Synergistic effect and mechanism of Cd(II) and As(III) adsorption by biochar supported sulfide nanoscale zero-valent iron

Xiaoyu Zheng; Qiuju Wu; Chao Huang; Ping Wang; Hao Cheng; Chengyou Sun; Jian Zhu; Haiyin Xu; Ke Ouyang; Jing Guo; Zhiming Liu

doi:10.1016/j.envres.2023.116080

Synergistic effect and mechanism of Cd(II) and As(III) adsorption by biochar supported sulfide nanoscale zero-valent iron

Environ Res. 2023 Aug 15;231(Pt 1):116080. doi: 10.1016/j.envres.2023.116080. Epub 2023 May 8.

Authors

Xiaoyu Zheng¹, Qiuju Wu¹, Chao Huang², Ping Wang³, Hao Cheng¹, Chengyou Sun¹, Jian Zhu¹, Haiyin Xu¹, Ke Ouyang¹, Jing Guo⁴, Zhiming Liu⁵

Affiliations

¹ College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China.
² College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China. Electronic address: huangchao@csuft.edu.cn.
³ College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China. Electronic address: pingwang@csuft.edu.cn.
⁴ College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, Hunan, China.
⁵ Department of Biology, Eastern New Mexico University, Portales, NM, 88130, USA. Electronic address: zhiming.liu@enmu.edu.

PMID: 37164285
DOI: 10.1016/j.envres.2023.116080

Abstract

Biochar derived from bamboo was used to support sulfide nanoscale zero-valent iron (S-nZVI@BC) for simultaneous removal of Cd(II) and As (III) from aqueous media. Scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD) characterization confirmed the successful synthesis of the S-nZVI@BC. Adsorption kinetics and isotherms indicated that co-adsorption of Cd(II) and As(III) onto S-nZVI@BC was well represented by pseudo-second-order model (R²_Cd(II) = 0.990, R²_As(III) = 0.995) and Langmuir model (R²_Cd(II) = 0.954, R²_As(III) = 0.936). The maximum adsorption was 162.365 and 276.133 mg/g for Cd(II) and As(III), respectively, in a co-adsorption system, which was significantly higher than that in a single adsorption system (103.195 and 223.736 mg/g, respectively). Batch experiments showed that the Cd(II)-to-As(III) concentration ratio significantly affected the co-adsorption with the optimal ratio of 1:2. Ca²⁺ and Mg²⁺ significantly inhibited Cd(II) removal. In contrast, phosphate and humic acid significantly inhibited As(III) removal. Electrochemical analysis indicated S-nZVI@BC had a lower corrosion potential and resistance than nZVI@BC, making it more conducive to electron transfer and chemical reaction. Electrostatic adsorption, complexation, co-precipitation, and redox were the primary mechanisms for Cd(II) and As(III) removal. Overall, the present study provides new insights into the synergistic removal of Cd(II) and As(III) by S-nZVI@BC, which is a very promising adsorbent for the effective removal of Cd(II) and As(III) from contaminated wastewater.

Keywords: Arsenic; Biochar; Cadmium; S-nZVI@BC; Synergistic effect.

MeSH terms

Adsorption
Cadmium / analysis
Iron* / chemistry
Water Pollutants, Chemical* / analysis

Substances

Iron
biochar
Cadmium
Water Pollutants, Chemical