Enhanced removal efficiency of bromate from aqueous solutions by nanoscale zero-valent iron immobilized on activated carbon

2014 ◽  
Vol 54 (9) ◽  
pp. 2480-2489 ◽  
Author(s):  
Chunhua Xu ◽  
Xiaohong Wang ◽  
Sheng Lin ◽  
Liujia Zhu ◽  
Yaming Chen
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Removal Efficiency ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron

scholarly journals Adsorption of phosphorus onto nanoscale zero-valent iron/activated carbon: removal mechanisms, thermodynamics, and interferences

2022 ◽  
Author(s):  
Adel Adly ◽  
Nagwan G. Mostafa ◽  
Abdelsalam Elawwad
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Kinetic Models ◽  
Average Particle Size ◽  
Zero Valent Iron ◽  
Solution Temperature ◽  
Average Particle ◽  
Phosphorus Adsorption ◽  
Removal Mechanisms ◽  
Nanoscale Zero Valent Iron

Abstract This study investigated removal mechanisms, thermodynamics, and interferences of phosphorus adsorption onto nanoscale zero-valent iron (nZVI)/activated carbon composite. Activated carbon was successfully used as support for nZVI particles to overcome shortcomings of using nZVI include its tendency to aggregate and separation difficulties. A comprehensive characterization was done for the composite particles, which revealed a high specific surface area of 72.66 m2/g and an average particle size of 37 nm. Several adsorption isotherms and kinetic models have been applied to understand the removal mechanisms. Adsorption isotherm is best fitted by Freundlich and Langmuir models, which indicates that the estimated maximum phosphorus adsorption capacity is 53.76 mg/g at pH 4. Adsorption kinetics showed that the chemisorption process behaved according to a pseudo-second-order model. An adsorption mechanism study conducted using the intra-particle diffusion and Boyd kinetic models indicated that the adsorption rate is limited by surface diffusion. A thermodynamic study showed that phosphorus removal efficiency increased as the solution temperature increased from 15 to 37 °C. Finally, the results of an interference study showed that the presence of Ni2+, Cu2+, Ca2+, Na+ cations, nitrate ions (), and sodium acetate improves removal efficiency, while the presence of sulfate ions () and urea reduces removal efficiency.

Green Synthesis of Nanoscale Zero-Valent Iron/Activated Carbon Composites and their Application for Copper and Chromium Removal from Aqueous Solutions

2021 ◽  
Vol 66 ◽  
pp. 129-142
Author(s):  
Fatemeh Afroosheh ◽  
Somayeh Bakhtiari ◽  
Meysam Shahrashoub ◽  
Majid Ebrahimi
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Green Tea ◽  
Low Cost ◽  
Green Tea Extract ◽  
Zero Valent Iron ◽  
Spherical Particles ◽  
Green Approach ◽  
Nanoscale Zero Valent Iron ◽  
Tea Extract

In this study, nanoscale zero-valent iron (nZVI) particles and their composites with powdered activated carbon (nZVI-PAC) and granular activated carbon (nZVI-GAC) were successfully synthesized via a low-cost green approach with the use of green tea extract. The adsorbents were then used to remove Cr and Cu from aqueous solutions, and their adsorption results were fitted with the Freundlich and Langmuir models. The synthesized adsorbents were characterized using XRD, FTIR, and FESEM techniques. The typical peak of Fe0 was detected in the XRD patterns of prepared samples, but the presence of organic compounds in green tea extract weakened related peak. The FESEM characterization demonstrated that the nZVI spherical particles had a chain-like structure and ranging in size from 10 to 50nm. The presence of polyphenols peak in the FTIR spectra revealed that the green tea extract was responsible for the reduction of the Fe2+ to Fe0. The maximum adsorbed amount of Cr and Cu was found to be 5.68 and 6.48 mg/g, which was achieved by nZVI-PAC and nZVI, respectively. The nZVI-PAC and nZVI also showed a higher removal efficiency for Cu and Cr by 62% and 94% for an initial concentration of 100 mg/L, respectively. The results showed that nZVI, nZVI-PAC, and nZVI-GAC could be promising and eco-friendly adsorbents for Cr and Cu removal from aqueous solutions.

scholarly journals Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment

2021 ◽  
Vol 18 (11) ◽  
pp. 5921
Author(s):  
Haiyan Song ◽  
Wei Liu ◽  
Fansheng Meng ◽  
Qi Yang ◽  
Niandong Guo
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Inhibitory Effect ◽  
Ultrasonic Cavitation ◽  
Zero Valent Iron ◽  
Ultrasonic Pretreatment ◽  
Nanoscale Zero Valent Iron ◽  
Passivation Layers ◽  
Initial Ph ◽  
Two Phases

