Synthesis and characterization of alumina-grafted acrylic acid monomer and polymer and its adsorption of phenol and p-chlorophenol

• Published in: Desalination and water treatment 2019-05, Vol.150, p.192-203
• Main Authors: Sultan, Maha T., Al-Lami, Hadi S., Al-Dujiali, Ammar H.
• Format: Article
• Language: English
• Subjects: Adsorption; Grafting alumina; Isotherms; Particle size; Phenols
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2019.23593

Aluminum oxide (ALO) was grafted by acrylic acid monomer (AlO-AM) and then, it was polymerized to produce alumina grafted poly(acrylic acid) (AlO-AP). The prepared AlO-AM and AlO-AP were characterized by Fourier-transform infrared, differential scanning calorimetry , thermogravemetric analyzer and particle size distribution. Adsorption equilibrium isotherms, adsorption kinetics and thermodynamic studies of the batch adsorption process were used to examine the fundamental adsorption properties of phenol (P) and p-chlorophenol (PCP). The experimental equilibrium adsorption data were analyzed by three widely used two-parameters Langmuir, Freundlich and Dubinin- Radushkevich isotherms. The maximum P and PCP adsorption capacities based on the Langmuir isotherm were calculated at 56.818, 78.741, 92.593, 80.002, 103.579 and 131.579 mg/g for P and PCP onto ALO, AlO-AM and AlO-AP, respectively. The experimental kinetic data were analyzed by using Pseudo-first order and pseudo-second order kinetic models. A comparison of the kinetic models on the overall adsorption rate showed that the adsorption system can be best described by the pseudo-second order kinetics. Based on the calculated thermodynamic parameters such as enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy changes (ΔG°). The negative ΔG° and ΔH° values indicated that the adsorption of P and PCP by AlO-AM and AlO-AP adsorbent was feasible, spontaneous and the process was exothermic in nature.