removal from aqueous phase by adsorption technique has recently attracted a considerable interest. Although various adsorbing materials have been developed, introducing more functional groups is considered as the most efficient way to promote the adsorption capacity of the selected adsorbent. However, this approach is usually limited in costly modification precursor and unguaranteed loading efficacy. In this study, waste corn straw was converted to adsorbent precursor by hydrothermal carbonization. The obtained hydrochar (HC) was chemically activated before being modified by polyethyleneimine (PEI). Multiple analysis methods including Scanning Electron Microscopy, Fourier Transform Infrared analysis, and X-ray Photoelectron Spectroscopy analysis verified the alkali activated hydrochar (alkali-HC) was more efficacy to enhance PEI grafting than acid activation. Based on this, the modified HC materials obtained a better adsorption performance. The sorption process of Cu(II) and Zn(II) on the acid-PEI-HC, alkali-PEI-HC, and pristine HC fitted the pseudo second order kinetic and Freundlich model well, and was dominated by chemisorption. Among these adsorbents, the adsorption capacity of alkali-PEI-HC to metal ions was the maximum, which was 207.6 mg/g to Zn(II) and 56.1 mg/g to Cu(II) at 298 K. Regeneration tests showed a result of no less than 60% of its removal capacity was achieved after five cycles. Therefore, alkali-PEI-HC performed as a promising composite sorbent for metal ions. In addition, the study described here has provided a new basis for the utilization of hydrochar (1.08 kWh kg−1) derived from agricultural resources as a promising adsorbent precursor.

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Open accessJournal ArticleDOI: 10.1007/S11356-021-14499-W
Ching-Chi Hsu1, Ngo Quang-Thanh2, Fengsheng Chien1, Fengsheng Chien3  +3 moreInstitutions (4)
Abstract: This research measures the relationship between green innovation and the performance of financial development by using an econometric estimation during the year of 2000 to 2018 in 28 Chinese provinces. It is intended to explore the relative role of green technological innovation in driving green financial development in the west and central China, as well as how it influences economic growth in these regions. Ordinary least square (OLS) framework was utilized in mainland China to perform empirical studies by using an econometric estimation. This study claims that China has adopted research-based education system, while those for economic growth and expenditure in the regions while the innovation parts results shows that the tertiary education were 12.42% and 13.53% versus the 10.50% and 10.6% in the eastern area. The research-based education increases the patents in green innovation and boosts the environmental policy. The financial development led to green technological development and innovation. Green innovation and financial development decrease the emissions, and it is apparent that as environmental regulations stimulate technical development, the superiority of human resources increases. The findings indicate that green financing reduces short-term lending, thus limiting clean energy overinvestment, while the long-term loans have little impact on renewable energy overinvestment, and the intermediary effect is unmaintainable. Meanwhile, the green financial growth will reduce renewable energy overinvestment and increase renewable energy investment productivity to certain amount.

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Topics: Productivity (50%)

24 Citations


Journal ArticleDOI: 10.1007/S11356-021-14993-1
Abstract: The literature analyzing the ecological impacts of financial development (FD) documents mixed results. In addition, very limited researches consider the role of technological innovation in ecological sustainability even though technological innovation is indispensable to achieve technological advancement, which may help in sustainable development and ecological sustainability. Therefore, this work probes the effects of technological innovation, financial development, and economic growth (GDP) on the ecological footprint (EF) controlling urbanization and employing a STIRPAT framework. The analysis of data from West Asia and Middle East nations from 1990 to 2017 revealed cointegration in the model. The long-run coefficients produced by the continuously updated fully modified technique revealed that a 1% upsurge in technological innovation decreases EF by 0.010%. Interestingly, technological innovation is helpful to decrease EF and enhance economic growth in the West Asia and Middle East (WAME) countries. However, a 1% rise in FD boosts the level of EF by 0.0016% inferring that FD stimulates ecological degradation. Likewise, urbanization in the WAME countries raises EF levels and contributes adversely to ecological quality. In addition to this, the study revealed the environmental Kuznets curve hypothesis in the selected countries accounting for technological innovation, FD, and urbanization in the model. The causal analysis provided evidence of unidirectional causality from FD to EF and bidirectional causality between technological innovation and EF. The study recommends more investment in research and development and strong collaboration between the universities and industries to promote the level of technological innovation for both sustainable development and ecological sustainability. In addition, urban sustainability policies are necessary without decreasing the urbanization level.

