Removal of cellulose to facilitate microplastics detection in wastewater

The presence of cellulose in wastewater can hinder the detection of microplastics (MPs) or lead to their misidentification as MPs. Existing digestion protocols, such as H2O2, are often ineffective for removing cellulosic components of organic matter. This study examined the isolation of cellulose from microplastics in wastewater using cupriethylenediamine (CED). Cellulosic materials, including cotton balls, hygienic paper, and paper rolls, were used to simulate wastewater cellulose matrices and treated with CED (0.1, 0.3, and 0.5 M) at 22 °C over varying contact times. The optimal CED condition was evaluated for its impact on microplastics (PET, PS, and PA) and applied to influent wastewater. The optimal CED (0.3 M) removed up to 100% of the cellulosic products and preserved microplastic integrity, as confirmed by 100% weight recovery, unchanged morphology from scanning electron microscopy (SEM) validated with ImageJ, and a stable carbonyl index from Fourier-transform infrared spectroscopy. Further, 0.3 M CED at 30 min isolated MPs from wastewater samples masked by cellulose, achieving 98% cellulose removal and enabling the detection of several microplastics ranging in size from 71 to 3176 μm, with PET as the predominant MPs. This work presents a rapid approach for removing cellulose, facilitating microplastics detection in wastewater.