Chunhakowit Parichart, Phabjanda Yada, Aunwisat Atchara, Busayaporn Wutthikrai, Songsrirote Kriangsak, Prayongpan Pornpimol
Department of Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok, 10110, Thailand.
Synchrotron Light Research Institute, Nakhon Ratchasima, 30000, Thailand.
Sci Rep. 2024 Nov 16;14(1):28259. doi: 10.1038/s41598-024-80024-x.
An effective tannic acid-incorporated polyvinylpyrrolidone/polyvinyl alcohol composite hydrogel with high-potential sorption capacity was developed for the removal of copper from aqueous solution. The composite hydrogel exhibited pH-dependent swelling, in which swelling and shrinking occurred reversibly with adjustment of the pH of the medium. At pH 4, the maximal adsorption capacity for copper at 30 °C was 297.0 mg g, and the adsorbent dose was 4 g L. The adsorption kinetics were best fitted with a pseudo-second order kinetic model. The adsorption behavior was well predicted by the Freundlish isotherm. The thermodynamics parameters indicated a spontaneous and exothermic reaction with an increase in the entropy of the system. The chemical changes in the film structure before and after adsorption treatment were characterized by Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). The FTIR, XPS and XAS results confirmed that Cu bound to the oxygens in the -OH, C = O and N-(C = O)- functional groups on the T-HD. XAS analysis revealed the chemical composition and molecular geometry of the adsorbed copper ions. The single-solute adsorption and coadsorption mechanisms, which provide insight into cobalt-copper, nickel-copper, or nickel-cobalt-copper complex solutions, were investigated. The composite hydrogel exhibited excellent regeneration ability in EDTA solution. Notably, the adsorbent retained an adsorption efficiency exceeding 87% even after five regeneration cycles. On the basis of both adsorbent characteristics and adsorption performance, it was determined that the composite hydrogel has the potential to be used as a platform for developing materials to treat wastewater containing high levels of metal contaminants such as those from the electroplating industry.
开发了一种具有高吸附潜力的有效含鞣酸聚乙烯吡咯烷酮/聚乙烯醇复合水凝胶，用于从水溶液中去除铜。该复合水凝胶表现出pH依赖性溶胀，其中随着介质pH值的调节，溶胀和收缩可逆地发生。在pH为4时，30℃下对铜的最大吸附容量为297.0mg/g，吸附剂用量为4g/L。吸附动力学最符合准二级动力学模型。吸附行为通过Freundlish等温线得到了很好的预测。热力学参数表明这是一个自发的放热反应，系统熵增加。通过扫描电子显微镜（SEM）、傅里叶变换红外（FTIR）光谱、X射线光电子能谱（XPS）和X射线吸收光谱（XAS）对吸附处理前后膜结构的化学变化进行了表征。FTIR、XPS和XAS结果证实，Cu与T-HD上-OH、C=O和N-(C=O)-官能团中的氧结合。XAS分析揭示了吸附的铜离子的化学组成和分子几何结构。研究了单溶质吸附和共吸附机制，这为深入了解钴-铜、镍-铜或镍-钴-铜复合溶液提供了依据。该复合水凝胶在EDTA溶液中表现出优异的再生能力。值得注意的是，即使经过五个再生循环，吸附剂的吸附效率仍保持在87%以上。基于吸附剂特性和吸附性能，确定该复合水凝胶有潜力用作开发处理含高浓度金属污染物废水（如来自电镀行业的废水）材料的平台。
