Incorporation of La/UiO66-NH2 into cellulose fiber for efficient and selective phosphate adsorption

The pollution resulting from excessive phosphorus usage has garnered significant attention. In this study, the cellulose composite fiber was fabricated by immobilizing La doped UiO66-NH2 nanoparticles onto cellulose fiber through a facile in-situ hydrothermal synthesis method. Nanosized UiO66-NH2 particles were uniformly distributed on the CCF, and La doping induced defects in the crystal structure of UiO66-NH2, which provided active sites for phosphate absorption. The composite cellulose fiber materials exhibited fast (1 h) and effective (7.6 mg g-1) adsorption properties to phosphate compare to other adsorption materials. Moreover, the adsorption process for phosphorus were spontaneous and endothermic, which accorded with pseudo-second-order kinetic and Langmuir isotherm models. FTIR and XPS analyses elucidate that chemical bond and electrostatic attraction between Zr/La-O-P play pivotal roles in phosphate capture mechanism. The adsorption was driven by two interaction, namely electrostatic interaction between -NH2 and phosphate and chemical bond of Zr-O-P and La-O-P. Notably, the composite fiber exhibited effective adsorption ability within a wide pH range of 3–7, and excellent selectivity to phosphate under common interfering ions such as SO42-, NO3-, and Cl-. Overall, this research has provided new thinking of La-UiO66-NH2/CCF as a promising phosphate adsorbent possessing favorable adsorption properties, which will facilitate the utilization of cellulose composite fibers in wastewater treatment.