Optimization and application of Musa paradisiaca-derived mesoporous hydrogel beads for selective adsorption of...

Hydrogel beads were constructed using sodium alginate (SA) and banana pith powder (BPP). The ability of beads to adsorb Copper (Cu²⁺), Lead (Pb²⁺) and Nickel (Ni²⁺) was examined using SA-BPP ratios (1:1, 1:2, 1:3, 1:4, 1:5, 1:0 and 0:1). BET, FTIR, SEM-EDS, TGA and ZP were used to analyse the composite structural characteristics. BET surface area of SA-BPP (1:5) is found to be 28.308 m²/g. The impacts of adsorbent blend ratio, dosage, adsorption contact time, pH, and temperature were evaluated. The efficiency was attained at SA-BPP (1:5), 0.3 g, 180 min, pH 6 and 35°C, with adsorption rates of 83.38% for Cu²⁺, 77% for Pb²⁺ and 94.7% for Ni²⁺. The pseudo-first-order equation displayed good adsorption mechanism using (R² = 0.993, 0.998 and 0.994) for Cu²⁺, Pb²⁺ and Ni²⁺. The Freundlich adsorption isotherm fits perfectly for the adsorption process of SA-BPP (1:5) (R² = 0.967) for Pb²⁺ and Langmuir (R² = 0.979 and 0.983) for Cu²⁺ and Ni²⁺. The thermodynamic analysis shows that the adsorption process is endothermic. The removal efficiency was determined by optimizing the theoretical adsorption experiments through the Box-Behnken Design (BBD). Cumulatively, the Cu²⁺, Pb²⁺ and Ni²⁺ ions have an electrostatic nature that facilitates their easier acceptance of the SA-BPP (1:5) adsorbent electrons. After five cycles, a maximal removal effectiveness of 75% is achieved, which concludes a long-lasting adsorbent for industrial wastewater.