Nano ZVI particles supported on micro-scale exfoliated graphite were prepared by using KBH4 as reducing agent in the H2O/ethanol system. The supported ZVI materials generally have higher activity and greater flexibili...Nano ZVI particles supported on micro-scale exfoliated graphite were prepared by using KBH4 as reducing agent in the H2O/ethanol system. The supported ZVI materials generally have higher activity and greater flexibility for environmental remediation applications. The exfoliated graphite as the support was treated beforehand to hydrophilic material. Nano iron particles are deposited onto the rough graphite surface while those were formed by borohydride reduction. The possible nitrate reduction pathways were proposed. The TEM image shows that iron particles are highly dispersed on the surface of graphite and several of iron particles are imbedded in the pit of support surface. In this synthesis, iron particles have a nearly spherical shape with a grain size of 50?100 nm. The surface areas of materials with different iron loadings of 3.5%, 7.0%, 10.0%, 15.0% and 20.0%(mass fraction) are 2.89, 9.55, 8.45, 23.8 and 6.18 m2·g?1 by BET surface analyzer. The chemical reduction of nitrate by supported nano ZVI in aqueous solution were tested in series batch experiments. Experiment results suggest that NO3? can be more rapidly reduced to NH4+ at neutral pH and anaerobic conditions by supported nano ZVI than unsupported nano ZVI or ZVI scraps. The 15% nano Fe/graphite shows the best reduction efficiency contrasted with other Fe loading particles.展开更多
In this study, iron nano-particles were used to remediate malathion contaminated soil in the concentration range of 1 - 10 μg?g–1. The zero valent iron nano-particles were prepared by reducing ferric chloride soluti...In this study, iron nano-particles were used to remediate malathion contaminated soil in the concentration range of 1 - 10 μg?g–1. The zero valent iron nano-particles were prepared by reducing ferric chloride solution with sodium boro- hydride for remediation of the soil. The optimized quantity of iron nano particles was found to be 0.1 g?kg–1 of soil con- taminated with 10 μg?g–1 of malathion. Malathion was determined in the soil after leaching to water at pH 8.2 and fol- lowed by its oxidation with slight excess of N-bromosuccinimide (NBS). The unconsumed NBS was estimated by measuring the decrease in the color intensity of rhodamine B. Degradation product formed during the oxidation of ma-lathion by zero valent iron was monitored by the Attenuated Total Reflectance Fourier Transform Infrared Spectros- copy (ATR-FTIR). The results clearly showed that quantitative oxidation of malathion was achieved within eight min- utes after the addition of zero valent iron nano particles.展开更多
In this study, novel core-shell SiO<sub>2</sub>-coated iron nanoparticles (SiO<sub>2</sub>-nZVI) were synthesized using a one-step Stoeber method. The Malachite green degradation abilities of t...In this study, novel core-shell SiO<sub>2</sub>-coated iron nanoparticles (SiO<sub>2</sub>-nZVI) were synthesized using a one-step Stoeber method. The Malachite green degradation abilities of the nanoparticles were investigated. The effects of ethanol/distilled water volume ratio, presence and absence of PEG, tetraethyl orthosilicate (TEOS) dosage, and hydrolysis time used in the nanoparticles preparation process were investigated. The results indicated that the SiO<sub>2</sub>-coated iron nanoparticles had the highest reduction activity when the particles synthesized with ethanol/H<sub>2</sub>O ratio of 2:1, PEG of 0.15 ml, TEOS of 0.5 ml and the reaction time was 4 h. The SiO<sub>2</sub>-nZVI nanoparticles were characterized using Transmission Electron Microscopy (TEM), Energy Dispersive Spectrometry (EDS) and powder X-Ray Diffraction (XRD). The results showed that the average particles diameter of the SiO<sub>2</sub>-nZVI was 20 - 30 nm. The thickness of the outside SiO<sub>2</sub> film is consistent and approximately 10 nm. The results indicated that the nanoparticles coated completely with a transparent SiO<sub>2</sub>-film. Such nanoparticles could have wide applications in dye decolorization.展开更多
Risk associated with heavy metals in soil has been received widespread attention.In this study,a porous biochar supported nanoscale zero-valent iron(BC-nZVI)was applied to immobilize cadmium(Cd)and lead(Pb)in clayey s...Risk associated with heavy metals in soil has been received widespread attention.In this study,a porous biochar supported nanoscale zero-valent iron(BC-nZVI)was applied to immobilize cadmium(Cd)and lead(Pb)in clayey soil.Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process,and about 80%of heavy metals immobilization was obtained in BC-nZVI process.Addition of BC-nZVI could increase soil pH and organic matter(SOM).Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol(2,4-DCP),but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels.Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process,and both Cd and Pb availability significantly decreased.Stable Cd species inculding Cd(OH)_(2),CdCO_(3)and CdO were formed,whereas stable Pb species such as PbCO_(3),PbO and Pb(OH)_(2)were produced with BC-nZVI treatment.Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed.This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple heavy metals in soil.展开更多
