Shang Cen-Yao, Gu Ruo-Ting, Zhang Qiang, Xie Hui-Fang, Wang Bing-Yu
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, Nanjing University of Science and Technology, Nanjing 210094, China.
Huan Jing Ke Xue. 2022 Sep 8;43(9):4888-4901. doi: 10.13227/j.hjkx.202111120.
As one of the large dosages of pharmaceutical and personal care products (PPCPs), acetaminophen is widely present in the water environment and presents potential environmental risks. Therefore, it is necessary to study the removal mechanism of acetaminophen from the environment. Based on the high-value conversion demand of agricultural straw resources in China, straw-derived biochar prepared by pyrolysis has a good application prospect for the sorption and purification of acetaminophen in water. However, the sorption process and mechanism of straw-derived biochar for acetaminophen remain unclear. Four types of straw (rice, wheat, maize, and bean straw) were chosen as raw materials, and straw-derived biochars were prepared through the pyrolysis method at 400℃ and 500℃. The batch sorption experiments were used to study the sorption of acetaminophen to different sources and different pyrolysis temperature biochars. The effect of humic acid and pH on the sorption process was also studied. The results showed that:based on the Freundlich and site energy distribution models, the sorption of acetaminophen on biochar at 500℃ biochar was significantly higher than that at 400℃ biochar (the sorption coefficient was 1.16-2.53 times higher), and 500℃ biochar had more high-energy sorption sites. For high-temperature pyrolysis biochar, the primary sorption mechanism was pore sorption and π-π effect; for low-temperature pyrolysis biochar, the primary sorption mechanism for removing acetaminophen was H-bonding. The presence of humic acid enhanced the sorption of acetaminophen, which was attributed to the strong interaction between the humic acid selected in the experiment and acetaminophen, thus promoting adsorption. The decrease in sorption capacity of biochar caused by the increasing pH was mainly attributed to the pore blockage resulting from the aggregation of acetaminophen molecules. The pore sorption and π-π interaction of acetaminophen on straw-derived biochar could be promoted by increasing pyrolysis temperature. These experiments on humic acid and pH show that straw-derived biochar is not affected by humic acid and has good sorption performance in a low pH environment.
作为大剂量的药物和个人护理产品（PPCPs）之一，对乙酰氨基酚广泛存在于水环境中并呈现潜在的环境风险。因此，有必要研究对乙酰氨基酚在环境中的去除机制。基于我国农业秸秆资源的高值化转化需求，通过热解制备的秸秆基生物炭在水中对乙酰氨基酚的吸附和净化方面具有良好的应用前景。然而，秸秆基生物炭对乙酰氨基酚的吸附过程和机制仍不清楚。选择四种秸秆（稻草、小麦秸秆、玉米秸秆和豆秸）作为原料，并通过在400℃和500℃下的热解方法制备秸秆基生物炭。采用批次吸附实验研究对乙酰氨基酚对不同来源和不同热解温度生物炭的吸附。还研究了腐殖酸和pH对吸附过程的影响。结果表明：基于Freundlich模型和位点能量分布模型，对乙酰氨基酚在500℃生物炭上的吸附显著高于400℃生物炭（吸附系数高1.16 - 2.53倍），且500℃生物炭具有更多的高能吸附位点。对于高温热解生物炭，主要吸附机制是孔隙吸附和π-π效应；对于低温热解生物炭，去除对乙酰氨基酚的主要吸附机制是氢键作用。腐殖酸的存在增强了对乙酰氨基酚的吸附，这归因于实验中所选腐殖酸与对乙酰氨基酚之间的强相互作用，从而促进了吸附。pH升高导致生物炭吸附容量降低主要归因于对乙酰氨基酚分子聚集导致的孔隙堵塞。提高热解温度可促进对乙酰氨基酚在秸秆基生物炭上的孔隙吸附和π-π相互作用。这些关于腐殖酸和pH的实验表明，秸秆基生物炭不受腐殖酸影响，在低pH环境中具有良好的吸附性能。
