Immobilization of zirconium-modified activated carbon in an alginate matrix for the removal of atrazine: Preparation, performances and mechanisms
Yiyan Tang, Danxia Liu, Huijun He, Jianmei Zou, Dunqiu Wang, Xiaolong Yang, Lin Zhang, Caixia Yang
Abstract
As an organic herbicide widely used in agriculture, atrazine has the characteristics of environmental persistence, high mobility and long half-life period, posing potential risks to the ecological environment. The materials commonly used to remove atrazine are powdered activated carbon and its modified materials, which have problems such as difficulty in recycling and secondary contamination. In order to solve the above problems, in this study, a new functional material EI-Zr@AC was prepared by immobilizing zirconium-modified activated carbon powder (Zr@AC) in an alginate matrix via the embedding immobilization (EI) technique, and was employed for removing atrazine in water. At the optimal preparation conditions of 2.5% sodium alginate, 4.0% CaCl2, 1.0% Zr@AC and 2.0% bentonite, the prepared EI-Zr@AC beads had the characteristics of high porosity, dense reticulation, and a large number of functional groups with optimal mechanical strength and mass transfer properties. When solution pH 3.0, temperature 25°C, and EI-Zr@AC dosage of 16 g/L, the removal efficiency of atrazine by EI-Zr@AC was 91.9%. It showed that the atrazine removal by EI-Zr@AC was mainly the chemisorption and multimolecular layer adsorption. In addition, the EI-Zr@AC could be recycled after simple recycling method, and the removal of atrazine at 5.0 mg/L by the beads was still 55.5% after five cycles, and the structure of the beads remained intact and Zr ion leaching rate was very low. The results showed that EI-Zr@AC was a kind of environmental remediation material with high application value.