Toxicity studies considering both the bare and stabilized forms of zero valent iron nanoparticles（nZVI） could be timely, given that ecological risks identified are minimized through modification or with substitution...Toxicity studies considering both the bare and stabilized forms of zero valent iron nanoparticles（nZVI） could be timely, given that ecological risks identified are minimized through modification or with substitution of approaches in the synthesis, development and environmental application of the nanoparticles before succeeding to volume production.This review is focused on the fate, transport and toxicological implications of the bare nZVI and surface modified particles used for environmental applications.展开更多
Nanoscale zero-valent iron （NZVI） is considered to have potential to reduce nitrate in the concentrate generated by high pressure membrane processes aimed at water reuse. However, it is necessary to verify the effec...Nanoscale zero-valent iron （NZVI） is considered to have potential to reduce nitrate in the concentrate generated by high pressure membrane processes aimed at water reuse. However, it is necessary to verify the effect of the matrix components in the concentrates on NZVI reactivity. In this study, the influence of hardness, alkalinity, and organic matter on NZVI reactivity was evaluated by the response surface method （RSM）. Hardness （Ca/＋） had a positive effect on NZVI reactivity by accelerating iron corrosion. In contrast, alkalinity （bicarbonate; HCO3） and organic matter （humic acid; HA） had negative effects on NZVI reactivity due to morphological change to carbonate green rust, and to competitive adsorption of HA, respectively. The validity of the statistical prediction model derived from RSM was confirmed by an additional confirmation experiment, and the experimental result was within the 95% confidential interval. Therefore, it can be indicated that the RSM model produced results that were statistically significant.展开更多
基金Project(20477019) supported by the National Natural Science Foundation of China
文摘Nano ZVI particles supported on micro-scale exfoliated graphite were prepared by using KBH4 as reducing agent in the H2O/ethanol system. The supported ZVI materials generally have higher activity and greater flexibility for environmental remediation applications. The exfoliated graphite as the support was treated beforehand to hydrophilic material. Nano iron particles are deposited onto the rough graphite surface while those were formed by borohydride reduction. The possible nitrate reduction pathways were proposed. The TEM image shows that iron particles are highly dispersed on the surface of graphite and several of iron particles are imbedded in the pit of support surface. In this synthesis, iron particles have a nearly spherical shape with a grain size of 50?100 nm. The surface areas of materials with different iron loadings of 3.5%, 7.0%, 10.0%, 15.0% and 20.0%(mass fraction) are 2.89, 9.55, 8.45, 23.8 and 6.18 m2·g?1 by BET surface analyzer. The chemical reduction of nitrate by supported nano ZVI in aqueous solution were tested in series batch experiments. Experiment results suggest that NO3? can be more rapidly reduced to NH4+ at neutral pH and anaerobic conditions by supported nano ZVI than unsupported nano ZVI or ZVI scraps. The 15% nano Fe/graphite shows the best reduction efficiency contrasted with other Fe loading particles.
文摘In this study, iron nano-particles were used to remediate malathion contaminated soil in the concentration range of 1 - 10 μg?g–1. The zero valent iron nano-particles were prepared by reducing ferric chloride solution with sodium boro- hydride for remediation of the soil. The optimized quantity of iron nano particles was found to be 0.1 g?kg–1 of soil con- taminated with 10 μg?g–1 of malathion. Malathion was determined in the soil after leaching to water at pH 8.2 and fol- lowed by its oxidation with slight excess of N-bromosuccinimide (NBS). The unconsumed NBS was estimated by measuring the decrease in the color intensity of rhodamine B. Degradation product formed during the oxidation of ma-lathion by zero valent iron was monitored by the Attenuated Total Reflectance Fourier Transform Infrared Spectros- copy (ATR-FTIR). The results clearly showed that quantitative oxidation of malathion was achieved within eight min- utes after the addition of zero valent iron nano particles.
