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Fe-Mn-sepiolite as an effective heterogeneous Fenton-like catalyst for the decolorization of reactive

Chengyuan SU,Weiguang LI,Xingzhe LIU,Xiaofei HUANG,Xiaodan YU

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 37-45 doi: 10.1007/s11783-014-0729-y

摘要： A study of the decolorization of reactive brilliant blue in an aqueous solution using Fe-Mn-sepiolite as a heterogeneous Fenton-like catalyst has been performed. The Fourier transform infrared (FTIR) spectra of the catalyst showed bending vibrations of the Fe-O. The X-ray diffraction (XRD) patterns of the catalyst showed characteristic diffraction peaks of α-Fe O , γ-Fe O and MnO. A four factor central composite design (CCD) coupled with response surface methodology (RSM) was applied to evaluate and optimize the important variables (catalyst addition, hydrogen peroxide dosage, initial pH value and initial dye concentration). When the reaction conditions were catalyst dosage= 0.4 g, [H O ]= 0.3 mL, pH= 2.5, [reactive brilliant blue] = 50 mg·L , and volume of solution= 500 mL at room temperature, the decolorization efficiency of reactive brilliant blue was 91.98% within 60 min. Moreover, the Fe-Mn-sepiolite catalyst had good stability for the degradation of reactive brilliant blue even after six cycles. Leaching of iron ions (<0.4 mg·L ) was observed. The decoloring process was reactive brilliant blue specific via a redox reaction. The benzene ring and naphthalene ring were first oxidized to open ring; these were then oxidized to the alcohol and carboxylic acid. The reactive brilliant blue was decomposed mainly by the attack of ·OH radicals including surface-bound ·OH radicals generated on the catalyst surface.

关键词： Fe-Mn-sepiolite catalyst     heterogeneous Fenton-like     reactive brilliant blue     homogeneous precipitation method     hydroxyl radical    

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Removal of decabromodiphenyl ether (BDE-209) by sepiolite-supported nanoscale zerovalent iron

Rongbing FU,Na MU,Xiaopin GUO,Zhen XU,Dongsu BI

《环境科学与工程前沿（英文）》 2015年 第9卷 第5期   页码 867-878 doi: 10.1007/s11783-015-0800-3

摘要： Nanoscale zerovalent iron (nZVI) synthesized using sepiolite as a supporter was used to investigate the removal kinetics and mechanisms of decabromodiphenyl ether (BDE-209). BDE-209 was rapidly removed by the prepared sepiolite-supported nZVI with a reaction rate that was 5 times greater than that of the conventionally prepared nZVI because of its high surface area and reactivity. The degradation of BDE-209 occurred in a stepwise debromination manner, which followed pseudo-first-order kinetics. The removal efficiency of BDE-209 increased with increasing dosage of sepiolite-supported nZVI particles and decreasing pH, and the efficiency decreased with increasing initial BDE-209 concentrations. The presence of tetrahydrofuran (THF) as a cosolvent at certain volume fractions in water influenced the degradation rate of sepiolite-supported nZVI. Debromination pathways of BDE-209 with sepiolite-supported nZVI were proposed based on the identified reaction intermediates, which ranged from nona- to mono-brominated diphenylethers (BDEs) under acidic conditions and nona- to penta-BDEs under alkaline conditions. Adsorption on sepiolite-supported nZVI particles also played a role in the removal of BDE-209. Our findings indicate that the particles have potential applications in removing environmental pollutants, such as halogenated organic contaminants.