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23 Citations


Open accessJournal ArticleDOI: 10.1007/S11356-021-15023-W
Xueying Wu1, Muhammad Sadiq2, Fengsheng Chien3, Quang-Thanh Ngo4  +2 moreInstitutions (4)
Abstract: The study estimates the long-run dynamics of a cleaner environment in promoting the gross domestic product of E7 and G7 countries. The recent study intends to estimate the climate change mitigation factor for a cleaner environment with the GDP of E7 countries and G7 countries from 2010 to 2018. For long-run estimation, second-generation panel data techniques including augmented Dickey-Fuller (ADF), Phillip-Peron technique and fully modified ordinary least square (FMOLS) techniques are applied to draw the long-run inference. The results of the study are robust with VECM technique. The outcomes of the study revealed that climate change mitigation indicators significantly affect the GDP of G7 countries than that of E7 countries. The GDP of both E7 and G7 countries is found depleting due to less clean environment. However, green financing techniques helps to clean the environment and reinforce the confidence of policymakers on the elevation of green economic growth in G7 and E7 countries. Furthermore, study results shown that a 1% rise in green financing index improves the environmental quality by 0.375% in G7 countries, while it purifies 0.3920% environment in E7 countries. There is a need to reduce environmental pollution, shift energy generation sources towards alternative, innovative and green sources.The study also provides different policy implications for the stakeholders guiding to actively promote financial hedging for green financing. So that climate change and envoirnmental pollution reduction could be achieved effectively. The novelty of the study lies in study framework.

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Topics: Environmental pollution (56%), Gross domestic product (55%), Climate change mitigation (53%) ... show more

15 Citations


Journal ArticleDOI: 10.1007/S11356-021-15701-9
Fengsheng Chien1, Fengsheng Chien2, YunQian Zhang1, YunQian Zhang2  +2 moreInstitutions (3)
Abstract: This study measures the energy rebound effects of Chinese energy and coal power use in Chinese energy-intensive industries by using latent class stochastic frontier models like LMDI, and other various econometric estimation approach for coal-supplying regions in China ranging between 1992 and 2018. The findings reveals that China’s coal sector’s average capacity consumption is 0.81%, with a pattern of first increasing and then decreasing, falling to 0.68% in 2016 specifically. The coal capacity operation rate concerning low as well as depleted regions is generally strong, with limited space for expansion. In 2015 and 2016, the utilization rate of coal production potential in moderate-producing areas fell about 42%. Economic development variables affect the capacity utilization levels of moderate, weak, and depleted generating regions. At the same time, the price volatility cannot induce a practical improvement in the ability utilization rate, which means that China’s coal industry is mainly un-marketized. China’s energy efficiency increased about 19.98% among 2000 and 2016, while the rapidest expansion pattern has been noted in the eastern province at 39.86%, next to central (11.71%) and western regions (9.59%). The take back impact via the renewable energy and renewable productivity channels is estimated as 12.34% and 25.40%, respectively. Therefore, the take back impact is of significant importance regarding energy preservation, as China’s cumulative renewable energy use is equal to China’s aggregate energy use. On such findings, recent research also contributed by presenting novel policy implications for key stakeholders.

