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Performance and mechanism for cadmium and lead adsorption from water and soil by corn straw biochar

Tong Chi,Jiane Zuo,Fenglin Liu

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0921-y

摘要: Corn straw biochar prepared under 400 °C was the best Cd and Pb adsorption capacity Maximum adsorption capacity of Cd and Pb were 43.48 and 22.73 mg·g , respectively The dominant mechanism of Cd and Pb adsorption was precipitation Biochar could reduce the bioavailability of heavy metals when mixed with soil Cadmium (Cd) and lead (Pb) in water and soil could be adsorbed by biochar produced from corn straw. Biochar pyrolyzed under 400°C for 2 h could reach the ideal removal efficiencies (99.24% and 98.62% for Cd and Pb, respectively) from water with the biochar dosage of 20 g·L and initial concentration of 20 mg·L . The pH value of 4–7 was the optimal range for adsorption reaction. The adsorption mechanism was discussed on the basis of a range of characterizations, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Raman analysis; it was concluded as surface complexation with active sorption sites (-OH, -COO-), coordination with π electrons (C= C, C= O) and precipitation with inorganic anions (OH , CO , SO ) for both Cd and Pb. The sorption isotherms fit Langmuir model rather than Freundlich model, and the saturated sorption capacities for Cd and Pb were 38.91 mg·g and 28.99 mg·g , respectively. When mixed with soil, biochar could effectively increase alkalinity and reduce bioavailability of heavy metals. Thus, biochar derived from corn straw would be a green material for both removal of heavy metals and amelioration of soil.

关键词: Corn straw     Biochar     Heavy metals     Sorption isotherm     Bioavailability    

Fluoride ions adsorption from water by CaCO enhanced Mn–Fe mixed metal oxides

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 236-248 doi: 10.1007/s11705-022-2193-8

摘要: Novel CaCO3-enhanced Mn–Fe mixed metal oxides (CMFC) were successfully prepared for the first time by a simple-green hydrothermal strategy without any surfactant or template combined with calcination process. These oxides were then employed as an adsorbent for adsorptive removal of excess fluoride ions. The adsorbent was characterized by SEM, XPS, XRD, FTIR, and BET analysis techniques. The adsorption property of CMFC toward fluoride ion was analyzed by batch experiments. In fact, CMFC exhibited adsorption capacity of 227.3 mg∙g‒1 toward fluoride ion. Results showed that ion exchange, electrostatic attraction and chemical adsorption were the main mechanism for the adhesion of large amount of fluoride ion on the CMFC surface, and the high adsorption capacity responded to the low pH of the adsorption system. When the fluoride ion concentration was increased from 20 to 200 mg∙L‒1, Langmuir model was more in line with experimental results. The change of fluoride ion adsorption with respect to time was accurately described by pseudo-second-order kinetics. After five cycles of use, the adsorbent still maintains a performance of 70.6% of efficiency, compared to the fresh adsorbent. Therefore, this material may act as a potential candidate for adsorbent with broad range of application prospects.

关键词: mesoporous materials     metal oxides     fluoride ion     adsorption mechanism    

Dual-functional sites for synergistic adsorption of Cr(VI) and Sb(V) by polyaniline-TiO hydrate: Adsorption

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1526-7

摘要:

• PANI/Ti(OH)n(4n)+ exhibited excellent adsorption capacity and reusability.

关键词: Polyaniline/TiO2     Chromium     Antimony     Adsorption     Desorption     Mechanism    

Mass transfer mechanisms in fixed-bed adsorption of erythromycin

SUN Ying, ZHU Jiawen, CHEN Kui, ZHU Sheng, XU Jie

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 353-360 doi: 10.1007/s11705-008-0076-2

摘要: The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined. The equilibrium data in a batch system was well described by a Langmuir isotherm. The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity, ionic strength and pH. A mathematical model was used to simulate the mass transfer mechanism, taking film mass transfer, pore diffusion and axial dispersion into account. The model predictions were consistent with the experimental data and were consequently used to determine the mass transfer coefficients.

