Alginate-Modified Biochar Beads for Rhodamine B Removal: A Sustainable Approach to Water Pollution Control

Abstract

The growing demand for textiles has increased textile manufacturing, especially in developing countries, leading to severe environmental impacts from contaminated effluents. This study examined the adsorptive removal of Rhodamine B (RB) dye from aqueous solution using alginate-modified biochar beads (ALPPC, ALBPC, and ALPJC) derived from agricultural biomass: pumpkin peel (Cucurbita pepo L), plantain flower bracts (Musa acuminata), and mesquite tree bark (Prosopis juliflora). Biochar beads were prepared through ionic polymerization and characterized using SEM, FTIR, and BET analyses. Continuous mode adsorption experiments in a packed bed column system evaluated the effects of bed depth, flow rate, and influent concentration on breakthrough capacities and removal efficiency. The optimal column adsorption parameters for highest RB removal were: initial concentration 100 mg/L, flow rate 2 mL/min, and bed height 6 cm. The breakthrough curve was analyzed using Thomas and Yoon-Nelson models, with the latter closely agreeing with experimental data. Adsorption effectiveness followed the order ALPJC > ALPPC > ALBPC. The results show the potential of alginate-modified biochar composites as effective, eco-friendly, and low-cost adsorbents for treating dye-containing effluents, contributing to sustainable development goals (SDGs) by addressing rural livelihoods, converting waste to energy, and protecting water bodies' aesthetic appearance.