A novel nCP-PVA@ACA composite with core–shell structure for efficient formaldehyde removal from air

Abstract

Removing formaldehyde from indoor environments is crucial for the health of residents. However, developing a highly efficient and cost-effective material that is safe and stable and capable of continuously removing formaldehyde from ambient air is challenging. In this study, an environmentally friendly plant composite active calcium alginate gel (nCP-PVA@ACA) was prepared by fixing slow-release nanosized calcium peroxide (nCP-PVA) and active components from cactus stems into a three-dimensional network structure of a calcium alginate gel. The microscopic morphology, chemical composition, and structure of nCP-PVA@ACA were characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and Brunauer-Emmett-Teller. In the purification column, nCP-PVA@ACA was used as a filler, which effectively removed formaldehyde from the airflow. The results indicate that nCP-PVA was well dispersed and encapsulated by the calcium alginate gel. The formaldehyde removal efficiency of nCP-PVA@ACA ranged from 90.56 % to 98.51 % when the formaldehyde concentration in the air was in the range of 0.146–0.984 mg·m⁻³, with a maximum removal capacity of 89.31 mg·kg⁻¹ (based on the dry weight of Na alginate). After 3.0 h of continuous purification, the formaldehyde concentration in the treated airflow was reduced to 0.020–0.053 mg·m⁻³, which was significantly lower than the recommended limit of 0.08 mg·m⁻³ of formaldehyde in ambient air. The synergistic effects of plant active components and slow-release nCP are key to effective formaldehyde removal. This study highlights the potential of calcium peroxide for air pollution control, providing new insights and theoretical support for their applications.