Efficient adsorption of Pb(II) by sodium dodecyl benzene sulfonate intercalated calcium aluminum hydrotalcites: kinetic, isotherm, and mechanisms

• Published in: Environmental science and pollution research international 2022-06, Vol.29 (30), p.46161-46173
• Main Authors: Zeng, Rongying, Tang, Wenqing, Zhou, Qianyi, Liu, Xing, Liu, Yan, Wang, Shuzhan, Chen, Zhen, Yi, Nengzhong, Wang, Zefen, Chen, Jun
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Aluminum; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Benzene; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Hydrocarbons; Ion exchange; Isotherms; Lead; Mathematical models; pH effects; Physical properties; Research Article; Sodium; Sodium dodecylbenzenesulfonate; Sulfonates; Waste Water Technology; Water Management; Water pollution; Water Pollution Control; X ray photoelectron spectroscopy
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-022-19129-7

Two novel adsorbents of CaAl-LDHs and sodium dodecyl benzene sulfonate (SDBS) intercalated CaAl-LDHs (SDBS-CaAl-LDHs) were successfully prepared by co-precipitation. The main composition and physical properties of two samples were characterized by XRD, XPS, FT-IR, TG, and SEM. Batch adsorption experiments were conducted to study the effect of pH, adsorption time, and initial concentration of Pb 2+ . The results showed that the prime adsorption conditions obtained were pH of 5.2 after 60 min with the initial concentration of 300 mg g −1 for CaAl-LDHs and 350 mg g −1 for SDBS-CaAl-LDHs. At 303 K, the adsorption capacities and removal rates of CaAl-LDHs and SDBS-CaAl-LDHs were found to be 456.05 mg g −1 , 91.21% and 682.26 mg g −1 , 97.47%, respectively. For CaAl-LDHs, the kinetic data for Pb 2+ was best fitted with pseudo-2nd-order model, and the adsorption isotherms followed Langmuir and Freundlich isotherm model. The adsorption data of SDBS-CaAl-LDHs can be best described by the pseudo-second-order kinetic and Langmuir model. The Pb 2+ adsorption mechanism on SDBS-CaAl-LDHs was explored by XRD, XPS, and SEM, and the important roles of the electrostatic attraction, precipitation, complexation, and ion exchange were demonstrated. The Langmuir adsorption capacities for SDBS-CaAl-LDHs were 797.63, 828.76, and 854.29 mg g −1 at 293 k, 303 k, and 313 k, respectively. Thus, SDBS-CaAl-LDHs may be a highly economical adsorbent for the treatment of contaminated water.