The efficacy of alkaline hydrolysis on selective degradation and recovery of high-purity terephthalic acid and cotton cellulose from postconsumer polyester/cotton waste

Textile waste is one of the biggest global waste problems requiring innovative and sustainable solutions. This study focused on developing a potential sustainable solution to textile waste by recycling of blended polyester/ cotton fabric waste. The blends were pretreated prior to selective alkaline degradation and then vacuum filtered into constituent materials. Terephthalic acid (TPA), ethylene glycol (EG), and cotton were the constituent materials. The effects of the processing conditions and determination of optimum conditions were ascertained by analysis of the constituent materials' properties. Electron microscopy (SEM), Ultraviolet spectroscopy (UV-VIS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyses (TGA-DSC) and viscometer were utilized in characterizing the recovered materials. The optimum processing conditions were found to be 15 % (w/v) NaOH in the presence of 1 mol BTBAC: 1 mol per repeating unit of polyester phase transfer catalyst and processing temperature and time of 80 degrees C and 270 mins, respectively. These conditions resulted in complete hydrolysis of the polyester in polyester/cotton blended fabrics waste achieving a TPA recovery rate of 80 % and recovery rate of 97 % for cotton fibres. The recovered cellulose had viscosities between 340 and 520 ml/g which is within the range of pulp utilized in the production of regenerated fibres. The successful separation of TPA and cotton fibres implies that the recycling of blended textiles can be accomplished contributing to sustainable textile waste management and circular economy. The research indicates significant potential for scalable textile waste solution to confront the increasing crisis of textile waste globally.