Design of Fabricated Building Wall Under Nano-Magnetic Fly Ash and Its Prevention and Effect on Heavy Metal Pollution

Abstract

This research aims to analyse the design of fabricated building wall based on nano-magnetic fly ash (N-M fly ash) and its prevention and control effect on heavy metal pollution. The fly ash is added to ferric tetrachloride reaction solution to react for different periods after pre-treated with sodium hydroxide, and made into spherical particles. The spherical particles are magnetized with a strong magnetic field to prepare magnetic fly ash particles, and the N-M fly ash is prepared by mechanical crushing. Then, it is applied to the frame column material of the fabricated building wall, and the heavy metal ion adsorption test is performed. Infrared characterization results show that the absorption peak of N-M fly ash at 3000 cm−1 is greater than that at 3500 cm−1. However, there is no obvious stretching vibration peak at 2000 cm−1. The adsorption test reveals that when the reaction time is less than 60 min, the adsorption efficiency of heavy metal ions rises fast. When the reaction time is longer than 120 min, the accelerated rate of adsorption efficiency gradually decreases. The normal pressure heat capacities of fly ash before and after magnetization and N-M fly ash are 1150 J/(Kg*k), 950 J/(Kg*k), and 800 J/(Kg*k), respectively. The coefficients of thermal expansion are 6(e−6)1/K, 15(e−6)1/K, and 9(e−6)1/K, respectively. In short, the optimal reaction time and reaction temperature for the preparation are 120 min and 60 °C, respectively. The heat transfer effect of N-M fly ash is slow and uniform, the material foams uniformly, and it has good thermal insulation performance. Moreover, N-M fly ash has good adsorption performance for heavy metal ions, and the adsorption performance is best when the solution pH = 5.