Chen Wu, Xie Huijia, Jiang Nan, Guo Xianzhe, Liu Zhuozhuang
College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434023, People's Republic of China; HSE Key Laboratory of Petro China Company Limited (Yangtze University), Jingzhou 434023, People's Republic of China.
College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434023, People's Republic of China; HSE Key Laboratory of Petro China Company Limited (Yangtze University), Jingzhou 434023, People's Republic of China.
Int J Biol Macromol. 2023 Aug 1;245:125498. doi: 10.1016/j.ijbiomac.2023.125498. Epub 2023 Jun 24.
Heavy metal pollution is becoming increasingly serious. Heavy metal pollutants are nonbiodegradable and can be bioenriched through the food chain, and thus, they greatly threaten the environment and human health. Hydrogels, as an ideal adsorbent, have been widely used to treat heavy metal industrial wastewater. Sodium lignosulfonate hydrogel (LS) was prepared by free-radical grafting copolymerization, and nano-FeO particles were loaded in LS by an in-situ precipitation method (FeO@LS). The magnetic properties and adsorption capacity of FeO@LS are closely related to the load capacity of FeO. XRD, FTIR, XPS, SEM, TEM, BET, and TGA analyses of the materials were performed. Subsequently, the removal effect of the typical pollutant Cd in heavy metal-polluted water was studied with FeO@LS as the adsorbent. The influences of the FeO@LS dosage and initial pH were investigated, and the adsorption kinetics and thermodynamics were further explored and discussed. Finally, the adsorption mechanism of FeO@LS on Cd was obtained. Results show that FeO@LS has a more stable spatial network structure than LS, and the pore size, specific surface area and active sites increase. The maximum adsorption capacity can reach 88.00 mg/g when pH = 6 and the dosage of FeO@LS is 1000 mg/L. The adsorption of Cd by FeO@LS conforms to pseudosecond-order kinetics and the Temkin isothermal adsorption model. Further mechanistic investigations show that the sorption of Cd on FeO@LS is mainly attributed to surface complexation, electrostatic attraction and coprecipitation. The coexistence of cations in water will inhibit the adsorption of FeO@LS. FeO@LS has superparamagnetism and a good response to an external magnetic field. The adsorption rate can still reach >60 % after four elutions with NaCl as the eluent. This material can be reused and has good application potential.
重金属污染日益严重。重金属污染物不可生物降解，可通过食物链进行生物富集，因此，它们对环境和人类健康构成了极大威胁。水凝胶作为一种理想的吸附剂，已被广泛用于处理重金属工业废水。通过自由基接枝共聚制备了木质素磺酸钠水凝胶（LS），并采用原位沉淀法将纳米FeO颗粒负载于LS中（FeO@LS）。FeO@LS的磁性和吸附容量与FeO的负载量密切相关。对材料进行了XRD、FTIR、XPS、SEM、TEM、BET和TGA分析。随后，以FeO@LS为吸附剂，研究了其对重金属污染水中典型污染物Cd的去除效果。考察了FeO@LS用量和初始pH的影响，并进一步探讨和讨论了吸附动力学和热力学。最后，得出了FeO@LS对Cd的吸附机理。结果表明，FeO@LS比LS具有更稳定的空间网络结构，孔径、比表面积和活性位点增加。当pH = 6且FeO@LS用量为1000 mg/L时，最大吸附容量可达88.00 mg/g。FeO@LS对Cd的吸附符合准二级动力学和Temkin等温吸附模型。进一步的机理研究表明，Cd在FeO@LS上的吸附主要归因于表面络合、静电吸引和共沉淀。水中阳离子的共存会抑制FeO@LS的吸附。FeO@LS具有超顺磁性且对外加磁场有良好响应。以NaCl为洗脱剂洗脱四次后，吸附率仍可达到>60%。该材料可重复使用，具有良好的应用潜力。
