Abstract
Zirconium oxide/activated carbon (Zr3O/AC) composite was synthesized to remove methylene blue (MB) and crystal violet (CV) from the aqueous medium. The Zr3O/AC sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analyses (EDS), Raman spectroscopy (RS), BET surface area, and Fourier transform infrared spectroscopy (FTIR). XRD profiles confirmed the successful synthesis of the zirconium oxide/activated carbon composite. SEM images showed multideveloped walls with irregular particle size with channel arrays. The nitrogen physisorption combines I and IV types with a calculated BET surface area of 1095 m2/g. Raman spectrum illustrated a disorder of both crystalline structure and the graphitic structure. The adsorption was better fitted to the pseudo-second-order (PSO) kinetic model. Langmuir model fitted better the experimental results of MB adsorption, whereas the CV was better consistent with the Freundlich model. The obtained results suggested that the MB and CV adsorption might be influenced by the mass transfer that involves multiple diffusion steps. The maximum adsorption capacities are 208.33 and 204.12 mg/g for MB and CV, respectively. The MB and CV removal mechanisms were proposed, and statistical optimization was performed using central composite design combined with the response surface methodology.
Highlights
Nowadays, many industrial activities such as coloring, textile, cosmetic, paper, food, paint, printing, and pharmaceuticals are considered a big concern from the environmental point of view as many hazardous synthetic dyes are generally produced [1]. ese pollutants are regarded as reactive, acid, and basic and are very harmful to environment including vegetation, humans, and animals [2]
Adsorption is the most effective and broadly utilized approach due to its many advantages being the relatively low cost and ease implementation of the operation process [9] and the effectiveness of the adsorption process that primarily depends on the performance of the adsorbent mass transfer and thermodynamics
The almond shell was mixed with KOH solution (Sigma-Aldrich, 98%), 10 g of KOH (Sigma-Aldrich, 90%), with 20 g of almond shell and 100 mL of distillated water to obtain a solution which was heated at 60°C for 12 h and dried at 110°C. en, the dried sample was pyrolyzed under N2 flow (200 cm3/min) at 300°C for 2 h and at 800°C for 3 h at a heating rate of 10°C/min. e Zr3O/AC composite was prepared by impregnation of 20 wt.% of zirconium oxynitrate ZrO(NO3)2·xH2O (Sigma-Aldrich, 99%) on the prepared activated carbon after 6 hours of stirring at room temperature
Summary
Many industrial activities such as coloring, textile, cosmetic, paper, food, paint, printing, and pharmaceuticals are considered a big concern from the environmental point of view as many hazardous synthetic dyes are generally produced [1]. ese pollutants are regarded as reactive, acid, and basic and are very harmful to environment including vegetation, humans, and animals [2]. Various processes are effectively investigated for the removal and elimination of pollutants like chemical precipitation, adsorption, membrane filtration, biological treatment, and photocatalytic degradation [7, 8]. Among these techniques, adsorption is the most effective and broadly utilized approach due to its many advantages being the relatively low cost and ease implementation of the operation process [9] and the effectiveness of the adsorption process that primarily depends on the performance of the adsorbent mass transfer and thermodynamics. Traditional adsorbents including carbonaceous materials, metal nanoparticle oxides, and polymer resins suffer from either low adsorption capacities or low efficiency [10,11,12,13,14,15,16]. erefore, in the general framework of environmental and waste management, there is a need to synthesize environmental recyclable and friendly materials with better
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