Highly efficient and stable catalysis of p-nitrophenol via silver/lignin/polyacrylic acid hydrogel.

As the second largest natural polymer in nature, lignin has a large amount of reserves and has important practical application value, which has attracted increasing attention. Ag@LPAH, a nanometer silver catalyst with a 3D structure, was successfully prepared in a simple operation. In batch experiment and fixed-bed experiment, it showed excellent catalytic degradation ability and stability of 4-NP. Thanks to the large number of carboxyl groups present in the lignin-polyacrylic acid hydrogel, the silver nanoparticles are well controlled to grow with no agglomeration. Ag@LPAH-20 exhibited optimal catalytic performance and stability, requiring only 123 s to complete the reaction and maintaining 99% catalytic efficiency after 10 cycles. In addition, the catalytic efficiency can be maintained over 90% for more than 120 min in fixed bed experiment.