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO42−, NO3−, and Cl− had a strong inhibitory effect on this process, while the presence of SO42− promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe2+ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe0 core was exposed, which improved the reactivity of the composites.

scholarly journals Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1417
Author(s):  
Min Zhuang ◽  
Wen Shi ◽  
Hui Wang ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Surface Passivation ◽  
Bimetallic Nanoparticles ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Particle Sizes ◽  
Iron Corrosion ◽  
Graphitized Carbon ◽  
Nanoscale Zero Valent Iron ◽  
Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

Removal of Ni(II) from aqueous solutions by sulfide-modified nanoscale zero-valent iron supported by hydroxyapatite(HAP/S-nZVI)

2021 ◽  
Vol 232 ◽  
pp. 149-164
Author(s):  
Hui Xu ◽  
Minzhang Chen ◽  
Yajuan Zhang ◽  
Pengdong Chen ◽  
Yong Chen
Keyword(s):  
Aqueous Solutions ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron

scholarly journals Effect of Kaolin particle size on the removal of Pb(II) from aqueous solutions by Kaolin-supported nanoscale zero-valent iron

2020 ◽  
Vol 7 (4) ◽  
pp. 045002
Author(s):  
Shang-Qun Li ◽  
Chuang Yu ◽  
Ze-Xiang Wu ◽  
Xiao-Qing Cai ◽  
Fu-Sheng Zha
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron

scholarly journals Highly efficient and rapid removal of arsenic(iii) from aqueous solutions by nanoscale zero-valent iron supported on a zirconium 1,4-dicarboxybenzene metal–organic framework (UiO-66 MOF)

RSC Advances ◽  
2019 ◽  
Vol 9 (67) ◽  
pp. 39475-39487 ◽  
Author(s):  
Tingyi Liu ◽  
Zhengchao Zhang ◽  
Zhaohui Wang ◽  
Zhong-Liang Wang ◽  
Richard Bush
Keyword(s):  
Aqueous Solutions ◽  
Metal Organic Framework ◽  
Zero Valent Iron ◽  
Highly Efficient ◽  
Nanoscale Zero Valent Iron ◽  
Metal Organic ◽  
Rapid Removal ◽  
Removal Of Arsenic ◽  
Organic Framework

A zirconium 1,4-dicarboxybenzene metal–organic framework (UiO-66 MOF) was successfully used as a template to enhance the distribution and activity of nanoscale zero-valent iron (NZVI).

scholarly journals Well-Dispersed Nanoscale Zero-Valent Iron Supported in Macroporous Silica Foams: Synthesis, Characterization, and Performance in Cr(VI) Removal

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Chaoxia Zhao ◽  
Jie Yang ◽  
Yihan Wang ◽  
Bo Jiang
Keyword(s):  
Removal Efficiency ◽  
Shell Structure ◽  
Zero Valent Iron ◽  
Core Shell ◽  
Ambient Atmosphere ◽  
Order Kinetic ◽  
Macroporous Silica ◽  
X Ray ◽  
Nanoscale Zero Valent Iron ◽  
Core Shell Structure

Well-dispersed nanoscale zero-valent iron (NZVI) supported inside the pores of macroporous silica foams (MOSF) composites (Mx-NZVI) has been prepared as the Cr(VI) adsorbent by simply impregnating the MOSF matrix with ferric chloride, followed by the chemical reduction with NaHB4 in aqueous solution at ambient atmosphere. Through the support of MOSF, the reactivity and stability of NZVI are greatly improved. Transmission electron microscopy (TEM) results show that NZVI particles are spatially well-dispersed with a typical core-shell structure and supported inside MOSF matrix. The N2 adsorption-desorption isotherms demonstrate that the Mx-NZVI composites can maintain the macroporous structure of MOSF and exhibit a considerable high surface area (503 m2·g−1). X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (XRD) measurements confirm the core-shell structure of iron nanoparticles composed of a metallic Fe0 core and an Fe(II)/Fe(III) species shell. Batch experiments reveal that the removal efficiency of Cr(VI) can reach 100% when the solution contains 15.0 mg·L−1 of Cr(VI) at room temperature. In addition, the solution pH and the composites dosage can affect the removal efficiency of Cr(VI). The Langmuir isotherm is applicable to describe the removal process. The kinetic studies demonstrate that the removal of Cr(VI) is consistent with pseudo-second-order kinetic model.

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