Citation: Xianxin Luo, Jianhao Xu, Qi Luo, Yan Xiao, Feng Wei, Meitong Li, Wenjiao Yuan, Penghui Shao, Shenglian Luo. Efficient copper sorption from saline wastewater using citrate-modified biochar with robust anti-salt interferences[J]. Chinese Chemical Letters, ;2026, 37(5): 111914. doi: 10.1016/j.cclet.2025.111914 shu

Efficient copper sorption from saline wastewater using citrate-modified biochar with robust anti-salt interferences

Xianxin Luo ^{a, b} ,
Jianhao Xu ^b ,
Qi Luo ^b ,
Yan Xiao ^b ,
Feng Wei ^c ,
Meitong Li ^d ,
Wenjiao Yuan ^d ,
Penghui Shao ^{b, *,} ,
Shenglian Luo ^{a, b, *,}

a.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
b.
College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063, China
c.
Jiangxi Hongcheng Environment Co., Ltd., Nanchang 330038, China
d.
School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China

penghui_shao@163.com

sllou@hnu.edu.cn

Received Date: 1 April 2025
Revised Date: 12 August 2025
Accepted Date: 28 September 2025
Available Online: 28 September 2025

Figures(4)

Eliminating heavy metals from industrial high-salinity wastewater is imperative for sustainable industrial development and environmental protection. Herein, a citrate-modified biochar that demonstrated robust anti-salt interference was developed. The sorbent achieved an adsorption capacity of 252.14 mg/g in 4.1 mol/L NaCl solution and 232.55 mg/g in 1.4 mol/L Na₂SO₄ solution, maintaining efficient Cu(Ⅱ) adsorption over four cycles. It retained an adsorption capacity of 236.89 mg/g in real waste salt-derived brine. Adsorption followed pseudo-first-order kinetics (k = 0.0901 min^-1) and conformed to the Langmuir isotherm (q_max = 251.21 mg/g) model, indicating that physical adsorption on a homogeneous surface primarily governs the adsorption mechanisms. Thermodynamic analysis revealed that the adsorption is spontaneous and endothermic, with enhanced affinity for Cu(Ⅱ) at higher temperatures. Oxygen-containing groups, especially the hydroxyl group, drove adsorption via surface precipitation/complexation, ultimately generating posnjakite (Cu₄(SO₄)(OH)₆·2H₂O). Cost analysis showed that the total expenditure for treating 1000 L of wastewater (300 mg_Cu/L) was ＄28.89 (＄0.0963/g_Cu(Ⅱ)) and the treatment capacity using fixed-bed columns was 120 L/kg. These findings offer a viable and cost-effective strategy for Cu(Ⅱ) elimination from high-salinity wastewater.
- Biochar,
- Copper,
- Adsorption,
- Citrate modification,
- High-salinity wastewater
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