Ultraviolet Radiation-Assisted Preparation of a Novel Biomass Fiber to Remove Cadmium from Wastewater

Abstract

The heavy metal adsorbents developed based on biomass resources have valuable application prospects due to the characteristics of rich sources, renewability and low cost. In the present work, a carboxyl functioned loofah fiber (LF@AA) was synthesized via UV-induced polymerization, and its adsorption capacity for cadmium (Cd2+) was investigated systematically. This modification resulted in the effective combination of a loofah fiber template and polyacrylic acid (PAA), which promoted its adsorption of Cd2+ to significantly increase to 339.3 mg·g−1, and the applicable pH range was 4.0~7.0. Furthermore, the adsorbability of LF@AA remained stable at a high level after eight consecutive cycles. The adsorption kinetics and isotherm parameters revealed that the adsorption characteristics of cadmium conformed to the Weber–Morris and pseudo-second-order kinetics equations, and the adsorption process of cadmium conformed to Redlich–Peterson and Langmuir models. In addition, consequences of EDS, FTIR, and Zeta potential analysis reflected that the main adsorption mechanism should be ion exchange. Cd2+ was drawn to the adsorbent surface by electrostatic binding, and ion exchange occurred to form a bidentate chelate. This study suggests that it is reasonable and feasible to use natural biomass materials to develop efficient adsorbents to treat heavy metal pollution in wastewater.