Key Laboratory of Poyang Lake Environment and Resource Utilization (Nanchang University) of Ministry of Education, Environmental Testing Center of Nanchang University, School of Resource, Environmental and Chemical Engineering, Nanchang University, Nanchang 330031, Jiangxi, PR China. Electronic address: [Email]
The effects of co-existing anions (NO3- or SO42-) on the removal of sodium dodecylsulfate (SDS), representing anionic organic pollutants, by Ca-based layered double hydroxide (CaAl-LDH-Cl) are investigated to provide fundamental insights on the ionic surfactant removal in the presence of co-existing anions, and facilitate the establishment of a practical and advanced water treatment for environmental remediation. The SO42- system shows higher adsorption capacity (4.43 mmol·g-1) and larger d-spacing of adsorption resultant (3.4 nm) than the control system with no co-existing anion (3.64 mmol·g-1, 3.25 nm) and the NO3- system (3.82 mmol·g-1, 3.27 nm). The macroscopic and microscopic analyses reveal that, NO3- had a little influence on the SDS removal due to strong electrolysis, while SO42- could significantly promote the SDS removal. Moreover, the reaction mechanism varies under different molar ratios of DS-/SO42-.