scholarly journals Removal efficiency of hexavalent chromium from wastewater using starch-stabilized nanoscale zero-valent iron

2019 ◽  
Vol 80 (6) ◽  
pp. 1076-1084 ◽  
Author(s):  
Hualin Chen ◽  
Huajun Xie ◽  
Jiangmin Zhou ◽  
Yueliang Tao ◽  
Yongpu Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Reactivity ◽  
Zero Valent Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phase Reduction ◽  
Nanoscale Zero Valent Iron ◽  
Removal Efficiencies ◽  
Ph Range ◽  
Uniform Particle Size

Abstract In this study, starch-stabilized nanoscale zero-valent iron (S-nZVI) was produced using the liquid-phase reduction method. It was used to remove chromium from wastewater, and compared to a commercial nanoscale zero-valent iron (C-nZVI). Both nZVIs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The characterization results showed that S-nZVI had smaller particles and a more uniform particle size distribution than C-nZVI. Both nZVIs showed a core-shell structure with the Fe0 core prominently surrounded by less iron oxides of Fe2+ and Fe3+. The optimal application methods to remove Cr(VI) from wastewater were also explored. The results showed that both the removal efficiencies of total Cr and Cr(VI) increased with increases in the addition of nZVIs, while the removal efficiencies of total Cr and Cr(VI) by S-nZVI were clearly higher than that of C-nZVI, especially in a low pH range (pH = 1.0–6.0). This research indicated that starch-stabilized nanoscale zero-valent iron is a valuable material to remove heavy metals from wastewater due to its stability and high reactivity.

scholarly journals Simultaneous adsorption and reduction of hexavalent chromium on biochar-supported nanoscale zero-valent iron (nZVI) in aqueous solution

2020 ◽  
Vol 82 (7) ◽  
pp. 1339-1349
Author(s):  
Fengfeng Ma ◽  
Bakunzibake Philippe ◽  
Baowei Zhao ◽  
Jingru Diao ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Pseudo Second Order

Abstract Flax straw biochar (FSBC)-supported nanoscale zero-valent iron (nZVI) composite (nZVI-FSBC) combining the advantages of nZVI and biochar was synthesized and tested for Cr(VI) removal efficiency from aqueous solution. Surface morphology and structure of FSBC and nZVI-FSBC were characterized by scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller techniques, which help to clarify the mechanism of Cr(VI) removal from aqueous solution. The adsorption of Cr(VI) onto FSBC and nZVI-FSBC was best described by the pseudo-second-order and the Sips model. Compared with FSBC, nZVI-FSBC remarkably improved the performance in removing Cr(VI) under identical experimental conditions. Due to the collaborative effect of adsorption and reduction of nZVI-FSBC, the adsorption capacity of nZVI-FSBC for Cr(VI) is up to 186.99 mg/g. The results obtained by XPS, XRD, and FTIR confirmed that adsorption and reduction dominated the processes of Cr(VI) removal by nZVI-FSBC. As a supporter, FSBC not only improved the dispersion of nZVI, but also undertook the adsorption task of Cr(VI) removal. The surface oxygen-containing functional groups of nZVI-FSBC mainly participated in the adsorption part, and the nZVI promoted the Cr(VI) removal through the redox reactions. These observations indicated that the nZVI-FSBC can be considered as potential adsorbents to remove Cr(VI) for environment remediation.

A Facile Strategy to Fabricate Nanoscale Zero-Valent Iron Decorated Graphene Oxide Composite for Dechloridation of Trichloroacetic Acid in Water

2018 ◽  
Vol 18 (12) ◽  
pp. 8252-8257 ◽  
Author(s):  
Huixuan Zhang ◽  
Xinyi Zhang ◽  
Ruonan Guo ◽  
Qingfeng Cheng ◽  
Xiuwen Cheng
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Sewage Treatment ◽  
Reduction Process ◽  
Zero Valent Iron ◽  
Chlorinated Organic Compounds ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Adsorption Desorption

In this study, nanoscale zero-valent iron decorated graphene oxide (NZVI/GO) composite was fabricated through a reduction process in the presence of sodium borohydride (NaBH4) solution. Subsequently, physicochemical properties of the NZVI/GO composites were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR) and Raman spectra. Results indicated that Fe species existed in the form of Fe0, which uniformly dispersed on the surface of GO. Furthermore, the performance of NZVI/GO was evaluated by the degradation of tichloroacetic acid (TCAA). TCAA can be rapidly degraded by NZVI/GO. This paper provides a promising strategy to synthesize versatile catalyst which would be potentially applied in sewage treatment to degrade chlorinated organic compounds.

