Green and novel cleaning method by plasma-activated water on a microfiltration membrane after apple juice...

This study presents the first systematic optimization of plasma-activated water (PAW) generation parameters for cleaning fouled plasma-modified mixed cellulose ester (MCE) microfiltration membranes employed in apple juice clarification. The effects of cold plasma (CP) water activation time (5, 7, and 9 min) and electrode-to-water surface distance (20, 30, and 40 mm) on permeate flux, PAW pH, and the maximum number of effective cleaning cycles were optimized using Response Surface Methodology (RSM) to evaluate the impacts of these independent variables and their interactions simultaneously, developing predictive models with fewer experimental runs. Statistical analysis revealed that activation time, electrode-to-water surface distance, and certain interactions significantly affected all response variables (P < 0.05). Flux recovery ratio (FRR) identified a 9 min activation time and a 30 mm electrode-to-water surface distance as the optimal conditions. Unlike previous studies focused primarily on microbial inactivation and food decontamination, the present study establishes optimized PAW generation conditions for sustainable membrane cleaning and enhanced membrane reusability, considering the limited efficacy of water-only cleaning and the adverse effects of chemical cleaning to reduce chemical consumption and membrane degradation while promoting more novel and greener membrane-based separation processes in the food industry.