Overview
Hamad and Ibrahim fabricated two bio-based adsorbent composites, CS@Fe-PA and MgO@Pp, and tested their removal of cadmium and copper ions from aqueous solutions. This is mitigation and wastewater-remediation evidence with extractable adsorption efficiencies and capacities; it is not consumer-product occurrence evidence.
Key numbers
The abstract reports optimum test conditions of pH 5 for Cu(II), pH 6 for Cd(II), 120 min contact time, 0.2 g adsorbent dosage, and 50 mg/L initial concentration for each metal in the main optimization study.
At those conditions, MgO@Pp had higher headline removal and capacity than CS@Fe-PA:
| Composite | Cu(II) removal | Cd(II) removal | Cu(II) capacity | Cd(II) capacity |
|---|---|---|---|---|
| MgO@Pp | 98.2% | 96.4% | 333.3 mg/g | 200 mg/g |
| CS@Fe-PA | 97.2% | 89.2% | 250 mg/g | 142 mg/g |
Dose-response results showed CS@Fe-PA removal increasing from 73.4% to 96.06% for Cu(II) and from 58.4% to 89.6% for Cd(II) as dosage increased from 0.2 to 1.2 g/L. MgO@Pp increased from 77.6% to 98.8% for Cu(II) and from 69.4% to 97.07% for Cd(II) over the same dosage range.
Contact-time optimization reached near-equilibrium at 120 min. The paper reports 15 min removals of 78.04%, 55.4%, 66.8%, and 50.3% for Cu(II) and Cd(II) in the MgO@Pp and CS@Fe-PA composites, respectively, increasing at 120 min to 98.2%, 97.5%, 96.7%, and 90.09%.
For initial concentrations from 30 to 100 ppm, MgO@Pp removal decreased from 98.02% to 81.2% for Cu(II) and from 96.4% to 68.2% for Cd(II). CS@Fe-PA removal decreased from 97.2% to 73.4% for Cu(II) and from 89.7% to 32.08% for Cd(II).
Kinetic fitting favored pseudo-second-order behavior for most fits. Table 1 reports pseudo-second-order calculated qe values of 45.4 and 47.6 mg/g for Cu(II) and Cd(II) in CS@Fe-PA, and 47.6 and 50 mg/g for Cu(II) and Cd(II) in MgO@Pp.
Methods (brief)
The authors synthesized MgO nanoparticles using mulberry-leaf extract and pomegranate peel, and prepared a chitosan/Fe(III)/Padina pavonica composite. Batch tests used 100 mL metal solutions in 250 mL flasks, Cu(II) and Cd(II) concentrations of 30-100 ppm, adsorbent dosages from 0.2 to 1.2 g, 210 rpm agitation, 25 degrees C, and 120 min contact time unless the tested variable was contact time.
Metal removal was calculated from initial and final solution concentrations, and equilibrium adsorption capacity was calculated from initial concentration, equilibrium concentration, solution volume, and adsorbent mass. Characterization included FTIR, SEM/EDX, XRD, TGA, and XPS. The source reports dissolved Cu(II) and Cd(II), not food, textile, fabric, or finished-product concentrations.
Related evidence
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