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Characteristics and mechanisms of cadmium adsorption onto biogenic aragonite shells-derived biosorbent: Batch and column studies
- Source :
- Journal of Environmental Management. 241:535-548
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- Calcium carbonate (CaCO3)-enriched biomaterial derived from freshwater mussel shells (FMS) was used as a non-porous biosorbent to explore the characteristics and mechanisms of cadmium adsorption in aqueous solution. The adsorption mechanism was proposed by comparing the FMS properties before and after adsorption alongside various adsorption studies. The FMS biosorbent was characterized using nitrogen adsorption/desorption isotherm, X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, and point of zero charge. The results of batch experiments indicated that FMS possessed an excellent affinity to Cd(II) ions within solutions pH higher than 4.0. An increase in ionic strength resulted in a significant decrease in the amount of Cd(II) adsorbed onto FMS. Kinetic study demonstrated that the adsorption process quickly reached equilibrium at approximately 60 min. The FMS biosorbent exhibited the Langmuir maximum adsorption capacity as follows: 18.2 mg/g at 10 °C Cd2+ > Cu2+ > Cr3+ > Zn2+. For column experiments, the highest Thomas adsorption capacity (7.86 mg/g) was achieved at a flow rate (9 mL/min), initial Cd(II) concentration (10 mg/L), and bed height (5 cm). The Cd(II) removal by FMS was regarded as non-activated chemisorption that occurred very rapidly (even at a low temperature) with a low magnitude of activation energy. Primary adsorption mechanism was surface precipitation. Cadmium precipitated in the primary (Cd,Ca)CO3 form with a calcite-type structure on the FMS surface. A crust of rhombohedral crystals on the substrate was observed by SEM. Freshwater mussel shells have the potential as a renewable adsorbent to remove cadmium from water.
- Subjects :
- Langmuir
Environmental Engineering
0208 environmental biotechnology
chemistry.chemical_element
02 engineering and technology
010501 environmental sciences
Management, Monitoring, Policy and Law
01 natural sciences
Calcium Carbonate
Adsorption
Desorption
Point of zero charge
Waste Management and Disposal
0105 earth and related environmental sciences
Cadmium
Aqueous solution
General Medicine
Hydrogen-Ion Concentration
020801 environmental engineering
Kinetics
chemistry
Chemisorption
Ionic strength
Water Pollutants, Chemical
Nuclear chemistry
Subjects
Details
- ISSN :
- 03014797
- Volume :
- 241
- Database :
- OpenAIRE
- Journal :
- Journal of Environmental Management
- Accession number :
- edsair.doi.dedup.....783ec72b9164d5cc04adb7ef2ee8280a