Removal of nitrate by zero-valent iron and pillared bentonite

Li, Jianfa; Li, Yimin; Meng, Qingling

doi:10.1016/j.jhazmat.2009.09.035

Cited by 95 publications

(29 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Pillared bentonite, prepared by intercalating poly(hydroxo Al(III)) cations into bentonite interlayers, was used together with Fe 0 for removing nitrate in column experiments, where nitrate reduction was significantly increased because of the synergistic effect of bentonite and iron powder [18]. In a continuous flow column (packed with steel wool and seeded with hydrogenotrophic denitrifiers), two simultaneous pathways were proved feasible: one was to use Fe 0 to stoichiometrically reduce nitrate to ammonium, and the other was to use cathodic hydrogen produced during anaerobic Fe 0 corrosion by water to sustain microbial denitrification to reduce nitrate to gaseous products (i.e.…”

Section: Rust Formation and Its Mitigationmentioning

confidence: 99%

A review of nitrate reduction using inorganic materials

Zhu

Getting

2012

Environmental Technology Reviews

100

View full text Add to dashboard Cite

In a biological denitrification system for water and wastewater treatment, an external carbon source (electron donor) is usually needed to generate dedicated microbial communities if intrinsic organic substances are insufficient. Alternative sources of electron donors, especially inorganic donors, are becoming more and more attractive in order to replace or reduce carbon use. In this article, inorganic electron donors, i.e. zero-valent iron, ferrous ion, sulphur and hydrogen are reviewed. While carbon dioxide (greenhouse gas) is produced when organic electron donors are used, inorganic electron donors have the potential advantages to reduce a plant's carbon footprint, and prevent carbon eluting out of the system, as occurs with heterotrophic processes. While sulphur and hydrogen are promising for nitrate removal in terms of reaction kinetics and economical feasibility, zero-valent iron and ferrous ion show potential to be utilized as a supplement to heterotrophic denitrification, where it is anticipated that synergistic effects would occur with autotrophic and heterotrophic denitrification, and thus external carbon consumption can be reduced.

show abstract

Section: Rust Formation and Its Mitigationmentioning

confidence: 99%

A review of nitrate reduction using inorganic materials

Zhu

Getting

2012

Environmental Technology Reviews

100

View full text Add to dashboard Cite

show abstract

“…Indeed, ZVI-based processes work through many mechanisms including adsorption, reduction, and precipitation/immobilization. For this reason, ZVI is an effective material for the removal of a wide range of both inorganic and organic pollutants (chlorinated organic compounds, metals, and metalloids) [4][5][6][7]. In particular, ZVI…”

Section: Introductionmentioning

confidence: 99%

Nanoscopic Zero-Valent Iron Supported on MgO for Lead Removal from Waters

Siciliano

Limonti

2018

Water

View full text Add to dashboard Cite

Lead is one of the most toxic heavy metals that can create a severe risk to water ecosystem health. Zero-valent iron is an effective material for Pb 2+ removal treatments. In particular, nanoscopic zero-valent iron (nZVI) particles are characterized by high reaction rates; nevertheless, their utilization in water and groundwater remediation techniques requires further investigations. Indeed, it is necessary to define effective methods able to avoid the drawbacks due to the aggregation tendency of nanoparticles and their potential uncontrolled transport in groundwater. In this work, nZVI was supported on magnesium oxide grains (MgO_nZVI) to synthesize an alternative material for lead removal from aqueous solutions. Many experiments were conducted under several operating conditions in order to analyze the effectiveness of the produced material in Pb 2+ abatement. The performance of MgO_nZVI was also compared with those detected using commercial microscopic Fe 0 (mZVI) as a reactive material. The experimental findings showed a much greater reactivity of the supported nanoscopic iron particles. By means of a kinetic analysis of batch tests results, it was verified that, both for MgO_nZVI and mZVI, the lead abatement follows a pseudo-second-order kinetic law. The reaction rates were affected by the initial pH of the treatment solution and by the ratio between the Fe 0 amount and initial lead concentration. The efficiency of MgO_nZVI in a continuous test was steadily around 97.5% for about 1000 exchanged pore volumes (PV) of reactive material, while by using mZVI, the lead removal was approximately 88% for about 600 PV. X-ray diffraction (XRD) and energy-dispersive spectroscopy EDS analyses suggested the formation of typical iron corrosion products and the presence of metallic lead Pb 0 and Pb 2+ compounds on exhausted materials.

show abstract

“…Chang et al used chitosan-clay composite materials to immobilize α-amylase, β-glucosidase, and glucoamylase; these immobilized enzymes showed higher activities than free enzymes over broader pH and temperature ranges, and they still kept high residual activity after repeated use for many times [21]. In addition, clay is also very rich in nature, and it has a high adsorption capacity, to enrich substrate compounds at the reaction interface [9,23]. Therefore, clay is an ideal candidate to prepare a composite carrier with chitosan for enzyme immobilization [14,21].…”

Section: Introductionmentioning

confidence: 99%

Improved Catalytic Performance of Lipase Supported on Clay/Chitosan Composite Beads

Shou

Dong

et al. 2017

Catalysts

Self Cite

View full text Add to dashboard Cite

Clay/chitosan composite beads were prepared and used as the carrier to support lipase by adsorption, to improve the activity and stability of lipase in the hydrolysis of olive oil. Under conditions of pH 6.0, 25 • C and adsorption for 10 h, immobilized lipases on chitosan bead (CB-lipase) and three clay/chitosan composite beads, at different clay to chitosan proportions of 1:8 (CCB-8-lipase), 1:5 (CCB-5-lipase) and 1:3 (CCB-3-lipase), were prepared. By comparing the activity of these immobilized lipases, CCB-5-lipase showed the highest activity, followed by CCB-8-lipase > CCB-3-lipase > CB-lipase; this improvement was attributed to the synergetic effect of enrichment of olive oil by clay at the reaction surface and better biocompatibility of chitosan with lipase molecules. The optimum pH and temperature in the reaction respectively changed from 7.0 and 30 • C for free lipase to 7.5 and 35 • C for immobilized forms. Furthermore, the thermal stability and repeated usability of these immobilized lipases were sequenced as CCB-3-lipase > CCB-5-lipase > CCB-8-lipase > CB-lipase, due to greater rigidity of immobilized lipase with the addition of clay, which was further confirmed by SEM. The study shows that the incorporation of clay with chitosan creates a good synergetic effect to improve the catalytic performance of immobilized lipase on clay/chitosan composite.

show abstract

Removal of nitrate by zero-valent iron and pillared bentonite

Cited by 95 publications

References 43 publications

A review of nitrate reduction using inorganic materials

A review of nitrate reduction using inorganic materials

Nanoscopic Zero-Valent Iron Supported on MgO for Lead Removal from Waters

Improved Catalytic Performance of Lipase Supported on Clay/Chitosan Composite Beads

Contact Info

Product

Resources

About