关键词： sepiolite-supported nanoscale zerovalent iron     decabromodiphenyl ether     debromination     adsorption     mechanism    

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Excellent performance of Cu-Mn/Ti-sepiolite catalysts for low-temperature CO oxidation

Yong Song,Lisha Liu,Zhidan Fu,Qing Ye,Shuiyuan Cheng,Tianfang Kang,Hongxing Dai

《环境科学与工程前沿（英文）》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0908-8

摘要： Sepiolite is clay mineral with a 2:1 layered structure. Ti-pillars have an impact on physicochemical property of the sample. 30Mn5Cu/Ti-Sep shows excellent catalytic activity for the oxidation of CO. The interaction, reducibility, and oxygen mobility govern the activity. The Ti-modified sepiolite (Ti-Sep)-supported Mn-Cu mixed oxide ( Mn5Cu/Ti-Sep) catalysts were synthesized using the co-precipitation method. The materials were characterized by the X-ray diffraction scanning electron microscope, N adsorption-desorption, H -TPR, O -TPD, and XPS techniques, and their catalytic activities for CO oxidation were evaluated. It was found that the catalytic activities of Mn5Cu/Ti-Sep were higher than those of 5Cu/Ti-Sep and 30Mn/Ti-Sep, and the Mn/Cu molar ratio had a distinct influence on catalytic activity of the sample. Among the Mn5Cu/Ti-Sep samples, the 30Mn5Cu/Ti-Sep catalyst showed the best activity (which also outperformed the 30Mn5Cu/Sep catalyst), giving the highest reaction rate of 0.875 × 10 mmol·g ·s and the lowest and of 56°C and 86°C, respectively. Moreover, the 30Mn5Cu/Ti-Sep possessed the best low-temperature reducibility, the lowest O desorption temperature, and the highest surface Mn /Mn atomic ratio. It is concluded that factors, such as the strong interaction between the copper or manganese oxides and the Ti-Sep support, good low-temperature reducibility, and good mobility of chemisorbed oxygen species, were responsible for the excellent catalytic activity of 30Mn5Cu/Ti-Sep.

关键词： Ti-modified sepiolite     Supported Mn-Cu mixed oxide     Low-temperature reducibility     Strong metal-support interaction     CO oxidation    

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Effects of sepiolite on stabilization remediation of heavy metal-contaminated soil and its ecological

Yuebing SUN,Dan ZHAO,Yingming XU,Lin WANG,Xuefeng LIANG,Yue SHEN

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 85-92 doi: 10.1007/s11783-014-0689-2

摘要： Stabilization in the remediation of heavy metal contaminated soils has been gaining prominence because of its cost-effectiveness and rapid implementation. In this study, microbial properties such as microbial community and enzyme activities, chemical properties such as soil pH and metal fraction, and heavy metal accumulation in spinach ( ) were considered in assessing stabilization remediation effectiveness using sepiolite. Results showed that soil pH values increased with rising sepiolite concentration. Sequential extraction results indicated that the addition of sepiolite converted significant amounts of exchangeable fraction of Cd and Pb into residual form. Treatments of sepiolite were observed to reduce Cd and Pb translocation from the soil to the roots and shoots of spinach. Concentrations of Cd and Pb exhibited 12.6%–51.0% and 11.5%–46.0% reduction for the roots, respectively, and 0.9%–46.2% and 43.0%–65.8% reduction for the shoots, respectively, compared with the control group. Increase in fungi and actinomycete counts, as well as in catalase activities, indicated that soil metabolic recovery occurred after sepiolite treatments.

关键词： stabilization remediation     heavy metals     sepiolite     soil quality     spinach (Spinacia oleracea)    

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Modeling of bentonite/sepiolite plastic concrete compressive strength using artificial neural network

Ali Reza GHANIZADEH, Hakime ABBASLOU, Amir Tavana AMLASHI, Pourya ALIDOUST

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 215-239 doi: 10.1007/s11709-018-0489-z

摘要： Plastic concrete is an engineering material, which is commonly used for construction of cut-off walls to prevent water seepage under the dam. This paper aims to explore two machine learning algorithms including artificial neural network (ANN) and support vector machine (SVM) to predict the compressive strength of bentonite/sepiolite plastic concretes. For this purpose, two unique sets of 72 data for compressive strength of bentonite and sepiolite plastic concrete samples (totally 144 data) were prepared by conducting an experimental study. The results confirm the ability of ANN and SVM models in prediction processes. Also, Sensitivity analysis of the best obtained model indicated that cement and silty clay have the maximum and minimum influences on the compressive strength, respectively. In addition, investigation of the effect of measurement error of input variables showed that change in the sand content (amount) and curing time will have the maximum and minimum effects on the output mean absolute percent error (MAPE) of model, respectively. Finally, the influence of different variables on the plastic concrete compressive strength values was evaluated by conducting parametric studies.