scholarly journals INVESTIGATION OF REMOVAL OF HEXAVALENT CHROMIUM AND DIVALENT COBALT FROM AQUEOUS SOLUTIONS BY ORGANO-MONTMORILLONITE SUPPORTED IRON NANOPARTICLES

2016 ◽  
Vol 5 ◽  
pp. 81-88 ◽  
Author(s):  
Viktoriia Prus ◽  
Nataliya Zhdanyuk
Keyword(s):  
Environmental Remediation ◽  
Iron Nanoparticles ◽  
Removal Rate ◽  
Environmental Pollutants ◽  
Zero Valent Iron ◽  
Hexadecyltrimethylammonium Bromide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanoscale Zero Valent Iron ◽  
Supported Iron

A new class of nanoscale zero-valent iron particles supported on natural montmorillonite and organo-montmorillonite were synthesized and the feasibility for the removal of and was examined through laboratory batch test. The X – ray diffraction (XRD) and Fourier Transform Infrared spectrum (FTIR) investigation has been applied for determination of the particle size and mechanism of remediation process. The aim of this study was to enhance the reduction of persistent environmental pollutants difficult to degrade by immobilization of nanoscale zero-valent iron on an organo-montmorillonite. Batch experiments indicated that the reduction of both and was much greater with organo-montmorillonite supported iron nanoparticles reaching removal rate up to 98.5% and 95.6% respectively at the initial metal concentrations of 50 mg/L. Iron and crystalline iron oxide were detected by X-ray diffraction patterns. In the FTIR spectrum, CH2 groups were found in iron nanoparticles supported on hexadecyltrimethylammonium bromide modified montmorillonite (HDTMA-Mont/nZVI) particles but were significantly weakened in comparison with the spectrum of hexadecyl trimethylammonium bromide (HDTMA). Other factor that affects the efficiency of heavy metals removal such as pH values was also investigated. The obtained data and review of the current literature have given the opportunity to figure out the mechanisms of and removal which may thus promote the industrial application of nZVI technique in environmental remediation by changing the hydrophilic – hydrophobic properties of source systems.

scholarly journals Phosphate adsorption onto bagasse iron oxide biochar: Parameter optimization, kinetic analysis, and study of mechanism

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1335-1357
Author(s):  
Qing Zhang ◽  
Yan-mei Ding ◽  
Lin Lu ◽  
Jing-xi Li ◽  
Mei-na Liang ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Phosphate Adsorption ◽  
Phosphorus Concentration ◽  
X Ray Diffraction ◽  
Phosphorus Adsorption ◽  
X Ray ◽  
Bet Specific Surface Area ◽  
Ph Range

This study combined chemical ultrasonic modifications and microwave oven heating to prepare a novel adsorbent, bagasse iron oxide biochar, (BIBC) to remove phosphate from aqueous solutions. The characterization of BIBC was made by energy dispersive spectrometry (EDS), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses, and the mechanism of phosphorus adsorption on BIBC was researched by adsorption batch experiments with emphasis on pH, dosages of BIBC, initial phosphorus concentration, and adsorption time. The BIBC’s BET specific surface area and pore volumes were 81.94 m2 g−1 and 26.74 cm3 g−1, respectively. The pH for the optimal phosphorus adsorption by BIBC ranged from 5.0 to 7.0. The maximum adsorption capacities of phosphorus (according to the Langmuir model) were 3.62, 4.06, and 4.32 mg g-1 at temperatures of 25, 35, and 45 °C, respectively. Electrostatic interaction, surface adsorption of phosphorus on BIBC, and ion exchange were the main mechanisms of phosphorus adsorption. According to XPS results, Fe2p was involved in the adsorption reaction. The adsorption of phosphorus by BIBC is considered to be mainly chemical adsorption. The BIBC was stable under a pH range from 4.0 to 10.0 and secondary pollution did not result.

scholarly journals Hydrothermal Enhanced Nanoscale Zero-Valent Iron Activated Peroxydisulfate Oxidation of Chloramphenicol in Aqueous Solutions: Fe-Speciation Analysis and Modeling Optimization

