Synthesis of waterborne polyurethane-humic acid cross-linked biomass porous materials for the adsorption of methylene blue

A series of adsorbent materials (WPU-HAx-y) with a three-dimensional porous structure, green sustainability, and excellent performance were prepared and evaluated for the removal of methylene blue using nontoxic and environmentally friendly waterborne polyurethane as the matrix material and humic acid, a biomass material, as the functional material. The newly synthesized adsorbents were characterized by infrared spectroscopy, scanning electron microscopy, specific surface area, and thermogravimetric. The effects of contact time (0-8 h), starting concentration (10-100 mg center dot L-1), pH (3-11), solution temperature (30-60 degrees C), and coexisting ions (Ca2+, Na+, K+, Mg2+) on the performance were investigated. Pseudo-first-order, pseudo-second-order, elovich, and intra-particle diffusion models were used to analyze the adsorption kinetics; the Langmuir, Freundlich, Temkin, and Dubin-Radushkovich adsorption isotherms were evaluated; and the adsorption behavior of the adsorbent materials was found to be more appropriate for the pseudo-second-order model for chemical pollutant removal than the Langmuir model, which depends on monolayer adsorption. WPU-HA2-3 stood out with a maximum adsorption capacity of 813.0081 mg center dot g(-1) fitted to the pseudo-second-order and 309.2832 mg center dot g(-1) fitted to the Langmuir model, showing superior adsorption performance and regenerability. (c) 2023 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.