关键词: mathematical     diffusion     separation performance     adsorption superficial     mechanism    

A ternary mechanism for the facilitated transfer of metal ions onto metal–organic frameworks: implications

《化学科学与工程前沿(英文)》   页码 1632-1642 doi: 10.1007/s11705-022-2187-6

摘要: Although metal–organic frameworks offer a new platform for developing versatile sorption materials, yet coordinating the functionality, structure and component of these materials remains a great challenge. It depends on a comprehensive knowledge of a “real sorption mechanism”. Herein, a ternary mechanism for U(VI) uptake in metal–organic frameworks was reported. Analogous MIL-100s (Al, Fe, Cr) were prepared and studied for their ability to sequestrate U(VI) from aqueous solutions. As a result, MIL-100(Al) performed the best among the tested materials, and MIL-100(Cr) performed the worst. The nuclear magnetic resonance technique combined with energy-dispersive X-ray spectroscopy and zeta potential measurement reveal that U(VI) uptake in the three metal–organic frameworks involves different mechanisms. Specifically, hydrated uranyl ions form outer-sphere complexes in the surface of MIL-100s (Al, Fe) by exchanging with hydrogen ions of terminal hydroxyl groups (Al-OH2, Fe-OH2), and/or, hydrated uranyl ions are bound directly to Al(III) center in MIL-100(Al) through a strong inner-sphere coordination. For MIL-100(Cr), however, the U(VI) uptake is attributed to electrostatic attraction. Besides, the sorption mechanism is also pH and ionic strength dependent. The present study suggests that changing metal center of metal–organic frameworks and sorption conditions alters sorption mechanism, which helps to construct effective metal–organic frameworks-based sorbents for water purification.

关键词: U(VI)     metal–organic frameworks     adsorption mechanism     metal node    

Efficient CO

Yanxia Wang, Xiude Hu, Tuo Guo, Jian Hao, Chongdian Si, Qingjie Guo

《化学科学与工程前沿(英文)》 2021年 第15卷 第3期   页码 493-504 doi: 10.1007/s11705-020-1967-0

摘要: In this work, nitrogen-doped porous carbons (NACs) were fabricated as an adsorbent by urea modification and KOH activation. The CO adsorption mechanism for the NACs was then explored. The NACs are found to present a large specific surface area (1920.72–3078.99 m ·g ) and high micropore percentage (61.60%–76.23%). Under a pressure of 1 bar, sample NAC-650-650 shows the highest CO adsorption capacity up to 5.96 and 3.92 mmol·g at 0 and 25 °C, respectively. In addition, the CO /N selectivity of NAC-650-650 is 79.93, much higher than the value of 49.77 obtained for the nonnitrogen-doped carbon AC-650-650. The CO adsorption capacity of the NAC-650-650 sample maintains over 97% after ten cycles. Analysis of the results show that the CO capacity of the NACs has a linear correlation ( = 0.9633) with the cumulative pore volume for a pore size less than 1.02 nm. The presence of nitrogen and oxygen enhances the CO /N selectivity, and pyrrole-N and hydroxy groups contribute more to the CO adsorption. Fourier transform infrared spectra analysis indicates that CO is adsorbed onto the NACs as a gas. Furthermore, the physical adsorption mechanism is confirmed by adsorption kinetic models and the isosteric heat, and it is found to be controlled by CO diffusion. The CO adsorption kinetics for NACs at room temperature and in pure CO is in accordance with the pseudo-first-order model and Avramís fractional-order kinetic model.

关键词: porous carbon     CO2 adsorption     nitrogen-doped     adsorption mechanism     kinetics    

A review on the application of nanofluids in enhanced oil recovery

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1165-1197 doi: 10.1007/s11705-021-2120-4

摘要: Enhanced oil recovery (EOR) has been widely used to recover residual oil after the primary or secondary oil recovery processes. Compared to conventional methods, chemical EOR has demonstrated high oil recovery and low operational costs. Nanofluids have received extensive attention owing to their advantages of low cost, high oil recovery, and wide applicability. In recent years, nanofluids have been widely used in EOR processes. Moreover, several studies have focused on the role of nanofluids in the nanofluid EOR (N-EOR) process. However, the mechanisms related to N-EOR are unclear, and several of the mechanisms established are chaotic and contradictory. This review was conducted by considering heavy oil molecules/particle/surface micromechanics; nanofluid-assisted EOR methods; multiscale, multiphase pore/core displacement experiments; and multiphase flow fluid-solid coupling simulations. Nanofluids can alter the wettability of minerals (particle/surface micromechanics), oil/water interfacial tension (heavy oil molecules/water micromechanics), and structural disjoining pressure (heavy oil molecules/particle/surface micromechanics). They can also cause viscosity reduction (micromechanics of heavy oil molecules). Nanofoam technology, nanoemulsion technology, and injected fluids were used during the EOR process. The mechanism of N-EOR is based on the nanoparticle adsorption effect. Nanoparticles can be adsorbed on mineral surfaces and alter the wettability of minerals from oil-wet to water-wet conditions. Nanoparticles can also be adsorbed on the oil/water surface, which alters the oil/water interfacial tension, resulting in the formation of emulsions. Asphaltenes are also adsorbed on the surface of nanoparticles, which reduces the asphaltene content in heavy oil, resulting in a decrease in the viscosity of oil, which helps in oil recovery. In previous studies, most researchers only focused on the results, and the nanoparticle adsorption properties have been ignored. This review presents the relationship between the adsorption properties of nanoparticles and the N-EOR mechanisms. The nanofluid behaviour during a multiphase core displacement process is also discussed, and the corresponding simulation is analysed. Finally, potential mechanisms and future directions of N-EOR are proposed. The findings of this study can further the understanding of N-EOR mechanisms from the perspective of heavy oil molecules/particle/surface micromechanics, as well as clarify the role of nanofluids in multiphase core displacement experiments and simulations. This review also presents limitations and bottlenecks, guiding researchers to develop methods to synthesise novel nanoparticles and conduct further research.

