Ascorbic acid enhanced performance of trace Cu(II)-Peroxydisulfate in oxidation of PPCPs: Mechanism and application - Xiujuan Kong; Rui Lu; Jielian Li; Yiming Qiu; Penghui Du; Kexin Tang; Jiaxi Lu; Wangdui Bianba; Yixin Hou; Yinuo Jia (Chemical Engineering Journal, 2026)