Mechanochemical synthesis of microscale zero-valent iron/N-doped graphene-like biochar composite for degradation of tetracycline via molecular O activation.

In this study, we prepared a micron zero-valent iron/N-doped graphene-like biochar (mZVI/NGB) composite using a mechanochemical method for tetracycline (TC) degradation through O activation. The mZVI and NGB components formed a strong coupling catalytic system, with mZVI acting as an electron pool and NGB as a catalyst for HO generation. Under circumneutral pH (5.

Tannic acid modified microscale zero valent iron (TA-mZVI) with enhanced anti-passivation capability for Cr(VI) removal.

The removal of Cr(VI) from aqueous solutions using microscale zerovalent iron (mZVI) shows promising potential. However, the surface passivation of mZVI particles hinders its widespread application. In this study, we prepared tannic acid (TA) modified mZVI composite (TA-mZVI) by a simple sonication method.

Sulfidated microscale zero-valent iron/reduced graphene oxide composite (S-mZVI/rGO) for enhanced degradation of trichloroethylene: The role of hydrogen spillover.

Atomic hydrogen (H*) has long been thought to play an important role in the dechlorination of trichloroethylene (TCE) by carbon-supported zero-valent iron (ZVI), which offers an alternative pathway for TCE dechlorination. Herein, we demonstrate that the reductive dechlorination of TCE by sulfidated microscale ZVI (S-mZVI) can be further enhanced by promoting the formation of H* through the introduction of reduced graphene oxide (rGO). The completely degradation of 10 mg/L TCE can be achieved by S-mZVI/rGO within 24 h, which was 3.

Biological effects of tourmaline treatment on spp. during the reductive dechlorination of trichloroethylene.

In the present study, to develop the application of biostimulation for the remediation of trichloroethylene (TCE) in contaminated groundwater/soil, a mixed culture containing spp. was employed to investigate the biological effects of the polarized mineral tourmaline on the dechlorination performance, community structure, cell proliferation and expression of two model gene ( and ) coding for reductive dehalogenases (Rdase). It was observed that tourmaline could speed up the biological dechlorination of TCE by promoting the growth and metabolism of the bacteria, impacting the expression of RDase genes.

Quantification of 2-chlorohydroquinone based on interaction between N-doped carbon quantum dots probe and photolysis products in fluorescence system.

As a member of chlorophenolic compounds, 2-chlorohydroquinone (HQCl) has been widely used as intermediates in various chemical industries and leaded to serious threat on the environment. It is urgent to develop simple and robust analytical method for sensitive and selective determination of HQCl. Carbon quantum dots (CQDs), a promising photoluminescence nanomaterial, have gained sufficient concern as optical sensors owing to their outstanding photochemical properties.

Strong influence of degree of substitution on carboxymethyl cellulose stabilized sulfidated nanoscale zero-valent iron.

Carboxymethyl cellulose (CMC) has been widely adopted as stabilizer to enhance the subsurface mobility of nanoscale zerovalent iron (nZVI). However, CMC surface modification also cause severe decrease of the longevity and electron utilization efficiency (ε) of nZVI, which is still not well understood. In this study, we demonstrate the negative influence of CMC on the properties of sulfidated nZVI (S-nZVI) could be reversed by increasing the degree of substitution (D.

NiP nanocrystals embedded Ni-MOF nanosheets supported on nickel foam as bifunctional electrocatalyst for urea electrolysis.

It's highly desired but challenging to synthesize self-supporting nanohybrid made of conductive nanoparticles with metal organic framework (MOF) materials for the application in the electrochemical field. In this work, we report the preparation of NiP embedded Ni-MOF nanosheets supported on nickel foam through partial phosphidation (NiP@Ni-MOF/NF). The self-supporting NiP@Ni-MOF/NF was directly tested as electrode for urea electrolysis.

Preparation of palladized carbon nanotubes encapsulated iron composites: highly efficient dechlorination for trichloroethylene and low corrosion of nanoiron.

A method developed based on the capillary effect and capillary condensation theory was used to synthesize an innovative Fe/C/Pd composite in this study. This composite (Fe@CNTs@Pd) consists of carbon nanotubes (CNTs) with nanoscale zerovalent iron (NZVI) on the inner surface and palladium nanoparticles supported on the outer surface of CNTs. This structure successfully addresses the problems of high iron corrosion rate and lower utilization rate of hydrogen in the application of bimetal nanoparticles for trichloroethylene (TCE) removal.

Dechlorinating performance of Dehalococcoides spp. mixed culture enhanced by tourmaline.

