Hydroxyethyl Cellulose Gel-Loaded Melamine/Terephthalaldehyde Mesoporous Materials for p-Nitrophenol Removal in Low-Concentration Wastewater

As an important intermediate, p -nitrophenol has been widely used in the production of various chemicals, including pharmaceuticals, insecticides, and dyes, etc. However, it exhibits significant ecological toxicity and has a tendency to accumulate in organisms, even at very low concentrations. Therefore, it is essential to remove p -nitrophenol as thoroughly as possible from wastewater before discharging it into the environment. Among various treatment methods, physical adsorption stands out as a safe, reliable, and widely applicable approach, particularly suitable for small-scale water treatment applications. In this study, a melamine/terephthalaldehyde-based material (PMT) with a rich mesoporous structure was synthesized. The presence of abundant nitrogen elements within the material’s structure enhances its adsorption capacity for p -nitrophenol. Subsequently, PMT was dispersed as the dispersed phase into a hydrogel (HGel) structure through post-polymerization, which improved the material’s stability during use. Experimental results demonstrated that the gel composite material achieved a 97.6% adsorption removal rate for p -nitrophenol-contained wastewater. Moreover, after six cycles of reuse, the material retained an adsorption removal rate of 84.2%, highlighting its excellent adsorption performance and reusability.