文摘In this study, novel core-shell SiO<sub>2</sub>-coated iron nanoparticles (SiO<sub>2</sub>-nZVI) were synthesized using a one-step Stoeber method. The Malachite green degradation abilities of the nanoparticles were investigated. The effects of ethanol/distilled water volume ratio, presence and absence of PEG, tetraethyl orthosilicate (TEOS) dosage, and hydrolysis time used in the nanoparticles preparation process were investigated. The results indicated that the SiO<sub>2</sub>-coated iron nanoparticles had the highest reduction activity when the particles synthesized with ethanol/H<sub>2</sub>O ratio of 2:1, PEG of 0.15 ml, TEOS of 0.5 ml and the reaction time was 4 h. The SiO<sub>2</sub>-nZVI nanoparticles were characterized using Transmission Electron Microscopy (TEM), Energy Dispersive Spectrometry (EDS) and powder X-Ray Diffraction (XRD). The results showed that the average particles diameter of the SiO<sub>2</sub>-nZVI was 20 - 30 nm. The thickness of the outside SiO<sub>2</sub> film is consistent and approximately 10 nm. The results indicated that the nanoparticles coated completely with a transparent SiO<sub>2</sub>-film. Such nanoparticles could have wide applications in dye decolorization.
基金supported by the Special project in key areas of Guangdong Province Ordinary Universities (No. 2020ZDZX1003)the Guangdong Provincial Key R&D Programme (No. 2020B1111350002)+4 种基金the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2018)the research project and development plan for key areas of Guangdong Province (No. 2020B0202080002)the Project of Educational Commission of Guangdong Province of China (No. 2019KTSCX067)the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (No. 2019KJ140)the National Natural Science Foundation of China (No. 21407155).
文摘Risk associated with heavy metals in soil has been received widespread attention.In this study,a porous biochar supported nanoscale zero-valent iron(BC-nZVI)was applied to immobilize cadmium(Cd)and lead(Pb)in clayey soil.Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process,and about 80%of heavy metals immobilization was obtained in BC-nZVI process.Addition of BC-nZVI could increase soil pH and organic matter(SOM).Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol(2,4-DCP),but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels.Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process,and both Cd and Pb availability significantly decreased.Stable Cd species inculding Cd(OH)_(2),CdCO_(3)and CdO were formed,whereas stable Pb species such as PbCO_(3),PbO and Pb(OH)_(2)were produced with BC-nZVI treatment.Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed.This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple heavy metals in soil.
文摘Toxicity studies considering both the bare and stabilized forms of zero valent iron nanoparticles（nZVI） could be timely, given that ecological risks identified are minimized through modification or with substitution of approaches in the synthesis, development and environmental application of the nanoparticles before succeeding to volume production.This review is focused on the fate, transport and toxicological implications of the bare nZVI and surface modified particles used for environmental applications.
基金supported by the Program for the Construction of Eco Industrial Park, which was conducted by the Korea Industrial Complex Corporation and the Ministry of Knowledge Economyfinancially supported by the National Research Foundation of Korea grant funded by the Korea government Ministry of Education, Science and Technology (NRF2012M1A2A2026587)
文摘Nanoscale zero-valent iron （NZVI） is considered to have potential to reduce nitrate in the concentrate generated by high pressure membrane processes aimed at water reuse. However, it is necessary to verify the effect of the matrix components in the concentrates on NZVI reactivity. In this study, the influence of hardness, alkalinity, and organic matter on NZVI reactivity was evaluated by the response surface method （RSM）. Hardness （Ca/＋） had a positive effect on NZVI reactivity by accelerating iron corrosion. In contrast, alkalinity （bicarbonate; HCO3） and organic matter （humic acid; HA） had negative effects on NZVI reactivity due to morphological change to carbonate green rust, and to competitive adsorption of HA, respectively. The validity of the statistical prediction model derived from RSM was confirmed by an additional confirmation experiment, and the experimental result was within the 95% confidential interval. Therefore, it can be indicated that the RSM model produced results that were statistically significant.
