Pursuit of optimal synthetic conditions for obtaining colloidal zero-valent iron nanoparticles by scanning pulsed laser ablation in liquids

Ruth Lahoz,Eva Natividad,Álvaro Mayoral,Christian Rentenberger,Daniel Díaz-Fernández,Eduardo J. Félix,Leonardo Soriano,Wolfgang Kautek,Oscar Bomati-Miguel 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

Liquid-Assisted Pulsed Laser Ablation (LA-PLA) is a promising top-down method to directly synthesizecolloidal dispersions of nanoparticles in a eco-friendly manner. However, the role of LA-PLA synthesisparameters is not yet fully agreed. This work seeks to optimize the production of nanoscale zero-valentiron (nZVI) particles suitable for biomedical or environmental applications using nanosecond LA-PLA oniron targets with different ablation media, laser and target scanning parameters. The use of alcohols assolvents produces iron-iron oxide core-shell nanoparticles with amorphous cores, except for a smallcrystalline fraction corresponding to the biggest core sizes. Decreasing carbon chain length andcomplexity leads to a thinning of the carbonaceous material coatings and an increase of the colloidalstability and the nanoparticle productivity. Moreover, a decrease of solvent density and surface tensionallows obtaining reduced sizes and polydispersity values. Among, laser and scanning parameters, thepulse accumulation per spot displayed a clear effect in boosting size and productivity. As main outcome,aqueous dispersions with suitable colloidal properties are obtained, either by transferring to water ofoptimized nZVI particles produced in ethanol, or by direct formation of nZVI particles and in situ coatingwith hydrophilic molecules in aqueous solutions of these molecules.

커피찌꺼기로 지지된 나노영가철을 이용한 폐수 중 납과 카드뮴 흡착

박만호,이가령,박현수,정상재,김재영 대한환경공학회 2018 대한환경공학회지 Vol.40 No.2

Nano zero valent iron (NZVI) is an emerging adsorbent for heavy metal removal with its high reactivity and reduction potential. However, NZVI tends to aggregate to bigger particles, thus surface area and reactivity could be decreased in applications. In this study, NZVI is synthesized while attached on coffee ground to prevent agglomeration. Then batch adsorption tests for Pb2+ and Cd2+ in wastewater were studied. Adsorption isotherm under pH 6 and 20℃ revealed that maximum adsorption capacity from the Langmuir model was 814.95 mg/g and 196.06 mg/g for Pb2+ and Cd2+ respectively. Based on mechanism of removing Pb2+ involves reduction, adsorption isotherm did not fit well in experiments data. Time to reach equilibrium was 1 hour and 8 hours for Pb2+ and Cd2+, respectively. Pseudo 2nd order kinetic model explain well kinetics of heavy metal adsorption, thus adsorption is likely to be chemi-sorption. According to the mass transfer mechanism study, 80% of Pb2+ and 60% of Cd2+ were transported rapidly by surface diffusion and residuals are transported by interparticle diffusion. High adsorption capactiy for Pb2+ and Cd2+ would be related with suppression of aggregation, hence NZVI-coffee ground showed the outstanding potential on industrial wastewater treatment facilities with high concentration of heavy metals. 나노영가철은 높은 반응성과 환원력으로 중금속 흡착제로 많은 관심을 받고 있다. 그러나 나노영가철은 강력한 표면에너지와 자성으로 인해 큰 입자로 응집되는 성질이 있고 이는 현장 적용 시 표면적과 반응성을 감소시키는 문제가 있다. 본 연구에서는 나노영가철의 입자 간 응집 문제를 해결하기 위해 나노영가철이 커피찌꺼기에 지지되도록 합성시켰으며 합성한 재료를 이용하여 Pb2+과 Cd2+에 대한 회분식 흡착실험을 진행하였다. pH 6, 20℃ 조건에서 등온흡착실험 결과 Langmuir 모형으로부터 Pb2+과 Cd2+에 대해 각각 814.95 mg/g, 196.06 mg/g의 최대흡착능을 가진 것으로 확인되었다. Pb2+의 경우 환원반응 기작이 작용하여 실험 결과를 등온흡착곡선 모형으로 설명하기 어려운 것으로 나타났다. 반응 평형 시간은 Pb2+에 대해1시간, Cd2+에 대해 8시간이 소요되었다. 유사 2차반응속도 모형이 반응속도를 잘 설명할 수 있는 것으로 나타났기에 흡착형태는 화학적 흡착으로 추정된다. 물질 전달 메커니즘 분석 결과 Pb2+과 Cd2+은 각각 80%와 60%가 표면 확산을 통해 빠른속도로 전달된 이후 나머지는 입자 내부 확산을 통해 전달됨을 확인하였다. 커피찌꺼기로 지지되는 나노영가철은 입자 간응집이 억제되어 높은 중금속 흡착능과 제거율을 가진 것으로 생각되며, 나노영가철-커피찌꺼기는 고농도 중금속 폐액이 발생하는 산업현장에서 적용가능성이 뛰어날 것으로 판단된다.

