OPTIMIZING COPPER AND ARSENIC ADSORPTION WITH CHITOSAN-ZEOLITE BEADS

OPTIMIZING COPPER AND ARSENIC ADSORPTION WITH CHITOSAN-ZEOLITE BEADS

Abstract:

This study focuses on the optimization of process parameters for the effective adsorption of copper and arsenic ions from simulated wastewater using chitosan-based adsorbents, including chitosan beads and chitosan-zeolite composite beads. The adsorbents were synthesized under varying conditions of acidity and alkalinity using acetic acid and sodium hydroxide solutions. Characterization techniques such as X-Ray Diffraction, Brunauer Emmett Teller analysis, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy were employed to assess the prepared adsorbents. The Scanning Electron Microscopy (SEM) analysis revealed that the chitosan-zeolite composite beads exhibited uniform cubic crystals with a smooth, flaky surface distributed evenly throughout the composite, while the chitosan beads displayed a relatively rough surface with irregular shapes and some agglomerated particles. The mean crystallite sizes were determined as 41.64 nm for Chitosan-Zeolite and 74.45 nm for Chitosan beads. The BET analysis indicated surface areas of 376.40 m²/g for Chitosan beads and 691.10 m²/g for Chitosan-Zeolite.

Through the implementation of a central composite design, the impact of various parameters—such as adsorbent dosage, initial concentration, temperature, and time—on the adsorption of copper and arsenic from the simulated wastewater was investigated. Optimal conditions were determined for each adsorbent: 0.5 g adsorbent dosage, 0.5 M initial concentration, 50°C temperature, and 80 minutes duration, resulting in copper removal efficiencies of 98.03% and 99.78%, and arsenic removal efficiencies of 96.22% and 99.10%, respectively, for chitosan beads and chitosan-zeolite composite beads.

The combined effects of adsorbent dosage and temperature, as well as temperature and time, were found to have the most significant influence on copper and arsenic removal for chitosan beads. Similarly, the combined effects of initial concentration and time, along with adsorbent dosage and initial concentration, were identified as significant factors affecting copper and arsenic removal for both adsorbents. These conclusions were supported by F-values, which were 7.27 for Cu and 9.58 for As in the case of chitosan beads, and 17.20 for Cu and 8.69 for As for chitosan-zeolite beads.

Infrared spectrum analysis identified distinctive functional groups present in both chitosan beads and chitosan-zeolite composite beads, including -CONH-, -CH2, -CH3, C-O stretching, N-H bending, -NHC00CH3, and -NH bending. Batch adsorption experiments conducted using chitosan-zeolite beads revealed significant impacts of variables such as adsorbent dosage, equilibrium time (90 minutes), initial metal concentration, pH, and temperature on copper and arsenic removal. These results provide insights into optimal operational conditions for efficiently removing copper and arsenic from aqueous solutions.

Isotherm modeling indicated that the Langmuir isotherm best described the adsorption process, with correlation coefficients (R²) of 0.998 and 0.981 for copper and arsenic removal on chitosan-zeolite beads, respectively. The kinetics data for copper and arsenic adsorption onto chitosan-zeolite beads were most accurately modeled by the pseudo second-order kinetics, with an R² value of 0.999 even under different temperature conditions. Thermodynamic analysis revealed that the adsorption of both metals onto the adsorbent was endothermic and spontaneous, relying on van der Waals forces—a relatively weak binding force.

OPTIMIZING COPPER AND ARSENIC ADSORPTION WITH CHITOSAN-ZEOLITE BEADS, GET MORE, ACTUARIAL SCIENCE PROJECT TOPICS AND MATERIALS

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