Efficient selective separation of dyes by TA-MoS2/Calcium silicate hydrate composite filtration system

Abstract

The effective separation and resource recovery of composite dye wastewater pose significant challenges in the treatment of organic dye wastewater. Composite dye wastewater treatment faces challenges in separation and resource recovery. We developed a novel filtration system using calcium silicate hydrate and tannic acid-grafted MoS₂ nanosheets. The system achieves high water permeance and exceptional dye separation efficiency. The system attains a water permeance of 1523 L m⁻² h⁻¹·bar⁻¹. Notably, the separation efficiency for methylene blue reaches 99.6 %, while that for methyl orange is only 8.9 %. Importantly, the separation efficiency for composite dyes remains above 94 % after 11 consecutive treatment of simulated dye wastewater. The high water permeance in the composite filtration system is attributed to the synergistic effect between the water transport channels of porous calcium silicate hydrate and the layer spacing of molybdenum disulfide nanosheets, which is regulated by tannic acid. The high filtration efficiency is primarily due to the adjustment of the interlayer spacing and surface charge modification of molybdenum disulfide by tannic acid grafting, as well as the synergistic effect of electrostatic adsorption by the nanofiltration membrane and calcium silicate hydrate. Furthermore, the composite filtration system demonstrates excellent stability, highlighting its potential for repeated use.