Macroporous Carbon Supported Zerovalent Iron for Remediation of Trichloroethylene

Abstract

Groundwater contamination with chlorinated hydrocarbons has become a widespread problem that threatens water quality and human health. Permeable reactive barriers (PRBs), which employ zerovalent iron, are effective for remediation; however, a need exists to reduce the economic and environmental costs associated with constructing PRBs. We present a method to produce zerovalent iron supported on macroporous carbon using only lignin and magnetite. Biochar-ZVI (BC-ZVI) produced by this method exhibits a broad pore size distribution with micrometer sized ZVI phases dispersed throughout a carbon matrix. X-ray diffraction revealed that pyrolysis at 900 °C of a 50/50 lignin–magnetite mixture resulted in almost complete reduction of magnetite to ZVI and that compression molding promotes iron reduction in pyrolysis due to mixing of starting materials. High temperature pyrolysis of lignin yields some graphite in BC-ZVI due to reduction of carbonaceous gases on iron oxides. TCE was removed from water as it passed through a column packed with BC-ZVI at flow rates representative of average and high groundwater flow. One-dimensional convection–dispersion modeling revealed that adsorption by biochar influences TCE transport and that BC-ZVI facilitated removal of TCE from contaminated water by both adsorption and degradation.

Biochar from Pine Wood, Rice Husks and Iron-Eupatorium Shrubs for Remediation Applications: Surface Characterization and Experimental Tests for Trichloroethylene Removal

“…The performance of the BC enriched with Fe was attractive, as more than one removal mechanism may be implicated [ 34 ]. Recent papers have described the reduction of organic contaminants on the ZVI/BC magnetic surface [ 45 , 50 , 51 , 52 ]. In contrast, no intermediates of TCE reduction were revealed in the range of concentration investigated in our study.…”

Impact of Pyrolysis Temperature and Feedstock on Surface Charge and Functional Group Chemistry of Biochars

“…The acid treatment caused development of small carbonyl bands in the CE700 and CE900 spectra. By contrast, the NaOH treatment caused more profound oxidationm as evidenced by the formation of aromatic C‐H stretching bands (Max and Chapados, 2004) (Region C) in spectra of the 700 and 900°C biochars and carbonyl multiplets in Region E. The carbonyl multiplets are a series of weak bands distributed over the functional group region that are caused by Fermi resonance of carbonyls conjugated in large aromatic C systems (Lawrinenko et al, 2017b). Conjugated carbonyls have been previously reported in biochars produced at 700°C and activated C and C blacks produced at high temperatures (Ishizaki and Marti, 1981; Boehm, 1994; Lawrinenko et al, 2016).…”

Synthesis of zero-valent iron/biochar by carbothermal reduction from wood waste and iron mud for removing rhodamine B

“…The above synthesis process needs a large number of reducing reagents, with high raw material cost and complex operation, thus, it can only be applied to laboratory research. Carbothermal reduction is another synthesis method (Lawrinenko et al, 2017;Mandal et al, 2017;Hussain et al, 2017), in which iron compounds and biomass are mixed to pyrolysis at a high temperature, the iron compounds are reduced by the reducing substances generated during biomass pyrolysis, and then Fe 0 /BC is prepared by one step. Lawrinenko et al (2017) successfully prepared Fe 0 /BC through the slow pyrolysis of lignin and magnetite mixtures in a muffle furnace and heated at 900 °C for 4 h. By 79 contrast, carbothermal reduction has the advantages of low raw material cost, simple process, easy scaling, continuous production (Shang et al,207).…”