Enhanced cadmium (II) adsorption via calcium alginate encapsulation of HPMBP in heavy metal remediation

Heavy metal contamination from industrial activities poses serious environmental and health risks, particularly from cadmium (Cd), and the removal through adsorption using calcium alginate encapsulated with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) offers a promising solution. This study aims to improve Cd(II) ion adsorption by encapsulating HPMBP in calcium alginate beads and assess its effectiveness in contaminated water remediation. HPMBP was synthesized and encapsulated in calcium alginate beads to produce Ca-alginate-HPMBP microcapsules, characterized using FTIR), proton nuclear magnetic resonance (1H NMR), and Scanning Electron Microscopy (SEM) analysis. Adsorption experiments evaluated pH, contact time, initial Cd(II) concentration, and adsorbent mass effects. Desorption cycles were also tested to evaluate reusability, and environmental samples were examined to assess practical application. Optimal adsorption was achieved at pH 6, with Ca-alginate-HPMBP showing enhanced adsorption capacity (94.34 mg/g) compared to Ca-alginate alone (9.66 mg/g). Adsorption equilibrium was reached within five hours. Higher initial Cd(II) concentrations improved adsorption efficiency, following a Langmuir isotherm model. The material demonstrated high recovery rates in desorption cycles, and field tests with environmental samples showed a Cd(II) recovery rate of 101.89%. Encapsulation of HPMBP in calcium alginate enhances Cd(II) ion adsorption, providing an efficient, reusable adsorbent for heavy metal remediation in contaminated water sources, supporting sustainable solutions for water contamination challenges.