The zero-valent iron modified biochar materials are widely employed for heavy metals immobilization.However,these materials would be inevitably aged by natural forces after entering into the environment,while there ar...The zero-valent iron modified biochar materials are widely employed for heavy metals immobilization.However,these materials would be inevitably aged by natural forces after entering into the environment,while there are seldom studies reported the aging effects of zero-valent iron modified biochar.In this work,the hydrogen peroxide and hydrochloric acid solution were applied to simulate aging conditions of zero-valent iron modified biochar.According to the results,the adsorption capacity of copper(II)contaminants on biochar,zero-valent iron modified biochar-1,and zero-valent iron modified biochar-2 after aging was decreased by 15.36%,22.65%and 23.26%,respectively.The surface interactions were assigned with chemisorption occurred on multi-molecular layers,which were proved by the pseudo-second-order and Langmuir models.After aging,the decreasing of capacity could be mainly attributed to the inhibition of ion-exchange and zero-valent iron oxidation.Moreover,the plant growth and soil leaching experiments also proved the effects of aging treatment,the zero-valent iron modified biochar reduced the inhibition of copper(II)bioavailability and increased the mobility of copper(II)after aging.All these results bridged the gaps between bio-adsorbents customization and their environmental behaviors during practical agro-industrial application.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
Zero-valent iron(ZVI),an ideal reductant treating persistent pollutants,is hampered by issues like corrosion,passivation,and suboptimal utilization.Recent advancements in nonmetallic modified ZVI(NM-ZVI)show promising...Zero-valent iron(ZVI),an ideal reductant treating persistent pollutants,is hampered by issues like corrosion,passivation,and suboptimal utilization.Recent advancements in nonmetallic modified ZVI(NM-ZVI)show promising potential in circumventing these challenges by modifying ZVI's surface and internal physicochemical properties.Despite its promise,a thorough synthesis of research advancements in this domain remains elusive.Here we review the innovative methodologies,regulatory principles,and reduction-centric mechanisms underpinning NM-ZVI's effectiveness against two prevalent persistent pollutants:halogenated organic compounds and heavy metals.We start by evaluating different nonmetallic modification techniques,such as liquid-phase reduction,mechanical ball milling,and pyrolysis,and their respective advantages.The discussion progresses towards a critical analysis of current strategies and mechanisms used for NM-ZVI to enhance its reactivity,electron selectivity,and electron utilization efficiency.This is achieved by optimizing the elemental compositions,content ratios,lattice constants,hydrophobicity,and conductivity.Furthermore,we propose novel approaches for augmenting NM-ZVI's capability to address complex pollution challenges.This review highlights NM-ZVI's potential as an alternative to remediate water environments contaminated with halogenated organic compounds or heavy metals,contributing to the broader discourse on green remediation technologies.展开更多
基金The authors appreciate the support from the National Natural Science Foundation of China(Grant No.22264025)the Yunnan Province Education Department Scientific Research Foundation Project(Grant No.2022J0136)the Applied Basic Research Foundation of Yunnan Province(Grant Nos.202201AS070020,202201AU070061).
文摘The zero-valent iron modified biochar materials are widely employed for heavy metals immobilization.However,these materials would be inevitably aged by natural forces after entering into the environment,while there are seldom studies reported the aging effects of zero-valent iron modified biochar.In this work,the hydrogen peroxide and hydrochloric acid solution were applied to simulate aging conditions of zero-valent iron modified biochar.According to the results,the adsorption capacity of copper(II)contaminants on biochar,zero-valent iron modified biochar-1,and zero-valent iron modified biochar-2 after aging was decreased by 15.36%,22.65%and 23.26%,respectively.The surface interactions were assigned with chemisorption occurred on multi-molecular layers,which were proved by the pseudo-second-order and Langmuir models.After aging,the decreasing of capacity could be mainly attributed to the inhibition of ion-exchange and zero-valent iron oxidation.Moreover,the plant growth and soil leaching experiments also proved the effects of aging treatment,the zero-valent iron modified biochar reduced the inhibition of copper(II)bioavailability and increased the mobility of copper(II)after aging.All these results bridged the gaps between bio-adsorbents customization and their environmental behaviors during practical agro-industrial application.
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 NSFC-JSPS joint research program(No.51961145202)the National Natural Science Foundation of China(No.52370163,52321005,and 52293443)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2022TS42).
文摘Zero-valent iron(ZVI),an ideal reductant treating persistent pollutants,is hampered by issues like corrosion,passivation,and suboptimal utilization.Recent advancements in nonmetallic modified ZVI(NM-ZVI)show promising potential in circumventing these challenges by modifying ZVI's surface and internal physicochemical properties.Despite its promise,a thorough synthesis of research advancements in this domain remains elusive.Here we review the innovative methodologies,regulatory principles,and reduction-centric mechanisms underpinning NM-ZVI's effectiveness against two prevalent persistent pollutants:halogenated organic compounds and heavy metals.We start by evaluating different nonmetallic modification techniques,such as liquid-phase reduction,mechanical ball milling,and pyrolysis,and their respective advantages.The discussion progresses towards a critical analysis of current strategies and mechanisms used for NM-ZVI to enhance its reactivity,electron selectivity,and electron utilization efficiency.This is achieved by optimizing the elemental compositions,content ratios,lattice constants,hydrophobicity,and conductivity.Furthermore,we propose novel approaches for augmenting NM-ZVI's capability to address complex pollution challenges.This review highlights NM-ZVI's potential as an alternative to remediate water environments contaminated with halogenated organic compounds or heavy metals,contributing to the broader discourse on green remediation technologies.
