Enhanced Kinetic Removal of Ciprofloxacin onto Metal-Organic Frameworks by Sonication, Process Optimization and Metal Leaching Study

Abstract

Metal-organic frameworks (MOFs) are currently recognized as unique platforms for environmental studies. This study evaluated the potential of nine MOFs from ZIF-8, ZIF-67, and UIO-66 families for the removal of ciprofloxacin (CIP), a toxic, bio-accumulative, and persistent fluoroquinolone antibiotic. ZIF-67-SO4, with a rhombic crystalline morphology and 1375 m2/g BET surface area, has the highest CIP adsorption efficiency among the studied MOFs. The mathematical sorption model predicted that the highest CIP removal (99.2%) occurs when adsorbent dose, pH, and agitation time are adjusted to 6.82, 832.4 mg/L, and 39.95 min, respectively. Further studies revealed that the CIP adsorbed onto ZIF-67-SO4 in monolayer (qmax: 2537.5 mg/g) and chemisorption controlled the rate of the process. Mass transfer kinetic coefficients improved significantly by sonication at 35 KHz in comparison with mechanical agitation. Thermodynamic parameters (minus signs of ∆G° [7.8 to 14.2], positive signs of ∆H° (58.9 KJ/mol), and ∆S° (0.23 KJ/mol·K)) demonstrated the spontaneous, endothermic, and chemical sorption of CIP. The level of cobalt leached from ZIF-67-SO4 structure varied 1.2–4.5 mg/L, depending on pH, mixing time, and agitation type. In conclusion, the excellent adsorption properties of ZIF-67-SO4 for CIP, made it an outstanding candidate for environmental protection purposes.

Enhanced ciprofloxacin removal from aqueous solution using a chemically modified biochar derived from bamboo sawdust: Adsorption process optimization with response surface methodology

“…Hence, maximum adsorption was obtained at this pH level. Dehghan et al (2019) observed a similar adsorption trend for the CIP using a metal organic framework (MOF). They reported that an increase in pH from 3 to 7.5 increased the adsorption of CIP onto MOF.…”

Zinc and cadmium adsorption from wastewater using hydroxyapatite synthesized from flue gas desulfurization waste

“…Langmuir and Freundlich adsorption isotherms, the most frequently used models to demonstrate liquid phase adsorption equilibrium data, were employed to examine the adsorption behaviors of FGD-HAP. Langmuir equation is expressed as follow (Dehghan et al 2019;Yousefi et al 2021):…”

Recent Progress in Heavy Metal Ion Decontamination Based on Metal–Organic Frameworks

“…The characteristics of MOFs such as large surface areas, permanent porosity, multi-functionalization, changeable structures and open metal sites, are beneficial to a wide range of applications, including gas storage [ 8 , 9 , 10 , 11 ], separation [ 12 , 13 , 14 , 15 , 16 ], catalysis [ 17 , 18 , 19 , 20 , 21 ], sensing [ 22 , 23 ], drug delivery [ 24 , 25 , 26 ], bioimaging [ 27 , 28 ], and proton conduction [ 29 , 30 ]. Recently, MOFs have been shown to be effective in the adsorption of toxic pollutants, such as hazardous metal ions and organic compounds [ 31 , 32 , 33 , 34 ]. The number of articles related to the application of MOFs in different fields from 2011 to 2019 is shown in Figure 1 , according to the statistics provided by the Web of Science, showing an increasing trend in the research on the use of MOFs for the adsorption of heavy metal ions.…”