Efficient Hexavalent Chromium Removal by Nano-Cerium Oxide Functionalized Biochar:Insight the Role of Reduction

26 Pages Posted: 4 Feb 2023

See all articles by Kun Luo

Kun Luo

Changsha University

Nengfa Lin

affiliation not provided to SSRN

Xue Li

Changsha University

Ya Pang

Changsha University

Liping Wang

Changsha University

Min Lei

Changsha University

Qi Yang

Hunan University

Abstract

The strong toxicity of hexavalent chromium (Cr(VI)) have spurred great interests in developing effective technologies to remove it from environment. In this study, a cost-effective and recyclable adsorbent nano-cerium (Ce) oxide functionalized peanut shell biochar (BC-Ce) was synthetized by impregnation-precipitation-pyrolysis process and employed in simultaneous adsorption and reduction of Cr(VI) in water. Compared with the original biochar, the as-prepared composite material exhibited better Cr(VI) adsorption ability. Its maximum Cr(Ⅵ) adsorption capacity calculated by Langmuir achieved 47.83 mg·g-1, which was much greater than that of original biochar (9.24 mg·g-1). The BC-based materials displayed obvious reduction behavior for Cr(Ⅵ) and partially adsorbed Cr(VI) was reduced to less toxic Cr(III). When 4 g·L-1 BC-based materials were used to treat 50 mg·L-1 Cr(VI) solution, the Cr(Ⅲ)t/Cr(Ⅵ)0 for BC-Ce reached to 18.10% after adsorption, meanwhile that for BC was only 3.66%. Characterization results indicated that the better Cr(VI) reduction induced by BC-Ce was mainly attributed to the comprehensive effect of oxygen-containing functional group (OFGs), carbon-centered persistent free radicals (PFRs), oxygen vacancies and graphitic structure in BC-Ce. The CeO2 supported on the surface of BC facilitated the generation of more OFGs (phenolic-OH and C-O), PFRs and oxygen vacancies, thus provided abundant sites for chemical reduction of Cr(VI). Moreover, the graphitic structure in BC-Ce promoted the transfer of electrons from graphite carbon to Cr(VI). This study provided a new insight into the mechanisms of Cr(VI) removal from water by BC-Ce, namely, except for adsorption, the reduction behavior should not be overlooked in Cr(Ⅵ) removal by BC-based materials.

Keywords: Biochar, Cerium oxide, Cr(VI), oxygen-containing functional group (OFGs), persistent free radicals (PFRs)

Suggested Citation

Luo, Kun and Lin, Nengfa and Li, Xue and Pang, Ya and Wang, Liping and Lei, Min and Yang, Qi, Efficient Hexavalent Chromium Removal by Nano-Cerium Oxide Functionalized Biochar:Insight the Role of Reduction. Available at SSRN: https://ssrn.com/abstract=4348239 or http://dx.doi.org/10.2139/ssrn.4348239

Kun Luo

Changsha University ( email )

Changsha
China

Nengfa Lin

affiliation not provided to SSRN ( email )

No Address Available

Xue Li

Changsha University ( email )

Changsha
China

Ya Pang

Changsha University ( email )

Changsha
China

Liping Wang

Changsha University ( email )

Changsha
China

Min Lei

Changsha University ( email )

Changsha
China

Qi Yang (Contact Author)

Hunan University ( email )

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