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 131 ◽  
Author(s):  
Lie Yang ◽  
Hong Li ◽  
Jianming Xue ◽  
Liuyang He ◽  
Yongfei Ma ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Speciation Analysis ◽  
Zero Valent Iron ◽  
Quadratic Model ◽  
X Ray ◽  
Condition Optimization ◽  
Degradation Rates ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph

The efficiencies of the nanoscale zero-valent iron (nZVI) and hydrothermal and nZVI-heat activation of peroxydisulfate (PS) were studied for the decomposition of chloramphenicol (CAP) in aqueous solutions. The nZVI heat combined with activation of PS provided a significant synergistic effect. A central composite design (CCD) with response surface methodology (RSM) was employed to explore the influences of single parameter and interactions of selected variables (initial pH, PS concentration, nZVI and temperature) on degradation rates with the purpose of condition optimization. A quadratic model was established based on the experimental results with excellent correlation coefficients of 0.9908 and 0.9823 for R2 and R2adj. The optimized experimental condition for 97.12% CAP removal was predicted with the quadratic model as 15 mg/L, 0.5 mmol/L, 7.08 and 70 °C for nZVI dosage, PS, initial pH, and temperature, respectively. This study demonstrated the effectiveness of RSM for the modeling and prediction of CAP removal processes. In the optimal condition, Fe2O3 and Fe3O4 were the predominant solid products after reactions based on X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis, which could also act as the activators along with the reaction. Overall, it could be concluded that hydrothermal enhanced nZVI activation of PS was a promising and efficient choice for CAP degradation.

scholarly journals Facile Production of a Fenton-Like Photocatalyst by Two-Step Calcination with a Broad pH Adaptability

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 676
Author(s):  
Siyang Ji ◽  
Yanling Yang ◽  
Xing Li ◽  
Hang Liu ◽  
Zhiwei Zhou
Keyword(s):  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Active Oxygen Species ◽  
Oxygen Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Ph Range ◽  
Calcination Method ◽  
Ph Range

A novel heterogeneous Fenton-like photocatalyst, Fe-doped graphitic carbon nitride (Fe-g-C3N4), was produced by facile two-step calcination method. This Fe–g–C3N4 catalyzed rhodamine B degradation in the presence of H2O2 accompanied with visible light irradiation. transmission electron microscopy(TEM), x-ray diffraction (XRD), FT-IR, x-ray photoelectron spectroscopy (XPS), and photoluminescence fluorescent spectrometer (PL) characterization analysis methods were adopted to evaluate the physicochemical property of samples. It can be observed that the Fe-g-C3N4 exhibited excellent photocatalytic Fenton-like activity at a wide pH range of 3–9, with rhodamine B(RhB) degradation efficiency up to 95.5% after irradiation for 45 min in the presence of 1.0 mM H2O2. Its high activity was ascribed to the formation of Fe–N ligands in the triazine rings that accelerated electron movement driving the Fe(III)/Fe(II) redox cycle, and inhibited photo-generated electron hole re-combinations for continuous generation of reactive oxygen species by reactions between Fe(II) and H2O2. The main active oxygen species were hydroxyl radicals, followed by superoxide radicals and hole electrons. This produced catalyst of Fe–g–C3N4 shows excellent reusability and stability, and can be a promising candidate for decontamination of wastewater.

Preparation, Characterization of Nanoscale Zero-Valent Iron and its Application in Coking Wastewater Treatment

2011 ◽  
Vol 194-196 ◽  
pp. 511-514
Author(s):  
Xue Zhang ◽  
Su Qin Li ◽  
Kudureti Ayijamali
Keyword(s):  
Wastewater Treatment ◽  
Chemical Reactivity ◽  
Zero Valent Iron ◽  
Coking Wastewater ◽  
Iron Particles ◽  
X Ray Diffraction ◽  
Adsorption Ability ◽  
Phase Reduction ◽  
Nanoscale Zero Valent Iron

As a new kind of materials, nanoscale zero-valent iron which had excellent adsorption ability and high chemical reactivity had been widely applied in advanced wastewater treatment. In this paper, the preparation of nanoscale zero-valent iron particles was liquid phase reduction ,and then iron nanoparticles were characterized by scanning electron microscope and X-ray diffraction. Also the application of nanoscale zero-valent iron in the difficult degradation coking wastewater treatment was discussed.

scholarly journals Activity and Stability of Trypsin Immobilized onto Chitosan Magnetic Nanoparticles