Nanoscale zero-valent iron for metal/metalloid removal from model hydraulic fracturing wastewater

Sun, Yuqing,Lei, Cheng,Khan, Eakalak,Chen, Season S.,Tsang, Daniel C.W.,Ok, Yong Sik,Lin, Daohui,Feng, Yujie,Li, Xiang-dong Elsevier 2017 CHEMOSPHERE - Vol.176 No.-

<P><B>Abstract</B></P> <P>Nanoscale zero-valent iron (nZVI) was tested for the removal of Cu(II), Zn(II), Cr(VI), and As(V) in model saline wastewaters from hydraulic fracturing. Increasing ionic strength (<I>I</I>) from 0.35 to 4.10 M (Day-1 to Day-90 wastewaters) increased Cu(II) removal (25.4–80.0%), inhibited Zn(II) removal (58.7–42.9%), slightly increased and then reduced Cr(VI) removal (65.7–44.1%), and almost unaffected As(V) removal (66.7–75.1%) by 8-h reaction with nZVI at 1–2 g L<SUP>−1</SUP>. The removal kinetics conformed to pseudo-second-order model, and increasing <I>I</I> decreased the surface area-normalized rate coefficient (<I>k</I> <SUB> <I>sa</I> </SUB>) of Cu(II) and Cr(VI), probably because agglomeration of nZVI in saline wastewaters restricted diffusion of metal(loid)s to active surface sites. Increasing <I>I</I> induced severe Fe dissolution from 0.37 to 0.77% in DIW to 4.87–13.0% in Day-90 wastewater; and Fe dissolution showed a significant positive correlation with Cu(II) removal. With surface stabilization by alginate and polyvinyl alcohol, the performance of entrapped nZVI in Day-90 wastewater was improved for Zn(II) and Cr(VI), and Fe dissolution was restrained (3.20–7.36%). The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in removal trends from Day-1 to Day-90 wastewaters was attributed to: (i) distinctive removal mechanisms of Cu(II) and Cr(VI) (adsorption, (co-)precipitation, and reduction), compared to Zn(II) (adsorption) and As(V) (bidentate inner-sphere complexation); and (ii) changes in solution speciation (e.g., from Zn<SUP>2+</SUP> to ZnCl<SUB>3</SUB> <SUP>−</SUP> and ZnCl<SUB>4</SUB> <SUP>2−</SUP>; from CrO<SUB>4</SUB> <SUP>2−</SUP> to CaCrO<SUB>4</SUB> complex). Bare nZVI was susceptible to variations in wastewater chemistry while entrapped nZVI was more stable and environmentally benign, which could be used to remove metals/metalloids before subsequent treatment for reuse/disposal.</P> <P><B>Highlights</B></P> <P> <UL> <LI> nZVI could remove Cu(II), Zn(II), Cr(VI), and As(V) from fracturing wastewaters. </LI> <LI> High salinity enhanced Fe dissolution and reduced removal rates except Cu(II). </LI> <LI> nZVI entrapment mitigated Fe dissolution and improved metal(loid) removal. </LI> <LI> Removal efficiency varied with interaction mechanisms and solution speciation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