关键词： bentonite/sepiolite plastic concrete     compressive strength     artificial neural network     support vector machine     parametric analysis    

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Adsorption property of direct fast black onto acid-thermal modified sepiolite and optimization of adsorption

Chengyuan SU, Weiguang LI, Yong WANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 503-511 doi: 10.1007/s11783-012-0477-9

摘要： The adsorption of direct fast black onto acid-thermal modified sepiolite was investigated. Batch adsorption experiments were performed to evaluate the influences of experimental parameters such as initial dye concentration, initial solution pH and adsorbent dosage on the adsorption process. The three-factor and three-level Box-Behnken response surface methodology (RSM) was utilized for modeling and optimization of the adsorption conditions for direct fast black onto the acid-thermal modified sepiolite. The raw sepiolite was converted to acid-thermal modified sepiolite, and changes in the fourier transform infrared spectrum (FTIR) adsorption bands of the sample were noted at 3435 cm and 1427 cm . The zeolitic water disappeared and the purity of sepiolite was improved by acid-thermal modification. The decolorization rate of direct fast black adsorbed increased from 68.2% to 98.9% on acid-thermal modified sepiolite as the initial solution pH decreased from 10 to 2. When the adsorbent dosage reached to 2.5 g·L , 2.0 g·L , 1.5 g·L and 1.0 g·L , the decolorization rate was 90.3%, 86.7%, 61.0% and 29.8%, respectively. When initial dye concentration increased from 25 to 200 mg·L , the decolorization rate decreased from 91.9% to 60.0%. The RSM results showed that the interaction between adsorbent dosage and pH to be a significant factor. The optimum conditions were as follows: the adsorbent dosage 1.99 g·L , pH 4.22, and reaction time 5.2 h. Under these conditions, the decolorization rate was 95.1%. The three dimensional fluorescence spectra of direct fast black before and after treatment showed that the direct fast black was almost all adsorbed by the acid-thermal modified sepiolite.

关键词： direct fast black     acid-thermal modified sepiolite     adsorption     response surface methodology    

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标题 作者 时间 类型 操作

Fe-Mn-sepiolite as an effective heterogeneous Fenton-like catalyst for the decolorization of reactive

Chengyuan SU,Weiguang LI,Xingzhe LIU,Xiaofei HUANG,Xiaodan YU

期刊论文

Removal of decabromodiphenyl ether (BDE-209) by sepiolite-supported nanoscale zerovalent iron

Rongbing FU,Na MU,Xiaopin GUO,Zhen XU,Dongsu BI

期刊论文

Excellent performance of Cu-Mn/Ti-sepiolite catalysts for low-temperature CO oxidation

Yong Song,Lisha Liu,Zhidan Fu,Qing Ye,Shuiyuan Cheng,Tianfang Kang,Hongxing Dai

期刊论文

Effects of sepiolite on stabilization remediation of heavy metal-contaminated soil and its ecological

Yuebing SUN,Dan ZHAO,Yingming XU,Lin WANG,Xuefeng LIANG,Yue SHEN

期刊论文

Modeling of bentonite/sepiolite plastic concrete compressive strength using artificial neural network

Ali Reza GHANIZADEH, Hakime ABBASLOU, Amir Tavana AMLASHI, Pourya ALIDOUST

期刊论文

Adsorption property of direct fast black onto acid-thermal modified sepiolite and optimization of adsorption

Chengyuan SU, Weiguang LI, Yong WANG

期刊论文