Qilu University of Technology (Shandong Academy of Sciences), Shandong Analysis and Test Center, Jinan 250014, China.
Shandong Jinan Eco-Environmental Monitoring Center, Jinan 250014, China.
Sci Total Environ. 2022 Mar 20;813:152488. doi: 10.1016/j.scitotenv.2021.152488. Epub 2021 Dec 25.
Coconut shell activated carbon (Csac) is one of the most widely used materials to remove cadmium (Cd) from contaminated water. A large diversity of microorganisms exists in various aquatic systems and may aid Cd removal by Csac. In this study, we explored the reactions of Csac with microalgae (Chlorella) in Cd-containing media. The results of scanning electron microscope (SEM) imaging, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), superconducting pulse-Fourier transform nuclear magnetic resonance (pulse-FT NMR) and X-ray photoelectron spectroscopy (XPS) indicated that Chlorella could adhere in the micropores of Csac formed Csac@Chlorella composite adsorbent loading Chlorella. Furthermore, the composite adsorbent surface had abundant functional groups such -COOH, -OH and C-O-C, which served as active sites during the adsorption process. Compared with Csac, Csac@Chlorella had an enhanced Cd adsorption capacity evidently. The results showed that pH 8, 0.2 g Csac, OD of 0.1 for Chlorella were optimal conditions for maximum Cd adsorption capacity within one hour contact time. Furthermore, the Cd adsorption process was well described by the pseudo-second-order and Langmuir adsorption isotherm models. The models revealed that the adsorption process was mainly based on chemical adsorption of a single molecular layer, accompanied by electrostatic attraction, complexation and intracellular adsorption, amongst other parameters. Collectively, the findings illustrate that the microalgae (Chlorella)-Csac-Cd interaction is complex and will thus have immense interest to a broad range of biological, environmental, and geoscience communities.
椰壳活性炭（Csac）是去除受污染水中镉（Cd）最常用的材料之一。各种水生系统中存在着大量的微生物，它们可能通过 Csac 辅助 Cd 的去除。在本研究中，我们探索了 Csac 在含 Cd 介质中与微藻（Chlorella）的反应。扫描电子显微镜（SEM）成像、X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、超导脉冲傅里叶变换核磁共振（pulse-FT NMR）和 X 射线光电子能谱（XPS）的结果表明，Chlorella 可以附着在 Csac 形成的微孔中，形成负载 Chlorella 的 Csac@Chlorella 复合吸附剂。此外，复合吸附剂表面含有丰富的功能基团，如-COOH、-OH 和 C-O-C，它们在吸附过程中作为活性位点。与 Csac 相比，Csac@Chlorella 的 Cd 吸附容量明显增强。结果表明，在 pH 8、0.2 g Csac、Chlorella 的 OD 值为 0.1 的条件下，在 1 小时的接触时间内，Cd 的吸附容量达到最大。此外，Cd 吸附过程很好地符合准二级和 Langmuir 吸附等温线模型。这些模型表明，吸附过程主要基于单分子层的化学吸附，同时还存在静电吸引、络合和细胞内吸附等参数。总的来说，这些发现表明，微藻（Chlorella）-Csac-Cd 的相互作用是复杂的，因此将引起广大生物、环境和地球科学领域的兴趣。
