Liu Zong-Tang, Sun Yu-Feng, Fei Zheng-Hao, Sha Xin-Long, Wen Xiao-Ju, Qian Bin-Bin, Chen Jian, Gu Cheng-Gang
School of Chemical and Environmental Engineering, Yancheng Teachers University, Yancheng 224007, China.
Jiangsu Province Engineering Research Center of Agricultural Breeding Pollution Control and Resource, Yancheng Teachers University, Yancheng 224007, China.
Huan Jing Ke Xue. 2024 Jan 8;45(1):594-605. doi: 10.13227/j.hjkx.202302120.
The pollution control of tetracycline antibiotics in the environment has become a hot topic, and biochar adsorption has become an important technology to remove organic pollutants. Pyrolytic biochars (BC400, BC500, and BC600) were prepared from corn straw and then were modified by KOH to obtain KBC400, KBC500, and KBC600. Among them, KBC400 was selected for secondary pyrolysis activation at 400-600℃ to obtain AKBC400, AKBC500, and AKBC600. The structure characteristics and surface properties of AKBC were also characterized. The adsorption kinetics and thermodynamic characteristics of oxytetracycline hydrochloride (OTC) in the solution by AKBC were investigated using batch experiments. Compared to that of BC400, the specific surface area and pore structure of AKBC were significantly improved, and the aromaticity was also enhanced, resulting in the notable enhancement of the adsorption capacities for OTC. The pseudo-second-order kinetics model could better fit the adsorption process, and AKBC500 had the largest adsorption rate constant and capacity. Both the intraparticle diffusion and film diffusion were the rate-limiting steps. The Langmuir, Freundlich, and Temkin models could fit the adsorption isotherms perfectly. The adsorption of OTC on AKBC was a spontaneous, endothermic, and entropy-increasing process by both physisorption and chemisorption. The pH values in the range of 3.0-7.0 were favorable for the adsorption of OTC by AKBC. The adsorption capacity decreased with the humic acid concentration over 10 mg·L. The adsorption mechanism of OTC by AKBC involved pore filling, hydrogen bonding, π-π conjugation, cation-π bond, and strong electrostatic effect. AKBC still had good reusability for OTC removal after five times of regeneration. The obtained AKBC is a potential adsorbent for OTC removal from water due to the good pore structure, high adsorption capacity, and stable adsorption effect.
环境中四环素类抗生素的污染控制已成为一个热门话题，生物炭吸附已成为去除有机污染物的一项重要技术。以玉米秸秆为原料制备了热解生物炭（BC400、BC500和BC600），然后用KOH对其进行改性，得到KBC400、KBC500和KBC600。其中，选择KBC400在400 - 600℃进行二次热解活化，得到AKBC400、AKBC500和AKBC600。还对AKBC的结构特征和表面性质进行了表征。采用分批实验研究了AKBC对溶液中盐酸土霉素（OTC）的吸附动力学和热力学特性。与BC400相比，AKBC的比表面积和孔结构显著改善，芳香性也增强，导致其对OTC的吸附容量显著提高。准二级动力学模型能更好地拟合吸附过程，AKBC500具有最大的吸附速率常数和吸附容量。颗粒内扩散和膜扩散都是限速步骤。Langmuir、Freundlich和Temkin模型都能很好地拟合吸附等温线。OTC在AKBC上的吸附是一个通过物理吸附和化学吸附的自发、吸热且熵增加的过程。pH值在3.0 - 7.0范围内有利于AKBC对OTC的吸附。腐殖酸浓度超过10 mg·L时，吸附容量降低。AKBC对OTC的吸附机制涉及孔隙填充、氢键、π-π共轭、阳离子-π键和强静电作用。AKBC经过五次再生后对OTC去除仍具有良好的可重复使用性。由于具有良好的孔结构、高吸附容量和稳定的吸附效果，所制备的AKBC是一种从水中去除OTC的潜在吸附剂。
