Sustainable cocoa biowaste-based carboxymethyl cellulose/chitosan sponges for wastewater treatment applications

This study aims to develop bioactive spongy materials based on chitosan (Cs) and carboxymethyl cellulose (CMC) combined with cocoa biowaste extract (CBWE) using a freeze-drying process for environmental remediation. Two different volumes of CBWE (4 mL and 8 mL) were incorporated to form CMC/Cs/CBWE4 and CMC/Cs/CBWE8, which was compared with a spongy material that prepared without extract (CMC/Cs/CBWE0). The bioactive compounds in CBWE were analyzed via GC–MS, identifying many compounds, including oleic acid (30.07 %) and n-hexadecanoic acid (23.96 %). Antioxidant activity was assessed via the DPPH assay, which showed a maximum scavenging activity of 96.0 % at 1000 μg/mL of CBWE, with an IC₅₀ value of 17.29 μg/mL. In antibacterial testing, CBWE demonstrated dose-dependent inhibition against waterborne pathogens such as Escherichia coli, with a zone of inhibition of 28.0 mm at 100 μg/mL. The CMC/Cs/CBWE8 spongy material achieved 100 % degradation of brilliant green (BG) dye at 30 ppm catalyst dosage within 120 min, significantly outperforming the control spongy material (CMC/Cs/CBWE0), which only achieved 59 % degradation under the same conditions. Reusability tests demonstrated that CMC/Cs/CBWE8 retained 86 % of its original catalytic efficiency after five cycles, highlighting its durability. The incorporation of CBWE into CMC/Cs based spongy materials significantly enhanced their catalytic of toxic dyes and antimicrobial properties, making them highly effective for wastewater treatment applications.