title: Application of zeolite-activated carbon macrocomposite for the adsorption of Acid Orange 7: isotherm, kinetic and thermodynamic studies.
abstract: In this study, the adsorption behavior of azo dye Acid Orange 7 (AO7) from aqueous solution onto macrocomposite (MC) was investigated under various experimental conditions. The adsorbent, MC, which consists of a mixture of zeolite and activated carbon, was found to be effective in removing AO7. The MC were characterized by scanning electron microscopy (SEM), energy dispersive X-ray, point of zero charge, and Brunauer-Emmett-Teller surface area analysis. A series of experiments were performed via batch adsorption technique to examine the effect of the process variables, namely, contact time, initial dye concentration, and solution pH. The dye equilibrium adsorption was investigated, and the equilibrium data were fitted to Langmuir, Freundlich, and Tempkin isotherm models. The Langmuir isotherm model fits the equilibrium data better than the Freundlich isotherm model. For the kinetic study, pseudo-first-order, pseudo-second-order, and intraparticle diffusion model were used to fit the experimental data. The adsorption kinetic was found to be well described by the pseudo-second-order model. Thermodynamic analysis indicated that the adsorption process is a spontaneous and endothermic process. The SEM, Fourier transform infrared spectroscopy, ultraviolet-visible spectral and high performance liquid chromatography analysis were carried out before and after the adsorption process. For the phytotoxicity test, treated AO7 was found to be less toxic. Thus, the study indicated that MC has good potential use as an adsorbent for the removal of azo dye from aqueous solution.
authors: Department of Biosciences and Health Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
authors: Chi Kim
authors: CK
authors: Lim
authors: Hui Han
authors: HH
authors: Bay
authors: Chin Hong
authors: CH
authors: Neoh
authors: Azmi
authors: A
authors: Aris
authors: Zaiton
authors: Z
authors: Abdul Majid
authors: Zaharah
authors: Z
authors: Ibrahim
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000032:analysis / Q000737:chemistry*; D001557:Benzenesulfonates / Q000032:analysis / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D004058:Diffusion; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D017641:Zeolites
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D002606:Charcoal; D062065:Wastewater; D014874:Water Pollutants, Chemical; D017641:Zeolites; C014722:2-naphthol orange
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