Abstract
FeS nanoparticles were synthesized using chemical precipitation method involving sulfide and ferrous solutions. Effects of important synthesis parameters including stabilizer, time taken for titration, horizontal oscillation speed, and initial salt concentration on the size of synthesized FeS nanoparticles were investigated by Orthogonal Array design. Increasing the CMC dosage significantly made the hydrodynamic diameter decrease between 0.05 wt.% and 0.15 wt.% while Na2S titration, oscillation rate, and Na2S concentration did not show significant influence on the hydrodynamic diameter of FeS nanoparticles. The synthesized FeS nanoparticles were characterized by using XRD (X-ray diffraction), TEM (transmission electron microscopy), and XPS (X-ray photoelectron spectroscopy). The as-synthesized FeS nanoparticles had an average size of 25 ± 10 nm and had a better long-term stability after storage for 150 days compared to bare FeS particles. Because of the optimized process parameters, the synthesized FeS nanoparticles had a higher Cr(VI) removal capacity of 683 mg per gram of FeS in comparison to the previously reported cases, and up to 92.48% Cr(VI) was removed from aqueous solutions. The small size, special surface property, and high reactivity make the synthesized FeS nanoparticles a promising tool for the remediation of Cr(VI) contaminated soil and groundwater.
Highlights
Nanomaterials have become one of the most promising materials to solve different problems in the various demanding fields [1,2,3,4,5]; in particular sulfur containing nanomaterials have been applied extensively in dechlorination of tetrachloroethene [6], cathode material for lithium batteries [7], catalytic applications [8], electrochemical DNA detection analysis [9], and so on
Stabilizer, time taken for titration, horizontal oscillation speed, and initial salt concentration were selected as the input factors in 3-level orthogonal tests in order to screen the key factors and optimize the synthesis conditions, and the ranges
Our finding shows that the optimal synthesis conditions were CMC dosage at 0.15 wt.%, oscillation rate at 250 rpm, titration speed at 0.05 mL/s, and Na2S concentration at 0.0426 M
Summary
Nanomaterials have become one of the most promising materials to solve different problems in the various demanding fields [1,2,3,4,5]; in particular sulfur containing nanomaterials have been applied extensively in dechlorination of tetrachloroethene [6], cathode material for lithium batteries [7], catalytic applications [8], electrochemical DNA detection analysis [9], and so on. The size, shape, and other properties of those metal sulfide nanomaterials, which determined their applications, were greatly influenced by the synthesis methods and conditions [14,15,16]. FeS nanotubes [17], FeS nanosheets [18, 19], and Fe/FeS nanoparticles [20] are synthesized with various methods such as sulfurization of hematite, solvothermal synthesis, soft-template method, and chemical reduction. During these processes, the frequent usage of toxic gases (H2S), complicated reactions, and unsafe reagents restricts their selection. The long-term stability of the nanoparticles may influence the effectiveness of their utilization as a remediation reagent; the specific knowledge on how the synthesis process
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