The Influence of Pluronic F-127 Modification on Nano Zero-Valent Iron (NZVI): Sedimentation and Reactivity with 2,4-Dichlorophenol in Water Using Response Surface Methodology

Nano zero-valent iron (NZVI) is widely used for reducing chlorinated organic pollutants in water. However, the stability of the particles will affect the removal rate of the contaminant. In order to enhance the stability of nano zero-valent iron (NZVI), the particles were modified with F-127 as an environmentally friendly organic stabilizer. The study investigated the effect of the F-127 mass ratio on the colloidal stability of NZVI. Results show that the sedimentation behavior of F-NZVI varied at different mass ratios. A biphasic model was used to describe the two time-dependent settling processes (rapid sedimentation followed by slower settling), and the settling rates were calculated. The surface morphology of the synthesized F-NZVI was observed with a scanning electron microscope (SEM), and the functional groups of the samples were analyzed with Fourier Transform Infrared Spectroscopy (FTIR). Results show that the F-127 was successfully coated on the surface of the NZVI, and that significantly improved the stability of NZVI. Finally, in order to optimize the removal rate of 2,4-dichlorophenol (2,4-DCP) by F-NZVI, three variables were tested: the initial concentration 2,4-DCP, the pH, and the F-NZVI dosage. These were evaluated with a Box-Behnken Design (BBD) of response surface methodology (RSM). The experiments were designed by Design Expert software, and the regression model of fitting quadratic model was established. The following optimum removal conditions were determined: pH = 5, 3.5 g·L−1 F-NZVI for 22.5 mg·L−1 of 2,4-DCP.

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Removal of benzotriazole by Photo-Fenton like process using nano zero-valent iron: response surface methodology with a Box-Behnken design

Polish Journal of Chemical Technology ◽

10.1515/pjct-2017-0015 ◽

2017 ◽

Vol 19 (1) ◽

pp. 104-112 ◽

Cited By ~ 10

Author(s):

Mehdi Ahmadi ◽

Kurosh Rahmani ◽

Ayat Rahmani ◽

Hasan Rahmani

Keyword(s):

Response Surface Methodology ◽

Electron Microscope ◽

Response Surface ◽

Sem Analysis ◽

Zero Valent Iron ◽

X Ray Diffraction ◽

Box Behnken Design ◽

Transmission Electron ◽

Nano Zero Valent Iron ◽

Good Agreement

Abstract In this paper, the removal of benzotriazole (BTA) was investigated by a Photo-Fenton process using nano zero valent iron (NZVI) and optimization by response surface methodology based on Box-Behnken method. Effect of operating parameters affecting removal efficiency such as H2O2, NZVI, and BTA concentrations as well as pH was studied. All the experiments were performed in the presence of ultraviolet radiation. Predicted levels and BTA removal were found to be in good agreement with the experimental levels (R2 = 0. 9500). The optimal parameters were determined at 60 min reaction time, 15 mg L-1 BTA, 0.10 g L-1 NZVI, and 1.5 mmol L-1 H2O2 for Photo-Fenton-like reaction. NZVI was characterized using X-ray diffraction (XRD), transmission electron microscope (TEM) images, and scanning electron microscope (SEM) analysis.

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Size Distribution and Phosphate Removal Capacity of Nano Zero-Valent Iron (nZVI): Influence of pH and Ionic Strength

Water ◽

10.3390/w12102939 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2939

Author(s):

Dantong Lin ◽

Liming Hu ◽

Irene M. C. Lo ◽

Zhigang Yu

Keyword(s):

Ionic Strength ◽

Size Distribution ◽

Environmental Conditions ◽

Colloidal Stability ◽

Removal Rate ◽

Phosphate Removal ◽

Zero Valent Iron ◽

Removal Capacity ◽

Nano Zero Valent Iron ◽

Ph Conditions

Nano zero-valent iron (nZVI) has been considered as a promising material for groundwater remediation in the past few decades. The size distribution of nZVI is one of the main factors that influences its transport capability and remediation capacity. However, studies on the size distribution of nZVI under different environmental conditions are still limited. In this study, the influence of the pH (pH = 5, 7, 9) and ionic strength (IS = 0, 15, 30, 45 mM) on the size distribution of nZVI are investigated. The dynamic light scattering (DLS) method is used to study the variation of the size distribution of nZVI aggregate with time, and batch tests are performed to evaluate the efficiency of phosphate removal. Meanwhile, the phosphate removal capacity of nZVI with different size distribution was examined. Experimental results show that under low IS and high pH conditions, nZVI aggregate exhibited a stable, narrow and one-peak size distribution. By contrast, under high IS and low pH conditions, nZVI exhibited a wide and complicated size distribution with multiple peak values. This different pattern in size distribution was further explained by the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The phosphate removal rate of nZVI under acidic and neutral conditions is higher than 98% but is only 68% under alkaline conditions. The phosphate removal capacity is insensitive to the variation of IS since the removal rate is higher than 97% for different IS conditions. Favorable environmental conditions for colloidal stability and removal capacity of nZVI can be different, which needs comprehensive consideration in the application.

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Application of response surface methodology (RSM) for the removal of methylene blue dye from water by nano zero-valent iron (NZVI)

Water Science & Technology ◽

10.2166/wst.2016.122 ◽

2016 ◽

Vol 74 (2) ◽

pp. 343-352 ◽

Cited By ~ 10

Author(s):

Morteza Khosravi ◽

Simin Arabi

Keyword(s):

Methylene Blue ◽

Response Surface Methodology ◽

Response Surface ◽

Contact Time ◽

Dye Removal ◽

Water Solution ◽

Zero Valent Iron ◽

Blue Dye ◽

Methylene Blue Dye ◽

Nano Zero Valent Iron

In this study, iron zero-valent nanoparticles were synthesized, characterized and studied for removal of methylene blue dye in water solution. The reactions were mathematically described as the function of parameters such as nano zero-valent iron (NZVI) dose, pH, contact time and initial dye concentration, and were modeled by the use of response surface methodology. These experiments were carried out as a central composite design consisting of 30 experiments determined by the 24 full factorial designs with eight axial points and six center points. The results revealed that the optimal conditions for dye removal were NZVI dose 0.1–0.9 g/L, pH 3–11, contact time 20–100 s, and initial dye concentration 10–50 mg/L, respectively. Under these optimal values of process parameters, the dye removal efficiency of 92.87% was observed, which very close to the experimental value (92.21%) in batch experiment. In the optimization, R2 and R2adj correlation coefficients for the model were evaluated as 0.96 and 0.93, respectively.

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