Electrosorption of cadmium and arsenic from wastewaters using nitrogen-doped biochar: Mechanism and application

Shiwei Lin; Xiong Yang; Lihu Liu; Anyu Li; Guohong Qiu

doi:10.1016/j.jenvman.2021.113921

Electrosorption of cadmium and arsenic from wastewaters using nitrogen-doped biochar: Mechanism and application

J Environ Manage. 2022 Jan 1:301:113921. doi: 10.1016/j.jenvman.2021.113921. Epub 2021 Oct 11.

Authors

Shiwei Lin¹, Xiong Yang¹, Lihu Liu¹, Anyu Li¹, Guohong Qiu²

Affiliations

¹ Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, Hubei Key Laboratory of Soil Environment and Pollution Remediation, State Environmental Protection Key Laboratory of Soil Health and Green Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China.
² Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, Hubei Key Laboratory of Soil Environment and Pollution Remediation, State Environmental Protection Key Laboratory of Soil Health and Green Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China. Electronic address: qiugh@mail.hzau.edu.cn.

PMID: 34731946
DOI: 10.1016/j.jenvman.2021.113921

Abstract

Biochar has been widely applied as an adsorbent, whose electrochemical capacity and heavy metal adsorption performance can be improved by nitrogen doping. In this work, nitrogen-doped biochar (NBC) was synthesized by calcinating sodium humate with sodium bicarbonate (NaHCO₃) and urea as the activation agent and nitrogen source, respectively. The NBC was then used to electrochemically adsorb Cd(II) and As(III,V) from simulated and actual wastewaters, respectively. The results indicated that NaHCO₃ activation and nitrogen doping could increase the surface area and nitrogen content of the biochar, contributing to the enhancement of adsorption performance for Cd(II) and As(III,V). The electrosorption capacities for Cd(II) and total arsenic (As(T)) increased first and then reached equilibrium with increasing nitrogen content, increased first and then decreased with increasing calcination temperature, and consistently increased with increasing voltage. The Cd(II) electrosorption capacity (79.0 mg g^-1) and As(T) removal ratio (94.0%) at 1.2 V in actual As-contaminated wastewater (1.16 mg L^-1) were about 4 and 2.6 folds of their inorganic adsorption capacities, respectively. After five cycles of reuse, the Cd(II) and As(T) removal ratio could be maintained at 65.8% and 51.7% of the initial electrosorption capacity. This work expands the application of NBC for heavy metal removal.

Keywords: Arsenic; Biochar; Cadmium; Electrosorption; Nitrogen doping.

MeSH terms

Adsorption
Arsenic*
Cadmium
Charcoal
Nitrogen
Wastewater
Water Pollutants, Chemical*

Substances

Waste Water
Water Pollutants, Chemical
biochar
Cadmium
Charcoal
Arsenic
Nitrogen