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Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1229-x

摘要： Functional groups of AM and EDTA in composite increased removal of Cr(VI) and CR. Removal process reached equilibrium within 30 min and was minimally affected by pH. Elimination of Cr(VI) was promoted by coexisting CR. Adsorption process of CR was less influenced by the presence of Cr(VI). Mechanisms were electrostatic attraction, surface complexation and anion exchange. We prepared ethylenediaminetetraacetic acid (EDTA)-intercalated MgAl-layered double hydroxide (LDH-EDTA), then grafted acrylamide (AM) to the LDH-EDTA by a cross-linking method to yield a LDH-EDTA-AM composite; we then evaluated its adsorptive ability for Congo red (CR) and hexavalent chromium (Cr(VI)) in single and binary adsorption systems. The adsorption process on LDH-EDTA-AM for CR and Cr(VI) achieved equilibrium quickly, and the removal efficiencies were minimally affected by initial pH. The maximum uptake quantities of CR and Cr(VI) on LDH-EDTA-AM were 632.9 and 48.47 mg/g, respectively. In mixed systems, chromate removal was stimulated by the presence of CR, while the adsorption efficiency of CR was almost not influenced by coexisting Cr(VI). The mechanisms involved electrostatic attraction, surface complexation, and anion exchange for the adsorption of both hazardous pollutants. In the Cr(VI) adsorption process, reduction also took place. The removal efficiencies in real contaminated water were all higher than those in the laboratory solutions.

关键词： Chromate     Dye adsorption     Simultaneous removal     Cross-linking method     Amino functionalization    

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Removal of nitric oxide from simulated flue gas using aqueous persulfate with activation of ferrous ethylenediaminetetraacetate in the rotating packed bed

《化学科学与工程前沿（英文）》 2023年 第17卷 第4期   页码 460-469 doi: 10.1007/s11705-022-2224-5

摘要： Nitric oxide being a major gas pollutant has attracted much attention and various technologies have been developed to reduce NO emission to preserve the environment. Advanced persulfate oxidation technology is a workable and effective choice for wet flue gas denitrification due to its high efficiency and green advantages. However, NO absorption rate is limited and affected by mass transfer limitation of NO and aqueous persulfate in traditional reactors. In this study, a rotating packed bed (RPB) was employed as a gas–liquid absorption device to elevate the NO removal efficiency (ηNO) by aqueous persulfate ((NH4)2S2O8) activated by ferrous ethylenediaminetetraacetate (Fe2+-EDTA). The experimental results regarding the NO absorption were obtained by investigating the effect of various operating parameters on the removal efficiency of NO in RPB. Increasing the concentration of (NH4)2S2O8 and liquid–gas ratio could promoted the oxidation and absorption of NO while the ηNO decreased with the increase of the gas flow and NO concentration. In addition, improving the high gravity factor increased the ηNO and the total volumetric mass transfer coefficient (KGα) which raise the ηNO up to more than 75% under the investigated system. These observations proved that the RPB can enhance the gas–liquid mass transfer process in NO absorption. The correlation formula between KGα and the influencing factors was determined by regression calculation, which is used to guide the industrial scale-up application of the system in NO removal. The presence of O2 also had a negative effect on the NO removal process and through electron spin resonance spectrometer detection and product analysis, it was revealed that Fe2+-EDTA activated (NH4)2S2O8 to produce •SO4–, •OH and •O2–, played a leading role in the oxidation of NO, to produce NO3– as the final product. The obtained results demonstrated a good applicable potential of RPB/PS/Fe2+-EDTA in the removal of NO from flue gases.

关键词： rotating packed bed     Fe2+-EDTA     sulfate radical     hydroxyl radical     NO removal efficiency    

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Field evidence of decreased extractability of copper and nickel added to soils in 6-year field experiments

Bao Jiang, Dechun Su, Xiaoqing Wang, Jifang Liu, Yibing Ma

《环境科学与工程前沿（英文）》 2018年 第12卷 第2期 doi: 10.1007/s11783-017-0990-y

摘要： The phytotoxicity of added copper (Cu) and nickel (Ni) is influenced by soil properties and field aging. However, the differences in the chemical behavior between Cu and Ni are still unclear. Therefore, this study was conducted to investigate the extractability of added Cu and Ni in 6-year field experiments, as well as the link with their phytotoxicity. The results showed that the extractability of added Cu decreased by 6.63% (5.10%–7.90%), 22.5% (20.6%–23.9%), and 6.87% (0%–17.9%) on average for acidic, neutral, and alkaline soil from 1 to 6 years, although the phytotoxicity of added Cu and Ni did not change significantly from 1 to 6 years in the long term field experiment. Because of dissolution of Cu, when the pH decreased below 7.0, the extractability of Cu in alkaline soil by EDTA at pH 4.0 could not reflect the effects of aging. For Ni, the extractability decreased by 18.1% (10.1%–33.0%), 63.0% (59.2%–68.8%), and 22.0% (12.4%–31.8%) from 1 to 6 years in acidic, neutral, and alkaline soils, respectively, indicating the effects of aging on Ni were greater than on Cu. The sum of ten sequential extractions of Cu and Ni showed that added Cu was more extractable than Ni in neutral and alkaline soil, but similar in acidic soil.

关键词： Copper     Nickel     EDTA     Sequential extraction    

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标题 作者 时间 类型 操作

Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

期刊论文

Removal of nitric oxide from simulated flue gas using aqueous persulfate with activation of ferrous ethylenediaminetetraacetate in the rotating packed bed

期刊论文

Field evidence of decreased extractability of copper and nickel added to soils in 6-year field experiments

Bao Jiang, Dechun Su, Xiaoqing Wang, Jifang Liu, Yibing Ma

期刊论文