Evaluation of phosphate removal from aqueous solution using metal organic framework; isotherm, kinetic and thermodynamic study
- 15 Downloads
Phosphate (PO43−) is the main etiological factor of eutrophication in surface waters. Metal organic frameworks (MOFs) are novel hybrid materials with amazing structural properties that make them a prominent material for adsorption.
Zeolitic imidazolate framework 67 (ZIF-67), a water stable member of MOFs, with a truncated rhombic dodecahedron crystalline structure was synthesized in aqueous environment at room temperature and then characterized using XRD and SEM. PO43− adsorption from synthetic solutions using ZIF-67 in batch mode were evaluated and a polynomial model (R2: 0.99, R2adj: 0.98, LOF: 0.1433) developed using response surface methodology (RSM).
The highest PO43− removal (99.2%) after model optimization obtained when ZIF-67 dose, pH and mixing time adjusted to 6.82, 832.4 mg/L and 39.95 min, respectively. The optimum PO43− concentration in which highest PO43− removal and lowest adsorbent utilization occurs, observed at 30 mg/L. PO43− removal eclipsed significantly in the presence of carbonate. The equilibrium and kinetic models showed that PO43− adsorbed in monolayer (qmax: 92.43 mg/g) and the sorption process controlled in the sorption stage. Adsorption was also more favorable at higher PO43− concentration, according to the separation factor (KR) graph. Thermodynamic parameters (minus signs of ∆G°, ∆H° of 0.179 KJ/mol and ∆S° of 44.91 KJ/mol.K) demonstrate the spontaneous, endothermic and physisorption nature of the process.
High adsorption capacity and adsorption rates, make ZIF-67 a promising adsorbent for PO43− removal from aqueous environment.
KeywordsMetal organic frameworks (MOFs) ZIF-67 Adsorption Phosphate RSM Thermodynamic
The authors would like to appreciate the financial support provided by Ilam University of Medical Science, Iran (Grant Number: 974001-14).
Compliance with ethical standards
Conflict of interest
The authors of this article declare that they have no conflict of interests.
- 4.Yin Z, Wan S, Yang J, Kurmoo M, Zeng M-H. Recent advances in post-synthetic modification of metal–organic frameworks: New types and tandem reactions. J Coord Chem. 2017;In Press.Google Scholar
- 13.Yong P, Zhi L, Zhe Z, Xiong-Shi T, Hai L, Chong-Zhi J, et al. Adsorptive removal of phenol from aqueous solution with zeolitic imidazolate framework-67. J Environ Manag. 2016;169(169):167–73.Google Scholar
- 16.Mahvi AH. Ebrahimi SJA-d, Mesdaghinia a, Gharibi H, Sowlat MH. Performance evaluation of a continuous bipolar electrocoagulation/electrooxidation–electroflotation (ECEO–EF) reactor designed for simultaneous removal of ammonia and phosphate from wastewater effluent. J Hazard Mater. 2011;192(3):1267–74.CrossRefGoogle Scholar
- 22.Ahmadian M, Yosefi N, Toolabi A, Khanjani N, Rahimi S, Fatehizadeh A. Adsorption of Direct Yellow 9 and Acid Orange 7 from Aqueous Solutions by Modified Pumice. Asian J Chem. 2012;24(7).Google Scholar
- 30.Dehghan A, Zarei A, Jaafari J, Shams M, Khaneghah AM. Tetracycline removal from aqueous solutions using zeolitic imidazolate frameworks with different morphologies: a mathematical modeling. Chemosphere. 2018.Google Scholar
- 40.Lin J, Wang X, Zhan Y. Effect of precipitation pH and coexisting magnesium ion on phosphate adsorption onto hydrous zirconium oxide. J Environ Sci. 2018(In Press).Google Scholar