표면개질된 영가철 나노입자를 이용한 질산성 질소 제거율 향상에 대한 연구

임태숙 ( Taesook Lim ),조윤철 ( Yunchul Cho ),조장환 ( Changhwan Cho ),최상일 ( Sangil Choi ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.4

In order to treat groundwater containing high levels of nitrate, nitrate reduction by nano sized zero-valent iron (nZVI) was studied using batch experiments. Compared to nitrate removal efficiencies at different mass ratios of nitrate/Fe0, the removal efficiency at the mass ratio of 0.02% was the highest(54.59%). To enhance nitrate removal efficiency, surface modification of nZVI was performed using metallic catalysis such as Pd, Ni and Cu. Nitrate removal efficiency by Cu-nZVI (at catalyst/Fe0 mass ratio of 0.1%) was 66.34%. It showed that the removal efficiency of Cu-nZVI was greater than that of the other catalysts. The observed rate constant (kobs) of nitrate reduction by Cu-nZVI was estimated to 0.7501 min-1 at the Cu/Fe mass ratio of 0.1%. On the other hand, TEM images showed that the average particle sizes of synthetic nZVI and Cu-nZVI were 40~60 and 80~100 nm, respectively. The results imply that catalyst effects may be more important than particle size effects in the enhancement of nitrate reduction by nZVI.

Aging effects on chemical transformation and metal(loid) removal by entrapped nanoscale zero-valent iron for hydraulic fracturing wastewater treatment

Sun, Yuqing,Lei, Cheng,Khan, Eakalak,Chen, Season S.,Tsang, Daniel C.W.,Ok, Yong Sik,Lin, Daohui,Feng, Yujie,Li, Xiang-dong Elsevier 2018 Science of the Total Environment Vol.615 No.-

<P><B>Abstract</B></P> <P>In this study, alginate and polyvinyl alcohol (PVA)-alginate entrapped nanoscale zero-valent iron (nZVI) was tested for structural evolution, chemical transformation, and metals/metalloids removal (Cu(II), Cr(VI), Zn(II), and As(V)) after 1–2month passivation in model saline wastewaters from hydraulic fracturing. X-ray diffraction analysis confirmed successful prevention of Fe<SUP>0</SUP> corrosion by polymeric entrapment. Increasing ionic strength (<I>I</I>) from 0 to 4.10M (deionized water to Day-90 fracturing wastewater (FWW)) with prolonged aging time induced chemical instability of alginate due to dissociation of carboxyl groups and competition for hydrogen bonding with nZVI, which caused high Na (7.17%) and total organic carbon (24.6%) dissolution from PVA-alginate entrapped nZVI after 2-month immersion in Day-90 FWW. Compared to freshly-made beads, 2-month aging of PVA-alginate entrapped nZVI in Day-90 FWW promoted Cu(II) and Cr(VI) uptake in terms of the highest removal efficiency (84.2% and 70.8%), pseudo-second-order surface area-normalized rate coefficient <I>k</I> <SUB> <I>sa</I> </SUB> (2.09×10<SUP>−1</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP> and 1.84×10<SUP>−1</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP>), and Fe dissolution after 8-h reaction (13.9% and 8.45%). However, the same conditions inhibited Zn(II) and As(V) sequestration in terms of the lowest removal efficiency (31.2% and 39.8%) by PVA-alginate nZVI and <I>k</I> <SUB> <I>sa</I> </SUB> (4.74×10<SUP>−2</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP> and 6.15×10<SUP>−2</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP>) by alginate nZVI. The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in metals/metalloids removal by entrapped nZVI after aging was attributed to distinctive removal mechanisms: (i) enhanced Cu(II) and Cr(VI) removal by nZVI reduction with accelerated electron transfer after pronounced dissolution of non-conductive polymeric immobilization matrix; (ii) suppressed Zn(II) and As(V) removal by nZVI adsorption due to restrained mass transfer after blockage of surface-active micropores. Entrapped nZVI was chemically fragile and should be properly stored and regularly replaced for good performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> nZVI entrapment successfully prevented Fe<SUP>0</SUP> corrosion in fracturing wastewaters. </LI> <LI> Entrapped nZVI was chemically fragile due to dissolution of Na and TOC. </LI> <LI> nZVI passivation promoted Cu(II) and Cr(VI) but inhibited Zn(II) and As(V) removal. </LI> <LI> Effects of nZVI aging on removal efficiency depended on interaction mechanisms. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

