Excellent adsorption of Zn(II) using NaP zeolite adsorbent synthesized from coal fly ash via stage treatment. (10th June 2020)

• Record Type: Journal Article
• Authors: Zhang, Yanan; Chen, Yanguang; Kang, Wei; Han, Hongjing; Song, Hua; Zhang, Chunlei; Wang, Haiying; Yang, Xiuqi; Gong, Xuzhong; Zhai, Changxiu; Deng, Jitong; Ai, Liling
• Is Part Of: Journal of cleaner production. Volume 258(2020)
• Publication Date: 2020-06-10
• Subjects: Coal fly ash -- NaP zeolite -- Sodium salts -- Steric hindrance agents -- Zinc ions -- Adsorption; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2020.120736
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Herein, a novel method for the adsorption of metal ions from sewage by NaP zeolite adsorbent synthesized from stage-treated coal fly ash (CFA) was proposed. The pre-treatment of CFA and grading extraction of silicon and aluminum were explored, and the effects of crystallization parameters and sodium salts on the yield and purity of NaP zeolites were investigated. The characteristics of the zeolite product were measured by a series of characterization methods and the adsorption performance was also evaluated. Optimal treatment parameters were calcination at 800 °C for 3 h with m (CFA)/ m (Na2 CO3 ) = 1:1 and 3 mol/L HCl with m (CFA)/ V (HCl) = 1 g: 10 mL, with high extraction efficiencies (Si: 91.40% and Al: 90.20%) through stage treatment method. NaP zeolite product exhibited higher purity (96.66%) and yield (94.24%) at 120 °C for 8 h with the addition of NaBr (entirely instead of NaOH, the purity was 90.57% and the yield was 87.82%). The effect of organic steric hindrance was connected with its molecular configuration. NaP zeolite with the addition of polyethylene glycol (PEG) at n (Al2 O3 )/ n (PEG) = 1:5 had the highest single-grain dispersion with the smallest grain size (2.13 μm). However, NaP zeolite with the addition of cyclohexanol (CyOH) at n (Al2 O3 )/ n (CyOH) = 1:3 had the largest surface area (80.4 m 2 /g). During the Zn(II) adsorption, the appropriate pH value was identified at 5, and the adsorption process followed the pseudo second-order kinetics and Langmuir isotherm adsorption equations. The thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. NaP zeolite adsorbent exhibited excellent adsorption performance with Zn(II) concentration less than 0.2 ppm in the absorption equilibrium. Moreover, NaP zeolite as an effective adsorbent possessed excellent regeneration. Graphical abstract: Image 1 Highlights: NaP zeolites were synthesized from coal fly ash by grading extraction of Si and Al. Purity and yield of NaP zeolites were improved by regulating the pH of system. Steric hindrance helped regulate the grain size to enhance the adsorption property. The technology was meaningful for utilizing the solid waste and treating the sewage.