A Nanocomposite Approach for Efficient Removal of Acidic and Basic Dyes from Wastewater Using Polypyrrole-Grafted Sodium Alginate with Bentonite Integration
摘要
We developed innovative polypyrrole-based composites using two sustainable, biologically derived resources rich in functional groups to enhance polypyrrole adsorption potential. By utilizing sodium alginate (SA) and bentonite (BN) as dispersants, we performed in-situ polymerization of pyrrole monomers to create three cost-effective composites: polypyrrole-sodium alginate-bentonite (PPY-SA-BN), polypyrrole-bentonite (PPY-BN), and polypyrrole-sodium alginate (PPY-SA). These composites were produced with a 10% wt.% feed concentration of SA and/or BN and an oxidant/pyrrole molar ratio of 1:1, resulting in average nanoparticle diameters of 71 nm, 61 nm, and 35.6 nm, respectively. We studied their specific adsorption characteristics for four dyes, noting a high selectivity for Congo red (CR), a cationic dye. The removal efficiencies of PPY-SA-BN, PPY-BN, and PPY-SA were 99.45%, 89.67%, and 97.67%, respectively, at 30 °C with an initial CR concentration of 60 mg L−1. The equilibrium adsorption period for CR was 30 min, longer than previously reported for PPY-based adsorbents. These findings suggest that the excellent adsorption ability of PPY-SA-BN arises from the interaction of nitrogen-containing groups from PPY, sulfonic groups from BN, and amino/hydroxyl groups from SA. The adsorption processes were both feasible and spontaneous, demonstrating a successful approach to creating low-cost, size-controlled PPY-based composite nanoparticles with strong dye adsorption properties.