关键词: nanofluid     EOR mechanism     nanoparticle adsorption     interface property     internal property    

New insights into mercury removal mechanism on CeO

Ling Li, Yu He, Xia Lu

《环境科学与工程前沿(英文)》 2018年 第12卷 第2期 doi: 10.1007/s11783-018-1007-1

摘要: First-principles calculations were performed to investigate the mechanism of Hg adsorption and oxidation on CeO (111). Surface oxygen activated by the reduction of Ce to Ce was vital to Hg adsorption and oxidation processes. Hg was fully oxidized by the surface lattice oxygen on CeO (111), without using any other oxidizing agents. HCl could dissociate and react with the Hg adatom on CeO (111) to form adsorbed Hg–Cl or Cl–Hg–Cl groups, which promoted the desorption of oxidized Hg and prevented CeO catalyst deactivation. In contrast, O–H and H–O–H groups formed during HCl adsorption consumed the active surface oxygen and prohibited Hg oxidation. The consumed surface oxygen was replenished by adding O into the flue gas. We proposed that oxidized Hg desorption and maintenance of sufficient active surface oxygen were the rate-determining steps of Hg removal on CeO -based catalysts. We believe that our thorough understanding and new insights into the mechanism of the Hg removal process will help provide guidelines for developing novel CeO -based catalysts and enhance the Hg removal efficiency.

关键词: Elemental mercury removal     Surface adsorption     Ceria     First-principles calculations    

Integrating of metal-organic framework UiO-66-NH2 and cellulose nanofibers mat for high-performance adsorption

《化学科学与工程前沿(英文)》 2022年 第16卷 第9期   页码 1387-1398 doi: 10.1007/s11705-022-2154-2

摘要: UiO-66-NH2 is an efficient material for removing pollutants from wastewater due to its high specific surface area, high porosity and water stability. However, recycling them from wastewater is difficult. In this study, the cellulose nanofibers mat deacetylated from cellulose acetate nanofibers were used to combine with UiO-66-NH2 by the method of in-situ growth to remove the toxic dye, rose bengal. Compared to previous work, the prepared composite could not only provide ease of separation of UiO-66-NH2 from the water after adsorption but also demonstrate better adsorption capacity (683 mg∙g‒1 (T = 25 °C, pH = 3)) than that of the simple UiO-66-NH2 (309.6 mg∙g‒1 (T = 25 °C, pH = 3)). Through the analysis of adsorption kinetics and isotherms, the adsorption for rose bengal is mainly suitable for the pseudo-second-order kinetic model and Freundlich model. Furthermore, the relevant research revealed that the main adsorption mechanism of the composite was electrostatic interaction, hydrogen bonding and π–π interaction. Overall, the approach depicts an efficient model for integrating metal-organic frameworks on cellulose nanofibers to improve metal-organic framework recovery performance with potentially broad applications.

关键词: UiO-66-NH2     cellulose nanofibers     rose bengal     adsorption     mechanism    

Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance in removal of fluoroquinolone antibiotics from water

《环境科学与工程前沿(英文)》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1568-x

摘要:

● A composite aerogel was simply obtained to remove various fluoroquinolones (FQs).