고농도 PCE 및 1,1,1 TCA 제거를 위한 영가금속 선정

권수열,김영 한국습지학회 2010 한국습지학회지 Vol.12 No.1

본 연구는 고농도의 PCE 및 1,1,1-TCA가 단독 또는 혼합물로 오염된 지하수 복원을 위해 영가 금속을 이용한 탈염소환원공정을 적용할 때 기술적으로, 경제적으로 가장 적절한 영가금속 선정을 목표로 수행되었다. 고순도 영가철, 고순도 영가아연, 철광석, 고로 슬래그, 차수재용슬래그, 망간 광석 및 아연 광석 등을 대상으로 회분식 반응조 실험을 수행하였으며, PCE, 1,1,1-TCA 및 혼합물의 분해능 및 탈염소화율을 도출하고, 금속 단가 당 변환량을 포함한 경제성 등을 검토하여 최적의 금속광물을 선정하고자 하였다. 연구결과 단일물질 처리시 고순도 영가철과 고순도 영가아연에 의한 제거율 및 분해능이 가장 높게 나타났으며, 그 다음으로 아연광석에 의한 분해능이 양호하였다. 두 물질 제거를 위한 경제성 비교에서는 고순도 영가철과 고순도 영가아연에 비해 아연광석이 매우 양호한 것으로 나타났다. 두 물질의 혼합처리 시에는 단일 처리에 비해 분해능이 감소하는 것으로 나타났다. 이상의 결과로부터 단일 또는 혼합 1,1,1-TCA, PCE 처리를 위한 분해능, 처리특성 및 경제성 등을 고려하였을 때 아연광석이 가장 적절한 금속광물로 사료된다.

0가 금속을 이용한 유해지방족 염소화합물의 제거

장덕진,이승우,이준명,양진우 明知大學校 産業技術硏究所 1998 産業技術硏究所論文集 Vol.17 No.-

Aliphatic chlorinated compounds, majority of which are chlorinated methanes, ethanes, and ethenes, are mainly used as solvents and degreasing agents in industries. Due to long-term usage of these compounds and its concomitant environmental contamination, many of them are frequently detected pollutants in groundwater and soil. U. S. EPA has designated perchloroethylene (PCE), trichloroethylene (TCE), dichloroethylenes, monochloroethylene (vinyl chloride), carbon tetrachloride (CT), and others as top priority pollutants because of their toxicity/carcinogenecity. Extensive efforts are being made to develope technologies to treat chlorinated aliphatics-contaminated environments. Among them, reductive dechlorination reactions by zero-valent metals appear to be very attractive since the reaction mechanism is extremely simple(Fe0+RX+H+→Fe²++RH+X-; X-; chloride ion)and stable, and energy input is not needed at all for these reactions. In this article, significance of environmental contamination by aliphatic chlorinated compounds, treatability of the contamination using zero-valent metals, mechanisms of reductive dechlorination by metals, and application cases were briefly reviewed.

