College of Environment and Ecology, Hunan Agricultural University, Changsha, China.
Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, Changsha, China.
Water Environ Res. 2024 Sep;96(9):e11117. doi: 10.1002/wer.11117.
Water pollution involves the coexistence of microplastics (MPs) and traditional pollutants, and how can MPs influence the adsorption of other pollutants by biochar during the treatment process remains unclear. This study aimed to investigate the influence of polystyrene microplastics (PS MPs) on the adsorption of cadmium (Cd) and ciprofloxacin (CIP) by magnetic biochar (MTBC) in the single and binary systems. MTBC was prepared using tea leaf litter; the effects of time, pH, and salt ions on the adsorption behaviors were investigated; and X-ray photoelectronic spectroscopy (XPS) and density flooding theory analysis were conducted to elucidate the influence mechanisms. Results indicated that PS MPs reduced the pollutants adsorption by MTBC due to the heterogeneous aggregation between PS MPs and MTBC and the surface charge change of MTBC induced by PS MPs. The effects of PS MPs on heavy metals and antibiotics adsorption were distinctly different. PS MPs reduced Cd adsorption on MTBC, which were significantly influenced by the solution pH and salt ions contents, suggesting the participation of electrostatic interaction and ion exchange in the adsorption, whereas the effects of PS MPs on CIP adsorption were inconspicuous. In the hybrid system, PS MPs reduced pollutants adsorption by MTBC with 66.3% decrease for Cd and 12.8% decrease for CIP, and the more remarkable reduction for Cd was due to the predominated physical adsorption, and CIP adsorption was mainly a stable chemisorption. The influence of PS MPs could be resulted from the interaction between PS MPs and MTBC with changing the functional groups and electrostatic potential of MTBC. This study demonstrated that when using biochar to decontaminate wastewater, it is imperative to consider the antagonistic action of MPs, especially for heavy metal removal. PRACTITIONER POINTS: Magnetic biochar (MTBC) was prepared successfully using tea leaf litter. MTBC could be used for cadmium (Cd) and ciprofloxacin (CIP) removal. Polystyrene microplastics (Ps MPs) reduced Cd/CIP adsorption by MTBC. Ps MPs effects on Cd adsorption were more obvious than that of CIP. Ps MPs changed the functional groups and electrostatic potential of MTBC, thus influencing MTBC adsorption.
水污染涉及微塑料 (MPs) 和传统污染物的共存，而 MPs 在处理过程中如何影响生物炭对其他污染物的吸附仍不清楚。本研究旨在研究聚苯乙烯微塑料 (PS MPs) 对单双系统中磁性生物炭 (MTBC) 对镉 (Cd) 和环丙沙星 (CIP) 的吸附的影响。MTBC 是用茶叶残渣制备的；研究了时间、pH 值和盐离子对吸附行为的影响；并进行了 X 射线光电子能谱 (XPS) 和密度淹没理论分析，以阐明影响机制。结果表明，PS MPs 由于 PS MPs 和 MTBC 之间的异质聚集以及 PS MPs 引起的 MTBC 表面电荷变化，减少了 MTBC 对污染物的吸附。PS MPs 对重金属和抗生素吸附的影响明显不同。PS MPs 降低了 MTBC 对 Cd 的吸附，这明显受溶液 pH 值和盐离子含量的影响，表明静电相互作用和离子交换在吸附过程中起作用，而 PS MPs 对 CIP 吸附的影响不明显。在混合体系中，PS MPs 减少了 MTBC 对污染物的吸附，Cd 的吸附减少了 66.3%，CIP 的吸附减少了 12.8%，Cd 的吸附减少更为明显，这是由于主要是物理吸附，而 CIP 的吸附主要是稳定的化学吸附。PS MPs 的影响可能是由于 PS MPs 和 MTBC 之间的相互作用，改变了 MTBC 的官能团和静电势。本研究表明，当使用生物炭处理废水时，必须考虑 MPs 的拮抗作用，特别是对于重金属的去除。
