Adsolubilization Of Aromatic Compounds From Aqueous Solution By Surfactant Intercalated Zn₂Al Layered Double Hydroxides

In this work, anionic surfactants dodecylbenzenesulfonate (DBS) and dodecylsulfate (DS)、dodecylsulfonate(DSO) intercalated Zn2Al layered double hydroxides (DBS-LDH and DS-LDH、DSO-LDH) were prepared by one step co-precipitation methods and as adsorbents removing hydrophobic aromatic compounds 2,4,6-trichlorophenol(2,4,6-TCP) and furan from aqueous solutions. Batch adsolubilization experiments were conducted to study several influence factors on 2,4,6-TCP and furan removal, such as adsorption time, pH, temperature, dosage of adsorbents and so on. The adsorption kinetics and equilibrium isotherm models were studied. The structures of adsorbents were characterized by FT-IR and XRD, the concentration of 2,4,6-TCP and furan was quantified by UV and HPLC. The mechanisms of adsorption were also studied.The adsorption study of 2,4,6-TCP showed that when reached adsorption equilibrium about 120 min, DBS-LDH and DS-LDH have better adsorption capacities of 166.8 mg/g and 96.7 mg/g at 298 K and under pH= 3, respectively. When the adopted adsorbents dosage were 7-9 g/L, the removal percentage on 2,4,6-TCP adsorption could reach about 80% respectively. DBS-LDH presented better adsolubilization property than that of DS-LDH. The adsorption kinetics was found to follow the pseudo-second-order model and. The equilibrium isotherms for organic contaminants uptake were fitted well with the linear model and the spontaneous physical adsorption processes are verified by the negative value of AG0. The LDH-based adsorbents still have good adsorption performance after 10 adsorption cycles.The study of adsorption furan showed that when reached adsorption equilibrium at about 240 min, DS-LDH、DSO-LDH and DBS-LDH have better adsorption capacities were 389.2 mg/g、360.4 mg/g、345.7 mg/g at 298K and under a wide pH range, respectively. The adsorption kinetics for adsorbents were found to follow the pseudo-second-order model. For DS-LDH、DSO-LDH, when the adopted adsorbents dosage were 2.6-4.0 g/L, the removal percentage on furan adsorption can reach above 95% respectively.The equilibrium isotherms for organic contaminants uptake were fitted well with the Freundlich model and spontaneous physical adsorption processes were verified by the negative value of △G0.