Resource recovery of Cr(VI) from electroplating wastewater: Laboratory and pilot-scale investigation using fibrous weak anion exchanger

• The fiber can be used in 80 adsorption–elution cycles with minor capacity losses.
• The multi-column system is a sustainable method for Cr(VI) removal.
• By the saturated adsorption, the Cr(VI) could be selectively enriched.
• The concentration and purity of eluted Cr(VI) were obviously enhanced by the multiple-use of eluent.

The efficient removal of Cr(VI) was investigated using fibrous ion exchange material as the adsorbent. The breakthrough and operating exchange capacities, elution and regeneration, as well as the influence factors toward the recovery of Cr(VI), were systematically evaluated. The results showed that the novel fibrous adsorbent possessed high operating capacity for Cr(VI) (approximately 400 mg/g for chromate solution, and 160–230 mg/g for various electroplating wastewater), excellent kinetic behavior (fed flow rate: 10 mL/(g min)), minor capacity losses (approximately 20%) after 80 adsorption–elution cycles. Based on above laboratory results (Q = 0.6–1.0 L/h), the resource recovery process of Cr(VI) from electroplating wastewater was developed through the pilot-scale multi-column facility (Q = 600 L/h). By the saturated adsorption and multiple-use of eluent, the chromate could be selectively enriched even from the electroplating wastewater containing SO42− and Cl− species. The concentration and purity of eluent were obviously enhanced, and could be reused in the electroplating industry.