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.
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.
J Environ Manage. 2022 Jan 1;301:113921. doi: 10.1016/j.jenvman.2021.113921. Epub 2021 Oct 11.
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 (NaHCO) 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 NaHCO 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) and As(T) removal ratio (94.0%) at 1.2 V in actual As-contaminated wastewater (1.16 mg L) 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.
生物炭作为一种吸附剂已被广泛应用，其电化学容量和重金属吸附性能可通过氮掺杂得到提高。在这项工作中，采用碳酸氢钠（NaHCO）和尿素分别作为活化剂和氮源，通过煅烧腐植酸钠来合成氮掺杂生物炭（NBC）。然后，将 NBC 用于电化学吸附模拟和实际废水中的 Cd(II)和 As(III,V)。结果表明，NaHCO 活化和氮掺杂可以增加生物炭的表面积和氮含量，有助于提高 Cd(II)和 As(III,V)的吸附性能。随着氮含量的增加，Cd(II)和总砷（As(T)）的电吸附容量先增加后达到平衡，随着煅烧温度的升高，电吸附容量先增加后降低，随着电压的升高而持续增加。在实际含砷废水中（1.16mg/L），在 1.2V 时，Cd(II)的电吸附容量（79.0mg/g）和 As(T)的去除率（94.0%）分别约为其无机吸附容量的 4 倍和 2.6 倍。经过五次循环重复使用后，Cd(II)和 As(T)的去除率仍能保持在初始电吸附容量的 65.8%和 51.7%。这项工作扩展了 NBC 在重金属去除方面的应用。