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Topics: Renewable energy (54%), Utilization rate (53%), Coal (53%) ... show more

5 Citations


Open accessJournal ArticleDOI: 10.3390/EN14123470
11 Jun 2021-Energies
Abstract: In selected South Asian countries, the study intends to investigate the relationship between urban population (UP), carbon dioxide (CO2), trade openness (TO), gross domestic product (GDP), foreign direct investment (FDI), and renewable energy (RE). Fully modified ordinary least square (FMOLS) and dynamic ordinary least square (DOLS) models for estimation were used in the study, which covered yearly data from 1990 to 2019. We used Levin–Lin–Chu, Im–Pesaran–Shin, and Fisher PP tests for the stationarity of the variables. The outcomes of the panel cointegration approach looked at whether there was a long-run equilibrium nexus between selected variables in Pakistan, Bangladesh, India, and Sri Lanka. The FMOLS approach was also used to assess the relationship, and the results suggest that there is a significant and negative nexus between FDI and renewable energy in south Asian nations. The study’s findings reveal a strong and favorable relationship between GDP and renewable energy use. In South Asian nations (Sri Lanka, Pakistan, India, and Bangladesh), the FMOLS and DOLS findings are nearly identical, but the authors used the DOLS model for robustification. According to the findings, policymakers in South Asian economies (Sri Lanka, Pakistan, India, and Bangladesh) should view GDP and FDI as fundamental policy instruments for environmental sustainability. To reduce reliance on hazardous energy sources, the government should also reassure financial sectors to participate in renewable energy.

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Topics: Energy source (55%), Gross domestic product (54%), Population (52%) ... show more

4 Citations


References
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49 results found


Journal ArticleDOI: 10.1016/J.CEJ.2015.08.014
Abstract: With the awareness of the need for optimal and sustainable use of natural resources, hydrothermal treatment of biomass and biomass waste for energy and resource recovery has received increasing attention. In this context, hydrochars produced by hydrothermal treatment of biomass, which have been traditionally employed as catalyst supports or adsorbents, are now of considerable interest as precursors for activated carbons. Activated carbon produced from hydrochars has been widely used in applications such as energy storage, environmental remediation and resource recovery. Apart from savings in energy and resource conservation, hydrochars are of interest in activated carbon production because they possess unique attributes such as high density of oxygenated functional groups (OFGs) and low degree of condensation which can be tailored to produce activated carbons with specific and desired characteristics. This review aims to integrate the current knowledge on hydrothermal carbonization of biomass waste in the context of resource and energy recovery. Specifically, we bring together recent advances made in this area through a systematic and critical review of the production of activated carbon from hydrochars. Mechanisms involved in the production of hydrochars with different surface characteristics in response to variations in the operating parameters are critically reviewed. The current knowledge gaps and challenges involved in the hydrothermal carbonization of biomass waste are critically evaluated with suggestions for further research.

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Topics: Hydrothermal carbonization (58%), Biomass (55%), Resource recovery (51%)

575 Citations


Journal ArticleDOI: 10.1016/J.WATRES.2003.10.040
01 Feb 2004-Water Research
Abstract: In the present work, the usefulness of grape stalks wastes generated in the wine production process has been investigated for the removal of copper and nickel ions from aqueous solutions. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact. The influence of pH, sodium chloride and metal concentration on metal removal has been studied. Uptake showed a pH-dependent profile. Maximum sorption for both metals was found to occur at around pH 5.5-6.0. An increase of sodium chloride concentration caused a decrease in metal removal. Langmuir isotherms, at pH 6.0, for each metal were used to describe sorption equilibrium data. Maximum uptake obtained was 1.59x10(-4) mol of copper and 1.81x10(-4) mol of nickel per gram of dry sorbent. Sorption of copper and nickel on grape stalks released an equivalent amount of alkaline and alkaline earth metals (K+, Mg2+, Ca2+) and protons, indicating that ionic exchange is predominantly responsible for metal ion uptake. Fourier transform infrared (FTIR) spectrometry analysis indicated that lignin C-O bond might be involved in metal uptake. Equilibrium batch sorption studies were also performed using a two metal system containing (Cu(II)+Ni(II)). In the evaluation of the two metal sorption system performance, single isotherm curves had to be replaced by three-dimensional sorption isotherm surface. In order to describe the isotherm surface mathematically, the extended-Langmuir model was used. Nickel was found to be much more sensitive to the presence of copper than copper is to the presence of nickel.