Dehalococcoides spp. were extensively studied and applied to in-situ trichloroethylene (TCE) remediation since it is the only genus that can reduce TCE to harmless ethene completely. However, this technology was hindered because of the requirement of electron donor (i.

Simultaneous Adsorption and Degradation of Cr(VI) and Cd(II) Ions from Aqueous Solution by Silica-Coated Fe (0) Nanoparticles.

Core-shell silica-coated Fe(0) nanoparticles (Fe@SiO2) were prepared in one-step synthesis by aqueous reduction combined with modified Stöber method. The as-prepared Fe@SiO2 were then used for simultaneous removal of Cr(VI) and Cd(II) from aqueous solution. Batch tests indicated that Fe@SiO2 exhibited high removal capacity toward Cr(VI) and Cd(II).

Reduction of nitrate by bimetallic Fe/Ni nanoparticles.

Bimetallic Fe/Ni nanoparticles were synthesized and their nitrate reduction capacity was studied. Nitrate (354 mg L(-1), equal to 5.71 mmol L(-1)) reduction was performed using Fe/Ni nanoparticles with various Ni contents (1.

One-step synthesis and characterization of core-shell Fe@SiO2 nanocomposite for Cr (VI) reduction.

A facile one-step method was developed to fabricate mono-dispersed Fe nanoparticles (Fe NPs) coated with SiO(2) shell by aqueous reduction method combined with modified Stöber method. Borohydride was acted not only as a reductant for iron salt but also as a catalyst for hydrolysis and polycondensation reaction of tetraethylorthosilicate (TEOS), and more importantly, there was no need to use surface primer for the generation of Fe NPs and catalyst NH(4)OH for SiO(2). Both the Fe NPs agglomeration and SiO(2) shell thickness can be controlled through the synthetic conditions.

Stabilization of Fe(0) nanoparticles with silica fume for enhanced transport and remediation of hexavalent chromium in water and soil.

Effective in situ remediation of Cr(VI) in groundwater requires the successful delivery of reactive iron particles to the subsurface. Fe(0) nanoparticles (20-110 nm diameter) supported on silica fume were synthesized by borohydride reduction of an aqueous iron salt in the presence of a support material. The experimental result showed that attachment of Fe(0) nanoparticles on the commercial available sub-micrometer silica fume prevented them from aggregation while maintaining the particle reactivity.

Removal of hexavalent chromium in soil and groundwater by supported nano zero-valent iron on silica fume.

Silica fume supported-Fe(0) nanoparticles (SF-Fe(0)) were prepared using commercial silica fume as a support. The feasibility of using this SF-Fe(0) for reductive immobilization of Cr(VI) was investigated through batch tests. Compared with unsupported Fe(0), SF-Fe(0) was significantly more active in Cr(VI) removal especially in 84 wt% silica fume loading.

Reductive dechlorination of activated carbon-adsorbed trichloroethylene by zero-valent iron: carbon as electron shuttle.

Sequestration of organic contaminants in carbonaceous materials can significantly affect contaminant fate and transport. We investigated the reductive dechlorination of granular-activated carbon (GAC)-adsorbed trichloroethylene (TCE) by nanoscale zero-valent iron (nZVI) to understand the effect of sequestration on abiotic reactivity of organic contaminants. Significant reduction of TCE sequestered in GAC micropores was observed, even though direct contact with nZVI was unlikely.

Reduction and immobilization of chromium(VI) by nano-scale Fe0 particles supported on reproducible PAA/PVDF membrane.

A new class of nano-scale Fe0 particles (NZVI) supported on a PAA/PVDF membrane (NZVI-PAA/PVDF) were synthesized and the feasibility of using NZVI-PAA/PVDF for reductive immobilization of Cr(VI) in water was investigated through laboratory batch tests. The results showed that the Cr(VI) removal capacity of NZVI-PAA/PVDF was 181 mg Cr/g Fe at an initial Cr(VI) concentration of 20 mg L(-1) under pH 6.5 +/- 0.

Effect of bimetallic and polymer-coated Fe nanoparticles on biological denitrification.

Bimetallic nanoparticles (nano Fe-Ni, nano Fe-Cu) and coated iron nanoparticles (chitosan-Fe(0), sodium oleate-Fe(0)) were utilized to support autotrophic denitrification. In comparison to nanoscale zero-valent iron (NZVI) particles, Ni-containing nanoparticles resulted in faster nitrate removal, but generated 17% more ammonium. The nano Fe-Cu integrated system, required two days less than the unmodified NZVI integrated system to remove all the nitrate and decrease ammonium by 13%, but a large amount of nitrite remained in the system.

