Single and multi-component adsorptive removal of bisphenol A and 2,4-dichlorophenol from aqueous solutions with transition metal modified inorganic–organic pillared clay composites: Effect of pH and presence of humic acid

Abstract

Pillared clay based composites containing transition metals and a surfactant, namely MAlOr-NaBt (Bt=bentonite; Or=surfactant; M=Ni(2+), Cu(2+)or Co(2+)), were prepared to study selectivity and capacity toward single and multiple-component adsorption of bisphenol A (BPA) and 2,4-diclorophenol (DCP) from water. Tests were also performed to account for the presence of natural organic matter in the form of humic acid (HA). Equilibrium adsorption capacities for single components increased as follows: NaBt<Al-NaBt<AlOr-NaBt<MAlOr-NaBt. The observed equilibrium loadings were ca. 5 and 3mgg(-1) for BPA and DCP, respectively, at neutral pH conditions and ambient temperature, representing an ordered of magnitude increase over the unmodified pillared clay capacities. Inclusion of the transition metal brought an increase of nearly two-fold in adsorption capacity over the materials modified only with surfactant. The MAlOr-NaBt adsorbents displayed remarkable selectivity for BPA. Multi-component fixed-bed tests, however, revealed competition between the adsorbates, with the exception of the CuAlOr-NaBt beds. Inclusion of HA, surprisingly, enhanced the phenols adsorption capacity. Preliminary regeneration tests suggested that the adsorbent capacity can be recovered via thermal treatment or by washing with alkaline solutions. The former strategy, however, requires surfactant replenishment. More complex schemes would be needed to deal with absorbed HA.

A Novel Inorganic Ni–La2O3 Composite with Superfast and Versatile Water Purification Behavior

“…The BPA uptake rate constant of NLO is 2.097 g mg –1 min –1 , which is 200 times higher than that of NAC (Figure ) and orders of magnitude higher than other studied absorbents (Figure ). To our knowledge, the rate constant in our work is the highest reported for BPA or other micropollutants uptake by zeolites or chemically modified natural materials, carbon and graphene based absorbents, oxides and nanocomposites, activated carbons, and chitosan under the similar experimental conditions, demonstrating that the NLO nanofibers meet the demand for an instant water purification technique. − ,− …”

Comparison of chemical, ultrasonic and thermal regeneration of carbon nanotubes for acetaminophen, ibuprofen, and triclosan adsorption

“…As stated in the literature, four types of physico-chemical interactions, including p-p bond interactions, electrostatic interactions, hydrophobic interactions, and hydrogen-bonding interactions govern CNT adsorption of PPCP compounds. 27,28 As found in the previous studies, CNT adsorption of IBU and TCS is dominated by strong p-p bond interactions between the PPCP molecules and the CNT surfaces, and this effect becomes stronger as the number of aromatic rings in PPCP structures increases. Furthermore, TCS adsorption may also be enhanced by hydrophobic interactions due to the strong hydrophobicity possessed by the compound.…”

Synthesis of robust flexible polyethersulfone ultrafiltration membranes supported on non-woven fabrics for separation of NOM from water

“…HA is said to form as a result of the culmination of condensation polymerisation reactions, amino acid sugar interactions, lignin biodegradation, and animal and plant decay (Ortiz-Martínez et al, 2016). The dangers of HA in water manifest as a result of the use of disinfection processes such as chlorination.…”