Mechanism of dust suppressant by sodium carboxymethyl cellulose grafted acrylic copolymer

Abstract

In order to inhibit dust, a substance C-PAA was synthesized by free radical polymerization using sodium carboxymethyl cellulose and acrylic acid as raw materials and ammonium persulfate as an initiator. The optimal synthesis process was determined by using a single factor experimental method. Quantum chemistry and experiments were used to investigate the chemical synthesis of C-PAA. The results indicate that the active centers of the reaction were at the OH bond of sodium carboxymethyl cellulose, where H was seized by ·SO4-, produced by ammonium persulfate, to form an alkoxyl radical. Concurrently, ·SO4- attacked acrylic acid, resulting in the breakage of the CC bond, creating a CC bond, and combining with the alkoxyl group to create a new ether group that produced the compound C-PAA. The enthalpy change and activation energy of the reaction were −178.40 KJ/mol and −22.59 KJ/mol, respectively, and the infrared absorption peaks of the newly generated fatty ether and the increase in the relative content of the ether group in the final product proved that the preparation of C-PAA was successful. In order to further improve the wetting performance of the dust suppressant, pyrene fluorescence spectrometry was used to determine the critical micelle concentration of the surfactant sodium dodecyl sulfate as 1.5 g/L, and 1.5 g/L sodium dodecyl sulfate was mixed with C-PAA to obtain the dust suppressant SC-PAA. In comparison to the H2O-lignite system, the total number of hydrogen bonds in the SC-PAA-lignite system increased from 2023 to 2405, according to the molecular dynamics results. The rationale is that C-PAA in SC-PAA has a plethora of oxygen-containing functional groups, which enable it to create more hydrogen bonds with H2O as well as amino and hydroxyl groups on the surface of lignite. Due to hydrogen bonding, the dust suppressant is able to gather more water molecules adsorbed on the surface of the lignite. It then utilizes the capillary force of the coal pores to penetrate deeply into the fissures within the coal particles, thereby enhancing the wetting impact on the lignite.