Dye Adsorbent from Natural Rubber Latex Foam: Efficiency and Post-Utilization

This study examined the feasibility of using natural rubber (NR) latex foam as a dye adsorbent and antibacterial foam. The dyes used in this experiment were Methylene Blue (MB) and Alizarin Yellow (AY). Foams with that optimum density were further evaluated for adsorption isotherm, kinetics, and thermodynamic data. The dye adsorption occurred in two steps: the initial and the stabilized stages where an increase in dye concentrations boosted the adsorption capacity. Based on the prediction, the maximum adsorptions of MB and AY from the solution were 3.15 and 10.31 mg/g, respectively. The Langmuir isotherm fits better with the adsorption of MB while AY is better matched by the Freundlich isotherm. Moreover, the adsorption behavior fits well with the pseudo-second-order model. MB took much longer to reach the stabilized stage, especially at high dye concentrations. The thermodynamic study revealed that physical adsorption accounted for most of the adsorption. Later, the foam after use as an adsorbent was further utilized as an antibacterial foam. Based on the qualitative and quantitative aspects, the results indicate that the dye-carrying foam could inhibit the growth of both Gram-positive and Gram-negative bacteria. It can be concluded that NR latex foam can be applied as a dye adsorbent and further utilized as an antibacterial foam.