Effects of nano-scale zero-valent iron particles on a mixed culture dechlorinating trichloroethylene.

Nano-scale zero-valent iron particles (NZVI) are increasingly being used to treat sites contaminated with chlorinated solvents. This study investigated the effect of NZVI on dechlorinating microorganisms that participate in the anaerobic bioremediation of such sites. NZVI can have a biostimulatory effect associated with water-derived cathodic H(2) production during its anaerobic corrosion (730+/-30 micromol H(2) was produced in 166 h in abiotic controls with 1 g/L NZVI) or an inhibitory effect upon contact with cell surfaces (assessed by transmission electron microscopy).

Reactivity characteristics of poly(methyl methacrylate) coated nanoscale iron particles for trichloroethylene remediation.

The unstable characteristic of nanoscale zerovalent iron (NZVI) has been a drawback in practical application, despite the expectation of an enhanced reactivity. It has been ever-increasing interests to maintain the NZVI stability in air without significant reactivity sacrifice. This study demonstrated a novel method of coating NZVI particles with poly(methyl methacrylate) (PMMA), which protected the core iron nanoparticles from oxidation in air and enhanced their dispersion stability in organic solvents.

Decreasing ammonium generation using hydrogenotrophic bacteria in the process of nitrate reduction by nanoscale zero-valent iron.

An integrated nitrate treatment using nanoscale zero-valent iron (NZVI) and Alcaligenes eutrophus, which is a kind of hydrogenotrophic denitrifying bacteria, was conducted to remove nitrate and decrease ammonium generation. Within 8 days, nitrate was removed completely in the reactors containing NZVI particles plus bacteria while the proportion of ammonium generated was only 33%. That is a lower reduction rate but a smaller proportion of ammonium relative to that in abiotic reactors.

[Microbial reductive dechlorination of TCE with nano iron serving as electron donor].

A trichloroethylene (TCE) dechlorinating enrichment (Dehalococcoides spp.), which was isolated from soil of chlorinated ethene contaminated site, was used to investigate whether nano-scale zero valent iron (NZVI) could serve as electron donor for this consortium via cathodic H2 production during anaerobic corrosion. The results show that in the presence of methanol serving as electron donor, dechlorinating culture of 25 fold dilution [(2.

Preparation of chitosan-stabilized Fe(0) nanoparticles for removal of hexavalent chromium in water.

Chitosan-stabilized Fe(0) nanoparticles (CTO-Fe(0)) and Fe(0) nanoparticles synthesized in ethanol-water mixed system (EW-Fe(0)) were tested for reduction of Cr(VI) in water. Fourier transform infrared (FTIR) study suggested that nitrogen and oxygen atoms are the binding sites for chitosan on iron which was accountable for the stability of Fe(0) nanoparticles. While the EW-Fe(0) ignites spontaneously when exposed to air, the CTO-Fe(0) was still in zero valence state after exposure to air over 2-month period as shown by X-ray powder diffraction patterns.

[Preparation of coated iron nanoparticles for reduction of trichloroethylene].

Nanoscale alpha-Fe particles with size of about 80 nm were prepared with a microemulsion-coated method. The results demonstrated that this kind of iron particles could exist stably in the air for 7 d compared with nanoscale iron particles prepared by liquid-phase and microemulsion methods. The removal rate of trichloroethylene with an initial concentration of 10 mg x L(-1) can reach 90% in 700 h.

Kinetics of hexavalent chromium removal from water by chitosan-Fe0 nanoparticles.

Chitosan-Fe(0) nanoparticles (chitosan-Fe(0)) were prepared using nontoxic and biodegradable chitosan as a stabilizer. Batch experiments were conducted to evaluate the influences of initial Cr(VI) concentration and other factors on Cr(VI) reduction on the surface of the chitosan-Fe(0). The overall disappearance of Cr(VI) may include both physical adsorption of Cr(VI) onto the chitosan-Fe(0) surface and subsequent reduction of Cr(VI) to Cr(III).

Preparation of spherical iron nanoclusters in ethanol-water solution for nitrate removal.

In this study, a higher surface area spherical nanoscale zero valent iron (HNZVI) cluster (80 nm, 54.25 m(2)g(-1)) was synthesized in ethanol-water mixed solvent in the presence of dispersion agent of polyglycol (PEG). At the same time, a lower surface area nanoscale zero valent iron (LNZVI) particle (80 nm, 8.