A Robust High-Pressure RO Technology to Overcome the Barriers to Full Circularity in Cr(III) Electroplating Operations

Electroplating is a widely used technology for anticorrosion materials and decorative coatings. In view of the transition to a circular economy, the current electroplating wastewater treatment disposing of heavy metal sludge and wastewater severely lacks sustainability. Authors recently reported the successful recycling of electroplating agents using hybrid semibatch/batch reverse osmosis technology (hybrid RO). Despite promising results, technology assessment to treat new, second-generation electrolytes, enhance boric acid recovery, close the water loops, and evaluate process robustness is still needed. This study investigates the viability of a high-pressure (120 bar) hybrid RO system, working with the DuPont XUS180808 membrane, to reclaim valuable second-generation plating components and water from electroplating rinses. The pilot-scale system showcased resilience in processing artificial electroplating wastewaters of variable concentration, achieving water recoveries of ≤87.7%, increasing chromium and sulfate to electrolyte levels (>6 g/L and >80 g/L), with low energy consumptions (≤2.7 kWh/m³), underlining its potential as a circular treatment in the chromium electroplating industry. A second-pass RO treatment strategy was explored, addressing residual boric acid in the permeate and leveraging solubility interactions to enhance its rejection, enabling water reuse. Based on these findings, an RO designed for industrial application was proposed for future scale-up and evaluation within a real-world production environment.