Jiang Li, Chen Yating, Wang Yifei, Lv Jiayang, Dai Peng, Zhang Jian, Huang Ying, Lv Wenzhou
School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
ACS Omega. 2022 Mar 16;7(12):10502-10515. doi: 10.1021/acsomega.2c00014. eCollection 2022 Mar 29.
Due to its high toxicity, persistence, and bioaccumulation in the food chain, controlling cadmium (Cd) pollution in wastewater is urgent. Activated carbon is a popular material for removing Cd. To improve the Cd(II) adsorption efficiency by increasing the number of oxygen-containing functional groups, -activated carbon (PAAC) was modified with mannitol at a low temperature (150 °C). The textural and chemical characteristics of PAAC and modified PAAC (M-PAAC) were analyzed by surface area analysis, elemental analysis, Boehm's titration, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Batch adsorption experiments were conducted to investigate the influence of Cd(II) concentration, contact time, ionic strength, and pH on Cd(II) adsorption. The main adsorption mechanisms of Cd(II) on activated carbon were quantitatively calculated. The results showed that mannitol modification slightly decreased the (5.30% of PAAC) and increased the content of carboxyl, lactone, and phenolic groups (total increase of 43.96% with PAAC), which enhanced the adsorption capacity of PAAC by 58.59%. The adsorption isotherms of PAAC and M-PAAC were described well using the Temkin model, while the intraparticle diffusion model fitted the Cd(II) adsorption kinetics best. Precipitation with minerals was a crucial factor for Cd(II) adsorption on activated carbon (50.40% for PAAC and 40.41% for M-PAAC). Meanwhile, the Cd(II) adsorption by M-PAAC was also dominated by complexation with oxygen-containing functional groups (33.60%). This research provides a method for recovering wetland plant biomass to prepare activated carbon and efficiently treat Cd-containing wastewater.
由于镉（Cd）具有高毒性、持久性且会在食物链中生物累积，因此控制废水中的镉污染迫在眉睫。活性炭是一种常用的镉去除材料。为了通过增加含氧官能团的数量来提高Cd(II)的吸附效率，在低温（150°C）下用甘露醇对活性炭（PAAC）进行了改性。通过比表面积分析、元素分析、 Boehm滴定、傅里叶变换红外光谱和X射线光电子能谱对PAAC和改性PAAC（M-PAAC）的结构和化学特性进行了分析。进行了批量吸附实验，以研究Cd(II)浓度、接触时间、离子强度和pH对Cd(II)吸附的影响。定量计算了Cd(II)在活性炭上的主要吸附机制。结果表明，甘露醇改性使比表面积略有降低（相对于PAAC降低了5.30%），但增加了羧基、内酯和酚羟基的含量（相对于PAAC总共增加了43.96%），这使得PAAC的吸附容量提高了58.59%。用Temkin模型能很好地描述PAAC和M-PAAC的吸附等温线，而颗粒内扩散模型最能拟合Cd(II)的吸附动力学。与矿物质沉淀是Cd(II)在活性炭上吸附的关键因素（PAAC为50.40%，M-PAAC为40.41%）。同时，M-PAAC对Cd(II)的吸附也主要是通过与含氧官能团络合（33.60%）。本研究提供了一种回收湿地植物生物质制备活性炭并有效处理含镉废水的方法。