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Topics: Sorption (64%), Nickel (57%), Copper (56%) ... show more

408 Citations


Journal ArticleDOI: 10.1016/J.BIORTECH.2017.08.178
Yaoyu Zhou1, Xiaocheng Liu1, Yujia Xiang1, Pei Wang2  +6 moreInstitutions (2)
Abstract: Highly efficient simultaneous removal of Cu(II) and tetracycline (TET) from aqueous solution was accomplished by iron and zinc doped sawdust biochar (Fe/Zn-biochar). The mutual effects and inner mechanisms of their adsorption onto Fe/Zn-biochar were systematically investigated via sole and binary systems, sorption isotherm and adsorption kinetics models. The liquid-film diffusion step might be the rate-limiting step for tetracycline, the interaction of Cu(II) was more likely controlled by both intra particle diffusion model and liquid film diffusion model. The fitting of experimental data with kinetic models, Temkin model indicates that the adsorption process of tetracycline and Cu(II) involve chemisorption, and physico-chemical adsorption, respectively. There exists site competition and enhancement of Cu(II) and tetracycline on the sorption to Fe/Zn-biochar. The results of this study indicate that modification of biochar derived from sawdust shows great potential for simultaneous removal of Cu(II) and tetracycline from co-contaminated water.

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Topics: Adsorption (56%), Sorption (52%), Biochar (52%) ... show more

307 Citations


Journal ArticleDOI: 10.1016/J.BIOMBIOE.2012.12.004
Abstract: Hydrothermal carbonization (HTC) is a pretreatment process for making a homogenized, carbon rich, and energy-dense solid fuel, called biochar, from lignocellulosic biomass. Corn stover, miscanthus, switch grass, and rice hulls were treated with hot compressed water at 200, 230, and 260 °C for 5 min. Mass yield is as low as 41% of the raw biomass, and decreases with increasing HTC temperature. Higher heating values (HHV) increase up to 55% with HTC pretreatment temperature. Up to 90% of calcium, magnesium, sulfur, phosphorus, and potassium were removed with HTC treatment possibly due to hemicellulose removal. At a HTC temperature of 260 °C, some structural Si was removed. All heavy metals were reduced by HTC treatment. The slagging and fouling indices are reduced with HTC treatment relative to that of untreated biomass. Chlorine content, a concern only for raw and HTC 200 switch grass, was reduced to a low slagging range at 230 °C, and 260 °C. Alkali index was medium for raw biomass but decreased by HTC.

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Topics: Lignocellulosic biomass (55%), Hydrothermal carbonization (55%), Biochar (51%) ... show more

280 Citations


Journal ArticleDOI: 10.1016/J.BIORTECH.2007.01.056
Y. Kim1, Wayne J. Parker1Institutions (1)
Abstract: Pyrolysis to produce bio-oil from sewage sludge is a promising way, to not only improve the economical value, but also to reduce pollutants associated with sludge. The aim of this study was to evaluate the production of oil from primary, waste activated and digested sludges. The pyrolysis was performed in a laboratory-scale horizontal batch reactor. The operating temperature ranged from 250 degrees C to 500 degrees C, while a gas phase residence time of 20 min was maintained with 50 ml/min of nitrogen gas as a purge flow. The maximum oil yield was achieved with primary sludge at 500 degrees C. Temperature and volatile solids were the most important factors affecting the yield of oil and char, however, sludge type also affected both results. Pre-treatment of sludge with either acids, a base or a catalyst (zeolite) did not improve the quantity of oil produced. The economic values of the oil produced from primary, TWAS, and digested sludges were estimated as 9.9, 5.6, and 6.9 cent/kg-ds when the value of oil is 32 cent/kg-oil.

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Topics: Sludge (65%), Activated sludge (61%), Sewage treatment (58%) ... show more

271 Citations