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Jun Sun ◽  
Bin Xu ◽  
Yu Shi ◽  
Lin Yang ◽  
Hai-le Ma
Keyword(s):  
Magnetic Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Covalent Immobilization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Immobilized Trypsin ◽  
Alkaline Conditions ◽  
Ph Range ◽  
Average Size

The aim of this study was to develop a thermally and operationally stable trypsin through covalent immobilization onto chitosan magnetic nanoparticles (Fe3O4 @CTS). The successful preparation of the Fe3O4 @CTS nanoparticles was verified by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM), which indicated that the prepared Fe3O4 @CTS nanoparticles have superparamagnetic properties, with an average size of approximately 17 nm. Then, trypsin was covalently immobilized onto the Fe3O4 @CTS nanoparticles at a high loading capacity (149.25 mg/g). The FTIR data demonstrated that the trypsin had undergone a conformational change compared with free trypsin, and the Michaelis constant (Km) and the maximum hydrolysis reaction rate (Vmax) showed that the trypsin immobilized on the Fe3O4 @CTS had a lower affinity for BAEE and lower activity compared with free trypsin. However, the immobilized trypsin showed higher activity than free trypsin at pH 6.0 and in alkaline conditions and retained more than 84% of its initial activity at 60°C after 8 h incubation. Its excellent performance across a broader pH range and high thermal stability, as well as its effective hydrolysis of bovine serum albumin (BSA) and its reusability, make it more attractive than free trypsin for application in protein digestion.

scholarly journals Application of CuxO-FeyOz Nanocatalysts in Ethynylation of Formaldehyde

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1301 ◽  
Author(s):  
Li ◽  
Ban ◽  
Niu ◽  
Huang ◽  
Meng ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Species ◽  
Sodium Ascorbate ◽  
Composite Nanomaterials ◽  
Heterogeneous Structure ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phase Reduction ◽  
Temperature Programmed

Composite nanomaterials have been widely used in catalysis because of their attractive properties and various functions. Among them, the preparation of composite nanomaterials by redox has attracted much attention. In this work, pure Cu2O was prepared by liquid phase reduction with Cu(NO3)2 as the copper source, NaOH as a precipitator, and sodium ascorbate as the reductant. With Fe(NO3)3 as the iron source and solid-state phase reaction between Fe3+ and Cu2O, CuxO-FeyOz nanocatalysts with different Fe/Cu ratios were prepared. The effects of the Fe/Cu ratio on the structure of CuxO-FeyOz nanocatalysts were studied by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet confocal Raman (Raman), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS, XAES), and hydrogen temperature-programmed reduction (H2-TPR). Furthermore, the structure–activity relationship between the structure of CuxO-FeyOz nanocatalysts and the performance of formaldehyde ethynylation was discussed. The results show that Fe3+ deposited preferentially on the edges and corners of the Cu2O surface, and a redox reaction between Fe3+ and Cu+ occurred, forming CuxO-FeyOz nanoparticles containing Cu+, Cu2+, Fe2+, and Fe3+. With the increase of the Fe/Cu ratio, the content of CuxO-FeyOz increased. When the Fe/Cu ratio reached 0.8, a core–shell structure with Cu2O inside and a CuxO-FeyOz coating on the outside was formed. Because of the large physical surface area and the heterogeneous structure formed by CuxO-FeyOz, the formation of nonactive Cu metal is inhibited, and the most active species of Cu+ are exposed on the surface, showing the best formaldehyde ethynylation activity.

Mechanism of Cu2+ Ions Removal from Aqueous Solution with PBTCA Modified Fe0 Nanoparticles

2014 ◽  
Vol 522-524 ◽  
pp. 454-457
Author(s):  
Jing Wei Feng ◽  
Ying Xia Xu
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Aqueous Media ◽  
Zero Valent Iron ◽  
Borohydride Reduction ◽  
Experimental Conditions ◽  
Redox Mechanism ◽  
X Ray ◽  
Nanoscale Zero Valent Iron

Applications of PBTCA modified nanoscale zero valent iron (P-Fe0) prepared by borohydride reduction for removal of Cu2+ions from aqueous solution are investigated under a variety of experimental conditions. According to X-ray photoelectron spectroscopy (XPS) results, Cu2+ions were removed primarily via a redox mechanism that resulted in the formation of Cu0and Cu2O. The contact of P-Fe0with aqueous media caused extensive formation of iron oxide.

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