关键词: Composite aerogel of carboxymethyl cellulose and κ-carrageenan     Fluoroquinolone antibiotics     Adsorption performance     Coexisting substances     Adsorption mechanism     Reusability    

Experimental determination of Cd

Farhah Amalya ISMAIL, Ahmad Zaharin ARIS

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 356-364 doi: 10.1007/s11783-013-0488-1

摘要: Carbonate shells have an astonishing ability in the removal of Cd in a short time period with emphasis on being a low cost adsorbent. In the present study, the sorption capacity of carbonate shells was studied for Cd in batch experiments. The influence of different carbonate shell sizes and physico-chemical factors were evaluated and the results were analyzed for its correlation matrices by using Predictive Analytics Software (PASW). The mineralogy state of aqueous solution regarding the saturation index was simulated using PHREEQC to identify the Cd uptake mechanism. The Cd uptake rates were calculated as well as Ca , concentration, pH, ambient humidity and temperature were measured. Cd removal of 91.52% was achieved after 5 h adsorption. The adsorption efficiencies were significantly influenced by pH as they increased with the increase of pH from acidic solution (5.50±0.02) to slightly alkaline (7.60±0.05). In addition, the mineralogy state of aqueous solution calculated from PHREEQC confirmed that the increment of Ca and concentrations in solution was attributed to the dissolution of carbonate shells. Moreover, the ion exchange adsorption mechanism of Cd toward Ca was identified as the process involved in Cd uptake.

关键词: carbonate shell     cadmium     heavy metal     adsorption mechanism     saturation state    

Beta-cyclodextrin adsorbents to remove water pollutants—a commentary

《化学科学与工程前沿(英文)》 2022年 第16卷 第9期   页码 1407-1423 doi: 10.1007/s11705-022-2146-2

摘要: Beta-cyclodextrin-based adsorbent is a promising adsorbent because it has unique characteristics and able to form host-guest complexes with various organic compounds. Adsorption using beta-cyclodextrin-based adsorbent has continuously improved by various preparation strategies and crosslinking agents. This commentary aims to highlight the preparation strategies, properties, and adsorption mechanisms of beta-cyclodextrin-based adsorbents. The adsorbents can be generally classified according to the preparation methods and display high adsorption capacity especially for dyes. Particularly, composite/nanocomposite beta-cyclodextrin-based adsorbents exhibit outstanding adsorption capacity even though the surface area is lower than that of porous and magnetic beta-cyclodextrin-based adsorbents. The beta-cyclodextrin/chitosan functionalized graphene oxide hydrogel with specific surface of 17.6 m2·g–1 yields an extraordinarily maximum adsorption capacity of 1499 mg·g–1 methylene blue, while beta-cyclodextrin/chitosan modified with iron(II, III) oxide nanoparticles displays a much greater maximum adsorption capacity at 2780 mg·g–1. The hydrophobic interaction, functional groups, hydrogen bonding, and electrostatic interaction govern the adsorption to a greater capacity. Although this commentary is not exhaustive, the preparation strategies and illustrated mechanisms provide useful insights into the adsorbent–adsorbate interactions, cost-effective analysis, challenges, and future directions of beta-cyclodextrin-based adsorbents in wastewater treatment.

关键词: beta-cyclodextrin adsorbent     adsorption     inclusion complex     mechanism     water pollutant     wastewater treatment    

Underlying mechanism of the hydrothermal instability of Cu

Nadeen Al-Janabi,Abdullatif Alfutimie,Flor R. Siperstein,Xiaolei Fan

《化学科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 103-107 doi: 10.1007/s11705-015-1552-0

摘要: Water induced decomposition of Cu (BTC) (BTC= benzene-1,3,5-tricarboxylate) metal-organic framework (MOF) was studied using dynamic water vapour adsorption. Small-angle X-ray scattering, Fourier transform infrared spectroscopy and differential scanning calorimetry analyses revealed that the underlying mechanism of Cu (BTC) MOF decomposition under humid streams is the interpenetration of water molecules into Cu-BTC coordination to displace organic linkers (BTC) from Cu centres.

关键词: hydrothermal stability     metal-organic framework (MOF)     open metal sites (OMSs)     dynamic water vapour adsorption    

Adsorption of fluoride on clay minerals and their mechanisms using X-ray photoelectron spectroscopy

Junyi DU, Daishe WU, Huayun XIAO, Ping LI

《环境科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 212-226 doi: 10.1007/s11783-010-0255-5

