College of Natural Resources and Environment, Joint Institute for Environmental Research & Education, South China Agricultural University, Guangzhou 510642, China.
Shenzhen Dayushu Technology Co., Ltd, Shenzhen 518000, China.
J Hazard Mater. 2021 Aug 15;416:126262. doi: 10.1016/j.jhazmat.2021.126262. Epub 2021 May 29.
Cadmium (Cd) and tetracycline (TC) cause serious environmental risks. Nanomaterials have been extensively applied for environmental remediation. The size and content of nanoparticles directly affect the removal of contaminants. However, size regulation and quantitative determination of nanoparticles cannot be easily realized. In this study, hydrogels with different polymerization degrees were prepared by adjusting the contents of acrylamide (AM) and sodium lignosulfonate polymeric monomers. Ferrous sulfide (FeS) nanoparticles of different sizes were synthesized in situ within the hydrogels. The nanoparticle size decreased from 600 to 200 nm with increasing hydrogel polymerization degree, and an incomplete crystalline state was observed at the highest polymerization degree. By combining energy dispersive spectroscopy (EDS) images with the maximum between-class variance (Otsu) method, the content of nanoparticles was calculated to be 7.81%, 15.05%, 22.62%, 27.10%, 21.97%, and 23.95%. The distribution state of FeS compounds was also obtained. A low polymerization degree resulted in high FeS dispersal, and a high polymerization degree affected the uniformity distribution based on irregular ion diffusion. The obtained nanocomposites with different polymerization degrees were applied to the removal of Cd and TC in water. The removal capacity for both contaminants revealed a trend of initially increasing and then decreasing. The initial increase was related to the increasing content and decreasing size of the FeS nanoparticles, while the following decrease was due to the decreasing content and incomplete crystallization of the FeS nanoparticles. Overall, changing the proportion of polymeric monomers is an effective way to regulate particle size, and the Otsu method combined with EDS mapping images is a feasible method for calculating the content of nanoparticles.
镉（Cd）和四环素（TC）会造成严重的环境风险。纳米材料已广泛应用于环境修复。纳米颗粒的大小和含量直接影响污染物的去除。然而，纳米颗粒的尺寸调节和定量测定不易实现。本研究通过调整丙烯酰胺（AM）和木质素磺酸钠聚合单体的含量，制备了不同聚合度的水凝胶。在水凝胶内原位合成了不同尺寸的硫化亚铁（FeS）纳米颗粒。随着水凝胶聚合度的增加，纳米颗粒的尺寸从 600nm 减小到 200nm，在最高聚合度时观察到不完全结晶状态。通过将能量色散光谱（EDS）图像与最大类间方差（Otsu）法相结合，计算出纳米颗粒的含量分别为 7.81%、15.05%、22.62%、27.10%、21.97%和 23.95%。还获得了 FeS 化合物的分布状态。低聚合度导致 FeS 分散性高，而高聚合度则基于不规则的离子扩散影响均匀分布。将不同聚合度的所得纳米复合材料应用于水中 Cd 和 TC 的去除。对两种污染物的去除能力呈现出先增加后减少的趋势。最初的增加与 FeS 纳米颗粒含量的增加和尺寸的减小有关，而随后的减少则与 FeS 纳米颗粒含量的减少和不完全结晶有关。总之，改变聚合单体的比例是调节颗粒尺寸的有效方法，而 Otsu 法结合 EDS 映射图像是计算纳米颗粒含量的可行方法。
