[1] Anhui Agr Univ, Sch Resources & Environm, Hefei 230026, Peoples R China
[2] Anhui Environm Monitoring Ctr, Hefei 230061, Peoples R China
[3] Qinghai Univ, Sch Chem Engn, Xining 810016, Peoples R China
[4] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China