Recovery of precious metals from low-grade automobile shredder residue: A novel approach for the recovery of nanozero-valent copper particles

Singh, J.,Lee, B.K. Pergamon Press ; Elsevier Science Ltd 2016 Waste management Vol.48 No.-

The presence of precious metals (PMs) in low-grade automobile shredder residue (ASR) makes it attractive for recycling. This study investigated the leaching and recovery characteristics of two PMs (Cu and Ag) and two heavy metals (Mn and Co) from ASR. The effects of H<SUB>2</SUB>O<SUB>2</SUB>, leaching temperature, liquid to solid (L/S) ratio, and particle size on metal leaching were determined in an aqueous solution of 0.5M nitric acid. The metal leaching rate was increased with increasing nitric acid concentration, amount of H<SUB>2</SUB>O<SUB>2</SUB>, L/S ratio and temperature. The leaching kinetics was analyzed by using a second-order reaction model. In the analysis of leaching kinetics, the metal leaching data were well fitted (R<SUP>2</SUP>≥0.99) with the second-order reaction model. The activation energy (kJ/mol) for metal leaching was 39.6 for Cu, 17.1 for Ag, 17.3 for Mn and 29.2 for Co. Metal recovery was carried out by fractional precipitation with the addition of advanced Fenton's regent. Metal recovery efficiency was increased to 99.95% for Cu, 99.8% for Mn, 90.0% for Ag and 96.46% for Co with the advanced Fenton's regent. In particular, a novel finding of the PM recovery is that Cu can also be recovered directly from the leachate of ASR in the form of zero-valent copper (ZVC) nanoparticles (NPs). Hydrometallurgical recovery of the metals from ASR using nitric acid is highly efficient.

Enhancing the Bioproduction of 1,3-Propanediol from Glycerol by Integration a Metallic Electron Donation System (MDS) with Zero-Valent Iron

Da Seul KONG,Jung Rae KIM 한국생물공학회 2024 한국생물공학회 학술대회 Vol.2024 No.4

Biochar-supported nZVI (nZVI/BC) for contaminant removal from soil and water: A critical review

Wang, Shengsen,Zhao, Mingyue,Zhou, Min,Li, Yuncong C.,Wang, Jun,Gao, Bin,Sato, Shinjiro,Feng, Ke,Yin, Weiqin,Igalavithana, Avanthi Deshani,Oleszczuk, Patryk,Wang, Xiaozhi,Ok, Yong Sik Elsevier 2019 Journal of hazardous materials Vol.373 No.-

<P><B>Abstract</B></P> <P>The promising characteristics of nanoscale zero-valent iron (nZVI) have not been fully exploited owing to intrinsic limitations. Carbon-enriched biochar (BC) has been widely used to overcome the limitations of nZVI and improve its reaction with environmental pollutants. This work reviews the preparation of nZVI/BC nanocomposites; the effects of BC as a supporting matrix on the nZVI crystallite size, dispersion, and oxidation and electron transfer capacity; and its interaction mechanisms with contaminants. The literature review suggests that the properties and preparation conditions of BC (e.g., pore structure, functional groups, feedstock composition, and pyrogenic temperature) play important roles in the manipulation of nZVI properties. This review discusses the interactions of nZVI/BC composites with heavy metals, nitrates, and organic compounds in soil and water. Overall, BC contributes to the removal of contaminants because it can attenuate contaminants on the surface of nZVI/BC; it also enhances electron transfer from nZVI to target contaminants owing to its good electrical conductivity and improves the crystallite size and dispersion of nZVI. This review is intended to provide insights into methods of optimizing nZVI/BC synthesis and maximizing the efficiency of nZVI in environmental cleanup.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aggregation and passivation of nZVI can be alleviated by surfactants and doping methods. </LI> <LI> BC hinders corrosion and improves the dispersion and electron transfer of nZVI. </LI> <LI> Properties of nZVI depend on those of the BC, feedstock and pyrogenic temperature. </LI> <LI> BC enhances electron transfer from nZVI to the contaminants due to the presence of quinone and graphene moieties. </LI> <LI> nZVI/BC shows strong ability to remove HMs, nitrates, and organic contaminants in soil and water. </LI> </UL> </P>