摘要: This research investigates the adsorption mechanisms of fluoride (F) on four clay minerals (kaolinite, montmorillonite, chlorite, and illite) under different F concentrations and reaction times by probing their fluoride superficial layer binding energies and element compositions using X-ray photoelectron spectroscopy (XPS). At high F concentrations ( = 5–1000 mg·L ), the amount of F adsorbed ( ), amount of hydroxide released by clay minerals, solution F concentration, and the pH increase with increasing . The increases are remarkable at >50 mg·L . The increases significantly by continuously modifying the pH level. At <5–100 mg·L , clay minerals adsorb H to protonate aluminum-bound surface-active hydroxyl sites in the superficial layers and induce F binding. As the increases, F , along with other cations, is adsorbed to form a quasi-cryolite structure. At >100 mg·L , new minerals precipitate and the product depends on the critical Al concentration. At [Al ]>10 mol·L , cryolite forms, while at [Al ]<10 mol·L , AlF is formed. At low (0.3–1.5 mg·L ), proton transfer occurs, and the F adsorption capabilities of the clay minerals increase with time.

关键词: clay mineral     fluoride (F)     adsorption mechanism     X-ray photoelectron spectroscopy (XPS)    

Removal of clofibric acid from aqueous solution by polyethylenimine-modified chitosan beads

Yao NIE,Shubo DENG,Bin WANG,Jun HUANG,Gang YU

《环境科学与工程前沿(英文)》 2014年 第8卷 第5期   页码 675-682 doi: 10.1007/s11783-013-0622-0

摘要: Polyethylenimine (PEI)-modified chitosan was prepared and used to remove clofibric acid (CA) from aqueous solution. PEI was chemically grafted on the porous chitosan through a crosslinking reaction, and the effects of PEI concentration and reaction time in the preparation on the adsorption of clofibric acid were optimized. Scanning electron microscopy (SEM) showed that PEI macromolecules were uniformly grafted on the porous chitosan, and the analysis of pore size distribution indicated that more mesopores were formed due to the crosslinking of PEI molecules in the macropores of chitosan. The PEI-modified chitosan had fast adsorption for CA within the initial 5 h, while this adsorbent exhibited an adsorption capacity of 349 mg·g for CA at pH 5.0 according to the Langmuir fitting, higher than 213 mg·g on the porous chitosan. The CA adsorption on the PEI-modified chitosan was pH-dependent, and the maximum adsorption was achieved at pH 4.0. Based on the surface charge analysis and comparison of different pharmaceuticals adsorption, electrostatic interaction dominated the sorption of CA on the PEI-modified chitosan. The PEI-modified chitosan has a potential application for the removal of some anionic micropollutants from water or wastewater.

关键词: clofibric acid     PEI-modified chitosan     adsorption capacity     adsorption mechanism     electrostatic interaction    

标题 作者 时间 类型 操作

Performance and mechanism for cadmium and lead adsorption from water and soil by corn straw biochar

Tong Chi,Jiane Zuo,Fenglin Liu

期刊论文

Fluoride ions adsorption from water by CaCO enhanced Mn–Fe mixed metal oxides

期刊论文

Dual-functional sites for synergistic adsorption of Cr(VI) and Sb(V) by polyaniline-TiO hydrate: Adsorption

期刊论文

Mass transfer mechanisms in fixed-bed adsorption of erythromycin

SUN Ying, ZHU Jiawen, CHEN Kui, ZHU Sheng, XU Jie

期刊论文

A ternary mechanism for the facilitated transfer of metal ions onto metal–organic frameworks: implications

期刊论文

Efficient CO

Yanxia Wang, Xiude Hu, Tuo Guo, Jian Hao, Chongdian Si, Qingjie Guo

期刊论文

A review on the application of nanofluids in enhanced oil recovery

期刊论文

New insights into mercury removal mechanism on CeO

Ling Li, Yu He, Xia Lu

期刊论文

Integrating of metal-organic framework UiO-66-NH2 and cellulose nanofibers mat for high-performance adsorption

期刊论文

Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance in removal of fluoroquinolone antibiotics from water

期刊论文

Experimental determination of Cd

Farhah Amalya ISMAIL, Ahmad Zaharin ARIS

期刊论文

Beta-cyclodextrin adsorbents to remove water pollutants—a commentary

期刊论文

Underlying mechanism of the hydrothermal instability of Cu

Nadeen Al-Janabi,Abdullatif Alfutimie,Flor R. Siperstein,Xiaolei Fan

期刊论文

Adsorption of fluoride on clay minerals and their mechanisms using X-ray photoelectron spectroscopy

Junyi DU, Daishe WU, Huayun XIAO, Ping LI

期刊论文

Removal of clofibric acid from aqueous solution by polyethylenimine-modified chitosan beads

Yao NIE,Shubo DENG,Bin WANG,Jun HUANG,Gang YU

期刊论文